Cryptosporidiosis occurs worldwide in chickens (broilers), turkeys, quail and ducks. Age resistance in apparent as birds older than 3 weeks are not susceptible.
- Causes of Cryptosporidiosis >
- Effects of Cryptosporidiosis >
- Diagnosis of Cryptosporidiosis >
- Treatment & Control of Cryptosporidiosis >
Causes of Cryptosporidiosis
The life cycle of Cryptosporidium species differ from other Eimeria species. The intracellular stages are confined to the microvillus region of the host cell and the oocysts, which sporulate within the host cells, are infective when releases in the faeces. Two types of oocysts are formed, the thin-walled oocyst rupture to release sporozoites which can penetrate adjacent cells and reinitiate the infection. The thick-walled oocysts pass in the faeces and can transmit infection to other hosts. Also, cryptosporidium can invade the mucosal epithelium of a variety of tissues including the intestines, respiratory tract, cloaca, eyelids and bursa of Fabricius. Cryptosporidum in chickens mainly causes a respiratory disease.
It is common in immunodepressed birds and often seen together with IBD and/or reovirus infections.
Chickens. Cryptosporidum baileyi are small coccidian parasites that do not have sporocytes surrounding the 4 sporozoites. The sporocytes lie naked within the oocyst wall. The life cycle is divided into six major developmental stages: excystation (release of infectious sporozoites, gametogony (formation of male and female gametes), fertilisation (union of gametes), oocyst wall formation (to produce an environmentally resistant form), and sporogony (the formation of infective sporozoites within the oocyst wall).
Effects of Cryptosporidiosis
3-5 day incubation period.Respiratory signs include open mouth breathing, gasping, sneezing and gurgling. Intestinal signs include swelling of the sinuses, diarrhoea, poor weight gain and feed conversion.
Morbidity to 40% and mortality to 10% can occur with the respiratory disease.
Postmortem lesions
Respiratory signs – mucous in the trachea, sinuses, turbinates, thickened frothy exudates in the air sacs, and pneumonia.
Intestinal signs – thickened mucosa lining of middle and lower small intestine, which becomes pale and distended with cloudy mucoid fluid and gas bubbles.
Diagnosis of Cryptosporidiosis
Clinical signs and gross lesions, and the demonstration of life cycle stages associated with lesions in the tissues are diagnostic.
It simulates coccidiosis, yeast, and viral or bacterial respiratory disease.
Treatment & Control of Cryptosporidiosis
The organisms are resistant to most chemical disinfectants. No know treatment exists for controlling this organism.
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