There is often accompanying cramping, gas, and a sense of immediate urgency (the sudden need to run for a bathroom). Vomiting can be a feature of this condition though the characteristic diarrhea is the hallmark. Colitis may be acute (lasting only a few days) or chronic (lasting weeks or months on end). Even in chronic cases, weight loss is usually not a feature of this condition.

What and Where is the Colon?

The colon is another term for the large or lower intestine. For those who do not know the lower intestine from the upper intestine, the colon/lower intestine is basically the last segment of the digestive tract. Before reaching the colon, food has been extensively processed. It has already been chewed up in the mouth, acid-treated in the stomach, and enzyme-treated in the small intestine. Most of the nutrients have already been absorbed by the time the undigestible leftovers have passed down to this last part of the GI tract.

But the digestive tract is not through with the food remnants quite yet and this is the where the business of the colon comes in. The colon has three functions: absorbing water, storing stool, and further digesting unabsorbed nutrients. The bacterial population in the colon is about 10 times more dense than that of the small intestine. These bacteria, often referred to as  good or helpful bacteria, take fibers that were undigestible to the host and actually process them into biochemicals that provide nourishment to the colon cells. The bacteria that live in the colon not only feed the cells of the colon, but they also control the pH of the colon environment so that excreted toxins are trapped in the stool and will be pooped away rather than reabsorbed back into the body. They also produce flatulent gases and pigments that lead to the ultimate color of stool. The relationship we have with our colon bacteria is mutually beneficial and is an excellent example of symbiosis.

Diarrhea Can Come from Either the Small Intestine or the Large Intestine and the Approach is Different in Either Case

In classifying diarrhea, it is important to determine whether the problem originates from the small intestine, the colon, or possibly both.  Small intestinal diarrheas tend to be more serious as they involve fundamental problems with obtaining nutrients from food. Diarrheas of the colon are less debilitating but still uncomfortable.

The following are characteristics of large intestinal diarrhea:

• Large intestinal diarrheas are generally not associated with weight loss, and patients generally have normal energy levels and normal appetites.
• Large intestinal diarrhea is associated with straining to defecate. Often, this straining is unproductive, leading to the erroneous conclusion that the patient is constipated.
• There is cramping, flatulence, and a sudden sense of urgency. The pet may not be able to get to an appropriate area before the diarrhea erupts.
• There is often mucus or slime in the stool
• There is often fresh blood in the stool.
• The stool may begin looking normal and formed but finish as a puddle.

A diagnosis of colitis is generally straightforward given the above classic findings, though how to proceed depends on the signs. Is the problem acute (i.e., suddenly there) chronic (has been happening for several weeks regularly), or episodic (happens then goes away, then happens again)?

Colitis Suddenly (Acute Colitis)

A pet that has sudden symptoms of colitis probably has stress-related colitis (common after boarding, moving, severe weather, or other change) or dietary indiscretion-related colitis (usually involves treats or raiding the garbage). These episodes are generally minor and can be cleared with a short course of medication such as metronidazole or sulfasalazine and/or dietary therapy. Parasites, especially Giardia and whipworms, can also cause colitis and the pet may be tested for those to rule them out or be dewormed. In general, a few days of medication and a bland diet should resolve the problem and the pet will be back to normal quickly. During recovery, it is common for the pet to have no stool at all for a couple of days. This is normal and not a sign of constipation. If, however, the pet’s diarrhea is not clearly improved in two to three days, contact the veterinarian to see if further testing is needed.

Diagnosing the Cause of Colitis

If the symptoms of colitis have been going on for a month or more or if they keep recurring and resolving over and over, then a medical workup is needed. It is important to make sure simple causes of colitis have been ruled out, so parasite testing becomes especially important.

A good fecal examination for worms and coccidia plus additional testing for giardia should be performed. If any of these tests are positive, then obviously the parasite in question can be addressed; it is always best to identify the cause of the colitis if it is possible to do so. That said, even if these tests are negative, it is still a good idea to include a broad spectrum de-worming and coccidia treatment, which should probably be given as these treatments are safe and inexpensive. Whipworms, in particular, are difficult to detect and commonly cause colitis symptoms. We want to be sure we have ruled out the simple causes of colitis before more advanced diagnostics begin. Similarly, a week or so of metronidazole, sulfasalazine, or tylosin may effectively treat a toxin-producing Clostridium perfringens infection and potentially solve the entire problem. Of course, a basic blood panel and urinalysis are in order, as they are with any chronic disease, to assess the patient’s general health.

After all the preliminaries above are covered, the patient is assessed for results. If it doesn’t look like one-time treatment of deworming, antibiotics, or diarrhea medication is going to solve the problem, then diagnostics continue to the next level. Most reference labs now have the capability to do PCR (DNA) testing for more obscure organisms such as Tritrichomonas in cats, Cryptosporidium in dogs and cats, and more. This is testing uses a fecal sample and can be used to non-invasively rule out unique infections.

The last step in colitis diagnostics is a colonoscopy with biopsies with the idea of examining colon tissue under a microscope to classify the inflammation. Depending on the type of cells infiltrating the colon lining, the colitis can be classified as lymphocytic/plasmacytic (a form of inflammatory bowel disease), histiocytic (which tends to stem from a type of E. coli infection,) or not truly colitis at all and the entire problem may be the psychosomatic condition known as irritable bowel syndrome. All these conditions have different treatments.

A colonoscopy requires a period of fasting (usually a couple of days) and enemas or some other kind of fluid to clear the colon of residual stool so the naked tissue of the colon can be viewed and sampled. Referral to a specialty hospital is likely needed. Colonoscopy is performed under general anesthesia and not every patient is a candidate for that, plus expense may be a concern. These disadvantages must be weighed against the quality and quantity of information that can be obtained by evaluating a tissue sample from the colon.

Depending on your pet’s specific case and the cause of colitis, your veterinarian may or may not recommend antibiotics. 

Management Tips for Colitis

Colitis is best managed when its cause is known and specific therapy can be instituted. When this is not possible, symptomatic management is often attempted. The following are therapeutic medications and strategies that can be helpful in the treatment of colitis.

Metronidazole and Tylosin

These medications are antibiotics with anti-inflammatory properties in the large intestine and the ability to kill harmful organisms.

Sulfasalazine

This medication consists of a sulfa antibiotic bound to a salicylate anti-inflammatory. The sulfa bond protects the anti-inflammatory medication until it gets to the large intestine, thus saving the anti-inflammatory effect for the disease of the large intestine. This is an effective medication but is typically given three times a day, which is an inconvenience. Cats are sensitive to salicylates, thus this medication is primarily used in dogs.

Dietary Fiber

The role of fiber in colitis is confusing as there is an assortment of fiber preparations (soluble fibers, insoluble fibers, and mixtures). In general, colitis is felt to be a fiber-responsive disease, but there are so many combinations of fiber types that it is hard to know what the patient may be responding to. Insoluble fibers, like cellulose, bulk up the stool and are stimulating to the colon lining. This may not be what is in order if the colon is already irritated although giving some structure to diarrhea may be a good thing. Soluble fibers, like psyllium, are fermented by the colon bacteria into nutrients for the colon cells, which helps them heal. Prescription high fiber diets often have a mixture of soluble and insoluble fibers that have been scientifically determined to help colitis patients. Alternatively, a low residue diet (one of high digestibility) could be used and soluble fiber added to it. The idea with this strategy is to have maximum intestinal absorption of nutrients in the small intestine so less material enters the colon, but once the material gets there the soluble fibers added help the colon cells to heal.

Prebiotics such as Fructooligosaccharides (FOS)

Prebiotics are basically food for beneficial colon bacteria. Feeding a diet rich in prebiotics promotes a healthy colon bacterial population, which in turn helps resolve diarrhea.

Fructooligosaccharides are carbohydrates involving fructose (fruit sugar) units attached to glucose (starch sugar) units. Regular dietary carbohydrates are digested by the bacteria of the small intestine, leaving only the undigested fibers and other dregs for the teeming masses of the large intestine. FOSs are not fibers but they are digested in the large intestine (not the small intestine) in the same way that fibers are, yielding the same biochemicals that fibers do. Why is this good? Tests in healthy animals indicate that this will help remove pathogenic bacteria from the large intestine and promote growing helpful bacteria. Think of it as an anti-crime program in the New York City of bacteria. Diets that contain FOSs or other prebiotics may be helpful in managing colitis. Several such diets are available.

Probiotics

A probiotic is a protected culture of live helpful bacteria that can colonize the patient’s intestine. The bacteria must be protected from the acid of the stomach so as to survive to the lower intestine. Once there, the bacteria make a home and make by-products that are nourishing to the intestinal and local immune system cells. There are numerous products on the market for both humans and animals; the problem has been that since these products are not regulated as drugs by the FDA, they are required only to be safe, not necessarily effective. In fact, a recent study found that most such products do not actually contain the live cultures they are advertised to contain. If you want to add a probiotic to a pet’s regimen, we recommend sticking to well-established veterinary companies. That said, probiotics are mainly made to colonize the small intestine, not the large intestine, so their benefit in colitis is still somewhat speculative.

Elimination Diet

Colitis can result from a food intolerance (an example would be lactose intolerance from which numerous people suffer). Intolerances can result from dyes, preservatives, contaminants or even natural proteins in the food. Similarly, colitis can result from an actual food allergy. The solution for these intolerances is the feeding a “pure” diet, ideally a home-cooked food made with carbohydrates and proteins that are novel or new to the patient. An 8 to 10 week diet course is typically needed and no other chews or treats can be eaten during the trial. Food allergy cannot be diagnosed by blood test or skin test. At this time, response to an elimination diet is the only test for food allergy or intolerance.  Most people are not in a position to home cook an appropriate food for their pet. Fortunately, several novel protein diets and hydrolyzed protein diets have been developed. For more details on using an elimination diet, see our food allergy page.

Prednisone is the cornerstone of treatment for inflammatory bowel disease, which must be diagnosed by biopsy. Sometimes a trial course of this medication is suggested for colitis but it is important to keep in mind that such trials can interfere with future diagnostics and can create some degree of immune suppression. Prednisolone could be disastrous in the event of an E. coli-related histolytic colitis, for example. Many patients with inflammatory bowel disease are never able to fully discontinue prednisolone, so be sure to discuss the pros and cons of attempting this therapy without a biopsy.

Histiocytic Ulcerative Colitis: A Specific Form of Colitis

This condition is also called Boxer colitis because the Boxer breed seems predisposed. This form of colitis is particularly ulcerative and involves infiltration of the tender colon lining with cells called histiocytes. These cells are the cells that are normally called into the scene of inflammation relatively late so that they can absorb the dead cells and debris that have been created by the inflammatory event.

Dogs with this condition typically show symptoms at an early age (less than two years) and become more debilitated than typical colitis patients. It is currently believed that this condition results from an inappropriate immune response against the common bacteria of the colon, especially E. coli. Dogs with this form of colitis do not respond well to the usual remedies listed above but instead seem to show an excellent response to the antibiotic enrofloxacin. This antibiotic is particularly effective against gram negative bacteria (so classified because their cell wall’s staining properties when tested). It has thus been inferred that these bacteria are at the root of the problem.

Histiocytic ulcerative colitis can be confirmed by biopsy, although signs of colitis in a young Boxer are highly suggestive of this condition.

In Summary:

•   The colon is another term for the large or lower intestine.
•   The colon has three functions: absorbing water, storing stool, and further digesting unabsorbed nutrients. 
•   Inflammation of the colon is called colitis. Diarrhea is a characteristic sign; the condition may be accompanied by cramping, gas, and vomiting. Weight loss is usually not a feature.
•   Colitis may be acute (lasting only a few days) or chronic (lasting weeks or months).
•   There are “good’, or “helpful” bacteria that live in the colon and small intestine.
•   It is important to find whether diarrhea originates from the small intestine, the colon, or possibly both.
•   Small intestinal diarrhea tends to be more serious as it prevents food nutrients from being absorbed.
•   Diarrhea of the colon are less debilitating but are still uncomfortable.
•   Acute (or sudden) colitis can be stress-related or dietary, is usually mild, and can be cleared up with a short course of medication or a change in diet.
•   Chronic, or recurrent, episodes of colitis mean the signs have been going on for a month or more, and this means a medical work up will probably be recommended by your veterinarian.
•   Colitis is best managed when the cause is known and specific therapy can be instituted.
•   Many different parasites can cause colitis, including coccidia and giardia.
•   Food intolerance from dyes, preservatives, contaminants, or even natural proteins in the food can cause colitis.
•   If other reasons have not been found, the last step in colitis diagnostics is a colonoscopy with biopsies to exam colon tissue under the microscope to classify the inflammation.
•   Antibiotics that have anti-inflammatory properties in the large intestine as well as the ability to kill harmful organisms are often prescribed.
•   An elimination diet to narrow down foods that may not be tolerated by your pet can be helpful.  
•   Dietary fibers and pro- and pre-biotics may be suggested, as soluble fibers ferment by colon bacteria into nutrients, which help the colon heal. Prescription high-fiber diets often have a mixture of soluble and insoluble fibers that have been scientifically determined to help colitis patients.
•   Histiocytic Ulcerative Colitis, also called Boxer colitis, is a condition in which the Boxer breed seems predisposed. This form of colitis is particularly ulcerative and involves infiltration of the tender colon lining with cells called histiocytes.

What on Earth are Coccidia?

Coccidia are single-celled organisms that infect the intestine. They are microscopic parasites detectable on routine fecal tests in the same way that worms are, but coccidia are not worms and are not susceptible to deworming medications. They are also not visible to the naked eye. Coccidia infection causes watery diarrhea that is sometimes bloody and can be a life-threatening problem to an especially young or small pet. There are many different species of coccidia but for dogs and cats, the most common infections are with coccidia of the genus Cystoisospora. Dogs and cats each have their own coccidia species and cannot infect each other, nor can they infect people.

Where do Coccidia Come from?

Oocysts (pronounced o’o-sists) are passed in the stool. In the outside world, the oocysts begin to mature or sporulate, which leaves them able to infect a new host. It only takes 12-36 hours for an oocyst to become infective and after that, any host that accidentally swallows the oocyst will probably be infected. Because the oocyst becomes infective in such a short time, it is important to remove stool as quickly as possible so that the pet’s environment does not become contaminated with infective oocysts.

Coccidia infection is especially common in young animals housed in groups (in shelters, rescue areas, kennels, etc.) This is a common parasite and is not necessarily a sign of poor husbandry.

Oocysts can also be swallowed by mice, flies, cockroaches or other insects. A dog or cat can be infected by eating an animal carrying an oocyst.

What Happens after the Host Consumes the Oocyst?

This gets a little complicated, but the short version is that the oocyst breaks open and releases eight sporozoites. These eight sporozoites go on to infect intestinal cells and, once inside these cells, they divide rapidly over and over until a new stage called a merozoite results. The merozoites divide and reproduce rapidly, filling up the intestinal cell until it bursts. A multitude of merozoites are released when the cell bursts and they go on to infect and similarly destroy more and more intestinal cells. When enough intestinal cells are destroyed, in three to 11 days, bloody watery diarrhea and disease result.

Merozoites divide and reproduce asexually but eventually a sexual generation of coccidia results in microgamonts, which are male, and macrogamonts which are female. They merge and create an oocyst, which is what started the whole thing in the first place. The oocyst passes in stool where it can infect a new host and the life cycle begins again.

How are Coccidia Detected?

A routine fecal test is a good idea for any new puppy or kitten whether there are signs of diarrhea or not as youngsters are commonly parasitized. This sort of test is also a good idea for any patient with diarrhea and is recommended at least once a year for healthy dogs and cats as a screening test. Coccidia are microscopic and a test such as this is necessary for diagnosis. Small numbers of coccidia can be hard to detect, so just because a fecal sample tests negative, this doesn’t mean the pet isn’t infected. Sometimes several fecal tests are performed, especially in a young pet with refractory diarrhea (one that won’t go away); parasites may not be evident until later in the course of the condition.

How is Coccidia Treated?

There are two common treatments used for Cystoisospora infections in pets: sulfa drugs (the traditional treatment) and coccidiocidal medications (newer treatment). The most common medicines used against coccidia are called coccidiostats. They inhibit coccidial reproduction. Once the numbers stop expanding, it is easier for the patient’s immune system to catch up and wipe out the infection. This also means, though, that the time it takes to clear the infection depends on how many coccidia organisms there are to start with and how strong the patient’s immune system is. A typical treatment course lasts about a week or two, but it is important to realize that the medication should be given until the diarrhea resolves plus an extra couple of days. Medication should be given for at least five days in total. Sometimes courses as long as a month are needed. In dogs and cats, sulfa-based antibiotics are the most commonly used coccidiostats.

There are newer medications that actually kill the coccidia outright: ponazuril and toltrazuril, both actually being farm animal products that can be compounded into concentrations more appropriate for dogs and cats. These medications are able to curtail a coccidial infection in only a few doses and have been used in thousands of shelter puppies and kittens with no adverse effects. Their use is becoming more popular used in kennels, catteries, and animal shelters and you may be pleasantly surprised to find one of them in stock at your regular veterinary office.

Can People or other Pets Become Infected?

While there are species of coccidia that can infect people – Toxoplasma and Cryptosporidium, for example – the Cystoisospora species of dogs and cats cannot infect people. Other pets may become infected from exposure to infected fecal matter but it is important to note that this is usually an infection of the young (i.e. the immature immune system tends to let the coccidia infection reach large numbers whereas the mature immune system probably will not.) In most cases, the infected new puppy or kitten does not infect the resident adult animal.

Decontaminating the home environment may also be recommended by your veterinarian. Since the oocysts are resistant to most commonly used disinfectants, prompt removal of all stool, then scrubbing any soiled areas with a detergent, will be the best environmental measure. 

What is Clostridium perfringens?

Clostridial diseases are classic in medicine, both veterinary and human. It is a Clostridium that causes tetanus and botulism, and clostridia are responsible for gangrene, “black leg,” lamb dysentery, and other famous maladies.

Clostridia have several features in common that make them especially nefarious but most importantly:

• They produce toxins.
• They are anaerobic (they grow in the absence of oxygen).
• They form spores (essentially armor) so as to withstand environmental change, including disinfectants that would kill more vulnerable bacteria.

Clostridium perfringens is one of the brothers of the evil Clostridium family but is further classified into five biotypes (A, B, C, D and E) depending on what combination of four toxins it produces. Dogs are almost exclusively infected with biotype A.

The toxins of significance that it can produce are called enterotoxins. We are particularly concerned about the alpha, epsilon, and net E/F toxins. These toxins can be seen in normal dogs, but if they are in high enough amounts, they are associated with diarrhea.

How Would Clostridium perfringens Infection Happen?

In order to produce toxin(s), the organism must form a spore (sporulate). Before it can do that, it must make its way into the host’s intestine from the outside world. The organism enters the body orally: in food, grooming of fur, chewing up rotten dead things, etc.

When the organism arrives in the small intestine, it forms a spore and begins to produce its toxin(s). Alternatively, the organism may have been happily and innocuously living in the intestine for who knows how long when something causes it to sporulate and produce toxin.

The trigger may be dietary, may be related to infection with another organism, or may even be related to medications, especially antibiotics. The type of diarrhea produced is generally a colitis, meaning the large intestine is affected. Such types of diarrhea are mucousy, possibly bloody, and associated with straining. More watery diarrhea, as comes from the small intestine, is also possible. The severity of the diarrhea can range from mild to life-threatening, depending on how much toxin is produced. The important concept is that C. perfringens toxin can be the cause of chronic diarrhea, or it can be a complicating factor in diarrhea caused by something else.

Can we Test for Toxin-Producing Strains Of Clostridium perfringens?

The culture will not tell us if the strain present can produce the enterotoxin. Clearly, we need to know more than whether there are any C. perfringens. How about culturing for Clostridium perfringens? Again, cultures are not very helpful. Clostridium perfringens can be cultured from the feces of 80% of dogs, whether they have diarrhea or not. Some dogs seem to be unaffected.

This is where PCR testing comes in; it is a form of DNA testing whereby the C. perfringens are tested for the DNA needed to make the different enterotoxins. In this way, we can detect the genes that are capable of producing enterotoxin. Furthermore, the number of gene copies can be measured so that we can tell if there are large or small amounts of toxin genes. Large amounts of toxin genes are associated with disease, so in this way, we can tell if one of the Clostridium perfringens enterotoxins is likely to be contributing to the patient’s diarrhea. 

There is also a test for the toxin, but it is an ELISA format, which means it is either negative or positive and does not say how much or how little toxin is present. In a perfect world, this test is combined with the test for the toxin-producing genes so as to confirm that not only are there large amounts of toxin genes, but they are confirmed to be producing toxin.

The severity of the diarrhea can be mild all the way to life-threatening.

When Should We Treat for Clostridium perfringens?

Let’s begin with the obvious: a pet does not need to be treated for C. perfringens unless he has diarrhea. Since 80% of dogs harbor Clostridium perfringens whether they have diarrhea or not, culturing Clostridium perfringens from a fecal sample will not be adequate for diagnosis; we have to find the toxin or, at the very least, verify the presence of significant amounts of Clostridial genes capable of producing toxin. And all this must be found in a patient that actually has diarrhea.

The chances are that a fecal check for worms has been done, and a trial course of an anti-diarrheal medication has been tried. A possible next step would be a PCR panel that detects the DNA from an assortment of viruses and bacteria associated with diarrhea. Often this type of panel includes a test for Clostridial enterotoxin DNA. The laboratory will report a quantification of gene copies for CPA (the gene for the alpha toxin), CPE (the gene for the epsilon toxin), and CP net E/F (the gene for the net E/F toxin). If the number of toxin genes for any of these toxins is significant, treating with antibiotics against Clostridium is indicated.

Keep in mind that Clostridial diarrhea might be the entire problem and curative with the right antibiotic or it might be secondary to a bigger problem yet to be discovered. Treatment for significant Clostridial diarrhea thus might yield only partial results.

Treating the Toxin-Positive Dog with Diarrhea

Any number of antibiotics can be used to remove it. Some choices include ampicillin, amoxicillin, metronidazole, erythromycin, and tylosin. Tetracycline was formerly on the list, but it has developed too much resistance.  If C. perfringens is responsible for the diarrhea, a response to antibiotics is generally seen in a couple of days, but the full course of medication your veterinarian prescribed should still be completed.

Infestations of the skin tend to occur around the head and neck because the animal has stuck its head near a burrow that contains the eggs. Once a larva hatches, it can be licked and swallowed during grooming, enter the body via the mouth or nostrils, or it may enter through an open wound. The larva causes a lesion in subcutaneous (below skin) tissue. [See special note below.] The host acts like an incubator. The larva opens a tiny breathing hole (a fistula) in the skin. It just lives there, as though renting space; it does not feed on the host. An advanced-stage larva is the size of the first joint of your thumb and is a light tan color. 

About a month after infestation, the Cuterebra larva crawls out of the skin to pupate and then emerge as an adult fly to begin the cycle. The length of time it stays in the ground depends on seasonal factors. 

What pet owners typically see is the swelling at the air hole and matted hair from the pet’s over-grooming. Cats often groom to the point of irritation. Sometimes the pet has pain at the site. Some sites become infected and pus can be seen. Your veterinarian can diagnose cuterebriasis just by visual inspection. 

Removing the larva is one of the simplest things in veterinary medicine; your veterinarian will probe and enlarge the breathing hole, grasp the parasite with forceps, and just pull the invader out. Squeezing the lesion with your fingers can rupture the larva and cause an infection. The larva should be removed as a whole piece, rather than in parts, in order to reduce the body’s reaction. Typically, no other treatment is required, although sometimes the wound will need to be flushed with saline, debrided (unhealthy tissue removed), or covered with antibiotic ointment. Because of the “housing” that was created around the subcutaneous parasite, it may take longer to heal than you might expect, but it will heal.

Special Note

The most common problem with Cuterebra is the subcutaneous site infestation. However, occasionally aberrant migration of Cuterebra spp. can occur in other tissues and can cause more significant disease. 

Ophthalmomyiasis externa occurs when larvae infect the conjunctiva (the mucous membrane that lines the inner surface of the eyelids and is continued over the forepart of the eyeball), the skin around the eyes, and the eyelids.

Ophthalmomyiasis interna anterior occurs when larvae are in the anterior segment of the eye’s globe.

Ophthalmomyiasis interna posterior occurs with larvae in the posterior segment.

Cuterebra spp. larvae have been found in the central nervous system (CNS) in some patients, leading to severe neurologic abnormalities. For example, cerebrospinal cuterebriasis has been associated with ischemic encephalopathy in cats.

Migration of larvae through the nose, trachea, pharynx, and larynx has also been reported. Other abnormalities, such as disseminated intravascular coagulation (DIC), systemic inflammatory response syndrome (SIRS), and protein losing nephropathy, have occurred in dogs.

Chemical injuries to tissue are caused by contact with harmful chemicals such as lye, acids, and strong cleaning supplies.  Also called chemical burns, they can be similar to thermal (heat) burns and treatment can be complex and last many weeks. Prompt removal of the chemical agent and rapid veterinary medical attention can help minimize the injury and speed healing.

ASPCA Animal Poison Control Center Phone Number: (888) 426-4435

Pet Poison Helpline:  (855) 764-7661

What to Do

• Seek veterinary care immediately.
• Avoid being bitten by using a muzzle on your pet if you think there is a risk of being bitten.
• Wash the contaminated area with large volumes of tepid (lukewarm), flowing water for at least 15 minutes.  
• In the case of dry chemicals, brush them away carefully, taking care to protect the eyes, nose, and mouth of both you and your pet.
• If the chemical is in the eye, flush the eye with large volumes of water or contact lens saline for 15 minutes. (See below for the saline recipe.)  
• Make sure the area is well-ventilated as some chemicals can release strong fumes.

What NOT to Do

• Do not apply neutralizing agents to the skin or eyes. They can cause a chemical reaction that produces heat and cause further injury to tissues.  
• Do not immerse your pet in non-flowing water if a dry chemical has spilled on him or her. These dry chemicals are usually activated by water. The water must be flowing in order to rinse the chemical away.

Pure water can be quite irritating to the eyes and raw skin. It is much more comfortable for your pet if you use saline: simply dissolve 2 teaspoons of table salt in one quart of water (metric: 9 grams of salt in 1 liter of water).

1. Bad breath (halitosis) 
2. Broken tooth/teeth
3. Excessive drooling
4. Reluctance to eat, especially dry food, or to play with chew toys
5. Chewing with or favoring one side of the mouth
6. Pawing at or rubbing the muzzle/mouth
7. Bleeding from the mouth
8. Loss of symmetry of the muzzle and/or lower jaw
9. Swollen/draining tracts under (or in front of) the eye
10. Sudden change in behavior (aggressive or withdrawn)
11. Chronic eye infections or drainage with no exact cause or cure
12. Inability to open or close the mouth
13. Chronic sneezing
14. Discolored tooth/teeth
15. Abnormal discharge from nose
16. A mass/growth in the mouth

If you see any of these clinical signs, take your pet to your veterinarian for a complete oral examination.  Your veterinarian may need to sedate or anesthetize your pet, in order to complete the examination..  Dental radiographs (X-rays), not “skull films” (a radiograph of the entire head) may be necessary in order to make a proper diagnosis.  Intra-oral radiographs are essential for deciding what’s going on and what needs to done.  If your veterinarian is unable to take dental radiographs, is unsure of a diagnosis, or if the treatment is beyond the clinic’s level of dental experience, ask for a referral to a veterinarian who has an advanced certification in dentistry. (See American Veterinary Dental College or Academy of Veterinary Dentistry).

Preventive care involves brushing and daily examination of your pet’s mouth. Brushing needs to be done at least 3 to 4 times a week, if you want to make a difference in your pet’s oral health.  Plus, by looking in your pet’s mouth while you are brushing, you will be more aware of any oral abnormalities (oral masses, bad breath, missing teeth) or the increased redness of the gums that indicates periodontal disease and the need for a trip to the “Animal Dentist.”

By working with your primary-care veterinarian and a dental specialist, you are sure to increase your companion’s quality of life by providing proper and timely dental and oral healthcare.

Like people, our pets’ bodies develop cancer cells throughout their lifetime. In the lucky ones, these cells remain dormant and no malignancy ever grows; in others, the cells go mad systematically. The cellular delinquents bust past the body’s natural immune system, as though a gate was left open, burgeoning into abnormal cells. They do not surrender to a healthy cell’s programmed death, so the cellular delinquents multiply as they crowd out healthy cells. They don’t follow any rules and ignore signals that they are overfilling the place. For nourishment, they cause new blood vessels to form to supply them, which should be supplying healthy tissue.

• Lumps and bumps that don’t go away
• Wounds that don’t heal, particularly if their appearance is changing
• Limping or other signs of pain while walking, running, or jumping
• Unexplained weight loss
• Less energy, less willingness to play, walk, and run
• Difficulty breathing
• Bleeding, including nosebleeds, skin bruises, blood in stool, urine, or vomit; pale gums can show blood loss
• Bad odors from the mouth, ears, or anus
• Abnormal discharge such as blood or pus; vomiting or diarrhea, particularly if accompanied by other signs
• Behavior changes such as lethargy, depression, lack of appetite, snapping
• Changes in urinary and bowel habits, such as straining or going too often

They range from subtle to more obvious that something is going wrong. Signs of cancer can be similar to ones seen in other diseases, so don’t assume your pet has cancer if you see one. Also don’t assume that age alone is causing lethargy or lack of playfulness.

If your pet has one or more of these signs, it’s time for a visit to the veterinarian: catching any disease process early is best because it’s easier to treat.  With cancer, early detection can sometimes make the difference between good health at a reasonable cost and an expensive illness that may include death.

First, the Basics

The lungs are the focus of this topic. The diaphragm and rib muscles extend and contract to draw breath into the lungs and expel it again. In many ways, the lungs are like sponges filled with air. Life depends on the ability of their small chambers to expand with new air and contract to expel used air.  There is not a lot of extra room inside the chest cavity, so when something (such as fluid) starts taking up space in the chest, the lungs do not have room to inflate to their natural capacity. Breathing becomes hard work, and the patient’s focus becomes expanding the lung against limited space, sort of like trying to blow up a balloon that is too stiff. The fluid inside the chest cavity is called “pleural effusion.”  This fluid is not actually inside the lungs and generally does not lead to coughing or sputtering; it instead surrounds the lungs, making lung expansion difficult, leading to shallow rapid breaths and recruitment of the abdominal muscles to lend strength to the act of breathing.

Types of Fluids

There are many types of fluids that can accumulate in the chest cavity. When the fluid is blood, the problem is called hemothorax. When the fluid is pus, the problem is called pyothorax. When the fluid is actually air, the problem is pneumothorax. When the fluid is lymph, the problem is called chylothorax. With chylothorax, the fluid is milky when it is drained from the chest, and its whiteness is from fat. Chylothorax represents a specific problem and requires specific therapy.

Initial Tests

The effort the patient is making to breathe will probably be the first sign of trouble, and upon seeing this, your veterinarian is likely to recommend radiographs. On those, fluid in the chest will be obvious. From there, the chest will need to be tapped with a needle and the fluid drained. This will create some relief for the patient as the lung will once again be able to expand. The fluid will most likely need to be sent to the lab for testing to determine the type. If the patient is too distressed for radiographs, the chest may be immediately tapped to see if there is fluid pressure that can be relieved. After the fluid has been removed from the chest, new radiographs are often taken to see if there are any structures (such as masses or heart chamber enlargements) that have become visible now that the overlying fluid is gone. 

What is Lymph?

Part of the circulatory path of lymphatic fluid involves certain lymph vessels of the GI tract called lacteals, which are involved in the absorption of dietary fat. Because of this influx of fat, lymphatic fluid is milky white. Lymphatic fluid/chyle contains fat, water, and lymphocytes (cells of the immune system). We all know what blood is. We all know that blood circulates in veins and arteries and is moved by the pumping action of the heart. In fact, there is another circulatory system in the body: the lymphatic system. Lymphatic fluid, also called “lymph” or “chyle,” represents extra fluid draining between the cells of the body, gradually channeling into lymph vessels. The fluid is moved in these vessels by the natural movement of the body’s muscles, and on its way, it picks up assorted cellular debris and carries it along its route like driftwood. Lymph fluid (and its cellular driftwood) circulates through the lymph nodes, where cells of the immune system are exposed to the driftwood. In this way, the immune system sees the remnants of infection, tumor cells, foreign organisms, etc., and can react appropriately. Some immune cells circulate in the lymphatic fluid, facilitating the immune reaction and participating in the body’s defense.

When something goes wrong with the circulation of the lymph fluid and back pressure is created, lymph fluid can leak out and accumulate in the chest.

When the Diagnosis is Chylothorax

If there is a reason for the chyle build-up, it is important to find that reason. Often (especially in cats), the reason is heart disease. Heart disease generally interferes with lymphatic drainage, and poor drainage leads to chyle build up, but there can be other reasons for chyle buildup besides heart disease. Any sort of mass or growth in the chest could also be responsible. If a cause can be found, then it should be addressed if possible. If no cause can be found, then the condition is termed idiopathic and is simply managed either medically or surgically. An echocardiogram/ultrasound of the chest is almost always needed to rule out chest masses and assess the patient for heart disease. Most cases of chylothorax are idiopathic.

Breeds that seem predisposed include Siamese and Himalayan cats, and Afghan hound and Shiba Inu dogs.

Cats are diagnosed with chylothorax approximately four times as often as dogs.

When the Diagnosis is Idiopathic Chylothorax

There are several options for treatment, though they have pros and cons. The most conservative method is medical management. This means that whenever the patient seems to be having some distress, the chest fluid is drained (see video of a fluid drain). How often this is necessary is highly individual, but every few weeks is a common interval. In time, after many taps, scarring can build up to cause the fluid to loculate, which means that small pockets of fluid form rather than one drainable area. This makes tapping more difficult over time. Other problems with periodic tapping are the potential to introduce an infection with the needle stick and the fact that chyle is an inflammatory fluid that can, over a long time, create some problematic scarring between the chest wall and the lung. This is called restrictive or fibrosing pleuritis and is definitely something to avoid (see below).

A supplement called rutin may help. Rutin is available in vitamin stores and acts to stimulate cells called macrophages to carry away some of the fat in the chyle. In some individuals, this supplement is helpful in reducing the amount of chyle build-up.

Another treatment involves somatostatin, a chemical normally produced in the brain to regulate intestinal hormone and enzyme secretion. One of its effects is to reduce chyle flow through the thoracic duct. A commercial product can be used in pets, but its use should be considered somewhat experimental.

A low-fat diet (approximately 6 percent fat on a dry matter basis) is generally also used in conjunction with the above. Medical management such as this is often recommended before surgery, as some cases of chylothorax will spontaneously resolve.

Treatment

In many cases, the cause of chylothorax cannot be defined. In this situation, chylothorax is said to be idiopathic, and it must be treated without the benefit of treating its underlying cause. There are several options for treatment, though they have pros and cons. The most conservative method is medical management. This means that whenever the patient seems to be having some distress, the chest fluid is drained.  How often this is necessary is highly individual, but every few weeks is a common interval. In time, after many taps, scarring can build up to cause the fluid to loculate, which means that small pockets of fluid form rather than one drainable area. This makes tapping more difficult over time.

A supplement that may help is called rutin. Rutin is available in vitamin stores and acts to stimulate cells called macrophages to carry away some of the fat in the chyle. In some individuals, this supplement is helpful in reducing the amount of chyle build-up.

A low-fat diet (approximately 6% fat on a dry matter basis) is generally also used in conjunction with the above.  Medical management such as this is often recommended before surgery, as some cases of chylothorax will spontaneously resolve.

More permanent solutions require surgery. 

Thoracic Duct Ligation and Pericardiectomy

The thoracic duct is the largest lymph vessel in the body, and it runs alongside the aorta (the largest artery in the body) through the chest. Lymph fluid flows through it on the way to the subclavian artery, where it dumps into the bloodstream. When the thoracic duct is tied off, lymph fluid must find other channels for circulation, and the flow of lymph through the chest is greatly reduced. Ligation (tying off) of the thoracic duct resolves the chylothorax in approximately 50% of dogs and less than 40% of cats. See a video of thoracic duct ligation in a cat.

Success is hugely increased by stripping the pericardium from around the heart.

The pericardium is the fibrous sac containing the heart. When it is bathed in chyle, it becomes thickened and may slightly constrict the low-pressure right side of the heart. This causes increased pressure on the right side of the heart, which in turn causes increased pressure in the lymphatics. Stripping the pericardium relieves this pressure, and when thoracic duct ligation is combined with pericardiectomy, chylothorax resolved in 100% (10 out of 10) dogs studied and in 80% of cats studied. This is now the surgery of choice for chylothorax in cats and dogs.

Cisterna Chyle Ablation

The cisterna chyle is a structure where lymph collects just before it flows into the thoracic duct. The removal or destruction of the cisterna chyle further diverts lymph flow away from the chest. This procedure is generally reserved for patients who did not find success with thoracic duct ligation/pericardiectomy.

Complications

It can take up to 50 days to realize the benefits of surgery for chylothorax. Some animals simply will not achieve adequate resolution, and some (as many as 30% of dogs) will resolve their chylothorax only to develop some other type of chest fluid. The simple use of prednisone as an anti-inflammatory measure can resolve such fluid in as many as 60% of dogs, though it takes four to six weeks. If this is ineffective or a more rapid solution is needed, a port can be surgically placed under the skin to allow for easy fluid drainage, or a pump can similarly be placed to allow the owner to pump fluid from the chest into the abdomen.

Beware of Fibrosing Pleuritis

Chyle in the chest is irritating to the local tissue; the lungs can develop scarring from being in contact with chyle. Scarring prevents the lungs from expanding normally even after the chyle is removed. The only treatment is to surgically remove the scar tissue using a procedure called decortication, a process fraught with complications if the lungs are diffusely affected. If both lungs must be decorticated, it is common for life-threatening pulmonary edema to occur as the lungs try to re-expand. Sometimes, air leaks out of the lungs and fills the chest with air (pneumothorax). Before opting for any surgical treatment of idiopathic chylothorax, this potential complicating factor should be discussed with the surgeon.

Surgical treatment of chylothorax is something that not all veterinarians are comfortable performing. Discuss with your veterinarian whether referral to a specialist would be best for you and your pet.

Vasculitis is an inflammatory process of the blood vessels (arteries, veins, or capillaries). Cutaneous means the skin is affected. When skin blood vessels are inflamed, this is called cutaneous vasculitis. Weakened or narrowed vessels, and sometimes blood clots, decrease the flow of oxygen and nutrients to the skin. Cutaneous vasculitis is uncommon in dogs and cats.

What Does Cutaneous Vasculitis Look Like?

Signs of cutaneous vasculitis depend on the size and location of the affected blood vessels. Early cases may have only hair loss. Other signs of cutaneous vasculitis include redness, swelling, sores, and bleeding. A dog or cat with cutaneous vasculitis may only have skin changes or may also have other signs such as decreased appetite, lethargy, or fever.

Cutaneous vasculitis can cause skin changes in one place or over most of the body. Ears, tail tips, and paw pads are common sites. When a dog or cat’s ear flap (pinna) is involved, this is called pinnal vasculitis. One or both ears may have hair loss, crusts, and bleeding. When vasculitis affects a dog’s tail, tail wagging can knock scabs from the tail tip and cause bleeding. Severe cases of cutaneous vasculitis on the paw pads can lead to bleeding wounds (ulcers) in the center of the paw pads, making it painful for the dog or cat to walk. Because blood vessels in the ears and tail are small, pinnal, and tail tip vasculitis can lead to a severe block in blood flow. Parts of the ear and tail can then die off (necrosis) and appear black.

How is Cutaneous Vasculitis Diagnosed?

For this reason, the veterinarian may also perform one or more of the following tests:

• Blood tests
• Urine tests
• X-rays
• Ultrasound, a noninvasive test that uses sound waves to take pictures of the body
• Skin biopsy, a test in which a small piece of skin is removed through minor skin surgery, and the blood vessels are examined under a microscope by a veterinary pathologist.

Your pet may also be referred to a veterinary dermatologist, a veterinarian who specializes in ear and skin diseases, to determine if a biopsy is necessary and for additional care.

What Causes Cutaneous Vasculitis?

Although we don’t know why vasculitis happens, sometimes vasculitis follows an infection. It may also be the result of medications, vaccinations, or food. Although frostbite can occur on the ear flaps of dogs and cats, frostbite is a different condition. Cold weather is not a common cause of cutaneous vasculitis. Sometimes, a specific cause of vasculitis cannot be determined (idiopathic).

What is the Long-term Prognosis for Cutaneous Vasculitis?

This depends on the type of cutaneous vasculitis and, sometimes, how quickly the vasculitis was diagnosed and treated. Lesions may come and go, especially as medications are adjusted. If your dog or cat continues to develop new signs of cutaneous vasculitis when medications are decreased, you may need to treat them for the rest of their lives.

The skin on the ears that has already died off (necrosis) will not grow back. Instead, there will be a scar, and part of the ear will remain missing. However, many medications can be used to manage vasculitis and prevent more damage to the skin. Diagnosing and treating the cause of the cutaneous vasculitis with your pet’s veterinarian can also make this disease easier to manage.

We advise people who are concerned about exposure risk, precautions and latest news to consult the CDC informatiion and the Worms and Germs blog, as they are expected to contain the most up-to-date information.

Can SARS-CoV-2 infect dogs, cats and other animals? (updated 11/30)

We don’t really know.  Preliminary evidence suggests that one dog in Hong Kong that lived with a person infected with the virus tested positive multiple times over multiple days.  This suggests that the dog was in fact infected, rather than just contaminated with the virus.  Subsequently, a second dog tested positive by RT-PCR.  Neither dog showed clinical signs (the first dog died after quarantine from causes unrelated to the virus).  In mid-March, 2020, the World Health Organization stated that there is no evidence at present that dogs and cats can be infected with SARS-CoV-2, develop the disease, or spread the disease.  It is important to note that SARS-CoV-2 was not isolated from the first dog in Hong Kong – only RNA was identified via RT-PCR, although subsequent serological testing identified antibodies in the dog’s blood confirming infection.

In late March 2020, a cat living with an infected person in Belgium tested positive for SARS-CoV-2 virus.  The viral RNA was identified in the cat’s feces.  A second cat tested positive in Hong Kong via RTPCR on March 31 2020, with viral RNA identified from oral, nasal and rectal samples.  The first cat showed vomiting, diarrhea and respiratory signs.  The second cat showed no clinical signs.  

Ferrets have been infected experimentally, and variably showed clinical signs of fever, decreased activity and some coughing.  Multiple studies have shown that mink can become infected and transmit this infection to humans.  In Denmark, multiple cases of infection in people were associated with mink farming, leading to en masse culling of mink in that country. Subsequently, mink farms in at least 6 countries, including the US, have identified SARS-CoV-2 in their animals.    

SARS-CoV-2 utilizes two receptors in humans: It binds Angiotensin-Converting Enzyme 2 (ACE2) and then fuses with the cell membrane with help from a type-II transmembrane serine protease (TMPRSS2) (similar to the original SARS virus in the early 2000s).  Sequence homology for ACE2 at the critical binding sites suggests that SARS-CoV-2 might be able to bind to ACE2 receptors in cats and ferrets.  Given the findings from the one dog in Hong Kong (see Worms-and-Germs Blog), we can reasonably suspect that dogs might also bind the virus.  Rats and mice appear not to be able to bind the virus, because their ACE2 receptors are different enough from those of dogs or cats.

Infection, however, requires additional steps than just virus binding and membrane fusion.  Viral replication, avoiding the host immune response etc. are also necessary components of infection and potential transmission.

Can infected dogs and cats transmit the disease to people? (updated 11/30)

This is changing.  Although no transmission from animal to human has been documented, a new study found that ferrets and cats (but not dogs) could be infected, and infected cats could transmit virus to other cats (transmission between ferrets was not tested).  Experimentally infected dogs developed antibodies and viral RNA (but not live virus) was detected in feces from the infected dogs.  Uninfected dogs did not appear to become infected. Subsequent studies have shown that cats can be infected and transmit virus to each other (Halfmann et al 2020), but they did not investigate transmission to people or other non-human animals.  A study from Wuhan found that multiple cats in an epidemiological study had detectable virus, or antibodies suggestive of prior infection. Cats with the highest virus load shared households with infected people.  

To date, all transmission has been human-to-human, after the initial jump from bats (most likely) to humans.  It is worth noting that the original SARS virus could also bind to the dog and cat ACE2 receptor, but no reported cases of pet-to-human transmission of that virus were ever reported, although that outbreak was much smaller and investigation of domestic animals was limited.  Evidence suggests that mink might, however, serve as s reservoir for the virus and possibly transmit it to humans (see previous section).

Consequently, caution should be taken when handling pets of people who are known to be infected, especially cats or ferrets.  Precautions should be also adopted when handling dogs of infected people, however, the risk with dogs transmitting infection to humans appears, for the moment, lower than it might be with cats or ferrets.

What about your pets when you have COVID-19? (new 4/3)

In a household with a person with COVID-19, the infected person poses the greatest risk to others in the household. However, some emerging data suggest that certain pets can get infected, and might be able to transmit the infection (this has not yet been confirmed). Even uninfected pets could track the virus out of the household on their coats, although this risk is considered to be much smaller than people disseminating the virus. Therefore, it makes sense to take simple steps to reduce exposure of pets and keep exposed pets away from others.

The goal is to keep exposed animals away from unexposed people. We now know that cats and ferrets can likely become infected, and can produce live virus that could infect other cats, ferrets or, potentially, people.  We know that dogs can become infected, but they might not be able to infect others (we don’t have evidence of that yet).  We suspect that pigs might not capable of being infected, but additional studies are necessary to confirm this (so all you mini-pig owners – don’t hug your minipigs just yet!).

As we’ve said all along, if you’re sick, stay away from your animals just like you would other people. However, if you have COVID-19 and have been around your pets, keep the pets inside and away from other people (even others in your family who do not have the infection).  If you’re self-isolating, so is your dog/cat/ferret! If you are positive for COVID-19, and your dog/cat/ferret has been snuggling up with you, there is a reasonable chance that the pet is positive. Dogs and cats probably will not show signs although ferrets might show mild signs.  The pet should not come into contact with uninfected household members (unless this is unavoidable – see below).

If possible, your dog should be walked by the infected person.  They should be walked only in an enclosed space (e.g. your yard but away from neighboring dogs) and only for the purposes of elimination (peeing and pooping).  Walks for exercise are out until the person recovers and is no longer shedding virus (tests negative). If the infected person is too sick to do this, other household members should take out the dog isolated with the infected person.  If one or more of the household members have recovered from the infection, they should do it – they’re likely immune to reinfection. 

If no recovered people are available, and the infected person is too sick, then nominate a household member to do the pet care.  The dog should remain isolated with the sick person, not roam free through the house.  The person responsible for letting the dog out should wear gloves (and not let the dog lick their hands/face, etc). You do NOT need to wear disposable gloves.  Dish-washing gloves are fine.  Whoever takes the dog out should carefully wash the gloves (or use rubbing alcohol to clean them) and then wash their hands for at least 20 seconds after removing the gloves upon returning from outside and returning the dog to the isolation area where the infected person is. The risk of transmission from a dog leash is low because the dog is unlikely to have secreted virus onto it, unless it’s a leash chewer – then you’ll want to wash it or disinfect it.  Dog bowls should be cleaned periodically with detergent and water, after which, hands should be washed or disinfected (remember, pet mouths go into the bowl, and pet mouths can carry infected saliva).  Do not touch or handle the bowl while dispensing food; if you do, wash your hands right away.

Ferrets and cats are our main focus, both in terms of keeping infected people away from them (so the animals don’t get infected) and, again, keeping exposed animals away from unexposed people.  The fomite risk is pretty small, although with cats self-grooming, there has to be a greater risk of viral contamination of the fur than in dogs.  Therefore, if uninfected, do not handle the cat if it can be avoided – let the infected person medicate, feed and water the cat if at all possible.

If an uninfected person must take care of a potentially infected (i.e. exposed) cat or ferret, the person should wear gloves while handling the cat, the food and water bowls, litter boxes and ferret condos. Avoid touching the cat or ferret.  Again, kitchen gloves are fine; wash them thoroughly after you’re done as described above, then wash or disinfect your hands.

While these precautions will not guarantee protection against infection, they should hopefully reduce the risk. 

Again, the best solution is to avoid having the pet come into contact with an exposed or infected individual who is self-isolating.

Additional views on this can be found here.

Can pets serve as fomites in the spread of COVID-19?

(A fomite is an object such as a dish or a doorknob that may be contaminated with infectious organisms and serve in their transmission. Answer from the American Veterinary Medical Association)

This question has been addressed by the AVMA. Here is the direct quotation:

“COVID-19 appears to be primarily transmitted by contact with an infected person’s bodily secretions, such as saliva or mucus droplets in a cough or sneeze.COVID-19 might be able to be transmitted by touching a contaminated surface or object (i.e., a fomite) and then touching the mouth, nose, or possibly eyes, but this appears to be a secondary route. Smooth (non-porous) surfaces (e.g., countertops, door-knobs) transmit viruses better than porous materials (e.g., paper money, pet fur), because porous, and especially fibrous, materials absorb and trap the pathogen (virus), making it harder to contract through simple touch.

Because most pet hair is porous and also fibrous, it is very unlikely that a person would contract COVID-19 by petting or playing with a pet. However, because animals can spread other diseases to people and people can also spread diseases to animals, it’s always a good idea to wash hands before and after interacting with animals; ensure the pet is kept well-groomed; and regularly clean the pet’s food and water bowls, bedding material, and toys.”

Could the SARS-CoV-2 virus cause clinical disease in dogs, cats or ferrets?

We don’t know.  The two dogs that might be infected in Hong Kong showed no clinical signs.  The closely related SARS virus did not cause disease in cats (but cats were able to transmit the virus to other cats). In contrast, disease did occur in experimentally infected ferrets. There is currently no evidence that domestic animals can develop disease from this virus or, if infected, transmit it to other animals or people. However, study of animals to date has been limited.

COVID and The Bronx Tiger – what does this mean? (new 4/6)

As we have noted, cats appear to be susceptible to infection with SARS-CoV-2.  They might also be able to transmit the disease from one cat to another.  Because lions and tigers are cats, it’s not surprising that they are also able to be infected.

What this case shows is that people who are asymptomatic or presymptomatic (as was the zoo keeper) can infect others.  That includes cats.

So, can cats infect us?  Currently, there are no reported cases of cats (or dogs or ferrets or tigers) transmitting the virus to humans. How would a cat, living indoors, get infected?  From an infected house member.  And that house member would pose a greater risk to uninfected house members than the cat would. 

What about the cat that is indoor-outdoor?  It’s much harder to enforce a neighborhood wanderer to practice social distancing. Therefore, it might be reasonable to keep a cat like this indoors for the near future.

However, it would be reasonable to suspect that an infected cat might be able to infect a human.  Therefore, if a cat lives with a person who is infected, the cat should be treated as potentially infective – uninfected people should not handle the cat, or if they have to, they should handle the cat while wearing gloves and then wash their hands or disinfect their hands immediately.  Given that cats groom themselves, consider that a potentially infected cat is likely to have virus on its coat.

If there is a cat who has not been near the infected person, keeping that cat separated from the infected person should be sufficient to prevent the cat from becoming infected.

Should I (can I) test a pet for SARS-CoV-2?

Many animal diagnostic laboratories are not currently set up to test for this specific coronavirus.  Some are, and might be able to test animals with known exposure.  For example, if the owner is infected (confirmed), it could be possible for them to ask for testing of their pet dog or cat (or ferret).  However, given that the current data suggest that these pets are not infective to people, the rational for doing this is questionable.

The dilemma about testing pets increases, given that any owner with a known infection (has tested positive) should be quarantined, and their pet should be considered, from a health-and-safety perspective to also be contaminated or infected.  Consequently, you would be required to adopt precautions to prevent infection, by wearing PPE, a face mask, and face shield (to prevent contact from the pet’s contaminated haircoat, or, if infected, saliva or droplets getting into your conjunctival mucosa) etc.  Most clinicians are not set up to do this.

What disinfectants can I use to decontaminate surfaces?

The CDC has provided information for the public about decontaminating and disinfecting surfaces.

A group of German investigators has identified several commonly available disinfectants that should inactivate SARS-CoV-2. These include:

• Isopropyl alcohol (70%), commonly called rubbing alcohol
• Bleach can be diluted by putting 4 teaspoons of bleach per 1 quart of water or 20 milliliters of bleach into 1 liter of water
• 0.5% hydrogen peroxide
• 0.1% sodium hypochlorite

Can ivermectin prevent infection or reduce viral load? (updated 4/7)

Suggested that ivermectin could reduce viral load in vitro. This immediately generated excitement and interest in the idea that ivermectin could be used to either prevent or treat the infection. That’s patently untrue. The study does not provide the doses of ivermectin used to inhibit replication; however, examination of the figures suggests that a concentration of approximately 7 uM was required to effectively suppress viral replication. You would have to give over 100 times that dose – which would likely be fatal to most animal species – to even come close to the concentrations used in the study. That amount is approximately 6,000 monthly doses of the large-dog size ivermectin-based heartworm preventive.

---

Can a veterinary client-patient relationship be established via a telemedicine consultation to minimize exposure risk but still provide veterinary care?

A veterinary client-patient relationship (VCPR) is established primarily by state law. On the Federal front, the FDA has issued guidance noting that due to the current pandemic they “may” not prosecute for extralabel drug use in animals where VCPR doesn’t exist, but this limited potential exception does not change state law. As a general rule, you cannot establish VCPR using telemedicine. On the other hand, once you have VCPR using traditional standards, you can certainly use telemedicine for ongoing care. Regardless, remember you are responsible for meeting the medical standard of care – using telemedicine does not change the standards.

Can I still go to the veterinarian if I am sick?

It’s best if you self-quarantine. The CDC says that If you have a medical appointment, call the healthcare provider and tell them that you have or may have COVID-19. This will help the healthcare provider’s office take steps to keep other people from getting infected or exposed. Perhaps someone else can take your pet in. 

For everyone’s safety, if you believe you have been exposed to COVID-19, call your veterinarian before having your pet seen for any health conditions. Practice social distancing. You and your veterinarian can discuss the safest approach for all concerned whether he needs immediate medical intervention or not. Prescriptions can be mailed, but make sure you call early enough so that they will arrive in the mail by the time you need them.