Prevalence of rotaviral infection in diarrheic neonatal calves

Aim: The objective of the current study was to identify the prevalence of rotaviral infection in neonatal calves in Mosul city, Iraq.


Introduction
Screening by ELISA: ELISA was performed to detect rotavirus antigen in the fecal samples as described by Diarrhea is one of the chief causes of calf the kit manufacturer (Rotavirus ELISA kit, Bio-x mortality, morbidity and economic losses in the cattle Diagnostics, Belgium).The net optical density of each industry [1,2].It is known that calves are affected by sample was calculated by subtracting the reading for diarrhoea more at an early stage of the lactation period each sample well from corresponding negative control.Bovine rotavirus is the essential cause of neonatal calf diarrhea.In Iraq rotavirus was detected in faecal samples of calves in Baghdad by using agar gel precipitation test [9] and the virus was isolated from the diarrheic calves [10], Therefore the current study was conducted to throw light on the prevalence of rotavirus among neonatal diarrheic calves and to evaluate the currently used diagnostic tests.

Material and Methods
Animals: During the period from November 2010 to March 2011, a total 220 faecal samples were collected from local neonatal calves (1-30 days old) including, 110 calves suffering from diarrhoea that were randomly selected from field cases in the Mosul city, Iraq, which is about 400 km (250 miles) north-west of In our study, the highest rate of infection was [11,12].The prevalence of rotaviral infection in calves recorded in the diarrheic calves in 8-15 days of age.varies depending on the country and region under study Rotaviruses play a sizable role in the aetiology of [3,13].In previous works there is no published neonatal calf diarrhoea and found in the faeces of information on the epidemiology of rotavirus infection diarrheic calves up to 3rd week of life [3].Calves are in neonatal calves in Mosul city, Iraq.Prevalence of known to excrete the virus through faeces by the rotavirus as the causative agent of neonatal calf diarrhoea secondary infection which continues for 7-8 days and have been reported from many countries including susceptible calves of 2-3 weeks age may get infected 16.8% in Southern Italy [11], 19.4% in Brazil [13], [3, 24].26.4% in Quebec [14] and 8.5% in Turkey [15].The discrepancy between our results and those of other Conclusion studies [11,13,14,15] could be attributed to geogra- The study suggests the role of rotavirus as a phical differences and differences in timing of sample serious cause of neonatal calf diarrhea in Mosul city, collection.
Iraq.Further studies are needed to understand the In the present study, rotavirus antigen was dynamics of rotavirus transmission, cycle, and to detected in only five faecal samples (4.5 %) of 110 nonidentify alternative management practices to minimize diarrheic animals.The occurrence and distribution of the risk to animals.the rotavirus in non diarrheic and clinically normal calves have been previously studied.Rotaviral antigen [3,4].It is a complex multifactorial condition involving Net optical density (O.D) = O.D of specific bindinganimal, environmental, nutritional and infectious agents O.D of non-specific binding [5-8].

Figure- 1 .
Figure-1.Map of Iraq, indicates the Mosul city Baghdad (Figure-1).The climate of the Mosul city is hot, dry at Any sample that yielded a difference of 0.15 or summer and cool rainy at winter.Other samples 110 greater in optical density was considered positive.samples were collected from non diarrheic (clinically Results healthy) animals of similar description from the same locality.Fecal samples were stored at -20 C until Results indicated that 17 out of 110 from diarrheic further processing.calves (15.5 %) and five out of 110 for non-diarrheic animals (4.5%) were found to be positive for rotaviral infection (Table-1).Distribution of antigen positive samples with direct ELISA corresponding to ages were shown in ( Figure-2 ).°www.veterinaryworld.org

Figure- 2 .
Figure-2.Distribution of antigen positive samples of diarrheic animals age-wise