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Study on the species-specificity of Isospora michaelbakeri by experimental infection
1Department of Veterinary Medicine, Veterinary Teaching Hospital, Taiwan, ROC.
Abstract:
Isospora michaelbakeri is one of the Isospora species most commonly found in the wild field, which can cause severe infection and mortality in young sparrows. In this study, we selected I. michaelbakeri (Chung Hsing strain) as a pathogen to orally inoculate russet sparrows (Passer rutilans), spotted munia (Lonchura punctulata), canary (Serinus canaria), Java sparrows (Padda oryzivora), chicken (Gallus domesticus), ducks (Anas platyrhynchos) and BALB/c mice. The results indicated that I. michaelbakeri infected only russet sparrows. Infected sparrows displayed lethargy, muscular weakness and fluffy feathers, followed by rapid death. Liver and spleen enlargement was seen in the infected birds. Schizonts were identified in thin smears from the venous blood, enlarged livers and spleens. Histopathological examination revealed schizonts and merozoites from the liver and spleen of infected russet sparrows, but not from other species experimentally inoculated with I. michaelbakeri in the present study.
Insights
Isospora michaelbakeri causes severe infections and mortality in young sparrows. This study found that only russet sparrows were susceptible to this specific strain of Isospora.
Area of Science:
- Veterinary Parasitology
- Avian Pathology
- Infectious Diseases
Background:
- Isospora species are common in wild birds and can cause significant mortality, particularly in young birds.
- Isospora michaelbakeri is frequently identified in wild populations.
Purpose of the Study:
- To determine the susceptibility of various avian and mammalian species to the Chung Hsing strain of Isospora michaelbakeri.
- To characterize the clinical signs and pathological findings associated with Isospora michaelbakeri infection in susceptible hosts.
Main Methods:
- Oral inoculation of russet sparrows, spotted munia, canary, Java sparrows, chickens, ducks, and BALB/c mice with Isospora michaelbakeri (Chung Hsing strain).
- Clinical observation for signs of infection, including lethargy, weakness, and feather condition.
- Necropsy and histopathological examination of liver and spleen.
- Microscopic identification of schizonts and merozoites in blood smears and tissue samples.
Main Results:
- Only russet sparrows (Passer rutilans) were infected by the Isospora michaelbakeri (Chung Hsing strain).
- Infected russet sparrows exhibited lethargy, muscular weakness, ruffled feathers, rapid death, and enlarged livers and spleens.
- Schizonts and merozoites were identified in the blood, liver, and spleen of infected russet sparrows, but not in other inoculated species.
Conclusions:
- Russet sparrows are highly susceptible to the Isospora michaelbakeri (Chung Hsing strain), experiencing severe clinical disease and mortality.
- Other tested species, including domestic poultry and mice, demonstrated resistance to infection with this specific strain.
- This study highlights the host specificity of Isospora michaelbakeri, with implications for understanding disease dynamics in wild bird populations.
