The American Journal of Tropical Medicine and Hygiene

The relationship between malaria entomological indices and epidemiological outcomes remains poorly understood at local scales in western Kenya, limiting evidence-based surveillance strategies. This study evaluated associations between vector densities, entomological inoculation rates (EIR), human biting rates (HBR), and malaria test positivity rates in a high-transmission setting. The study was conducted in five villages within Teso South sub-County, Busia County, Kenya, from March to June 2021. Village-level entomological indices including vector densities, human biting rates (HBR), and entomological inoculation rates (EIR) were calculated for Anopheles funestus and An. gambiae s.l. Concurrent malaria test positivity rates were obtained from outpatient department registers in the health facilities serving the five villages (n=2,377 cases). The relationship between entomological indices and malaria test positivity was analyzed using multilevel logistic regression models, accounting for individual- and village-level factors. During this period 1,957 female anopheline mosquitoes, predominantly An. gambiae s.l (89.17%) and An. funestus (10.48%) were collected. Malaria test positivity rates varied significantly across villages (range: 23.6%-68.7%). Multilevel analysis revealed significant associations between malaria test positivity and both anopheline mean density (OR 1.12, 95% CI 1.08-1.16, P<0.0001) and HBR (OR 1.37, 95% CI 1.19-1.57, P<0.0001). Age of humans showed a slight negative association with malaria positivity (OR 0.999, 95% CI 0.998-0.9997, P=0.013), while EIR showed no significant association (OR 1.04, 95% CI 0.96-1.13, P=0.319). Entomological indices, particularly vector density and human biting rate, showed strong associations with malaria test positivity rates. However, entomological monitoring is actually pretty intensive and covers only a few villages, and only parts of those, while routine surveillance for clinical cases of malaria is becoming increasingly reliable. These findings therefore suggest that one solution to higher malaria cases is target transmission through vector control. This information could be valuable for national malaria control programs in optimizing surveillance strategies and evaluating intervention effectiveness.

Cerebral malaria (CM) due to Plasmodium falciparum (Pf) infection is a major cause of death in African children. Bradykinin (BK) is a mediator of vasogenic edema. It could contribute to the pathogenesis of central nervous system malaria in Kenyan children and P. berghei ANKA (PbA) infected C57BL/6J mice with experimental cerebral malaria. Cleaved plasma high molecular weight kininogen (cHK) is a marker for prior BK release. 40% of children with central nervous system malaria had plasma cHK versus 18% of children with uncomplicated malaria. Wild-type PbA-infected mice had circulating plasma cHK, elevated BK levels, and reduced HK and prekallikrein levels. HK null (Kng1-/-), combined BK B1 and B2 receptor null (Bdkrb1-/- / Bdkrb2-/-), BK B2 (Bdkrb2-/-) or BK B1 (Bdkrb1-/-) receptor null mice were protected from neurologic deterioration and brain edema compared to wild-type mice. F12-/-mice were not protected from neurological deterioration. Prekallikrein null (Klkb1-/-), prolylcarboxypeptidase hypomorphs (Prcpgt/gt), and brain endothelial cell conditional knockout of PRCP (Prcpfl/fl Cre) mice had reduced neurologic deterioration and brain edema. Adjuvant plasma kallikrein inhibition combined with artesunate treatment of PbA-infected mice reversed neurologic deterioration and brain edema and prolonged survival relative to artesunate alone. BK-induced vasogenic edema contributes to human and murine CM.

BackgroundMalaria during pregnancy contributes to maternal anemia and adverse birth outcomes in sub-Saharan Africa. This study assessed seasonal malaria burden among pregnant women in Cape Coast, Ghana, during 2019-2021. MethodsRetrospective surveillance analysis of pregnant women attending Cape Coast Teaching Hospital. Malaria was diagnosed by microscopy, and hemoglobin levels were measured. Seasonal trends and demographic characteristics were analyzed using descriptive statistics and chi-square tests. ResultsAmong 334 pregnant women, 294 (88.0%) were tested for malaria. Overall prevalence was 2.04% (6/294; 95% CI: 0.75-4.41%), exclusively Plasmodium falciparum. Prevalence was higher in the dry season (2.26%) than wet season (1.27%), with 67% of cases in Q4 2021. Mean age was 35.0 {+/-} 5.1 years, and 79.4% presented in third trimester. Anemia (Hb <11 g/dL) affected 41.3% of participants despite low malaria prevalence. Sensitivity analyses confirmed robust estimates across analytical approaches. ConclusionsLow malaria prevalence reflects progress toward Ghanas elimination goals, though the unexpected dry season pattern warrants investigation. High anemia burden despite low malaria indicates non-malarial causes require attention. Year-round screening and comprehensive antenatal care remain essential as Ghana transitions toward elimination.

This cross-sectional study assessed hygienic practices, microbial contamination, and associated factors among street food vendors in Mymensingh City, Bangladesh, from August 2024 to February 2025. Using purposive sampling, 300 vendors were evaluated through structured questionnaires, observational assessments, and laboratory analysis of food samples (n = 300) for bacterial load (log-transformed Total Viable Count, log_TVC). Results revealed that 87.33% (95% CI: 83.6-91.1) of vendors practiced poor hygiene: 90.7% (95% CI: 87.4-94.0) did not cover food, 7% (95% CI: 4.1-9.9) used disinfectants, and 81.00% (95% CI: 76.6-85.4) reused ingredients beyond one day. Knowledge gaps were stark, with 89.7% (95% CI: 86.3-93.1%) demonstrating insufficient basic hygiene knowledge and 90.7% (95% CI: 87.4-94.0%) lacking understanding of hygienic food processing. Education significantly influenced practices; secondary-educated vendors exhibited markedly better hygiene awareness (65.0% vs. 2.89% in uneducated groups). Bacterial loads varied across food types, with Velpuri showing the highest mean log_TVC (8.00, 95% CI: 7.65-8.35) and fast food the lowest (7.69, 95% CI: 7.34-8.03). Significant correlations emerged between hygiene knowledge and practices: vendors aware of foodborne diseases were more likely to use gloves (Spearman's r = 0.199, p = 0.001) and cover food (r = 0.118, p = 0.041). Challenges included financial constraints (62.25% [95% CI: 56.1-68.4] among uneducated vendors), knowledge gaps, and time limitations. The study underscores systemic issues in street food safety, driven by low education and economic barriers. Interventions targeting vendor education, affordable hygiene solutions, and stricter enforcement of ingredient freshness protocols are urgently needed to mitigate foodborne disease risks in urban Bangladesh.

BackgroundCambodia has made great progress in reducing malaria transmission and is targeting elimination. While this progress is particularly marked for Plasmodium falciparum, the situation is different for Plasmodium vivax. It is generally assumed that symptomatic patients are effectively diagnosed using rapid diagnostic tests (RDTs), regardless of transmission intensity. MethodsIn 2023 we conducted a cross-sectional survey among 986 treatment-seeking patients in 6 provinces of Cambodia with varying reported malaria cases. Malaria RDT (Pf/Pv), microscopy and qPCR diagnostics of Plasmodium infections and species determination were performed. ResultsUsing qPCR, Plasmodium infections were diagnosed in 156 patients (15.8%, 95% CI: 13.7-18.2%) from all 6 provinces. Positivity rate was markedly different between health centers (HCs) and ranged between 57.2% and 0.5%. Parasitemia of infected patients was different between HCs and was lower in HCs with the lowest positivity rate compared to those with higher rates. The majority of Plasmodium infections (75%) were caused by P. vivax, however all human malaria species were identified as well as the simian parasite P. knowlesi. Overall sensitivity of RDTs to detect Plasmodium infections was 39.7% (95% CI: 28.9-51.6%) and specificity was 100% (95% CI: 99.5-100%). The proportion of RDT true positives was significantly different between HCs, and a tendency for higher false negative rates in low transmission areas compared to higher ones was observed. ConclusionWhile our results confirm that P. falciparum parasites are nearly eliminated from Cambodia, we show that current practice for diagnosis of Plasmodium infections among febrile patients is challenged, especially in very low transmission settings.

Background: Dengue emerged as a new public health threat in the Rohingya refugee camps in Coxs Bazar, Bangladesh, in 2021 and expanded into large-scale upsurges in subsequent years. Evidence on dengue epidemiology and clinical presentation in protracted refugee settings remains limited, despite the need for stronger outbreak preparedness and case management in these contexts. Objectives: To describe the epidemiological, clinical, and diagnostic characteristics of the dengue upsurge among Rohingya refugees and surrounding host communities in Coxs Bazar, Bangladesh, and to identify predictors of inpatient admission and diagnostic positivity patterns. Methods: This retrospective observational study used anonymized surveillance data from the International Organization for Migration (IOM) dengue patient database. Rapid diagnostic test (RDT)-confirmed dengue cases identified across 36 IOM-supported health facilities in Ukhiya and Teknaf between 1 October 2021 and 31 December 2024 were included. Demographic, epidemiological, clinical, and laboratory variables were summarized using descriptive statistics. Weekly incidence was aggregated by epidemiological week and calendar year, and epidemic growth and decay phases were modelled using phase-specific Poisson regression. Multivariable logistic regression was used to identify predictors of inpatient admission and to examine associations between delay in presentation and RDT positivity patterns, adjusting for age and sex. Results: A total of 35,581 RDT-confirmed dengue cases were reported, of which 90.2% occurred among Rohingya refugees. The median age was 17 years (IQR 7-30), and 46.0% of cases were among children aged 0-14 years. Annual caseload increased from 1,011 in 2021 to 11,752 in 2022, 10,669 in 2023 and 12,149 in 2024, with seasonal peaks during the monsoon period and progressively later peaks and longer epidemic tails over time. Poisson models showed decreasing growth rates across years (r=0.449 in 2021 to r=0.091 in 2024) with increasing doubling times, while decay rates remained broadly comparable (halving time ~4.4-6.0 weeks). Overall, 8.0% of cases required inpatient admission, 1.3% were referred, and four deaths were reported (case fatality <0.1%). In multivariable analysis, inpatient admission was associated with older age ([&ge;]60 vs 0-14: aOR 2.31), delayed presentation (aOR 1.06 per day), refugee status (aOR 1.39), presence of any World Health Organization (WHO) warning sign (aOR 26.60), low systolic BP (aOR 2.84) and chronic co-morbidity (aOR 6.07). In addition, males had lower odds of admission than females (aOR 0.88). NS1 antigen alone was positive in 62.1% of cases, IgM alone in 33.6%, and dual positivity in 4.3%. Longer delay from symptom onset to presentation was strongly associated with IgM-only positivity compared with NS1-only positivity (adjusted models controlling for age and sex). Conclusion: Sustained dengue preparedness is required in Coxs Bazar, including strengthened surveillance, community-based early referral, targeted monitoring of high-risk groups, environmental vector control, and phase-appropriate use of NS1 and IgM/IgG diagnostics to reduce missed diagnoses and prevent progression to severe disease. These findings highlight the need for a policy shift from episodic outbreak response toward sustained dengue preparedness in humanitarian settings, including strengthened surveillance systems, integrated diagnostic strategies, community-based early referral, and coordinated vector control interventions.

BackgroundPlasmodium vivax (P. vivax) has emerged as the primary cause of malaria in Cambodia. Achieving malaria elimination and securing malaria-free certification requires a focused effort on addressing P. vivax malaria. This is essential because the elimination of P. vivax often lags behind that of Plasmodium falciparum, making it a critical component in the overall strategy. This study assesses the feasibility of the Mass Drug Administration (MDA) and P. vivax Serological Testing and Treatment (PvSeroTAT) integrated with Reactive Case Detection (RACD) in two of the highest malaria burden operational districts of Cambodia and examines the potential for integrating these two approaches with existing malaria elimination efforts. MethodsThis study employs an observational, prospective cohort design. MDA with chloroquine (CQ) will be conducted in Stung Treng through four monthly rounds, while RACD with PvSeroTAT will be implemented in Sen Monorom, targeting households near confirmed P. vivax cases. Data on coverage, compliance, cost, and stakeholder perceptions will be collected through surveys, interviews, and malaria case monitoring. A Composite Feasibility Index will integrate quantitative and qualitative indicators. Cost and budget impact analyses will assess scalability for malaria-endemic districts. DiscussionInnovative and targeted public health approaches and tools are necessary to ensure the elimination of the malaria parasite reservoir, including the hidden hypnozoites. While MDA with CQ clears active blood-stage infections leading to immediate reductions in malaria prevalence, PvSeroTAT can detect past exposure to P. vivax by using serological markers allowing for targeted treatment of individuals at risk of developing relapsing infections with an 8-aminoquinoline. This helps reduce the parasite reservoir more efficiently. This study will provide insight into operational feasibility, implementation costs, community acceptance, and long-term sustainability. The findings will guide Cambodias malaria elimination efforts through improved surveillance and targeted interventions. Trial RegistrationOSF Preregistration: https://doi.org/10.17605/OSF.IO/5KZH7, retrospectively registered 15 October 2025.

Background Approximately 59,000 cases and 1700 deaths were reported during the 2022-2023 cholera outbreak in Malawi. In response, the Ministry of Health implemented Oral Cholera vaccination campaigns (OCV) as one of the interventions. Four series of single-dose reactive OCV campaigns were conducted in 21 health districts between May 2022 and September 2023. OCV survey report of 2023 estimated a coverage of 55.40%. It was barely known how a single dose of OCV interrupts community transmission. This study was conducted to provide evidence on the use of a single-dose strategy and its contribution towards reducing the risk of cholera infection. Method A cross-sectional quantitative analysis was conducted to assess the effectiveness of OCV in reducing cholera incidence, severity, and mortality during the 2022-2023 cholera outbreak in Malawi. A national cholera line-list was used for analysis. Results Oral cholera vaccination coverage was at 2.0% of 28,920 suspected cholera cases. The effectiveness of a single dose of OCV towards reducing cholera infections was 98.00%. and associated with lower odds of severe dehydration (OR = 0.50; 95% CI: 0.39-0.64), with OCV effectiveness at 50%(95% CI: 36-61) Case fatality rate among vaccinated was 1.20 (95% CI: 0.54; 2.6, p = 0.025) and among unvaccinated it was 2.80% (95% CI: 2.6; 3.0, p = 0.025). Conclusion A single dose of the OCV campaign conducted during the 2022-2023 cholera outbreak in Malawi contributed to the reduction of cholera incidence. The intervention complemented other long-term interventions such as Water, Sanitation and Hygiene Oral Dehydration Points, Case Area Targeted Intervention, and Risk Communication and Community Engagements.

Abstract Background In many countries, particularly in sub-Saharan Africa, medical pluralism and utilization of multiple therapeutic approaches for managing diseases, including malaria, are common. Ghana's antimalarial medicine policy has recommended herbal medications for treating uncomplicated malaria. While this is in line with complementary and alternative medicine (CAM) use for the treatment of malaria, exploring CAM for malaria prevention could be an important consideration for public health initiatives towards malaria elimination efforts. This study assessed the prevalence, perceptions, and attitudes on CAM use for malaria prevention in the general population and associated factors. Methods A community-based cross-sectional analytic survey was conducted among 3064 adult residents sampled between September and November 2023. A multi-stage sampling method was used to select participants from 18 sub-districts drawn from 6 districts and 6 regions in Ghana. Data on CAM use for malaria prevention, attitudes about CAM, perceptions about malaria, and sociodemographic factors were collected. The primary outcome was reported CAM use for malaria prevention within the 12months preceding the survey, measured as a binary outcome. Multiple logistic regression analyses were performed to identify the predictors of CAM use for malaria prevention. Results A total of 3,064 household respondents were involved in the analysis, with 51.2% (n=1,570) females and a median age of 31 years (IQR: 24-42 years). The use of CAM for malaria prevention in the last 12 months was 31.6% (95% CI: 30.0-33.3%). The most common types of CAM used included botanical/herbal medicine (21.8%), vitamin supplements (12.3%), mineral supplements (10.7%), and spiritual healing/prayers (9.6%). Increased CAM use for malaria prevention was associated with education and perceptions, such as concerns and consequences about malaria. Factors associated with decreased odds of CAM use included formal employment and having a skeptical and indifferent attitude about CAM. Conclusion Over a third of the population used CAM for malaria prevention in the last year, highlighting its role in public health. Integrating herbal medicine into prevention strategies could enhance community acceptance and help with efforts toward malaria elimination. However, further research is needed to validate clinical efficacy, establish potential drug-herb interactions, and isolate lead compounds for optimized malaria prevention therapy.

Chronic hepatitis B and hepatitis C remain major public health concerns in the WHO European Region, where an estimated 10.6 million people were living with HBV infection and 7.7 million with HCV infection in 2022. Despite this substantial burden, diagnosis and treatment coverage remain low, posing a significant challenge to achieving the WHO regional goal of viral hepatitis elimination by 2030. To assess country-level progress and gaps in hepatitis testing and treatment, the WHO Regional Office for Europe conducted a survey among nine high burden countries, receiving responses from eight: Armenia, Azerbaijan, Belarus, Kazakhstan, Kyrgyzstan, the Republic of Moldova, Turkmenistan and Uzbekistan. The survey examined national policies, testing availability, treatment regimens, service delivery approaches, and key implementation barriers. Most countries reported having national HBV and HCV guidelines aligned with international standards, although planned updates were inconsistent. Point of care PCR viral load testing was available in five countries, but coverage of test costs varied, and reflex PCR testing had been implemented in only four. First line antiviral regimens largely followed international guidance; however, medication prices and national coverage differed considerably, with out of pocket payment requirements persisting in several settings. All countries reported the use of non invasive tests for liver disease staging, though coverage for elastography remains limited. Service delivery has become increasingly decentralized, with HBV and HCV testing and care available across multiple levels of the health system and integrated into primary care and HIV clinics in most countries. Nevertheless, provision of HCV treatment in harm reduction settings remains rare, limiting access for populations at highest risk. Overall, the findings indicate strong political commitment but highlight persistent gaps in testing access, treatment affordability, and service delivery models. Addressing these gaps through tailored country specific strategies, expanded financial protection, and strengthened integration of services will be essential to accelerate progress toward the 2030 elimination targets.

Persistent, asymptomatic Plasmodium infections are common in areas of high transmission due to acquired immunity. When asymptomatically infected individuals seek care for a fever caused by something other than malaria parasites, they may test positive for parasites and be incorrectly diagnosed as having clinical malaria. This study used distributions of qPCR parasite densities to estimate the fraction of fever attributable to malaria (malaria attributable fraction, MAF) in a cohort of 659 individuals followed for up to 3 years from three geographically distinct zones in eastern Uganda. Prevalence of P. falciparum by qPCR ranged from 47-63% in the three zones, with over 95% of cohort members parasitemic at least once. Overall MAF across the three zones ranged from 54-64%. MAF was highest in under-five year-olds (72%), next highest in 5-15 year-olds (56%) and lowest in adults over 16 (45%). Notably, nearly 50% of fevers with low to moderate parasite density (10 - 100 parasite/ microliter) were attributed to malaria. MAF-corrected incidence was higher than the definition of clinical malaria used in many vaccine field-studies (fever and parasite density [&ge;] 5000/microliter) and the difference varied by age group: MAF-corrected incidence was 18% higher in children under five, 7% higher in 5-15 year olds, and 70% higher in adults. These results suggest parasite density thresholds commonly used to define primary study outcomes will underestimate the true incidence of clinical malaria. Studies aiming to precisely estimate intervention effects on incidence should consider estimating MAF in their study population and incorporating it into their design.

BackgroundMalaria, transmitted by female Anopheles mosquitoes, remains a major public health challenge in Nigeria, where approximately 97% of the population is at risk. Despite large-scale investments, Nigeria continues to bear the worlds highest malaria burden. Long-lasting insecticidal nets (LLINs) are central to prevention, yet their effectiveness is increasingly undermined by non-usage, delayed replacement, and growing outdoor biting activity. National surveys (MIS, PMI) consistently report gaps in LLIN use, irregular implementation of the three-year replacement strategy, and persistent outdoor biting. This study quantifies the relative contributions of these behavioural and entomological factors to sustained malaria transmission across five Nigerian states. MethodsA deterministic compartmental model of malaria transmission was developed and calibrated using Bayesian inference with MCMC in CmdStanR. The model incorporated heterogeneous mosquito biting behaviour, LLIN effectiveness decay, and distribution cycles. Calibration used monthly malaria case data (2015-2024), demographic and entomological data (2015-2022), and DHS/MIS prevalence surveys (2015, 2018, 2021) for Akwa Ibom, Ebonyi, Kebbi, Oyo, and Plateau states. Counterfactual scenarios quantified malaria cases attributable to (i) outdoor mosquito biting, (ii) LLIN usage gaps, and (iii) delayed replacement. Parameter sweeps were used to assess how LLIN effectiveness changes with varying outdoor biting intensities. ResultsEliminating outdoor biting yielded the largest reductions in malaria incidence--Akwa Ibom (82.4%, 95% CrI: 74.0-89.6), Ebonyi (92.0%, 95% CrI: 87.5-95.5), Kebbi (76.4%, 95% CrI: 51.0-92.6), and Oyo (83.0%, 95% CrI: 74.9-89.6). LLINs sub-stantially reduced malaria transmission only under low outdoor biting intensities--below 1 bite per mosquito per month in Akwa Ibom and Ebonyi, below 0.2 in Kebbi and up to 0.8 in Oyo. In Plateau, outdoor biting contributed minimally (5.8%, 95% CrI: 4.8-6.3), while the gap between LLIN ownership and use was the dominant factor (23.1%, 95% CrI: 22.5-23.8), rising to 36.5% (95% CrI: 35.5-37.6) when combined with delayed replacement. ConclusionOutdoor mosquito biting is a dominant driver of persistent malaria transmission in Akwa Ibom, Ebonyi, Kebbi, and Oyo states, whereas low LLIN usage is the leading factor in Plateau. Although maintaining high LLIN coverage, adherence, and timely replacement remains critical, these efforts alone are insufficient where outdoor biting is widespread. Strengthening Nigerias malaria control strategy will require integrating LLIN deployment with targeted outdoor vector control and state-specific behavioural interventions to achieve sustained reductions in malaria burden.

BackgroundDengue virus (DENV) is an increasingly recognized cause of febrile illness in sub-Saharan Africa, yet its epidemiology in Nigeria remains incompletely characterized due to fragmented surveillance and diagnostic variability. We conducted a systematic review and meta-analysis to estimate marker-specific seroprevalence and to evaluate geographic variation, seasonal patterns, and environmental risk factors associated with DENV infection in Nigeria between 2014 and 2024. MethodsFollowing PRISMA guidelines, we searched PubMed, Scopus, Web of Science, EMBASE, Google Scholar, and African Index Medicus for studies reporting laboratory-confirmed dengue infection in Nigeria. Random-effects meta-analysis was used to estimate pooled prevalence and pooled odds ratios (ORs) with 95% confidence intervals (CIs). Between-study heterogeneity was quantified using the I{superscript 2} statistic. Subgroup analyses explored variation by diagnostic marker and geographic region. ResultsThirty-three studies met inclusion criteria. The pooled random-effects IgM seroprevalence was 20.9% (95% CI: 13.0-30.1; I{superscript 2} = 98.6%), while pooled IgG seroprevalence was 19.9% (95% CI: 11.6-29.7; I{superscript 2} = 97.7%). NS1 antigen positivity was 8.9% (95% CI: 2.2-19.4), and PCR-confirmed infection was 7.0% (95% CI: 1.2-16.2; I{superscript 2} = 25.8%). Significant differences were observed across diagnostic markers (p = 0.0002). Regional subgroup analysis demonstrated statistically significant geographic variation for both IgM (p = 0.0179) and IgG (p = 0.0030), with highest pooled prevalence observed in the Southeast and lowest in the Southsouth region. Environmental and behavioral exposures were strongly associated with seropositivity, including proximity to refuse dumpsites (OR = 9.39, 95% CI: 7.44-11.84), non-use of mosquito nets (OR = 8.70, 95% CI: 5.73-13.21), malaria positivity (OR = 5.54, 95% CI: 3.84-7.98), and open household water storage (OR = 2.18, 95% CI: 1.65-2.89). All four DENV serotypes were identified across reporting studies. Transmission intensity increased during rainy seasons. ConclusionsDengue virus transmission in Nigeria is widespread and geographically heterogeneous, with evidence of both recent and cumulative exposure. Strong associations with modifiable environmental and household-level factors underscore the importance of integrated vector control and improved diagnostic capacity. Enhanced surveillance and climate-informed public health strategies are essential to mitigate future outbreak risk. Author SummaryDengue is a mosquito-borne viral infection that is increasing globally but remains underrecognized in much of sub-Saharan Africa. In Nigeria, many febrile illnesses are presumed to be malaria, which can obscure the contribution of dengue virus infection. In addition, limited surveillance systems and inconsistent diagnostic testing have made it difficult to determine the true extent of dengue transmission. To address this gap, we conducted a systematic review and meta-analysis of studies published between 2014 and 2024 to evaluate patterns of dengue exposure, geographic variation, and environmental risk factors in Nigeria. We found evidence of both recent infection (IgM antibodies) and past exposure (IgG antibodies) across multiple regions of the country. Transmission intensity varied geographically, with higher levels observed in some regions, particularly in the Southeast, and lower levels in the Southsouth. Infection risk increased during the rainy season, consistent with enhanced mosquito breeding conditions. Living near refuse dumpsites, storing water in open containers, not using mosquito nets, and having malaria were all associated with higher odds of dengue infection, highlighting the importance of household and environmental conditions in shaping transmission risk. All four dengue virus serotypes were identified, indicating sustained viral circulation. These findings demonstrate that dengue virus infection is widespread in Nigeria and influenced by modifiable environmental and behavioral factors. Improving diagnostic capacity, strengthening routine surveillance, and implementing targeted vector control strategies are essential to reduce transmission and improve outbreak preparedness.

Background: Malaria remains a major global health threat, with 249 million cases and 609,000 deaths reported in 2022. The Ashanti Region of Ghana bears a disproportionate burden, with severe malaria accounting for 24% of hospital admissions in 2021, above the national average of 19%. Despite intensified control efforts, inpatient mortality patterns remain poorly understood. This study identifies key determinants of severe malaria mortality among hospitalized patients in the Ashanti Region. Methods: We analyzed inpatient surveillance data from the District Health Information Management System 2 (DHIMS2) for severe malaria admissions from 2018 to 2022. Descriptive statistics, bivariate analyses with robust survey estimation (accounting for design effects), and multivariable Firth penalized logistic regression were used to identify mortality predictors. Survey-adjusted logistic regression served as a sensitivity analysis to validate findings. Results: Among 54,544 severe malaria admissions, females comprised 51.1% and children under five 39.4%. The case fatality rate was 0.4% (200 deaths). Mortality was significantly associated with age, occupation, insurance status, facility ownership, admitting department, length of stay, and comorbidities. Males had 1.4 times higher mortality odds than females. Compared to children under five, patients aged 5 to 17 years had 44% lower odds of mortality (aOR = 0.56, 95% CI: 0.33, 0.94). Active NHIS membership had lower mortality odds by 67% (aOR=0.33, 95% CI: 0.25, 0.45) compared to inactive membership. Admissions to faith-based facilities showed lower mortality odds (aOR=0.38, 95% CI: 0.23, 0.65) than government facilities, while medical wards had higher odds (aOR=2.38, 95% CI: 1.48, 3.84) than paediatric wards. Stays of 3 to 5 days were associated with lower mortality odds (aOR=0.67, 95% CI: 0.47, 0.97) compared to stays <3 days. Those with comorbidities had twice the mortality odds versus those without. Sensitivity analysis confirmed consistent direction and significance. Conclusion: Age, comorbidities, insurance coverage, facility type, and admission practices strongly influence severe malaria mortality in Ashanti. Strengthening NHIS enrollment, extending inpatient monitoring beyond three days, and adopting best practices from paediatric and faith based facilities could improve survival. Integrating comorbidity screening and management into malaria protocols is essential to reducing preventable deaths.

Background: Household insecticides are widely used for domestic pest control, yet exposure patterns in traditionally underserved populations remain poorly characterized. In the Brazilian Amazon, data on use patterns among older adults living in riverine communities are particularly scarce. Objective: To describe the prevalence, frequency, duration, application practices, and types of household insecticides used by older adults living in near-urban riverine insular communities in the Brazilian Amazon. Methods: Cross-sectional, population-based door-to-door survey conducted from August 2022 to July 2025 in four islands (Cotijuba, Mosqueiro, Outeiro, and Combu) in the city of Belem, Brazil. All residents aged 60 years or more registered in the primary care system were invited to participate. Trained interviewers administered an in-person standardized questionnaire to participants on current household insecticide use, frequency, duration, self-application, protective equipment, insecticide types, and product brands. Results: Among 1,101 screened individuals, 1,084 were included (median age at evaluation: 68 years). Overall, 78.4% reported current use of household insecticides. Weekly or more frequent use was reported by 58.9%, and 33.4% reported use for more than 5 years. Self-application was common (57.5%), whereas use of protective equipment was rare (8.2%). Aerosol sprays were the most frequently reported type (39.4%). Commonly recalled aerosols contained pyrethroid mixtures including cypermethrin, imiprothrin, prallethrin, and transfluthrin. A substantial proportion of participants reported using unregulated products and veterinary-only insecticides for household purposes. Conclusions: Household insecticide use is highly prevalent and frequent in Amazonian riverine communities, with minimal use of protective equipment and substantial irregular practices, underscoring the need for targeted risk communication and surveillance.

ObjectivesDespite the availability of effective vaccines, achieving the seroprevalence thresholds recommended by the World Health Organization (WHO) for eliminating measles, rubella, and mumps remains a public health challenge. MethodsA retrospective, cross-sectional serological survey was conducted, including 9,587 serum samples collected from 31 of the 32 federal entities of Mexico between September and December 2024. IgG antibody levels against measles, rubella, and mumps were quantified using chemiluminescent immunoassays. Seroprevalence was analyzed by age, sex, and geographic region. ResultsThe overall seroprevalence was 78.3% for measles, 88.6% for rubella, and 81.5% for mumps (p<0.05). Age-stratified analysis revealed significant gaps in immunity against measles and mumps, particularly in the 10-39-year-old group, in which seroprevalence dropped below 70%. In contrast, more consistent protection against rubella was observed across all age groups, although younger children showed lower antibody titers. Regional analysis indicated that only older adults reached the protective threshold against measles in all states. ConclusionsThis study demonstrates that current levels of seroprevalence in Mexico do not correspond to the vaccination coverage recommended by the WHO and highlights the urgent need to strengthen vaccination strategies, conduct catch-up campaigns, and carry out continuous seroepidemiological surveillance to maintain elimination goals.

ObjectiveTo estimate dengue virus (DENV) seroprevalence and assess parental vaccine perceptions among children in the US Virgin Islands (USVI). MethodsA cross-sectional serosurvey was conducted during April-May 2022 among 372 children aged 8-16 years from 15 schools across USVI. Past DENV infection was determined using a dengue IgG rapid diagnostic test. Data on demographics, dengue knowledge, and vaccine acceptance were collected from parents. Catalytic models estimated annual DENV force of infection (FOI) using seroprevalence and case data from 2010-2022. ResultsSeroprevalence among children aged 8-13 years was 47% (95% CI: 29%, 68%). FOI peaked during 2012-2013 outbreaks and remained low in other years. Only 17% of parents were aware of an approved dengue vaccine, and 25% reported they would vaccinate their child. ConclusionsNearly half of children had prior DENV infection. Despite this risk, parental awareness of dengue vaccination was low, underscoring gaps in detection, diagnosis, and preparedness for vaccine implementation. Policy ImplicationsThese data highlight the need for enhanced surveillance, public education, and targeted planning for dengue vaccine introduction in endemic US jurisdictions.

Background Malaria remains a critical global health challenge, with over 68% of Ethiopias population living in at-risk areas. While Long-Lasting Insecticidal Nets (LLINs) are a cornerstone of prevention, their effectiveness depends on consistent use. This study aimed to assess LLIN ownership and utilization patterns and identify socio-behavioral and physical determinants of their effectiveness in endemic communities. Methods A community-based, cross-sectional survey was conducted from October 2024 to January 2025 across 11 administrative regions in Ethiopia. Using a two-stage stratified cluster sampling technique, data were collected from 9,222 households (34,427 individuals) through face-to-face interviews and direct physical observations. Data analysis was performed using the SPSS Complex Samples module and hierarchical multivariable logistic regression. Results The survey found a household LLIN ownership rate of 71.5%, while the proportion of sufficient LLINs for every two people was 58.3%. Among those who owned nets, the overall utilization rate was 59.9%, with significantly higher rates in rural areas (72.7%) than in urban areas. Vulnerable groups achieved higher usage levels, specifically pregnant women (78.5%) and children under five (67.2%). Multivariable analysis indicated that age and pregnancy status were the strongest predictors of LLIN use, with ORs of 0.258 (p < 0.001) and 0.662 (p < 0.001), respectively. Major barriers identified included a 60.5% lack of confidence in hanging nets (p < 0.001) and a widespread misconception (64.1%) that malaria risk is restricted to the rainy season. Conclusion Although Ethiopia has made strides in LLIN ownership and prioritized protection for vulnerable demographics, overall utilization remains below the 80% threshold required for community-wide protection. To bridge the gap between ownership and consistent use, national strategies should transition toward skill-based interventions and targeted communication to address practical barriers and seasonal misconceptions.

BackgroundSevere Plasmodium falciparum malaria is a leading cause of death in sub-Saharan Africa, with most deaths occurring in children younger than five years of age. The RTS,S/AS01E (RTS,S) malaria vaccine delivered seasonally with Seasonal Malaria Chemoprevention (SMC) led to a two-third reduction in severe malaria and malaria deaths compared with either intervention given alone. The aim of this study was to assess the seasonal distribution and clinical presentation of children admitted in hospital with severe malaria who received RTS,S with or without SMC, and whether seasonal vaccination with RTS,S affected their distribution and clinical presentation. MethodsWe conducted a secondary ad-hoc analysis of hospital admissions in children aged 5 to 17 months of age when enrolled in the RTS,S + SMC trial in April 2017 in Hounde, Burkina Faso, and Bougouni, Mali, and who were followed until they reached five years of age. ResultsThree hundred and thirtythirty-seven serious adverse events were reported during the trial with 222 (65.9%) in Burkina Faso and 115 (34.1%) in Mali, and 48.1% (162/337) were due to severe malaria. The mean age of children with severe malaria was 2.9 years; 79.0% (128/162) of the cases occurred in children aged 3 years or less and 21.0% (34/162) in those aged 4 to 5 years. The most common presentation was severe anemia reported in 50% (81/162) of children, followed by repeated convulsions 25.3%, (41/162), prostration 11.1%, (18/162), hyperparasitaemia 8.0%, (13/162) and cerebral malaria 6.2%, (10/162). Severe malaria anemia was a more frequent form of severe malaria in children in the SMC alone arm 62.1%, (36/58) and lower in children in the SMC+ RTS,S arm 37.1%, (13/35), p=0.048. There was no significant difference in frequency of other clinical presentations between the study arms. Most severe malaria cases, 85.8% (139/162) occurred during the transmission season (July to December). ConclusionsSevere anaemia was the most common presentation of severe malaria and was most frequent in the SMC alone arm. Children aged 3 years or less were the most affected and almost all the cases occurred between July and December. Trial registrationClinicalTrials.gov, NCT04319380

BackgroundSpatial emanators disrupt mosquito behaviour by inducing movement away from chemical stimuli and interfering with host detection and feeding. These tools were recently endorsed by the World Health Organization (WHO) for malaria control, based largely on clinical evidence from East Africa. Mosquito ShieldTM is a passive, transfluthrin-based emanator designed to provide month-long protection in enclosed or semi-enclosed spaces. This study evaluated its entomological efficacy under experimental hut conditions in Benin, West Africa to generate evidence in support of WHO prequalification. MethodsAn experimental hut trial was conducted against wild free-flying pyrethroid-resistant Anopheles gambiae s.l. at the Cove field station in southern Benin over two 32-day product life cycles of Mosquito ShieldTM. Sixteen West African-style experimental huts were assigned to Mosquito ShieldTM or a placebo control. Efficacy was measured using human landing catches (HLC) and mosquito aspirations following standard hut testing methods. Primary endpoints included protective efficacy against mosquito landing (HLC) and personal protection against blood-feeding (mosquito aspiration). Secondary endpoints included deterrence, exophily, mortality, and blood-feeding inhibition. WHO susceptibility bioassays were conducted on the local An gambiae s.l. population to investigate susceptibility to public health insecticides during the trial. ResultsWHO susceptibility bioassays confirmed high levels of resistance to pyrethroids, including transfluthrin, in the local Anopheles gambiae s.l. population. A total of 5,682 An. gambiae s.l. and 6,158 Mansonia africana were collected through HLCs, and 1,436 An. gambiae s.l. by mosquito aspirations. Mosquito ShieldTM significantly reduced mosquito landing, providing 43.0% protective efficacy (95% CI: 24.0-57.0; p < 0.001) against An. gambiae s.l. and 38.0% protective efficacy (95% CI: 12.0-57.0; p = 0.008) against Mansonia africana. Mosquito aspiration data showed 48.5% deterrence, 29.9% blood-feeding inhibition, and 64% personal protection (95% CI: 21.9-81.8; p < 0.001) against An. gambiae s.l. No mosquito mortality was observed in the control huts, whereas mortality of An. gambiae s.l. reached 49.0% in HLC collections and 22.7% in aspiration collections. Mosquito ShieldTM also induced >96% mortality in Mansonia africana, demonstrating both lethal and behavioural effects against both vector species. ConclusionsMosquito ShieldTM significantly reduced mosquito entry, landing, blood-feeding, and survival of pyrethroid-resistant An. gambiae s.l. under semi-field experimental hut conditions in West Africa, with additional effects against Mansonia africana. These results support its WHO prequalification and highlight its potential as a complementary vector control tool to strengthen malaria prevention and provide additional benefits for integrated control of other vector-borne diseases.