title: First evidence of dengue virus infection in wild caught mosquitoes during an outbreak in Assam, Northeast India.
abstract: OBJECTIVE
  Dengue is one of the major public health problems worldwide, transmitted mainly by Aedes aegypti and Ae. albopictus mosquitoes. Rapid urbanisation and industrialisation have led to an increase in vector population in Northeastern states of India. In 2013, Guwahati, the capital city of Assam, India experienced an outbreak of dengue. This study was undertaken with an objective to determine infection rates of dengue viruses (DENV) in both the established vectors present in this region.
  
  
  METHODS
  During the outbreak (2013), adults and larvae of both the vector species were collected from different container habitats found in case reporting areas and container index was also recorded. The mosquitoes were first pooled, homogenised and processed for NS1-ELISA. This was followed by RT-PCR of the mosquito pools.
  
  
  RESULTS
  Both Ae. aegypti and Ae. albopictus were found breeding in containers with container index in the range of 29.41 to 80%. Six pools of Ae. aegypti were found to be positive for NS1 antigen. RT-PCR assay revealed positivity in only the NS1-ELISA positive pools, exhibiting circulation of serotype DENV-2. Minimum infection rate of female and male Ae. aegypti was recorded as 10.87 and 11.03 respectively.
  
  
  CONCLUSIONS
  This is the maiden report of detection of DENV in wild caught Ae. aegypti mosquitoes from Northeastern Region of India. The study also demonstrates the presence of transovarial transmission of dengue virus in this part of country. This information is useful in respect of both entomological as well as epidemiological point of view for taking appropriate vector control measures.
authors.affiliation: Regional Medical Research Centre, NE Region, Dibrugarh, India.
authors.forename: Prafulla
authors.initials: P
authors.lastname: Dutta
authors.forename: Siraj Ahmed
authors.initials: SA
authors.lastname: Khan
authors.forename: Sumi
authors.initials: S
authors.lastname: Chetry
authors.forename: Vas
authors.initials: V
authors.lastname: Dev
authors.forename: Chandra Kanta
authors.initials: CK
authors.lastname: Sarmah
authors.forename: Jagadish
authors.initials: J
authors.lastname: Mahanta
mesh_terms: D000330:Aedes / Q000821:virology*; D000818:Animals; D003715:Dengue / Q000453:epidemiology / Q000635:transmission / Q000821:virology*; D003716:Dengue Virus / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D005260:Female; D007194:India / Q000453:epidemiology; D007303:Insect Vectors / Q000821:virology*; D008297:Male