The Threat of Vector-Borne Diseases in Sierra Leone.

Sierra Leone is vulnerable to a wide range of vector-borne diseases transmitted by mosquitoes, tsetse flies, black flies, and other vectors. Malaria, lymphatic filariasis, and onchocerciasis have posed the greatest threat and have received the most attention in terms of vector control and capacity for diagnosis. However, malaria infection rates remain high, and there is evidence of circulation of other vector-borne diseases, such as chikungunya and dengue, which may go undiagnosed and unreported. The limited understanding of the prevalence and transmission of these diseases restricts the capacity for predicting outbreaks, and impedes the planning of appropriate responses. We review the available literature and gather expert opinions from those working in the country to report on the status of vector-borne disease transmission and control in Sierra Leone, and present an assessment of the threats of these diseases. Our discussions highlight an absence of entomological testing for disease agents and the need for more investment in surveillance and capacity strengthening.

Multi-Year Comparison of Community- and Species-Level West Nile Virus Antibody Prevalence in Birds from Atlanta, Georgia and Chicago, Illinois, 2005-2016.

West Nile virus (WNV) is prevalent in the United States but shows considerable variation in transmission intensity. The purpose of this study was to compare patterns of WNV seroprevalence in avian communities sampled in Atlanta, Georgia and Chicago, Illinois during a 12-year period (Atlanta 2010-2016; Chicago 2005-2012) to reveal regional patterns of zoonotic activity of WNV. WNV antibodies were measured in wild bird sera using ELISA and serum neutralization methods, and seroprevalence among species, year, and location of sampling within each city were compared using binomial-distributed generalized linear mixed-effects models. Seroprevalence was highest in year-round and summer-resident species compared with migrants regardless of region; species explained more variance in seroprevalence within each city. Northern cardinals were the species most likely to test positive for WNV in each city, whereas all other species, on average, tested positive for WNV in proportion to their sample size. Despite similar patterns of seroprevalence among species, overall seroprevalence was higher in Atlanta (13.7%) than in Chicago (5%). Location and year of sampling had minor effects, with location explaining more variation in Atlanta and year explaining more variation in Chicago. Our findings highlight the nature and magnitude of regional differences in WNV urban ecology.

The Impact of Callous-Unemotional Traits on Achievement, Behaviors, and Relationships in School: A Systematic Review.

Disruptive behavior disorders (DBDs) are associated with significant academic, behavioral, and relationship challenges in the school setting. Children with co-occurring DBDs and callous-unemotional (CU) traits show a distinct pattern of early starting, chronic, and aggressive disruptive behavior and are resistant to traditional DBD interventions. There is growing evidence that CU traits have important consequences for children's school functioning. The purpose of this systematic review is to synthesize research on CU traits in school with a focus on academics, relationships, and behavior. We searched PsycINFO, PubMed, and Education Full-Text to identify 37 empirical studies that met inclusionary criteria. Findings suggest that CU traits are associated with poor academic performance, high levels of aggression and conduct problems, and difficulty forming relationships at school, often above and beyond the impact of DBDs alone. Findings and future directions are discussed including how the current study can support key stakeholders in promoting the success of students with elevated CU traits.

Recent Increase in COVID-19 Cases Reported Among Adults Aged 18-22 Years - United States, May 31-September 5, 2020.

Although children and young adults are reportedly at lower risk for severe disease and death from infection with SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), than are persons in other age groups (1), younger persons can experience infection and subsequently transmit infection to those at higher risk for severe illness (2-4). Although at lower risk for severe disease, some young adults experience serious illness, and asymptomatic or mild cases can result in sequelae such as myocardial inflammation (5). In the United States, approximately 45% of persons aged 18-22 years were enrolled in colleges and universities in 2019 (6). As these institutions reopen, opportunities for infection increase; therefore, mitigation efforts and monitoring reports of COVID-19 cases among young adults are important. During August 2-September 5, weekly incidence of COVID-19 among persons aged 18-22 years rose by 55.1% nationally; across U.S. Census regions,* increases were greatest in the Northeast, where incidence increased 144.0%, and Midwest, where incidence increased 123.4%. During the same period, changes in testing volume for SARS-CoV-2 in this age group ranged from a 6.2% decline in the West to a 170.6% increase in the Northeast. In addition, the proportion of cases in this age group among non-Hispanic White (White) persons increased from 33.8% to 77.3% during May 31-September 5. Mitigation and preventive measures targeted to young adults can likely reduce SARS-CoV-2 transmission among their contacts and communities. As colleges and universities resume operations, taking steps to prevent the spread of COVID-19 among young adults is critical (7).

Enhanced vector surveillance to control arbovirus epidemics in Colombia.

In the wake of the Zika epidemic, there has been intensified interest in the surveillance and control of the arbovirus vectors Aedes aegypti and Aedes albopictus, yet many existing surveillance systems could benefit from improvements. Vector control programs are often directed by national governments, but are carried out at the local level, resulting in the discounting of spatial heterogeneities in ecology and epidemiology. Furthermore, entomological and epidemiological data are often collected by separate governmental entities, which can slow vector control responses to outbreaks. Colombia has adopted several approaches to address these issues. First, a web-based, georeferenced Aedes surveillance system called SIVIEN AEDES was developed to allow field entomologists to record vector abundance and insecticide resistance data. Second, autocidal gravid oviposition (AGO) traps are deployed as an alternative way to measure vector abundance. Third, data collected by SIVIEN AEDES are used to develop mathematical models predicting Ae. aegypti abundance down to a city block, thus allowing public health authorities to target interventions to specific neighborhoods within cities. Finally, insecticide resistance is monitored through bioassays and molecular testing in 15 high-priority cities, providing a comprehensive basis to inform decisions about insecticide use in different regions. The next step will be to synchronize SIVIEN AEDES data together with epidemiological and climatic data to improve the understanding of the drivers of local variations in arbovirus transmission dynamics. By integrating these surveillance data, health authorities will be better equipped to develop tailored and timely solutions to control and prevent Aedes-borne arbovirus outbreaks.

Tras la epidemia del Zika, se ha intensificado el interés en vigilar y controlar los vectores de arbovirus Aedes aegypti y Aedes albopictus. Aun así, muchos de los sistemas existentes de vigilancia necesitan mejorar. En general son los gobiernos nacionales los que dirigen los programas de control de vectores, aunque estos programas se llevan a cabo a nivel local, por lo que no se tiene en cuenta la heterogeneidad del lugar en cuanto a las características ecológicas y epidemiológicas. Además, normalmente los datos entomológicos y epidemiológicos son recopilados por entidades gubernamentales distintas, lo que puede ralentizar el control de vectores durante un brote. Colombia ha puesto en marcha varias iniciativas para abordar estas cuestiones. La primera es un sistema en línea de geolocación del mosquito Aedes, llamado SIVIEN AEDES, para que los entomólogos de campo puedan registrar la abundancia de los mosquitos vectores y recoger datos sobre la resistencia a los insecticidas. La segunda es la implantación de ovitrampas autocidales para hembras grávidas (AGO, por su sigla en inglés), que son una manera alternativa de medir la abundancia de vectores. La tercera iniciativa es utilizar los datos recogidos por el sistema SIVIEN AEDES para elaborar modelos matemáticos que predigan la abundancia del A. aegypti hasta incluso en una cuadra de ciudad, de manera que las autoridades de salud pública puedan dirigir las intervenciones a vecindarios específicos dentro de las ciudades. Por último, Colombia está vigilando en quince ciudades prioritarias la resistencia a los insecticidas mediante ensayos biológicos y análisis moleculares, de esta forma se genera una base de datos exhaustiva sobre la que fundamentar las decisiones acerca del uso de insecticidas en las diferentes regiones. El paso siguiente será sincronizar los datos recopilados por el sistema SIVIEN AEDES con datos epidemiológicos y climáticos para poder entender mejor cómo se originan las variaciones locales en la dinámica de transmisión de los arbovirus. Al integrar estos datos de vigilancia, las autoridades sanitarias estarán mejor equipadas para encontrar soluciones oportunas y adecuadas para la situación específica, a fin de controlar y prevenir los brotes de arbovirus transmitidos por el Aedes.

Depois da epidemia de zika, intensificou-se o interesse na vigilância e controle dos vetores arbovirais Aedes aegypti e Aedes albopictus, mas muitos dos sistemas de vigilância existentes poderiam ser aprimorados. Muitos programas de controle de vetores são dirigidos pelos governos nacionais, mas implementados no âmbito local, o que leva à desconsideração de heterogeneidades espaciais em aspectos ecológicos e epidemiológicos. Além disso, é comum que dados entomológicos e epidemiológicos sejam coletados por agências governamentais separadas, o que pode desacelerar o controle de vetores em resposta aos surtos. A Colômbia adotou vários enfoques para abordar esses problemas. Primeiro, um sistema de vigilância de Aedes georreferenciado e baseado na Internet, chamado SIVIEN AEDES, foi desenvolvido para permitir aos entomólogos de campo registrar a abundância de vetores e a resistência aos inseticidas. Segundo, ovitrampas letais para fêmeas grávidas estão sendo mobilizadas como maneira alternativa de medir a abundância vetorial. Terceiro, os dados coletados pelo SIVIEN AEDES estão sendo utilizados para desenvolver modelos matemáticos para prever a abundância do Ae. aegypti até o nível de quadra/quarteirão, permitindo assim às autoridades de saúde pública direcionar intervenções para bairros específicos em cada município. Finalmente, a resistência aos inseticidas é monitorada através de ensaios biológicos e testes moleculares em 15 cidades de alta prioridade, o que proporciona uma base abrangente para subsidiar decisões sobre o uso de inseticida em diferentes regiões. O próximo passo será sincronizar os dados do SIVIEN AEDES com dados epidemiológicos e climáticos para melhorar a compreensão dos fatores que impulsionam variações locais na dinâmica da transmissão arboviral. Ao integrar esses dados de vigilância, as autoridades de saúde estarão mais bem equipadas para desenvolver soluções personalizadas e oportunas para controlar e prevenir os surtos de arbovírus transmitidos por mosquitos do gênero Aedes.

Enhanced vector surveillance to control arbovirus epidemics in Colombia

[ABSTRACT]. In the wake of the Zika epidemic, there has been intensified interest in the surveillance and control of the arbovirus vectors Aedes aegypti and Aedes albopictus, yet many existing surveillance systems could benefit from improvements. Vector control programs are often directed by national governments, but are carried out at the local level, resulting in the discounting of spatial heterogeneities in ecology and epidemiology. Furthermore, entomological and epidemiological data are often collected by separate governmental entities, which can slow vector control responses to outbreaks. Colombia has adopted several approaches to address these issues. First, a web-based, georeferenced Aedes surveillance system called SIVIEN AEDES was developed to allow field entomologists to record vector abundance and insecticide resistance data. Second, autocidal gravid oviposition (AGO) traps are deployed as an alternative way to measure vector abundance. Third, data collected by SIVIEN AEDES are used to develop mathematical models predicting Ae. aegypti abundance down to a city block, thus allowing public health authorities to target interventions to specific neighborhoods within cities. Finally, insecticide resistance is monitored through bioassays and molecular testing in 15 high-priority cities, providing a comprehensive basis to inform decisions about insecticide use in different regions. The next step will be to synchronize SIVIEN AEDES data together with epidemiological and climatic data to improve the understanding of the drivers of local variations in arbovirus transmission dynamics. By integrating these surveillance data, health authorities will be better equipped to develop tailored and timely solutions to control and prevent Aedes-borne arbovirus outbreaks.

[RESUMEN]. Tras la epidemia del Zika, se ha intensificado el interés en vigilar y controlar los vectores de arbovirus Aedes aegypti y Aedes albopictus. Aun así, muchos de los sistemas existentes de vigilancia necesitan mejorar. En general son los gobiernos nacionales los que dirigen los programas de control de vectores, aunque estos programas se llevan a cabo a nivel local, por lo que no se tiene en cuenta la heterogeneidad del lugar en cuanto a las características ecológicas y epidemiológicas. Además, normalmente los datos entomológicos y epidemiológicos son recopilados por entidades gubernamentales distintas, lo que puede ralentizar el control de vectores durante un brote. Colombia ha puesto en marcha varias iniciativas para abordar estas cuestiones. La primera es un sistema en línea de geolocación del mosquito Aedes, llamado SIVIEN AEDES, para que los entomólogos de campo puedan registrar la abundancia de los mosquitos vectores y recoger datos sobre la resistencia a los insecticidas. La segunda es la implantación de ovitrampas autocidales para hembras grávidas (AGO, por su sigla en inglés), que son una manera alternativa de medir la abundancia de vectores. La tercera iniciativa es utilizar los datos recogidos por el sistema SIVIEN AEDES para elaborar modelos matemáticos que predigan la abundancia del A. aegypti hasta incluso en una cuadra de ciudad, de manera que las autoridades de salud pública puedan dirigir las intervenciones a vecindarios específicos dentro de las ciudades. Por último, Colombia está vigilando en quince ciudades prioritarias la resistencia a los insecticidas mediante ensayos biológicos y análisis moleculares, de esta forma se genera una base de datos exhaustiva sobre la que fundamentar las decisiones acerca del uso de insecticidas en las diferentes regiones. El paso siguiente será sincronizar los datos recopilados por el sistema SIVIEN AEDES con datos epidemiológicos y climáticos para poder entender mejor cómo se originan las variaciones locales en la dinámica de transmisión de los arbovirus. Al integrar estos datos de vigilancia, las autoridades sanitarias estarán mejor equipadas para encontrar soluciones oportunas y adecuadas para la situación específica, a fin de controlar y prevenir los brotes de arbovirus transmitidos por el Aedes.

[RESUMO]. Depois da epidemia de zika, intensificou-se o interesse na vigilância e controle dos vetores arbovirais Aedes aegypti e Aedes albopictus, mas muitos dos sistemas de vigilância existentes poderiam ser aprimorados. Muitos programas de controle de vetores são dirigidos pelos governos nacionais, mas implementados no âmbito local, o que leva à desconsideração de heterogeneidades espaciais em aspectos ecológicos e epidemiológicos. Além disso, é comum que dados entomológicos e epidemiológicos sejam coletados por agências governamentais separadas, o que pode desacelerar o controle de vetores em resposta aos surtos. A Colômbia adotou vários enfoques para abordar esses problemas. Primeiro, um sistema de vigilância de Aedes georreferenciado e baseado na Internet, chamado SIVIEN AEDES, foi desenvolvido para permitir aos entomólogos de campo registrar a abundância de vetores e a resistência aos inseticidas. Segundo, ovitrampas letais para fêmeas grávidas estão sendo mobilizadas como maneira alternativa de medir a abundância vetorial. Terceiro, os dados coletados pelo SIVIEN AEDES estão sendo utilizados para desenvolver modelos matemáticos para prever a abundância do Ae. aegypti até o nível de quadra/quarteirão, permitindo assim às autoridades de saúde pública direcionar intervenções para bairros específicos em cada município. Finalmente, a resistência aos inseticidas é monitorada através de ensaios biológicos e testes moleculares em 15 cidades de alta prioridade, o que proporciona uma base abrangente para subsidiar decisões sobre o uso de inseticida em diferentes regiões. O próximo passo será sincronizar os dados do SIVIEN AEDES com dados epidemiológicos e climáticos para melhorar a compreensão dos fatores que impulsionam variações locais na dinâmica da transmissão arboviral. Ao integrar esses dados de vigilância, as autoridades de saúde estarão mais bem equipadas para desenvolver soluções personalizadas e oportunas para controlar e prevenir os surtos de arbovírus transmitidos por mosquitos do gênero Aedes.

Per- and polyfluoroalkyl substances in two different populations of northern cardinals.

The northern cardinal (Cardinalis cardinalis) is a good indicator species for environmental contaminants because it does not migrate and its range covers a diversity of habitats, including metropolitan Atlanta, GA and the geographically isolated Hawaiian Islands. In addition, the cardinal is often found near people's homes, making it likely to be exposed to the same outdoor elements, including soil, groundwater, and air, that surrounding humans experience. In this study, blood serum concentrations of 12 per- and polyfluoroalkyl substances (PFASs) were measured in 40 cardinals from Atlanta and 17 cardinals from the Big Island (Hawaii), HI. We observed significantly higher median concentrations of four PFASs and significantly higher detection frequencies of seven PFASs in the cardinals from Atlanta, relative to the PFAS median concentrations and detection frequencies observed in the cardinals from Hawaii (α = 0.05). Among the PFASs measured, perfluorooctane sulfonate (PFOS) was observed in the highest concentrations. A linear regression model controlling for sex, age, and airport distance did not explain PFOS variation within the Atlanta samples, but a similar model explained 90% of PFOS variation within the Hawaii samples. To our knowledge, these are the first measurements of PFASs in northern cardinals.

Avian species diversity and transmission of West Nile virus in Atlanta, Georgia.

BACKGROUND: The dilution effect is the reduction in vector-borne pathogen transmission associated with the presence of diverse potential host species, some of which are incompetent. It is popularized as the notion that increased biodiversity leads to decreased rates of disease. West Nile virus (WNV) is an endemic mosquito-borne virus in the United States that is maintained in a zoonotic cycle involving various avian host species. In Atlanta, Georgia, substantial WNV presence in the vector and host species has not translated into a high number of human cases. METHODS: To determine whether a dilution effect was contributing to this reduced transmission, we characterized the host species community composition and performed WNV surveillance of hosts and vectors in urban Atlanta between 2010 and 2011. We tested the relationship between host diversity and both host seroprevalence and vector infection rates using a negative binomial generalized linear mixed model. RESULTS: Regardless of how we measured host diversity or whether we considered host seroprevalence and vector infection rates as predictor variables or outcome variables, we did not detect a dilution effect. Rather, we detected an amplification effect, in which increased host diversity resulted in increased seroprevalence or infection rates; this is the first empirical evidence for this effect in a mosquito-borne system. CONCLUSIONS: We suggest that this effect may be driven by an over-abundance of moderately- to poorly-competent host species, such as northern cardinals and members of the Mimid family, which cause optimal hosts to become rarer and present primarily in species-rich areas. Our results support the notion that dilution or amplification effects depend more on the identities of the species comprising the host community than on the absolute diversity of hosts.

Supersuppression: Reservoir Competency and Timing of Mosquito Host Shifts Combine to Reduce Spillover of West Nile Virus.

In the eastern United States, human cases of West Nile virus (WNV) result from spillover from urban epizootic transmission between passerine birds and Culex mosquitoes. In Atlanta, GA, substantial WNV presence in hosts and vectors has not resulted in the human disease burden observed in cities with similar infection pressure. Our study goal was to investigate extrinsic ecological conditions that potentially contribute to these reduced transmission rates. We conducted WNV surveillance among hosts and vectors in urban Atlanta and recorded an overall avian seroprevalence of nearly 30%, which was significantly higher among northern cardinals, blue jays, and members of the mimid family, and notably low among American robins. Examination of temporal Culex feeding patterns showed a marked feeding shift from American robins in the early season to northern cardinals in the late season. We therefore rule out American robins as superspreaders in the Atlanta area and suggest instead that northern cardinals and mimids act as WNV "supersuppressor" species, which slow WNV transmission by drawing many infectious bites during the critical virus amplification period, yet failing to amplify transmission due to low host competencies. Of particular interest, urban forest patches provide spillover protection by increasing the WNV amplification fraction on supersuppressor species.

WEST NILE VIRUS ANTIBODY DECAY RATE IN FREE-RANGING BIRDS.

Antibody duration, following a humoral immune response to West Nile virus (WNV) infection, is poorly understood in free-ranging avian hosts. Quantifying antibody decay rate is important for interpreting serologic results and for understanding the potential for birds to serorevert and become susceptible again. We sampled free-ranging birds in Chicago, Illinois, US, from 2005 to 2011 and Atlanta, Georgia, US, from 2010 to 2012 to examine the dynamics of antibody decay following natural WNV infection. Using serial dilutions in a blocking enzyme-linked immunosorbent assay, we quantified WNV antibody titer in repeated blood samples from individual birds over time. We quantified a rate of antibody decay for 23 Northern Cardinals (Cardinalis cardinalis) of 0.198 natural log units per month and 24 individuals of other bird species of 0.178 natural log units per month. Our results suggest that juveniles had a higher rate of antibody decay than adults, which is consistent with nonlinear antibody decay at different times postexposure. Overall, most birds had undetectable titers 2 yr postexposure. Nonuniform WNV antibody decay rates in free-ranging birds underscore the need for cautious interpretation of avian serology results in the context of arbovirus surveillance and epidemiology.

Limited spillover to humans from West Nile Virus viremic birds in Atlanta, Georgia.

West Nile Virus (WNV) is a mosquito-borne pathogen that impacts the health of its passerine bird hosts as well as incidentally infected humans in the United States. Intensive enzootic activity among the hosts and vectors does not always lead to human outbreaks, as is the situation throughout much of the southeastern United States. In Georgia, substantial yearly evidence of WNV in the mosquito vectors and avian hosts since 2001 has only led to 324 human cases. Although virus has been consistently isolated from mosquitoes trapped in Atlanta, GA, little is known about viral activity among the passerine hosts. A possible reason for the suppression of WNV spillover to humans is that viremic birds are absent from high human-use areas of the city. To test this hypothesis, multiseason, multihabitat, longitudinal WNV surveillance for active WNV viremia was conducted within the avian host community of urban Atlanta by collection of blood samples from wild passerine birds in five urban microhabitats. WNV was isolated from the serum of six blood samples collected from 630 (0.95%) wild passerine birds in Atlanta during 2010-2012, a proportion similar to that found in the Chicago, IL, area in 2005, when over 200 human cases were reported. Most of the viremic birds were Northern Cardinals, suggesting they may be of particular importance to the WNV transmission cycle in Georgia. Results indicated active WNV transmission in all microhabitats of urban Atlanta, except in the old-growth forest patches. The number of viremic birds was highest in Zoo Atlanta, where 3.5% of samples were viremic. Although not significant, these observations may suggest a possible transmission reduction effect of urban old-growth forests and a potential role in WNV amplification for Zoo Atlanta. Overall, spillover to humans remains a rare occurrence in urban Atlanta settings despite active WNV transmission in the avian population.

Phylogenetic and ecologic perspectives of a monkeypox outbreak, southern Sudan, 2005.

Identification of human monkeypox cases during 2005 in southern Sudan (now South Sudan) raised several questions about the natural history of monkeypox virus (MPXV) in Africa. The outbreak area, characterized by seasonally dry riverine grasslands, is not identified as environmentally suitable for MPXV transmission. We examined possible origins of this outbreak by performing phylogenetic analysis of genome sequences of MPXV isolates from the outbreak in Sudan and from differing localities. We also compared the environmental suitability of study localities for monkeypox transmission. Phylogenetically, the viruses isolated from Sudan outbreak specimens belong to a clade identified in the Congo Basin. This finding, added to the political instability of the area during the time of the outbreak, supports the hypothesis of importation by infected animals or humans entering Sudan from the Congo Basin, and person-to-person transmission of virus, rather than transmission of indigenous virus from infected animals to humans.

Sealpox virus in marine mammal rehabilitation facilities, North America, 2007-2009.

Sealpox, a zoonotic disease affecting pinnipeds (seals and sea lions), can occur among captive and convalescing animals. We surveyed 1 worker each from 11 marine mammal centers and interviewed 31 other marine mammal workers to ascertain their knowledge of and experience with sealpox virus and to identify factors associated with sealpox virus outbreaks among pinnipeds in marine rehabilitation facilities. Demographic and health data were obtained for 1,423 pinnipeds at the 11 facilities. Among the 23 animals in which sealpox was clinically diagnosed, 4 arrived at the facility ill, 11 became ill <5 weeks after arrival, and 2 became ill ≥5 weeks after arrival; the timing of illness onset was unknown for 6 animals. Most infections occurred in pinnipeds <1 year of age. Nine affected animals were malnourished; 4 had additional illnesses. Sealpox had also occurred among workers at 2 facilities. Sealpox is a noteworthy zoonosis of rehabilitating convalescing pinnipeds; workplace education can help to minimize risks for human infection.

A method for statistically comparing spatial distribution maps.

BACKGROUND: Ecological niche modeling is a method for estimation of species distributions based on certain ecological parameters. Thus far, empirical determination of significant differences between independently generated distribution maps for a single species (maps which are created through equivalent processes, but with different ecological input parameters), has been challenging. RESULTS: We describe a method for comparing model outcomes, which allows a statistical evaluation of whether the strength of prediction and breadth of predicted areas is measurably different between projected distributions. To create ecological niche models for statistical comparison, we utilized GARP (Genetic Algorithm for Rule-Set Production) software to generate ecological niche models of human monkeypox in Africa. We created several models, keeping constant the case location input records for each model but varying the ecological input data. In order to assess the relative importance of each ecological parameter included in the development of the individual predicted distributions, we performed pixel-to-pixel comparisons between model outcomes and calculated the mean difference in pixel scores. We used a two sample Student's t-test, (assuming as null hypothesis that both maps were identical to each other regardless of which input parameters were used) to examine whether the mean difference in corresponding pixel scores from one map to another was greater than would be expected by chance alone. We also utilized weighted kappa statistics, frequency distributions, and percent difference to look at the disparities in pixel scores. Multiple independent statistical tests indicated precipitation as the single most important independent ecological parameter in the niche model for human monkeypox disease. CONCLUSION: In addition to improving our understanding of the natural factors influencing the distribution of human monkeypox disease, such pixel-to-pixel comparison tests afford users the ability to empirically distinguish the significance of each of the diverse environmental parameters included in the modeling process. This method will be particularly useful in situations where the outcomes (maps) appear similar upon visual inspection (as are generated with other modeling programs such as MAXENT), as it allows an investigator the capacity to explore subtle differences among ecological parameters and to demonstrate the individual importance of these factors within an overall model.

Spread of the tiger: global risk of invasion by the mosquito Aedes albopictus.

Aedes albopictus, commonly known as the Asian tiger mosquito, is currently the most invasive mosquito in the world. It is of medical importance due to its aggressive daytime human-biting behavior and ability to vector many viruses, including dengue, LaCrosse, and West Nile. Invasions into new areas of its potential range are often initiated through the transportation of eggs via the international trade in used tires. We use a genetic algorithm, Genetic Algorithm for Rule Set Production (GARP), to determine the ecological niche of Ae. albopictus and predict a global ecological risk map for the continued spread of the species. We combine this analysis with risk due to importation of tires from infested countries and their proximity to countries that have already been invaded to develop a list of countries most at risk for future introductions and establishments. Methods used here have potential for predicting risks of future invasions of vectors or pathogens.

Ecological niche and geographic distribution of human monkeypox in Africa.

Monkeypox virus, a zoonotic member of the genus Orthopoxviridae, can cause a severe, smallpox-like illness in humans. Monkeypox virus is thought to be endemic to forested areas of western and Central Africa. Considerably more is known about human monkeypox disease occurrence than about natural sylvatic cycles of this virus in non-human animal hosts. We use human monkeypox case data from Africa for 1970-2003 in an ecological niche modeling framework to construct predictive models of the ecological requirements and geographic distribution of monkeypox virus across West and Central Africa. Tests of internal predictive ability using different subsets of input data show the model to be highly robust and suggest that the distinct phylogenetic lineages of monkeypox in West Africa and Central Africa occupy similar ecological niches. High mean annual precipitation and low elevations were shown to be highly correlated with human monkeypox disease occurrence. The synthetic picture of the potential geographic distribution of human monkeypox in Africa resulting from this study should support ongoing epidemiologic and ecological studies, as well as help to guide public health intervention strategies to areas at highest risk for human monkeypox.

Distribution of members of Anopheles quadrimaculatus say s.l. (Diptera: Culicidae) and implications for their roles in malaria transmission in the United States.

The Anopheles quadrimaculatus s.l. (Say) complex consists of at least five species distinguished by distribution, genetic incompatibility, and allele frequencies. However, the distributions of the members have only been described by collection locations. Building on this information and environmental data, preliminary predictions of their distribution were produced using a genetic algorithm and point occurrence data. Based on resulting predicted border areas and undersampled regions, we obtained and analyzed additional geo-referenced specimens and compared their distribution with our preliminary predictions. We found good agreement between the preliminary predictions and the subsequent collections, regardless of the fact that additional specimens were deliberately sought from areas most likely to reveal inconsistencies. Final predicted distributions describe widespread distribution of A.quadrimaculatus throughout the eastern United States. A. maverlius and A. smaragdinus have similar predicted ranges limited to the southeastern United States. The predicted ranges of the sister taxa A. diluvialis and A. inundatus were similar to one another along the southeastern coast even though they seem to be allopatric. The historical role of A. quadrimaculatus s.l. in transmission of malaria was also examined. We conclude that A. quadrimaculatus s.s. was the only species of the complex capable of vectoring malaria in the United States throughout the area in which malaria occurred. However, any or all the members of the complex may have been regionally important, particularly in areas of most intense transmission.

Geographic and ecologic distributions of the Anopheles gambiae complex predicted using a genetic algorithm.

The distribution of the Anopheles gambiae complex of malaria vectors in Africa is uncertain due to under-sampling of vast regions. We use ecologic niche modeling to predict the potential distribution of three members of the complex (A. gambiae, A. arabiensis, and A. quadriannulatus) and demonstrate the statistical significance of the models. Predictions correspond well to previous estimates, but provide detail regarding spatial discontinuities in the distribution of A. gambiae s.s. that are consistent with population genetic studies. Our predictions also identify large areas of Africa where the presence of A. arabiensis is predicted, but few specimens have been obtained, suggesting under-sampling of the species. Finally, we project models developed from African distribution data for the late 1900s into the past and to South America to determine retrospectively whether the deadly 1929 introduction of A. gambiae sensu lato into Brazil was more likely that of A. gambiae sensu stricto or A. arabiensis.