Campos-da-Silva Danielle R, da Paz Jeanne S, Fortunato Viviane R, Beltrame Marcus A V, Valli Luis C P, Pereira Fausto E L
Graduate Program in Pharmaceutical Sciences, Vila Velha University, Rua Comissário José Dantas de Melo, n°21, Boa Vista, 29102-770, Vila Velha, ES, Brazil.
School of Veterinary Medicine, Vila Velha University, Rua Comissário José Dantas de Melo 21, Boa Vista, 29102-770, Vila Velha, ES, Brazil.
Parasitol Res. 2015 Nov;114(11):4289-93. doi: 10.1007/s00436-015-4669-7. Epub 2015 Aug 29.
Human toxocariasis may be acquired by eating raw chicken liver. However, there are no reports on the prevalence of natural infection of chickens with Toxocara. The aim of this study was to evaluate the presence of anti-Toxocara antibodies as indicators of natural infection with Toxocara, in free-range chickens from Espírito Santo State, Brazil. An ELISA test with secretory and excretory Toxocara canis antigens was used. Negative controls were 20 industrial chickens reared in a high hygiene standard environment. Positive control serum was from a chicken infected with embryonated eggs of T. canis. Sera were adsorbed with Ascaridia galli extract to reduce cross-reactivity. Cut-off was the mean plus four times the standard deviation of optical density (OD) in negative group. One hundred and fifty-seven sera from free-range chicken were investigated. Results showed 58.5% of the chickens were positive with ELISA test; 12.7% had OD over the positive control and may be considered as true infected chickens. The results between the cut-off and the positive control may include infections with low titers of antibodies or may represent serum scar of past infection or may be the result of cross-reaction with other nematodes rather than A. galli which is used for the adsorption of sera. In conclusion, high prevalence of Toxocara sp. antibodies demonstrates natural infection of free-range chickens from Espírito Santo State which may represent a risk of infection with this nematode in people who have the habit of eating raw or undercooked chicken meat or viscera. The results also suggest that chickens may be useful as sentinels to detect soil contaminated with Toxocara eggs.
人体弓蛔虫病可能通过食用生鸡肝而感染。然而，目前尚无关于鸡自然感染弓蛔虫的流行情况的报道。本研究的目的是评估巴西圣埃斯皮里图州散养鸡中抗弓蛔虫抗体的存在情况，以此作为弓蛔虫自然感染的指标。采用了针对犬弓蛔虫分泌排泄抗原的酶联免疫吸附测定（ELISA）试验。阴性对照为20只在高卫生标准环境中饲养的工业化养殖鸡。阳性对照血清来自一只感染了犬弓蛔虫带胚卵的鸡。血清用鸡蛔虫提取物吸附以减少交叉反应。临界值为阴性组光密度（OD）平均值加四倍标准差。对157份散养鸡血清进行了检测。结果显示，ELISA试验中58.5%的鸡呈阳性；12.7%的鸡OD值超过阳性对照，可被视为真正感染的鸡。临界值与阳性对照之间的结果可能包括低滴度抗体感染、可能代表既往感染的血清痕迹，或者可能是与其他线虫而非用于血清吸附的鸡蛔虫发生交叉反应的结果。总之，弓蛔虫属抗体的高流行率表明圣埃斯皮里图州的散养鸡存在自然感染，这可能对有食用生或未煮熟鸡肉或内脏习惯的人构成感染这种线虫的风险。研究结果还表明，鸡可用作检测被弓蛔虫卵污染土壤的哨兵。
