Utility of entomological indices for predicting transmission of dengue virus: secondary analysis of data from the Camino Verde trial in Mexico and Nicaragua.

Dengue vector entomological indices are widely used to monitor vector density and disease control activities. But the value of these indices as predictors of dengue infection is not established. We used data from the impact assessment of a trial of community mobilization for dengue prevention (Camino Verde) to examine the associations between vector indices and evidence of dengue infection and their value for predicting dengue infection levels. In 150 clusters in Mexico and Nicaragua, two entomological surveys, three months apart, allowed calculation of the mean Container Index, Breteau index, Pupae per Household Index, and Pupae per Container Index across the two surveys. We measured recent dengue virus infection in children, indicated by a doubling of dengue antibodies in paired saliva samples over the three-month period. We examined the associations between each of the vector indices and evidence of dengue infection at household level and at cluster level, accounting for trial intervention status. To examine the predictive value for dengue infection, we constructed receiver operating characteristic (ROC) curves at household and cluster level, considering the four vector indices as continuous variables, and calculated the positive and negative likelihood ratios for different levels of the indices. None of the vector indices was associated with recent dengue infection at household level. The Breteau Index was associated with recent infection at cluster level (Odds ratio 1.36, 95% confidence interval 1.14-1.61). The ROC curve confirmed the weak predictive value for dengue infection of the Breteau Index at cluster level. Other indices showed no predictive value. Conventional vector indices were not useful in predicting dengue infection in Mexico and Nicaragua. The findings are compatible with the idea of sources of infection outside the household which were tackled by community action in the Camino Verde trial.

Cost-effectiveness of community mobilization (Camino Verde) for dengue prevention in Nicaragua and Mexico: A cluster randomized controlled trial.

BACKGROUND: We assessed the cost-effectiveness of Camino Verde, a community-based mobilization strategy to prevent and control dengue and other mosquito-borne diseases. A cluster-randomized controlled trial in Managua, Nicaragua, and in three coastal regions in Guerrero, Mexico (75 intervention and 75 control clusters), Camino Verde used non-governmental community health workers, called brigadistas, to support community mobilization. This donor-funded trial demonstrated reductions of 29.5% (95% confidence interval, CI: 3.8%-55.3%) on dengue infections and 24.7% (CI: 1.8%-51.2%) on self-reported cases. METHODS: We estimated program costs through a micro-costing approach and semi-structured questionnaires. We show results as incremental cost-effectiveness ratios (ICERs) for costs per disability-adjusted life-year (DALYs) averted and conducted probabilistic sensitivity analyses. FINDINGS: The Camino Verde trial spent US$16.72 in Mexico and $7.47 in Nicaragua per person annually. We found an average of 910 (CI: 487-1 353) and 500 (CI: 250-760) dengue cases averted annually per million population in Mexico and Nicaragua, respectively, compared to control communities. The ICER in Mexico was US$29 618 (CI: 13 869-66 898) per DALY averted, or 3.0 times per capita GDP. For Nicaragua, the ICER was US$29 196 (CI: 14294-72181) per DALY averted, or 16.9 times per capita GDP. INTERPRETATION: Camino Verde, as implemented in the research context, was marginally cost-effective in Mexico, and not cost-effective in Nicaragua, from a healthcare sector perspective. Nicaragua's low per capita GDP and the use of grant-funded management personnel weakened the cost-effectiveness results. Achieving efficiencies by incorporating Camino Verde activities into existing public health programs would make Camino Verde cost-effective.

Community cost-benefit discussions that launched the Camino Verde intervention in Nicaragua.

BACKGROUND: Recent literature on community intervention research stresses system change as a condition for durable impact. This involves highly participatory social processes leading to behavioural change. METHODS: Before launching the intervention in the Nicaraguan arm of Camino Verde, a cluster-randomised controlled trial to show that pesticide-free community mobilisation adds effectiveness to conventional dengue controls, we held structured discussions with leaders of intervention communities on costs of dengue illness and dengue control measures taken by both government and households. These discussions were the first step in an effort at Socialising Evidence for Participatory Action (SEPA), a community mobilisation method used successfully in other contexts. Theoretical grounding came from community psychology and behavioural economics. RESULTS: The leaders expressed surprise at how large and unexpected an economic burden dengue places on households. They also acknowledged that large investments of household and government resources to combat dengue have not had the expected results. Many were not ready to see community preventive measures as a substitute for chemical controls but all the leaders approved the formation of "brigades" to promote chemical-free household control efforts in their own communities. CONCLUSIONS: Discussions centred on household budget decisions provide a good entry point for researchers to engage with communities, especially when the evidence showed that current expenditures were providing a poor return. People became motivated not only to search for ways to reduce their costs but also to question the current response to the problem in question. This in turn helped create conditions favourable to community mobilisation for change. TRIAL REGISTRATION: ISRCTN27581154 .

Informed community mobilization for dengue prevention in households with and without a regular water supply: Secondary analysis from the Camino Verde trial in Nicaragua.

BACKGROUND: Studies in different countries have identified irregular water supply as a risk factor for dengue virus transmission. In 2013, Camino Verde, a cluster-randomised controlled trial in Managua, Nicaragua, and Mexico's Guerrero State, demonstrated impact of evidence-based community mobilisation on recent dengue infection and entomological indexes of infestation by Aedes aegypti mosquitoes. This secondary analysis of data from the trial impact survey asks: (1) what is the importance of regular water supply in neighbourhoods with and without the trial intervention and (2) can community interventions like Camino Verde reasonably exclude households with adequate water supply? METHODS: Entomological data collected in the dry season of 2013 in intervention and control communities allow contrasts between households with regular and irregular water supplies. Indicators of entomological risk included the House Index and pupa positive household index. Generalised linear mixed models with cluster as a random effect compared households with and without regular water, and households in intervention and control communities. RESULTS: For the House Index, regular water supply was associated with a protection in both intervention households (OR 0.7, 95%CI 0.6-0.9) and control households (OR 0.6, 95%CI 0.5-0.8). For the pupa positive household index, we found a similar protection from regular water supply in intervention households (OR 0.6, 95%CI 0.4-0.8) and control households (OR 0.7, 95%CI 0.5-0.9). The Camino Verde intervention had a similar impact on House Index in households with regular water supply (OR 0.7, 95%CI 0.5-1.0) and irregular water supply (OR 0.6, 95%CI 0.4-0.8); for the pupa positive household index, the effect of the intervention was very similar in households with regular (OR0.5, 95%CI 0.3-0.8) and irregular (OR 0.5, 95%CI 0.3-0.9) water supply. CONCLUSION: While Aedes aegypti control efforts based on informed community mobilisation had a strong impact on households without a regular water supply, this intervention also impacted entomological indices in households with a regular water supply. These households should not be excluded from community mobilisation efforts to reduce the Aedes aegypti vector. TRIAL REGISTRATION: ISRCTN27581154 .

When communities are really in control: ethical issues surrounding community mobilisation for dengue prevention in Mexico and Nicaragua.

We discuss two ethical issues raised by Camino Verde, a 2011-2012 cluster-randomised controlled trial in Mexico and Nicaragua, that reduced dengue risk though community mobilisation. The issues arise from the approach adopted by the intervention, one called Socialisation of Evidence for Participatory Action. Community volunteer teams informed householders of evidence about dengue, its costs and the life-cycle of Aedes aegypti mosquitoes, while showing them the mosquito larvae in their own water receptacles, without prescribing solutions. Each community responded in an informed manner but on its own terms. The approach involves partnerships with communities, presenting evidence in a way that brings conflicting views and interests to the surface and encourages communities themselves to deal with the resulting tensions.One such tension is that between individual and community rights. This tension can be resolved creatively in concrete day-to-day circumstances provided those seeking to persuade their neighbours to join in efforts to benefit community health do so in an atmosphere of dialogue and with respect for personal autonomy.A second tension arises between researchers' responsibilities for ethical conduct of research and community autonomy in the conduct of an intervention. An ethic of respect for individual and community autonomy must infuse community intervention research from its inception, because as researchers succeed in fostering community self-determination their direct influence in ethical matters diminishes. TRIAL REGISTRATION: ISRCTN 27581154.

The Camino Verde intervention in Nicaragua, 2004-2012.

Camino Verde (the Green Way) is an evidence-based community mobilisation tool for prevention of dengue and other mosquito-borne viral diseases. Its effectiveness was demonstrated in a cluster-randomised controlled trial conducted in 2010-2013 in Nicaragua and Mexico. The Nicaraguan arm of the trial was preceded, from 2004 to 2008, by a feasibility study that provided valuable lessons and trained facilitators for the trial itself. Here, guided by the Template for Intervention Description and Replication (TIDieR), we describe the Camino Verde intervention in Nicaragua, presenting its rationale, its time and location, activities, materials used, the main actors, modes of delivery, how it was tailored to encourage community engagement, modifications made from the feasibility study to the trial itself, and how fidelity to the process originally designed was maintained. We also present information on costs and discuss the place of this study within the literature on implementation science. TRIAL REGISTRATION: ISRCTN27581154 .

Beyond efficacy in water containers: Temephos and household entomological indices in six studies between 2005 and 2013 in Managua, Nicaragua.

BACKGROUND: A cluster-randomized controlled trial of community mobilisation for dengue prevention in Mexico and Nicaragua reported, as a secondary finding, a higher risk of dengue virus infection in households where inspectors found temephos in water containers. Data from control sites in the preceding pilot study and the Nicaragua trial arm provided six time points (2005, 2006, 2007 and 2011, 2012, 2013) to examine potentially protective effects of temephos on entomological indices under every day conditions of the national vector control programme. METHODS: Three household entomological indicators for Aedes aegypti breeding were Household Index, Households with pupae, and Pupae per Person. The primary exposure indicator at the six time points was temephos identified physically during the entomological inspection. A stricter criterion for exposure at four time points included households reporting temephos application during the last 30 days and temephos found on inspection. Using generalized linear mixed modelling with cluster as a random effect and temephos as a potential fixed effect, at each time point we examined possible determinants of lower entomological indicators. RESULTS: Between 2005 and 2013, temephos exposure was not significantly associated with a reduction in any of the three entomological indices, whether or not the exposure indicator included timing of temephos application. In six of 18 multivariate models at the six time points, temephos exposure was associated with higher entomological indices; in these models, we could exclude any protective effect of temephos with 95% confidence. CONCLUSION: Our failure to demonstrate a significant protective association between temephos and entomological indices might be explained by several factors. These include ecological adaptability of the vector, resistance of Aedes to the pesticide, operational deficiencies of vector control programme, or a decrease in preventive actions by households resulting from a false sense of protection fostered by the centralized government programme using chemical agents. Whatever the explanation, the implication is that temephos affords less protection under routine field conditions than expected from its efficacy under experimental conditions. TRIAL REGISTRATION: ISRCTN 27581154 .

Mobilising communities for Aedes aegypti control: the SEPA approach.

Camino Verde (the Green Way) is an evidence-based community mobilisation tool for prevention of dengue and other mosquito-borne viral diseases. Its effectiveness was demonstrated in a cluster-randomised controlled trial conducted in 2010-2013 in Nicaragua and Mexico. The common approach that brought functional consistency to the Camino Verde intervention in both Mexico and Nicaragua is Socialisation of Evidence for Participatory Action (SEPA). In this article, we explain the SEPA concept and its theoretical origins, giving examples of its previous application in different countries and contexts. We describe how the approach was used in the Camino Verde intervention, with details that show commonalities and differences in the application of the approach in Mexico and Nicaragua. We discuss issues of cost, replicability and sustainability, and comment on which components of the intervention were most important to its success. In complex interventions, multiple components act in synergy to produce change. Among key factors in the success of Camino Verde were the use of community volunteers called brigadistas, the house-to-house visits they conducted, the use of evidence derived from the communities themselves, and community ownership of the undertaking. Communities received the intervention by random assignment; dengue was not necessarily their greatest concern. The very nature of the dengue threat dictated many of the actions that needed to be taken at household and neighbourhood levels to control it. But within these parameters, communities exercised a large degree of control over the intervention and displayed considerable ingenuity in the process. TRIAL REGISTRATION: ISRCTN27581154 .

Camino Verde (The Green Way): evidence-based community mobilisation for dengue control in Nicaragua and Mexico: feasibility study and study protocol for a randomised controlled trial.

BACKGROUND: Since the Aedes aegypti mosquitoes that transmit dengue virus can breed in clean water, WHO-endorsed vector control strategies place sachets of organophosphate pesticide, temephos (Abate), in household water storage containers. These and other pesticide-dependent approaches have failed to curb the spread of dengue and multiple dengue virus serotypes continue to spread throughout tropical and subtropical regions worldwide. A feasibility study in Managua, Nicaragua, generated instruments, intervention protocols, training schedules and impact assessment tools for a cluster randomised controlled trial of community-based approaches to vector control comprising an alternative strategy for dengue prevention and control in Nicaragua and Mexico. METHODS/DESIGN: The Camino Verde (Green Way) is a pragmatic parallel group trial of pesticide-free dengue vector control, adding effectiveness to the standard government dengue control. A random sample from the most recent census in three coastal regions of Guerrero state in Mexico will generate 90 study clusters and the equivalent sampling frame in Managua, Nicaragua will generate 60 clusters, making a total of 150 clusters each of 137-140 households. After a baseline study, computer-driven randomisation will allocate to intervention one half of the sites, stratified by country, evidence of recent dengue virus infection in children aged 3-9 years and, in Nicaragua, level of community organisation. Following a common evidence-based education protocol, each cluster will develop and implement its own collective interventions including house-to-house visits, school-based programmes and inter-community visits. After 18 months, a follow-up study will compare dengue history, serological evidence of recent dengue virus infection (via measurement of anti-dengue virus antibodies in saliva samples) and entomological indices between intervention and control sites. DISCUSSION: Our hypothesis is that informed community mobilisation adds effectiveness in controlling dengue. TRIAL REGISTRATION: ISRCTN27581154 .

Introduction and Establishment of Aedes albopictus (Diptera: Culicidae) in Managua, Nicaragua.

Aedes aegypti (L.) is the main vector of dengue virus and more recently chikungunya virus in Latin America. However, the Asian tiger mosquito Aedes albopictus (Skuse, 1894) is expanding its global range and increasing its role in transmission of these diseases. In this report, we suggest that Ae. albopictus was introduced to the Department of Managua, Nicaragua, in 2010 via two independent routes and demonstrate its dissemination and establishment in urban neighborhoods by 2012. The coexistence of two competent vector species could alter the epidemiology of dengue and chikungunya as well as indicate the need for new strategies aimed at vector control.

Evidence based community mobilization for dengue prevention in Nicaragua and Mexico (Camino Verde, the Green Way): cluster randomized controlled trial.

OBJECTIVE: To test whether community mobilization adds effectiveness to conventional dengue control. DESIGN: Pragmatic open label parallel group cluster randomized controlled trial. Those assessing the outcomes and analyzing the data were blinded to group assignment. Centralized computerized randomization after the baseline study allocated half the sites to intervention, stratified by country, evidence of recent dengue virus infection in children aged 3-9, and vector indices. SETTING: Random sample of communities in Managua, capital of Nicaragua, and three coastal regions in Guerrero State in the south of Mexico. PARTICIPANTS: Residents in a random sample of census enumeration areas across both countries: 75 intervention and 75 control clusters (about 140 households each) were randomized and analyzed (60 clusters in Nicaragua and 90 in Mexico), including 85,182 residents in 18,838 households. INTERVENTIONS: A community mobilization protocol began with community discussion of baseline results. Each intervention cluster adapted the basic intervention-chemical-free prevention of mosquito reproduction-to its own circumstances. All clusters continued the government run dengue control program. MAIN OUTCOME MEASURES: Primary outcomes per protocol were self reported cases of dengue, serological evidence of recent dengue virus infection, and conventional entomological indices (house index: households with larvae or pupae/households examined; container index: containers with larvae or pupae/containers examined; Breteau index: containers with larvae or pupae/households examined; and pupae per person: pupae found/number of residents). Per protocol secondary analysis examined the effect of Camino Verde in the context of temephos use. RESULTS: With cluster as the unit of analysis, serological evidence from intervention sites showed a lower risk of infection with dengue virus in children (relative risk reduction 29.5%, 95% confidence interval 3.8% to 55.3%), fewer reports of dengue illness (24.7%, 1.8% to 51.2%), fewer houses with larvae or pupae among houses visited (house index) (44.1%, 13.6% to 74.7%), fewer containers with larvae or pupae among containers examined (container index) (36.7%, 24.5% to 44.8%), fewer containers with larvae or pupae among houses visited (Breteau index) (35.1%, 16.7% to 55.5%), and fewer pupae per person (51.7%, 36.2% to 76.1%). The numbers needed to treat were 30 (95% confidence interval 20 to 59) for a lower risk of infection in children, 71 (48 to 143) for fewer reports of dengue illness, 17 (14 to 20) for the house index, 37 (35 to 67) for the container index, 10 (6 to 29) for the Breteau index, and 12 (7 to 31) for fewer pupae per person. Secondary per protocol analysis showed no serological evidence of a protective effect of temephos. CONCLUSIONS: Evidence based community mobilization can add effectiveness to dengue vector control. Each site implementing the intervention in its own way has the advantage of local customization and strong community engagement. TRIAL REGISTRATION: ISRCTN27581154.

Auditing Nicaragua's anti-corruption struggle, 1998 to 2009.

BACKGROUND: Four social audits in 1998, 2003, 2006 and 2009 identified actions that Nicaragua could take to reduce corruption and public perception in primary health care and other key services. METHODS: In a 71-cluster sample, weighted according to the 1995 census and stratified by geographic region and settlement type, we audited the same five public services: health centres and health posts, public primary schools, municipal government, transit police and the courts. Some 6,000 households answered questions about perception and personal experience of unofficial and involuntary payments, payments without obtaining receipts or to the wrong person, and payments "to facilitate" services in municipal offices or courts. Additional questions covered complaints about corruption and confidence in the country's anti-corruption struggle. Logistic regression analyses helped clarify local variations and explanatory variables. Feedback to participants and the services at both national and local levels followed each social audit. RESULTS: Users' experience of corruption in health services, education and municipal government decreased. The wider population's perception of corruption in these sectors decreased also, but not as quickly. Progress among traffic police faltered between 2006 and 2009 and public perception of police corruption ticked upwards in parallel with drivers' experience. Users' experience of corruption in the courts worsened over the study period--with the possible exception of Managua between 2006 and 2009--but public perception of judicial corruption, after peaking in 2003, declined from then on. Confidence in the anti-corruption struggle grew from 50% to 60% between 2003 and 2009. Never more than 8% of respondents registered complaints about corruption.Factors associated with public perception of corruption were: personal experience of corruption, quality of the service itself, and the perception that municipal government takes community opinion into account and keeps people informed about how it uses public funds. CONCLUSIONS: Lowering citizens' perception of corruption in public services depends on reducing their experience of it, on improving service quality and access and--perhaps most importantly--on making citizens feel they are well-informed participants in the work of government.

Algunos problemas de morbilidad y factores asociados en un batallón de infantería de reserva en período de movilización

El presente estudio pretende contribuir al conocimiento de algunos aspectos del proceso salud-enfermedad relevantes para la disposición combativa, en los batallones de reserva en período de movilización y algunos factores asociados. Se diseño un estudio longitudinal con fines descriptivos del problema de investigación, en cual se realizó en el Batallón objeto de estudio durante un período de 24 días; en dos fases principales; una de ella fue recabar al inicio del período de movilización, toda la información relativa al perfil de salud-enfermedad previo y el perfil reproductivo de clase del universo. La otra fase consistió en registrar día a día la información necesaria correspondiente al resto de variables. Los resultados de la investigación permitieron en su primera fase determinar la composición social del batallón, los antecedentes patólogicos personales más relevantes y algunos aspectos del perfil salud previo a la movilización. En su segunda fase se identificaron los niveles de frecuencia de las patologías sujetas a estudio y su relación con algunos aspectos del perfil reproductivo de clase de los reservistas y factores del contexto operativo de movilización. Asimismo se conoció la prevalencia de esas patologías durante el período y las causas más frecuentes de consulta médica.