Anthropophilic Behavior of Aedes albopictus: A Predominant Vector of Dengue/Chikungunya in Thiruvananthapuram district, Kerala, South India

Human host seeking behavior of Aedes albopictus was evaluated using human landing collections conducted during both dry and wet seasons of 2010-2012 in Thiruvanathapuram district, Kerala. Collections were segregated hourly to provide a time distribution of host-seeking behavior. Aedes albopictus’ day time landing collections comprised of 36.89% and maintained 3-4 per man hour (PMH) density during morning hours whereas 2-3 per man hour density during afternoon hours. PMH density of Aedes albopictus (P < 0.001) and Aedes vittatus (P < 0.05) varied significantly between pre and post monsoon seasons. PMH density of Aedes albopictus is correlated with humidity at pre monsoon season (r = 0.64) but slightly correlated with post monsoon season (r = 0.35). Night time collections showed the presence of Ae. albopictus and Ae. vittatus from both indoor and outdoor landing collections. Density of both Ae. albopictus and Ae. vittatus significantly varied in Day time and Indoor (Night time) collections (P < 0.05). Density of Aedes albopictus significantly varied in Day time and Thinnai (Night time) collections (P < 0.05). Aedes albopictus was the only species that varied both in Indoor and Thinnai night time collections (P < 0.05). This study revealed that the Ae. albopictus mosquitoes predominantly bite during day time (95.5%) compared to night time in Thinnai (3.9%). Increase in dengue cases reported during the post monsoon period in Kerala was due to the increased human host seeking behavior (71.3%) of Ae. albopictus.