Coccidiosis is a highly contagious parasitic disease in rabbits with a poor prognosis. It is caused by the protozoan Eimeria. Eimeria is highly host-, organ- and tissue-specific and is generally not infective to humans.

Healthy rabbits may be asymptomatic "carriers." The oocysts are excreted in feces, contaminating the environment, food and water, and can be transmitted to other rabbits, especially young rabbits.

The life cycle of coccidia can be divided into three stages

< p>Asexual reproduction stage: Proliferate by fission reproduction in the epithelial cells of the parasitic site. The merozoites form a large number of merozoites, which rupture the epithelial cells, escape the merozoites, reenter other epithelial cells, and then undergo fission. After repeating this for several generations, a large number of epithelial cells are severely damaged, causing sudden onset of disease.

Sexual reproduction stage: After 2-3 generations of fission reproduction, large and small gametophytes are formed, which reproduce with gametes, forming large gametes (female) and small gametes (male). Male and female gametes combine to form zygotes.

Spore reproductive stage: The zygote quickly forms a capsule and becomes an oocyst. After being excreted in the feces, under suitable temperature conditions, sporangia and sporozoites develop in the oocyst. Eggs containing mature sporozoites The cysts are infectious oocysts.

The presence of coccidia will affect some host cell functions, inhibiting some functions and enhancing some functions. Induced villous atrophy can lead to nutrient malabsorption, electrolyte imbalance, anemia, hypoalbuminemia, and epithelial erosion and ulceration leading to dehydration.

The severity of coccidiosis depends on the number of oocytes ingested. Clinical signs include loss of appetite, depression, abdominal pain, and pale, watery mucous membranes, although these symptoms may not appear in older rabbits. Examination of the stool often reveals blood and strands of mucus. Young rabbits may experience growth retardation due to side effects on the kidneys and liver.

Hematology studies revealed a decrease in hemoglobin and red blood cell count, along with a significant increase in hematocrit and total leukocyte count. Serum analysis showed decreased sodium and chloride levels and increased potassium levels. This electrolyte imbalance can be attributed to diarrhea. Serum calcium, iron, copper, zinc, and glucose are usually slightly lower than in healthy animals, possibly indicating malnutrition due to intestinal damage or secondary bacterial infection. Hepatic coccidiosis is associated with significant increases in serum bilirubin, alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transpeptidase (GGT) .

Intestinal Coccidiosis

Intestinal This form of coccidiosis primarily affects rabbits 6 weeks to 5 months old, but is also seen in older rabbits.

Four to six days after infection, symptoms include rough, dull hair, loss of appetite, dehydration, weight loss, and (severe) diarrhea. If body weight loss reaches 20%, death will occur within 24 hours. This is preceded by convulsions or paralysis. During autopsy, inflammation and edema were found in the ileal and jejunal portions of the intestine. Sometimes accompanied by bleeding and mucosal ulceration.

Hepatic coccidiosis

The hepatic form of coccidiosis affects rabbits of all ages. It is characterized by listlessness, polydipsia, weight loss, and abdominal enlargement. Abdominal X-ray showed enlargement of the liver and gallbladder.

This form of coccidiosis either has a chronic course lasting several weeks or leads to death within 10 days, followed by coma and sometimes diarrhea.

At autopsy, the liver, gallbladder, and bile ducts showed increased swelling. White nodules cover the surface of the liver. Protozoa are found in the liver and bile ducts. A liver smear may reveal the presence of coccidia.

The disease is often accompanied by secondary bacterial infection, especially E. coli infection.

The liver of a healthy rabbit (top) with a rare congenital anomaly of double gallbladders (arrow) and a liver affected by coccidiosis (bottom).

Diagnosis

can be done by identifying oocysts in the stool using the fecal flotation method or by counting the number of coccidia per gram of stool under a microscope. Coccidioidal oocytes may be difficult to distinguish from rabbit-specific yeasts.

Treatment

Treatment of liver coccidiosis is difficult, and the disease may persist throughout life. Anti-coccidiosis treatment is only effective in rabbits 5 to 6 days old. Even if treatment is successful, death and diarrhea may occur.

Drugs used to treat parasites include:

Sulfaquinoxaline: 1 g/liter of water;

Sulfamethazine: 2 g/liter of water.

Toltrazuril, 2.5 to 5 mg/kg (higher doses can cause anorexia).

It is best to treat all rabbits within at least 5 days. Treatment should be repeated after 5 days.

Prevention

Tannin-rich branches and leaves (willow, hazelnut, oak, ash, fruit trees and finally pine) are very effective in preventing coccidiosis.