Abstract
Rotavirus is distributed worldwide as an enteric pathogen in man, animal and
poultry. Bovine rotavirus (BRV) has been detected in both dairy and beef cattle
herds worldwide. A total of 200 faecal samples were collected from diarrheic
calves of the dairy region of Barisal, Madaripur and Sirajgonj districts during
the period from January 2014 to October 2015. These 200 faecal samples were
consisted of 68 from Barisal, 92 from Madaripur and 40 from Sirajgonj. The
collected stool samples were screened using rapid test- strips BIO K 152 to
determine the presence of BRV. Group A BRV was detected in 22.50% of faecal
samples (45/200). The highest rate of BRV infection was detected in the Barisal
(26.47%) and Madaripur (26.08%) while the lowest detection rate was in
Sirajgonj (7.5%). BRB was predominantly detected 23.37% - 24.67% in calves at
the age of 1-2 months. Female calves (25%) were more susceptible then male
calves (20%). BRV was highly prevalent in summer (30.35%) followed by winter
(25.71%) and rainy (13.51%) season. The detected positive rotavirus samples by
rapid test- strips BIO K 152 were also examined by polyacrylamide gel
electrophoresis and silver Staining (PAGE-SS) technique for the detection of
presence of rotavirus dsRNA. About 70% of positive rotavirus samples by rapid
test- strips BIO K 152 was found positive in PAGE. All the electropherotypes
were long pattern. RT-PCR and sequencing were applied to determine the
distribution of G and P serotypes of bovine rotaviruses circulating in
Bangladesh. Genotyping analysis of rotavirus (G & P) in 30 positive samples
indicated that G6P [11] was the most prevalent genotype (94.44%) followed by
G10P [11] (5.56 %). Seven samples (23.33%) could not be G and/or
P typed. Phylogenetic study showed that BRV G6 strains are the nearest to
those from Indian strains and BRV G10 strains showed 99.9% identities with
Indian strain. All P [11] strains showed 98-99% identities to each other and also
with Indian strains. No genetic evolution among Bangladeshi and other BRV
strain was found. This study demonstrates that BRV is a contributing pathogen
to diarrhoeal disease in calves of different three district of Bangladesh. In the
present study, it was not investigated that bacteria, parasites or any other
pathogens responsible for causing diarrhea or not.