The Camino Verde trial of community mobilisation for control of dengue reported a significant impact on entomological indices of the Aedes aegypti vector , and on serological dengue virus infection and self-reported dengue cases .
One reason for doing r and omised controlled trials ( RCTs ) is that experiments can be convincing .
Early epidemiological experimenters , such as Jenner and the smallpox vaccine and Snow and his famous Broad Street pump h and le , already knew the answer they were demonstrating ; they used the experiments as knowledge translation devices to convince others .
More sophisticated modern experiments include cluster r and omised controlled trials ( C RCTs ) for experiments in the public health setting .
Those who are convinced by a trial and want to act , need to know how the trial relates to their own context , what contributed to success , and what might make it even more effective .
“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
Background In the Mexican state of Guerrero , some households place fish in water storage containers to prevent the development of mosquito larvae . Studies have shown that larvivorous fish reduce larva count in household water containers , but there is a lack of evidence about whether the use of fish is associated with a reduction in dengue virus infection . We used data from the follow up survey of the Camino Verde cluster r and omised controlled trial of community mobilisation to reduce dengue risk to study this association . Methods The survey in 2012 , among 90 clusters in the three coastal regions of Guerrero State , included a question naire to 10,864 households about socio-demographic factors and self-reported cases of dengue illness in the previous year .  Paired saliva sample s provided serological evidence of recent dengue infection among 4856 children aged 3–9 years . An entomological survey in the same households looked for larvae and pupae of Aedes aegypti and recorded presence of fish and temephos in water containers . We examined associations with the two outcomes of recent dengue infection and reported dengue illness in bivariate analysis and then multivariate analysis using generalized linear mixed modelling . Results Some 17 % ( 1730/10,111 ) of households had fish in their water containers . The presence of fish was associated with lower levels of recent dengue virus infection in children aged 3–9 years ( OR 0.64 ; 95 % CI 0.45–0.91 ) , as was living in a rural area ( OR 0.57 ; 95 % CI 0.45–0.71 ) , and being aged 3–5 years ( OR 0.65 ; 95 % CI 0.51–0.83 ) . Factors associated with lower likelihood of self-reported dengue illness were : the presence of fish ( OR 0.79 ; 95 % CI 0.64–0.97 ) , and living in a rural area ( OR 0.74 ; 95 % CI 0.65–0.84 ) . Factors associated with higher likelihood of self-reported dengue illness were : higher education level of the household head ( OR 1.28 ; 95 % CI 1.07–1.52 ) , living in a household with five people or less ( OR 1.33 ; 95 % CI 1.16–1.52 ) and household use of insecticide anti-mosquito products ( OR 1.68 ; 95 % CI 1.47–1.92 ) . Conclusions Our study suggests that fish in water containers may reduce the risk of dengue virus infection and dengue illness . This could be a useful part of interventions to control the Aedes aegypti vector
The Camino Verde trial of community mobilisation for control of dengue reported a significant impact on entomological indices of the Aedes aegypti vector , and on serological dengue virus infection and self-reported dengue cases .
One reason for doing r and omised controlled trials ( RCTs ) is that experiments can be convincing .
Early epidemiological experimenters , such as Jenner and the smallpox vaccine and Snow and his famous Broad Street pump h and le , already knew the answer they were demonstrating ; they used the experiments as knowledge translation devices to convince others .
More sophisticated modern experiments include cluster r and omised controlled trials ( C RCTs ) for experiments in the public health setting .
Those who are convinced by a trial and want to act , need to know how the trial relates to their own context , what contributed to success , and what might make it even more effective .