DETECTION AND MOLECULAR CHARACTERISATION OF ROTAVIRUS OF PIGS
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Date
2019-07-15
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COLLEGE OF VETERINARY AND ANIMAL SCIENCES, POOKODE WAYANAD
Abstract
Pig farming is a source of income for small and marginal farmers in Kerala.
One of the important health problems in suckling and recently weaned piglets is
neonatal diarrhoea. Rotaviruses belonging to Group A are one of the most frequently
detected viral agents associated with diarrhoea in swine. Though the incidence of
rotaviruses in Kerala has been established, a thorough study of the agent with respect
to genotypes of the virus has not been carried out. Hence this study was undertaken to
detect the presence of rotavirus in faecal samples of piglets by reverse transcriptase
polymerase chain reaction (RT-PCR) and to genotype the virus by nucleotide
sequencing.
A total of 100 diarrhoeic faecal samples were collected from piglets reared in
organized farms in Wayanad, Kozhikode, Palakkad, Thrissur and Ernakulam districts
of Kerala. All these faecal samples were screened for the presence of porcine
rotavirus (PRV) by RT-PCR. Of the 100 diarrhoeic faecal samples, 12 (12 per cent)
samples was found to be positive for VP6 gene as evidenced by a 309 bp amplicon.
Positive samples were obtained from Palakkad and Wayanad districts only. On
analysis of the nucleic acid sequence of VP6 gene, it was observed that majority of
the viruses were of inner capsid type I5 and one was of I14 type. When the positive
samples were tested by RT - PCR for VP7 and VP4 gene, 10 (83.33 per cent) and 11
(91.66 per cent) samples were positive in the first round RT-PCRs yielding amplicons
of 1062 and 876 bp respectively. When representative samples were tested in the
semi nested PCR for VP7 gene amplicons corresponding to G2, G4, G5, G6 and G9
genotypes were obtained. In the semi nested RT-PCR for VP4 gene, P[6], P[19] and
P21-5 genotypes were detected. Some of the sequences showed close similarity to
rotaviruses isolated from humans and from bovines. Of the G and P types detected,
G2, G9 and P[6] have been reported in humans in Kerala. Hence the results of the
study indicated that the rotaviruses of pigs in Kerala are genetically diverse.