Survival of Betta splendens fish (Regan, 1910) in domestic water containers and its effectiveness in controlling Aedes aegypti larvae (Linnaeus, 1762) in Northeast Brazil

Abstract

Summaryobjective In Northeast Brazil, large domestic containers used to store water are important breeding sites of Aedes aegypti, the main vector of dengue fever. The objective of this study was to estimate the survival of Betta splendens (Perciformes: Osphronemidae) fish in domestic containers in Fortaleza (Ceará State), as well as its effectiveness in the control of premature A. aegypti stages.methods The use of B. splendens was compared to Bacillus thuringiensis israelensis (Bti) in domestic containers. In a first home visit, B. splendens or Bti were applied to water containers. Two follow-up visits were conducted after 3-4 and 5-6 months to assess the presence of viable fish in the containers and infestation by larvae. Betta splendens fish were still present in 97.6% of containers 45-60 days after application. When the fish was present, the infestation rate was significantly higher (P < 0.001) in the Bti group (IR ratio = 21.60; 95% CI: 6.46-72.28). In deposits where the fish remained, efficacy was 85% better than Bti. The permanence of fish was higher in concrete tanks (48.5%) located outside the house (47.5%) and at ground level (53.3%). We conclude that B. splendens may be suitable for biological control of A. aegypti larvae in large domestic water containers, but that appropriate measures should be taken to assure prolonged survival and the presence of fish in the containers.

“Where we put little fish in the water there are no mosquitoes:” a cross-sectional study on biological control of the Aedes aegypti vector in 90 coastal-region communities of Guerrero, Mexico

“…A systematic review of vector control interventions reported effectiveness of biological control approaches [9]. Others have shown the survival of fish in household containers can be adequate with proper care [10]. …”

Efficacy and community effectiveness of larvivorous fish for dengue vector control

“…The studies were published between 1981 and 2012 and were carried out in the following locations: three from Brazil (1,4,8); two each from French Polynesia (5,10) and Taiwan (11,13); and one each from Cambodia (6), China (7), India (3), Mexico (9), Saudi Arabia (12) and Sri Lanka (2). Ten articles were reported in English (2,3,5,6,7,8,9,10,12,13), two in Portuguese (1, 4) and one in Chinese (11).…”

“…Ten articles were reported in English (2,3,5,6,7,8,9,10,12,13), two in Portuguese (1, 4) and one in Chinese (11).…”

“…Of the 13 reports, three were efficacy studies (1,2,3) and the remaining ten were community effectiveness studies (4,5,6,7,8,9,10,11,12,13). One study (7) provided cost data for the different vector control methods used in the study.…”

“…A range of parameters were measured in the community effectiveness studies as follows: breeding sites, the number of breeding sites positive for Aedes larvae, classified into positive or negative breeding sites (5,10); adult mosquito density collected on human bait by aspiration for 15 min per premise (5,7,10); container index (CI), the percentage of water-holding containers infested with larvae (4,6,7,9,11,13); house index (HI), percentage of houses infested with larvae (6, 7); Breteau index (BI), number of positive containers per 100 houses inspected (6,7,13); and infestation rate (IR), incidence rate of larvae in the domestic containers (8,12). However, the entomological sampling procedures used were explained clearly in only five studies (2,5,8,10,12). Additionally, two studies (7, 13) reported on routinely collected epidemiological data.…”