Using barrier screens to characterize mosquito composition, flight activity, and abdominal status in South Lampung, Indonesia

Abstract

BackgroundMosquito sampling methods target different aspects of mosquito behavior and are subject to trap and location specific biases. The barrier screen sampling method was developed and tested to sample free-flying, blood-fed, and host-seeking mosquitoes. During a pilot study, this method was useful in obtaining an unbiased sample of mosquitoes flying between outdoor larval habitats, and sites where blood meals were obtained. However, a relatively small number of blood-fed Anopheles mosquitoes were collected in Indonesia during the pilot study. The sampling method was extended in South Lampung, Indonesia, to enable the collection of blood-fed mosquitoes. This study aimed to intercept mosquitoes flying between human habitations and larval habitats with a barrier screen and to characterize mosquito composition, flight characteristics (direction, height and time), abdominal status, and parity.ResultsBarrier screens intercepted 15 different mosquito species in South Lampung: eight Anopheles spp. and seven Culex spp. Species compositions varied among the villages in South Lampung. About 15% of Anopheles spp. caught were blood-fed, of which 28.2% of those tested had fed on humans. This is the first time human blood-fed anophelines have been collected in Indonesia using barrier screens. Blood meals identified included cow, dog, goat, and human, as well as mixed blood meals. Activity of unfed An. subpictus, the primary vector collected, flying towards human habitations peaked between 20:00–12:00 h, with a slow decline in activity until 18:00 h. Unfed and fed An. sundaicus, had a different activity profile compared to An. subpictus. Other species demonstrated varied peak activity times, with earlier activity occurring as a general trend. For the Anopheles mosquitoes collected, 55.5% were collected below 0.5 m and 83.9% were captured resting < 1 m from the ground. Parity dissections enabled age structure by species, which revealed species-specific traits such as nulliparous An. subpictus being more active early in the night relative to An. sundaicus.ConclusionsThis study demonstrates that barrier screens are an effective mosquito sampling method that can be used to gain insights into local mosquito species composition, flight characteristics (direction, height and time), abdominal status, and parity.

Anopheles sundaicus complex and the presence of Anopheles epiroticus in Indonesia

“…sundaicus s.l. that exhibited relatively high human-biting rates [53,54] and found infected with malaria sporozoites [53] may actually be An. epiroticus.…”

Resting behaviour of malaria vectors in highland and lowland sites of western Kenya: Implication on malaria vector control measures

“…gambiae (66%, 95% CI: 64-70) was the predominant malaria vector in Bungoma followed by An. funestus (28%, 95% CI: [25][26][27][28][29][30] and An. arabiensis (5%, 95% CI: 4-7).…”

“…It is hypothesized that insecticide-resistant malaria vectors could bite and rest indoors in the presence of interventions whilst susceptible ones bite and rest outdoors. Additionally, behaviors of malaria vectors have been shown to differ on small geographical scales, further complicating malaria elimination efforts [26]. Understanding how the resting habits of malaria vectors change in response to current indoor-based vector control interventions is important for sustaining vector control.…”

Resting behaviour of malaria vectors in a highland and a lowland site of western Kenya: Implication on malaria vector control measures

“…It is hypothesized that insecticide-resistant malaria vectors could bite and rest indoors in the presence of interventions whilst susceptible ones bite and rest outdoors. Additionally, behaviors of malaria vectors have been shown to differ on small geographical scales, further complicating malaria elimination efforts[25]. Understanding how the resting habits of malaria vectors change in response to current indoor-based vector control interventions is important for sustaining vector control.…”