Implementation of guppy fish (Poecilia reticulata), and a novel larvicide (Pyriproxyfen) product (Sumilarv 2MR) for dengue control in Cambodia: A qualitative study of acceptability, sustainability and community engagement

Abstract

In Cambodia dengue vector control activities are focused on larviciding with temephos and pyrethroid based adulticide sprays to which Aedes have been shown to be increasingly resistant. A cluster randomized trial assessed the impact of using biological control tools (guppy fish, pyriproxyfen (PPF), and Communication for Behavioral Impact (COMBI) activities in combination), which would be used in a value comparison to traditional chemical control tools. Given these new intervention methods, a qualitative assessment was designed in order to represent the quality of understanding, acceptance, and implementation by participants. A total of 103 participants in 12 Focus Group Discussions (FGDs) and nine In-Depth Interviews (IDIs) were included in the study. The majority of participants in intervention villages (50 out of 80) preferred guppy fish over other vector control methods due to ease of use and rearing, quick reproduction and propensity to eat larvae. A substantial number of participants (11 out of 40) in intervention villages with PPF favored it due to long-lasting effectiveness, lack of smell and easy maintenance. Participants showed high demand for both interventions and were willing to pay between 100–500 riel (0.03–0.13 USD). Nearly all participants perceived that the interventions resulted in a reduction in Aedes mosquitos (both adults and immatures) and dengue cases. The presence of larvae in the water despite the use of PPF was a source of concern for some participants, although this was overcome in some cases with proper health education through health volunteers. Interpersonal communication through health volunteers was the most favorite method of transmitting prevention messages. The community led COMBI strategy resulted in high acceptance and perceived effectiveness of the interventions in target villages. Health volunteers are an effective and accepted channel of communication to engage communities, disseminate information and promote behavioral change at the household and community level. If shown effective through corresponding entomological surveys, the interventions should be continued and further strengthened to ensure they are accessible, available and affordable. Dengue is one of the most rapidly spreading mosquito-borne viral diseases in the world and is caused by bites of infected Aedes mosquitoes. Dengue infection is a systemic and dynamic disease with a wide clinical spectrum that includes both severe and non-severe manifestations. In some cases dengue can lead to death. Cambodia has one of the highest per-capita incidence rates. Without a cure or routinely available vaccine, dengue control relies largely on reduction and avoidance mosquitoes. In Cambodia dengue mosquito control activities are focused on larviciding with temephos and pyrethroid based adulticide sprays to which Aedes have been shown to be increasingly resistant. The current qualitative study was designed to better understand the community acceptance and perceptions of biological controls that would overcome insecticide resistance for consideration in dengue control strategies for the future. Two control methods were deployed in different size water containers: (1) guppy fish to predate mosquito larvae in large containers, and (2) a slow-release larvicide (pyriproxyfen) product in small containers. A total of 103 people participated in 12 FGDs and nine IDIs. Both methods were generally seen positively. The advantages of guppy fish were their ease of use and rearing, and evident propensity to eat larvae. The advantages of pyriproxyfen was its long-lasting effectiveness, lack of smell, and easy maintenance. Interpersonal communication through health volunteers was the most preferred method of transmitting prevention messages. Both mosquito control interventions should be considered in future projects in Cambodia.