PIGEON COCCIDIOSIS (EIMERIOSIS)

A conditionally pathogenic disease

Coccidiosis is a parasitic disease specific to all species of mammals and birds. It presents severe clinical forms in young animals and mild or inapparent forms in adults. Coccidiosis is caused by protozoa from the Eimeridae family. Those that infect chickens are not pathogenic to pigeons and vice versa. The most widespread protozoa in pigeons are represented by two species: E. labbena and E. columbarum. Both species affect only pigeons. They appear as oocysts that become infective only after maturing in the external environment.

The disease is common in pigeons, most of which are carriers of coccidia. Coccidiosis usually occurs during seasons with high humidity, when favorable factors are created in the shelter (heat and humidity). It occurs in overcrowded, unhygienic pigeon lofts, with droppings not removed in time or with improperly placed feeders and drinkers, which can be contaminated with oocysts from droppings.

Other predisposing factors for the disease include: unbalanced feed rations quantitatively and qualitatively, nutrient deficiencies in vitamins (A, B complex, vitamins E, K), certain elements (calcium, selenium), or essential amino acids.

Biological cycle

Coccidia have two developmental stages: one in the external environment and another endogenous, within the organism. A sick bird eliminates coccidia eggs (oocysts) through its feces. Under conditions of humidity and heat, these will develop into infective oocysts. Pigeons become contaminated by ingesting them with water or food. Once in the intestine, they release their component elements, which will penetrate the intestinal mucosa, where the second phase of parasite development (endogenous) occurs. The oocyst stage is reached again, and thus the cycle restarts.

Symptoms and evolution

After ingesting oocysts, pigeons develop lesions in the intestinal wall and within 4-7 days begin to excrete oocysts. The disease can evolve in two forms:

• an asymptomatic or subclinical form, which is the most common – in which pigeons ingest small quantities of oocysts and manage to develop immunity. This creates a balance between the host and the parasite;

• an acute form, when pigeons ingest large quantities of oocysts and the disease's progression becomes severe due to the intervention of other stress factors. Pigeons lose weight, develop grey or bloody muco-watery diarrhea, anorexia, thirst, dull, lusterless plumage with a dirty appearance.

The disease evolves in an acute form in squabs and young birds, which become depressed, with ruffled feathers and bluish skin. They do not consume food, drink a lot of water, and have diarrhea, sometimes bloody. All these lead to weight loss, muscle wasting, deviation of the sternal keel, delayed flight, and even death. In adults, the disease's evolution is chronic. Clinical signs are absent or mild, manifested only by weight loss and dull feathers.

Presumptive diagnosis is based on clinical signs, but a definitive diagnosis is made only in the laboratory. Differential diagnosis is made against other diseases with similar clinical and lesional aspects (hypovitaminoses, digestive helminthiasis, trichomoniasis, salmonellosis, enteritis of various etiologies, etc.).

Prevention and treatment

Daily cleaning of shelters and proper ventilation are recommended to prevent humidity. Periodic disinfection of the shelter with specific solutions is mandatory, and if necessary, by flaming. Water and food containers should be cleaned and disinfected daily. Chemoprophylaxis and treatment are carried out with anticoccidial medications based on sulfonamides or oral solutions, amprolium, or with medications containing antibiotics with an anticoccidial role. Preventively and curatively, vitamins must be administered throughout the entire duration of treatment with anticoccidial products. Treatment with sulfonamides must be obligatorily associated with vitamin K3 administered in drinking water.