New focus of Kyasanur Forest disease virus activity in a tribal area in Kerala, India, 2014.
BACKGROUND
Kyasanur Forest disease (KFD) is a febrile illness characterized by hemorrhages, and is reported endemic in the Shimoga district in Karnataka state, India. It is caused by the KFD virus (KFDV) of the family Flaviviridae, and is transmitted to monkeys and humans by Haemaphysalis ticks.


RESULTS
We investigated a new focus of KFD among tribals in a reserve forest in Kerala state, India. A suspected case was defined as a person presenting with acute fever, headache, or myalgia. Human sera were collected and tested for KFDV RNA by real-time RT-PCR, RT-nPCR assay, and anti-KFDV IgM and IgG by ELISA. The index case was a tribal woman with febrile illness, severe myalgia, gum bleeding, and hematemesis. Anti-KFDV IgM antibody was detected in acute and convalescent sera of the index case along with IgG in the second serum. None of her family members reported fever. On verbal autopsy, two more fatal cases were identified as probable primary cases. Acute serum from a case in the second cluster was detected positive for KFDV RNA by real time RT-PCR (Ct = 32) and RT-nPCR. Sequences of E gene showed highest similarity of 98.0% with the KFDV W-377 isolate nucleotide and 100% identity with amino acid. Anti-KFDV IgM was detected in the serum of one family member of the index case, as well as in one out of 17 other tribals.


CONCLUSIONS
We confirmed a new focus of KFDV activity among tribals in a reserve forest in the Malappuram district of Kerala, India.
National Institute of Virology (NIV), 20-A, Dr Ambedkar Road, Pune, Maharashtra 411001 India.
Babasaheb V
BV
Tandale
National Institute of Virology Kerala Unit, Alappuzha, Kerala India.
Anukumar
A
Balakrishnan
National Institute of Virology (NIV), 20-A, Dr Ambedkar Road, Pune, Maharashtra 411001 India.
Pragya D
PD
Yadav
Deputy District Medical Officer (Public Health), Malappuram, Kerala India.
Noona
N
Marja
National Institute of Virology (NIV), 20-A, Dr Ambedkar Road, Pune, Maharashtra 411001 India.
Devendra T
DT
Mourya
Arbovirus; Flavivirus; Hemorrhagic fever; India; Kyasanur Forest disease; Ticks