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Coccidia in the Intestines, Liver[/font]
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By Jeffrey R. Jenkins, DVM
http://www.drexotic.com [/font]
[font="Arial, Helvetica, sans-serif"]We seem to spend a lot of time inthe clinic talking to rabbit owners and referring veterinarians aboutcoccidia. Coccidia are commonly found in rabbits, but only rarely causedisease. As a result they are poorly understood by the rabbit owner,breeder and veterinarian alike. So much so that a local Humane Societyshelter once euthanized all rabbits that were found to have theparasite, not knowing that a majority of normal, healthy rabbits arecarriers. [The shelter has since changed its policy.-Ed.] Findingcoccidia in a fecal parasite examination may not even indicate a needfor therapy. The aim of this article is to give you a betterunderstanding of coccidia. I have included some scientific names forthose who are interested in the more technical end of things. Don't letthem throw you, however, because the underlying message is prettysimple: Prevention depends on keeping rabbits in hygienic conditionsand avoiding infected feces, or food and water contaminated with feces.New rabbits, especially those with an unknown past, should bequarantined for at least 30 days before they are introduced to otherrabbits.[/font]
[font="Arial, Helvetica, sans-serif"]Coccidia are microscopic,one-celled protozoal parasites that affect the intestinal tract andliver of rabbits as well as other animals. Coccidia are the most commonparasites of the rabbit's gastrointestinal tract and a common cause ofillness in young rabbits.[/font]
[font="Arial, Helvetica, sans-serif"]All rabbit coccidia are members ofa single family, Eimeria. There are 12 species of rabbit coccidiareported to infect rabbits, but only a very few of these are importantfrom a disease standpoint and, then, the rabbit's immune system mayhave to be compromised, or two or more species of coccidia present tocreate a disease situation. Therefore, the precise roles of thedifferent species of coccidia in causing disease are not clearlyunderstood. While, the presence of only a few coccidia oocyst (thestage shed in the feces of the rabbit) in a fecal parasite examinationdoes not rule out a diagnosis of coccidiosis, neither does it confirmthe diagnosis, since many healthy rabbits are infected to somedegree.[/font]
[font="Arial, Helvetica, sans-serif"]Only one species, E. stiedae whichparasitizes the liver, is found outside the intestinal tract. E.stiedae may be found in any large groups of rabbits, from rabbitry tofoster home. In mild infections there may be no symptoms or there maybe only mild to moderate retardation of growth, but the disease may befatal, especially in young rabbits. Heavily infected rabbits show signsrelated to the interference of liver function and blockage of bileducts. These rabbits stop eating and become debilitated; eitherdiarrhea or constipation may be noted late in the disease. Occasionallya rabbit's abdomen may be enlarged and the skin may appear to have ayellow coloration. X-rays may show that the liver is enlarged and fluidmay have accumulated in the abdomen. Blood tests will confirm that theliver is damaged and suggest the diagnosis of hepatic (liver)coccidiosis.[/font]
[font="Arial, Helvetica, sans-serif"]Confirmation of the disease isbased on finding oocysts in a fecal or bile samples. Numerous drugshave been used to prevent and treat E. stiedae. The sulfa drugs appearto be the most effective. We recommend sulfamethazine and trimethoprimpotentiated sulfa drugs. All the rabbits in an infected rabbitry orhousehold must be treated until the disease has run its course. Themajor role of these drugs is to control the organism until the rabbits'immunity develops, and immunity resulting from mild infections may belifelong.[/font]
[font="Arial, Helvetica, sans-serif"]The most important species ofintestinal coccidia are E. perforans, E. magna, E. media and E.irresidua, although the exact species involved may not be as importantas the health status of the rabbit. Rabbits become infected byingesting feces containing the coccidia oocyst. This can happen whenthe rabbit cleans its feet or fur that has been contaminated with thefeces of another, infected rabbit. Although rabbits are cecotrophic(eaters of their cecotropes or soft feces), it is generally acceptedthat cecotropes do not contain infectious oocyst. [/font]
[font="Arial, Helvetica, sans-serif"]Clinical signs of intestinalcoccidiosis vary widely depending on the age of the rabbit, theorganism involved, the degree of infection and the relativesusceptibility of the animal (affected by age, stress, diet, etc.).Signs are more often seen in young rabbits with their immature immunesystems. Weight loss, mild intermittent to severe diarrhea which maycontain mucous or blood, and resulting dehydration may be seen. Animalswith severe diarrhea may develop intussusception, a blockage of theintestines caused by a telescoping of the bowel on itself.[/font]
[font="Arial, Helvetica, sans-serif"]Deaths caused by coccidiosis aremost often attributed to dehydration and secondary bacterialinfections. Treatment and prevention of intestinal coccidiosis are asfor hepatic disease. Currently there are no vaccines available againstcoccidiosis.[/font]
[font="Arial, Helvetica, sans-serif"]However, for the rabbit ownerthere is this good news: Many rabbits diagnosed with coccidiosis don'thave coccidia at all! A common mistake made by veterinarians notfamiliar with rabbits is to confuse Cyniclomyces guttulatulus, arabbit-specific Ascosporogenous yeast in the Saccharomyces family andpart of the normal cecal flora of rabbits, with coccidia on fecalexaminations.[/font]
