Prevalence and sero-epidemiology of bluetongue with special reference to eastern and north-eastern states of India

Abstract

Abstract Background Bluetongue (BT), an infectious, non-contagious arthropod borne viral disease of domestic and wild ruminants is caused by bluetongue virus (BTV), a type species of Orbivirus genus and Reoviridae family. Albeit bluetongue in India is endemic to southern and western parts, eastern and north-eastern parts of the country didn’t experience any outbreak or reported active disease. Main body of abstract International, national and regional disease statuses including some un-published data were narrated to give a clear picture. Until 1940s, BT was mainly restricted to African countries, however started spearheading to Asian and European countries subsequently. Extensive epidemiological surveys were conducted in central parts of America and Caribbean countries during late 80’s. Massive ingression of BT was observed in northern Europe 2006 onward. In India, although first reported in 1964, BT became endemic in southern states during 1980s and became alarming in late 1990s. A thorough sero-epidemiological study was conducted in different agro-climatic zones of eastern and north-eastern states of India during 2001 to 2017. Sero-epidemiological information of different states had been tabulated. This was the first comprehensive document of BT sero-epidemiology of eastern and north-eastern parts of India. Although BT was not reported officially, sero-epidemiology showed BTV was in circulation in animals and vectors of eastern and north-eastern states of India. Published as also un-published data clearly showed animals and vectors harbor BTV in this part of the country. Short conclusion All the epidemiological components of BT  are present in eastern and north-eastern parts of India that warrants presence of the disease in these parts also. Hence, further surveillance and preparedness  are recommended to avoid future BT outbreak, if any.