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Acta Tropica

○ Elsevier BV

Preprints posted in the last 30 days, ranked by how well they match Acta Tropica's content profile, based on 13 papers previously published here. The average preprint has a 0.02% match score for this journal, so anything above that is already an above-average fit.

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Prevalence of malaria among pregnant women attending ANC at public health institutions in Damote-Gale district, Southern Ethiopia

Kussa, Y.; Lema, S.

2026-09-23 public and global health 10.64898/2026.09.21.26363605 medRxiv
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BackgroundIn Ethiopia as other Sub-Sharan African countries malaria in pregnancy is a major public health threat particularly in the rural communities. Immunosuppression during pregnancy increases the risk of placental malaria; this, in turn, leads to anemia, low birth weight, preterm delivery, and stillbirth, causing severe complications that pose a life-threatening risk to both the mother and fetus. Hence, this study is aimed to assess the prevalence of malaria, and associated factors among pregnant women attending antenatal clinics in Damot Gale district, South Ethiopia. MethodAn institutional-based cross sectional study was conducted from March 1 to May 30, 2024. A multistage sampling technique and pre-tested semi-structured questionnaires were used for data collection. Using standard parasitological methods, blood samples collected from 389 participants were analyzed through microscopic examination of Giemsa-stained thick and thin blood films. Logistic regression was used to assess factors associated with malaria. Adjusted odds ratio with 95% confidence interval was calculated and P-value < 0.05 was considered statistically significant. ResultsIn this study the prevalence of malaria among pregnant women was 10.5% (95% CI: 7.7-13.6%). Among the malaria-positive pregnant women (9%) were P. falciparum infected, followed by P. vivax (1.3) and mixed infections (0.2%). In the multivariate analysis, multigravdae (AOR = 0.358; 95% CI: 0.14-0.92), utilization of LLINs (AOR = 0.286; 95% CI: 0.119-0.687) and use of IRS (AOR = 0.068; 95% CI: 0.027-0.172) were significantly associated with malaria among pregnant women. ConclusionMalaria is still a public health problem among pregnant women in Damote-gale district. The present study indicated that adequate distribution and proper utilization of bed nets In addition seasonal proper spray of IRS might be helpful to prevent and control malaria.

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First confirmed record in Melilla of Gerbillus campestris Loche, 1867 (Muridae: Gerbillinae) for Spain

Ferrandez Verdu, T.; Ruiz, F. P.; Carrillo Lopez, A. F.; Tapia Caro, M.; Castillo Gonzalez, A.; Vives Lopez, R.; Amoros Box, C.; Marcos Perez, M.; Boratynski, Z.; Pavlickova, B.

2026-10-06 zoology 10.64898/2026.09.30.754369 medRxiv
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The fieldwork was carried out between December 2023 and June 2025, with the aim, among others, of confirming the possible presence of the North African Gerbil (Gerbillus campestris) in Melilla. To this end, 56 camera trap stations were installed, each equipped with a camera trap. Of the total number of camera trap stations installed, the presence of Gerbillus campestris was detected in six of them, representing a capture success rate of 10.71%. Following the detection of the species, a specimen was captured using cage traps. For identification purposes, samples of epithelial tissue from the ear and faeces were collected. These samples were sent to the Institute of Vertebrate Biology of the Czech Academy of Sciences, Brno, Czech Republic, for analysis. There, DNA was extracted from the samples using the Innu PREP DNA Mini Kit 2.0 (IST Innuscreen GmbH, Germany) according to the manufacturer's protocol. The results obtained confirm, for the first time through records of the species, the presence of Gerbillus campestris in Melilla and, therefore, in Spain and Europe.

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Insecticide resistance of Culex pipiens f. pipiens is geographically widespread in Germany and displays an unmatched genotypic and phenotypic resistance state

Vandenberghe, E.; Vereecken, S.; Reuss, F.; Brusius, I.; Janssens, C.; Magdeburg, A.; Groneberg, D. A.; Muller, R.; Kramer, I. M.

2026-09-24 molecular biology 10.64898/2026.09.23.753539 medRxiv
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In Germany, insecticide use is recommended during mosquito-borne disease outbreaks, yet nationwide data on insecticide resistance in key vector species are scarce. This is particularly relevant for Culex pipiens s.l., a vector of West Nile virus. Here, we provide the first broad-scale assessment of molecular insecticide resistance (kdr and ace-1 mutations) in Cx. pipiens f. pipiens across Germany. We associated insecticide resistances with environmental conditions, potential links with mitochondrial variation of the cytochrome c oxidase I (COI) gene as well as phenotypic resistance (CDC bottle assay with permethrin) of the Frankfurt population with elevated kdr frequencies. Kdr resistance alleles were detected in German Cx. pipiens f. pipiens reaching frequencies of up to 50% in the metropolitan areas of Berlin and Frankfurt am Main. Annual precipitation was negatively associated with kdr allele frequency. Interestingly, ace-1 resistance mutations were only present in the metropolitan area of Frankfurt am Main and in Muggensturm (Rhine valley, southwestern Germany). COI haplotype analyses revealed low genetic variability within German Cx. pipiens f. pipiens populations with no association to the insecticide resistance genotype. Phenotypic assays of the Frankfurt population showed early signs of permethrin resistance, but unmatched genotypic and phenotypic resistance state. This study provides the first broad-scale assessment of molecular insecticide resistance in Cx. pipiens f. pipiens across Germany, establishing a baseline for resistance surveillance and vector control. Further research is needed to identify factors shaping phenotypic resistance, as molecular markers alone may not reliably predict resistance. Since sampling was restricted to urban green spaces, broader sampling across environmental gradients is needed to identify additional environmental effectors.

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Population genetic structure and connectivity of Glossina palpalis gambiensis and G. morsitans submorsitans in Southwestern Senegal

Bakhoum, M. T.; Fall, A. G.; Segard, A.; Seck, M. T.; Thiall, A. S.; Gimonneau, G.; Ravel, S.; DE MEEUS, T.

2026-09-24 ecology 10.64898/2026.09.24.753986 medRxiv
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In sub-Saharan Africa, human and animal health is threatened by African trypanosomoses. These diseases are caused by trypanosomes that are transmitted primarily by tsetse flies. Vector control remains one of the most effective strategies for reducing disease transmission, but requires a minimum level of knowledge of the population biology, ecology and dispersal patterns of the targeted vectors. In this respect, population genetic approaches using appropriate polymorphic genetic markers can provide valuable tools to inform and optimize control strategies. Senegal is currently engaged in a national tsetse control programme and has been identified as a study country within a European Union-funded research initiative, COMBAT (controlling and progressively minimizing the burden of animal trypanosomosis). Baseline entomological studies are currently underway in the Sine Saloum (Southern Senegal). This preliminary study aimed to characterize the population genetic structure and connectivity of tsetse fly species present in Southern Senegal, Glossina palpalis gambiensis and G. morsitans submorsitans, in order to assess their population sizes (geographically and demographically), population densities and dispersal capacities. The two species exhibited markedly contrasting population structures. The first, G. p. gambiensis, displayed an isolation by distance with rather dense subpopulations exchanging immigrants at short distances (1.6 km/generation) and continuously from Sine-Saloum to Casamance, in line with the apparent continuity of the mangrove network found along this coast. In contrast, G. m. submorsitans presented a relatively dense population over a 75 km wide area, fragmented into sparsely distributed, very dense and interconnected pockets. These findings indicate that G. p. gambiensis likely constitutes a large metapopulation comprising 3266 effective individuals on average (and up to 7765), whereas G. m. submorsitans appeared as a single and large population, scattered in small pockets that could be readily replenished by immigrants from distant areas in case of control. These results suggest that elimination is not a realistic option for any of these two populations. Alternatively, localized integrated pest management is likely to be the most effective approach for controlling the negative effects of these biting flies on domestic animals, by reducing trypanosome transmission. However, further entomological investigations and the use of more informative genetic markers are needed to obtain a more precise understanding of the epidemiological processes involved.

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Increased sensitivity of detecting variation in malaria endemicity by parasite density measurement in large surveys

Oyibo, W.; Blair, A. M.; Oladipo, O.; Ogbulafor, N.; Urude, R. O.; Onwuachusi, G.; Anabike, C.; Ntadom, G.; Okoronkwo, C.; Uhomoibhi, P.; Eze, N.; Oresanya, O.; Mahmoud, A.; Okoro, O.; Aduagba, B.; Ijezie, S.; Okoh, F.; Kawu, I.; Ozor, L.; Maikore, I.; Maxwell, K.; Ezeiru, S.; Nwokolo, E.; Amajoh, C.; Audu, M.; Mokuolu, O.; Biyama, Z.; Adeyoju, T.; Obike, N.; Ilelaboye, J.; Lawson, A.; Conway, D. J.

2026-10-08 infectious diseases 10.64898/2026.10.07.26364850 medRxiv
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Introduction: The continuing high and inequitable global malaria burden requires improved methods to understand trends and target control. Current methods often involve infection prevalence surveys, but additional parasitological measures could increase precision in estimating infection burdens of communities. Methods: Focusing on the country with most malaria globally, examinations of slides from 10,651 children under five sampled in the 2021 national Malaria Indicator Survey in Nigeria were performed to measure asexual parasite densities in infected children and discriminate sexual stages and species. Variation in these indices among the six different geopolitical zones and 37 individual states including the Federal Capital Territory were compared with the variation indicated by infection prevalence alone. Results: Among the six major geopolitical zones, only one had significantly higher asexual parasite prevalence than others, but parasite densities within infected children revealed more significant variation among the different zones. Comparing results for 2021 with previous data from 2018, one zone showed lower asexual parasite prevalence and two had lower sexual parasite prevalence, but three had higher asexual parasite densities in infected children. Variation in parasite densities among individual states also highlighted significant geographical and temporal differences, extending the detection of heterogeneity within each geopolitical zone. Overall trends were driven by the predominant parasite species Plasmodium falciparum as prevalence and density of the other species were much lower. Conclusions: Findings indicate that understanding complex patterns of geographical and temporal variation is enhanced by including asexual parasite density measurement, providing opportunities for more precise targeting of malaria control within high burden countries.

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First nationwide mosquito surveillance in Northern Irish wetlands reveals presence of Culex pipiens/molestus hybrids

Carmichael, R. M.; Kirby, G.; Sloan, L.; Desjardins, A.; Parvy, J.-P.; Baldini, F.; Pondeville, E.; Dick, J. T. A.; Ferguson, H. M.; Cuthbert, R. N.

2026-10-09 ecology 10.64898/2026.10.08.757519 medRxiv
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While mosquito invasions and associated pathogens are increasingly prominent in Europe, evidence gaps remain for many northerly regions where proactive management interventions may be most effective. At the regional periphery of Europe, there remains a significant knowledge gap concerning mosquito vector distributions in Northern Ireland. This study aimed to address this major gap by systematically surveying larval and adult mosquito populations in key habitats (ponds, reedbeds, saltmarsh, wet grasslands, wet woodlands, and urban gardens). We further identified environmental drivers of important vector species abundance and screened collected specimens with molecular techniques to identify presence of cryptic human-biting vector species. In Northern Ireland, mosquitoes (including potential bridge vectors of West Nile and Usutu viruses) were found to be widely distributed. Between May and August 2025, a total of 2430 mosquitoes (951 adults and 1479 larvae) were collected over 196 trap nights and 76 larval collections. Collections encompassed 17 species, with Culex pipiens/torrentium being the most widely distributed and abundant taxon recorded. Mosquito abundances were greatest in reedbed habitats, related negatively with rainfall and peaked in June and July. A subset of Culex pipiens/torrentium mosquitoes were identified to species/biotype level using PCR, with the majority (89.3%) identified as Culex pipiens pipiens and 9.3% as Culex torrentium. Importantly, the first detections of Culex pipiens/molestus hybrids (1.8%) on the island of Ireland were found. This work underscores the wide, yet previously undocumented abundance and distribution of potential zoonotic vectors in Northern Ireland and provides an important baseline for management planning and future research, while contributing to broader understandings of environmental population drivers and distributions.

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Long-Term Surveillance Reveals Establishment of Aedes albopictus in Eastern Nebraska, USA

Coleman, G. A.; Hamik, J.; Smith, H.; Mucha, T.; Rault, L. C.; Anderson, T. D.

2026-09-28 ecology 10.64898/2026.09.23.750200 medRxiv
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Aedes albopictus (Skuse), the Asian tiger mosquito, is a highly competent arboviral vector whose range has expanded substantially across the United States over the past four decades. Despite predictive models placing Nebraska within the species' climatically suitable range, its establishment status in the state has remained poorly characterized. Here, we report results from a nine-year mosquito surveillance program (2017-2025) conducted across 44 Nebraska counties in collaboration with the Nebraska Department of Health and Human Services. Ae. albopictus was detected in five counties, with sustained, annually increasing populations documented in Richardson, Douglas, and Lancaster counties. Richardson County recorded continuous detections during 2017-2025, with proportional representation rising to 60.50% of collected mosquitoes by 2025. In Douglas and Lancaster counties, temporal advancement of first seasonal detection in 2024 and 2025 provide evidence consistent with successful overwintering rather than annual reintroduction. A cumulative degree-day model predicted adult emergence in mid-May across all county-year combinations, consistently preceding trap deployment by two to seven weeks and revealing a systematic early-season surveillance gap. Generalized linear mixed-effects models indicated that trap-level detection persistence, rather than urban location, was the primary predictor of yearly Ae. albopictus positivity, suggesting that current invasion dynamics are driven by focal source populations. These findings provide strong evidence for the establishment of Ae. albopictus in eastern Nebraska and highlight the need for earlier seasonal surveillance and standardized criteria to define establishment in northward-expanding vector populations.

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Factors Associated with Divergent Introgression Outcomes from Wolbachia-Based Interventions in Rio de Janeiro, Brazil

Nelson, E.; Carcamo, P. M.; Ribeiro dos Santos, G.; Sylvestre Ribeiro, G.; Rodrigues da Costa, T.; Ilaria Dorigatti, I.; Salje, H.; Moreira, L. A.; Cummings, D. A. T.; Ko, A. I.

2026-10-21 infectious diseases 10.64898/2026.10.16.26365711 medRxiv
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Wolbachia-based interventions were less effective in achieving introgression in Rio de Janeiro than other settings. Reduced introgression occurred in locations where dengue was historically high, raising concerns of inequity. We examined factors affecting Wolbachia introgression in Rio through trajectory modeling, spatiotemporal Bayesian models, and Ae. aegypti abundance estimation. During the intervention (2017-2020), Wolbachia introgression was 26% (median; IQR,14-44%), with four distinct trajectories. Despite receiving more releases, densely populated areas with low socioeconomic status had lower introgression. In spatiotemporally explicit multivariable regressions, higher Ae. aegypti abundance, temperature, population density and lower socioeconomic status were associated with reduced introgression. Improved characterization of Ae. aegypti abundance and other structural/environmental predictors of introgression could be used to calibrate release doses to ensure equitable benefits from Wolbachia interventions.

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Association between breeding-habitat bacterial communities and oviposition behavior of Aedes aegypti: Insights from arboviral outbreak-affected areas of Pune, Western India

Singh, S.; Raikar, M.; Dongardive, S.; Ramdasi, A.; Kumar, S.; Dhaigude, S.; Kadam, P.; Viswanathan, R.; Yadav, A.; Karmodiya, K.; Lole, K. S.; Banerjee, K.; PR, S.; De, T. D.

2026-10-02 genomics 10.64898/2026.10.01.755851 medRxiv
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Aedes aegypti, an important vector of several arboviral diseases, is highly adapted to human-associated environments and commonly exploits anthropogenic water-holding containers for breeding. Understanding the ecological factors governing oviposition-site selection is essential for developing sustainable vector control strategies. Previous studies have established that microbial communities in breeding waters influence mosquito oviposition-site selection through the production of volatile organic compounds. Importantly, rapid urbanization in India has increased the availability of artificial breeding habitats for Ae. aegypti, potentially facilitating the transmission and persistence of arboviral diseases. However, the composition of bacterial communities in these larval habitats and their potential role in shaping the oviposition behavior of Ae. aegypti remain poorly characterized in the Indian context. Here, we investigated the bacterial diversity and community composition of Aedes larval habitats during the 2024 Zika and chikungunya outbreaks in Pune, India. Water samples, collected from artificial urban containers and natural freshwater habitats, were subjected to 16S rRNA amplicon sequencing. Artificial breeding habitats exhibited significantly higher bacterial diversity and were enriched with Enterobacter spp. compared with natural habitats. Oviposition bioassays further demonstrated a strong preference of gravid Ae. aegypti females for Enterobacter-conditioned water. GCMS analysis of bacterial suspension identified indole as a prominent volatile metabolite associated with Enterobacter, suggesting its possible role in mediating oviposition site selection. Together, these findings provide insights into the microbial and chemical ecology of Ae. aegypti breeding habitats and establish a basis for investigating microbial volatile cues as potential targets for vector surveillance and environmentally sustainable attract-and-kill strategies.

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Stage-Specific Associations of Automated RPR With Treponema pallidum qPCR Positivity and Cycle Threshold in Early Symptomatic Syphilis: A Multicenter Study Using Specimens Collected During Routine Care

Kasamatsu, A.; Ohama, Y.; Tomo, Y.; Imai, K.; Nakayama, S.-i.; Omori, R.; Yamagishi, T.; Yasuda, M.; Akeda, Y.

2026-10-15 infectious diseases 10.64898/2026.10.14.26365521 medRxiv
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Background: Treponema pallidum quantitative polymerase chain reaction (qPCR) positivity and cycle threshold (Ct) by rapid plasma reagin (RPR), disease stage, and other characteristics are poorly characterized in routine-care specimens, leaving it unclear when qPCR of such specimens is informative for diagnosis. Methods: This Japanese multicenter cross-sectional study explored qPCR positivity and Ct by these characteristics. Nonblood specimens collected during routine care underwent qPCR at a central laboratory for this study. Bayesian logistic and normal regressions modeled positivity and mean Ct of TP0574 and polA with stage-specific continuous automated RPR terms, patient characteristics, collection site, and facility random intercepts. Estimates were standardized over the analyzed specimens. Population-group predictions were instead averaged within each group. Results: Among 154 nonblood specimens from 145 patients (71.7% non-MSM men and women) at 14 facilities, 109 (70.8%) were qPCR positive. At RPR 1, adjusted positivity was 72.2% (95% credible interval, 60.9%--82.9%) in primary and 43.8% (16.7%--69.9%) in secondary syphilis. Positivity showed a modest downward trend with RPR in primary but increased in secondary syphilis, reflecting a stage-by-RPR interaction (secondary-to-primary ratio of odds ratios, 1.78; 1.25--2.65). Predicted positivity showed an upward trend with RPR values among MSM; adjusted positivity was relatively high for genital/urethral/urinary and anal/perianal/rectal specimens. Adjusted mean Ct increased with RPR in primary and followed an inverted-U pattern in secondary syphilis. Conclusions: In primary syphilis, nonblood qPCR positivity was high even at low RPR. When serologic findings remain inconclusive in this stage, qPCR is highly recommended for securing an early diagnosis.

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Post-outbreak surveillance reveals contrasting circulation dynamics of West Nile, Usutu and Bagaza viruses in southern Portugal, 2021 - 2023

Fontoura-Goncalves, C.; Goncalves, D.; Pascoal, L.; Llorente, F.; Moraga-Fernandez, A.; Contreras, M.; Silva, T.; Almeida, T.; Pinho, C.; Minayo-Martin, S.; Valencia, V.; Fasanelo, M.; Lopes, A.; Abrantes, J.; Mello, G.; Costa, J. B.; Alves, P. C.; Ramirez, E. P.; Roiz, D.; Jimenez-Clavero, M.; Hofle, U.; Queiros, J.

2026-09-24 genetics 10.64898/2026.09.21.752589 medRxiv
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Mosquito-borne orthoflaviviruses pose a significant threat to human and animal health worldwide. In Europe, West Nile (WNV), Usutu (USUV) and Bagaza (BAGV) viruses have expanded their geographic distribution and are detected with increasing frequency. Following the emergence of BAGV in 2021, we investigated the circulation dynamics and genomic diversity of orthoflaviviruses in southern Portugal, where their epidemiology remains poorly understood. Active Orthoflavivirus surveillance was conducted in birds and mosquitoes during 2021-2023 using serological and molecular assays, complemented by viral genome sequencing and phylogenomic analyses. Viral RNA was detected in 3.5% (41/1,171) of birds, while seroneutralization assays identified an overall seroprevalence of 55.3% (503/910). WNV RNA (lineage-1, strains WMed-1.2 and WMed-1.3) was detected annually in resident birds, including Alectoris rufa, Cyanopica cooki and Garrulus glandarius (1.5%, 18/1,171), and in Culex univittatus mosquitoes (0.8%, 2/255). Together with a WNV-specific seroprevalence of 28.5% (259/910) in birds, these findings support sustained local circulation. USUV RNA (Africa 3.1 sub-lineage) was detected in A. rufa in 2021 and 2023 (0.2%, 2/1,171), but seroprevalence was low (1.3%, 8/623), consistent with intermittent circulation. BAGV RNA (genotype-2) was detected only during the 2021 outbreak in A. rufa and Emberiza calandra (1.8%, 21/1,171), although BAGV-specific antibodies (6.6%, 60/910) were detected for up to two years after the outbreak, suggesting continued exposure or low-level circulation. Overall, our findings reveal contrasting circulation dynamics of orthoflaviviruses in southern Portugal. Sustained WNV circulation implies the need to strengthen avian and human surveillance in Portugal to better assess its public health risk, while the sporadic detection of USUV and BAGV underscores the value of long-term, integrated One Health surveillance for improving early warning and preparedness for emerging mosquito-borne diseases.

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Genomic and proteomic insights into the virulence of a native Heterorhabditis indica-Photorhabdus akhurstii complex active against Spodoptera spp.

Peralta, C.; Torres-Sanz, N.; Palma, L.

2026-10-11 microbiology 10.64898/2026.10.10.758207 medRxiv
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A native entomopathogenic nematode isolate, Heterorhabditis indica Che4.1, was recovered from soils in Valencia (Spain), and its symbiotic bacterium, Photorhabdus akhurstii Che4.1, was isolated and characterized. Nematode identification was confirmed by ITS and 28S rDNA sequencing, while genome-based analyses supported the taxonomic assignment of the bacterial symbiont. The nematode-bacterium complex exhibited insecticidal activity against Spodoptera exigua and Spodoptera littoralis. H. indica Che4.1 showed an LC of 53.7 infective juveniles (IJs)/mL against S. exigua, comparable to that of the commercial reference Larvanem (54.3 IJs/mL). Against S. littoralis, Che4.1 exhibited an approximately twofold lower LC than Larvanem (77.3 versus 155.9 IJs/mL), with non-overlapping 95% confidence intervals. The complete genome of P. akhurstii Che4.1 consists of a single circular chromosome of 5.66 Mb encoding a diverse repertoire of putative virulence factors, including toxin complex (Tc) components, YenTc-like proteins, Mcf toxins, App-family proteins, Pra/Prb proteins, and chitinases, together with several predicted secondary metabolite biosynthetic gene clusters. LC-MS/MS analyses of bacterial culture supernatants and infected insect cadavers detected multiple predicted virulence-associated proteins, including Tc-related, YenTc-like, App-family, and Pra/Prb proteins. In addition, bacterial cell-free supernatants caused 68.8-81.3% mortality in S. exigua neonates under laboratory conditions. Together, these findings reveal a diverse repertoire of potential virulence determinants in P. akhurstii Che4.1 and demonstrate the insecticidal potential of its native nematodebacterium complex. The performance of H. indica Che4.1 relative to a commercial reference supports further evaluation of this isolate for biological control of Spodoptera spp., particularly under greenhouse and field conditions.

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Compound climate extremes predict dengue risk at operational lead times across Brazil

Fletcher, C.; Mila, C.; Moirano, G.; Araujo, E.; Lührsen, D.; Codeco, C.; Codeco Coelho, F.; Lowe, R.

2026-10-19 public and global health 10.64898/2026.10.16.26365716 medRxiv
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Brazil has one of the highest dengue burdens globally, with transmission influenced by climate events. Yet, the effects of compound climate extremes on dengue risk and prediction have not been quantified to date. Using a Bayesian spatiotemporal model of monthly dengue cases across 435 health regions from 2010 to 2025, we estimated relative risk associated with interacting long-lag and short-lag drought indicators and temperature anomalies across nine Koppen-Geiger climatic zones, adjusting for absolute temperature and El Nino-Southern Oscillation. Long-lag dry, mid-lag warm and short-lag wet conditions were associated with the highest relative risk in five climatic zones, with temperature anomalies modifying hydrometeorological dynamics more strongly in temperate than tropical areas. Climate covariates improved the prediction of case counts and outbreaks compared to baseline models at lead times of 1, 3, 6 and 12 months, and for the upcoming season 5 months ahead. Improvements were greatest in the Northeast, Southeast, and Midwest. Recent dengue incidence provided the greatest improvement at the 1-month lead, whereas combining incidence with climate information performed best at 3- and 6-month leads. We extended our framework to weekly state-level predictions of the season ahead to align with national public health planning. We proposed a multi-staged dengue forecasting approach to enhance early warning and response across Brazil.

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Spatiotemporal dynamics and environmental drivers of listeriosis hospitalizations in Spain (2016-2024): A One Health perspective

Garcia-Carretero, R.; Valle-Borrego, B.; Peiro-Villalba, C.; de-Juan-Alvarez, C.; Cenzual-Alvarez, G.; Quevedo-Soriano, S.-M.

2026-09-22 public and global health 10.64898/2026.09.15.26363098 medRxiv
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Background: Listeria monocytogenes causes invasive infections with high mortality. However, ecological studies linking human incidence to livestock and weather remain scarce. This retrospective study analyzed the geographical distribution of human listeriosis in Spain using nationwide hospitalization data, livestock censuses, and meteorological records. Methods: Negative binomial regression models, spatial autocorrelation (Moran's Index), and bivariate local indicators of spatial association (LISA) analysis were applied. Results: Between 2016 and 2024, 4,391 hospital admissions were recorded. The national mean incidence was 1.03 per 100,000 inhabitants, peaking in 2019. Bovine density was the primary environmental driver, with an 11% increased risk per 10 heads/km2. Weather-livestock synergies were observed: bovine-associated risk increased exponentially at higher temperatures ([~]21 C) and lower humidity (53%), whereas caprine-associated incidence peaked at cooler temperatures ([~]13 C). Spatial mapping revealed northern clusters for bovine reservoirs and southern segregation for caprine reservoirs, with no associations for ovine or porcine livestock. Conclusions: Zoonotic risk is environmentally conditioned, with weather acting as a biological trigger. This study highlights the critical role of ruminant farming practices and the need for a "One Health" surveillance approach that integrates meteorological and farming data to predict seasonal outbreaks and optimize food chain safety.

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Plasma proteomic profiling identifies country-specific diversity in visceral leishmaniasis patients across East Africa

Cunha, J.; Addisu, A.; Matano, D.; Younis, B.; Bayiyana, A.; Kumar, R.; Tiwari, R.; Engel, J.; Hogg, K.; Wiggins, R.; Biwott, W.; Osuna, F.; Ichugu, C.; Zeleke, A. J.; Ayele, E.; Sande, O. J.; Khalil, E. A. G.; Ibrahim, H. M. H.; Mahmoud, M. A.; Zakaria, A. I. B.; Adiko, B.; The Immstat@Cure Consortium, ; O'Toole, P.; D'Alessio, F.; Lacey, C. J. N.; Engwerda, C. R.; Sundar, S.; Mbui, J.; Hailu, A.; Mbuchi, M.; Musa, A.; Olobo, J.; Kaye, P. M.

2026-10-21 infectious diseases 10.64898/2026.10.16.26365713 medRxiv
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Background: Visceral leishmaniasis (VL) is the most severe form of leishmaniasis and is caused by parasites from the Leishmania donovani complex. VL is endemic in 54 countries, with East Africa (EA) accounting for [~]70% of the global burden. Therefore, there is a pressing need to prioritize VL research in EA. Transcriptomics analysis in rodent models and patients following treatment have shown that immune homeostasis is not restored by the end of treatment. However, comprehensive proteomic studies in VL remain scarce, and the few available studies were conducted outside EA. Methodology/Principal Findings: As a part of ImmStat@cure consortium, we used the Olink Reveal proximity extension assay to profile circulating proteins in VL patients from Ethiopia, Kenya and Sudan. By comparing patients at admission and 17 days after treatment with SSG-PM, we have identified a systemic Th1-cytotoxic inflammatory profile at admission, characterized by high abundance of IFN{gamma}, IL-1B, IL-6, and the granzymes A and B. Chemokines with high abundance included CXCL8/10/11, CCL3, CCL4, CCL8, CXCL8 and CCL20, consistent with the recruitment of monocytes, macrophages, T cells, and NK cells. There were also evidence of immune regulation/exhaustion, with high levels of PD1, PD-L2, IDO1 and KYNU. Although the immune profiles were similar at admission, country specific differences were observed after treatment. Kenyan patients exhibited a sustained inflammatory profile and signatures of myeloid recruitment, characterized by high levels of IL-1B, IL-6 , IL-12A, CXCL8, CCL2, CCL3, CCL4, CCL7 and CEBPB. Sudanese patients showed signatures associated with lymphocyte activation and immune regulation. Conclusions/Significance: These results highlight the complexity of the immune changes associated with VL, identifying both core conserved profiles at admission and country-specific profiles after treatment. The data provided here will provide a valuable resource for future comparative studies across more diverse different geographic regions, for linkage studies that assess the impact of parasite genotype on immune / metabolic response and for use during the evaluation of new therapies against VL.

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Community Knowledge And Attitude Towards Polio Immunization In Northern Nigeria

Muhammad, A. G.; Abar, I. O.; Sule, H.; Olim, A. N.

2026-09-29 public and global health 10.64898/2026.09.29.26364257 medRxiv
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ABSTRACT Background: Poliomyelitis remains a major public health concern where population immunity is incomplete and circulating vaccine-derived poliovirus (cVDPV) persists. Although Nigeria interrupted wild poliovirus (WPV) transmission in 2020, cVDPV cases continue to pose challenges, particularly in parts of northern Nigeria. Modern control strategies require a synergy of routine immunization, supplementary campaigns, disease surveillance, and community trust. Methods: This multicentre descriptive cross-sectional study evaluated community knowledge and attitudes towards polio immunization across 37 Local Government Areas (LGAs) in 20 states and the Federal Capital Territory (FCT). A multistage sampling strategy was utilized to select 1,850 adult respondents (50 per LGA) spanning rural, semi-urban, and urban settlements. Results: Overall, 40.4% (n = 747) of respondents demonstrated good knowledge, while 58.4% (n = 1,080) displayed positive attitudes towards polio immunization. A striking disparity was observed across residence classifications: respondents in urban/semi-urban LGAs exhibited significantly higher levels of good knowledge (51.7%, 569/1,100) compared to those in rural LGAs (23.7%, 178/750; {chi} = 144.00, df = 1, p < 0.001). Main sources of information were Questionnaire responses (53.6%) and community and Traditional leaders(17.2%). Conclusion & Recommendations: Substantial knowledge deficits persist in rural northern Nigerian communities despite generally favorable attitudes. Interventions must prioritize localized risk communication, involvement of traditional/religious leaders, strengthening routine primary healthcare integration, and targeting zero-dose children in hard-to-reach areas. Keywords: Poliomyelitis, Oral Polio Vaccine, Vaccine Hesitancy, Northern Nigeria, Community Health, Routine Immunization.

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Neoehrlichia mikurensis, where art thou? A negative analysis of 87 Swedish wild boars (Sus scrofa)

Lindell, H. M. K.; Jenkins, A.; Evens, K. C.; Dinnetz, P.; Lehtilä, K.

2026-10-04 ecology 10.64898/2026.09.29.755505 medRxiv
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Neoehrlichia mikurensis is widely detected in tick populations across Europe, yet its host range beyond small rodents remains poorly understood. Large wild mammals are frequently exposed to tick vectors, but their role in the transmission cycle of this bacterium is unclear. Wild boars (Sus scrofa) are among the most abundant large mammals in southern Sweden and commonly inhabit tick-infested environments, making them a potentially relevant host species. In this study, spleen samples from 87 wild boars collected between 2023 and 2025 across southern and central Sweden were analysed for the presence of N. mikurensis DNA using quantitative polymerase chain reaction. N. mikurensis DNA was not detected in any of the analysed samples, despite sampling in regions where the bacterium is known to be prevalent in ticks. These results indicate that wild boars may have a limited role in the maintenance of N. mikurensis in Sweden, although the possibility of rare or transient infection cannot be excluded. Despite being based on negative findings, this study contributes to a more comprehensive understanding of the host range of N. mikurensis and highlights the importance of continued evaluation of wildlife species in the transmission dynamics of tick-borne pathogens.

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High Schistosomiasis Prevalence in Urban and Rural Primary School Children from Kimpese Health District, Democratic Republic of the Congo

Karume, K. L.; Noyes, H.; Nyangiri, O.; Mulindwa, J.; Fataki, O. L.; Kiabanzawoko, O. N.; Kyong-Shin, R. F.; Nassuuna, J.; Elliott, A.; Masacuberta-Partal, M.; Lyaki, J.; Mukendi, J. P. K.; Mbemba, T. F.; Ngoyi, D. M.

2026-09-29 epidemiology 10.64898/2026.09.24.26363880 medRxiv
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Background Schistosomiasis is a parasitic disease caused by flatworms known as schistosomes. The infection cycle starts when people shed eggs through the stool or the urine. Larva infects freshwater snails to later infect humans through the skin during water based activities. Schistosomiasis is commonly associated with rural areas. In this study, we wanted to see if the schistosomiasis distribution is different in rural and urban areas, along with potential risk factors associated with schistosomiasis distribution. Methodology Fresh urine samples were collected from 1,699 school-aged children (5 - 15 years old) in urban and rural sites in the Kimpese health district. Prevalence of haematobium and mansoni schistosomiasis was determined using, respectively, the urine sedimentation and the Point-of-Care Circulating Cathodic Antigen test with a quantitative estimate of infection intensity obtained with an RDT-Reader. Collected risk factors were tested for association with schistosomiasis infection and its intensity. Results The overall prevalence of schistosomiasis found in urban and rural areas was 75% and 82% respectively, with higher prevalence of S. mansoni in rural schools, and higher S. haematobium prevalence in urban schools. The difference in total prevalence between schools in urban and rural areas was significant, X2 (1, N = 1699) = 13.03, p = .0003. S. mansoni intensity of infection was also higher in rural children (mean = 162 mV) compared to those in urban areas (mean = 76 mV) (p < 2e-16). Male gender, washing dishes in the river, and swimming were associated with schistosomiasis in urban areas. Age, Springs, and rivers were significant factors in rural sites. Age, river, and washing dishes in the river were factors associated with the intensity of infection. Conclusion Our results showed very high prevalence in both rural and urban areas, which implies that control programs should consider them with the same interest and also revise control strategies.

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Hepatitis E Virus Prevalence and Associated Risk Factors in Pregnant Women Attending Antenatal Consultations Niger Republic, 2025

Hassane, F.; Lagare, A.; Yacouba, A.; Ousmane, H.; Issa, M.; Magagi, L. H.; Aoula, B.; Kaka, B. K.; Diallo, O.; Djedenam, M.; DOUTCHI, M.; Mamadou, S.

2026-10-07 infectious diseases 10.64898/2026.10.05.26364823 medRxiv
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Background: Hepatitis E virus (HEV) is highly endemic in several African countries with high mortality rate among pregnant women. The prevalence of HEV in Niger among pregnant women is unknown. We hereby aim to report the prevalence and risk factors of HEV among pregnant women in Niamey, Niger. Methods: Blood samples were collected from pregnant women attending antenatal consultation in three selected Health centers in Niamey. Data were collected for socio demographic characteristics using a structured questionnaire. Samples were tested using ELISA and qRT-PCR for anti- HEV IgM and RNA detection respectively. HEV associated risk factors were determined using multivariate logistic regression models. Results: A total of 491 pregnant women were enrolled with mean age of 26.5 years. The prevalence of anti-HEV IgM antibodies was 17.1%, while HEV RNA was detected in 3.46% of participants, indicating recent and active HEV infection. Anti-HEV IgM seropositivity was more frequent among women aged 26-30 years and those in the third trimester of pregnancy. Gravidity was significantly associated with HEV RNA positivity (p = 0.032). In multivariable analysis, the use of well water was independently associated with HEV infection (aOR = 75.70; 95% CI: 1.23-4643.20; p = 0.039). Conclusion: In view of the high seroprevalence of HEV among pregnant women, preventive measures including hygiene sensitization should be prioritized. Further studies should be conducted to assess the real impact of HEV infection on maternal and fetal health.

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Diversity of egg parasitoids of stink bugs in France, with emphasis on Scelionidae parasitizing main Pentatomidae pests.

Bout, A.; Warot, S.; Cesari, L.; Hamidi, R.; Caravel, C.; Talamas, E.; Tortorici, F.; Ris, N.

2026-09-28 ecology 10.64898/2026.09.25.754315 medRxiv
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Stink bugs (Hemiptera Pentatomidae) are major agricultural pests worldwide, including both native and invasive species. In France, for instance, Halyomorpha halys has rapidly expanded its range, affecting key crops such as hazelnuts, apples, and vegetables. Meanwhile, several native, polyphagous species - Nezara viridula, Palomena prasina and, to a lesser extent, Graphosoma italicum - are re-emerging and impacting diverse crops because of changes in agricultural practices and climatic conditions. Egg parasitoids represent promising biological control agents for these pests, be it through conservation, augmentation or introduction biological control. However, their actual potential is not precisely documented due to a lack of ambitious surveys and possible taxonomic issues. This study aims to address this gap by compiling results obtained from various of egg parasitism surveys of Pentatomidae in France and implementing a large-scale DNA Barcoding approach (2000 individuals) for the emerged parasitoids. Our results indicate a high diversity of egg parasitoids, and detected some taxonomic issues and molecular inconsistencies that warrant further study. Among the three families of egg parasitoids recovered (Encyrtidae, Eupelmide, and Scelionidae), Scelionidae was the most abundant and diverse with nine species of Trissolcus (including the two adventive species, Tr. japonicus and Tr. mitsukurii) and four Telenomus species (including two unidentified to species). Scelionidae dominated the parasitoid assemblages associated with most of the Pentatomidae host species, except for H. halys for which the eupelmid Anastatus bifasciatus was the most common species.