Pathogenicity of Five Strains of Toxoplasma gondii from Different Animals to Chickens.
Toxoplasma gondii is a protozoan parasite with a broad range of intermediate hosts. Chickens as important food-producing animals can also serve as intermediate hosts. To date, experimental studies on the pathogenicity of T. gondii in broiler chickens were rarely reported. The objective of the present study was to compare the pathogenicity of 5 different T. gondii strains (RH, CN, JS, CAT2, and CAT3) from various host species origin in 10-day-old chickens. Each group of chickens was infected intraperitoneally with 5×10(8), 1×10(8), 1×10(7), and 1×10(6) tachyzoites of the 5 strains, respectively. The negative control group was mockly inoculated with PBS alone. After infection, clinical symptoms and rectal temperatures of all the chickens were checked daily. Dead chickens during acute phage of the infection were checked for T. gondii tachyzoites by microscope, while living cases were checked for T. gondii infection at day 53 post-inoculation (PI) by PCR method. Histopathological sections were used to observe the pathological changes in the dead chickens and the living animals at day 53 PI. No significant differences were found in survival periods, histopathological findings, and clinical symptoms among the chickens infected with the RH, CN, CAT2, and CAT3 strains. Histopathological findings and clinical symptoms of the JS (chicken origin) group were similar to the others. However, average survival times of infected chickens of the JS group inoculated with 5×10(8) and 1×10(8) tachyzoites were 30.0 and 188.4 hr, respectively, significantly shorter than those of the other 4 mammalian isolates. Chickens exposed to 10(8) of T. gondii tachyzoites and higher showed acute signs of toxoplasmosis, and the lesions were relatively more severe than those exposed to lower doses. The results indicated that the pathogenicity of JS strain was comparatively stronger to the chicken, and the pathogenicity was dose-dependent.
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, P. R. China.
Shuai
S
Wang
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, P. R. China.
Guang-Wei
GW
Zhao
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, P. R. China.
Wang
W
Wang
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, P. R. China.
Zhen-Chao
ZC
Zhang
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, P. R. China.
Bo
B
Shen
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, P. R. China.
I A
IA
Hassan
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, P. R. China.
Qing
Q
Xie
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, P. R. China.
Ruo-Feng
RF
Yan
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, P. R. China.
Xiao-Kai
XK
Song
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, P. R. China.
Li-Xin
LX
Xu
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, P. R. China.
Xiang-Rui
XR
Li
D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D002371:Cat Diseases / Q000469:parasitology; D002415:Cats; D002645:Chickens; D011201:Poultry Diseases / Q000097:blood / Q000401:mortality / Q000469:parasitology* / Q000473:pathology; D013552:Swine; D013553:Swine Diseases / Q000469:parasitology; D014122:Toxoplasma / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity* / Q000502:physiology; D014124:Toxoplasmosis, Animal / Q000097:blood / Q000401:mortality / Q000469:parasitology* / Q000473:pathology; D014774:Virulence
D000913:Antibodies, Protozoan
Toxoplasma gondii; chicken; pathogenicity