The prevalence of rotavirus in neonatal calf diarrhoea, using electron microscopic examination

Rotavirus is one of the most common causes of diarrhoea in both humans and different animal species. Neonatal calf diarrhoea is a major health problem in calves causing extensive economic losses due to the high mortality rate. Electron microscopy examination is a gold standard diagnostic technique for demonstration of the virus in faeces. This study covers a total of 100 cases of diarrhoeic calves from 25 commercial farms in four districts of East Azerbaijan province, Iran, over a period of 12 months. The objective of this study was to determine the prevalence of rotavirus in neonatal calf diarrhoea. Faecal samples were collected from every calf with clinical diarrhoea. All samples were transferred into a −20°C freezer and under cool conditions, were submitted for virology examination using electron microscopic examination which is a gold standard diagnostic technique for demonstration of the virus in faeces. Data were statistically analysed using Chi-square test. The results of this study showed that rotavirus was present in 34% of cases and a significant difference was found between the prevalence rate and the season (P < 0.05), the highest prevalence was recorded in winter time (48%) and the least during the summer season (16%). Statistically significant difference was also found between the two age groups (P < 0.05); the highest prevalence rate was seen at 2–4 weeks of age (47.61%) and the lowest in the first week (20%). It seems that the presence of a high rate of maternal antibody in colostrum during the first week after parturition can protect the newborn calves against rotavirus.