Kyasanur forest disease (KFD) is a zoonotic
viral disease caused by
infection by a Flavivirus, a member of the family Flaviviridae. KFD is a public health concern in the Karnataka State in southern India. Available conventional diagnostic tests such as virus isolation and serological tests, such as haemagglutination inhibition and
complement fixation tests are time consuming. This study reports the development of a nested RT-PCR [nRT-PCR] and a TaqMan-based real-time RT-PCR and
IgM antibodies capture ELISA [MAC-ELISA] for rapid and accurate diagnosis of suspected KFD cases. The nRT-PCR and the TaqMan-based real-time RT-PCR assays were developed using gene sequences of the
NS-5/non-coding region. Both the assays detected KFD
viral RNA in acute phase human serum samples and can provide early diagnosis of
infection. Real-time RT-PCR was found to be more sensitive than nRT-PCR, which could detect 38 copies of KFDV
RNA. MAC-ELISA was developed for the detection of recent
infections. Although real-time RT-PCR and nRT-PCR require expensive
reagents, expensive equipment and trained personnel, the developed MAC-ELISA can be used easily in the affected areas. These tests add to the existing diagnosis arsenal against haemorrhagic viruses that are prevalent in India. These assays will also help to extend our knowledge of the pathology of KFD virus and its associated clinical features, by measuring the viral titre during
infection and at the time of seroconversion. Information, which is not available currently because of the lack of appropriate diagnostic methods. In addition, early laboratory diagnosis of KFDV
infection will help in the application of appropriate control measures and management of KFD cases.