Epidemiology of bovine viral diarrhoea among tropical small holder dairy units in Kerala, India

Abstract

Prevalence of bovine viral diarrhoea among 385 dairy cattle reared under a small holder system in Trichur District of Kerala State in India was determined through an ELISA targeting antibodies against p80-p125 non-structural protein of the virus. Prevalence was 24.7% among the total population, but was higher (52%) when 85 animals having infertility problems alone were considered. Significant serum biochemistry differences between animals could be noticed only in total protein, globulin and phosphorous, all of which were low in seropositive animals. All animals which were seronegative for antibodies were screened by another ELISA targeting the E(rns) protein of the viral nucleocapsid to detect persistently infected (PI) animals. The single, positive animal had only a transient period of antigens in the blood, indicating absence of PI animals in the study population. High prevalence of the disease in isolated small holder units even in the absence of PI animals is discussed in view of identifying the common source of infection and initiating control measures.

Seroprevalence of Bovine Viral Diarrhea Virus Infection and Associated Risk Factors in Cattle in Selangor, Malaysia

“…The overall prevalence of BVDV infection obtained from the present study is 33.2% which is a little higher, compared to a report from Saudi Arabia (26%) 8 and Kerala, India (24.7%) 15 but less compared to other places such as Thailand (73%) 14 and Australia (75-85%) varying according to states. 12,13 The finding is also in agreement with previous reports of worldwide BVDV antibody prevalence in cattle ranging from 0-90%.…”

“…The higher prevalence of BVDV in female cattle compared to males might be due to most of the Ladang Angkat farms in this study are dairy farms which depend on imported breeds of cattle such as Jersey and Friesian from disease endemic countries such as India and Brazil with BVDV prevalence of 16.3-24.7% and 56% respectively, 15,19 as well as from neighboring country like Thailand. 20 Australia with high seroprevalence of BVDV as documented by Taylor et al 13 could also be one of the contributing factors as most Jersey cows were imported from there.…”

“…On the other hand, if importation of cattle is from countries like India where BVDV prevalence is relatively lower (15.3-24.7%), it might result in low prevalence of BVDV. 15,19 While farm D, with no detected seropositive animals found, it has been noted that the owner mostly relies on the farm itself to breed and rear its own replacement heifers instead of importation from outside. Trade is known as one of the epidemiological determinants for the introduction and spread of BVDV in cattle herds.…”

“…A total number of 407 animals (87 from Farm A, 36 from Farm B, 15 from Farms C&D each, and 254 from Farm E) were used for blood sampling. Samples from the private farms were obtained randomly based on the total number of animals allowed for bleeding while almost all the animals from farm E were sampled.…”

“…13 Thailand and Argentina have also reported a BVDV prevalence of 73% and 70% respectively, 1,14 while a prevalence of 24.7% is reported recently from smallholder dairy units in India. 15 In Malaysia, despite partially restricted movement of cattle and importation from BVDV endemic countries such as Thailand and Australia, the disease seems to have been overlooked with no investigation and report on BVDV infection in domestic animals so far. Thus, the objectives of this study were to investigate the seroprevalence of the BVDV infection and risk factors in five cattle farms in Selangor, Malaysia.…”