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The American Journal of Tropical Medicine and Hygiene

American Society of Tropical Medicine and Hygiene

Preprints posted in the last 30 days, ranked by how well they match The American Journal of Tropical Medicine and Hygiene's content profile, based on 60 papers previously published here. The average preprint has a 0.17% match score for this journal, so anything above that is already an above-average fit.

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Last Mile elimination activities in Cambodia, October 2019 to December 2023

Filip, E.; Sovannaroth, S.; Kugler, A. M.; Brindle, H.; Ngor, P.; Chhun, B.; Ringwald, P.; Zhang, Z.; Rekol, H.

2026-05-18 public and global health 10.64898/2026.05.12.26353080 medRxiv
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Between 2015 and 2025, Cambodia reported a 99.9% decline in the number of cases of malaria. To aid acceleration of elimination, the National Center for Parasitology, Entomology and Malaria Control (CNM) implemented a package of interventions known as the Last Mile (LM) elimination program. The aim of this study was to determine the impact of the LM program on case numbers and evaluate the coverage of interventions. LM was rolled out between November 2020 and December 2023 in villages reporting a locally acquired case of Plasmodium falciparum or mixed infection with P. falciparum and P. vivax and included combinations of targeted drug administration (TDA), intermittent preventative treatment for forest goers (IPTf), active fever screening (AFS), the recruitment of a village or mobile malaria worker (VMW/MMW) and the top-up of insecticide-treated bed nets (ITN) depending on the vulnerability and receptivity of the village. A total of 103 full and 82 partial villages in seven provinces were included. Two rounds of TDA were administered, with a total of 10,678 individuals (67.6%) given during the first round and 9,678 (62.3%) during the second round. Coverage varied by province with none meeting the recommended threshold of 80%. IPTf was implemented each month among 35% (n=35) of full LM villages and 56% (n=42) of partial LM villages. A total of 11.7% (n=12) of full LM villages implemented AFS consistently on a weekly basis. Controlled interrupted time series showed no statistically significant difference in the number of malaria cases before and after the implementation of LM. Although we were unable to prove a statistically significant impact of LM, likely due to the small number of cases prior to LM, it is important to add to the limited evidence-based for Accelerator Strategies in countries approaching the elimination of malaria. Furthermore, findings from the feasibility and impact of individual interventions were used to change policy at the national level.

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Direct and Indirect Entomological Efficacy of Targeted Indoor Residual Spraying against Aedes aegypti in Iquitos, Peru

Astete, H.; Vasquez, G. M.; Lopez, V.; Zambrano, B.; Reyna, B.; Moore, R. C.; Morrison, A. C.; Vazquez-Prokopec, G. M.; Larson, R. T.

2026-05-18 ecology 10.64898/2026.05.18.725931 medRxiv
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BackgroundControl of Aedes aegypti, the primary vector of dengue and other Aedes-borne viruses, is challenged by insecticide resistance, limited efficacy of existing tools and the large and widespread epidemics. Targeted Indoor Residual Spraying (TIRS), a modification of traditional indoor residual spraying focused on Ae. aegypti resting sites, has demonstrated promising results, yet its indirect community-wide effects remain underexplored. Methodology/Principal FindingsWe conducted an entomological cluster-randomized controlled trial in Iquitos, Peru, to evaluate the direct and indirect entomological impacts of TIRS using pirimiphos-methyl. Thirty clusters were randomized to receive either TIRS (15 clusters, 898 structures) or standard Ministry of Health vector control activities (15 clusters, 1,018 structures). Aedes aegypti indoor densities were assessed in the 45 days pre-intervention and at four time points up to 255 days post-intervention using Prokopack aspiration. Generalized linear mixed models with a negative binomial link were used to estimate incidence rate ratios (IRRs) and calculate efficacy (1-IRR) for houses that received TIRS (direct effect) and untreated houses in TIRS clusters (indirect effect). Direct efficacy reached 96% at 15 days post-spraying and remained significant (40%) at 255 days post-spraying. Indirect efficacy reached 69% at 15 days and declined to 7% by 255 days post-spraying. Despite only 57% household-level TIRS coverage, both direct and indirect impacts on Ae. aegypti were significant during early post-intervention surveys, and after 8 months in TIRS clusters. Conclusions/SignificanceTIRS provided substantial and sustained reductions in indoor Ae. aegypti density, including measurable indirect effects in untreated homes within intervention clusters. These findings demonstrate the entomological value of TIRS even at moderate coverage levels and highlight its potential for both preventive and reactive vector control programs and should be considered for implementation by Ministries of Health in dengue-endemic urban settings as well as by the U.S. military when deployed to tropical or subtropical locations.

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Implementation Adherence and Operational Challenges of Rectal Artesunate for Severe Malaria in Zambia: A Mixed-Methods Study

Andrada, A.; Chanda, E.; Smith, I.; Sam, O.; Kyomuhangi, I.; Miller, J. M.; Silumbe, K.; Green, C.; Rietveld, H.; Bwalya, S.; Hamainza, B.; Chiwaula, J.; Webster, J.; Ye, Y.; Silvestre, E.; Ashton, R. A.; Eisele, T. P.

2026-05-22 public and global health 10.64898/2026.05.20.26353691 medRxiv
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Rectal artesunate (RAS) is a pre-referral intervention recommended for children with suspected severe malaria in remote settings where injectable treatment is not readily available. Although clinical trials have demonstrated efficacy, less is known about the behavioural and health system factors influencing effectiveness under routine conditions. A convergent parallel mixed-methods design was used to assess implementation of Zambia's RAS intervention package across three districts: Serenje, Chama, and Mwinilunga. A retrospective case-tracking investigation of all 300 children with suspected severe malaria recorded by community health workers (CHWs) assigned to study facilities examined progression and attrition across the severe malaria care cascade. In-depth interviews and focus group discussions with caregivers, CHWs, and other stakeholders explored barriers and facilitators influencing progression. Among 300 enrolled children, early attrition occurred due to negative rapid diagnostic test results. Of 239 RDT-positive children, 218 (91.2%) received RAS. Referral completion was lower; among 261 children referred and followed up at health facilities, 209 (80.1%) were confirmed to have completed referral. Of 186 children diagnosed with severe malaria at the facility, 167 (89.8%) received both injectable artesunate and follow-on artemether-lumefantrine. Patterns of disengagement varied by district, with Serenje demonstrating the most consistent progression, Chama experiencing the largest drop-off at RAS administration, and Mwinilunga showing the lowest completion of follow-on treatment. Qualitative findings revealed strong community appreciation for RAS despite stockouts, alongside social and behavioural barriers, including gendered responsibilities, transport challenges, and confusion following symptom improvement, that discouraged referral completion. RAS can be a life-saving intervention when embedded within strong health systems and community structures. Zambia's experience underscores the need for comprehensive implementation strategies that extend beyond drug distribution to include sustained CHW training, reliable commodity supply, functional referral systems, and meaningful caregiver engagement.

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High Incidence of Adverse Pregnancy Outcomes are Associated with Maternal Age and Infection Status in a Resource-Limited Community

Kituyi, S. N.; Odongo, A. O.; Wachuka, R.; Wambua, S.; Kobia, F.; Gitaka, J.; Kanoi, B. N.

2026-06-01 epidemiology 10.64898/2026.05.29.26354424 medRxiv
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Maternal health during pregnancy is critical for favorable birth outcomes and long-term wellbeing of both mothers and infants. Women in rural, malaria-endemic regions face unique biological and socioeconomic challenges that may increase the risk of adverse pregnancy outcomes (APOs). This study investigated the incidence and determinants of APOs among pregnant women attending antenatal care at Webuye sub-County Hospital in Western Kenya, a rural malaria-endemic setting. We conducted a retrospective cohort analysis utilizing previously collected data of 300 women enrolled during early pregnancy and followed through delivery. Maternal demographic, clinical, and infection-related factors were assessed, and associations with APOs were evaluated using chi-square tests and multivariable logistic regression. Maternal age and gestational age at enrollment were significantly associated with malaria history (P<0.001). Maternal BMI abnormality (124.5/1000 pregnancies), anemia (99.3/1000), fetal or neonatal death (81.3/1000), and preterm birth (43.8/1000) were observed (all P<0.001), suggesting a substantial burden. Younger mothers (<20 years) and older mothers (>35 years) were significantly more likely to develop anemia (P =0.026), and prior malaria infection further increased anemia risk (P =0.02). Abnormal urinalysis findings indicative of urinary tract infection were significantly associated with low birthweight (P =0.031). No significant associations were found between APOs and infant sex, parity, gravidity, or maternal ABO blood type. These findings highlight a substantial burden of APOs in this rural population, exceeding national and global estimates. Strengthening malaria prevention, nutritional support, urinary infection screening, and encouraging early antenatal care attendance are critical to improving maternal and neonatal outcomes. Targeted interventions for adolescent and older mothers, along with enhanced point-of-care diagnostics, may reduce preventable complications in similar resource-limited, malaria-endemic settings.

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A mixed-methods assessment of malaria case investigations and response in the elimination setting of Southern Province, Zambia

Karabo, R.; Kalyalya, S. M.; Miller, J.; Silumbe, K.; Hamainza, B.; Lungu, C.; Chanda, J.; Bennett, A.; Guinovart, C.; Mao, Z.; Ashton, R. A.; Stolow, J. A.; Eisele, T. P.

2026-05-26 public and global health 10.64898/2026.05.23.26353921 medRxiv
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Background In 2017, Zambia adopted surveillance as a core intervention towards achieving malaria elimination. Among the surveillance strategies is the malaria case investigation and response 1-3-7 (MCIR 1-3-7), which has been piloted in two low-incidence districts in the Southern Province since 2021. The study aimed to assess the implementation of MCIR 1-3-7 under programmatic conditions. It examined the timeliness, and completeness of the MCIR 1-3-7 activities, including the completeness of data entry in surveillance forms, and explored the experiences and perspectives of healthcare workers involved in the pilot. Methods A mixed-methods design was employed to assess the MCIR 1-3-7. Using a descriptive cross-sectional design, quantitative data were collected from 19 healthcare facilities in the two districts to assess the timeliness and completeness of MCIR 1-3-7. Additionally, 12 qualitative interviews were conducted with 29 healthcare workers from 11 of the 19 healthcare facilities. The interviews were voice-recorded and then transcribed manually. A codebook was developed using an iterative process to explore the facilitators and barriers encountered by healthcare workers in implementing the MCIR 1-3-7 intervention. All the visited facilities were purposively selected based on logistical convenience. Results This study retrospectively assessed 510 malaria cases that were diagnosed between January 2022 and June 2023, presenting at 19 health facilities: 283 cases in Chikankata and 227 in Mazabuka districts. A total of 278 cases (54.5%) were deemed to have been imported from outside the district, province, or country, while 45.5% (232/510) of the cases were classified as transmitted locally. Overall, 29.6% of case notification forms were found to be complete. Twelve interviews with 29 healthcare workers revealed a lack of transportation modalities as the main obstacle in executing the MCIR 1-3-7 intervention. The healthcare workers also indicated that monetary incentives, and supportive supervision would help them succeed in implementing this intervention. Conclusions The MCIR 1-3-7 has the potential to accelerate elimination in areas with low-transmission of malaria in Zambia. This study highlights opportunities to improve future implementation of the MCIR 1-3-7 intervention via strengthening supportive supervision, availing job aids, and ensuring access to malaria commodities as the intervention expands.

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Dengue spatiotemporal patterns in Minas Gerais, Brazil, 2014-2023: regional epidemic forces dominate over the environmental impact of the Brumadinho dam collapse

Fernandes, G. d. R.; Vaz, A. B. M.; Fonseca, P. L. C.; Oliveira, W. K.; Aguiar, E. R. G. R.; Lopes, B. C.; Mota-Filho, C. R.; Castro, M. L. P.; Starling, C. E.

2026-05-26 epidemiology 10.64898/2026.05.19.26353615 medRxiv
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Background: Dengue is a major public health problem in Brazil, and Minas Gerais is one of the states with the highest burden. In January 2019, the Brumadinho dam collapse released about 12 million cubic meters of iron ore tailings into the Paraopeba River basin, causing environmental disturbance that could plausibly affect vector habitats and dengue transmission. We evaluated the spatiotemporal dynamics of dengue in Minas Gerais from 2014 to 2023 and tested whether the disaster was associated with changes in affected municipalities. Methods: We performed an ecological spatiotemporal analysis using dengue notifications from SINAN for all municipalities in Minas Gerais (2014-2023). Municipalities were classified as Paraopeba basin, regional controls, or state controls. Temporal similarity was assessed using Pearson correlation-based hierarchical clustering and non-metric multidimensional scaling (NMDS). Sources of variation were examined with PERMANOVA and principal component analysis (PCA). A linear mixed-effects model with municipality as a random effect was used to test changes after 2019, with pre/post contrasts estimated from marginal means. Results: Dengue showed strong temporal synchrony across the state, with major epidemic peaks in 2015-2016, 2019, and 2023. Health region explained 31.5% of the variation in temporal incidence profiles (p = 0.001), whereas Paraopeba basin status explained no significant variation (p = 0.998). No temporal cluster was enriched for municipalities in the Paraopeba basin. PCA identified 2023, 2019, and 2016 as the main years driving variability. In the mixed model, year was significant (p < 0.001), but Paraopeba basin status and its interaction with time were not. Incidence increased significantly after 2019 in non-exposed municipalities (p < 0.001), but not in basin municipalities (p = 0.088). Conclusions: Dengue dynamics in Minas Gerais were driven mainly by regional and state-wide epidemic processes, with no significant independent effect of the Brumadinho dam collapse on notified dengue patterns.

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Comparison of the Mini Parasep SF, ParaPak SpinCon, and Paradevice fecal filtration and concentration devices for microscopic and AI-assisted detection of intestinal parasites

Morris, H.; Pritt, B. S.

2026-06-04 infectious diseases 10.64898/2026.06.02.26354769 medRxiv
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Effective filtration and concentration of stool specimens is an essential pre-analytical step for reducing fecal debris and improving organism recovery using microscopy-based ova and parasite (O&P) examination. This study evaluated three commercially available fecal sedimentation-based filtration/concentration systems, ParaPak SpinCon (Meridian Bioscience), Mini Parasep SF (Apacor), and the newly-available ParadeviceReingenuity), for qualitative parasite detection and workflow logistics using conventional and artificial intelligence (AI)-assisted microscopy. Forty clinical stool specimens (20 parasite-positive and 20 parasite-negative) were processed with the 3 devices, and the resultant 120 wet mount and 120 trichrome stained smear preparations were examined using conventional microscopy. Trichrome-stained slides were also scanned at 40x magnification using a Hamamatsu NanoZoomerS360 flatbed digital slide scanner and images were analyzed using the Techcyte Fusion Human Fecal Trichrome AI algorithm. Positive and indeterminate digital findings were confirmed by conventional glass slide microscopy. Slides and digital images were reviewed in a blinded manner. Concordance was assessed among the 360 initial evaluations (microscopy and AI-assisted), and discrepant parasitology results were resolved through re-review and specimen reprocessing as needed. Final qualitative agreement across slide/image evaluations using all three concentration systems was 100%. Minor discrepancies in protozoan and white/red blood cell detection/identification were noted in 5 and 7 cases, respectively, and likely reflected sampling and observer variability. While the three concentration systems produced equivalent qualitative results, the Paradevice and Mini Parasep SF offered the most streamlined workflows. These findings support the Paradevice and Mini Parasep SF as efficient, analytically equivalent systems that are compatible with traditional and AI-assisted O&P workflows.

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Suspected rabies exposure among animal-bite human cases in Busia district, Uganda: Prevalence, associated factors and delayed post-exposure care-seeking. A cross-sectional study

Wagaba, D.; Nabukenya, I.; Kizza, J.; Unith, H.; Kanyange, A.; Turyahabwe, C.; Kibuuka, H.; Mugisha, D.; Ogola, S. P.; Nabidda, S.; Kisakye, L. K.; Kalyango, J.

2026-06-01 epidemiology 10.64898/2026.05.29.26354408 medRxiv
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Background Rabies is a zoonotic neglected public health problem associated with animal bites, especially domestic carnivores claiming 59,000 deaths annually predominantly in developing countries of Africa and Asia. There is a high risk of exposure among rural communities endemic with animal rabies where adoption of prevention strategies is minimal. This study determined the prevalence of suspected rabies exposure, associated factors, and delayed post-exposure care-seeking among animal-bite human cases in Busia district, Uganda. Methods: This was a cross-sectional study that involved 332 consecutively sampled animal bite human cases that occurred within the period 2023 to 2024. Data for the bite cases from records were collected using a data abstraction tool. In addition, interviewer-administered semi-structured questionnaires were used to collect data on sociodemographic, animal-related and environmental characteristics. Approximate bite locations were collected using Global Positioning System (GPS) coordinates via Kobo collect. Analysis was carried out in STATA 17 using mixed effects modified Poisson regression for factors associated with suspected rabies exposure. Results: The median age of the bite cases was 18 (IQR: 9-36) with the male gender predominantly affected. The prevalence of suspected rabies exposure was 53.6% (95% Confidence interval - CI: 46.8-60.3). Factors associated were urban versus (vs) rural residence (adjusted prevalence ratio-aPR: 1.04, 95%CI: 1.00-1.08), being bitten by a stray animal (aPR: 1.28, 95% CI: 1.22-1.35) and wild animal (aPR: 1.22, 95% CI: 1.14-1.30) vs domestic animal, vaccination status of the biting animal i.e. vaccinated vs unvaccinated (aPR: 0.76, 95% CI: 0.69-0.85), provoked vs unprovoked bites (aPR: 0.82, 95% CI: 0.79-0.86), and distance to nearest river ([&ge;]5km) vs <5km (aPR: 0.93, 95% CI: 0.87-0.99). The prevalence of delayed post-exposure seeking was 23.0% (95% CI: 16.5-31.1) among the suspected rabies exposures. Conclusion: The study reveals a high prevalence of suspected rabies exposure. Factors associated are multidimensional i.e. are of human, animal and environmental origin. The one health paradigm should be emphasized during routine surveillance of rabies-related cases. The study observed that 1 in 5 bite cases delayed to seek care post bite exposure. We recommend collaborations between sectors, routine vaccination and awareness campaigns, and monitoring of wild carnivore populations and environmental dynamics in rabies-related surveillance.

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Translation and Cross-cultural Validation of Leprosy Case Detection Delay Questionnaire Among Persons Affected by Leprosy in Southeast Nigeria

Eze, C. C.; Murphy-Okpala, N. N.; Ekeke, N.; Nwafor, C.; Egbule, D.; Njoku, M.; Ezeakile, O.; Meka, A.; Iyama, F. S.; Ogbuefi, E.; Ugwu, O.; Solomon, M.; Adesigbin, C.; Chukwu, J.

2026-06-09 public and global health 10.64898/2026.06.06.26355058 medRxiv
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Introduction Reducing delays in leprosy case detection is essential for achieving global leprosy targets. Accurate measurement of these delays and their determinants relies largely on patient-reported data, as routine health records are often inadequate. The leprosy case detection delay (CDD) questionnaire, developed under the Post Exposure Prophylaxis for Leprosy (PEP4LEP) project, has been validated in Ethiopia, Mozambique, Tanzania, and Indonesia. However, it has not been adapted or validated for Nigeria or any major Nigerian indigenous language. This study aimed to culturally adapt and validate the CDD questionnaire for Igbo-speaking populations in Nigeria. Methodology/Principal Findings The CDD questionnaire underwent a standardized cross-cultural adaptation process. Content validity was assessed using item- and scale-level content validity indices, while construct validity was evaluated through hypothesis testing. Reproducibility was assessed using test-retest and inter-rater reliability; agreement using the Bland-Altman method and the Wilcoxon Signed-Rank test; reliability using Spearmans rank correlation coefficient and the Intraclass Correlation Coefficient (ICC); and internal consistency using Cronbachs alpha. Data were collected through face-to-face interviews with persons affected by leprosy at two time points separated by at least two weeks. Participants (n=100) had a mean age of 45.1 years (SD=18.7). Mean CDD was 77.2 months at baseline and 77.9 months at retest. The instrument demonstrated excellent content validity (I-CVI/S-CVI: 0.90-1.00), good internal consistency (Cronbachs =0.77), and excellent test-retest reliability (ICC=0.996, 95% CI: 0.994-0.997). Test and retest measurements were highly correlated ({rho}=0.985, p<0.001), with no evidence of systematic change over time (p=0.864). Seventy-two percent of participants reported identical CDD values across assessments. All items from the original English version were retained without modification. Conclusion/Significance The Igbo version of the CDD questionnaire demonstrated good validity and reliability and is suitable for assessing leprosy case detection delay among Igbo-speaking populations in Nigeria

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Bartonella and hemotropic Mycoplasma species in synanthropic bats in Kenya

DeAnglis, I. K.; Lunn, T. J.; Jackson, R. T.; Cummings, C. A.; Gates, E. C.; Griffey, B.; Mwakachola, B.; Mwasi, P.; Ogola, J. G.; Webala, P. W.; Sironen, T.; Becker, D. J.; Forbes, K. M.

2026-05-30 ecology 10.64898/2026.05.28.728508 medRxiv
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Identifying and characterizing zoonotic pathogens in wildlife is essential for understanding disease risk to humans. In Sub-Saharan Africa, many people live with bats in their houses and are exposed to their pathogens, yet little is known about the bacterial pathogens in Afrotropical bat species. Globally, Bartonella spp. (bartonellae) and hemotropic Mycoplasma spp. (hemoplasmas) are common bacterial pathogens in bats, and some lineages are known to spill over and cause infections in humans. To evaluate this disease risk, we screened three common synanthropic bat species in Kenya, and their ectoparasites, for hemoplasmas and bartonellae and assessed their relatedness to known human pathogens. Of 767 bats across 21 sites, 17.9% of bats were Bartonella spp. positive and 19.3% were hemoplasma positive. Bat ectoparasites had similar Bartonella prevalence (13.5-25.0%) and, for most bat species, ectoparasite loads were not associated with increased likelihood of Bartonella infection. We found that Bartonella lineages displayed phylogenetic overlap between different bat species and ectoparasites, suggesting pathogen sharing between species, while hemoplasma lineages corresponded strictly to host taxonomy. Finally, we found that 16S rRNA sequences from one heart-nosed bat (Cardioderma cor) were 97.85% similar to a human-associated hemoplasma found previously in Schreibers bats (Miniopterus schreibersii) in Spain. We show that synanthropic bats host bacteria of potential public health concern, highlighting the need to investigate the emerging impacts of these pathogens on human health in Kenya and elsewhere in Sub-Saharan Africa.

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Assessment of the laboratory capacity for testing Sexual Transmitted Infections at 14 health facilities in Moshi Municipality, Tanzania

Mosha, V. V.; Samky, E.; Ngowi, G.; Msemwa, M.; Macha, D.; Mwita, W.; Maokola, W.; Lyimo, J.; Harrison, O. B.; Msuya, S. E.

2026-05-18 health systems and quality improvement 10.64898/2026.05.13.26353104 medRxiv
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The global occurrence of sexually transmitted infections (STIs) continues to rise, necessitating accurate diagnosis and treatment to curb their spread and associated complications. With the alarming increase in antimicrobial resistance (AMR) in Neisseria gonorrhoeae, effective STI management relies heavily on etiological diagnosis. The Tanzania National Standard for Medical Laboratories 2017 outlines recommended STI testing protocols based on facility levels, yet adherence to these guidelines and associated challenges remain poorly documented. This study describes the diagnostic capacity for different STIs in northern Tanzania. A cross-sectional study was conducted between May and July 2023, encompassing 14 laboratories across Moshi Municipal Council, Kilimanjaro region. The laboratories assessed were in five hospitals and nine health centres (HCs). Data regarding facility type and STI diagnostic capabilities were gathered through questionnaires administered during site visits and supplemented by observations. All five hospitals were equipped to conduct rapid diagnostic tests for HIV, syphilis, and wet preparation microscopy for Trichomonas vaginalis (TV). Only three hospitals had the capacity to perform culture and sensitivity testing using chocolate and blood agar medium, however none reported isolating Neisseria gonorrhoeae in the past year. Critical STI diagnostic tests including the Treponema pallidum particle agglutination assay (TPPA) and Treponema pallidum hemagglutination assay (TPHA) for the laboratory confirmation of syphilis, assays for Chlamydia trachomatis, Herpes Simplex virus -2, and Human papillomavirus (HPV) were absent across all five hospitals. Conversely, all health centers demonstrated proficiency in rapid treponemal tests for syphilis, together with rapid HIV test and TV testing, although one health center lacked the capacity for wet laboratory preparation for TV detection. Findings underscore a concerning lack of STI testing capacity within surveyed healthcare facilities, posing significant barriers to effective STI management and exacerbating the threat of AMR in Tanzania. In particular, the capacity for conventional microbiology culture was limited in most settings, severely compromising the ability to track and monitor AMR. Urgent investment in laboratory infrastructure and training is imperative to enhance STI diagnosis and treatment, ultimately curtailing transmission and mitigating the impact of AMR.

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Access, Affordability, and Quality of Medicines in Public Primary Health Facilities in Ghana: Implications for Rational Use of Medicines

Awalime, D. K.; Aryeetey, G. C.; Koduah, A.

2026-05-18 health systems and quality improvement 10.64898/2026.05.14.26353169 medRxiv
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Rational use of medicines (RUM) is a global health priority, yet significant challenges persist in low- and middle-income countries (LMICs), particularly around medicine access, affordability, and quality. While RUM studies often focus on prescribing practices, systemic barriers such as supply chain inefficiencies and pricing receive less attention. This study assessed three key health system components of RUM (availability, affordability, and quality of essential medicines) at two public primary health facilities in Ghana and examined patient care practices against WHO RUM standards. A quantitative, cross-sectional study was conducted at Kekele Polyclinic and Rawlings Circle Polyclinic in Accra. Retrospective data were extracted from prescription sheets, medicine tally cards, and ledgers to evaluate WHO Level II core drug use indicators. Fifteen essential medicines were selected based on the Ghana Essential Medicines List, Standard Treatment Guidelines, and municipal disease burden data. Exit interviews with 107 patients assessed dispensing and counselling practices, and structured observation covered storage conditions and pharmaceutical handling. Availability of key medicines fell significantly short of WHO targets, with Rawlings Circle meeting only 40% and Kekele 73.3% of the 100% benchmark. Treatment of malaria and pneumonia cost patients up to three times the national daily minimum wage, indicating poor affordability. The average number of medicines prescribed per encounter (3.2) exceeded the WHO recommended standard ([&le;]2). Storage and handling infrastructure was inadequate, with both facilities falling short of recommended conservation standards. Gaps in medicine availability, affordability, and infrastructure undermine rational medicine use in primary healthcare. Strengthening procurement systems, enforcing storage protocols, and implementing financial protection mechanisms are essential for equitable and safe medicine use within Ghanas health system.

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Usage Pattern and Associated Factors of Natural Mosquitoes Remedies in Endemic Communities of Borno State, Nigeria

Njapdze, R. K.; Ekerette, I. B.

2026-06-08 public and global health 10.64898/2026.06.04.25342216 medRxiv
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Introduction: Malaria, primarily transmitted by Anopheles mosquitoes, remains a major public health concern in Maiduguri, Borno State, Nigeria. While conventional control methods (e.g., ITNs) face challenges due to insecticide resistance and accessibility constraints, many communities rely on locally sourced natural products. This study aimed to assess the prevalence, usage patterns, and associated factors of these natural alternatives. Methods: A cross-sectional survey was conducted across three purposefully selected communities in Maiduguri (Mairi, Furi, Lagos Street). A total of 450 household heads were interviewed using a structured questionnaire, collecting data on socio-demographics, specific natural products used, method of application, frequency, and perceived efficacy. Data were analyzed using descriptive statistics and binary logistic regression. Results: Overall usage prevalence of natural products was high at 68.4%. The most common products identified were Neem (Azadirachta indica) extract (45.9%) and burnt Lemon Grass (Cymbopogon citratus) (31.2%). Usage pattern was predominantly indoor fumigation (burning), and over 70% of users prepared the products crudely at home. Logistic regression revealed that rural residence (Odds Ratio (OR): 2.1; p<0.01) and low education level (OR: 1.8; p<0.05) were significant independent predictors of higher natural product reliance. Conclusion: Natural products constitute a widely adopted, community-driven vector control method in Borno State. The high prevalence and association with vulnerable populations suggest an urgent need to standardize the preparation and application of these products for potential integration into regional malaria control programs. Keywords: Anopheles, Adulticides, Borno State, Malaria, Natural Repellents, Vector Control, Usage Pattern.

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Bayesian Spatio-Temporal Modeling and Hotspot Mapping of Malaria Risk in Ghana

Antwi, P.; Muhua, G.; Nyarko, E.

2026-05-22 epidemiology 10.64898/2026.05.19.26353586 medRxiv
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Purpose: This study developed a Bayesian hierarchical spatio-temporal modeling framework to analyze factors and trends in malaria risk across Ghana's 16 administrative regions from 2020 to 2024. The aim was to identify statistically significant areas with elevated or persistent malaria risk, to inform targeted intervention planning and support the National Malaria Elimination Program. Methods: This study utilized malaria incidence data from the Ghana Health Service's District Health Information Management System-II covering the years 2020 to 2024. Meteorological data were sourced from the Visual Crossing Weather Data, and regional population estimates were obtained from the Ghana Statistical Service. To analyze the data, a Bayesian hierarchical spatiotemporal model with a Negative Binomial (NB) likelihood was implemented using Integrated Nested Laplace Approximation to account for overdispersion. The model included Conditional Autoregressive priors for structured spatial effects, first-order random walk priors for temporal dependence, and spatio-temporal interaction terms. Additionally, Local Indicators of Spatial Association (LISA) analysis with 999 conditional permutations was conducted to identify statistically significant spatial clusters, including high-high hotspots and low-low cold spots. Results: The NB model significantly outperformed the Poisson model, leading to a reduction in the dispersion statistic from 9,227.55 to 1.11. Humidity with a 1-month lag showed the strongest positive association with malaria risk, while the ultraviolet index had the greatest protective effect. Predictive relative risk maps identified persistent high-risk clusters in the northern and northwestern regions, specifically Upper West, Upper East, Bono, Ahafo, and Western North. LISA analysis indicated that Bono-Ahafo has been a stable high-high cluster from 2020 to 2023, while Ashanti has remained a consistent low-high anomaly. Additionally, Greater Accra and Central regions formed a significant low-low cluster in 2024. Conclusion: The Bayesian hierarchical spatio-temporal framework effectively characterized the complex transmission dynamics of malaria in Ghana. It revealed significant spatial dependence, temporal correlation, and interactions between these factors. By identifying persistent high-risk clusters and statistically significant spatial associations, this framework provides essential evidence to guide resource allocation. These findings support Ghana's National Malaria Elimination Program Strategic Plan (2024-2028) by enabling targeted interventions in hotspots and optimizing the use of limited resources to sustain progress in low-transmission areas.

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Spatial and temporal associations between animal ownership and malaria prevalence in Africa using cross-sectional national Demographic and Health Surveys

Topazian, H. M.; Morgan, C. E.; Goel, V.

2026-06-08 epidemiology 10.64898/2026.06.05.26355017 medRxiv
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Use of zooprophylaxis as a malaria control strategy has been recommended historically, but a complex relationship exists between animal ownership and malaria infection, with mixed associations described in the literature. We sought to characterize this relationship spatially and temporally in malaria-endemic regions of Africa. We used data from 392,843 individuals from 66 Demographic and Health surveys from countries within Africa to investigate the association between household animal ownership and Plasmodium infection. We used Bayesian models with Integrated Nested Laplace Approximation to incorporate spatially varying coefficient processes, allowing the association of interest to vary over space, time, and within strata of vector species occurrence, land cover, and number of animals owned by households. Spatially varying intercept models showed that ownership of cattle, chickens/poultry, goats, horses/donkeys/mules, pigs, and sheep was broadly associated with malaria infection, with odds ratios ranging from 1.55 to 1.67. However, spatially varying slope models revealed considerable heterogeneity, with odds ratio estimates for all animal types demonstrating both protective and harmful effects varying from 0.33 to 3.33 both subnationally and across time. We found no evidence that modification by vector species, number of animals owned, and land cover fully explained the variation in estimates. Unobserved localized cultural, behavioral, or ecological factors likely modify the association between animal ownership and malaria prevalence. Further exploring the nature of this relationship over space and time will be important to understanding how context-specific One Health dynamics between humans, animals and the environment affect malaria prevention and control efforts.

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Bacteriological contamination of drinking water from source to point of consumption in Ivorian households: a nationwide analysis of the 2021 Demographic and Health Survey

KONAN, L. G.; Eugene, K. Y.; Tecthi, O.; Victoire, I.; Audrey, A.; Elvis, S. A. G. F.; Constant, K. K.; Jennifer, L. B. D.; Odile, A.-T.

2026-05-21 public and global health 10.64898/2026.05.18.26353533 medRxiv
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Background Bacteriological contamination of drinking water remains a major public health burden in sub-Saharan Africa, yet the full contamination chain from source to household has rarely been quantified at national scale. This study analyses water quality at both levels using the 2021 Cote d'Ivoire Demographic and Health Survey (DHS-CI 2021). Methods Cross-sectional secondary analysis of DHS-CI 2021 data. Households with paired bacteriological tests at the source (SH3227) and at the household (SH3225) were included (n = 2,541 for determinants; n = 2,528 for chain analysis). Contamination was defined as >0 CFU/100 ml. Determinants of source contamination were assessed by weighted logistic regression accounting for complex survey design. The contamination chain was described across four categories: safe throughout, recontaminated during transport/storage, decontaminated at home, and contaminated throughout. Results Weighted prevalence of source contamination was 63.6% [95% CI: 60.7-66.5%] and 77.0% [74.1-79.9%] at the household. Only 15.0% of households had safe water throughout the chain; 21.2% showed domestic recontamination and 60.8% consumed water contaminated at both levels. Key determinants of source contamination were use of an unimproved source (aOR = 8.15; 95% CI: 4.54-14.66), administrative region, travel time [&le;]30 minutes (aOR = 1.92; 95% CI: 1.41-2.62), and higher wealth quintiles (protective; aOR = 0.25 for richest). Model discrimination was good (AUC = 0.809). Conclusions The vast majority of Ivorian households consume bacteriologically unsafe water, with domestic recontamination representing a distinct and significant degradation pathway even among users of improved sources. Dual interventions targeting source protection and safe household water storage are urgently needed to advance progress toward SDG 6 in Cote d'Ivoire.

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Reduced fecal intestinal alkaline phosphatase is associated with gestational diabetes mellitus: A hospital-based multicentre cross-sectional study in Bangladesh

Chowdhury, P.; Tofail, T.; Akter, N.; Islam, H.; Bokshi, A.; Sultana, M.; Podder, S.; Malo, M. S.; Hasanat, M.

2026-05-19 endocrinology 10.64898/2026.05.14.26353231 medRxiv
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Gestational diabetes mellitus (GDM) is a major metabolic complication of pregnancy with significant maternal and fetal adverse consequences. Beyond classical mechanisms, emerging evidence suggests that gut-derived metabolic endotoxemia may contribute to dysglycemia. Intestinal alkaline phosphatase (IAP), a key enzyme involved in maintaining gut barrier integrity and detoxifying lipopolysaccharides, has been linked to type 2 diabetes mellitus; however, its role in GDM remains largely unexplored. This hospital-based cross-sectional analytical study evaluated fecal IAP levels and their association with GDM among 198 pregnant women recruited from three antenatal care clinics representing three tiers of ANC services. Participants were screened for GDM using a 75-g oral glucose tolerance test and classified as having GDM (n=55) or normal glucose tolerance (NGT; n=143) according to WHO 2013 criteria. Stool samples were collected, and fecal IAP levels were measured using an enzymatic colorimetric assay. Fecal IAP level was significantly lower in women with GDM than in those with NGT (median 23.59 vs 46.48 U/g stool; p<0.001). Lower IAP level remained independently associated with GDM after adjustment for body mass index and previous GDM (adjusted OR 0.98 per unit increase; 95% CI 0.97-0.99; p<0.001). A graded relationship was observed between declining IAP level and GDM. Receiver operating characteristic analysis demonstrated modest discrimination (AUC 0.676), while a threshold of approximately 65 U/g stool yielded high sensitivity (89.1%) but lower specificity. Reduced fecal IAP is independently associated with GDM, supporting a potential role of gut-derived metabolic dysregulation in gestational glucose intolerance. While not suitable as a standalone diagnostic tool, fecal IAP may serve as a complementary biomarker for risk stratification during pregnancy. Prospective studies are warranted to determine its predictive value and explore its potential as a therapeutic target.

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Effectiveness of Lifestyle Interventions for Glycemic Control among Adults with Type 2 Diabetes in West Africa: a Systematic Review and Meta-analysis.

Bondzie, E. P. K.; Adjei-Banuah, N. Y.; Afun, N. E. E.; Peprah, E. B.; Jahan, Y.; Mirzoev, T.; Balabanova, D.; Agyepong, I.

2026-05-22 endocrinology 10.64898/2026.05.16.26353078 medRxiv
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Type 2 Diabetes (T2D) is a growing public health burden in West Africa, yet the effectiveness of lifestyle interventions for glycemic control in this region remains unclear. This systematic review and meta-analysis evaluated the impact of lifestyle interventions on Fasting Blood Glucose (FBG) and Glycated Hemoglobin (HbA1c) levels among adults with T2D in West Africa. A systematic search of PubMed, Scopus, Africa Journals Online, and Cairn.info was conducted following PRISMA guidelines. Randomized controlled trials (RCTs) and quasi-experimental studies evaluating lifestyle interventions (physical activity, dietary modification, and combined/educational interventions) for glycemic control in adults with T2D in West Africa were included. Meta-analysis was performed via a random-effects model with restricted maximum likelihood (REML) estimation, using mean differences (MD) as the effect measure for both FBG and HbA1c outcomes. Heterogeneity was assessed via I2 statistics, and sensitivity, subgroup, and meta-regression analyses were conducted to examine potential moderators of the observed heterogeneity. Ten studies comprising 645 participants were included. Six studies reported FBG outcomes; however, two were excluded from the FBG meta-analysis due to missing control group post-test values and absence of a control group respectively, leaving four studies for pooling. A separate set of four studies contributed to the HbA1c meta-analysis. For FBG, lifestyle interventions were associated with reduction in FBG levels (pooled MD = -1.81 mmol/L, 95% CI: -2.33 to -1.30, p < 0.001), with moderate heterogeneity (I2 = 50.76%). The certainty of evidence assessed using the GRADE approach was rated as low for FBG outcomes and very low for HbA1c outcomes, reflecting concerns about imprecision and inconsistency across studies. Leave-one-out sensitivity analysis confirmed robustness of this finding, with estimates ranging from -1.707 to -2.087 mmol/L. Neither intervention duration nor sample size significantly moderated FBG effect sizes, with the model explaining approximately 15.7% of observed heterogeneity. For HbA1c, lifestyle interventions were also associated with reduction in HbA1c levels (pooled MD = -1.044%, 95% CI: -1.594 to -0.495, p = 0.0002), though heterogeneity was exceptionally high (I2 = 98.08%), limiting interpretability of the pooled estimate. Exploratory meta-regression identified intervention duration and sample size as statistically associated with HbA1c effect size, though the model was saturated given the small number of studies and findings should not be interpreted as confirmatory evidence of moderation. Conclusion: Lifestyle interventions, including supervised physical activity, dietary modification, and community-based diabetes education, were generally associated with improvements in glycemic control among adults with type 2 diabetes in West Africa. Evidence was more consistent for fasting blood glucose, while findings for HbA1c were highly heterogeneous and should be interpreted with caution. These results suggest potential benefit, but variability across studies highlights the need for more standardized and rigorously designed trials in the region.

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Estimating the impact of different intermittent preventative treatment in pregnancy delivery strategies on low birth weight outcomes under moderate and high malaria transmission setting: A modelling study

Chakuvinga, L.; Franco, C.; Silal, S.

2026-06-02 public and global health 10.64898/2026.05.30.26354497 medRxiv
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Introduction: Malaria during pregnancy is a major risk factor for low birth weight (LBW) in newborns, which in turn negatively affects the growth and development of the child. The World Health Organization (WHO) recommended interventions for pregnant women living in malaria endemic countries that include the use of intermittent preventive treatment in pregnancy (IPTp). However, WHO asserts that the coverage of pregnant women taking the recommended doses of IPTp are still very low. The primary goal of this study was to estimate the effects of increasing the coverage of doses of IPTp and to assess the effect of pregnancy timing in relation to seasonal transmission on malaria infections during pregnancy and neonates with LBW. We explored these effects in moderate and high transmission settings. Methods and Findings: A compartmental mathematical model depicting malaria during pregnancy with IPTp doses was formulated to analyze the effects of IPTp, insecticide treated net (ITN) use and seasonal variations in moderate and high malaria transmission settings. Our simulation findings suggest that increasing both ITN use and IPTp dose coverages to high levels, prevents 90% and 84% clinical cases for pregnancies starting in August in moderate and high transmission, respectively. Our model predicts that increasing the coverage of the first dose of IPTp to 90%, while lowering subsequent doses, averts 44% and 37% LBW cases for the August cohort in moderate and high transmission settings, respectively. Unprotected pregnancies overlapping the January peak in rainfall and malaria incidence during the third trimester experience the highest LBW burden. Conclusions: The highest IPTp coverage prevents the highest number of LBWs providing evidence of the benefits of scaling up IPTp. Overall, our results demonstrate that increasing ITN use has a substantial impact in reducing clinical malaria cases during pregnancy and improves birth outcomes. This highlights its importance as a key intervention, and the health benefits it would provide for malaria control goals for pregnant women. Pregnancies that overlap with the epidemic peaks in later trimesters lead to a rise in LBWs, indicating the necessity of protecting pregnant women at risk of malaria infection till delivery.

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Emerging combinations of climatic parameters for dengue proliferation in urban landscapes

Vaishya, A.; Patel, V.; Dahima, Y.; Chowdhury, L. S.; Jana, K.; Adhvaryu, B.; Mahadevia, D.; Shah, C.; Rajpurohit, S.

2026-05-21 ecology 10.64898/2026.05.19.726173 medRxiv
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Ectotherm insects growth and development are dictated by temperature and humidity. Conducive habitats and the availability of resources set ideal conditions for insect population growth. Mosquitoes require water, favorable temperature, and blood meal to survive. In this research, we picked a rapidly growing megacity, Ahmedabad, in western India, to explore and establish potential linkages between disease spread and meteorological conditions. Ahmedabad, with a population of over 8 million, is experiencing changes in rain and humidity patterns, pushing the city towards changing vector-borne disease dynamics. We examined dengue cases over ten years, 2012-22, and explored their connections with two prominent climatic variables, temperature and relative humidity. Our findings indicate that stable temperature (25-27.5 {degrees}C) and humidity (> 60%) interaction is a ruling factor in spikes in dengue cases in the city. While stable temperature ranges triggers the dengue cases, RH drives the explosive phases and sustainability of such episodes. Statistically significant increasing trends in temperatures, narrowing down of the day-night temperature ranges, and increasing night temperatures provide more stable temperature regimes in a warming world thereby likely to extend the dengue season beyond the usual monsoon season. Plain Language SummaryDengue incidences have been found to be associated with mosquito population outbreaks. Every year, thousands of lives are lost due to this deadly virus spread by mosquitoes. Particularly in the Indian subcontinent, a large proportion of these cases is associated with the monsoon season and rain patterns. In recent years, there have been abrupt spikes in dengue cases across Indian cities, particularly in western India. To understand this complex interaction of viral proliferation and local environmental conditions, the last ten years of dengue case patterns have been scanned in parallel to the climate data. Our findings suggest that stable temperature windows and humidity levels above certain thresholds trigger a rise in dengue cases. While stable temperature ranges trigger dengue cases, humidity drives such episodes explosive phases and sustainability. Our work pinpoints specific temperature-humidity combinations and suggests that local municipal corporations use them as warning indicators to initiate preventive measures.