Design of a multiplex quantitative reverse transcription-PCR system to simultaneously detect 16 pathogens associated with bovine respiratory and enteric diseases.

AIM: Bovine respiratory disease (BRD) and bovine enteric disease (BED) are two major diseases in cattle, resulting in severe economic losses in the dairy and beef industries. The two major diseases are associated with several factors such as viruses, bacteria, the health condition of the host and environmental factors. We aimed to design a new efficient diagnostic method, which rapidly detect causative pathogens, minimizing economic loss due to BRD and BED. METHODS AND RESULTS: We designed a multiplex quantitative reverse transcription-PCR (qRT-PCR) system for the simultaneous diagnosis of 16 pathogens, including 12 viruses and 4 bacteria related to BRD and BED, based on single qRT-PCR assays in previous studies. The designed multiplex qRT-PCR was highly sensitive and has minimal detection levels which will be no different from those of single qRT-PCR. Moreover, the multiplex qRT-PCR could more efficiently detect the causative pathogens than conventional RT-PCR in test using a part of BRD and BED clinical samples. Furthermore, our data revealed that the multiplex qRT-PCR had high performance in its specificity and reproducibility tests. CONCLUSIONS: Our system can effectively detect multiple BRD or BED related pathogens from each animal while testing several clinical samples via the multiplex qRT-PCR. It is more time-, cost- and labour-efficient than other diagnostic methods. SIGNIFICANCE AND IMPACT OF THE STUDY: Rapid detection of infected animals from the herd using our system will greatly contribute to infection control and prompt treatment in field.

Bovine coronavirus associated syndromes.

Bovine coronaviruses, like other animal coronaviruses, have a predilection for intestinal and respiratory tracts. The viruses responsible for enteric and respiratory symptoms are closely related antigenically and genetically. Only 4 bovine coronavirus isolates have been completely sequenced and thus, the information about the genetics of the virus is still limited. This article reviews the clinical syndromes associated with bovine coronavirus, including pneumonia in calves and adult cattle, calf diarrhea, and winter dysentery; diagnostic methods; prevention using vaccination; and treatment, with adjunctive immunotherapy.