Data release: targeted systematic literature search for tick and tick-borne pathogen distributions in six countries in sub-Saharan Africa from 1901 to 2020.

BACKGROUND: Surveillance data documenting tick and tick-borne disease (TBD) prevalence is needed to develop risk assessments and implement control strategies. Despite extensive research in Africa, there is no standardized, comprehensive review. METHODS: Here we tackle this knowledge gap, by producing a comprehensive review of research articles on ticks and TBD between 1901 and 2020 in Chad, Djibouti, Ethiopia, Kenya, Tanzania, and Uganda. Over 8356 English language articles were recovered. Our search strategy included 19 related MeSH terms. Articles were reviewed, and 331 met inclusion criteria. Articles containing mappable data were compiled into a standardized data schema, georeferenced, and uploaded to VectorMap. RESULTS: Tick and pathogen matrixes were created, providing information on vector distributions and tick-pathogen associations within the six selected African countries. CONCLUSIONS: These results provide a digital, mappable database of current and historical tick and TBD distributions across six countries in Africa, which can inform specific risk modeling, determine surveillance gaps, and guide future surveillance priorities.

Understanding transmission risk and predicting environmental suitability for Mayaro Virus in Central and South America.

Mayaro virus (MAYV) is a mosquito-borne Alphavirus that is widespread in South America. MAYV infection often presents with non-specific febrile symptoms but may progress to debilitating chronic arthritis or arthralgia. Despite the pandemic threat of MAYV, its true distribution remains unknown. The objective of this study was to clarify the geographic distribution of MAYV using an established risk mapping framework. This consisted of generating evidence consensus scores for MAYV presence, modeling the potential distribution of MAYV in select countries across Central and South America, and estimating the population residing in areas suitable for MAYV transmission. We compiled a georeferenced compendium of MAYV occurrence in humans, animals, and arthropods. Based on an established evidence consensus framework, we integrated multiple information sources to assess the total evidence supporting ongoing transmission of MAYV within each country in our study region. We then developed high resolution maps of the disease's estimated distribution using a boosted regression tree approach. Models were developed using nine climatic and environmental covariates that are related to the MAYV transmission cycle. Using the output of our boosted regression tree models, we estimated the total population living in regions suitable for MAYV transmission. The evidence consensus scores revealed high or very high evidence of MAYV transmission in several countries including Brazil (especially the states of Mato Grosso and Goiás), Venezuela, Peru, Trinidad and Tobago, and French Guiana. According to the boosted regression tree models, a substantial region of South America is suitable for MAYV transmission, including north and central Brazil, French Guiana, and Suriname. Some regions (e.g., Guyana) with only moderate evidence of known transmission were identified as highly suitable for MAYV. We estimate that approximately 58.9 million people (95% CI: 21.4-100.4) in Central and South America live in areas that may be suitable for MAYV transmission, including 46.2 million people (95% CI: 17.6-68.9) in Brazil. Our results may assist in prioritizing high-risk areas for vector control, human disease surveillance and ecological studies.

Haemagogus equinus in Kinney County, Texas.

Larvae collected from an oak tree hole east of Brackettville, Kinney County, Texas, resulted in the collection of 3 species: Aedes triseriatus, Ae. zoosophus, and Haemagogus equinus. One larva and 1 female of Hg. equinus were recovered from this sample. This is the first report of Hg. equinus in Kinney County and the first report of this species being collected in Texas since 1962. Samples collected from other sites documented the presence of Ae. epactius, Culex nigripalpus, and Psorophora signipennis in Kinney County.

High Levels of Diversity in Anopheles Subgenus Kerteszia Revealed by Species Delimitation Analyses.

The Anopheles subgenus Kerteszia is a poorly understood group of mosquitoes that includes several species of medical importance. Although there are currently twelve recognized species in the subgenus, previous studies have shown that this is likely to be an underestimate of species diversity. Here, we undertake a baseline study of species delimitation using the barcode region of the mtDNA COI gene to explore species diversity among a geographically and taxonomically diverse range of Kerteszia specimens. Beginning with 10 of 12 morphologically identified Kerteszia species spanning eight countries, species delimitation analyses indicated a high degree of cryptic diversity. Overall, our analyses found support for at least 28 species clusters within the subgenus Kerteszia. The most diverse taxon was Anopheles neivai, a known malaria vector, with eight species clusters. Five other species taxa showed strong signatures of species complex structure, among them Anopheles bellator, which is also considered a malaria vector. There was some evidence for species structure within An. homunculus, although the results were equivocal across delimitation analyses. The current study, therefore, suggests that species diversity within the subgenus Kerteszia has been grossly underestimated. Further work will be required to build on this molecular characterization of species diversity and will rely on genomic level approaches and additional morphological data to test these species hypotheses.

Crimean-Congo hemorrhagic fever virus in Central, Eastern, and South-eastern Asia.

Crimean-Congo hemorrhagic fever (CCHF), caused by Crimean-Congo hemorrhagic fever virus (CCHFV), is endemic in Africa, Asia, and Europe, but CCHF epidemiology and epizootiology is only rudimentarily defined for most regions. Here we summarize what is known about CCHF in Central, Eastern, and South-eastern Asia. Searching multiple international and country-specific databases using a One Health approach, we defined disease risk and burden through identification of CCHF cases, anti-CCHFV antibody prevalence, and CCHFV isolation from vector ticks. We identified 2313 CCHF cases that occurred in 1944-2021 in the three examined regions. Central Asian countries reported the majority of cases (2,026). In Eastern Asia, China was the only country that reported CCHF cases (287). In South-eastern Asia, no cases were reported. Next, we leveraged our previously established classification scheme to assign countries to five CCHF evidence levels. Six countries (China, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan) were assigned to level 1 or level 2 based on CCHF case reports and the maturity of the countries' surveillance systems. Two countries (Mongolia and Myanmar) were assigned to level 3 due to evidence of CCHFV circulation in the absence of reported CCHF cases. Thirteen countries in Eastern and South-eastern Asia were categorized in levels 4 and 5 based on prevalence of CCHFV vector ticks. Collectively, this paper describes the past and present status of CCHF reporting to inform international and local public-health agencies to strengthen or establish CCHFV surveillance systems and address shortcomings.

Global Distribution of Aedes aegypti and Aedes albopictus in a Climate Change Scenario of Regional Rivalry.

Arboviral mosquito vectors are key targets for the surveillance and control of vector-borne diseases worldwide. In recent years, changes to the global distributions of these species have been a major research focus, aimed at predicting outbreaks of arboviral diseases. In this study, we analyzed a global scenario of climate change under regional rivalry to predict changes to these species' distributions over the next century. Using occurrence data from VectorMap and environmental variables (temperature and precipitation) from WorldClim v. 2.1, we first built fundamental niche models for both species with the boosted regression tree modelling approach. A scenario of climate change on their fundamental niche was then analyzed. The shared socioeconomic pathway scenario 3 (regional rivalry) and the global climate model Geophysical Fluid Dynamics Laboratory Earth System Model v. 4.1 (GFDL-ESM4.1; gfdl.noaa.gov) were utilized for all analyses, in the following time periods: 2021-2040, 2041-2060, 2061-2080, and 2081-2100. Outcomes from these analyses showed that future climate change will affect Ae. aegypti and Ae. albopictus distributions in different ways across the globe. The Northern Hemisphere will have extended Ae. aegypti and Ae. albopictus distributions in future climate change scenarios, whereas the Southern Hemisphere will have the opposite outcomes. Europe will become more suitable for both species and their related vector-borne diseases. Loss of suitability in the Brazilian Amazon region further indicated that this tropical rainforest biome will have lower levels of precipitation to support these species in the future. Our models provide possible future scenarios to help identify locations for resource allocation and surveillance efforts before a significant threat to human health emerges.

Redescription of Leptoconops (Leptoconops) brasiliensis (Lutz) and Leptoconops (Megaconops) floridensis Wirth (Diptera: Ceratopogonidae) with its first Brazilian record.

The Leptoconops Skuse genus includes many pestiferous biting midges found in coastal areas. Only two species were previously found in Brazil and some species have ancient descriptions lacking updated taxonomic features. Herein, we redescribe Leptoconops (Leptoconops) brasiliensis Lutz and L. (Megaconops) floridensis Wirth based on female type specimens and additional material from Gois and Santa Catarina, Brazil. The first Brazilian record of L. (M.) floridensis is reported.

Phylogenetic analysis of the Neotropical Albitarsis Complex based on mitogenome data.

BACKGROUND: Some of the most important malaria vectors in South America belong to the Albitarsis Complex (Culicidae; Anophelinae; Anopheles). Understanding the origin, nature, and geographical distribution of species diversity in this important complex has important implications for vector incrimination, control, and management, and for modelling future responses to climate change, deforestation, and human population expansion. This study attempts to further explore species diversity and evolutionary history in the Albitarsis Complex by undertaking a characterization and phylogenetic analysis of the mitogenome of all 10 putative taxa in the Albitarsis Complex. METHODS: Mitogenome assembly and annotation allowed for feature comparison among Albitarsis Complex and Anopheles species. Selection analysis was conducted across all 13 protein-coding genes. Maximum likelihood and Bayesian inference methods were used to construct gene and species trees, respectively. Bayesian methods were also used to jointly estimate species delimitation and species trees. RESULTS: Gene composition and order were conserved across species within the complex. Unique signatures of positive selection were detected in two species-Anopheles janconnae and An. albitarsis G-which may have played a role in the recent and rapid diversification of the complex. The COI gene phylogeny does not fully recover the mitogenome phylogeny, and a multispecies coalescent-based phylogeny shows that considerable uncertainty exists through much of the mitogenome species tree. The origin of divergence in the complex dates to the Pliocene/Pleistocene boundary, and divergence within the distinct northern South American clade is estimated at approximately 1 million years ago. Neither the phylogenetic trees nor the delimitation approach rejected the 10-species hypothesis, although the analyses could not exclude the possibility that four putative species with scant a priori support (An. albitarsis G, An. albitarsis H, An. albitarsis I, and An. albitarsis J), represent population-level, rather than species-level, splits. CONCLUSION: The lack of resolution in much of the species tree and the limitations of the delimitation analysis warrant future studies on the complex using genome-wide data and the inclusion of additional specimens, particularly from two putative species, An. albitarsis I and An. albitarsis J.

Mosquito species identification using convolutional neural networks with a multitiered ensemble model for novel species detection.

With over 3500 mosquito species described, accurate species identification of the few implicated in disease transmission is critical to mosquito borne disease mitigation. Yet this task is hindered by limited global taxonomic expertise and specimen damage consistent across common capture methods. Convolutional neural networks (CNNs) are promising with limited sets of species, but image database requirements restrict practical implementation. Using an image database of 2696 specimens from 67 mosquito species, we address the practical open-set problem with a detection algorithm for novel species. Closed-set classification of 16 known species achieved 97.04 ± 0.87% accuracy independently, and 89.07 ± 5.58% when cascaded with novelty detection. Closed-set classification of 39 species produces a macro F1-score of 86.07 ± 1.81%. This demonstrates an accurate, scalable, and practical computer vision solution to identify wild-caught mosquitoes for implementation in biosurveillance and targeted vector control programs, without the need for extensive image database development for each new target region.

Epidemiology of Crimean-Congo Hemorrhagic Fever (CCHF) in Africa-Underestimated for Decades.

Crimean-Congo hemorrhagic fever (CCHF) is endemic in Africa, but the epidemiology remains to be defined. Using a broad database search, we reviewed the literature to better define CCHF evidence in Africa. We used a One Health approach to define the impact of CCHF by reviewing case reports, human and animal serology, and records of CCHF virus (CCHFV) isolations (1956-mid-2020). In addition, published and unpublished collection data were used to estimate the geographic distribution of Hyalomma ticks and infection vectors. We implemented a previously proposed classification scheme for organizing countries into five categories by the level of evidence. From January 1, 1956 to July 25, 2020, 494 CCHF cases (115 lethal) were reported in Africa. Since 2000, nine countries (Kenya, Mali, Mozambique, Nigeria, Senegal, Sierra Leone, South Sudan, Sudan, and Tunisia) have reported their first CCHF cases. Nineteen countries reported CCHF cases and were assigned level 1 or level 2 based on maturity of their surveillance system. Thirty countries with evidence of CCHFV circulation in the absence of CCHF cases were assigned level 3 or level 4. Twelve countries for which no data were available were assigned level 5. The goal of this review is to inform international organizations, local governments, and healthcare professionals about shortcomings in CCHF surveillance in Africa to assist in a movement toward strengthening policy to improve CCHF surveillance.

From e-voucher to genomic data: Preserving archive specimens as demonstrated with medically important mosquitoes (Diptera: Culicidae) and kissing bugs (Hemiptera: Reduviidae).

Scientific collections such as the U.S. National Museum (USNM) are critical to filling knowledge gaps in molecular systematics studies. The global taxonomic impediment has resulted in a reduction of expert taxonomists generating new collections of rare or understudied taxa and these large historic collections may be the only reliable source of material for some taxa. Integrated systematics studies using both morphological examinations and DNA sequencing are often required for resolving many taxonomic issues but as DNA methods often require partial or complete destruction of a sample, there are many factors to consider before implementing destructive sampling of specimens within scientific collections. We present a methodology for the use of archive specimens that includes two crucial phases: 1) thoroughly documenting specimens destined for destructive sampling-a process called electronic vouchering, and 2) the pipeline used for whole genome sequencing of archived specimens, from extraction of genomic DNA to assembly of putative genomes with basic annotation. The process is presented for eleven specimens from two different insect subfamilies of medical importance to humans: Anophelinae (Diptera: Culicidae)-mosquitoes and Triatominae (Hemiptera: Reduviidae)-kissing bugs. Assembly of whole mitochondrial genome sequences of all 11 specimens along with the results of an ortholog search and BLAST against the NCBI nucleotide database are also presented.

Incursion and establishment of the Old World arbovirus vector Aedes (Fredwardsius) vittatus (Bigot, 1861) in the Americas.

Routine biosurveillance efforts at the Naval Station Guantanamo Bay, Cuba, on 18 June 2019, detected two unusual mosquitos in a CO2-baited CDC light trap. Morphological and molecular analysis confirmed the presence of Aedes (Fredwardsius) vittatus (Bigot, 1861) - the first record of the Old World dengue, chikungunya, Zika and yellow fever virus vector into the Americas - and provides evidence for its establishment in Cuba. Newly submitted GenBank sequences from Dominican Republic further evidence its establishment in the Caribbean, and a median-joining network analysis using mitochondrial COI gene sequences clearly supports multiple introductions of Ae. vittatus into the Caribbean from the Indian subcontinent. It was determined that many Ae. vittatus COI barcode sequences in GenBank are currently misidentified as Aedes (Fredwardsius) cogilli Edwards, 1922.

An Emerging Biothreat: Crimean-Congo Hemorrhagic Fever Virus in Southern and Western Asia.

Tick-borne Crimean-Congo hemorrhagic fever virus (CCHFV) is endemic in numerous countries, but the epidemiology and epizoology of Crimean-Congo hemorrhagic fever (CCHF) remain to be defined for most regions of the world. Using a broad database search approach, we reviewed the literature on CCHF and CCHFV in Southern and Western Asia to better define the disease burden in these areas. We used a One Health approach, moving beyond a focus solely on human disease burden to more comprehensively define this burden by reviewing CCHF case reports, human and animal CCHFV seroprevalence studies, and human and animal CCHFV isolations. In addition, we used published literature to estimate the distribution of Hyalomma ticks and infection of these ticks by CCHFV. Using these data, we propose a new classification scheme for organizing the evaluated countries into five categories by level of evidence for CCHF endemicity. Twelve countries have reported CCHF cases, five from Southern Asia and seven from Western Asia. These were assigned to level 1 or 2. Eleven countries that have evidence of vector circulation but did not report confirmed CCHF cases were assigned to level 3 or 4. This classification scheme was developed to inform policy toward strengthening CCHF disease surveillance in the Southern and Western Asia regions. In particular, the goal of this review was to inform international organizations, local governments, and health-care professionals about current shortcomings in CCHFV surveillance in these two high-prevalence regions.

An Excel Spreadsheet Tool for Exploring the Seasonality of Aedes Vector Hazard for User-Specified Administrative Regions of Brazil.

Aedes-vectored viruses are a major concern for active-duty military personnel working in South and Central America at certain times of the year. Knowledge about the seasonal changes of vector activity is important as it informs time-sensitive vector control, prophylaxis, and travel decisions. To assist in-country and extralimital efforts to anticipate when vector hazards and the risks of transmission are highest, we developed an Excel spreadsheet tool that uses published monthly habitat suitability models to display various aspects of average Aedes seasonality for user-defined second order administrative areas of Brazil. This tool expands on those previously developed by the authors for the contiguous United States, with the aim of translating global habitat suitability models into user-friendly formats to provide actionable intelligence for areas of interest.

Mosquito Surveillance Conducted by US Military Personnel in the Aftermath of the Nuclear Explosion at Nagasaki, Japan, 1945.

Mosquito surveillance data can be used to develop bionomic profiles of vector species to inform abatement plans. Thus, surveillance was conducted in the months following Allied occupation of Japan at the conclusion of World War II. Mosquito surveillance in Nagasaki, Japan, began one month after the nuclear bomb destroyed much of the city. The resulting specimens housed within the US National mosquito collection are documented here for the first time. Specimen labels were digitized and specimens were photographed to record specimen condition as part of the process for making them readily available to researchers.

A location-specific spreadsheet for estimating Zika risk and timing for Zika vector surveillance, using US military facilities as an example.

Local Zika virus transmission in the United States involving one or both of the known vector species, Aedes aegypti and Ae. albopictus, is of major concern. To assist efforts to anticipate the risks of transmission, we developed an Excel spreadsheet tool that uses vector and virus temperature thresholds, remotely sensed maximum temperature, and habitat suitability models to answer the questions: "is Zika transmission likely here?" and "when should we conduct vector surveillance?" An example spreadsheet, updated regularly and freely available, uses near real-time and forecast temperature data to generate guidance, based on a novel four level Zika risk code, for 733 US military facilities in the 50 states, the District of Columbia, and the territories of Guam and Puerto Rico.

SandflyMap: leveraging spatial data on sand fly vector distribution for disease risk assessments.

We feature SandflyMap (www.sandflymap.org), a new map service within VectorMap (www.vectormap.org) that allows free public online access to global sand fly, tick and mosquito collection records and habitat suitability models. Given the short home range of sand flies, combining remote sensing and collection point data give a powerful insight into the environmental determinants of sand fly distribution. SandflyMap is aimed at medical entomologists, vector disease control workers, public health officials and health planners. Data are checked for geographical and taxonomic errors, and are comprised of vouchered specimen information, and both published and unpublished observation data. SandflyMap uses Microsoft Silverlight and ESRI's ArcGIS Server 10 software platform to present disease vector data and relevant remote sensing layers in an online geographical information system format. Users can view the locations of past vector collections and the results of models that predict the geographic extent of individual species. Collection records are searchable and downloadable, and Excel collection forms with drop down lists, and Excel charts to country, are available for data contributors to map and quality control their data. SandflyMap makes accessible, and adds value to, the results of past sand fly collecting efforts. We detail the workflow for entering occurrence data from the literature to SandflyMap, using an example for sand flies from South America. We discuss the utility of SandflyMap as a focal point to increase collaboration and to explore the nexus between geography and vector-borne disease transmission.