台南市牛隻Babcsia bovis感染之疫學、病理學及分子生物學

Abstract

Bovine babesiosis was uncovered in Tainan city in April, 2005. A total number of 601 2-year-old suspected infected dairy cows in three cattle farms that suffered from fever, loss of appetite, decrease milk production, and hemoglobinuria were found during a large scale of epidemiologic studies of bovine babesiosis by Tainan Hsien Livestock Disease Control Center. Overall, the morbidity and mortality rates were 5.15% (31/601) and 45.1% (14/31), respectively. Based on the results of clinical symptoms, blood smears, pathology examinations, electron microscopy, polymerase chain reaction, and DNA sequencing, these outbreaks were diagnosed as Babesia bovis. In phylogenetic analysis, it was also uncovered that the Taiwanese strain (Babesia bovis) was closely related to South Africa and US strains and their nucleotide sequences exhibited 98.8% identity. Upon diagnosis, the suspected animals were treated with Imizol(superscript ®) and vitamin B, and farm environments of all three farms were disinfected. Polymerase chain reaction (PCRI and commercial indirect immunofluorescent antibody (IFA) test were also used to detect Babesia bovis and the seroprevalence in all three cattle farms from July to October, 2005. The positive rate for B. bovis detected by PCR was low and positive rates for Babesia bovis in July and October by IFA were 9.7%-21% and 24.1%-38.7%, respectively. The mean of anti-babesia antibodies in October was 22%-27% among all investigated farms, suggesting that although latent infections still occurred but bovine babesiosis seemed to be under control. Therefore, frequent disinfections of cattle farms and eradication of infected animals will effectively reduce latent infections and disease spread.