Journal of Medical Entomology
◐ Oxford University Press (OUP)
Preprints posted in the last 30 days, ranked by how well they match Journal of Medical Entomology's content profile, based on 18 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.
Sacco, N.; Perriat-Sanguinet, M.; Makoundou, P.; M'Sakni, A.; Manuella, v. M.; Boëte, C.
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Aedes albopictus is a major arboviral vector whose global expansion, driven by human activities and climate change, poses a growing public health concern for a number of neglected tropical diseases in both tropical and temperate regions. As a poikilotherm, its biology and population dynamics are strongly influenced by temperature, thereby shaping disease transmission. To thwart and control its geographic expansion, effective vector control strategies are increasingly critical. Densoviruses (DVs), such as AalDV2, are being explored as mosquito viral biocontrol agents due to their restricted host range and ability to disseminate through oviposition sites. However, the influence of environmental parameters on the interactions between Ae. albopictus and AalDV2 remains poorly understood. This makes their performance under realistic, fluctuating thermal regimes difficult to estimate. In this study, we investigated the combined effects of temperature and AalDV2 exposure on Ae. albopictus survival and development across its full life cycle. Mosquitoes were reared under fluctuating temperature regimes (26-28 {degrees}C and 32-34 {degrees}C, 12:12 day[ndash]night cycles) and exposed to AalDV2 or a control treatment. Chronic exposure to 32-34 {degrees}C significantly reduced overall survival, decreasing median lifespan by approximately 10 days (HR=2.21, p=0.0018), with a deleterious effect increasing over time. It extended aquatic lifespan and increased pupal mortality. It also reduced adult lifespan in both sexes with a stronger effect in females. AalDV2 exposure had no significant effect on overall survival, stage-specific mortality, or adult lifespan. However, a significant interaction between viral exposure and thermal stress was detected on aquatic lifespan: AalDV2-exposed females showed further extended larval and pupal development specifically under the 32-34 {degrees}C regime, without any effect on survival. These results indicate that the biocontrol potential of AalDV2 cannot be assessed independently of thermal context: while lethal effects were absent under both fluctuating regimes, the prolongation of aquatic development by the virus under thermal stress may have indirect consequences for mosquito population dynamics that warrant further investigation.
Wang, S.; Carruth, S. G.; Vasquez, C.; Townsend, J.; Raman, V.; Mutebi, J.-P.; Ajelli, M.; Wilke, A. B. B.
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Locally acquired arboviral infections are an increasing public health concern in the United States. Aedes aegypti and Culex quinquefasciatus, vectors of dengue virus and West Nile virus, respectively, are established in regions where local transmission has been reported. Seasonal variation in mosquito abundance affects vector density, human-vector contact, and arbovirus transmission risk. The aim of this study is to investigate seasonal variations in Ae. aegypti and Cx. quinquefasciatus population dynamics in Miami-Dade County, Florida; Maricopa County, Arizona; and Clark County, Nevada. Monthly relative abundance, average mosquitoes collected per trap-night, normalized abundance ratios, and seasonal-trend decomposition were used to evaluate species- and location-specific seasonal patterns. Mosquito population dynamics differed by species and location. In Miami-Dade County, the two species showed seasonal turnover, with Cx. quinquefasciatus peaking during winter and spring and Ae. aegypti peaking during summer. In Maricopa and Clark counties, both species peaked primarily between August and September. Species dominance also differed by site, with Ae. aegypti more abundant than Cx. quinquefasciatus in Maricopa County and Cx. quinquefasciatus more abundant than Ae. aegypti in Clark and Miami-Dade counties. Seasonal decomposition showed that Ae. aegypti peaked earlier in Miami-Dade County than in Maricopa and Clark counties, whereas Cx. quinquefasciatus showed a spring peak in Miami-Dade County and bimodal seasonal patterns in Maricopa and Clark counties. These results suggest that mosquito population dynamics are species- and location-specific and support the use of local surveillance data to guide the timing of mosquito control and arbovirus preparedness.
Diallo, M.; Dao, A.; Sanogo, Z. L.; Cisse, K.; Coulibaly, B.; Samake, D.; Krajacich, B.; Assitoun, A.; Traore, M.; Poudiougo, J.; Bamou, R.; Kouam, C.; Faiman, R.; Yaro, A. S.; Lehmann, T.
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Despite extensive efforts to understand the population biology and ecology of the African malaria mosquitoes questions regarding their movement pattern, survival, and population size persist, reflecting methodological limitations. Site fidelity, in which mosquitoes return to feeding sites, resting sites, or oviposition sites remain debated. Mark release recapture (MRR) studies are vital to address such questions. Using locality- and date-specific DNA tags in fluorescent spray, we carried out a continuous MRR in a Malian village from September to December 2019 with three days interval between capture and release across seven zones. A total of 12,937 Anopheles gambiae s.l. (7,455 females) were captured during 35 indoor collections. Handling related mortality was 3.4%., A. coluzzii predominated (89.7%), followed by A. gambiae (9.4%), and A. arabiensis (0.9%). Overall recapture rate was 1.05% (N=129). Contrary to the site-fidelity hypothesis, the distribution of recaptured mosquitoes across zones (regardless of their zone of release) was similar to the distribution of the captured mosquitoes (r=0.97, P<0.001), with 70% recaptured in a different zone. There was no difference in distance moved between sexes, but males average distance increased over time since release, whereas females distance remained unchanged. Simulated movements (across released points), with equal probability to reach any of the village houses predicted actual distance moved by mosquitoes. The regression of observed distance from each zone over predicted had a slope of 1 (r2=94%, P=0.006), suggesting that the layout of the capture area greatly affected the results. The average days post release (minimum age of wild captured mosquitoes) for recaptures was 6.4 d with the longest being 30 d. No seasonal and sex related difference in minimum age were detected. The corrected probability of daily survival (PDS) was 94% and the daily increase in sporozoite rate was 4.9%. Limiting the recapture duration period showed that PDS increased with recapture duration from 74% to 86% (12 to 30 d, uncorrected). Thus, larger recapture area and longer recapture duration are needed to obtain accurate estimates of movement range and of daily survival.
Geng, L.; Ross, P. S.; Cai, Y.; Huang, T.; Chow, J.; Wang, Z.; Choo, E. L. W.; Chang, C.-C.; Couper, L.; Gu, X.; Hoffmann, A.; Lim, J. T.
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Wolbachia-mediated incompatible-insect technique (IIT) via wAlbB, wMel or wPip/wAlbA/wAlbB strains are promising approaches for suppressing wildtype Aedes mosquitoes and therefore Aedes-borne diseases. Yet, the effectiveness of this technique under climate change remains uncertain. Here, we evaluate the long-term robustness of male Wolbachia-infected mosquito releases to suppress wildtype Aedes aegypti and Ae. albopictus populations across future climate scenarios across diverse geographical regions. We compiled large publicly available datasets on Aedes abundance across Singapore, China, the European Union and the United States, historical and projected climatic conditions in these regions and conducted experiments to test the thermal stability of cytoplasmic incompatibility in Wolbachia-infected male Aedes aegypti and albopictus. A climatically-driven entomological model was developed and calibrated using a Bayesian approach to model observed Aedes population dynamics and infer area-specific climate-driven variation in mosquito life-history traits. We back-inferred historical mosquito abundance and projected mosquito abundance in future climate change scenarios incorporating experimental and locally inferred entomological parameters and then simulated the counterfactual implementation of IIT in these regions. We find that Aedes populations are projected to increase in most regions across all climate change scenarios from 2050-2100 even under high heat conditions in the absence of interventions. While we found that IIT can suppress wild-type populations effectively across all future scenarios and in high heat conditions, effectiveness was found to depend heavily on mosquito emigration rates, overflooding ratios, release intervals and release strategies Extensive robustness checks confirmed that the model reproduced historical temporal trends, captured the influence of individual parameters on outcome and was sensitive to changes in values of inferred parameters and implement policy. These findings demonstrate that IIT may be a robust vector control tool under future climate conditions.
Bennett, K. L.; Schmidt, T. L.; Day, J. P.; Gutierrez Alvarado, J. M.; Delgado, G.; Marin Rodriguez, R.; Fernando Chaves, L.; Labau, J. I. R.; McMillan, O. W.; Jiggins, F.; Loaiza, J. R.
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The global invasion of the Asian tiger mosquito Aedes albopictus has led to an increase in arboviral disease, including within Mesoamerica. Understanding vector invasion routes is important for public health because it directs biosecurity and identifies sources of adaptive allele spread. Panama is an important hub of global trade with opportunities for Aedes introduction through both maritime and overland routes but dispersal into the Isthmus has not yet been investigated. We therefore sought to investigate the population structure and invasion history of Ae. albopictus into Panama, targeting both its mitogenome and associated Wolbachia. Historical demographic analysis with Bayesian phylogeographic diffusion models and estimates of divergence revealed that Panamanian Ae. albopictus and its associated Wolbachia have a convergent evolutionary history resulting from multiple introductions. Both could be traced to Asian-derived lineages introduced via the Americas, with invasion primarily through the maritime trade of the Panama Canal rather than overland dispersal from neighboring Costa Rica. An investigation of the relative density of Wolbachia in Panama revealed that both the strains wAlbB and wAlbA were at a notably lower density compared to other worldwide locations. This finding has implications for arbovirus transmission and raises important questions about how Wolbachia density is impacted by the environment and impacts on population control. Overall, the Panama Canal is a key route for vector introductions into Mesoamerica.
Soumaoro, L.; Coulibaly, M. E.; Diallo, A. A.; Sangare, M.; Diabate, A. F.; Coulibaly, S. Y.; Doumbia, S. S.; Koureichi, M. M.; Kone, A. K.; Dembele, K.; Dolo, H.; Yaro, A. S.; Coulibaly, Y. I.
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Entomological surveillance is essential for the control of lymphatic filariasis (LF). This xenomonitoring study, conducted in 2022-2023, evaluated the effectiveness of three mosquito trapping methods to identify the most suitable tool for surveillance following the discontinuation of mass drug administration. The surveys took place in two Malian villages: Konfra (seasonal watercourse) and Siradjouba (permanent watercourse). Three techniques were compared: Pyrethrum spray catch (PSC) conducted at the end of each visit inside 30 randomly selected houses, and different collection points were chosen based on the characteristics of the study area to place the Ifakara Type C tent (Ifakara) and the gravid trap (GT). Collections were conducted simultaneously at both sites. All Anopheles gambiae and Culex spp. collected in 2022-2023 were morphologically identified and then analyzed in the laboratory for their infectious status. Data was processed using SPSS v25; Fishers exact test was used to compare proportions, with a significance threshold of p < 0.05. A total of 4,732 mosquitoes were captured (95.05% in 2022). In 2022, the Anopheles were predominant in Konfra (91.38%), while Culex predominated in Siradjouba (63.41%). In 2023, Anopheles was found only in Konfra (3 specimens), while Culex was predominant in Siradjouba (64.07%). In 2022, PSC collected 90.57% of Anopheles, Ifakara 9.43%, and GT 0%. For Culex, GT collected 53.67%, PSC 36.62%, and Ifakara 9.71%. In 2023, the few Anopheles (3) came from PSC; Culex were mainly collected by the Ifakara tent (43.29%). For FL xenomonitoring, the combination of PSC and the GT appear to be effective collection methods.
Bamgboye, E.; Adeleke, M. A.; Surakat, O.; Mhlanga, L.; Fasasi, K.; Rufai, A. M.; Popoola, K. O.; Aminu, U. M.; Ogbulafor, N.; Ozodiegwu, I. D.
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Larval source management (LSM) is a complementary malaria control intervention, yet evidence to guide context-specific implementation remains limited. Nigeria's recent national commitment to LSM scale-up makes the need for operational evidence particularly urgent. Informal settlements embedded within wards of differing dominant settlement archetypes may present distinct Anopheles larval habitat profiles with implications for how LSM strategies should be tailored. We evaluated Anopheles larval habitats within informal settlement areas across wards with contrasting settlement archetypes in Ibadan metropolis, Nigeria, to inform targeted larval source management. Potential breeding habitats were surveyed in dry and wet seasons within informal settlement areas across three wards -- Olopomewa, Challenge, and Agugu -- representing formal, informal, and slum settlement-dominant archetypes respectively. Habitats were characterized and assessed for Anopheles larval presence. Pareto analysis identified habitats accounting for 80% of larval abundance. Breeding habitat density per km{superscript 2} was estimated using a simulated pathway technique. Associations between mosquito dispersal scale and household malaria infections identified through Rapid Diagnostic Testing were evaluated using kernel-based distance-decay weighting. Environmental drivers of habitat suitability were modeled in MaxEnt. Of 420 potential breeding habitats identified, 31 (7.4%) contained Anopheles larvae, predominantly during the wet season (26, 83.9%). Puddles, dug wells, drainages/gutters/ditches and canals accounted for 80% of site-level larval abundance when standardized by sampling effort. Larval and breeding habitat density were highest in Agugu, the slum-dominant ward, across both seasons. Modeled mosquito dispersal scale showed best fit at 30-32m in Challenge (OR 1.41, 95% CI: 1.05-1.89) during the wet season and 16-18m in Agugu (OR 1.29, 95% CI: 1.04-1.60) during the dry season. Habitat suitability in Agugu was higher farther from large water bodies and in areas with higher population density and positive Normalized Difference Water Index values. In Challenge, suitability was higher in areas with lower nighttime light levels, positive Normalized Difference Water Index values, and negative Normalized Difference Moisture Index values. Further studies incorporating multiple wards across diverse urban settings are needed to determine whether differences in larval ecology between settlement archetypes provide a reliable basis for planning larval source management.
Bhosekar, U.; Ventura, P. C.; Hill, M. D.; Kummer, A. G.; Mhade, S.; Chitturi, J.; Vasquez, C.; Mutebi, J.-P.; Townsend, J.; Litvinova, M.; Wilke, A. B. B.; Ajelli, M.
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Conventional mosquito surveillance typically relies on contemporaneous data, making it challenging to anticipate future vector surges. To support proactive vector management, this study evaluates a multi-model forecasting framework designed to generate probabilistic 1- to 4-week-ahead forecasts of Aedes aegypti relative abundance per trap night. The framework was validated using multi-year surveillance data across four US jurisdictions spanning varied environments (from subtropical to temperate and arid). We found that an ensemble approach aggregating statistical and machine learning models generally achieved the best performance across all locations and forecast horizons. Relative forecast performance improved as the forecast horizon extended from 1 to 4 weeks ahead. The most challenging data to forecast were primarily restricted to low mosquito activity periods or atypical population peaks with unusual timing or magnitude. While full integration into routine vector management workflows represents a long-term process requiring operational adaptation, this work advances forecasting research and establishes a baseline for translating these approaches into real-time applications for public health authorities, with downstream effects in mitigating the risks of mosquito-borne diseases.
Shrestha, A.; Thapa, M.; Shrestha, S.; Tamrakar, S.; Ranjitkar, U.; Katuwal, N.; Shahi, S. B.; Naga, S. R.; Andrews, J. R.; Shrestha, R.; Aiemjoy, K.; Tamrakar, D.
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Background Dengue is intensifying globally due to climate change, urbanization, and land use changes. In Nepal, dengue has expanded from lowland regions to higher altitudes, with record outbreaks in 2022 and 2023. However, reliance on passive surveillance and hospital-based studies may underestimate community level infection burden. Methods We conducted a population-based serologic cohort study in Kathmandu and Kavrepalanchok districts, Nepal, enrolling a geographically representative, age stratified random sample of residents aged 0 to 25 years from pre-defined hospital catchment areas. Enrollment occurred in two phases: Phase I (February 2019 to April 2021) with follow-up visits at approximately 3, 6, and 12 months, and Phase II (February to June 2023) revisiting the original cohort. At each household visit, we collected capillary blood samples by finger-prick onto filter paper and tested the samples for IgG responses against dengue-derived recombinant antigen using InBios DENV DetectTM ELISA. Serostatus was classified using the manufacturer's recommended immune status ratio (ISR) cutoffs. We calculated seroprevalence at each time point and estimated seroincidence rates by identifying seroconversion events per 1,000 person-years. We assessed risk factors using multivariable regression models. Results Between 2019 and 2023, we enrolled 840 participants and collected 2,082 blood samples. The overall seroincidence rate was 33.8 per 1,000 person-years (95% CI [24.9 to 45.0]), with the highest rates in urban Kathmandu ([105.7], 95% CI [75.1 to 144.4]). Seroincidence increased with age and over time from 46.1 in 2019 to 51.0 in 2023. Participants living with a dengue-positive individual in the same household (adjusted RR [4.65], 95% CI [2.72 to 8.0]) and households with water-filled flower basins (adjusted RR [2.53], 95% CI [1.28 to 5.74]) had significantly higher risk of seroconversion. Conclusions This study reveals a significant and increasing burden of dengue infection in the Kathmandu Valley between 2019 and 2023. highlighting an urgent need for immediate public health interventions to mitigate dengue's rise in Nepal's higher-altitude regions.
Aurell, D.; Tokach, R.; Chuttong, B.; Praphawilai, P.; Barascou, L.; Steury, T. D.; Duffy, K.; Jung, C.; Oh, H.; Bruckner, S.; Williams, G. R.
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A parasitic mite of honey bee brood (Tropilaelaps mercedesae), is spreading through populations of Apis mellifera honey bees in new regions and poses a major threat to honey bee health. Despite its clear threat, the biology of this mite is poorly understood, with gaps on such fundamental issues as how fast its populations can grow. This leaves the beekeeping world underprepared to plan for its arrival and management. In this study, we documented the growth of T. mercedesae populations in untreated A. mellifera colonies in Thailand and South Korea, and did the same for another parasitic mite (Varroa destructor) when possible. We found that the population growth of T. mercedesae was variable but could reach high levels (daily r of 0.010, 0.036, and 0.057), while the population growth of V. destructor (r = 0.021) matched previous estimates. Our results indicate that T. mercedesae populations can grow rapidly but they do not always attain this potential. Based on our results, humidity should be studied as a potential driver of population growth. If future work can reveal key drivers of T. mercedesae population growth, this would help predict infestations and help design management strategies that exploit the pest's biological vulnerabilities.
Ryan, S. J.; Lippi, C. J.; Johnson, L. R.; Meredith, J.
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Dengue fever risk and burden has increased globally in the past decade, with record-breaking outbreaks driving high case numbers, outbreaks increasing in existing transmission suitable regions, and occurring in new locations. A combination of global change processes, including climate change, have provided the environmental backdrop for introductions and resurgences of mosquito-transmitted dengue virus. Understanding shifts in exposure risk is integral to public health preparedness. This study provides global mapping of the thermal suitability of dengue transmission for CMIP6 climate scenarios, across a range of general circulation models (GCMs), and we created spatially explicit demographic projections of transmission risk using year-matched RCP-SSP frameworks for demographic and emissions scenarios. Globally, poleward shifts in projected distributions of suitability for transmission for both Ae. aegypti and Ae. albopictus suitability are shown in both the near term (2030s) and longer term (2050). Under a 'middle of the road' climate scenario (CMIP6 SSP2-4.5), regions in Africa and Asia are the major areas driving increases in year-round (12 months) population at risk (PAR) through 2050, with an anticipated net gain in 932 million people at risk for Ae. aegypti transmission and 24 million for Ae. albopictus, which includes multiple regions losing areas of year-round suitability as temperatures exceed the higher thermal boundary for transmission. In contrast, the estimated net increase in PAR for one or more months of transmission suitability at a global scale by 2050 is 3.29 billion people for Ae. aegypti transmission and 3.30 billion for Ae. albopictus transmission. This snapshot of a 'middle-of-the-road' combination of climate and demographic driven increases in potential dengue transmission exposure emphasizes the importance of both expanding suitability in new areas, and growing populations in areas approaching and becoming exposed year-round. Globalization, urbanization, and shipping will continue to provide the potential for introductions into newly suitable areas as season lengths increase, sparking outbreaks in unexposed populations. This is compounded and becomes ever more probable as the number of people and places at year-round risk also increases. This project provides all global gridded outputs for onward mapping and reuse, to add to the toolkit to anticipate and prepare for prevention and response to dengue in a changing world.
Mizell, R.
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Objectives identified as critical for effective management of brown marmorated stink bugs, Halyomorpha halys Stal (BMSB), were addressed in the overwintering life stage. Research was conducted on a 675-acre farm in western Maryland, U.S.A. Developing and testing were done during September - October of each of the years 2013 - 2020. Traps and related materials were developed. Four invented traps plus the development and use of "weed beater" polyethylene plastic in combination with the other traps were used as attractions to BMSB during the overwintering testing periods. Overwintering BMSB showed very little interest other than to find a place to hide that was dry, dark, easy to get into and safe over the winter months (Nielson et al. 2016). Placement of traps show effect of cardinal directions due to heat and light were north = east > west = south of numbers of BMSB. These data were affected by the vegetation, type of buildings such as silos, cabins, houses, etc., around BMSB prior to the en masse flight. Silos were used as attractants from long range during the en masse flight. Five trap types were invented and tested for use against overwintering BMSB found various places such as buildings of any type, pathways in the woods and other habitats present. Trap #1 was made of plastic out of special plant pots, turned upside down with a plastic lid and entry holes top and bottom that allowed the BMSB to reach the hexcel inside and stay there. Trap #2 was made of white, rectangular coroplast and pressed into 0.5 x 0.5 x 7.32 m (5" x 5" x 24") box also holding hexcel. Traps #1 and #2 are useful for attachment to most anything with BMSB such as the eaves in houses, other buildings, vegetation, crevasses, etc. They can be placed as horizontal or vertical with other ways that enhance efficacy. Both #1 and #2 are cheap and easy to make and use. Trap #3 is made of a cardboard tube, as a fake or "faux" tree (dead and/or dying) in vegetation 20 cm (6-8") diameter and 1.22 m (3 or 4) long. The tubes are placed on tomato stakes, have hexcel and holes made as do the others and are placed vertically in the ground. The tubes are covered with small widths of white, black and or burlap around them. Lids of plastic are on top and the trap appears as a dead and/or dying tree. The fourth trap is a "mechanism" or resembling some kind of "Haven" if you will, made of "weed beater" plastic materials 1.98 m (66") wide in brown or black. The materials are placed on trees by wrapping them around 3-4 trees near 4.6 m (10-15 long). Traps 1 and 2 can then be placed on the outside of the plastic walls and the #3 fake trees can be added around the outside areas. Around 60,000 BMSB were collected and counted in these experiments by the author, and several different factors were raised and addressed to better understand the BMSB behavior during the overwintering stage. The results provide several new tools as well as understanding of approaches to address BMSB management better.
Ndenga, B. A.; Agola, G. A.; Owuor, K. O.; Mbakaya, J. O.; Ronga, C. O.; Chepkorir, E.; Kibe, L. W.; Akala, H. M.
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Introduction Malaria is a global public health problem especially in sub Saharan Africa. In Kenya, it varies across ecological zones with limited evidence comparing vector ecology, climate, topography and risk of infection in western lowlands and central highlands. Objective To compare levels of malaria infection, vector densities, rainfall, temperature, relative humidity and topography in lowland Busia and highland Meru counties. Methods A cross sectional survey was conducted using larval dipping for aquatic habitats, pyrethrum spray catches for indoor resting mosquitoes, and malaria diagnosis using rapid diagnostic tests and microscopy. Rainfall, temperature, and relative humidity were recorded using automated data loggers. Topography was noted by ground truthing. Data were analysed using chi square tests, analysis of variance, and logistic regression. Results Early instar Anopheles larvae were significantly less likely to be detected in the highland site than in the lowland site (unadjusted Odds Ratio = 0.33; 95% CI: 0.11 - 0.97). Malaria prevalence by rapid diagnostic tests was 0% in the highland site and significantly higher in lowland sites (p < 0.001), with microscopy confirming the absence of infections in the highland area. Highland sites experienced significantly cooler temperatures, including more hours below 16 degrees Celsius (p = 0.006), whereas lowland sites recorded significantly higher minimum, mean, and maximum temperatures (p < 0.001). Rainfall did not differ significantly between the two ecological zones (p = 0.090), average minimum RH in the highland was significantly higher than in the lowland site (p < 0.001). Valleys in Baragu are mainly V-shaped while Maduwa and Budalangi are generally flat areas in the lower courses of rivers prone to flooding. Conclusion Cooler highland climates and topographic features likely limit vector presence, abundance, development and malaria transmission, while warmer lowland environments sustain residual transmission.
Rolfi, J.; Radici, A.; Bandi, C.; Epis, S.; Gabrieli, P.; Brilli, M.
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The mosquito Aedes albopictus is a competent vector for the transmission of several arboviruses and is currently spreading across many continents. Since conventional control methods, like insecticides, often lead to environmental problems and the emergence of resistance, scientists developed alternative mosquito control strategies. One of the most used is the Sterile Insect Technique (SIT), which involves the mass release of males sterilized through irradiation. The Toxic Male Technique (TMT) is instead based on the release of genetically modified males expressing toxic proteins that kill females when they mate. Control strategies are often intended as methods to eradicate mosquito populations, yet a less ambitious and more cost-effective task is to reduce them such that the probability of transmission of viruses to humans becomes negligible. To compare the efficacy of these control strategies, we develop a mathematical model with two communicating compartments: a mosquito population and epidemiological model coupled with a human epidemiological model. As a proof-of-concept, we test the model using meteorological and entomological data for the Emilia-Romagna region. Our results indicate that the TMT strategy is more effective in lowering the probability of transmission and provides indication for the deployment of control strategies.
Klöcklerova, V.; Koci, J.; Buchova, E.; Medla, M.; Slovak, M.; Roller, L.; Zitnan, D.
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The tick Ixodes ricinus is the main vector of human and animal pathogens in Europe. Despite its importance in epidemiology and medicine, our understanding of physiological mechanisms controlling blood feeding, osmoregulation, or development are still limited. Here, we identify novel neuropeptide invertebrate parathyroid hormone-like peptide (iPTH) and its two receptors - PTHR1 and PTHR2 in I. ricinus. Functional aequorin-based assay confirmed specific activation of both receptors by iPTH. Using RT-qPCR we detected the PTHR1 transcript in the synganglion, while increased expression levels of PTHR2 were found in the salivary glands, hindgut and female gonads. RNA-mediated knockdown of iPTH receptors in nymphs resulted in delayed blood feeding, and a high incidence of defects in adult ecdysis. Consistent with observed phenotypes, iPTH is expressed in multiple neurons of the synganglion which project arborizing axons to the salivary glands, rectal sack and skeletal muscles. iPTH was colocalized with orcokinin-immunoreactivity (OK-IR) in all neurons that innervate these peripheral tissues. iPTH is further colocalized with tachykinin (TK) in Pd1DL1 neurons, suggesting coordinated action with other neuropeptides. Our findings indicate that iPTH signaling is required for normal feeding, development and successful ecdysis.
Xavier, J. P. d. O.; Almeida-Silva, D.; Marcili, A.; Speranca, M. A.; Jordao, F. T.; Cabral, A. D.; Verdade, V. K.
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While emerging diseases pose a global threat to amphibians, the dynamics of understudied vector-borne blood pathogens remain poorly understood. Pathogen occurrence is driven by a combination of environmental, ecological, and phylogenetic factors, yet how these drivers shape blood pathogen communities in tropical amphibians is largely unknown. In this study, we used molecular screening and phylogenetic linear models (PGLMMs) to evaluate how climate and ecomorphology influence the incidence of three blood pathogen groups (Trypanosomatidae, Hepatozoon, and Rickettsia) in wild anurans from a protected area in the Brazilian Atlantic Forest. Among 93 individuals sampled, over 93% were infected with at least one pathogen. Trypanosomatidae was the most common (76.3%), followed by Rickettsia (69.9%) and Hepatozoon (16.1%). Pathogen responses to temperature were contrasting: Hepatozoon occurrence increased in warmer periods, while Trypanosomatidae declined. Furthermore, rheophilic species showed a lower probability of Rickettsia infection, providing the first evidence that microhabitat use influences blood pathogen dynamics in amphibians. Our findings demonstrate that hemoparasites prevalence is driven by a multifaceted interplay of variables, highlighting that conservation strategies must account for these pathogen-specific responses to habitat use and environmental change, even within protected areas.
Dimitrov, N.; Gelmi-Candusso, T. A.; Krkosek, M.; Fortin, M.-J.
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ContextThe movement of vertebrate hosts across urbanized landscapes can play a key role in the transmission of direct-contact diseases. Understanding how wildlife hosts move in urban landscapes, and how transmission is affected by their landscape-constrained and disease-altered movements, is imperative for better predicting the spread of disease. ObjectiveWe assess how the movement of red foxes (Vulpes vulpes) according to landcover type, and their infection status, affect the spread of mange (caused by Sarcoptes scabiei) in an urbanized landscape. MethodsWe developed a mange transmission model (MTM) using an agent-based model to compare two movement behaviours of foxes in Scarborough (Ontario, Canada): random and landcover-based. We further assessed the effects of movement on disease transmission by considering the foxs infection status and comparing a range of movement probability scenarios. We quantified the number of effective contact events and the effective reproduction number (Re) according to each scenario. ResultsWe found that both landcover-dependent movement and infection status influenced the spread of mange within fox populations. The number of effective contact events and effective reproduction number Re was greatest when landscape heterogeneity was included in the model and foxes moved through paths of least resistance to movement, and when susceptible and infected foxes had an equal probability of leaving a fragmented habitat patch. ConclusionsOur findings suggest that mange spread may be accelerated along movement corridors in fragmented, heterogenous landscapes. As urban areas expand and remnant habitat within these is further lost and animals are relegated to fewer movement pathways, disease transmission may increase.
Mizell, R. F.
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Xylosandrus crassiusculus (Motschulsky), the granulate ambrosia beetle, was one of the first highly-destructive ambrosia beetles introduced into the southern U.S in the 1970s where it was found in South Carolina (Kovach 1986). The Redbay ambrosia beetle, Xyleborus glabratus Eichhoff, was first detected in the U.S. in South Georgia in 2002. This beetle and its associated fungi, the laurel wilt fungus Raffaelea laurelensis and others have caused substantial destruction to native redbay (Persea borbonia) in GA, SC, FL and elsewhere. This beetle-pathogen complex also poses a threat to commercial avocado production in the U.S., Central and South America as well as to valuable other Persea spp. and related plants (Laureacea) that are known hosts. As an addition here, 10 years of the spring appearances (Fig.1) of X. crassiusculus in North Florida is offered for future comparisons. A second unusual appearance is the finding and working with UV mulch and ethanol, as a surprising attraction of X. crassiusculus and other ambrosia beetles including X. glabratus. It was also found that the ambrosia beetles do not respond to yellow and green as expected by most. Also, adding burlap was found to be attractive (increases dead and dying appearing trees) as is silver metallic like UV mulch, while camouflage (camo) was found to work like yellow and green. These occurrences led to the invention and development of UV mulch with new traps to better monitor ambrosia beetles. New traps led to new uses for yellow, green and camo to monitor and decrease damage and losses from ambrosia beetles. The data are presented as evaluated and appear in the figures, discussion and a supplemental section. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=139 SRC="FIGDIR/small/733798v1_fig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@1006101org.highwire.dtl.DTLVardef@1e0a3d6org.highwire.dtl.DTLVardef@1244d1borg.highwire.dtl.DTLVardef@423cb7_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 1:C_FLOATNO Relative timing of annual emergence of Xylosandrus crassiusculus in north Florida. Collected over 10 years using 5 Baker traps with a 10% ethanol/water solution. Data are from years as marked. Note: data from year 2003 was not collected. C_FIG
Csivincsik, A.; Nagy, E.; Zam, I.; Tari, T.; Kucsera, I.; Nagy, G.; Sreter, T.
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Background: Dirofilaria repens is a zoonotic parasite expanding unnoticed across Europe due to climate change. We hypothesised that in this process, the Carpathian Basin has a facilitating effect. Methods: Using 426 georeferenced European cases, the probability of infection occurrence was determined in relation to climatic factors, surface water availability, regional social deprivation, and stray dog population density. To analyse the potential impacts of ecological and social factors (deprivation and stray dog population density), the MaxEnt algorithm, and spatial Empirical Bayes smoothing and Bivariate Local Indicators of Spatial Association (BiLISA) index calculation were employed, respectively. Results: MaxEnt analysis revealed that the mean warmest month temperature (22.8 - 25.1 oC), winter mean minimum temperature (> -2.1 oC), and summer precipitation (28.6 - 231 mm) have the strongest impact on the probability of the parasite's occurrence in Europe. Social factors have significance in the eastern Balkans and the Carpathian Basin, but not in Western Europe. The Carpathian Basin appears to be a hotspot, similar to Mediterranean coastal areas. Furthermore, the Danube Valley acts as an ecological corridor for subtropical vector-borne parasites. Conclusions: Our findings confirm that summer warmth is the primary ecological driver of the parasite's range expansion, which is facilitated by the Carpathian Basin due to climatic and socioeconomic conditions.
Madgaonkar, S. R.; Vashishth, S.; Ayyanar, E.; Srirama, S.; Samal, A.
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Ticks transmit pathogens across wildlife, domestic animals, and humans, and are therefore considered important vectors under the One Health framework. In India, the burden of tick-borne diseases, such as Kyasanur Forest Disease and Crimean-Congo Hemorrhagic Fever, remains poorly quantified due to fragmented surveillance and limited spatial data. Here, we present TickMapKB, a curated spatial knowledgebase documenting 72 tick species across more than 600 georeferenced locations in India. The majority of the species belonged to the genera Haemaphysalis, Rhipicephalus, and Hyalomma. Additionally, the resource integrates host associations, pathogen and disease information, morphological identification keys, acaricide resistance profiles, and protein annotations into a single, interactive platform accessible at https://cb.imsc.res.in/tickmapkb/. Specifically, the resource captures 53 pathogens, over 3000 protein annotations, and morphological keys from 26 published resources. TickMapKB thus provides researchers, clinicians, and other stakeholders with integrated spatial, biological, and resistance information to support surveillance planning, resistance management, and tick-borne disease risk assessment.