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Colombia has a tropical climate and environmental conditions that favour the circulation of most of the known vector-borne diseases (VBDs). Protocols have been established and implemented to address the threats of these diseases, but they are for country-wide use and do not take into consideration the nuances of the different environments of the country. Almost the entire population is vulnerable to infection with one or more VBD. This study aims to characterise the perceptions and experiences of stakeholders involved in vector control and VBDs in the Orinoquia region in Colombia. Two panel discussions, and 12 semi-structured interviews, were conducted. Experts from the Colombian National Health Institute (INS), health secretaries from Meta, Guaviare and Vichada Departments, academic researchers, and individuals from private vector control companies participated. All sessions were recorded, transcribed, and translated, and then subject to thematic analysis. Three major themes emerged: involvement, limitations, and recommendations. Results showed that participants are engaged in vector surveillance activities, education, and vector control research. Participants focused on problems of disjointed efforts towards VBD control between health secretaries and the health ministry, as well as societal issues, such as socioeconomic, cultural, and political issues, which became the rationale for the lack of vector control resources. Responses in the panel discussions and interviews overlapped in opinions, and suggested that vector control could be improved through better communication between vector control bodies, strengthened engagement with vulnerable communities, more collaborative actions, and a more balanced distribution of resources.

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Among the efforts to reduce mosquito-transmitted diseases, such as malaria and dengue fever, essential oils (EOs) have become increasingly popular as natural replacements for the repellant DEET. In this study, seven commercially available plant EOs against Aedes species mosquitoes were evaluated for their complete protection time (CPT, min) in vivo using human-hand in cage tests (GB2009/China and WHO2009). Among the EOs with the highest efficacy in repelling mosquitoes, Aedes albopictus (Skuse) were clove bud oil and patchouli oil. Both were further assessed according to the in vivo method recommended by the WHO, to determine their minimum effective dose and CPT. A comparison of the ED50 values (dose yielding a 50% repellent response) of these two EOs against Aedes aegypti(L.) showed that the ED50 (2.496 µg/cm2) of patchouli oil was 1248 times higher than that of clove bud oil (0.002 µg/cm2), thus demonstrating them greater efficacy of the latter in repelling Ae. aegypti mosquitoes. For the 2 EOs, eugenol was the major component with higher than 80% in relative amount of the clove bud oil. The patchouli oil had more than 30% of character chemical patchouli alcohol along with α-bulnesene (10.962%), α-guaiene (9.227%), and seychellene (7.566%). Clove bud oil was found to confer longer complete protection than patchouli oil against a common species of mosquito. These results suggest use of EOs as safe, highly potent repellents for use in daily life and against mosquito-transmitted diseases, such as malaria and dengue fever.

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Insecticides and repellents are routinely used in Brazil because of the high rates of arbovirus transmission and the nuisance caused by mosquitoes. However, few studies have assessed the effectiveness of repellents against mosquito populations that have been under exposure to xenobiotics, mainly insecticides and repellents. This study investigated the sensitivity of a field population of Aedes aegypti (Linnaeus, 1762) from a dengue-endemic area under high insecticide pressure to N,N-diethylmethylbenzamide (DEET), the active ingredient in common repellent products. The field (Laranjeiras, Sergipe, Brazil) and laboratory (Rockefeller) populations were characterized for the presence of the Val1016Ile kdr mutation, associated with pyrethroid resistance, and locomotor activity. Repellency bioassays were performed to assess the response of the mosquitoes to human odor by exposing them to 10% DEET applied to the skin in ethanol. Samples from the field population showed higher frequency of the kdr mutation, 21.9% homozygous and 21.9% heterozygous, greater locomotor activity and greater sensitivity to DEET than the laboratory population. These results suggest increased sensitivity to DEET in field populations and a possible interaction between insecticide exposure and sensitivity to DEET.

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OBJECTIVE: The World Health Organization declared a Public Health Emergency of International Concern following the rapid emergence of neonatal microcephaly in Brazil during the 2015-2016 Zika virus (ZIKV) epidemic. In response, a national campaign sought to control Aedes mosquito populations and reduce ZIKV transmission. Achieving adherence to vector control or mosquito-bite reduction behaviours, including the use of topical mosquito repellents, is challenging. Coproduction of research at the community level is needed to understand and mitigate social determinants of lower engagement with Aedes preventive measures, particularly within disempowered groups. DESIGN: In 2017, the Zika Preparedness Latin America Network (ZikaPLAN) conducted a qualitative study to understand individual and community level experiences of ZIKV and other mosquito-borne disease outbreaks. Presented here is a thematic analysis of 33 transcripts from community focus groups and semistructured interviews, applying the Health Belief Model (HBM) to elaborate knowledge, attitudes and perceptions of ZIKV and vector control strategies. PARTICIPANTS: 120 purposively sampled adults of approximate reproductive age (18-45); 103 women participated in focus groups and 17 men in semistructured interviews. SETTING: Two sociopolitically and epidemiologically distinct cities in Brazil: Jundiaí (57 km north of São Paolo) and Salvador (Bahia state capital). RESULTS: Four key and 12 major themes emerged from the analysis: (1) knowledge and cues to action; (2) attitudes and normative beliefs (perceived threat, barriers, benefits and self-efficacy); (3) behaviour change (household prevention and community participation); and (4) community preferences for novel repellent tools, vector control strategies and ZIKV messaging. CONCLUSIONS: Common barriers to repellent adherence were accessibility, appearance and effectiveness. A strong case is made for the transferability of the HBM to inform epidemic preparedness for mosquito-borne disease outbreaks at the community level. Nationally, a health campaign targeting men is recommended, in addition to local mobilisation of funding to strengthen surveillance, risk communication and community engagement.

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BACKGROUND: The outbreak of Zika virus in Brazil in 2015 followed the arrival of chikungunya in 2014 and a long history of dengue circulation. Vital to the response to these outbreaks of mosquito-borne pathogens has been the dissemination of public health messages, including those promoted through risk communication posters. This study explores the content of a sample of posters circulated in Brazil towards the end of the Zika epidemic in 2017 and analyses their potential effectiveness in inducing behaviour change. METHODS: A content analysis was performed on 37 posters produced in Brazil to address outbreaks of mosquito-borne pathogens. The six variables of the Health Belief Model were used to assess the potential effectiveness of the posters to induce behaviour change. RESULTS: Three overarching key messages emerged from the posters. These included (i) the arboviruses and their outcomes, (ii) a battle against the mosquito, and (iii) a responsibility to protect and prevent. Among the six variables utilised through the Health Belief Model, cues to action were most commonly featured, whilst the perceived benefits of engaging in behaviours to prevent arbovirus transmission were the least commonly featured. CONCLUSIONS: The posters largely focused on mosquito-borne transmission and the need to eliminate breeding sites, and neglected the risk of the sexual and congenital transmission of Zika and the importance of alternative preventive actions. This, we argue, may have limited the potential effectiveness of these posters to induce behaviour change.

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BACKGROUND: Arboviruses transmitted by day-biting Aedes mosquitoes are a major public health concern. With the challenges inherent in arbovirus vaccine and therapeutics development, vector control and bite prevention strategies are among the limited options available for immediate intervention. Bite prevention through personal protective technologies (PPT), such as topical mosquito repellents or repellent-impregnated clothing, may help to decrease biting rates and, therefore, the risk of disease in groups most susceptible to adverse outcomes from Zika virus. However, achieving high uptake and compliance with PPT can be challenging. METHODOLOGY/PRINCIPAL FINDINGS: To gain an insight into the knowledge and concerns of pregnant women surrounding Zika and their opinions regarding PPT, particularly repellent clothing, a focus group study was carried out with pregnant women, women of reproductive age, and semi-structured interviews with their male partners in two cities in Colombia. The discussions revealed shortfalls in basic knowledge of Zika virus, with several pregnant participants reporting being unaware of the potential for Zika-related congenital malformations. Although participants generally considered Zika to be a significant personal threat, most rated it as less of a concern than dengue or diarrheal diseases. Overall, repellent clothing and other forms of PPT were viewed as effective, although some participants expressed concerns over the high costs of repellents, and safety fears of regular contact with repellent chemicals, which they perceived as potentially harmful. Plant-derived repellents were considered to be safer than synthetic chemical repellents. Discussions also highlighted that health centers were the preferred source of information on bite-reduction. CONCLUSIONS/SIGNIFICANCE: Achieving high uptake and compliance with PPT in populations most at risk of adverse outcomes from Zika infection requires engaging key users in open dialogue to identify and address any practical issues regarding PPT use, and concerns over safety. The findings presented here suggest that educational campaigns should strongly emphasize the risks associated with Zika during pregnancy, and discuss safety profiles of approved synthetic repellents and the availability of EPA-approved plant-based repellents. In addition, the economic and political context should be a major consideration when evaluating personal mosquito-repellent strategies.

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