郑州地区犬隐孢子虫病流行病学调查及动物感染试验

Epidemiological investigation on cryptosporidiosis in dogs in Zhengzhou and experimental infection with oocysts derived from the dogs

用饱和蔗糖溶液漂浮法和改良抗酸染色法对采自犬养殖场、郑州郊区宠物市场、实验动物房、宠物医院以及郑州郊县农村的309份犬粪便样品进行了隐孢子虫感染情况调查,同时用幼犬和SCID小鼠进行了人工感染试验。结果显示,隐孢子虫平均感染率为2.59%（8/309）;犬养殖场、郑州郊县农村和实验动物房犬的隐孢子虫感染率分别为0.56%（1/179）、10.53%（2/19）、16.67%（5/30）,而宠物市场、宠物医院的被调查犬未发现隐孢子虫感染。所查到的8份隐孢子虫阳性样品有6份来自1~3月龄的幼犬,表明幼犬更容易感染隐孢子虫。动物感染试验表明,犬源隐孢子虫不感染SCID小鼠和2月龄非免疫抑制幼犬,但能感染免疫抑制幼犬。组织切片用HE染色观察的结果显示,犬源隐孢子虫主要寄生在幼犬的十二指肠和空肠。根据卵囊形态大小和动物感染试验结果,将从犬分离的隐孢子虫初步鉴定为犬隐孢子虫。

To investigate the prevalence of Cryptosporidium in dogs, 309 fecal samples, which were respectively collected from dog farms, pet markets in the suburban districts of Zhengzhou, laboratory animal rooms, pet hospitals and rural areas of Zhengzhou, were examined by flotation technique using the saturated sucrose solution and the modified acid-fast staining method. In addition, experimental infections with dogderived oocysts in severe combined immunodeficiency（SCID） mice and Cryptosporidium-free puppies were performed. The results showed that the average infection rate was 2.59 %. The dog infection rates on the dog farms,in the suburban districts and the laboratory animal rooms were 0.56%（1/179）, 10.53%（2/19）, 16.67%（5/30） ,respectively. No positive case was found in the dogs from the pet markets and the pet hospitals. Experimental infections demonstrated that the Cryptosporidium oocysts were not able to infect SCID mice and two-month-old non-immunocompetent dogs, but could infect immunosuppressed dogs. Through the tissue slice and the HE staining technique, Cryptosporidia were found in the duodenum and jejunum of the infected dogs. According to the shape of oocysts and the experimental-infection results,the Cryptosporidium oocysts derived from dogs were identified to be Cryptosporidium canis.