Hamilton C M, Robins R, Thomas R, Oura C, Oliveira S, Villena I, Innes E A, Katzer F, Kelly P J
Moredun Research Institute, Pentlands Science Park, Midlothian, EH26 0PZ, UK.
School of Veterinary Medicine, Ross University, Island Main Road, West Farm, Saint Kitts and Nevis.
Acta Parasitol. 2019 Dec;64(4):738-744. doi: 10.2478/s11686-019-00071-7. Epub 2019 May 20.
Toxoplasma gondii is a zoonotic parasite capable of infecting a wide range of hosts. Free-range chickens are important sentinels in the epidemiology of this parasite as they feed from the ground and are likely to ingest oocysts shed in the faeces of infected cats. Atypical strains of T. gondii are known to dominate in South America where they are associated with more severe disease in humans, yet relatively little is known about the strains circulating in neighbouring Caribbean islands.
In this study, hearts and brains were collected from free-range chickens in Antigua and Barbuda (n = 45), Dominica (n = 76) and Trinidad (n = 41), and DNA was extracted for nested ITS1 PCR and PCR-RFLP. Sera were collected and screened for antibodies using the modified agglutination test (MAT).
Antibodies to T. gondii were detected in 20.5, 38.2 and 17.1% of chickens in Antigua and Barbuda, Dominica and Trinidad, respectively. Toxoplasma gondii DNA was also detected by PCR in 24.4, 17.1 and 17.1% of chickens, respectively, giving an overall prevalence of 31.1, 42.1, and 29.3% for each of the 3 island nations. Results of PCR-RFLP revealed 2 new atypical genotypes (designated ToxoDB #281 and #282) and one Type III (ToxoDB #2) in chickens from Antigua. Partial genotyping of a further 8 isolates (7 from Antigua and one from Trinidad) revealed different allele-types at five or more markers for 7 of the isolates, suggesting atypical genotypes.
This is the first study to report the prevalence of T. gondii in free-range chickens in Antigua and Barbuda, Dominica and Trinidad and Tobago. It is also the first to report the presence of atypical genotypes in Antigua and Barbuda and Trinidad and Tobago.
刚地弓形虫是一种人畜共患寄生虫，能够感染多种宿主。散养鸡是这种寄生虫流行病学中的重要哨兵，因为它们在地面觅食，很可能摄入受感染猫粪便中排出的卵囊。已知弓形虫非典型菌株在南美洲占主导地位，在那里它们与人类更严重的疾病相关，但对于邻近加勒比岛屿上传播的菌株了解相对较少。
在本研究中，从安提瓜和巴布达（n = 45）、多米尼克（n = 76）和特立尼达（n = 41）的散养鸡中采集心脏和大脑，提取DNA用于巢式ITS1 PCR和PCR-RFLP。采集血清并使用改良凝集试验（MAT）筛查抗体。
在安提瓜和巴布达、多米尼克和特立尼达的鸡中，分别有20.5%、38.2%和17.1%检测到抗弓形虫抗体。通过PCR也分别在24.4%、17.1%和17.1%的鸡中检测到弓形虫DNA，这三个岛国的总体患病率分别为31.1%、42.1%和29.3%。PCR-RFLP结果显示，在来自安提瓜的鸡中发现了2种新的非典型基因型（命名为ToxoDB #281和#282）和1种III型（ToxoDB #2）。对另外8个分离株（7个来自安提瓜，1个来自特立尼达）进行的部分基因分型显示，其中7个分离株在5个或更多标记处具有不同的等位基因类型，表明为非典型基因型。
这是第一项报告安提瓜和巴布达、多米尼克以及特立尼达和多巴哥散养鸡中弓形虫患病率的研究。也是第一项报告在安提瓜和巴布达以及特立尼达和多巴哥存在非典型基因型的研究。
