Epidemiology of and programmatic response to tuberculosis in Solomon Islands: analysis of surveillance data, 2016-2022.

Objective: To identify progress and challenges in the national response to tuberculosis (TB) in Solomon Islands through an epidemiological overview of TB in the country. Methods: A descriptive analysis was conducted using the national TB surveillance data for 2016-2022. Case notifications, testing data, treatment outcomes and screening activities were analysed. Results: The number of case notifications was 343 in 2022, with an average annual reduction of the case notification rate between 2016 and 2022 of 4.7%. The highest case notification rate was reported by Honiara City Council (126/100 000 population) in 2022. The number of people with presumptive TB tested by Xpert® rapidly increased from zero in 2016 to 870 in 2022. Treatment success rate remained consistently high between 2016 and 2022, ranging from 92% to 96%. Screening for HIV and diabetes mellitus (DM) among TB patients in 2022 was 14% and 38%, respectively. Most patients (97%) were hospitalized during the intensive phase of treatment in 2022; in contrast, during the continuation phase, the proportion of patients treated at the community level increased from 1% in 2016 to 63% in 2022. Despite an increase in household contact investigations, from 381 in 2016 to 707 in 2021, the uptake of TB preventive treatment (TPT) was minimal (7% among eligible child contacts). Discussion: This epidemiological analysis in Solomon Islands reveals both notable achievements and challenges in the country's TB programme. One major achievement is a potential actual reduction in TB incidence. Challenges identified were potential underdetection of cases in rural areas, suboptimal community-based care, and insufficient contact tracing and uptake of TPT. It is crucial to address these challenges (e.g. by optimizing resources) to advance the national TB response.

Experience and impact of gender-based violence in Honiara, Solomon Islands: a cross-sectional study recording violence over a 12-month period.

OBJECTIVE: This study aims to collect data on the experience and impact of gender-based violence experienced by women attending health clinics in Honiara, Solomon Islands. METHOD: Any woman over the age of 18 who attended a local health clinic in Honiara, Solomon Islands during the time of recruitment (ten consecutive weekdays in May 2015) was eligible to participate in an interviewer administered, in-person survey, gathering data on gender-based violence over the past 12 months. RESULTS: A total of 100 women were recruited into this study. Of these women, 47% of women reported experiencing physical or sexual violence in the past 12 months. The most common perpetrators were the woman's husband or boyfriend. There are low rates of reporting, particularly through formal avenues such as to police or village leaders. Alcohol was involved in more than half the cases of reported violence. CONCLUSION: Women in this study report high rates of gender-based violence. To our knowledge, this is the only study examining women's personal experience of gender-based violence in the Solomon Islands, with self-reported data on the frequency and nature of the violence, and the impact on women, including physical and mental, utilisation of healthcare services, police and legal involvement. Efforts to reduce gender-based violence should aim to reduce intimate partner violence, increase reporting and address wider social attitudes towards gender equality.

Effects of temperature, rainfall, and El Niño Southern Oscillations on dengue-like-illness incidence in Solomon Islands.

BACKGROUND: This study investigated associations between climate variables (average temperature and cumulative rainfall), and El Niño Southern Oscillation (ENSO) and dengue-like-illness (DLI) incidence in two provinces (Western and Guadalcanal Provinces) in Solomon Islands (SI). METHODS: Weekly DLI and meteorological data were obtained from the Ministry of Health and Medical Services SI and the Ministry of Environment, Climate Change, Disaster Management and Meteorology from 2015 to 2018, respectively. We used negative binomial generalized estimating equations to assess the effects of climate variables up to a lag of 2 months and ENSO on DLI incidence in SI. RESULTS: We captured an upsurge in DLI trend between August 2016 and April 2017. We found the effects of average temperature on DLI in Guadalcanal Province at lag of one month (IRR: 2.186, 95% CI: 1.094-4.368). Rainfall had minor but consistent effect in all provinces. La Niña associated with increased DLI risks in Guadalcanal Province (IRR: 4.537, 95% CI: 2.042-10.083), whereas El Niño associated with risk reduction ranging from 72.8% to 76.7% in both provinces. CONCLUSIONS: Owing to the effects of climate variability and ENSO on DLI, defining suitable and sustainable measures to control dengue transmission and enhancing community resilience against climate change in low- and middle-developed countries are important.

Prevalence and Factors Associated With Low Birth Weight in the Solomon Islands: Evidence From the 2015 Solomon Islands Demographic and Health Survey data.

Low birth weight (LBW) has contributed to more than 80% of under-5 deaths worldwide, most occurring in low- and middle-income countries. We used the 2015 Solomon Islands Demographic and Health Survey data to identify the prevalence and risks associated with LBW in the Solomon Islands. Low birth weight prevalence estimated was 10%. After adjustment for potential confounders, we found the risk of LBW for women with a history of marijuana and kava use was 2.6 times, adjusted relative risk (aRR) 2.64 and 2.5 times (aRR: 2.50) than among unexposed women, respectively. Polygamous relationship, no antenatal care, decision-making by another person were 84% (aRR: 1.84), 73% (aRR: 1.73), and 73% (aRR: 1.73) than among unexposed women, respectively. We also found that 10% and 4% of LBW cases in the Solomon Islands were attributable to a household of more than five members and tobacco and cigarette use history respectively. We concluded that LBW in the Solomon Islands relied more on behavioral risk factors, including substance use as well as health and social risk factors. We recommended further study on kava use and its impact on pregnancy and LBW.

Incidence and causes of stillbirth in the only tertiary referral hospital in the Solomon Islands: a hospital-based retrospective cohort study.

OBJECTIVES: Stillbirth is a major global health issue, which disproportionately affects families living in low-income and middle-income countries. The Solomon Islands is a Pacific nation with poor perinatal outcomes, however research investigating stillbirth is lacking. Thus, we aimed to investigate the incidence and cause of stillbirth occurring at the National Referral Hospital, Solomon Islands. DESIGN: We conducted a retrospective cohort study from January 2017 to December 2018. SETTING: At the only tertiary referral hospital in the Solomon Islands, on the main island of Guadalcanal. PARTICIPANTS: All births occurring in the hospital during the study period. OUTCOME MEASURES: Number of, causes and risk factors for stillbirths (fetal deaths before birth at ≥20 estimated gestational weeks, or ≥500 g in birth weight). RESULTS: Over 2 years 341 stillbirths and 11 056 total births were recorded, giving an institutional incidence of 31 stillbirths per 1000 births. Of the cases with a recorded cause of death, 72% were deemed preventable. Most stillbirths occurred antenatally and 62% at preterm gestations (<37 weeks). 59% had a birth weight below 2500 g and preventable maternal conditions were present in 42% of the cases. 46% of the cases were caused by an acute intrapartum event, and among these 92% did not receive intrapartum monitoring. CONCLUSIONS: Stillbirth affects 31 in every 1000 births at the National Referral Hospital in the Solomon Islands and many cases are preventable. Our findings highlight the urgent need for increased focus on perinatal deaths in the Solomon Islands with universal classification and targeted training, improved quality of obstetrical care and community awareness.

Using quantitative PCR to identify opportunities to strengthen soil-transmitted helminth control in Solomon Islands: A cross-sectional epidemiological survey.

BACKGROUND: The Kato-Katz microscopy technique is the global standard for assessment of soil-transmitted helminth (STH) burden. However, major limitations include its poor sensitivity, requirement for rapid sample processing, and inability to differentiate hookworm species nor detect Strongyloides spp. infections. We assessed the prevalence and intensity of STH species in Solomon Islands by conducting a province-wide survey using quantitative PCR (qPCR) for diagnosis, which can provide much better characterisation of STH burden than microscopy. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a cross-sectional survey in 18 villages in Western Province to detect infections with six STH species and quantify intensity with three. We used linear mixed model regression to identify potential water, sanitation, and hygiene (WASH) and environmental risk factors for infection. We collected stool specimens from 830 village residents. Overall STH prevalence was 63.3% (range 27.5 to 91.5% across villages), led by Necator americanus (54.5% [range 17.5-89.4%]), followed by Ancylostoma ceylanicum (15.5% [range 2.8-45.8%]), Trichuris trichiura (9.1% [range 0-79.2%]), and Strongyloides spp. (3.2% [range 0-29.2%]). Most infections were of light intensity for N. americanus (85.7%) and T. trichiura (90.7%). Owning a household latrine was associated with a lower risk of N. americanus infection (AOR 0.41, 95% CI 0.24-0.68) while greater precipitation was linked to more common T. trichiura infection (AOR 1.14, 95% CI 1.04-1.25). CONCLUSION/SIGNIFICANCE: In this first large-scale population survey of STH in the Pacific using qPCR, we found evidence that ivermectin should be incorporated into STH control programmes because of the presence of T. trichiura and Strongyloides spp., both of which are poorly responsive to albendazole. Furthermore, One Health strategies are needed for improved A. ceylanicum and Strongyloides spp. control, WASH access and use should be improved to complement deworming programmes, and control efforts should ideally be expanded to entire communities. TRIAL REGISTRATION: ClinicalTrials.gov Australian and New Zealand Clinical Trials Registry ACTRN12618001086257.

Seroprevalence of dengue, Zika, chikungunya and Ross River viruses across the Solomon Islands.

Across the Pacific, and including in the Solomon Islands, outbreaks of arboviruses such as dengue, chikungunya, and Zika are increasing in frequency, scale and impact. Outbreaks of mosquito-borne disease have the potential to overwhelm the health systems of small island nations. This study mapped the seroprevalence of dengue, Zika, chikungunya and Ross River viruses in 5 study sites in the Solomon Islands. Serum samples from 1,021 participants were analysed by ELISA. Overall, 56% of participants were flavivirus-seropositive for dengue (28%), Zika (1%) or both flaviviruses (27%); and 53% of participants were alphavirus-seropositive for chikungunya (3%), Ross River virus (31%) or both alphaviruses (18%). Seroprevalence for both flaviviruses and alphaviruses varied by village and age of the participant. The most prevalent arboviruses in the Solomon Islands were dengue and Ross River virus. The high seroprevalence of dengue suggests that herd immunity may be a driver of dengue outbreak dynamics in the Solomon Islands. Despite being undetected prior to this survey, serology results suggest that Ross River virus transmission is endemic. There is a real need to increase the diagnostic capacities for each of the arboviruses to support effective case management and to provide timely information to inform vector control efforts and other outbreak mitigation interventions.

Estimation of scabies prevalence using simplified criteria and mapping procedures in three Pacific and southeast Asian countries.

BACKGROUND: Scabies causes considerable morbidity in disadvantaged populations. The International Alliance for the Control of Scabies (IACS) published consensus criteria in 2020 to standardize scabies diagnosis. However, these criteria are complex, and a WHO informal consultation proposed simplified criteria for mapping, to identify regions of high prevalence as targets for mass drug administration. We aimed to investigate the accuracy of simplified criteria in determining scabies prevalence, compared to the 2020 IACS criteria. METHODS: We obtained data relating to demographics, relevant history and skin lesions from all-age prevalence surveys from Fiji (n = 3365) and Solomon Islands (n = 5239), as well as school-aged children in Timor-Leste (n = 1043). We calculated prevalence using the 2020 IACS criteria and simplified criteria and compared these disease estimates. RESULTS: There was no significant difference in the pooled prevalence using the two methods (2020 IACS criteria: 16.6%; simplified criteria: 15.6%; difference = 0.9, [95% CI -0.1, 2.0]). In Timor-Leste, the prevalence using simplified criteria was lower (26.5% vs 33.8%). Simplified criteria had a sensitivity of 82.3% (95% CI 80.2, 84.2) and specificity of 97.6% (95% CI 97.2, 97.9) compared to the 2020 IACS criteria. CONCLUSIONS: The scabies prevalence estimation using simplified criteria was similar to using the 2020 IACS criteria in high prevalence, tropical countries. The prevalence estimation was lower in the school-based survey in Timor-Leste. Mapping using simplified criteria may be a feasible and effective public health tool to identify priority regions for scabies control. Further work assessing use of simplified criteria for mapping in a field setting should be conducted.

Health and well-being in small island communities: a cross-sectional study in the Solomon Islands.

OBJECTIVES: This study explored the health problems of inhabitants of small South Pacific Islands under the influence of climate change, focusing on three communities in the Solomon Islands. DESIGN: Cross-sectional study of the Solomon Islands' populations. SETTING: A field survey was conducted in Taro Island, a small, urbanised island with a whole-community relocation plan; Manuopo community of Reef Islands, a small remote island on an atoll environment and Sasamungga, an intermediately urbanised community on a larger island. The Sasamungga community was used for comparison. PARTICIPANTS: Each community's participants were recruited through local health authorities, and 113, 155 and 116 adults (aged 18+ years) from Taro, Manuopo and Sasamungga, respectively, participated voluntarily. METHODS: Each participant's body height, weight and body mass index were measured. A drop of blood was sampled for malaria testing; glycated haemoglobin and C reactive protein levels, measured from another drop of blood, were markers for diabetes and inflammation, respectively. The Primary Care Screening Questionnaire for Depression measured depressive mental states. PRIMARY AND SECONDARY OUTCOME MEASURES: Regarding health status, the dependent variables-communicable diseases, non-communicable diseases and mental state-and independent variables-differences in communities and socioeconomic status-were measured through health check-ups and interviews of individual participants. RESULTS: Taro Island inhabitants had a higher risk of obesity (OR 1.13, 95% CI 1.02 to 1.27, p=0.0189), and Manuopo inhabitants had a higher risk of depression (1.25, 95% CI 1.08 to 1.44, p=0.0026) than Sasamungga inhabitants. Manuopo inhabitants recognised more serious problems of food security, livelihood, place to live and other aspects of daily living than other communities' inhabitants. CONCLUSIONS: The three small island communities' observation identified different health problems: the urbanised community and remote community had a high risk of non-communicable diseases and mental disorders, respectively. These health problems should be monitored continuously during future climate-related changes.

Perspectives of Nurses About Factors Affecting Quality of Care at the Solomon Islands National Referral Hospital During the 2016-2017 Dengue Outbreak: A Qualitative Study.

During the 2016-2017 Solomon Islands dengue outbreak, the National Referral Hospital (NRH) in Honiara was the epicenter for the national response. High-quality nursing care is critical for successful management and this study investigated the factors affecting the quality of nursing care for patients admitted to NRH with dengue. Data were collected using two methods: (a) Focus group discussions with nurses who cared for dengue patients and (b) a self-administered questionnaire completed by a senior manager. Analysis of qualitative data using a thematic technique found two key factors affected care: (a) training on protocols and guidelines for clinical management and (b) planning and preparedness of NRH. Quality of care was influenced by lack of basic equipment, transport provided for nursing staff to attend shifts, and confusion between allowances for regular salaried staff and extra staff assisting with the outbreak. Specific attention is needed in future outbreaks to ensure staff understand protocols, follow guidelines, and that adequate equipment is provided.

Getting to zero: micro-foci of malaria in the Solomon Islands requires stratified control.

BACKGROUND: The Solomon Islands has made significant progress in the control of malaria through vector control, access and use of improved diagnostics and therapeutic drugs. As transmission is reduced there is a need to understand variations in transmission risk at the provincial and village levels to stratify control methods. METHODS: A cross-sectional survey of malaria in humans was conducted in the Solomon Islands during April 2018. Nineteen villages across 4 provinces were included. The presence of Plasmodium species parasites in blood samples was detected using PCR. RESULTS: Blood samples were analysed from 1,914 participants. The prevalence of DNA of Plasmodium falciparum was 1.2 % (n = 23) and for Plasmodium vivax was 1.5 % (n = 28). 22 % (n = 5/23) of P. falciparum DNA positive participants were febrile and 17 % of P. vivax DNA positive participants (n = 5/28). The prevalence of both P. falciparum and P. vivax was extremely spatially heterogeneous. For P. falciparum, in particular, only 2 small foci of transmission were identified among 19 villages. Plasmodium falciparum infections were uniformly distributed across age groups. Insecticide-treated bed net use the night prior to the survey was reported by 63 % of participants and significantly differed by province. CONCLUSIONS: Malaria transmission across the Solomon Islands has become increasingly fragmented, affecting fewer villages and provinces. The majority of infections were afebrile suggesting the need for strong active case detection with radical cure with primaquine for P. vivax. Village-level stratification of targeted interventions based on passive and active case detection data could support the progress towards a more cost-effective and successful elimination programme.

Citizen science as a tool for arboviral vector surveillance in a resourced-constrained setting: results of a pilot study in Honiara, Solomon Islands, 2019.

BACKGROUND: Recent arboviral disease outbreaks highlight the value a better understanding of the spread of disease-carrying mosquitoes across spatial-temporal scales can provide. Traditional surveillance tools are limited by jurisdictional boundaries, workforce constraints, logistics, and cost; factors that in low- and middle-income countries often conspire to undermine public health protection efforts. To overcome these, we undertake a pilot study designed to explore if citizen science provides a feasible strategy for arboviral vector surveillance in small developing Pacific island contexts. METHODS: We recruited, trained, and equipped community volunteers to trap and type mosquitos within their household settings, and to report count data to a central authority by short-message-service. Mosquito catches were independently assessed to measure participants' mosquito identification accuracy. Other data were collected to measure the frequency and stability of reporting, and volunteers' experiences. RESULTS: Participants collected data for 78.3% of the study period, and agreement between the volunteer citizen scientists' and the reviewing entomologist's mosquito identification was 94%. Opportunity to contribute to a project of social benefit, the chance to learn new skills, and the frequency of engagement with project staff were prime motivators for participation. Unstable electricity supply (required to run the trap's fan), insufficient personal finances (to buy electricity and phone credit), and inconvenience were identified as barriers to sustained participation. CONCLUSIONS: While there are challenges to address, our findings suggest that citizen science offers an opportunity to overcome the human resource constraints that conspire to limit health authorities' capacity to monitor arboviral vectors across populations. We note that the success of citizen science-based surveillance is dependent on the appropriate selection of equipment and participants, and the quality of engagement and support provided.

Defining the need for public health control of scabies in Solomon Islands.

Pacific Island countries have a high burden of scabies and impetigo. Understanding of the epidemiology of these diseases is needed to target public health interventions such as mass drug administration (MDA). The aim of this study is to determine the prevalence of scabies and impetigo in Solomon Islands as well as the relationship between them and their distribution. We conducted a prevalence study in 20 villages in Western Province in Solomon Islands. All residents of the village were eligible to participate. Nurses conducted clinical assessments including history features and skin examination. Diagnosis of scabies was made using the 2020 International Alliance for the Control of Scabies diagnostic criteria. Assessments were completed on 5239 participants across 20 villages. Overall scabies prevalence was 15.0% (95%CI 11.8-19.1). There was considerable variation by village with a range of 3.3% to 42.6%. There was a higher prevalence of scabies in males (16.7%) than females (13.5%, adjusted relative risk 1.2, 95%CI 1.1-1.4). Children aged under two years had the highest prevalence (27%). Overall impetigo prevalence was 5.6% (95%CI 4.2-7.3), ranging from 1.4% to 19% by village. The population attributable risk of impetigo associated with scabies was 16.1% (95% CI 9.8-22.4). The prevalence of scabies in our study is comparable to previous studies in Solomon Islands, highlighting a persistent high burden of disease in the country, and the need for public health strategies for disease control.

A school-based soil-transmitted helminths survey in the Guadalcanal Province, the Solomon Islands.

Infections by soil-transmitted helminths are a major public health problem worldwide, especially among schoolchildren in low-income countries. Little information is described about their prevalence in the Solomon Islands. From 2017 to 2018, a school-based soil-transmitted helminths survey in the Guadalcanal Province was conducted. A total of 454 schoolchildren were selected; the Merthiolate-iodine-formaldehyde concentration and stain was used. The prevalence was 17% of one or more parasites, including hookworm (8.8%), Strongyloides stercoralis (5.7%), Ascaris lumbricoides (4.2%) and Trichuris trichiura (3.5%). STH infection was significantly correlated with parents' occupations, hand washing, shoe wearing as well as gastrointestinal symptoms. To prevent STH transmission for schoolchildren in the Solomon Islands completely, combined preventive strategies seem necessary.

Conjunctival Scarring, Corneal Pannus, and Herbert's Pits in Adolescent Children in Trachoma-endemic Populations of the Solomon Islands and Vanuatu.

BACKGROUND: In the Solomon Islands and Vanuatu, the sign trachomatous inflammation-follicular (TF) is common, but ocular infection with Chlamydia trachomatis is not. It is therefore debatable whether azithromycin mass drug administration (MDA), the recommended antibiotic treatment strategy for trachoma's elimination as a public health problem, is necessary in this setting. We set out to estimate what proportion of adolescents were at risk of progression of trachomatous scarring. METHODS: A cross-sectional survey was undertaken of all children aged 10-14 years resident in communities identified as high-TF clusters during previous population-based mapping. Graders examined children for clinical evidence of trachomatous scarring, pannus, and Herbert's pits (HPs) or limbal follicles in both eyes. A dried blood spot was collected from each child and tested for antibodies to C. trachomatis. RESULTS: A total of 492 children in 24 villages of the Solomon Islands and Vanuatu were examined. In total, 35/492 (7%) of children had limbal signs (pannus and/or HPs) plus any conjunctival scarring. And 9/492 (2%) had limbal signs and moderate or severe conjunctival scarring; 22% of children were anti-Pgp3 seropositive. CONCLUSIONS: Few adolescents here are at risk of future complications from trachoma, supporting the conclusion that further antibiotic MDA is not currently required for trachoma elimination purposes in these settings.

Protocol for a cluster-randomised non-inferiority trial of one versus two doses of ivermectin for the control of scabies using a mass drug administration strategy (the RISE study).

INTRODUCTION: Scabies is a significant contributor to global morbidity, affecting approximately 200 million people at any time. Scabies is endemic in many resource-limited tropical settings. Bacterial skin infection (impetigo) frequently complicates scabies infestation in these settings. Community-wide ivermectin-based mass drug administration (MDA) is an effective control strategy for scabies in island settings, with a single round of MDA reducing population prevalence by around 90%. However, current two-dose regimens present a number of barriers to programmatic MDA implementation. We designed the Regimens of Ivermectin for Scabies Elimination (RISE) trial to investigate whether one-dose MDA may be as effective as two-dose MDA in controlling scabies in high-prevalence settings. METHODS AND ANALYSIS: RISE is a cluster-randomised non-inferiority trial. The study will be conducted in 20 isolated villages in Western Province of Solomon Islands where population prevalence of scabies is approximately 20%. Villages will be randomly allocated to receive either one dose or two doses of ivermectin-based MDA in a 1:1 ratio. The primary objective of the study is to determine if ivermectin-based MDA with one dose is as effective as MDA with two doses in reducing the prevalence of scabies after 12 months. Secondary objectives include the effect of ivermectin-based MDA on impetigo prevalence after 12 and 24 months, the prevalence of scabies at 24 months after the intervention, the impact on presentation to health facilities with scabies and impetigo, and the safety of one-dose and two-dose MDA. ETHICS AND DISSEMINATION: This trial has been approved by the ethics review committees of the Solomon Islands and the Royal Children's Hospital, Australia. Results will be disseminated in peer-reviewed publications and in meetings with the Solomon Islands Ministry of Health and Medical Services and participating communities. TRIAL REGISTRATION DETAILS: Australian New Zealand Clinical Trials Registry: ACTRN12618001086257. Date registered: 28 June 2018.

Association between the spread of COVID-19 and weather-climatic parameters.

OBJECTIVE: To explore whether the climate has played a role in the COVID-19 outbreak, we compared virus lethality in countries closer to the Equator with others. Lethality in European territories and in territories of some nations with a non-temperate climate was also compared. MATERIALS AND METHODS: Lethality was calculated as the rate of deaths in a determinate moment from the outbreak of the pandemic out of the total of identified positives for COVID-19 in a given area/nation, based on the COVID-John Hopkins University website. Lethality of countries located within the 5th parallels North/South on 6 April and 6 May 2020, was compared with that of all the other countries. Lethality in the European areas of The Netherlands, France and the United Kingdom was also compared to the territories of the same nations in areas with a non-temperate climate. RESULTS: A lower lethality rate of COVID-19 was found in Equatorial countries both on April 6 (OR=0.72 CI 95% 0.66-0.80) and on May 6 (OR=0.48, CI 95% 0.47-0.51), with a strengthening over time of the protective effect. A trend of higher risk in European vs. non-temperate areas was found on April 6, but a clear difference was evident one month later: France (OR=0.13, CI 95% 0.10-0.18), The Netherlands (OR=0.5, CI 95% 0.3-0.9) and the UK (OR=0.2, CI 95% 0.01-0.51). This result does not seem to be totally related to the differences in age distribution of different sites. CONCLUSIONS: The study does not seem to exclude that the lethality of COVID-19 may be climate sensitive. Future studies will have to confirm these clues, due to potential confounding factors, such as pollution, population age, and exposure to malaria.

Development and validation of serological markers for detecting recent Plasmodium vivax infection.

A major gap in the Plasmodium vivax elimination toolkit is the identification of individuals carrying clinically silent and undetectable liver-stage parasites, called hypnozoites. This study developed a panel of serological exposure markers capable of classifying individuals with recent P. vivax infections who have a high likelihood of harboring hypnozoites. We measured IgG antibody responses to 342 P. vivax proteins in longitudinal clinical cohorts conducted in Thailand and Brazil and identified candidate serological markers of exposure. Candidate markers were validated using samples from year-long observational cohorts conducted in Thailand, Brazil and the Solomon Islands and antibody responses to eight P. vivax proteins classified P. vivax infections in the previous 9 months with 80% sensitivity and specificity. Mathematical models demonstrate that a serological testing and treatment strategy could reduce P. vivax prevalence by 59-69%. These eight antibody responses can serve as a biomarker, identifying individuals who should be targeted with anti-hypnozoite therapy.

Impact of Community Treatment With Ivermectin for the Control of Scabies on the Prevalence of Antibodies to Strongyloides stercoralis in Children.

The prevalence of antibodies to Strongyloides stercoralis was measured in 0-12-year-olds using a bead-based immunoassay before and after ivermectin mass drug administration (MDA) for scabies in the Solomon Islands. Seroprevalence was 9.3% before and 5.1% after MDA (P = .019), demonstrating collateral benefits of ivermectin MDA in this setting.