NATURAL TRANSOVARIAL TRANSMISSION OF DENGUE VIRUS TYPE 4 BY AEDES AEGYPTI IN BRAZIL
Transovarial transmission; dengue virus type 4; Aedes aegypti; Brazil
In this study, we investigated whether there was transovarial transmission of dengue virus in Aedes aegypti and Aedes albopictus in Natal, Rio Grande do Norte, Brazil. Mosquito larvae were sampled monthly from April 2011 to March 2012. Viral RNA was extracted from 140 µL original suspension of mosquito larvae by the QIAamp Viral RNA Mini Kit and RT-PCR for detecting and typing DENV was performed. During the study period, 1,333 larvae were collected—1,186 (89%) Ae. aegypti and 147 (11%) Ae. albopictus. Dengue virus type 4 was identified in 4 pools of Aedes aegypti larvae in four districts of Natal, Brazil. DENV infection rate in Ae. aegypti larvae was expressed as minimum infection rate (MIR=3.37). Dengue viruses were not identified in Aedes albopictus larvae. This finding further confirms the importance of larval control since the immature stages may become the reservoir of the virus during the inter-epidemic periods as well as the main reservoir of the virus.