Dubey J P, Vianna M C B, Sousa S, Canada N, Meireles S, Correia da Costa J M, Marcet P L, Lehmann T, Dardé M L, Thulliez P
U.S. Department of Agriculture, Agricultural Research Service, Animal and Natural Resources Institute, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, Maryland 20705-2350, USA.
J Parasitol. 2006 Feb;92(1):184-6. doi: 10.1645/GE-652R.1.
The prevalence of Toxoplasma gondii in free-ranging chickens is a good indicator of the prevalence of T. gondii oocysts in the soil because chickens feed from the ground. The prevalence of T. gondii in 225 free-range chickens (Gallus domesticus) from Portugal was determined. Antibodies to T. gondii were assayed by the modified agglutination test (MAT) and found in 61 chickens with titers of 1:5 in 8, 1:10 in 6, 1:20 in 3, 1:40 in 23, 1:80 in 5, 1:160 in 4, 1:320 in 8, and 1:640 or higher in 4. Hearts, leg muscles, and brains of 15 seropositive (MAT 1:10 or higher) chickens were bioassayed individually in mice. Tissue from 38 chickens with titers of 1:5 or less were pooled and fed to a T. gondii-free cat. Feces of the cat were examined for oocysts, but none was found. Toxoplasma gondii was isolated from 16 of 19 chickens with MAT titers of 1:10 or higher. Genotyping of 12 of these 16 isolates with polymorphisms at the SAG2 locus indicated that 4 were type III, and 8 were type II. None of the isolates was lethal for mice. Phenotypically, T. gondii isolates from chickens from Portugal were different from those of T. gondii isolates from chickens from Brazil.
散养家禽中弓形虫的流行情况是土壤中弓形虫卵囊流行情况的良好指标，因为家禽在地面觅食。测定了来自葡萄牙的225只散养家禽（家鸡）中弓形虫的流行情况。通过改良凝集试验（MAT）检测弓形虫抗体，发现61只家禽呈阳性，其滴度分别为：8只1:5、6只1:10、3只1:20、23只1:40、5只1:80、4只1:160、8只1:320以及4只1:640或更高。对15只血清学阳性（MAT滴度为1:10或更高）家禽的心脏、腿部肌肉和大脑分别在小鼠体内进行生物测定。将38只滴度为1:5或更低的家禽组织混合后喂给一只无弓形虫的猫。检查猫的粪便中的卵囊，但未发现。从19只MAT滴度为1:10或更高的家禽中的16只分离出了弓形虫。对这16株分离株中的12株在SAG2位点具有多态性的进行基因分型，结果表明4株为III型，8株为II型。所有分离株对小鼠均无致死性。从表型上看，来自葡萄牙家禽的弓形虫分离株与来自巴西家禽的弓形虫分离株不同。
