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.

The Effectiveness of Social Norm Appeals on Promoting COVID-19 Prevention Behaviors: A Multistudy Examination

Recent research shows social norm perceptions predict people's adherence to COVID-19 preventative health practices. Nonetheless, additional empirical studies are necessary to evaluate the effectiveness of different types of social norm messages on behavioral outcomes with experimental designs. Guided by the social norm literature and frameworks, the current research addresses this need by examining the effects of descriptive and injunctive norm appeals promoting the practice of social distancing and mask-wearing with both a controlled experiment and social media campaigns. Results from this multistudy investigation showed the effectiveness of descriptive and injunctive norm messages (v. no message exposure) in promoting focal behaviors and highlighted the superiority of injunctive norm appeals in promoting behavioral intentions and increasing social media engagement. Theoretical implications and recommendations for practice are discussed.

Aedes aegypti abundance in urban neighborhoods of Maricopa County, Arizona, is linked to increasing socioeconomic status and tree cover

BACKGROUND

Understanding coupled human-environment factors which promote Aedes aegypti abundance is critical to preventing the spread of Zika, chikungunya, yellow fever and dengue viruses. High temperatures and aridity theoretically make arid lands inhospitable for Ae. aegypti mosquitoes, yet their populations are well established in many desert cities.

METHODS

We investigated associations between socioeconomic and built environment factors and Ae. aegypti abundance in Maricopa County, Arizona, home to Phoenix metropolitan area. Maricopa County Environmental Services conducts weekly mosquito surveillance with CO2-baited Encephalitis Vector Survey or BG-Sentinel traps at > 850 locations throughout the county. Counts of adult female Ae. aegypti from 2014 to 2017 were joined with US Census data, precipitation and temperature data, and 2015 land cover from high-resolution (1 m) aerial images from the National Agricultural Imagery Program.

RESULTS

From 139,729 trap-nights, 107,116 Ae. aegypti females were captured. Counts were significantly positively associated with higher socioeconomic status. This association was partially explained by higher densities of non-native landscaping in wealthier neighborhoods; a 1% increase in the density of tree cover around the trap was associated with a ~ 7% higher count of Ae. aegypti (95% CI: 6-9%).

CONCLUSIONS

Many models predict that climate change will drive aridification in some heavily populated regions, including those where Ae. aegypti are widespread. City climate change adaptation plans often include green spaces and vegetation cover to increase resilience to extreme heat, but these may unintentionally create hospitable microclimates for Ae. aegypti. This possible outcome should be addressed to reduce the potential for outbreaks of Aedes-borne diseases in desert cities.

Understanding low COVID-19 booster uptake among US adults

BACKGROUND

Vaccinations against SARS-CoV-2 have consistently been shown to reduce the risk of severe COVID-19 disease. However, uptake of boosters has stalled in the United States at less than 20% of the eligible population. The objective of this study was to assess the reasons for not having obtained a bivalent booster within an existing COVID-19 cohort.

METHODS

A total of 2196 adult participants from the Arizona CoVHORT, a population-based cohort in the United States established in May 2020, who had received at least one dose of the COVID-19 vaccine, responded to surveys administered between February 13 and March 29, 2023 querying receipt of a bivalent booster and if not, the reasons for not receiving it. Descriptive statistics were employed, including frequencies of responses by participant characteristics, and multivariable logistic regression was used to assess the association between participant characteristics and selected themes for not having received the bivalent booster.

RESULTS

The most commonly reported reason for not having been boosted was a prior SARS-CoV-2 infection (39.5%), followed by concern about vaccine side effects (31.5%), believing that the booster would not provide additional protection over the vaccines already received (28.6%), and concern about booster safety (23.4%) or that it would not protect from SARS-CoV-2 infection (23.1%). For themes related to reasons for not having been boosted, those 60 years of age or older were less likely to select items related to knowledge (OR: 0.24; 95% CI: 0.11-0.55) or logistical concerns (OR: 0.09; 95% CI: 0.03-0.30) about the vaccine; while those reporting Hispanic ethnicity were more likely to convey concerns about logistics than those reporting non-Hispanic ethnicity (OR: 2.15; 95% CI: 1.08-4.30). Finally, compared to college graduates, those with some college or technical school were significantly more likely to select items related to the risks and benefits of the bivalent vaccine not being clear as reasons for not having been boosted (OR: 2.41; 95% CI: 1.69-3.43).

CONCLUSIONS

Improvement in booster uptake is necessary for optimal public health in the United States. The development of vaccines against SARS-CoV-2 occurred at an unprecedented speed, but vaccine uptake remains among the greatest current public health challenges as updated boosters continue to be developed and made available to the public. Interventions to improve vaccination rates require a variety of approaches.

Development of a Definition of Postacute Sequelae of SARS-CoV-2 Infection

Importance

SARS-CoV-2 infection is associated with persistent, relapsing, or new symptoms or other health effects occurring after acute infection, termed postacute sequelae of SARS-CoV-2 infection (PASC), also known as long COVID. Characterizing PASC requires analysis of prospectively and uniformly collected data from diverse uninfected and infected individuals.

Objective

To develop a definition of PASC using self-reported symptoms and describe PASC frequencies across cohorts, vaccination status, and number of infections.

Design, Setting, and Participants

Prospective observational cohort study of adults with and without SARS-CoV-2 infection at 85 enrolling sites (hospitals, health centers, community organizations) located in 33 states plus Washington, DC, and Puerto Rico. Participants who were enrolled in the RECOVER adult cohort before April 10, 2023, completed a symptom survey 6 months or more after acute symptom onset or test date. Selection included population-based, volunteer, and convenience sampling.

Exposure

SARS-CoV-2 infection.

Main Outcomes and Measures

PASC and 44 participant-reported symptoms (with severity thresholds).

Results

A total of 9764 participants (89% SARS-CoV-2 infected; 71% female; 16% Hispanic/Latino; 15% non-Hispanic Black; median age, 47 years [IQR, 35-60]) met selection criteria. Adjusted odds ratios were 1.5 or greater (infected vs uninfected participants) for 37 symptoms. Symptoms contributing to PASC score included postexertional malaise, fatigue, brain fog, dizziness, gastrointestinal symptoms, palpitations, changes in sexual desire or capacity, loss of or change in smell or taste, thirst, chronic cough, chest pain, and abnormal movements. Among 2231 participants first infected on or after December 1, 2021, and enrolled within 30 days of infection, 224 (10% [95% CI, 8.8%-11%]) were PASC positive at 6 months.

Conclusions and Relevance

A definition of PASC was developed based on symptoms in a prospective cohort study. As a first step to providing a framework for other investigations, iterative refinement that further incorporates other clinical features is needed to support actionable definitions of PASC.

Differences in Longevity and Temperature-Driven Extrinsic Incubation Period Correlate with Varying Dengue Risk in the Arizona–Sonora Desert Region

Dengue transmission is determined by a complex set of interactions between the environment, Aedes aegypti mosquitoes, dengue viruses, and humans. Emergence in new geographic areas can be unpredictable, with some regions having established mosquito populations for decades without locally acquired transmission. Key factors such as mosquito longevity, temperature-driven extrinsic incubation period (EIP), and vector–human contact can strongly influence the potential for disease transmission. To assess how these factors interact at the edge of the geographical range of dengue virus transmission, we conducted mosquito sampling in multiple urban areas located throughout the Arizona–Sonora desert region during the summer rainy seasons from 2013 to 2015. Mosquito population age structure, reflecting mosquito survivorship, was measured using a combination of parity analysis and relative gene expression of an age-related gene, SCP-1. Bloodmeal analysis was conducted on field collected blood-fed mosquitoes. Site-specific temperature was used to estimate the EIP, and this predicted EIP combined with mosquito age were combined to estimate the abundance of “potential” vectors (i.e., mosquitoes old enough to survive the EIP). Comparisons were made across cities by month and year. The dengue endemic cities Hermosillo and Ciudad Obregon, both in the state of Sonora, Mexico, had higher abundance of potential vectors than non-endemic Nogales, Sonora, Mexico. Interestingly, Tucson, Arizona consistently had a higher estimated abundance of potential vectors than dengue endemic regions of Sonora, Mexico. There were no observed city-level differences in species composition of blood meals. Combined, these data offer insights into the critical factors required for dengue transmission at the ecological edge of the mosquito’s range. However, further research is needed to integrate an understanding of how social and additional environmental factors constrain and enhance dengue transmission in emerging regions.

COVID-19 vaccination and changes in the menstrual cycle among vaccinated persons

OBJECTIVE

To describe the characteristics of people who experience changes to their menstrual cycle after COVID-19 vaccination.

DESIGN

Longitudinal study.

PATIENT(S)

We recruited a volunteer sample with and without a history of SARS-CoV-2 infection who enrolled in the Arizona COVID-19 Cohort (CoVHORT) study and participated in a reproductive sub-cohort who were pre-menopausal, not pregnant, and had received a COVID-19 vaccine in 2021 (n = 545).

EXPOSURE(S)

Demographic and reproductive characteristics were collected via self-reports.

MAIN OUTCOME MEASURE(S)

Information on self-reported changes in the menstrual cycle after COVID-19 vaccination was collected from May 2021 to December 2021. We looked at demographic and reproductive characteristics as predictors of menstrual cycle change.

RESULT(S)

The majority of our vaccinated sample received the Pfizer-BioNTech vaccine (58%), and were 26-35 years old (51%), non-Hispanic (84%), and White (88%). Approximately 25% of vaccinated participants reported a change in their menstrual cycle after vaccination; the majority reported changes after their second dose (56%) as compared with their first (18%) and third (14%) doses. The most commonly reported changes were irregular menstruation (43%), increased premenstrual symptoms (34%), increased menstrual pain or cramps (30%), and abnormally heavy or prolonged bleeding (31%). High self-reported perceived stress levels compared with low perceived stress (OR, 2.22; 95% CI 1.12-4.37) and greater body mass index (OR, 1.04; 95% CI 1.00-1.07) were associated with greater odds of experiencing the menstrual cycle changes after the vaccination. Participants having a history of SARS-CoV-2 infection were less likely to report changes in their menstrual cycle after vaccination compared with the participants with no history of SARS-CoV-2 infection (OR, 0.58; 95% CI 0.32-1.04).

CONCLUSION(S)

Among vaccinated participants, approximately 25% of them reported predominantly temporary changes in the menstrual cycle, however, we are unable to determine whether these changes are due to normal cycle variability. The COVID-19 vaccines are safe and effective for everyone, including pregnant people and people trying to conceive; hence, these findings should not discourage vaccination.

Self-Reported Symptoms at Last Febrile Illness as a Predictor of Treatment-Seeking in Western Kenya: A Cross-Sectional Study

Timely treatment-seeking behavior can reduce morbidity and mortality due to infectious diseases. Patterns of treatment-seeking behavior can differ by access to health care, and perceptions of disease severity and symptoms. We evaluated the association between self-reported symptoms at last illness and the level of treatment-seeking behaviors. We analyzed cross-sectional data from 1,037 participants from the lowlands and highlands of Western Kenya from 2015 using logistic regression models. There was considerable heterogeneity in the symptoms and treatment-seeking behaviors reported among individuals who were febrile at their last illness. A greater number of self-reported categories of symptoms tended to be associated with a higher likelihood of treatment-seeking in both sites. Participants were significantly more likely to seek treatment if they reported fever, aches, and digestive symptoms at last illness than just fever and aches or fever alone, but the frequency of treatment-seeking for fever in combination with aches and respiratory symptoms did not follow a consistent pattern. Among those who sought treatment, most used a formal source, but the patterns were inconsistent across sites and by the number of symptoms categories. Understanding the drivers of treatment-seeking behavior after febrile illness is important to control and treat infectious diseases in Kenya.

Global city densities: Re-examining urban scaling theory

Understanding scaling relations of social and environmental attributes of urban systems is necessary for effectively managing cities. Urban scaling theory (UST) has assumed that population density scales positively with city size. We present a new global analysis using a publicly available database of 933 cities from 38 countries. Our results showed that (18/38) 47% of countries analyzed supported increasing density scaling (pop ~ area) with exponents ~⅚ as UST predicts. In contrast, 17 of 38 countries (~45%) exhibited density scalings statistically indistinguishable from constant population densities across cities of varying sizes. These results were generally consistent in years spanning four decades from 1975 to 2015. Importantly, density varies by an order of magnitude between regions and countries and decreases in more developed economies. Our results (i) point to how economic and regional differences may affect the scaling of density with city size and (ii) show how understanding country- and region-specific strategies could inform effective management of urban systems for biodiversity, public health, conservation and resiliency from local to global scales.

200 word statement of contribution: Urban Scaling Theory (UST) is a general scaling framework that makes quantitative predictions for how many urban attributes spanning physical, biological and social dimensions scale with city size; thus, UST has great implications in guiding future city developments. A major assumption of UST is that larger cities become denser. We evaluated this assumption using a publicly available global dataset of 933 cities in 38 countries. Our scaling analysis of population size and area of cities revealed that while many countries analyzed showed increasing densities with city size, about 45% of countries showed constant densities across cities. These results question a key assumption of UST. Our results suggest policies and management strategies for biodiversity conservation, public health and sustainability of urban systems may need to be tailored to national and regional scaling relations to be effective.

Design and implementation of a health messaging protocol employed for use within a COVID-19 health dissemination platform

Introduction

AZCOVIDTXT, a bilingual, two-way information sharing platform was created in April of 2020 in response to rising COVID-19 cases in Arizona. The aim of this paper is to delineate the protocol and processes used to develop and disseminate health messaging to serve as guidance for other groups, universities, or public health programs in the implementation or enhancement of health communication services.

Methods

Health messaging formats included website articles, published on the system's website (azcovidtxt.org), infographics posted on social media, and SMS. Social media and SMS infographics were intended to highlight and augment the topics covered in the weekly website articles, to create a seamless multimodal source of reliable COVID-19 information for AZCOVIDTXT enrollees and the broader public. All health messaging information, text message and social media content was planned and reviewed collaboratively by the AZCOVIDTXT team topic experts for accuracy, efficacy, and content consistency.

Results

As of July 2021, AZCOVIDTXT provided weekly COVID-19-related health communication to 3,747 participating households located across 225 Arizona zip codes. AZCOVIDTXT has developed and sent 446 unique, bilingual SMS for a total of 271,977 contact points. The team has produced and published 179 website articles, which averaged a combined 7,000-page views per month, and 173 social media posts were made available to 268 followers across three platforms.

Discussion

Several programmatic aspects were deemed essential to the success of AZCOVIDTXT. These included (1) addressing community specific needs, (2) creating timely and relevant content, (3) developing an adaptable system, and (4) prioritizing system automation where possible, (5) having an interdisciplinary team approach to identifying and crafting key messages.

COVID-19 lockdowns: Employment and business disruptions, water access and hygiene practices in Nairobi's informal settlements

Host to one billion people around the world, informal settlements are especially vulnerable to COVID-19 lockdown measures as they already lack basic services such as water, toilets, and secure housing. Additionally, many residents work in informal labor markets that have been affected by the lockdowns, resulting in further reductions in access to resources, including clean water. This study uses a cross-sectional design (n = 532) to examine the vulnerabilities of households to employment and business disruptions, water access and hygiene practices during the COVID-19 lockdowns between April and June 2020 in three informal settlements in Nairobi, Kenya. We used survey questions from the Household Water Insecurity Experience Scale (HWISE) to investigate the relationship between employment and business disruptions, water access, and hygiene practices (i.e., hand washing, body washing, clothes washing, and being able to use or drink clean water). Of the sampled households, 96% were forced to reduce work hours during the lockdowns, and these households had 92% lower odds of being able to afford water than households who did not experience a work hour reduction (OR = 0.08, p < .001). Household challenges in affording water were likely due to a combination of reduced household income, increased water prices, and pre-existing poverty, and were ultimately associated with lower hygiene scores (Beta = 1.9, p < .001). Our results highlight a compounding tragedy of reduced water access in informal settlements that were already facing water insecurities at a time when water is a fundamental requirement for following hygiene guidelines to reduce disease burden during an ongoing pandemic. These outcomes emphasize the need for targeted investments in permanent water supply infrastructures and improved hygiene behaviors as a public health priority among households in informal settlements.

Outdoor Activity Associated with Higher Self-Reported Emotional Well-Being During COVID-19

Shifts in activity patterns during the COVID-19 pandemic might have impacted the benefits of outdoor activities for mental health. By leveraging an existing mobile application, we collected self-reported data on daily outdoor activities, emotional well-being, and the influence of COVID-19 on participant's outdoor activity levels during April-July 2020. Individuals reporting outdoor activities, in greenspaces or in their residence, had higher well-being scores and this effect increased with age. Self-reported impacts of COVID-19 on emotional well-being were associated with lower well-being scores. This work suggests that outdoor activities may have improved mental health during the COVID-19 pandemic.

A Rasch analysis assessing the reliability and validity of the Arizona CoVHORT COVID-19 vaccine questionnaire

Background

Despite the widespread availability of COVID-19 vaccines in the United States, many that have chosen not to be vaccinated have done so because of vaccine hesitancy. This highlights the need for tools that accurately capture the knowledge, attitudes, and beliefs towards COVID-19 vaccines, and provide steps toward improving vaccine acceptance.

Methods

Participants of the Arizona CoVHORT (COVID-19 Cohort) received a one-time, electronic based cross-sectional questionnaire intended to capture underlying motivations regarding vaccination, as well as hesitations that may prevent people from getting vaccinated. Rasch analysis was conducted among 4703 CoVHORT participants who had completed the vaccine questionnaire to assess questionnaire reliability and validity. Response categories were grouped to optimize scale functioning and to ensure independent probabilities of participant endorsement.

Results

A total of 4703 CoVHORT participants completed the questionnaire, of whom 68% were female, and who had a mean age of 48 years. Participants were primarily White (90%), highly educated (63% with a college degree or above, with most respondents (45%) having an income of more than $75,000 per annum. The results indicated the questionnaire has good reliability and construct validity for assessing attitudes and beliefs about the COVID-19 vaccines. In-fit mean-squares for included items ranged from 0.61 to 1.72 and outfit mean-squares ranged from 0.56 to 1.75, and correlation coefficients ranged from 0.25 to 0.75. The person-item map indicated normal distribution of logit scores measuring perceptions about COVID-19 vaccinations.

Conclusions

The CoVHORT vaccine questionnaire demonstrated satisfactory reliability and construct validity in assessing attitudes and beliefs about COVID-19 vaccines. Overall results provide a starting point for a reliable and valid tool to assess knowledge and perceptions about COVID-19 vaccination, ultimately providing public health professionals with an instrument to assess the factors that are associated with vaccine acceptance or hesitancy.

COVID-19 Infection, the COVID-19 Pandemic, and Changes in Sleep

The objective of this study was to investigate the differences in sleep patterns among individuals with and without laboratory-confirmed SARS-CoV-2 infection. Laboratory-confirmed SARS-CoV-2 test results and self-reported measures recalling sleep habits prior to and during the pandemic were collected from May 2020 to March 2021 among 1,848 individuals in The Arizona CoVHORT Study. We used linear and logistic regression to model the association between test status, presentation of symptoms, and time since test result with sleep duration and trouble sleeping, respectively. Mixed models were used to investigate change in sleep duration prior to the pandemic compared to during the pandemic. Overall, 16.2% of the sample were SARS-CoV-2 positive, 64.3% were SARS-CoV-2 negative, and 19.5% were untested for SARS-CoV-2. Independent of SARS-CoV-2 infection status, all participants slept longer during the pandemic compared to pre-pandemic (Δ SARS-CoV-2 positive: 77.7 min, 95% CI 67.9, 87.5; Δ SARS-CoV-2 negative: 13.4 min, 95% CI 8.4, 18.3). However, SARS-CoV-2 positive participants slept 60.9 min longer (95% CI 49.1, 72.8) than SARS-CoV-2 negative participants in multivariable-adjusted models and had greater odds of trouble sleeping three or more times per week since the start of the pandemic (OR: 1.34 95% CI 1.02, 1.77) This greater odds of trouble sleeping persisted for participants who reported sleep habits > 30 days after their positive SARS-CoV-2 (OR: 2.11 95% CI 1.47, 3.03). Sleep patterns among non-hospitalized individuals with COVID-19 were altered following infection, regardless of the presentation of symptoms and time since infection.

Elucidating symptoms of COVID-19 illness in the Arizona CoVHORT: a longitudinal cohort study

OBJECTIVE

To elucidate the symptoms of laboratory-confirmed COVID-19 cases as compared with laboratory-confirmed negative individuals and to the untested general population among all participants who reported symptoms within a large prospective cohort study.

SETTING AND DESIGN

This work was conducted within the framework of the Arizona CoVHORT, a longitudinal prospective cohort study conducted among Arizona residents.

PARTICIPANTS

Eligible participants were any individual living in Arizona and were recruited from across Arizona via COVID-19 case investigations, participation in testing studies and a postcard mailing effort.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome measure was a comparison of the type and frequency of symptoms between COVID-19-positive cases, tested but negative individuals and the general untested population who reported experiencing symptoms consistent with COVID-19.

RESULTS

Of the 1335 laboratory-confirmed COVID-19 cases, 180 (13.5%) reported having no symptoms. Of those that did report symptoms, the most commonly reported were fatigue (82.2%), headache (74.6%), aches, pains or sore muscles (66.3%), loss of taste or smell (62.8) and cough (61.9%). In adjusted logistic regression models, COVID-19-positive participants were more likely than negative participants to experience loss of taste and smell (OR 12.1; 95% CI 9.6 to 15.2), bone or nerve pain (OR 3.0; 95% CI 2.2 to 4.1), headache (OR 2.6; 95% CI 2.2 to 3.2), nausea (OR 2.4; 95% CI 1.9 to 3.1) or diarrhoea (OR 2.1; 95% CI 1.7 to 2.6). Fatigue (82.9) and headache (74.9) had the highest sensitivities among symptoms, while loss of taste or smell (87.2) and bone or nerve pain (92.9) had the high specificities among significant symptoms associated with COVID-19.

CONCLUSION

When comparing confirmed COVID-19 cases with either confirmed negative or untested participants, the pattern of symptoms that discriminates SARS-CoV-2 infection from those arising from other potential circulating pathogens may differ from general reports of symptoms among cases alone.

Knowledge, attitudes, and practices of Anopheles mosquito control through insecticide treated nets and community-based health programs to prevent malaria in East Sumba Island, Indonesia

With an estimated 241 million human cases and 627,000 deaths in 2020, malaria remains a significant and ongoing global health challenge. This study employs a qualitative approach to investigate knowledge, attitudes, and practices surrounding mosquito control and prevention methods in East Sumba Regency, Indonesia. While malaria is under control in much of Indonesia, transmission in Sumba Island remains high, with incidence as high as 500 per 1000 population in some areas. A qualitative study was undertaken to explore use of insecticide treated nets, (ITNs), traditional Sumbanese mosquito control methods, and the role of women, integrated health service posts, (posyandu) and community-based health workers (kaders) in combatting malaria and controlling mosquitoes. Focus group discussions (n = 7) were conducted in East Sumba Island stratified by urban/rural location and level of malaria transmission. Key informant interviews (n = 14) were conducted with religious leaders, health workers, and women's group leaders. Results indicate that environmental conditions, such as high temperatures, were common deterrents to regular ITN use. Furthermore, our results suggest that community embedded health workers, kaders, and health service posts, posyandu, play an important role in information dissemination related to mosquitoes and mosquito-borne diseases as well as the distribution and use of ITNs in East Sumba Island. The role of the posyandu and kaders could be expanded to improve malaria prevention by integration with educational campaigns, aiding ITN distributions, and malaria diagnosis and treatment. This study is the first to examine mosquito-borne disease-related knowledge, attitudes, and practices in East Sumba Island, Indonesia. Results could improve mosquito control and malaria prevention by providing insights into local knowledge of Anopheles mosquitoes and malaria as well. Tailoring mosquito control and malaria prevention strategies around local knowledge and perceptions is likely to be more acceptable and sustainable.

Quantifying SARS-CoV-2 Infection Risk Within the Google/Apple Exposure Notification Framework to Inform Quarantine Recommendations

Most early Bluetooth-based exposure notification apps use three binary classifications to recommend quarantine following SARS-CoV-2 exposure: a window of infectiousness in the transmitter, ≥15 minutes duration, and Bluetooth attenuation below a threshold. However, Bluetooth attenuation is not a reliable measure of distance, and infection risk is not a binary function of distance, nor duration, nor timing. We model uncertainty in the shape and orientation of an exhaled virus-containing plume and in inhalation parameters, and measure uncertainty in distance as a function of Bluetooth attenuation. We calculate expected dose by combining this with estimated infectiousness based on timing relative to symptom onset. We calibrate an exponential dose-response curve based on infection probabilities of household contacts. The probability of current or future infectiousness, conditioned on how long postexposure an exposed individual has been symptom-free, decreases during quarantine, with shape determined by incubation periods, proportion of asymptomatic cases, and asymptomatic shedding durations. It can be adjusted for negative test results using Bayes' theorem. We capture a 10-fold range of risk using six infectiousness values, 11-fold range using three Bluetooth attenuation bins, ∼sixfold range from exposure duration given the 30 minute duration cap imposed by the Google/Apple v1.1, and ∼11-fold between the beginning and end of 14 day quarantine. Public health authorities can either set a threshold on initial infection risk to determine 14-day quarantine onset, or on the conditional probability of current and future infectiousness conditions to determine both quarantine and duration.

Prevalence and risk factors for SARS-CoV-2 infection in children with and without symptoms seeking care in Managua, Nicaragua: results of a cross-sectional survey

OBJECTIVE

This study aimed to capture key epidemiological data on SARS-CoV-2 infection in Nicaraguan children (≤18 years) seeking medical care, between 6 October and 16 November 2020.

DESIGN

In this cross-sectional study, 418 children were recruited: 319 with symptoms characteristic of COVID-19 and 99 with no symptoms of illness. Children were tested for SARS-CoV-2 RNA using loop-mediated isothermal amplification. A questionnaire was employed to identify symptoms, risk factors, comorbidities and COVID-19 prevention measures.

SETTING

Research was carried out in four hospitals and two clinics in Managua, Nicaragua, where schools and businesses remained open throughout the COVID-19 pandemic.

PARTICIPANTS

Children were enrolled into a possible COVID-19 group if presenting with clinical symptoms. A comparison group included children lacking any COVID-19 symptoms attending routine check-ups or seeking care for issues unrelated to COVID-19.

RESULTS

A high prevalence (43%) of SARS-CoV-2 infection was found, which was relatively equivalent in symptomatic and non-symptomatic children. Age distribution was similar between symptomatic and non-symptomatic children testing positive for SARS-CoV-2. Symptomatic children who tested positive for SARS-CoV-2 were 2.7 times more likely to have diarrhoea (26.7% in positive vs 12.0% in negative; OR=2.7 (95% CI 1.5 to 4.8), p=0.001) and were 2.0 times more likely to have myalgia (17.8% in positive vs 9.8% in negative; OR=2.0 (95% CI 1.0 to 3.8), p=0.04). Children with COVID-19 symptoms, who tested positive for SARS-CoV-2, were more likely to be under age 5 years and to have a pre-existing comorbid condition than children who tested positive but did not have symptoms.

CONCLUSIONS

This is the first paediatric study to provide laboratory-confirmed data on SARS-CoV-2 infection in Nicaragua, crucial for paediatric health services planning and a successful COVID-19 response. The high prevalence of the virus suggests widespread and sustained community transmission, underscoring the urgent need for robust data on the true extent of SARS-CoV-2 infection throughout Nicaragua.

The Complex Epidemiological Relationship between Flooding Events and Human Outbreaks of Mosquito-Borne Diseases: A Scoping Review

BACKGROUND

Climate change is expected to increase the frequency of flooding events. Although rainfall is highly correlated with mosquito-borne diseases (MBD) in humans, less research focuses on understanding the impact of flooding events on disease incidence. This lack of research presents a significant gap in climate change-driven disease forecasting.

OBJECTIVES

We conducted a scoping review to assess the strength of evidence regarding the potential relationship between flooding and MBD and to determine knowledge gaps.

METHODS

PubMed, Embase, and Web of Science were searched through 31 December 2020 and supplemented with review of citations in relevant publications. Studies on rainfall were included only if the operationalization allowed for distinction of unusually heavy rainfall events. Data were abstracted by disease (dengue, malaria, or other) and stratified by post-event timing of disease assessment. Studies that conducted statistical testing were summarized in detail.

RESULTS

From 3,008 initial results, we included 131 relevant studies (dengue n = 45 , malaria n = 61 , other MBD n = 49 ). Dengue studies indicated short-term (< 1  month ) decreases and subsequent (1-4 month) increases in incidence. Malaria studies indicated post-event incidence increases, but the results were mixed, and the temporal pattern was less clear. Statistical evidence was limited for other MBD, though findings suggest that human outbreaks of Murray Valley encephalitis, Ross River virus, Barmah Forest virus, Rift Valley fever, and Japanese encephalitis may follow flooding.

DISCUSSION

Flooding is generally associated with increased incidence of MBD, potentially following a brief decrease in incidence for some diseases. Methodological inconsistencies significantly limit direct comparison and generalizability of study results. Regions with established MBD and weather surveillance should be leveraged to conduct multisite research to a) standardize the quantification of relevant flooding, b) study nonlinear relationships between rainfall and disease, c) report outcomes at multiple lag periods, and d) investigate interacting factors that modify the likelihood and severity of outbreaks across different settings. https://doi.org/10.1289/EHP8887.

How deregulation, drought and increasing fire impact Amazonian biodiversity

Biodiversity contributes to the ecological and climatic stability of the Amazon Basin^1,2, but is increasingly threatened by deforestation and fire^3,4. Here we quantify these impacts over the past two decades using remote-sensing estimates of fire and deforestation and comprehensive range estimates of 11,514 plant species and 3,079 vertebrate species in the Amazon. Deforestation has led to large amounts of habitat loss, and fires further exacerbate this already substantial impact on Amazonian biodiversity. Since 2001, 103,079-189,755 km² of Amazon rainforest has been impacted by fires, potentially impacting the ranges of 77.3-85.2% of species that are listed as threatened in this region⁵. The impacts of fire on the ranges of species in Amazonia could be as high as 64%, and greater impacts are typically associated with species that have restricted ranges. We find close associations between forest policy, fire-impacted forest area and their potential impacts on biodiversity. In Brazil, forest policies that were initiated in the mid-2000s corresponded to reduced rates of burning. However, relaxed enforcement of these policies in 2019 has seemingly begun to reverse this trend: approximately 4,253-10,343 km² of forest has been impacted by fire, leading to some of the most severe potential impacts on biodiversity since 2009. These results highlight the critical role of policy enforcement in the preservation of biodiversity in the Amazon.

Post-acute sequelae of COVID-19 in a non-hospitalized cohort: Results from the Arizona CoVHORT

Clinical presentation, outcomes, and duration of COVID-19 has ranged dramatically. While some individuals recover quickly, others suffer from persistent symptoms, collectively known as long COVID, or post-acute sequelae of SARS-CoV-2 (PASC). Most PASC research has focused on hospitalized COVID-19 patients with moderate to severe disease. We used data from a diverse population-based cohort of Arizonans to estimate prevalence of PASC, defined as experiencing at least one symptom 30 days or longer, and prevalence of individual symptoms. There were 303 non-hospitalized individuals with a positive lab-confirmed COVID-19 test who were followed for a median of 61 days (range 30-250). COVID-19 positive participants were mostly female (70%), non-Hispanic white (68%), and on average 44 years old. Prevalence of PASC at 30 days post-infection was 68.7% (95% confidence interval: 63.4, 73.9). The most common symptoms were fatigue (37.5%), shortness-of-breath (37.5%), brain fog (30.8%), and stress/anxiety (30.8%). The median number of symptoms was 3 (range 1-20). Amongst 157 participants with longer follow-up (≥60 days), PASC prevalence was 77.1%.

Design of the Arizona CoVHORT: A Population-Based COVID-19 Cohort

This study is a prospective, population-based cohort of individuals with a history of SARS-CoV-2 infection and those without past infection through multiple recruitment sources. The main study goal is to track health status over time, within the diverse populations of Arizona and to identify the long-term consequences of COVID-19 on health and well-being. A total of 2,881 study participants (16.2% with a confirmed SARS-CoV-2 infection) have been enrolled as of December 22, 2020, with a target enrollment of 10,000 participants and a planned follow-up of at least 2 years. This manuscript describes a scalable study design that utilizes a wide range of recruitment sources, leveraging electronic data collection to capture and link longitudinal participant data on the current and emerging issues associated with the COVID-19 pandemic. The cohort is built within a collaborative infrastructure that includes new and established partnerships with multiple stakeholders, including the state's public universities, local health departments, tribes, and tribal organizations. Challenges remain for ensuring recruitment of diverse participants and participant retention, although the electronic data management system and timing of participant contact can help to mitigate these problems.

Knowledge, Attitudes, and Practices Related to Rocky Mountain Spotted Fever in Hermosillo, México

Rocky Mountain spotted fever (RMSF) is a serious disease in northwest Mexico, particularly in low-income communities. This study aimed to evaluate RMSF-related knowledge, attitudes, and practices in an endemic urban area with a high burden of the disease. A cross-sectional study design using a non-probabilistic household survey was conducted with 400 residents in Hermosillo, Mexico. Primary themes assessed included dog and tick-related exposure, RMSF knowledge, healthcare-seeking behavior, sociodemographic data, and household information. The majority (59%) of those surveyed had heard about RMSF, although only 36% of RMSF-aware respondents knew any RMSF symptoms. Among RMSF-aware respondents, 26% did not know or were unsure of prevention strategies. Individuals in the low socioeconomic status (SES) stratum were less likely to have heard about RMSF (odds ratio [OR]: 0.39; 95% CI: 0.25-0.59), use dog collars or any other product to avoid ticks (OR: 0.40; 95% CI: 0.17-0.99), or check their dogs for ticks (OR: 0.25; 95% CI: 0.09-0.74). The likelihood of observing high numbers of free-roaming dogs in their neighborhood was four times higher in the low SES stratum (OR: 4.19; 95% CI: 2.10-8.38) than in the high SES stratum. These findings emphasize the need for an integrative community approach to improve early recognition of symptoms and knowledge of prevention strategies, particularly in low SES neighborhoods.

"After those nets are torn, most people use them for other purposes": an examination of alternative bed net use in western Kenya

BACKGROUND

Alternative long-lasting insecticidal net (LLIN) use for purposes other than sleeping protection from mosquitoes is widely debated as a limitation to successful malaria control efforts, yet rarely rigorously studied.

METHODS

A cross-sectional survey of 1217 households in an epidemic highland site and an endemic lowland site in western Kenya collected information on alternative use in three ways: direct observations, participant self-report, and participant reporting of community-level practices. LLIN misuse was defined as use of an intact net for alternative purposes and repurposing as alternatively using an old or damaged net. Associations between households with observed repurposed nets and universal access and household net use were examined.

RESULTS

Households describe repurposing nets when they are torn and/or old. Repurposed nets were observed in 8.1% (52/643) highlands households and 33.0% (184/574) lowlands households. Repurposed nets served as chicken coops (33% highlands, 20% lowlands), fences (37% highlands, 25% lowlands), tree covers (22% lowlands), curtains (3% highlands), covering bathrooms (1.5% highlands, 9% lowlands), and washing sponges (13% lowlands). No association was found between repurposing and universal access or household net use. Misuse was rare. Of 379 repurposed nets, 4 (1.06%) were in good condition with no holes. Of 1,758 active nets, 13 (0.74%) were misused.

CONCLUSIONS

Alternative net use in this study involved repurposing rather than misuse. Repurposing was not detrimental to malaria prevention efforts in these communities. Standardized measurement of alternative net use should be used to better understand the practice and its potential impact on the success of malaria interventions.

Size as a Proxy for Survival in Aedes aegypti (Diptera: Culicidae) Mosquitoes

The Aedes aegypti mosquito is the primary vector of dengue, yellow fever, chikungunya, and Zika viruses. Infection with the dengue virus alone occurs in an estimated 400 million people each year. Likelihood of infection with a virus transmitted by Ae. aegypti is most commonly attributed to abundance of the mosquito. However, the Arizona-Sonora desert region has abundant Ae. aegypti in most urban areas, yet local transmission of these arboviruses has not been reported in many of these cities. Previous work examined the role of differential Ae. aegypti longevity as a potential explanation for these discrepancies in transmission. To determine factors that were associated with Ae. aegypti longevity in the region, we collected eggs from ovitraps in Tucson, AZ and reared them under multiple experimental conditions in the laboratory to examine the relative impact of temperature and crowding during development, body size, fecundity, and relative humidity during the adult stage. Of the variables studied, we found that the combination of temperature during development, relative humidity, and body size produced the best model to explain variation in age at death. El mosquito Aedes aegypti es el vector primario de los virus de dengue, fiebre amarilla, chikungunya y Zika. Solamente las infecciones con los virus de dengue ocurren en aproximadamente 400 millones de personas cada año. La probabilidad de infección con un virus transmitido por Ae. aegypti es frecuentemente atribuido a la abundancia del mosquito. No obstante, la región del desierto de Arizona-Sonora tiene una abundancia de Ae. aegypti en la mayoría de las áreas urbanas, pero la transmisión local de estos arbovirus no ha sido reportada en muchas de estas ciudades. Trabajos previos han examinado el rol de las diferencias de longevidad en Ae. aegypti como explicación potencial por estas discrepancias en la transmisión. Para determinar que factores fueron asociados con longevidad en Ae. aegypti en la región, colectamos huevos de ovitrampas en Tucson, Arizona y los criamos debajo de múltiples condiciones experimentales en el laboratorio para examinar el impacto relativo de temperatura y competencia para nutrición durante desarrollo, tamaño del cuerpo, capacidad reproductiva, y humedad relativa durante adultez. De las variables estudiados, encontramos que la combinación de temperatura durante desarrollo, humedad relativa, y tamaño del cuerpo produjo el mejor modelo para explicar variación en edad al tiempo de la muerte.

Insufficient Ratio of Long-Lasting Insecticidal Nets to Household Members Limited Universal Usage in Western Kenya: A 2015 Cross-Sectional Study

Universal "coverage" with long-lasting insecticidal nets (LLINs) is recommended for malaria control in endemic areas, but ownership does not ensure usage. We evaluated relationships between household-level ownership and individual-level usage in western Kenya in 2015. Low-prevalence highland (> 1,500 m) and highly endemic lowland (< 1,200 m) sites were surveyed from July to August 2015. Household members reported long-lasting insecticidal net ownership, use, and barriers to use. Net ownership was categorized as sufficient (≤ 2 people/net), insufficient (> 2 people/net), or none. Each LLIN was assumed to provide access to two people. We surveyed 574 lowland and 643 highland households, with 1,677 and 2,742 members, respectively. More than 98% of lowland households owned LLIN(s); 72.1% owned a sufficient number. Only 37.5% of highland households had sufficient nets. More people used LLINs than were estimated to have access in the lowlands (94.2% versus 85.3%), but proportions were similar in the highlands (54.3% versus 53.3%). Insufficient ownership was most common for larger households in both areas and strongly predicted LLIN usage. In households with insufficient nets, men, school-age children (aged 5-15 years), and nonnuclear family members were less likely to use LLINs; only relationship to the head of the household significantly predicted use in households with sufficient nets. Long-lasting insecticidal nets were widespread in western Kenya in 2015, but insufficient household ownership remained common in the epidemic highlands and in large households. Access seemed to be the primary driver of individual use. To interrupt transmission, LLIN campaigns should improve distribution to large households and promote use among men, school-age children, and nonnuclear family members.

Women's Health Perceptions and Beliefs Related to Zika Virus Exposure during the 2016 Outbreak in Northern Brazil

During the 2016 Zika pandemic in Brazil, women's perceptions of infection risk, ability to adhere to Zika prevention strategies, or access to services following exposure were not emphasized in the public health response. Women in Fortaleza, Brazil, responded to a questionnaire on social factors related to perceived Zika risk and access to health care in June 2016. Data were coded using prespecified categories, and response frequency was reported. Of 37 respondents, most reported a lack of public services to support mosquito control (n = 19) or delayed access to reproductive health care (n = 14). Only 22% described specific maternal risks or fetal outcomes as a consequence of Zika infection. Respondents indicated an overall disconnect between public health efforts and women's perceptions of their reproductive control, including limited support concerning microcephaly in infants. Interventions targeting Zika may require a greater emphasis on strengthening health systems and infrastructure to realistically prevent transmission.

Malaria education interventions addressing bed net care and repair practices: a systematic review

Education intervention effectiveness to improve bed net care and repair knowledge or practices is unclear. To assess intervention effectiveness, we systematically reviewed eight peer-reviewed literature databases and 16 malaria organizations (PROSPERO protocol CRD42019123932) using pre-specified combinations of 'education intervention', 'mosquito net', and 'malaria' search terms. Data were abstracted for 29 of 43 studies meeting inclusion criteria, of which 16 studies included education as amain focus. Of these 16, there was evidence of intervention effectiveness among half of the studies, which reported improvements in knowledge or practices, while four had mixed results, and four had unclear results. Overall there is no clear conclusion regarding the effectiveness of education interventions to improve net care and repair, though some instructional methods suggest more success than others. Interventions used combinations of instructional methods; passive mass education (6), active mass education (12), and interpersonal methods (8). Interventions combining mass and interpersonal methods resulted in positive improvements (four positive, one mixed). We found no evidence that interventions grounded in health behavior theory achieved more positive results than those not grounded in theory, potentially because net care education was typically asecondary objective. Of 289 gray literature results, 286 (99%) were net distribution reports from Against Malaria Foundation describing 136 distributions; eighty of which (58.8%) mentioned no education related to net care and repair. We found lack of involvement of experts in education among included interventions. Involving trained instructors with expertise in education theory and instructional strategies may improve instruction quality to yield more effective interventions.

A Simple Model to Predict the Potential Abundance of Aedes aegypti Mosquitoes One Month in Advance

The mosquito Aedes (Stegomyia) aegypti (L.) is the primary vector of dengue, chikungunya, and Zika viruses in the United States. Surveillance for adult Ae. aegypti is limited, hindering understanding of the mosquito's seasonal patterns and predictions of areas at elevated risk for autochthonous virus transmission. We developed a simple, intuitive empirical model that uses readily available temperature and humidity variables to predict environmental suitability for low, medium, or high potential abundance of adult Ae. aegypti in a given city 1 month in advance. Potential abundance was correctly predicted in 73% of months in arid Phoenix, AZ (over a 10-year period), and 63% of months in humid Miami, FL (over a 2-year period). The monthly model predictions can be updated daily, weekly, or monthly and thus may be applied to forecast suitable conditions for Ae. aegypti to inform vector-control activities and guide household-level actions to reduce mosquito habitat and human exposure.

Bed net care practices and associated factors in western Kenya

Background

Insecticide-treated nets (ITNs) and long-lasting insecticidal nets (LLINs) are effective for malaria prevention and are designed to provide nearly 5 years of mosquito protection. However, many ITNs and LLINs become damaged and ineffective for mosquito bite prevention within 1 to 2 years in field conditions. Non-adherence to recommended bed net care and repair practices may partially explain this shortened net longevity.

Methods

Using data from a cross-sectional study, a net care adherence score was developed and adherence to net care practices described from two regions of western Kenya. Relationships between attitudes and environmental factors that influence net longevity were measured with adherence to bed net care practices.

Results

While overall care practices are highly adherent particularly in the highlands, practices related to daily storage, washing frequency, and drying location need improvement in the lowlands. Seventy-seven percent of nets in the lowlands were washed < 3 months prior to the survey compared to 23% of nets in the highlands. More nets were dried in the sun in the lowlands (32% of nets) compared to the highlands (4% of nets). Different elements of care are influenced by various malaria attitudes and environmental factors, highlighting the complexity of factors associated with net care. For example, households that learned about net care from community events, that share a sleeping structure with animals, and that have nets used by adult males tend to adhere to washing frequency recommendations.

Conclusions

In western Kenya, many nets are cared for in accordance to recommended practices, particularly in the highlands sites. In the lowlands, demonstrating methods at community events to tie nets up during the day coupled with messaging to emphasize infrequent washing and drying nets in the shade may be an appropriate intervention. As illustrated by differences between the highlands and lowlands sites in the present study, should interventions to improve adherence to bed net care practices be necessary, they should be context-specific.

Electronic supplementary material

The online version of this article (10.1186/s12936-019-2908-6) contains supplementary material, which is available to authorized users.

Validation of Questionnaire Methods to Quantify Recreational Water Ingestion

Swimming pool water ingestion volumes are necessary for assessing infection risk from swimming. Pool water ingestion volumes can be estimated by questionnaire or measuring a chemical tracer in swimmer urine. Questionnaires are often preferred to the chemical tracer method because surveys are less time consuming, but no research exists validating questionnaires accurately quantify pool water ingestion volumes. The objective of this study was to explore if questionnaires are a reliable tool for collecting pool water ingestion volumes. A questionnaire was issued at four pool sites in Tucson, Arizona to 46 swimmers who also submitted a urine sample for analyzing cyanuric acid, a chemical tracer. Perceived ingestion volumes reported on the questionnaire were compared with pool water ingestion volumes, quantified by analyzing cyanuric acid in swimmer urine. Swimmers were asked if they swallowed (1) no water or only a few drops, (2) one to two mouthfuls, (3) three to five mouthfuls, or (4) six to eight mouthfuls. One mouthful is the equivalent of 27 mL of water. The majority (81%) of swimmers ingested <27 mL of pool water but reported ingesting >27 mL ("one mouthful") on the questionnaire. More than half (52%) of swimmers overestimated their ingestion volume. These findings suggest swimmers are over-estimating pool water ingestion because they perceive one mouthful is <27 mL. The questionnaire did not reliably collect pool water ingestion volumes and should be improved for future exposure assessment studies. Images of the ingestion volume categories should be included on the questionnaire to help swimmers visualize the response options.

Increasing women's engagement in vector control: a report from Accelerate To Equal project workshops

Workshops with academic, national and local government, and community stakeholders were held in Kenya (2017) and Indonesia (2018) to understand the role and perceptions of women in vector control and to identify strategies for accelerating involvement of women in sustained support for vector control interventions at multiple levels/sectors.

Socioeconomic and Human Behavioral Factors Associated With Aedes aegypti (Diptera: Culicidae) Immature Habitat in Tucson, AZ

Aedes aegypti (L.; Diptera: Culicidae) has been established in the southwestern United States for several decades, but relationships between humans and mosquitoes in this arid region are not well-characterized. In August 2012, the outdoor premises of 355 houses within 20 neighborhoods in Tucson, Arizona were surveyed for containers that could provide larval habitat for Ae. aegypti mosquitoes. At the same time, a knowledge, attitudes and practices (KAP) questionnaire was administered to a resident of each house surveyed for immature mosquitoes. The KAP questionnaire assessed respondents' knowledge and concerns about vector-borne illnesses as well as practices they used to avoid mosquitoes. Of the houses surveyed, 91% had at least one container present, and 64% had at least one container with standing water. On average, each house had 2.2 containers with water at the time of the survey. The overall House Index (proportion of premises surveyed with at least one container with Ae. aegypti immatures present) was 13%. Based on questionnaire responses, there was a significant positive association between the number of residents in the home and the odds of finding Ae. aegypti positive containers on the premises, while household income showed a significant negative association. The reported frequency of checking for standing water was also significantly associated with the odds of finding immatures, although the nature of this association was ambiguous. Flower pots were the principal type of container with Ae. aegypti larvae. These findings show that larval habitat is widely available even in an arid environment and city with good housing and sanitation infrastructure.

Measuring Women's Empowerment in Sub-Saharan Africa: Exploratory and Confirmatory Factor Analyses of the Demographic and Health Surveys

Background: Women's status and empowerment influence health, nutrition, and socioeconomic status of women and their children. Despite its benefits, however, research on women's empowerment in Sub-Saharan Africa (SSA) is limited in scope and geography. Empowerment is variably defined and data for comparison across regions is often limited. The objective of the current study was to identify domains of empowerment from a widely available data source, Demographic and Health Surveys, across multiple regions in SSA.

Methods: Demographic and Health Surveys from nineteen countries representing four African regions were used for the analysis. A total of 26 indicators across different dimensions (economic, socio-cultural, education, and health) were used to characterize women's empowerment. Pooled data from all countries were randomly divided into two datasets—one for exploratory factor analysis (EFA) and the other for Confirmatory Factor Analysis (CFA)—to verify the factor structure hypothesized during EFA.

Results: Four factors including attitudes toward violence, labor force participation, education, and access to healthcare were found to define women's empowerment in Central, Southern, and West Africa. However, in East Africa, only three factors were relevant: attitudes toward violence, access to healthcare ranking, and labor force participation. There was limited evidence to support household decision-making, life course, or legal status domains as components of women's empowerment.

Conclusion: This foremost study advances scholarship on women's empowerment by providing a validated measure of women's empowerment for researchers and other stakeholders in health and development.

Parental attitudes and perceptions associated with childhood vaccine exemptions in high-exemption schools

Previous work demonstrates that individuals who obtain exemptions from school immunization requirements are geographically clustered, making regional differences in vaccination coverage a significant concern. Even where exemption levels are high, there are still parents that vaccinate. School-level assessments have determined that exemptors are more likely to attend wealthier schools with fewer minorities. Few studies have assessed divergent opinions within the context of a higher-exemption community to examine subtle differences in opinion surrounding vaccinations. Therefore, the objective of this work was to assess attitudes and perceptions towards vaccinations and compare them for exemptors and non-exemptors. We administered surveys to parents in high-exemption (>10%) elementary schools in Arizona during the 2012–13 school year. A total of 404 surveys were completed by parents among schools in Maricopa (n = 7) and Yavapai (n = 2) counties. Of these, 35% (n = 141) were exemptors and 65% (n = 261) were non-exemptors. Exemptors were more likely than non-exemptors to be concerned about serious side-effects (p<0.001). They were more likely to report knowing someone who had been diagnosed with a vaccine-preventable disease (p<0.001) but less likely to report that this had been a serious illness in that person (p<0.001) and they believed it is better for a child to develop immunity through illness than vaccination (p<0.001). They were less likely to trust physicians (p<0.001) and information about vaccines (p<0.001) and were more likely to obtain their health care from a naturopath (p<0.001). In summary, exemptors in these Arizona schools do not appear to be exempting their children from vaccinations due to convenience, as has been hypothesized in other settings. Based on the divergent views within high-exemption schools and reported distrust of the medical establishment, target interventions for high-exemption schools are discussed. Additionally, given the lack of effective non-policy based interventions to-date, the negligible declines in personal belief exemption rates, and vaccine preventable disease rate increases in Arizona, especially in high-exemption areas, legislative action in Arizona may also warrant further investigation.

Effects of desiccation stress on adult female longevity in Aedes aegypti and Ae. albopictus (Diptera: Culicidae): results of a systematic review and pooled survival analysis

Background

Transmission dynamics of mosquito-borne viruses such as dengue, Zika and chikungunya are affected by the longevity of the adult female mosquito. Environmental conditions influence the survival of adult female Aedes mosquitoes, the primary vectors of these viruses. While the association of temperature with Aedes mortality has been relatively well-explored, the role of humidity is less established. The current study’s goals were to compile knowledge of the influence of humidity on adult survival in the important vector species Aedes aegypti and Ae. albopictus, and to quantify this relationship while accounting for the modifying effect of temperature.

Methods

We performed a systematic literature review to identify studies reporting experimental results informing the relationships among temperature, humidity and adult survival in Ae. aegypti and Ae. albopictus. Using a novel simulation approach to harmonize disparate survival data, we conducted pooled survival analyses via stratified and mixed effects Cox regression to estimate temperature-dependent associations between humidity and mortality risk for these species across a broad range of temperatures and vapor pressure deficits.

Results

After screening 1517 articles, 17 studies (one in semi-field and 16 in laboratory settings) met inclusion criteria and collectively reported results for 192 survival experiments. We review and synthesize relevant findings from these studies. Our stratified model estimated a strong temperature-dependent association of humidity with mortality in both species, though associations were not significant for Ae. albopictus in the mixed effects model. Lowest mortality risks were estimated around 27.5 °C and 21.5 °C for Ae. aegypti and Ae. albopictus, respectively, and mortality increased non-linearly with decreasing humidity. Aedes aegypti had a survival advantage relative to Ae. albopictus in the stratified model under most conditions, but species differences were not significant in the mixed effects model.

Conclusions

Humidity is associated with mortality risk in adult female Ae. aegypti in controlled settings. Data are limited at low humidities, temperature extremes, and for Ae. albopictus, and further studies should be conducted to reduce model uncertainty in these contexts. Desiccation is likely an important factor in Aedes population dynamics and viral transmission in arid regions. Models of Aedes-borne virus transmission may be improved by more comprehensively representing humidity effects.

Electronic supplementary material

The online version of this article (10.1186/s13071-018-2808-6) contains supplementary material, which is available to authorized users.

Barriers and Opportunities to Advancing Women in Leadership Roles in Vector Control: Perspectives from a Stakeholder Survey

Increasing the active participation of professional women in vector control (VC) activities may help promote greater gender equity in the workplace and reduce the burden of vector-borne diseases. This stakeholder survey examined the current roles and perspective of professionals employed in the VC sector in Kenya, Indonesia, India, and other countries. The largest barriers that women face in pursuing leadership roles in the VC sector include lack of awareness of career opportunities, limitations based on cultural norms, and the belief that VC is men’s work. These barriers could be addressed through improving education and recruitment campaigns, as well as supporting higher education and mentoring programs. Females were almost six times more likely to be encouraged to pursue leadership positions in their organization compared with male respondents (odds ratio = 5.9, P > 0.03, 95% confidence interval: 1.19, 29.42). These findings suggest that once women are recruited into the VC workforce, they face minimal discrimination and have increased leadership opportunities.

The potential impacts of 21st century climatic and population changes on human exposure to the virus vector mosquito Aedes aegypti

The mosquito Aedes (Ae). aegypti transmits the viruses that cause dengue and chikungunya, two globally-important vector-borne diseases. We investigate how choosing alternate emissions and/or socioeconomic pathways may modulate future human exposure to Ae. aegypti. Occurrence patterns for Ae. aegypti for 2061-2080 are mapped globally using empirically downscaled air temperature and precipitation projections from the Community Earth System Model, for the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios. Population growth is quantified using gridded global population projections consistent with two Shared Socioeconomic Pathways (SSPs), SSP3 and SSP5. Change scenarios are compared to a 1950-2000 reference period. A global land area of 56.9 M km² is climatically suitable for Ae. aegypti during the reference period, and is projected to increase by 8% (RCP4.5) to 13% (RCP8.5) by 2061-2080. The annual average number of people exposed globally to Ae. aegypti for the reference period is 3794 M, a value projected to statistically significantly increase by 298-460 M (8-12%) by 2061-2080 if only climate change is considered, and by 4805-5084 M (127-134%) for SSP3 and 2232-2483 M (59-65%) for SSP5 considering both climate and population change (lower and upper values of each range represent RCP4.5 and RCP8.5 respectively). Thus, taking the lower-emissions RCP4.5 pathway instead of RCP8.5 may mitigate future human exposure to Ae. aegypti globally, but the effect of population growth on exposure will likely be larger. Regionally, Australia, Europe and North America are projected to have the largest percentage increases in human exposure to Ae. aegypti considering only climate change.

Current strategies and successes in engaging women in vector control: a systematic review

INTRODUCTION

Vector-borne diseases (VBDs) cause significant mortality and morbidity in low-income and middle-income countries and present a risk to high-income countries. Vector control programmes may confront social and cultural norms that impede their execution. Anecdotal evidence suggests that incorporating women in the design, delivery and adoption of health interventions increases acceptance and compliance. A better understanding of programmes that have attempted to increase women's involvement in vector control could help shape best practices. The objective of this systematic review was to assess and critically summarise evidence regarding the effectiveness of women participating in vector control.

METHODS

Seven databases were searched from inception to 21 December 2015. Two investigators independently reviewed all titles and abstracts for relevant articles. Grey literature was searched by assessing websites that focus on international development and vector control.

RESULTS

In total, 23 articles representing 17 unique studies were included in this review. Studies discussed the involvement of women in the control of vectors for malaria (n=10), dengue (n=8), human African trypanosomiasis (n=3), schistosomiasis (n=1) and a combination (malaria and schistosomiasis, n=1). Seven programmes were found in the grey literature or through personal communications. Available literature indicates that women can be successfully engaged in vector control programmes and, when given the opportunity, they can create and sustain businesses that aim to decrease the burden of VBDs in their communities.

CONCLUSION

This systematic review demonstrated that women can be successfully engaged in vector control programmes at the community level. However, rigorous comparative effectiveness studies need to be conducted.

Lessons From the Implementation of Mo-Buzz, a Mobile Pandemic Surveillance System for Dengue

BACKGROUND

Approximately 128 countries and 3.9 billion people are at risk of dengue infection. Incidence of dengue has increased over the past decades, becoming a growing public health concern for countries with populations that are increasingly susceptible to this vector-borne disease, such as Sri Lanka. Almost 55,150 dengue cases were reported in Sri Lanka in 2016, with more than 30.40% of cases (n=16,767) originating from Colombo, which struggles with an outdated manual paper-based dengue outbreak management system. Community education and outreach about dengue are also executed using paper-based media channels such as pamphlets and brochures. Yet, Sri Lanka is one of the countries with the most affordable rates of mobile services in the world, with penetration rates higher than most developing countries.

OBJECTIVES

To combat the issues of an exhausted dengue management system and to make use of new technology, in 2015, a mobile participatory system for dengue surveillance called Mo-Buzz was developed and launched in Colombo, Sri Lanka. This paper describes the system's components and uptake, along with other similar disease surveillance systems.

METHODS

We developed Mo-Buzz and tested its feasibility for dengue. Two versions of the app were developed. The first was for use by public health inspectors (PHIs) to digitize form filling and recording of site visit information, and track dengue outbreaks on a real-time dengue hotspot map using the global positioning system technology. The system also provides updated dengue infographics and educational materials for the PHIs to educate the general public. The second version of Mo-Buzz was created for use by the general public. This system uses dynamic mapping to help educate and inform the general public about potential outbreak regions and allow them to report dengue symptoms and post pictures of potential dengue mosquito-breeding sites, which are automatically sent to the health authorities. Targeted alerts can be sent to users depending on their geographical location.

RESULTS

We assessed the usage and the usability of the app and its impact on overall dengue transmission in Colombo. Initial uptake of Mo-Buzz for PHIs was low; however, after more training and incentivizing of usage, the uptake of the app in PHIs increased from less than 10% (n=3) to 76% (n=38). The general public user evaluation feedback was fruitful in providing improvements to the app, and at present, a number of solutions are being reviewed as viable options to boost user uptake.

CONCLUSIONS

From our Mo-Buzz study, we have learned that initial acceptance of such systems can be slow but eventually positive. Mobile and social media interventions, such as Mo-Buzz, are poised to play a greater role in shaping risk perceptions and managing seasonal and sporadic outbreaks of infectious diseases in Asia and around the world.

Outdoor spatial spraying against dengue: A false sense of security among inhabitants of Hermosillo, Mexico

Background

Government-administered adulticiding is frequently conducted in response to dengue transmission worldwide. Anecdotal evidence suggests that spraying may create a “false sense of security” for residents. Our objective was to determine if there was an association between residents’ reporting outdoor spatial insecticide spraying as way to prevent dengue transmission and both their reported frequency of dengue prevention practices and household entomological indices in Hermosillo, Mexico.

Methodology/Principal findings

A non-probabilistic survey of 400 households was conducted in August 2014. An oral questionnaire was administered to an adult resident and the outer premises of the home were inspected for water-holding containers and presence of Ae. aegypti larvae and pupae. Self-reported frequency of prevention practices were assessed among residents who reported outdoor spatial spraying as a strategy to prevent dengue (n = 93) and those who did not (n = 307). Mixed effects negative binomial regression was used to assess associations between resident’s reporting spraying as a means to prevent dengue and container indices. Mixed effects logistic regression was used to determine associations with presence/absence of larvae and pupae. Those reporting spatial spraying disposed of trash less frequently and spent less time indoors to avoid mosquitoes. They also used insecticides and larvicides more often and covered their water containers more frequently. Their backyards had more containers positive for Ae. aegypti (RR = 1.92) and there was a higher probability of finding one or more Ae. aegypti pupae (OR = 2.20). Survey respondents that reported spatial spraying prevented dengue were more likely to be older and were exposed to fewer media sources regarding prevention.

Conclusions/Significance

The results suggest that the perception that outdoor spatial spraying prevents dengue is associated with lower adoption of prevention practices and higher entomological risk. This provides some support to the hypothesis that spraying may lead to a “false sense of security”. Further investigations to clarify this relationship should be conducted. Government campaigns should emphasize the difficulty in controlling Ae. aegypti mosquitoes and the need for both government and community action to minimize risk of dengue transmission.

Outdoor spatial spraying is commonly practiced by local governments as a prevention strategy for dengue and other Aedes-borne viruses. However, it has been publically criticized for its potential to reduce community-level actions such as clearance of mosquito habitat due to a resulting “false sense of security”. This study uses a paired social and entomological survey to analyze the association between residents’ perception that outdoor spraying prevents dengue and household level dengue fever prevention practices and entomological indicators in a city in northern Mexico. Our results suggest that those who view dengue is prevented by outdoor spatial spraying had 1) lower frequencies of elimination of potential mosquito breeding sites and higher frequencies of exposure to the vector, 2) higher entomological risk, and 3) a different socio-demographic profile than those who did not report it as effective. Our findings support the possibility that outdoor space spraying may lead to a “false sense of security” which reduces household engagement in prevention activities.

Prevalence of Caesarean sections in Enugu, southeast Nigeria: Analysis of data from the Healthy Beginning Initiative

Background

In order to meet the Sustainable Development Goal to decrease maternal mortality, increased access to obstetric interventions such as Caesarean sections (CS) is of critical importance. As a result of women’s limited access to routine and emergency obstetric services in Nigeria, the country is a major contributor to the global burden of maternal mortality. In this analysis, we aim to establish rates of CS and determine socioeconomic or medical risk factors associated with having a CS in Enugu, southeast Nigeria.

Methods

Data for this study originated from the Healthy Beginning Initiative study. Participant characteristics were obtained from 2300 women at baseline via a semi-structured questionnaire. Only women between the ages of 17–45 who had singleton deliveries were retained for this analysis. Post-delivery questionnaires were used to ascertain mode-of-delivery. Crude and adjusted logistic regressions with Caesarean as the main outcome are presented.

Results

In this sample, 7.22% women had a CS. Compared to women who lived in an urban setting, those who lived in a rural setting had a significant reduction in the odds of having a CS (aOR: 0.58; 0.38–0.89). Significantly higher odds of having a CS were seen among those with high peripheral malaria parasitemia compared to those with low parasitemia (aOR: 1.54; 1.04–2.28).

Conclusion

This study revealed that contrary to the increasing trend in use of CS in low-income countries, women in this region of Nigeria had limited access to this intervention. Increasing age and socioeconomic proxies for income and access to care (e.g., having a tertiary-level education, full-time employment, and urban residence) were shown to be key determinants of access to CS. Further research is needed to ascertain the obstetric conditions under which women in this region receive CS, and to further elucidate the role of socioeconomic factors in accessing CS.

Spatio-temporal and neighborhood characteristics of two dengue outbreaks in two arid cities of Mexico

Little is currently known about the spatial-temporal dynamics of dengue epidemics in arid areas. This study assesses dengue outbreaks that occurred in two arid cities of Mexico, Hermosillo and Navojoa, located in northern state of Sonora. Laboratory confirmed dengue cases from Hermosillo (N=2730) and Navojoa (N=493) were geocoded by residence and assigned neighborhood-level characteristics from the 2010 Mexican census. Kernel density and Space-time cluster analysis was performed to detect high density areas and space-time clusters of dengue. Ordinary Least Square regression was used to assess the changing socioeconomic characteristics of cases over the course of the outbreaks. Both cities exhibited contiguous patterns of space-time clustering. Initial areas of dissemination were characterized in both cities by high population density, high percentage of occupied houses, and lack of healthcare. Future research and control efforts in these regions should consider these space-time and socioeconomic patterns.

Body Mass Index, Waist Circumference, and Mortality in a Large Multiethnic Postmenopausal Cohort-Results from the Women's Health Initiative

OBJECTIVES

To determine whether the relationship between anthropometric measurements of obesity and mortality varies according to age, race, and ethnicity in older women.

DESIGN

Prospective cohort study of multiethnic postmenopausal women.

SETTING

Women's Health Initiative (WHI) observational study and clinical trials in 40 clinics.

PARTICIPANTS

Postmenopausal women aged 50-79 participating in WHI (N = 161,808).

MEASUREMENTS

Baseline height, weight, and waist circumference (WC) were measured, and body mass index (BMI) was calculated based on height and weight. Demographic, health, and lifestyle data from a baseline questionnaire were used as covariates. The outcome was adjudicated death (n = 18,320) during a mean follow-up of 11.4 ± 3.2 years.

RESULTS

Hazard ratios (HRs) and 95% confidence intervals (95% CIs) indicated that ethnicity and age modified (P < .01) the relationship between obesity and mortality. Underweight was associated with higher mortality, but overweight or slight obesity was not a risk factor for mortality in most ethnic groups except for Hispanic women in the obesity I category (HR = 1.42, 95% CI = 1.04-1.95). BMI was not or was only weakly associated with mortality in individuals aged 70-79 (HR = 0.90, 95% CI = 0.85-0.95 for overweight; HR = 0.98, 95 CI = 0.92-1.06 for obese I; HR = 1.11, 95% CI = 1.00-1.23 for obese II; HR = 1.08, 95% CI = 0.92-1.26 for obese III). In contrast, higher central obesity measured using WC was consistently associated with higher mortality in all groups.

CONCLUSION

Underweight is a significant risk factor for mortality in older women, and healthy BMI ranges may need to be specific for age, race, and ethnicity. The findings support a consistent relationship between central obesity and mortality.

Reported bed net ownership and use in social contacts is associated with uptake of bed nets for malaria prevention in pregnant women in Ghana

Background

Despite progress made in the last decades, malaria persists as a pressing health issue in sub-Saharan Africa. Pregnant women are particularly vulnerable to infection and serious health outcomes for themselves and their unborn child. Risk can be mitigated through appropriate use of control measures such as insecticide-treated bed nets. Although social networks can influence uptake of preventive strategies, the role of social influence on bed net ownership has not been explored. During an evaluation of a bed net distribution programme, the influence of non-health care advisors on ownership and use of bed nets by pregnant women in Kumasi, Ghana was examined.

Methods

Data were collected through in-person interviews with 300 pregnant women seeking antenatal care in an urban hospital in Kumasi, Ghana. Participants were asked about their bed net ownership, bed net use, and information about three personal contacts that they go to for pregnancy advice. Information about these advisors was combined into an influence score. Logistic regression models were used to determine the association between the score and bed net ownership. Those who owned a bed net were further assessed to determine if interpersonal influence was associated with self-reported sleeping under the bed net the previous night.

Results

Of the 294 women in the analysis, 229 (78%) reported owning bed nets. Of these bed net owners, 139 (61%) reported using a bed net the previous night. A dose response relationship was observed between the interpersonal influence score and bed net ownership and use. Compared to the lowest influence score, those with the highest influence score (>1 SD above the mean) were marginally more likely to own a bed net [OR = 2.37, 95% CI (0.87, 6.39)] and much more likely to use their bed net [5.38, 95% CI (1.89, 15.25)] after adjusting for other factors.

Conclusions

Interpersonal influence appears to have modest impact on ownership and use of bed nets by pregnant women in an urban area of Ghana. Further investigations would need to be conducted to determine if the relationship is causal or if individuals who associate are simply more likely to have similar practices.

Electronic supplementary material

The online version of this article (doi:10.1186/s12936-016-1660-4) contains supplementary material, which is available to authorized users.

Aedes aegypti (Diptera: Culicidae) Longevity and Differential Emergence of Dengue Fever in Two Cities in Sonora, Mexico

Dengue virus, primarily transmitted by the Aedes aegypti (L.) mosquito, has rapidly expanded in geographic extent over the past several decades. In some areas, however, dengue fever has not emerged despite established Ae. aegypti populations. The reasons for this are unclear and have sometimes been attributed to socio-economic differences. In 2013 we compared Ae. aegypti adult density and population age structure between two cities in Sonora, Mexico: Hermosillo, which has regular seasonal dengue virus transmission, and Nogales, which has minimal transmission. Larval and pupal abundance was greater in Nogales, and adult density was only higher in Hermosillo during September. Population age structure, however, was consistently older in Hermosillo. This difference in longevity may have been one factor that limited dengue virus transmission in Nogales in 2013, as a smaller proportion of Ae. aegypti females survived past the extrinsic incubation period.

Mosquito Avoidance Practices and Knowledge of Arboviral Diseases in Cities with Differing Recent History of Disease

As the range of dengue virus (DENV) transmission expands, an understanding of community uptake of prevention and control strategies is needed both in geographic areas where the virus has recently been circulating and in areas with the potential for DENV introduction. Personal protective behaviors such as the use of mosquito repellent to limit human-vector contact and the reduction of vector density through elimination of oviposition sites are the primary control methods for Aedes aegypti, the main vector of DENV. Here, we examined personal mosquito control measures taken by individuals in Key West, FL, in 2012, which had experienced a recent outbreak of DENV, and Tucson, AZ, which has a high potential for introduction but has not yet experienced autochthonous transmission. In both cities, there was a positive association between the numbers of mosquitoes noticed outdoors and the overall number of avoidance behaviors, use of repellent, and removal of standing water. Increased awareness and perceived risk of DENV were associated with increases in one of the most effective household prevention behaviors, removal of standing water, but only in Key West.

Comparing ownership and use of bed nets at two sites with differential malaria transmission in western Kenya

Background

Challenges persist in ensuring access to and optimal use of long-lasting, insecticidal bed nets (LLINs). Factors associated with ownership and use may differ depending on the history of malaria and prevention control efforts in a specific region. Understanding how the cultural and social-environmental context of bed net use may differ between high- and low-risk regions is important when identifying solutions to improve uptake and appropriate use.

Methods

Community forums and a household, cross-sectional survey were used to collect information on factors related to bed net ownership and use in western Kenya. Sites with disparate levels of transmission were selected, including an endemic lowland area, Miwani, and a highland epidemic-prone area, Kapkangani. Analysis of ownership was stratified by site. A combined site analysis was conducted to examine factors associated with use of all available bed nets. Logistic regression modelling was used to determine factors associated with ownership and use of owned bed nets.

Results

Access to bed nets as the leading barrier to their use was identified in community forums and cross-sectional surveys. While disuse of available bed nets was discussed in the forums, it was a relatively rare occurrence in both sites. Factors associated with ownership varied by site. Education, perceived risk of malaria and knowledge of individuals who had died of malaria were associated with higher bed net ownership in the highlands, while in the lowlands individuals reporting it was easy to get a bed net were more likely to own one. A combined site analysis indicated that not using an available bed net was associated with the attitudes that taking malaria drugs is easier than using a bed net and that use of a bed net will not prevent malaria. In addition, individuals with an unused bed net in the household were more likely to indicate that bed nets are difficult to use, that purchased bed nets are better than freely distributed ones, and that bed nets should only be used during the rainy season.

Conclusion

Variations in factors associated with ownership should be acknowledged when constructing messaging and distribution campaigns. Despite reports of bed nets being used for other purposes, those in the home were rarely unused in these communities. Disuse seemed to be related to beliefs that can be addressed through education programmes. As mass distributions continue to take place, additional research is needed to determine if factors associated with LLIN ownership and use change with increasing availability of LLIN.