Universidade Federal da Bahia, Escola de Medicina Veterinária, Departamento de Patologia e Clínicas, Avenida Ademar de Barros, 500, Ondina, Salvador, Bahia 40170-110, Brazil.
Vet Parasitol. 2012 Nov 23;190(1-2):74-9. doi: 10.1016/j.vetpar.2012.05.007. Epub 2012 May 19.
The Toxoplasmatinae parasites Toxoplasma gondii, Neospora caninum and Hammondia spp. have carnivores as definitive hosts that shed the parasite oocysts in their feces. Birds that feed directly from the soil, such as chickens, are exposed to infection and may serve as indicators of the presence of the parasite in the environment and as a source of infection for other animals. The aims of this study were to determine the frequency of infection by these parasites in free ranging chickens, to test whether chickens are intermediate hosts of Hammondia spp., and to isolate N. caninum from chickens. One hundred chickens, which were raised in contact to cattle and dogs, were bought in five towns located in Bahia, Brazil. Blood and tissues (brain and heart) were used for serology, molecular tests and bioassay in mice for parasite isolation. T. gondii DNA was detected in 29 chickens, and N. caninum DNA was observed in six animals. Hammondia spp. DNA was not detected in tissues from any chicken. Tissues from eight N. caninum seropositive chickens were bioassayed in interferon-gamma gene knockout mice, but the mice did not become infected; T. gondii was isolated from six of 14 seropositive chickens after bioassay in outbreed Swiss mice. The authors concluded that: chickens seem to be better hosts for T. gondii when compared to N. caninum, based on the molecular and bioassay results; Hammondia spp. probably does not infect chickens or is rarely found in this animal species.
弓形虫科寄生虫刚地弓形虫、新孢子虫和哈氏弓形体属于肉食动物的终末宿主，其粪便中会排出卵囊。直接从土壤中取食的鸟类，如鸡，容易受到感染，它们可能是寄生虫在环境中存在的指示物，也是其他动物感染的来源。本研究的目的是确定自由放养鸡感染这些寄生虫的频率，检测鸡是否为哈氏弓形体的中间宿主，并从鸡中分离新孢子虫。从巴西巴伊亚州的五个城镇购买了 100 只与牛和狗接触饲养的鸡，用于血清学、分子检测和小鼠生物测定以分离寄生虫。在 29 只鸡中检测到刚地弓形虫 DNA，在 6 只动物中观察到新孢子虫 DNA。从任何鸡的组织中均未检测到哈氏弓形体 DNA。将 8 只新孢子虫血清阳性鸡的组织进行干扰素-γ基因敲除小鼠的生物测定，但小鼠未被感染；在对 14 只血清阳性鸡进行瑞士种系小鼠的生物测定后，从其中 6 只鸡中分离出刚地弓形虫。作者得出结论：基于分子和生物测定结果，与新孢子虫相比，鸡似乎更适合作为刚地弓形虫的宿主；哈氏弓形体可能不会感染鸡，或者在这种动物物种中很少发现。
