Assessment of community support for Wolbachia-mediated population suppression as a control method for Aedes aegypti mosquitoes in a community cohort in Puerto Rico

Comparison of the Sensitivity and Specificity of Commercial Anti-Dengue Virus IgG Tests to Identify Persons Eligible for Dengue Vaccination

The Advisory Committee on Immunization Practices (ACIP) recommended that dengue pre-vaccination screening tests for Dengvaxia administration have at least 98% specificity and 75% sensitivity. This study evaluates the performance of commercial anti-DENV IgG tests to identify tests that could be used for pre-vaccination screening. First, for 7 tests, we evaluated sensitivity and specificity in early convalescent dengue virus (DENV) infection, using 44 samples collected 7-30 days after symptom onset and confirmed by RT-PCR. Next, for the 5 best performing tests and two additional tests (with and without an external test reader) that became available later, we evaluated performance to detect past dengue infection among a panel of 44 specimens collected in 2018-2019 from healthy 9-16-year-old children from Puerto Rico. Finally, a full-scale evaluation was done with the 4 best performing tests using 400 specimens from the same population. We used virus focus reduction neutralization test and an in-house DENV IgG ELISA as reference standards. Of seven tests, five showed ≥75% sensitivity detecting anti-DENV IgG in early convalescent specimens with low cross-reactivity to Zika virus. For the detection of previous DENV infections the tests with the highest performance were the Euroimmun NS1 IgG ELISA (sensitivity 84.5%, specificity 97.1%) and CTK Dengue IgG rapid test R0065C with the test reader (sensitivity 76.2% specificity 98.1%). There are IgG tests available that can be used to accurately classify individuals with previous DENV infection as eligible for dengue vaccination to support safe vaccine implementation.

Willingness to accept and participate in a Microsporidia MB-based mosquito release strategy: a community-based rapid assessment in western Kenya

BACKGROUND

Microsporidia MB, an endosymbiont naturally found in Anopheles mosquitoes inhibits transmission of Plasmodium and is a promising candidate for a transmission-blocking strategy that may involve mosquito release. A rapid assessment was carried out to develop insight into sociodemographic factors, public health concerns, and malaria awareness, management, and prevention practices with the willingness to accept and participate in Microsporidia MB-based transmission-blocking strategy to develop an informed stakeholder engagement process.

METHODS

The assessment consisted of a survey conducted in two communities in western Kenya that involved administering a questionnaire consisting of structured, semi-structured, and open questions to 8108 household heads.

RESULTS

There was an overall high level of willingness to accept (81%) and participate in the implementation of the strategy (96%). Although the willingness to accept was similar in both communities, Ombeyi community was more willing to participate (OR 22, 95% CI 13-36). Women were less willing to accept (OR 0.8, 95% CI 0.7-0.9) compared to men due to fear of increased mosquito bites near homes. Household heads with incomplete primary education were more willing to accept (OR 1.6, 95% CI 01.2-2.2) compared to those educated to primary level or higher. Perceiving malaria as a moderate or low public health issue was also associated with a lower willingness to accept and participate. Experience of > 3 malaria cases in the family over the last six months and knowledge that malaria is transmitted by only mosquito bites, increased the willingness to accept but reduced the willingness to participate. Awareness of malaria control methods based on mosquitoes that cannot transmit malaria increases the willingness to participate.

CONCLUSION

The study showed a high level of willingness to accept and participate in a Microsporidia MB-based strategy in the community, which is influenced by several factors such as community, disease risk perception, gender, education level, knowledge, and experience of malaria. Further research will need to focus on understanding the concerns of women, educated, and employed community members, and factors that contribute to the lower disease risk perception. This improved understanding will lead to the development of an effective communication strategy.

Investigating SARS-CoV-2 Incidence and Morbidity in Ponce, Puerto Rico: Protocol and Baseline Results From a Community Cohort Study

BACKGROUND

A better understanding of SARS-CoV-2 infection risk among Hispanic and Latino populations and in low-resource settings in the United States is needed to inform control efforts and strategies to improve health equity. Puerto Rico has a high poverty rate and other population characteristics associated with increased vulnerability to COVID-19, and there are limited data to date to determine community incidence.

OBJECTIVE

This study describes the protocol and baseline seroprevalence of SARS-CoV-2 in a prospective community-based cohort study (COPA COVID-19 [COCOVID] study) to investigate SARS-CoV-2 infection incidence and morbidity in Ponce, Puerto Rico.

METHODS

In June 2020, we implemented the COCOVID study within the Communities Organized to Prevent Arboviruses project platform among residents of 15 communities in Ponce, Puerto Rico, aged 1 year or older. Weekly, participants answered questionnaires on acute symptoms and preventive behaviors and provided anterior nasal swab samples for SARS-CoV-2 polymerase chain reaction testing; additional anterior nasal swabs were collected for expedited polymerase chain reaction testing from participants that reported 1 or more COVID-19-like symptoms. At enrollment and every 6 months during follow-up, participants answered more comprehensive questionnaires and provided venous blood samples for multiantigen SARS-CoV-2 immunoglobulin G antibody testing (an indicator of seroprevalence). Weekly follow-up activities concluded in April 2022 and 6-month follow-up visits concluded in August 2022. Primary study outcome measures include SARS-CoV-2 infection incidence and seroprevalence, relative risk of SARS-CoV-2 infection by participant characteristics, SARS-CoV-2 household attack rate, and COVID-19 illness characteristics and outcomes. In this study, we describe the characteristics of COCOVID participants overall and by SARS-CoV-2 seroprevalence status at baseline.

RESULTS

We enrolled a total of 1030 participants from 388 households. Relative to the general populations of Ponce and Puerto Rico, our cohort overrepresented middle-income households, employed and middle-aged adults, and older children (P<.001). Almost all participants (1021/1025, 99.61%) identified as Latino/a, 17.07% (175/1025) had annual household incomes less than US $10,000, and 45.66% (463/1014) reported 1 or more chronic medical conditions. Baseline SARS-CoV-2 seroprevalence was low (16/1030, 1.55%) overall and increased significantly with later study enrollment time (P=.003).

CONCLUSIONS

The COCOVID study will provide a valuable opportunity to better estimate the burden of SARS-CoV-2 and associated risk factors in a primarily Hispanic or Latino population, assess the limitations of surveillance, and inform mitigation measures in Puerto Rico and other similar populations.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR1-10.2196/53837.

Preferences and Demand for Mosquito Control among Dengue-Endemic Communities in Peñuelas, Puerto Rico: An Application of the Best-Worst Choice Model

Aedes aegypti is the primary vector of dengue virus and threatens 3.9 billion people living in many tropical and subtropical countries. Prevention and reduction of dengue and other Aedes-borne viruses, including Zika and chikungunya, requires control of mosquito populations. Community mobilization and input are essential components of vector control efforts. Many vector control campaigns do not engage communities prior to implementation, leading to program failure. Those that do often conduct basic knowledge, attitude, and practice surveys that are not designed to explicitly elicit preferences. Here, we applied a novel stated preference elicitation tool, best-worst choice, to understand preferences, willingness to participate, and willingness to pay for mosquito control in dengue-endemic communities of Peñuelas, Puerto Rico. Findings revealed that the community preferred mosquito control programs that are 1) applied at the neighborhood level, 2) implemented by the local government, and 3) focused specifically on reducing disease transmission (e.g., dengue) instead of mosquito nuisance. Programs targeting the reduction of disease transmission and higher educational level of participants increased willingness to participate. Participants were willing to pay an average of $72 annually to have a program targeting the reduction of diseases such as dengue. This study serves as a model to engage communities in the design of mosquito control programs and improve stakeholders' decision-making.

Acceptability of emergent Aedes aegypti vector control methods in Ponce, Puerto Rico: A qualitative assessment

Aedes aegypti control has been fraught with challenges in Puerto Rico. The government has implemented commonly used vector control methods, but arboviral epidemics still occur. It is necessary to explore new Ae. aegypti control methods. This study aimed to understand the perceptions of community members in Ponce, Puerto Rico about emergent and traditional Ae. aegypti vector control methods and determine their acceptability and support for these methods. We identified the type of information needed to increase support for emergent vector control methods, and the preferred strategies to disseminate this information. Four group discussions were conducted with a total of 32 participants representing eight of the 14 clusters participating in the Communities Organized for the Prevention of Arboviruses (COPA), a project designed to mobilize communities in Ponce, Puerto Rico to prevent diseases transmitted by mosquitoes. Group discussions began with an overview of different methods used for controlling Ae. aegypti mosquitoes. These overviews facilitated participant understanding of the mosquito control methods presented. Use of source reduction, autocidal gravid ovitraps (AGO), and manual application of larvicide for arboviral mosquito control received support from almost all participants. Vector control methods that use more familiar techniques in Puerto Rico such as truck-mounted larvicide spraying (TMLS) and insecticide residual spraying received support from most participants. More than half of participants supported the use of emergent mosquito control methods including Wolbachia suppression, Wolbachia replacement, or genetically modified mosquitoes (GMM). Participants preferred to receive vector control information through house-to-house visits with the distribution of written materials, followed by dissemination of information through traditional (i.e., radio, television) and social media. The detailed information resulting from this study was used to develop messages for a communications campaign to garner future community support. Community acceptance and support are critical for the success of vector control programs using emergent mosquito control methods.

Symbiotic Wolbachia in mosquitoes and its role in reducing the transmission of mosquito-borne diseases: updates and prospects

Mosquito-borne diseases such as malaria, dengue fever, West Nile virus, chikungunya, Zika fever, and filariasis have the greatest health and economic impact. These mosquito-borne diseases are a major cause of morbidity and mortality in tropical and sub-tropical areas. Due to the lack of effective vector containment strategies, the prevalence and severity of these diseases are increasing in endemic regions. Nowadays, mosquito infection by the endosymbiotic Wolbachia represents a promising new bio-control strategy. Wild-infected mosquitoes had been developing cytoplasmic incompatibility (CI), phenotypic alterations, and nutrition competition with pathogens. These reduce adult vector lifespan, interfere with reproduction, inhibit other pathogen growth in the vector, and increase insecticide susceptibility of the vector. Wild, uninfected mosquitoes can also establish stable infections through trans-infection and have the advantage of adaptability through pathogen defense, thereby selectively infecting uninfected mosquitoes and spreading to the entire population. This review aimed to evaluate the role of the Wolbachia symbiont with the mosquitoes (Aedes, Anopheles, and Culex) in reducing mosquito-borne diseases. Global databases such as PubMed, Web of Sciences, Scopus, and pro-Quest were accessed to search for potentially relevant articles. We used keywords: Wolbachia, Anopheles, Aedes, Culex, and mosquito were used alone or in combination during the literature search. Data were extracted from 56 articles' texts, figures, and tables of the included article.

Previous Dengue Infection among Children in Puerto Rico and Implications for Dengue Vaccine Implementation

Limited dengue virus (DENV) seroprevalence estimates are available for Puerto Rico, which are needed to inform the potential use and cost-effectiveness of DENV vaccines. The Communities Organized to Prevent Arboviruses (COPA) is a cohort study initiated in 2018 in Ponce, Puerto Rico, to assess arboviral disease risk and provide a platform to evaluate interventions. We recruited participants from households in 38 study clusters, who were interviewed and provided a serum specimen. Specimens from 713 children aged 1 to 16 years during the first year of COPA were tested for the four DENV serotypes and ZIKV using a focus reduction neutralization assay. We assessed the seroprevalence of DENV and ZIKV by age and developed a catalytic model from seroprevalence and dengue surveillance data to estimate the force of infection for DENV during 2003-2018. Overall, 37% (n = 267) were seropositive for DENV; seroprevalence was 9% (11/128) among children aged 1 to 8 years and 44% (256/585) among children aged 9 to 16 years, exceeding the threshold over which DENV vaccination is deemed cost-effective. A total of 33% were seropositive for ZIKV, including 15% among children aged 0 to 8 years and 37% among children aged 9 to 16 years. The highest force of infection occurred in 2007, 2010, and 2012-2013, with low levels of transmission from 2016 to 2018. A higher proportion of children had evidence of multitypic DENV infection than expected, suggesting high heterogeneity in DENV risk in this setting.

Dengue vaccine acceptability before and after the availability of COVID-19 vaccines in Puerto Rico

Dengue is a growing public health threat, causing approximately 400 million infections annually. In June 2021, the Advisory Committee on Immunization Practices recommended the first dengue vaccine (CYD-TDV) for children aged 9-16 years with a previous dengue infection, living in endemic areas, such as Puerto Rico (PR). As the COVID-19 pandemic affected vaccine intention worldwide, we assessed dengue vaccine intention before (pre-COVID) and after (post-COVID) COVID-19 vaccine availability among participants enrolled in the Communities Organized to Prevent Arboviruses (COPA) cohort to prepare for dengue vaccine implementation in PR. We used logistic regression models to evaluate changes in dengue vaccine intention by interview timing and participant characteristics. Among 2,513 participants pre-COVID, 2,512 answered the dengue vaccine intention question for themselves, and 1,564 answered relative to their children. Post-COVID, dengue vaccine intention in adults increased for themselves from 73.4% to 84.5% (adjusted odds ratio (aOR) = 2.27, 95%CI: 1.90-2.71) and relative to their children from 75.6% to 85.5% (aOR = 2.21, 95%CI: 1.75-2.78). Among all participants, groups with higher dengue vaccine intention included those who reported previous year influenza vaccine uptake and those who reported being frequently bitten by mosquitos, compared to those who did not. Adult males were also more likely to intend to vaccinate themselves than females. Respondents who were employed or in school were less likely to intend to vaccinate compared to those who were not working. The primary reasons for vaccine hesitancy were concerns with side effects and not believing in vaccines, which should be considered during educational strategies prior to dengue vaccine implementation. In general, dengue vaccine intention is high in PR and has increased after COVID-19 vaccine availability, potentially due to increased awareness of vaccine importance during the COVID-19 pandemic.

Community perceptions on challenges and solutions to implement an Aedes aegypti control project in Ponce, Puerto Rico (USA)

This study characterizes community perceptions on a large-scale project seeking to reduce the population of Aedes aegypti mosquitoes and prevent arboviral disease transmission in Ponce, Puerto Rico; and to leverage on these perceptions to make modifications to ensure effective project implementation. In 2017-2018 the team conducted informal interviews, focus groups, and in-depth interviews with leaders and residents of the communities, focusing on challenges and potential solutions to the project implementation. Possible challenges to the project implementation included the lack of geographic consistency between clusters defined by researchers and the participants' description of the communities' geographic boundaries. Few children living in the communities could affect the ability of the project to adequately measure arboviral disease incidence. Also, population attrition due to out-migration, and lack of community leaders and communication channels after Hurricane Maria could affect participation in project activities. Lack of trust on strangers was an important challenge due to criminal activity involving violence and drug use in some community areas. Solutions to the identified challenges included identifying emerging leaders and implementing community meetings to promote project activities. The information that community members provided helped us to understand the natural disasters' impact on population attrition in these communities with a disproportionate impact in younger groups, resulting in an aging population. We identified lack of community organization and leadership and increasing number of abandoned houses that could turn into Aedes aegypti breeding sites. The formative work helped to better define the geographic areas that the study would cover, evaluate the acceptability of innovative vector control methods, and identify communication methods used by residents. With this information, challenges and potential solutions in recruiting participants were anticipated, and the community engagement and communications plans were developed. We recommend selecting clusters before research, because opinions towards mosquito control technologies could vary in added clusters.