Acceptability of impregnated school uniforms for dengue control in Thailand: a mixed methods approach

Facilitators and barriers to engaging communities in health service research on dengue control in Indo-Pacific region: a systematic review

BACKGROUND

Dengue is a public health problem in the Indo-Pacific countries. There are concerns over the facilitators and barriers to community engagement in health service research aimed at dengue control. The objective of his study was to identify and synthesize facilitators and barriers to community engagement in health service research aimed at dengue control.

METHODOLOGY

The Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) checklist was used to perform this review. Health-related databases including PubMed, Ovid, and Google Scholar were searched for relevant studies. A consolidated framework with five domains was developed after undertaking a six-phase reflective thematic assessment of the data.

RESULTS

Thirteen studies were identified, spanning eight low-and middle-income countries of the Indo-Pacific region including Cambodia, India, Indonesia, Myanmar, Philippines, Sri Lanka, Thailand, and Vietnam. The studies in this review covered the period from 2002 to 2021. A broad range of study designs and objectives were revealed across these 13 studies. An array of communities such as the local government, project-related health staff, local health services staff, community leaders, local communities/residences/general public, heads of households, community health volunteers, school teachers, and schoolchildren participated in these dengue related studies. The five Consolidated Framework for Implementation Research (CFIR) domains of 'intervention characteristics', 'inner setting', 'outer setting',' individual characteristics', and 'program implementations' were used to identify and describe barriers and facilitators.

CONCLUSIONS

The findings indicate a range of barriers and facilitators to community engagement in dengue control in the selected LMIC in the Indo-Pacific countries. Future health services research on dengue control approaches should be carefully planned, methodologically constructed, aligned with community engagement principles, and involve considerable community participation at all stages of the research.

Knowledge, attitude and practice (KAP) and risk factors on dengue fever among children in Brazil, Fortaleza: A cross-sectional study

BACKGROUND

Dengue fever is a mosquito-borne viral disease that is associated with four serotypes of the dengue virus. Children are vulnerable to infection with the dengue virus, particularly those who have been previously infected with a different dengue serotype. Sufficient knowledge, positive attitudes, and proper practices (KAP) are essential for dengue prevention and control. This study aims to estimate the dengue seropositivity for study participants and to examine the association between households' dengue-related knowledge, attitudes, and practices (KAP), and children's risk of dengue seropositivity, while accounting for socioeconomic and demographic differences in Brazil.

METHODOLOGY/PRINCIPAL FINDINGS

This analysis was based on a cross-sectional study from Fortaleza, Brazil between November 2019, and February 2020. There were 392 households and 483 participant children who provided a sample of sufficient quality for serological analysis. The main exposure was a household's dengue-related knowledge, attitudes, and practices, assessed through a questionnaire to construct a composite KAP score categorized into three levels: low, moderate, and high. The main outcome is dengue immunoglobulin G(IgG) antibodies, collected using dried blood spots and assessed with Panbio Dengue IgG indirect ELISA (enzyme-linked immunosorbent assays) test commercial kits. The estimated crude dengue seroprevalence among participating children (n = 483) was 25%. Five percent of households (n = 20) achieved a score over 75% for KAP, sixty-nine percent of households (n = 271) scored between 50% and 75%, and twenty-six percent of households (n = 101) scored lower than 50%. Each KAP domain was significantly and positively associated with the others. The mean percentage scores for the three domains are 74%, 63%, and 39% respectively. We found high household KAP scores were associated with an increased adjusted relative risk (aRR) of seropositivity (aRR: 2.11, 95% CI: 1.11-4.01, p = 0.023). Household adult respondents' education level of elementary school or higher was negatively associated with children's risk of being seropositive (aRR: 0.65, 95% CI: 0.48-0.87, p = 0.005). The risk of seropositivity in older children (6-12 years old) was over 6 times that of younger children (2-5 years old) (aRR: 6.08, 95% CI: 3.47-10.64, p<0.001). Children living in households with sealed water tanks or no water storage had a lower risk of being seropositive (aRR: 0.73, 95% CI: 0.54-0.98, p = 0.035).

CONCLUSIONS/SIGNIFICANCE

Our results provide insight into the prevalence of dengue seropositivity in Fortaleza, Brazil in children, and certain demographic and socioeconomic characteristics associated with children's risk of being seropositive. They also suggest that KAP may not identify those more at-risk for dengue, although understanding and enhancing households' KAP is crucial for effective community dengue control and prevention initiatives.

Reviewing School Uniform through a Public Health Lens: Evidence about the Impacts of School Uniform on Education and Health

This study uses a public health lens to review evidence about the impacts of wearing a school uniform on students’ health and educational outcomes. It also reviews the underlying rationales for school uniform use, exploring historical reasons for uniform use, as well as how questions of equity, human rights, and the status of children as a vulnerable group are played out in debates over school uniforms. The literature identified indicates that uniforms have no direct impact on academic performance, yet directly impact physical and psychological health. Girls, ethnic and religious minorities, gender-diverse students and poorer students suffer harm disproportionately from poorly designed uniform policies and garments that do not suit their physical and socio-cultural needs. Paradoxically, for some students, uniform creates a barrier to education that it was originally instituted to remedy. The article shows that public health offers a new perspective on and contribution to debates and rationales for school uniform use. This review lays out the research landscape on school uniform and highlights areas for further research.

Novel tools for the surveillance and control of dengue: findings by the DengueTools research consortium

BACKGROUND

Dengue fever persists as a major global disease burden, and may increase as a consequence of climate change. Along with other measures, research actions to improve diagnosis, surveillance, prevention, and predictive models are highly relevant. The European Commission funded the DengueTools consortium to lead a major initiative in these areas, and this review synthesises the outputs and findings of this work conducted from 2011 to 2016. Research areas: DengueTools organised its work into three research areas, namely [1] Early warning and surveillance systems; [2] Strategies to prevent dengue in children; and [3] Predictive models for the global spread of dengue. Research area 1 focused on case-studies undertaken in Sri Lanka, including developing laboratory-based sentinel surveillance, evaluating economic impact, identifying drivers of transmission intensity, evaluating outbreak prediction capacity and developing diagnostic capacity. Research area 2 addressed preventing dengue transmission in school children, with case-studies undertaken in Thailand. Insecticide-treated school uniforms represented an intriguing potential approach, with some encouraging results, but which were overshadowed by a lack of persistence of insecticide on the uniforms with repeated washing. Research area 3 evaluated potential global spread of dengue, particularly into dengue-naïve areas such as Europe. The role of international travel, changing boundaries of vectors, developing models of vectorial capacity under different climate change scenarios and strategies for vector control in outbreaks was all evaluated.

CONCLUDING REMARKS

DengueTools was able to make significant advances in methods for understanding and controlling dengue transmission in a range of settings. These will have implications for public health agendas to counteract dengue, including vaccination programmes.

OUTLOOK

Towards the end of the DengueTools project, Zika virus emerged as an unexpected epidemic in the central and southern America. Given the similarities between the dengue and Zika viruses, with vectors in common, some of the DengueTools thinking translated readily into the Zika situation.

Acceptability of insecticide-treated clothing for malaria prevention among migrant rubber tappers in Myanmar: a cluster-randomized non-inferiority crossover trial

Background

Insecticide-treated clothing (ITC) has long been used for military and outdoor recreational purposes and there is substantial evidence to show that it can protect against arthropod biting. As a complementary vector control measure, ITC could be used to address outdoor transmission of malaria, particularly among mobile and migrant populations and night-time workers such as rubber tappers, who may be beyond the reach of core interventions. However, more information is required on acceptability and preferences of target groups towards ITC to understand whether it could be a viable strategy in Myanmar.

Methods

A cluster-randomized, double-blind, non-inferiority crossover trial was performed to determine acceptability of ITC versus identical, untreated clothing (NTC) among migrant rubber tappers. The study took place between January and May 2015 with 234 participants in 16 clusters in Thanbyuzayat Township, Mon State, Myanmar. Participants were randomly assigned to the order of clothing distribution and followed up at 2, 4 and 6 week intervals. Acceptability was assessed through structured questionnaires, focus group discussions and in-depth interviews. A cluster-level non-inferiority analysis was conducted using STATA, while qualitative data were digitally recorded, transcribed and content-analysed to identify patterns and themes, and managed thematically in Excel 2010^®.

Results

Acceptability of both types of clothing was high. ITC was deduced to be non-inferior to NTC for seven out of eight indicators regarding perceptions (looks nice, is durable, is pleasant to wear for nighttime work, reduces mosquito bites, would recommend the clothing, would buy the clothing, like the clothing overall). A high proportion of respondents reported that the clothing reduced mosquito bites (ITC-98%; NTC-94%). Clothing was worn regularly (about 11 times in the previous two weeks). The most common reasons for not wearing the clothing every night were that it was being washed or dried, or the participant did not go to work.

Conclusions

The high level of acceptability suggests that ITC could be an appropriate strategy for personal protection amongst migrant rubber tappers in outdoor transmission settings in Myanmar. However, more research is needed into the feasibility and protective efficacy of ITC before it can be considered for wider roll-out.

Trial registration Clinical trials ACTRN12615000432516

Mitigating Diseases Transmitted by Aedes Mosquitoes: A Cluster-Randomised Trial of Permethrin-Impregnated School Uniforms

Background

Viral diseases transmitted via Aedes mosquitoes are on the rise, such as Zika, dengue, and chikungunya. Novel tools to mitigate Aedes mosquitoes-transmitted diseases are urgently needed. We tested whether commercially insecticide-impregnated school uniforms can reduce dengue incidence in school children.

Methods

We designed a cluster-randomised controlled trial in Thailand. The primary endpoint was laboratory-confirmed dengue infections. Secondary endpoints were school absenteeism; and impregnated uniforms’ 1-hour knock-down and 24 hour mosquito mortality as measured by standardised WHOPES bioassay cone tests at baseline and after repeated washing. Furthermore, entomological assessments inside classrooms and in outside areas of schools were conducted.

Results

We enrolled 1,811 pupils aged 6–17 from 5 intervention and 5 control schools. Paired serum samples were obtained from 1,655 pupils. In the control schools, 24/641 (3.7%) and in the intervention schools 33/1,014 (3.3%) students had evidence of new dengue infections during one school term (5 months). There was no significant difference in proportions of students having incident dengue infections between the intervention and control schools, with adjustment for clustering by school. WHOPES cone tests showed a 100% knock down and mortality of Aedes aegypti mosquitoes exposed to impregnated clothing at baseline and up to 4 washes, but this efficacy rapidly declined to below 20% after 20 washes, corresponding to a weekly reduction in knock-down and mosquito mortality by 4.7% and 4.4% respectively. Results of the entomological assessments showed that the mean number of Aedes aegypti mosquitoes caught inside the classrooms of the intervention schools was significantly reduced in the month following the introduction of the impregnated uniforms, compared to those collected in classrooms of the control schools (p = 0.04)

Conclusions

Entomological assessments showed that the intervention had some impact on the number of Aedes mosquitoes inside treatment schools immediately after impregnation and before insecticidal activity declined. However, there was no serological evidence of protection against dengue infections over the five months school term, best explained by the rapid washing-out of permethrin after 4 washes. If rapid washing-out of permethrin could be overcome by novel technological approaches, insecticide-treated clothes might become a potentially cost-effective and scalable intervention to protect against diseases transmitted by Aedes mosquitoes such as dengue, Zika, and chikungunya.

Trial Registration

ClinicalTrials.gov NCT01563640

Viral diseases transmitted via Aedes mosquitoes are on the rise, such as Zika, dengue, and chikungunya. Novel tools to mitigate Aedes mosquitoes-transmitted diseases are urgently needed. We tested whether commercially available insecticide-impregnated school uniforms can reduce dengue incidence in school children. To test this hypothesis we designed a school based randomized controlled trial where we enrolled 1,811 school children aged 6–17. For study monitoring, we also measured the effect of the impregnated uniforms on the survival of Aedes mosquitoes based on a standard bioassay test called WHOPES cone test. Furthermore, we counted the number of Aedes mosquitoes in classrooms and outside areas of classrooms. In the control schools, 3.7% and in the intervention schools 3.3% of the students had evidence of new dengue infections during the 5 month long school term, which indicates that there was no protection against dengue infections despite the fact that the knockdown effect of the impregnated uniforms was very high in the laboratory. We also showed a significant reduction of Aedes mosquitoes in the classrooms of the intervention schools. So why did this not translate into clinical protection against dengue? We assume the reason was the rapid wash-out effect of permethrin. Despite the company’s claim that impregnated clothing would withstand up to 70 launderings, we found a rapid decline in permethrin efficacy already after 4 washes, with the efficacy to below 20% after 20 washes. If rapid washing-out of permethrin could be overcome by novel technological approaches, insecticide-treated clothes might become a potentially cost-effective and scalable intervention to protect against diseases transmitted by Aedes mosquitoes such as dengue, Zika, and chikungunya.

Risk and Control of Mosquito-Borne Diseases in Southeast Asian Rubber Plantations

Unprecedented economic growth in Southeast Asia (SEA) has encouraged the expansion of rubber plantations. This land-use transformation is changing the risk of mosquito-borne diseases. Mature plantations provide ideal habitats for the mosquito vectors of malaria, dengue, and chikungunya. Migrant workers may introduce pathogens into plantation areas, most worryingly artemisinin-resistant malaria parasites. The close proximity of rubber plantations to natural forest also increases the threat from zoonoses, where new vector-borne pathogens spill over from wild animals into humans. There is therefore an urgent need to scale up vector control and access to health care for rubber workers. This requires an intersectoral approach with strong collaboration between the health sector, rubber industry, and local communities.

Long-Lasting Permethrin-Impregnated Clothing Protects Against Mosquito Bites in Outdoor Workers

Outdoor exposure to mosquitoes is a risk factor for many diseases, including malaria and dengue. We have previously shown that long-lasting permethrin-impregnated clothing protects against tick and chigger bites in a double-blind randomized controlled trial in North Carolina outdoor workers. Here, we evaluated whether this clothing is protective against mosquito bites by measuring changes in antibody titers to mosquito salivary gland extracts. On average, there was a 10-fold increase in titer during the spring and summer when mosquito exposure was likely to be the highest. During the first year of the study, the increase in titer in subjects wearing treated uniforms was 2- to 2.5-fold lower than that of control subjects. This finding suggests that long-lasting permethrin-impregnated clothing provided protection against mosquito bites.

Use of insecticide-treated school uniforms for prevention of dengue in schoolchildren: a cost-effectiveness analysis

BACKGROUND

Dengue-related illness is a leading cause of hospitalization and death, particularly among children. Practical, acceptable and affordable measures are urgently needed to protect this age group. Schools where children spend most of their day is proposed as an ideal setting to implement preventive strategies against day-biting Aedes mosquitoes. The use of insecticide-treated school uniforms is a promising strategy currently under investigation.

METHODS

Using a decision-analytic model, we evaluated the cost-effectiveness of the use of insecticide-treated school uniforms for prevention of dengue, compared with a "do-nothing" alternative, in schoolchildren from the societal perspective. We explored how the potential economic value of the intervention varied under various scenarios of intervention effectiveness and cost, as well as dengue infection risk in school-aged children, using data specific to Thailand.

RESULTS

At an average dengue incidence rate of 5.8% per year in school-aged children, the intervention was cost-effective (ICER≤$16,440) in a variety of scenarios when the intervention cost per child was $5.3 or less and the intervention effectiveness was 50% or higher. In fact, the intervention was cost saving (ICER<0) in all scenarios in which the intervention cost per child was $2.9 or less per year and the intervention effectiveness was 50% or higher. The results suggested that this intervention would be of no interest to Thai policy makers when the intervention cost per child was $10.6 or higher per year regardless of intervention effectiveness (ICER>$16,440).

CONCLUSIONS

Our results present the potential economic value of the use of insecticide-treated uniforms for prevention of dengue in schoolchildren in a typical dengue endemic setting and highlight the urgent need for additional research on this intervention.