Acta Tropica

Dengue transmission is strongly influenced by climatic conditions that affect mosquito population dynamics and virus circulation. In Southern Brazil, where dengue historically occurred at low levels, recent climatic anomalies may be contributing to the expansion of Aedes vectors and an increase in local dengue incidence. This study investigated the spatiotemporal association between climatic variables, Aedes mosquito infestation and dengue cases in Porto Alegre (Southern Brazil, 2018 to 2025). Entomological, surveillance and climatic data were analyzed using Morans I and LISA for spatial association, Kendall correlation, polynomial regression and LASSO to identify relevant drivers and develop predictive models of mosquito infestation and dengue incidence. A strong spatial association between Aedes aegypti and Aedes albopictus was observed, with persistent local clusters detected across all years. Annual climatic variables were associated with mosquito abundance in several districts. Overall, rainfall frequency had a stronger effect on Aedes aegypti abundance than accumulated rainfall. Temperature and lagged infestation indices showed strong association with both species and dengue incidence, with effects observed up to four weeks prior. Predictive models demonstrated good agreement between observed and predicted values, particularly within low to moderate infestation levels. Lagged variables were consistently retained in both mosquito infestation abundance and dengue incidence models, highlighting the importance of temporal predictors for anticipating vector dynamics and dengue risk. This approach is generally applicable for predicting Aedes infestation and disease incidence and emphasizes the importance of integrating entomological and climatic surveillance data to improve anticipation and detection of dengue risk periods and support more effective public health interventions.

Some Anopheles species that act as malaria vectors are members of species complexes, a concept whereby sibling species cannot be differentiated solely on the basis of morphological characters. Therefore, species complexes represent a major problem in malaria vector control, because within an Anopheles complex, vectors cannot be differentiated from non-vector species, unless molecular techniques are used to identify them. The Anopheles tessellatus species complex is an important potential vector in South, East, and Southeast Asia, including certain regions of Indonesia. However, no in-depth studies have been conducted on this species complex in that country. Therefore, this study investigated the taxonomic status of An. tessellatus from diverse populations across five Indonesian islands (Sumatra, Java, West Nusa Tenggara, East Nusa Tenggara, and Sulawesi) and identified interpopulation genetic variation based on molecular data of the ITS2, COI, and COII genes. Phylogenetic relationships were constructed using the Maximum Likelihood method. Haplotype and network analysis were also conducted. The results indicate that An. tessellatus constitutes a monophyletic group comprising three well-defined lineages that exhibit clear intraspecific genetic differentiation. Cluster 1 corresponds to the population of Sumatra, Cluster 2 represents population from Sulawesi, and Cluster 3 encompasses populations from Java, West Nusa Tenggara, and East Nusa Tenggara. These findings demonstrate high haplotype diversity and low nucleotide diversity within the species. Populations from West Sumatra, Manado, Tojo Una - Una, and North Morowali (Sulawesi) have the potential for speciation with a genetic distance of 0.61 - 0.94% for COI, between 0.81 - 0.95% for ITS2, and between 0.62 - 0.71% for COII. These findings underscore the need for further integrative studies to obtain a more comprehensive understanding of the An. tessellatus complex in Indonesia and its role in malaria transmission.

Urbanization in the 21st century has given rise to complex socio-environmental landscapes that contribute to spatial inequalities in health, particularly in the context of emerging infectious diseases, such as dengue fever. This study employs an urban systems framework to explore the multi-dimensional drivers of dengue risk in Ibague, Colombia, where Aedes mosquitoes thrive in diverse urban environments. We characterized the biophysical, socio-economic, and institutional properties of the urban landscape and employed hierarchical cluster analysis to define urban typologies at both census block and urban section levels. Our findings reveal significant differences in dengue incidence across these typologies, with higher rates associated with areas of high population density and commercial activity. Additionally, we examined the landscape configuration and its role in shaping dengue risk, identifying that diversity and intermixing of typologies had protective effects against dengue incidence. This research underscores the importance of considering multi-scale, socio-ecological factors in dengue risk assessments and highlights the need for targeted public health interventions that address the complex interactions within urban landscapes.

Anopheles albimanus (Nyssorhynchus) is featured as the main malaria vector on Hispaniola. However, five other Anopheles species have been reported circulating in the area; four of them belonging to the subgenus Anopheles (An. crucians, An. grabhamii, An. pseudopunctipennis, and An. vestitipennis) and another one to the Nyssorhynchus subgenus (An. argyritarsis). Previous studies on mosquitoes in the genus Anopheles have identified and characterized peptides from immunogenic salivary proteins, with several of these peptides being unique to the Nyssorhynchus and Anopheles subgenera. This underscores their potential use as biomarkers for differentiating exposure to Anopheles mosquitoes in both the Old World and New World. Since both Nyssorhynchus and Anopheles subgenera have been reported in Haiti, a series of ELISAs were conducted to quantify IgG antibody titers against three published antigenic anopheline salivary peptides (gSG6-P1, Peroxi-P3, and Apy-2) in 348 participants registered in Haitis multi-partner/multidisciplinary Malaria Zero Program. This study aimed to evaluate the intensity of human-vector contact with Anopheles from both subgenera in Grand Anse, Haiti. In addition, the study measured antibodies against a panel of Plasmodium falciparum antigens to determine any association between anti-parasite and anti-peptide antibodies. Significantly elevated IgG responses to Peroxi-P3 in comparison to Apy2 and gSG6-P1 in the total study population (p < 0.001) were observed. Additionally, immune responses to Peroxi-P3 and gSG6-P1 differed significantly between [&le;]18-year-olds and >18-year-olds (p = 0.004 and p = 0.002), whereas no sex-based differences were observed for any peptide. Correlation analyses observed a greater number of significant positive associations in immune response between gSG6-P1 and Plasmodium antigens than any other salivary peptide, an occurrence which was more pronounced in [&le;]18-year-olds than >18-year-olds. A marked reduction in IgG responses to Apy2 and Peroxi-P3, but not gSG6-P1, among participants who kept a single household animal species compared with those who owned two or more species or those who did not have household animals was also demonstrated. Spatial analysis revealed heterogenous geographic overlap of high antibody responses among Peroxi-P3, Apy2, and gSG6-P1, alongside geographically overlapping clusters of low antibody responses to Peroxi-P3 and Apy2. These results provide additional data on the utility of anopheline salivary peptides to characterize human-vector-parasite exposure dynamics in low-transmission areas, such as Haiti.

Accurate species identification is crucial to assess the medical and veterinary relevance of a mosquito specimen, but it requires high experience of the observers and well-equipped laboratories. This study aimed to evaluate whether low-cost imaging in combination with geometric wing morphometrics can provide accurate identification of invasive, morphologically similar Aedes species. The right wings of 670 female specimens covering 184 Ae. aegypti, 156 Ae. albopictus, 166 Ae. j. japonicus and 164 Ae. koreicus, were removed, mounted and photographed with a professional stereomicroscope (Olympus SZ61, Olympus, Tokyo, Japan) and a macro lens (Apexel-24XMH, Apexel, Shenzhen, China) attached to a smartphone. The coordinates of 18 landmarks on the vein crosses were digitalized by a single observer for each image. In addition, the landmarks of 20 specimens per species and imaging device were digitalized by six different observers to assess the degree of the observer error. The superimposed shape variables were used to compare the species classification accuracy of linear discriminant analysis (LDA), support vector machine (SVM), Random Forest (RF), and XGBoost. In the single-observer landmark data, the LDA achieved the best classification results with a mean accuracy of 95 % for landmarks from microscope images and 92 % for those obtained from smartphone images. In the multi-observer landmark data, LDA consistently performed worse than the other three classifiers, and the reduction in the accuracy was more pronounced for smartphone images than for microscope images. This pattern was associated with a higher degree of observer error for smartphone images, as confirmed by a landmark-wise comparison across all landmarks. Geometric wing morphometrics provides a reliable method to distinguish the most common invasive Aedes species in Europe. Thereby, the image quality obtained by smartphones equipped with a macro lens is sufficient and represents a cost-effective alternative to professional microscopes. However, due to the greater degree of observer variation for smartphone images, landmark coordinates for such images should ideally be collected by a single observer.

Astyanax Baird & Girard, 1854 is a widely distributed and species-rich genus of Acestrorhamphidae, whose abundant populations in Neotropical basins play a crucial ecological role at the trophic level. Taxonomic uncertainties persist within the genus, as seen in Astyanax sp. (formerly designated as A. fasciatus) from the Magdalena basin in Colombia. Concerns about its genetic status are heightened due to ecological threats posed by hydroelectric dams, from habitat loss to river connectivity. We isolated and characterized 17 microsatellite loci to assess the population genetics of this species in a broad sample from the middle and lower sections of the Cauca River, now interrupted by the Ituango dam. Furthermore, a multidisciplinary approach integrating phylogenetic analyses of mitochondrial (COI) and nuclear (rag2) markers with geometric morphometric analyses was employed to evaluate potential cryptic diversity within Astyanax sp. Microsatellites revealed two genetic groups in the studied area, strongly supported as distinct lineages by phylogenetic analyses. Unexpectedly, one of these lineages of Astyanax sp. was recovered in an unresolved clade with samples of A. microlepis and allopatric samples of A. viejita from the Maracaibo Lake basin. Each genetic group showed high genetic diversity, but also evidence of recent bottleneck events and significant-high values of inbreeding. Morphometric analyses provided evidence of significant phenotypic differentiation among A. microlepis, Astyanax sp. 1 (Asp1), and Astyanax sp. 2 (Asp2). Morphological patterns ranged from the robust profile of A. microlepis to the streamlined shape of Astyanax sp. 2 (Asp2), with Astyanax sp. 1 (Asp1) displaying intermediate traits and localized differences in head length and fin placement. Statistical support from permutation tests and a high overall classification accuracy (95.65%) underscore the existence of distinct morphospecies, suggesting that phenotypic differentiation is well-established, despite the complex evolutionary history of the group. This study suggests the presence of cryptic diversity within Astyanax sp. and provides valuable genetic information for the conservation and management of their populations in the Magdalena basin.

Background: Leptospirosis is a neglected tropical disease with substantial public health impact in Brazil, closely associated with socio-environmental vulnerabilities and climatic extremes. This study analyzed the epidemiological profile, spatiotemporal distribution, and climatic influences on leptospirosis incidence and lethality in Brazil from 2015 to 2024. Methods: An ecological time-series study was conducted using secondary data from the Notifiable Diseases Information System (SINAN). Variables included geographic region, probable infection environment, occupational, and educational level (ISCED-2011). The spatiotemporal correlation between disease incidence and El Nino-Southern Oscillation (ENSO) anomalies was assessed using the Oceanic Nino Index (ONI) and Spearman's rank correlation coefficient. Results: A total of 31,397 cases were notified, with an annual average of 3,140 cases. The South and North regions exhibited the highest incidence rates, while the Northeast and Southeast presented lethality rates above the national average (9.20%). A marked reduction in notifications occurred during the COVID-19 pandemic. Contaminations occurred predominantly in the domiciliary environment (64%). Rural workers (27.45%) and civil construction workers (18.63%) were the most affected occupational groups, with a higher incidence among illiterate and low-education populations. Climatic analysis revealed a positive spatial correlation between El Nino intensification and leptospirosis incidence in the South and Southeast, and a negative correlation in specific Northeastern states. Conclusion: The dynamics of leptospirosis in Brazil are complex and multifactorial, strongly influenced by macroclimatic variations and driven by deficits in basic sanitation and urbanization. Mitigating the disease burden requires sustained, region-specific public health strategies, targeted infrastructure improvements, and enhanced epidemiological surveillance to address underreporting.

In wildlife forensic practice, species identification and estimation of the Minimum Number of Individuals (MNI) for highly processed specimens have long relied on weight-based conversion methods, which may result in underestimation of the number of individuals involved in a case. Focusing on confiscated casque products of the helmeted hornbill (Rhinoplax vigil), this study combines macroscopic morphological examination with mitochondrial DNA barcoding (16S rRNA, COI, and Cytb) to explore a more robust approach for individual quantification. The results demonstrate that the conventional "weight-based" approach overlooks critical biological information contained in anatomical structures and cannot accurately reflect the actual number of individuals involved. Based on this, we propose an anatomy-based criterion centered on the principle of structural uniqueness: specimens retaining biologically unique beak or casque structures should be directly assigned to a single individual, whereas weight-based estimation should only be applied when original anatomical features are entirely absent. In addition, considering material loss during processing, we propose approximately 85 g as a reference threshold for estimating the number of individuals in heavily processed solid casque products. This approach improves the scientific rigor and accuracy of forensic identification and provides reliable technical support for the conviction, sentencing, and law enforcement of wildlife trafficking cases involving helmeted hornbill and other endangered species.

Human leptospirosis is a disease of public health importance in Thailand, but the animal species involved in the transmission cycle have not been fully uncovered. This study investigated Leptospira infection in dogs and terrestrial micromammals in rural Nan Province, Thailand, and the pathogen diversity. Sera from 95 seemingly healthy dogs and kidney samples from 399 micromammals were analyzed using real-time PCR for Leptospira detection, followed by conventional PCR and sequencing of infecting Leptospira. We investigated environmental factors associated with Leptospira infection in micromammals, using data collected during trapping. Real-time PCR revealed ongoing infection in 8.4% (8/95) of dogs and 10.0% (40/399) of terrestrial micromammals, with 12 infected species including Bandicota indica, Berylmys berdmorei, Berylmys bowersi, Mus cervicolor, Mus cookii, and Hylomys suillus. In this qPCR-positive micromammals, three pathogenic Leptospira species were identified: L. interrogans, L. weilii, and L. borgpetersenii. This represents the first confirmed detection of L. weilii in rodents in Thailand. Infected micromammals were found in agricultural and forest habitats but not in human settlements. Our study demonstrates potential complex leptospirosis epidemiology in rural Thailand, with multiple species serving as pathogenic Leptospira reservoirs across diverse habitats, and some shared pathogen diversity with human leptospirosis cases in Thailand. Free-roaming dogs may serve as bridge hosts, transmitting zoonotic Leptospira from micromammals to humans by visiting both animal habitats and human settlements. These findings emphasize the need for integrated One Health surveillance approaches to control leptospirosis in rural communities.

Introduction: Rickettsial infections are vector borne diseases and seroprevalence shows regional and population based variation. This prospective study assesses the seroprevalence and factors associated with rickettsial infections in different geographical regions of Northern Tamil Nadu, India. Methods: A community based cross sectional study was performed among 2565 individuals in five districts in Tamil Nadu who consented and provided 4 ml blood samples. A semistructured questionnaire was administered to gather information on sociodemographic and environmental parameters. The serum IgG antibodies to scrub typhus (ST), spotted fever (SF), murine typhus (MT) and Q fever (QF) were detected by ELISA and the optical density (OD) recorded. EpiData was used for data entry and SPSS for analysis. Results: The seroprevalence of ST, SF, MT and QF was 14%, 9.1%, 3.7%, and 5.7%, among the study population. For ST, age >35, people living in rural and <1000 MSL, farmers, sleeping on the floor, lack of toilet at home, and grass near the home were associated with higher risk. For SF, people living at 501 to 1000 MSL elevation, no toilet at home and having pet animal were associated with higher odds. Females, 46 to 55 and >65 years, people residing in urban areas and elevation upto 500 MSL, those who sleep on the floor, not changing clothes daily and with pet at home were associated with higher odds of MT. Whereas Q fever was more likely to affect who sleep directly on the floor, residing in urban and do not have pets. Conclusion: Scrub typhus is the most common rickettsial infection followed by spotted fever in Northern Tamil Nadu. Factors associated with prevalence vary for different rickettsial diseases and include personal and lifestyle behaviors. The findings of this study need to be verified by multicentre cohort studies.

The tropical house cricket Gryllodes sigillatus is a major species used in the edible insect farming industry. Despite the rapid expansion of this sector, diagnostic tools for detecting infections in these species remain limited. The lack of validated reference genes compromises the reliability of RT-qPCR-based gene expression analyses, which are essential for the development of molecular tools for disease diagnosis and health monitoring in insect production systems. To address this gap, we evaluated the expression stability of six candidate reference genes (ACTB, EF1, GAPDH, HisH3, RPL5, and 18SrRNA) across four body parts (abdomen, head, legs, and whole body) using a combination of complementary statistical approaches, including geNorm, NormFinder, BestKeeper, the {Delta}Ct method, the R statistical environment, and the integrated RefFinder tool. Candidate genes were identified and annotated using the recently published G. sigillatus genome, through sequence comparisons with closely related insect species using BLAST and reciprocal BLAST analyses, multiple sequence alignments. All procedures complied with MIQE 2.0 guidelines to ensure methodological rigor and transparency. The results showed that ACTB, EF1, RPL5, and 18SrRNA exhibited stable and consistent expression across all analyzed tissues, whereas GAPDH and HisH3 displayed high variability and were generally unsuitable for normalization, except in head tissue where GAPDH remained stable. This study provides the first validated set of reference genes for G. sigillatus, establishing a robust foundation for accurate, reproducible, and comparable gene expression analyses. Furthermore, these findings support the development of RT-qPCR-based diagnostic tools, contributing to improved health monitoring and biosafety in insect production systems.

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

Natural extracts could improve sperm storage and artificial insemination (AI). This study, for the first time, evaluates the suitability of a blueberry extract (Vaccinium corymbosum) obtained from pomace using a sustainable methodology as a supplement for bull semen extenders. Cryopreserved semen doses from eight bulls were combined in 9 pools (3 bulls/pool), supplemented with 0%, 1%, 5%, or 10% extract, and incubated up to 5 h at 38 {degrees}C. Motility was assessed hourly using OpenCASA, and the effects of treatment and time were evaluated using linear mixed-effects models. Motility was significantly better preserved with 1% extract (total and progressive motility, improved linear velocity and linearities, and decreased BCF and fractal dimension, related to hyperactivation). The effect of 5% was overall positive, but it was below 1%, whereas 10% mostly showed a negative effect. These results show that this natural extract could safely supplement bull semen extenders at least between 1% to 5%, and even help improve sperm motility. Therefore, this extract offers an opportunity to enhance cattle semen extenders using a sustainable approach, potentially improving reproductive outcomes.

IntroductionSevere dengue infection is characterized by endothelial injury and systemic inflammatory complications. To better understand the mechanisms underlying disease severity, we investigated a broad panel of circulating inflammatory and endothelial mediators in patients with clinical dengue infection. MethodsA prospective cross-sectional case-control study was carried out involving 111 dengue patients and 42 healthy controls. Among the dengue cases, 85 were identified as primary, while 26 were classified as secondary dengue infections. Serum levels of endothelial markers (Ang-2, CXCL10, MCP1, TRAIL), acute-phase and liver dysfunction and acute-phase markers (CRP, galectin 3, and serum amyloid protein), systemic inflammatory mediators (MIF, TNF-, IL-1{beta}), mast cell-derived proteases (chymase, tryptase), and tissue repair markers HGF, IL-10, IL-1Ra) were quantified using ELISA and Luminex multiplex assays. Correlations among serum analytes, severity indicators, and haematological markers were also explored ResultsSeveral biomarkers, Ang-2, CXCL10, TRAIL, CRP, MIF, IL-1Ra, TNF-, and chymase showed differential expression across severity groups, indicating coordinated endothelial and inflammatory activation. Stratification of patients with primary-secondary dengue also followed a similar pattern except IL-1{beta}, which had significant differential expression across the cohorts. Ang-2 showed strong positive correlations with markers of hepatic dysfunction, including ALT, AST, and bilirubin, suggesting a link between endothelial injury and liver involvement. ConclusionsSevere dengue is driven by the coordinated activation of endothelial dysfunction, acute-phase responses, mast cell mediators, and counter-regulatory pathways. These processes collectively contribute to vascular leakage and organ injury, reinforcing the value of biomarkers such as Ang-2, CXCL10, CRP, and chymase for severity assessment.

Mosquitoes in urban environments are considered unpleasant by citizens, and they can represent serious health risks as disease vectors. Invasive Aedes species are continuously spreading in Europe and have been increasingly reported from urban settlements. Some of these mosquito species have been associated with small artificial habitats. Therefore, their presence may also be expected in small plastic garden ponds, which are numerous in urban settings across many parts of Europe. Here, we aimed to determine whether urban waters host a high occurrence of mosquitoes and to identify the potential abiotic, biotic and landscape drivers of mosquito presence and abundance in urban ponds. We sampled 53 urban ponds in the city of Budapest (Hungary) of both natural and anthropogenic origin, and 40 garden ponds, which cover both highly urbanised areas and those with high green index in the suburbs. We collected data on macroinvertebrate communities, pond management, physico-chemical parameters, and pond characteristics (mainly morphology and vegetation cover) measured in situ. Two different mosquito detection techniques were used: dip-net sampling and eDNA. While only one invasive species (Aedes koreicus) was detected, occurring in a single pond, several other species were present, including potential malaria vectors increasingly reported from urban environments: the Anopheles maculipennis complex, An. claviger and An. plumbeus. Fish presence was negatively associated with both the presence and abundance of mosquitoes, regardless of pond type. Contrary to expectations, urbanisation did not play a major role in explaining mosquito presence or abundance. These results highlight the importance of local pond characteristics, and particularly the role of fish presence, in regulating mosquito populations in ponds in the urban landscape, although the broader ecological effects of fish on pond communities should also be considered.

Background: Mobile laboratory diagnostic technologies for Nipah virus outbreak prevention, mitigation and response remain limited, despite the critical need for such capacities in remote, low-resource regions where most cases occur. We aim to address this gap by implementing a workflow that includes method development, laboratory validation, and field demonstration of a mobile Nipah virus complex diagnostic solution. Methods: We developed a flexible mobile laboratory workflow incorporating PCR capacity, a novel amplicon-based sequencing protocol, and a validated Nipah virus inactivation procedure. Following development and validation, we demonstrated the feasibility of this workflow through repeated field sampling of bat colonies in Nipah virus endemic regions of Bangladesh across multiple field campaigns. Findings: We demonstrated the feasibility of this system for early outbreak response and as a potential early warning tool prior to the emergence of human cases. We detected two urine samples from flying foxes that tested positive and performed full-scale on-site analysis, including qPCR diagnostics and NGS sequencing, within 24 hours. Interpretation: As highlighted in the present study, active surveillance enables outbreak prevention by identifying bat colonies that are actively shedding viruses in real time, even in rural settings. Also, this method can provide rapid, on-site sequence data to track and better understand the genomic diversity of Nipah virus in natural reservoirs during both outbreak and non-outbreak periods. In this study we aimed to establish the foundations of a standard procedure for safe and rapid field testing of Nipah virus in remote areas.

Background: Spotted fever is caused by spotted fever group rickettsiae (SFGR) belonging to the genus Rickettsia. Transmission to humans is primarily via the bite of infected ticks. Being a vector-borne disease, the occurrence of spotted fever is related to factors that allow the vector to thrive. This spatio-temporal analysis gives an insight into the distribution of cases and correlation with seasonality. Methodology: A suspected AFI patient was considered spotted fever positive if either serology (ELISA/IFA) or molecular assay (Nested PCR/qPCR) was tested positive. Demographic data of confirmed cases were included for the analysis. Results: In the 18-year dataset, a total of 2153 suspected patients were tested for spotted fever, of which 516 (24%) were positive. On spatio-temporal analysis, Vellore district reported 39.9% of cases, Chittoor 38.8%, Tirupattur 12.5%, Ranipet 4.5%, and Tiruvannamalai 4.3%. Maximum spotted fever cases were reported between the months of September to March, with a peak in January. Children below 10 years and housewives were at risk of spotted fever. Conclusion: The findings of this retrospective analysis highlight the importance of considering spotted fever group rickettsioses in patients presenting with acute undifferentiated febrile illness, particularly children aged <10 years, from areas with higher spatial clustering, during or following the monsoon season.

Scorpionism is a public health concern in warm regions, particularly affecting children under 10 years old. Timely treatment with antivenom, provided free by the Brazilian Unified Health System, at strategic care points (PEs) is crucial to prevent avoidable deaths. Our study focused on the Sao Paulo state (SP), which has the largest population in Brazil. The objectives were to adapt a network analysis method suited to SPs context; to assess the efficiency of the SP PE network coverage, considering the 90-minute response time; and to determine the ideal number of vials to be stored at each PE. After adapting the healthcare network analysis, we applied spatial coverage models to evaluate the adequacy of PE response times. We also estimated the demand for antivenom vials at each PE based on Notifiable Diseases Information System data from 2021 to 2023, which is currently limited to the state level. We identified 12 areas lacking coverage, of which only one was suitable for a new PE. The estimated serum requirements aligned with SP's current distributions. However, the estimation carried out according to the PEs has the advantage of reducing the risk of antivenom shortages, especially in emergencies, thus ensuring timely care to prevent avoidable deaths. Our adapted method and PE serum estimates can enhance the scorpion sting care system by supporting geographic planning and optimizing resource allocation. Moreover, these findings and methodologies have potential applicability to other Brazilian regions and warm countries facing similar challenges, contributing to improved access and outcomes for scorpionism victims.

BackgroundThe malaria transmission potential and the vulnerability of Anopheles mosquitoes to different vector control methods depend, among other factors, on the endophily, endophagy, anthropophagy and survival of each species. Local information on these bionomic parameters is generally unavailable. MethodsTo address this, we estimated species-specific values of these parameters using an augmented version of the global database of bionomics data by Massey et al. (2016). We applied inclusion and exclusion criteria to select eligible studies with relevant experimental designs that minimise bias from collection methods for parous, sac, endophagy, and endophily rates as well as for the resting duration. For the human blood index (HBI), we separated data from indoor and outdoor collections. We fitted hierarchical Bayesian models with levels based on Anopheles taxonomy to estimate these quantities. Based on the estimated bionomics, we quantified the expected vectorial capacity reduction after the introduction of a pyrethroid-pyrrole insecticide-treated net (ITN) for 57 Anopheles species. ResultsWe identified 26 eligible studies for endophagy and 61 for the parous rate, leading to a Bayesian posterior average for the Anopheles genus of 42% (95% credible interval: 18-70) and 55% (32-77) respectively. HBI values widely varied depending on the location of collection, except for some species showing strong anthropophilic behaviours. Resting duration was estimated to be 2.1 days (1.2 - 4.8) at the genus level. Few studies were available to estimate the sac and endophily rates, which prevented us from deriving precise estimates for the whole Anopheles genus. Our estimates of the vectorial capacity reduction following the introduction of a pyrrole-pyrethroid ITN ranged between 48% and 76% across species, highlighting the important differences among mosquito species in vulnerability to vector control interventions. ConclusionThis work demonstrates how data from both Anopheles species complexes and individual species can be leveraged to generate species-specific estimates of bionomic parameters, capturing the local characteristics and behaviour of malaria vectors. The dataset is readily updatable as new data become available. However, more frequent and standardised field surveys are still needed to accurately characterise local vector behaviour.

BackgroundThe World Health Organization (WHO) has raised concerns over increasing Pfhrp2/3 deletions, undermining the sensitivity of Pfhrp2-based rapid diagnostic tests (RDTs). Close monitoring of the population and a change in diagnostic methods are recommended if the prevalence of parasites with Pfhrp2/3 deletions exceeds 5%. In high transmission settings, accurate estimates are hampered by the frequent occurrence of mixed-clone infections (multiplicity of infection; MOI). Objective and MethodsIf parasites with and without deletions are present in an infection, standard molecular assays cannot detect the presence of the former. To accurately estimate frequencies of haplotypes with Pfhrp2/3 deletions in the presence of mixed infections, a novel statistical model that combines genetic/molecular information from Pfhrp2/3 with that from neutral markers is introduced. Maximum-likelihood estimates (MLEs) are obtained for haplotype frequencies characterized by markers at Phrp2/3 loci and loci for neutral markers. The expectation-maximization algorithm is used to derive the MLEs. The adequacy of the method (precision and accuracy) is assessed by numerical simulations. ResultsThe method was applied to an active surveillance study conducted in a tribal community in Jagdalpur, India, which enrolled febrile community members (n = 432) between October and November 2021. Four markers each at Pfhrp2 and Pfhrp3 are combined with one marker each at Pfmsp1 (which encodes P. falciparum merozoite surface protein 1) and Pfmsp2. Data from a total of 117 patients who had both P. falciparum infections and genetic information for the molecular markers underwent further analysis with the novel statistical method. ConclusionResults indicate that this novel method has promising statistical properties (asymptotic and in finite samples) and can be readily applied to real-world situations. A stable implementation of the method in R is provided. This novel approach enables accurate estimation of Pfhrp2/3 deletion frequencies in complex P. falciparum infections, addressing a key limitation of current molecular surveillance methods. Author summaryPlasmodium falciparum (Pf) causes the most severe form of human malaria, accounting for over 90% of cases. Rapid diagnostic tests (RDTs) have become a cornerstone of malaria control. These RDTs detect Pf-specific antigens in a blood drop. HRP2/3 emerged as the best antigen for such tests because it is Pf-specific and expressed in abundance. However, some parasites lack the genes that code for HRP2/3 proteins. If parasites in an infection have such gene deletions, RDT results can be false negative. The WHO considers the containment of such deletions a public health priority and recommends monitoring their prevalence. The detection of HRP deletions is challenging if parasites with and without deletions co-occur in infections because standard molecular assays cannot detect deletions in this situation. To overcome this challenge, we introduce a novel statistical method to estimate the frequency distribution of parasite variants with deletions. The method combines information from neutral molecular markers and from HRP-related markers to correct for unobservable information. Here we provide a derivation of the statistical model, a stable implementation, and test its statistical properties with synthetic and real data, thereby showing that our method is well-suited for the underlying problem.