Current status of dengue and chikungunya in India.

Dengue, a Flavivirus and chikungunya, an Alphavirus, transmitted by Aedes mosquitoes, are a cause of great concern to public health in India. Every year, thousands of individuals are affected and contribute to the burden of health care. Dengue outbreaks have continued since the 1950s but severity of disease has increased in the last two decades. Chikungunya outbreaks started in the 1960s and dwindled to sporadic cases until a resurgence in 2006. Based on the data of National Vector Borne Disease Control Programme (NVBDCP), the number of cases reported in 2013 was about 74 454 for dengue with 167 deaths and 18 639 for chikungunya. The number of cases reported is increasing, probably because of the availability of IgM detection kits produced and distributed by National Institute of Virology through NVBDCP and better reporting. In the absence of well-structured epidemiological studies, this review attempts to summarize reports on dengue and chikungunya outbreaks from various regions of India. For dengue, young adults are the major group affected; the severity of disease in India is still lower than that reported elsewhere in South-East Asia; and paediatric cases of dengue haemorrhagic fever have a high mortality. For chikungunya, all age groups are affected but severe manifestations are more often seen in children. Persisting arthralgia, neurological syndromes and non-neurological manifestations are recorded. Changes in the genotype and mutations in the genome have been detected for both dengue and chikungunya viruses. The review ends with a short summary of the most recent vector-control studies.