Xiao L, Herd R P, Rings D M
Department of Veterinary Preventive Medicine, Ohio State University, Columbus 43210.
Vet Parasitol. 1993 Dec;51(1-2):41-8. doi: 10.1016/0304-4017(93)90194-r.
Giardia and Cryptosporidium infections were diagnosed by immunofluorescence assay on two Ohio dairy farms with calf diarrhea problems. On the first farm, all nine diarrheic calves sampled once in June had Giardia cysts in their feces. On the second farm, all five diarrheic calves examined at the beginning of the diarrhea outbreak in March had Giardia infection. When resampled, the overall infection rate of normal and diarrheic calves was 82.4% in April, and 40.0% in August after the diarrhea subsided. Positive calves ranged from 11 to 164 days of age, and 22.2% of them were as young as 1 to 3 weeks of age. Eight of nine diarrheic calves (88.8%) on the first farm had Cryptosporidium infection. Lower infection rates (< 30%) were found on the second farm. Six of 10 positive calves were 11-22 days old, three were 164-177 days old, and one was 71 days old. Five of these 10 positive calves were also positive for Giardia infection. Five diarrheic calves on the northern Ohio farm and one diarrheic calf on the central Ohio farm were treated with metronidazole after failing to respond to antibiotic therapy. Clinical improvement was observed in all calves within 48 h after the start of treatment. The high Giardia infection rates and intensities in calves of a wide age range and the clinical response to metronidazole suggest that Giardia infection contributed to the outbreaks of diarrhea.
在俄亥俄州两个存在犊牛腹泻问题的奶牛场，通过免疫荧光试验诊断出贾第虫和隐孢子虫感染。在第一个农场，6月份采集的所有9头腹泻犊牛的粪便中均发现有贾第虫囊肿。在第二个农场，3月份腹泻暴发初期检查的所有5头腹泻犊牛均感染了贾第虫。再次采样时，4月份正常犊牛和腹泻犊牛的总体感染率为82.4%，腹泻平息后的8月份为40.0%。阳性犊牛的年龄在11至164天之间，其中22.2%的犊牛年龄仅为1至3周。第一个农场的9头腹泻犊牛中有8头（88.8%）感染了隐孢子虫。在第二个农场发现的感染率较低（<30%）。10头阳性犊牛中有6头年龄为11 - 22天，3头为164 - 177天，1头为71天。这10头阳性犊牛中有5头同时也感染了贾第虫。俄亥俄州北部农场的5头腹泻犊牛和俄亥俄州中部农场的1头腹泻犊牛在抗生素治疗无效后接受了甲硝唑治疗。开始治疗后48小时内，所有犊牛均观察到临床症状改善。广泛年龄范围内犊牛的高贾第虫感染率和感染强度以及对甲硝唑的临床反应表明，贾第虫感染导致了腹泻暴发。
