Experimental toxoplasmosis in pheasants (Phasianus colchicus)

Area of Science:

• Veterinary Parasitology
• Avian Health
• Infectious Diseases

Background:

• Toxoplasma gondii is an opportunistic parasite with a wide host range.
• Avian species can act as reservoirs or intermediate hosts for T. gondii.
• Understanding T. gondii pathogenesis in game birds like pheasants is crucial for disease management.

Purpose of the Study:

• To evaluate the pathogenicity and infectivity of two different Toxoplasma gondii strains (ME 49 and GT-1) in ring-necked pheasants.
• To compare the diagnostic efficacy of the modified agglutination test (MAT) with other serological assays.

Main Methods:

• Oral inoculation of pheasants with varying doses of T. gondii oocysts (ME 49 and GT-1 strains).
• Clinical observation, necropsy, histological examination, and parasite isolation via bioassay.
• Serological testing using modified agglutination test (MAT), indirect hemagglutination, latex agglutination, and Sabin-Feldman dye test.

Main Results:

• The GT-1 strain caused clinical signs and mortality in one pheasant, with significant lesions in the brain, heart, and intestines.
• T. gondii was successfully isolated from tissues of pheasants infected with both strains, indicating systemic infection.
• All infected pheasants developed high antibody titers detected by MAT, which showed higher sensitivity than other tested serological methods.

Conclusions:

• Ring-necked pheasants exhibit differential susceptibility to T. gondii strains, with GT-1 being more virulent.
• The modified agglutination test (MAT) is a sensitive method for detecting T. gondii antibodies in pheasants.
• Pheasants can serve as hosts for T. gondii, with potential implications for parasite transmission.