Vector-borne disease surveillance and natural disasters

Spatial, Sociodemographic, and Weather Analysis of the Zika Virus Outbreak: U.S. Virgin Islands, January 2016-January 2018

Background: The first Zika virus outbreak in U.S. Virgin Islands identified 1031 confirmed noncongenital Zika disease (n = 967) and infection (n = 64) cases during January 2016-January 2018; most cases (89%) occurred during July-December 2016. Methods and Results: The epidemic followed a continued point-source outbreak pattern. Evaluation of sociodemographic risk factors revealed that estates with higher unemployment, more houses connected to the public water system, and more newly built houses were significantly less likely to have Zika virus disease and infection cases. Increased temperature was associated with higher case counts, which suggests a seasonal association of this outbreak. Conclusion: Vector surveillance and control measures are needed to prevent future outbreaks.

Operational Insights Into Mosquito Control Disaster Response in Coastal North Carolina: Experiences With the Federal Emergency Management Agency After Hurricane Florence

Preparation for post-hurricane mosquito control is essential for an effective emergency response to protect public health and promote recovery efforts. Effective pre-hurricane planning includes laying the groundwork for a successful reimbursement application to the Federal Emergency Management Agency. The critical and overlapping need to sustain funding for mosquito control programs is highlighted here in the context of both normal and emergency responses. Community support is an integral component of an effective integrated pest management program and is established over time with appropriate communication and engagement. Experienced mosquito control operators who are familiar with treatment areas are an essential component of successful operations. Here, practical advice is provided to plan, prepare, and implement a successful ground- and aerial-based mosquito control response.

Aging Hearts in a Hotter, More Turbulent World: The Impacts of Climate Change on the Cardiovascular Health of Older Adults

PURPOSE OF REVIEW

Climate change has manifested itself in multiple environmental hazards to human health. Older adults and those living with cardiovascular diseases are particularly susceptible to poor outcomes due to unique social, economic, and physiologic vulnerabilities. This review aims to summarize those vulnerabilities and the resultant impacts of climate-mediated disasters on the heart health of the aging population.

RECENT FINDINGS

Analyses incorporating a wide variety of environmental data sources have identified increases in cardiovascular risk factors, hospitalizations, and mortality from intensified air pollution, wildfires, heat waves, extreme weather events, rising sea levels, and pandemic disease. Older adults, especially those of low socioeconomic status or belonging to ethnic minority groups, bear a disproportionate health burden from these hazards. The worldwide trends responsible for global warming continue to worsen climate change-mediated natural disasters. As such, additional investigation will be necessary to develop personal and policy-level interventions to protect the cardiovascular wellbeing of our aging population.

The projected impacts of smart decline on urban runoff contamination levels

There has been mounting interest about how the repurposing of vacant land (VL) through green infrastructure (the most common smart decline strategy) can reduce stormwater runoff and improve runoff quality, especially in legacy cities characterized by excessive industrial land uses and VL amounts. This research examines the long-term impacts of smart decline on both stormwater amounts and pollutants loads through integrating land use prediction models with green infrastructure performance models. Using the City of St. Louis, Missouri, USA as the study area, we simulate 2025 land use change using the Conversion of Land Use and its Effects (CLUE-S) and Markov Chain urban land use prediction models and assess these change's probable impacts on urban contamination levels under different smart decline scenarios using the Long-Term Hydrologic Impact Assessment (L-THIA) performance model. The four different scenarios are: (1) a baseline scenario, (2) a 10% vacant land re-greening (VLRG) scenario, (3) a 20% VLRG scenario, and (4) a 30% VLRG scenario. The results of this study illustrate that smart decline VLRG strategies can have both direct and indirect impacts on urban stormwater runoff and their inherent contamination levels. Direct impacts on urban contamination include the reduction of stormwater runoff and non-point source (NPS) pollutants. In the 30% VLRG scenario, the annual runoff volume decreases by 11%, both physical, chemical, and bacterial pollutants are reduced by an average of 19%, compared to the baseline scenario. Indirect impacts include reduction of the possibility of illegal dumping on VL through mitigation and prevention of future vacancies.

The Complex Epidemiological Relationship between Flooding Events and Human Outbreaks of Mosquito-Borne Diseases: A Scoping Review

BACKGROUND

Climate change is expected to increase the frequency of flooding events. Although rainfall is highly correlated with mosquito-borne diseases (MBD) in humans, less research focuses on understanding the impact of flooding events on disease incidence. This lack of research presents a significant gap in climate change-driven disease forecasting.

OBJECTIVES

We conducted a scoping review to assess the strength of evidence regarding the potential relationship between flooding and MBD and to determine knowledge gaps.

METHODS

PubMed, Embase, and Web of Science were searched through 31 December 2020 and supplemented with review of citations in relevant publications. Studies on rainfall were included only if the operationalization allowed for distinction of unusually heavy rainfall events. Data were abstracted by disease (dengue, malaria, or other) and stratified by post-event timing of disease assessment. Studies that conducted statistical testing were summarized in detail.

RESULTS

From 3,008 initial results, we included 131 relevant studies (dengue n = 45 , malaria n = 61 , other MBD n = 49 ). Dengue studies indicated short-term (< 1  month ) decreases and subsequent (1-4 month) increases in incidence. Malaria studies indicated post-event incidence increases, but the results were mixed, and the temporal pattern was less clear. Statistical evidence was limited for other MBD, though findings suggest that human outbreaks of Murray Valley encephalitis, Ross River virus, Barmah Forest virus, Rift Valley fever, and Japanese encephalitis may follow flooding.

DISCUSSION

Flooding is generally associated with increased incidence of MBD, potentially following a brief decrease in incidence for some diseases. Methodological inconsistencies significantly limit direct comparison and generalizability of study results. Regions with established MBD and weather surveillance should be leveraged to conduct multisite research to a) standardize the quantification of relevant flooding, b) study nonlinear relationships between rainfall and disease, c) report outcomes at multiple lag periods, and d) investigate interacting factors that modify the likelihood and severity of outbreaks across different settings. https://doi.org/10.1289/EHP8887.

Harris County Public Health Mosquito and Vector Control Division Emergency Response to Hurricane Harvey: Vector-Borne Disease Surveillance and Control

Hurricane Harvey made a landfall on the Texas Gulf Coast on August 25, 2017, stalling over Harris County as a tropical storm for 4 days (August 26-29), dumping approximately 127 cm of rain. This tremendous amount of rainfall overwhelmed the county's natural and man-made drainage systems, resulting in unprecedented widespread flooding. Immediately following, Harris County Public Health Mosquito and Vector Control Division conducted a countywide emergency vector control response by integrating surveillance, control, and education strategies. This included landing rate counts, mosquito and avian surveillance, arbovirus testing, ground-based ultra-low volume (ULV) and aerial pesticide spraying, and community outreach. The immediate response lasted for 4 wk through September, resulting in 774 landing rates, 49,342 ha treated by ground-based ULV, 242,811 ha treated by aerial ULV, 83,241 mosquitoes collected, 1,807 mosquito pools tested, and 20 education/outreach sessions. Recovery activities of 3 additional education/outreach events continued through October while surveillance and control activities returned to routine status.

Disaster Vector Control in Mississippi After Hurricane Katrina: Lessons Learned

Hurricane Katrina devastated the Mississippi Gulf Coast on August 29, 2005, causing an ecological disaster. Mississippi State Department of Health (MSDH) entomologists established a vector control program in affected areas with the following objectives: 1) helping local vector control agencies reestablish services, 2) performing mosquito surveillance, and 3) establishing mosquito larviciding and adulticiding where necessary. The MSDH personnel also helped write Action Request Forms requesting assistance from the Federal Emergency Management Agency (FEMA) for increased ground spraying in the 6 lower counties. Mosquito surveillance was conducted daily for 2 wk after the storm, then weekly for another month. Sanitation lagged, with people using makeshift latrines or simply piles of rubbish for bathrooms. Filth flies contaminated food and food surfaces. Responders lived in tent cities, many allowing filth fly access. Approximately 2 wk after hurricane landfall, due to increasing mosquito numbers, MSDH entomologists requested FEMA for an aerial spraying of insecticide to reduce nuisance mosquito biting in the area. A private vendor made 1 application of naled (Dibrom®) insecticide in the 3 coastal counties, yielding over 90% control in entire counties in 1 night. No complaints or medical or environmental problems from the increased ground spraying and aerial spraying were reported. Overall, important lessons in disaster vector control were learned, including how to work effectively with Centers for Disease Control, FEMA, and the US Public Health Service personnel, how to manage the public relations/educational aspects, and how to avoid or mitigate political interference in the disaster response.

MOSQUITO CONTROL EMERGENCY PREPAREDNESS AND RESPONSE TO NATURAL DISASTERS

On February 9, 2019, the Bipartisan Budget Act of 2018 was signed into law and appropriated $200M in hurricane funding to the Centers for Disease Control and Prevention (CDC) for preparation, response, recovery, mitigation, and other expenses related to the consequences of Hurricanes Harvey, Irma, and Maria. The CDC then awarded, through CDC-RFA-TP18-1802 Cooperative Agreement for Emergency Response: Public Health Crisis Response notice of funding opportunity, $51,136,347 in extramural funding. Funding specific to vector-borne diseases, including intramural and extramural (partners and jurisdictions), was $37,628,235 to Florida, Georgia, Louisiana, Mississippi, Texas, Puerto Rico, and US Virgin Islands. State and territorial funding supported the implementation of conventional and novel mosquito control techniques, training for public health pest control applicators, replacement of mosquito surveillance and control supplies utilized in the aftermath of the 2017 hurricanes, insecticide resistance testing and training, and source reduction. Additionally, the CDC hurricane funding supported this special issue of the Journal of the American Mosquito Control Association (JAMCA) focused on mosquito control response in the wake of natural disasters. We invited hurricane relief funding grantees, mosquito control programs, academics, manufacturers, product distributors, and applicators to submit response plans or descriptive articles related to their experience with mosquito control after natural disasters. The objective of this special issue of JAMCA is to provide a comprehensive volume that includes resources to help guide mosquito control in areas affected by natural disasters. The shared experiences should serve to assist others involved in mosquito control in planning for and responding to natural disasters.

Meeting Increased Demand for Mosquito Adulticides Containing the Active Ingredient Naled Following Hurricanes and Tropical Storms

The occurrence of tropical storms and hurricanes is a certainty in the Atlantic Basin each year. Many of these never make landfall. Those that do can range in intensity from a weak tropical depression to a very destructive Category 5 hurricane. These storms often produce large amounts of rainfall and flooding, resulting in increases in the mosquito populations in the affected areas. In order to deal with this problem, aerial applications of insecticides over wide areas can provide relief to the impacted area, assisting in the recovery efforts. Meeting the demand for these sudden and large increases in the volume of the insecticide most commonly used in aerial applications requires great coordination, communication, and commitment. We describe the diverse entities involved in the manufacture, distribution, and use of the product and how this increase in need is recognized, managed, and satisfied in a compressed period of time.

Florida Keys Mosquito Control District Comprehensive Hurricane Plan

The hurricane plan developed by the Florida Keys Mosquito Control District and approved by vote of the Board of Commissioners is presented. The plan is intended to facilitate prompt resumption of services after a tropical cyclone (tropical storm or hurricane) and to give direction and instructions to District staff who evacuate before a storm makes landfall. Specific procedures are documented for before and after storms, including communication, preparation of buildings and vehicles, and evacuation. The need for food and water for staff immediately after a storm is specifically mentioned in the plan. The plan is composed of five main sections: general preparedness, Lower Keys procedures, Middle Keys procedures, Upper Keys procedures, and aerial operations procedures. Also included is a section covering satellite telephone operation and a list of telephone contacts for local government and law enforcement agencies. An addendum details the District's policy for compensation for public emergency response work so all employees are aware of how they will be paid during the storm recovery period.

Temporal and Spatial Impacts of Hurricane Damage on West Nile Virus Transmission and Human Risk

Hurricanes have profound impacts on zoonotic pathogen ecosystems that exhibit spatial and temporal waves in both distance from and time since the event. Wind, rain, and storm surge directly affect mosquito vectors and animal hosts of these pathogens. In this analysis, we apply a West Nile virus transmission model parameterized for the Northern coast of the Gulf of Mexico to explore the effect of event timing of hurricane landfall, time since the event, and damage extent on human West Nile virus neuro-invasive disease (WNV-NID) risk. Early-season hurricanes, which make landfall prior to the peak of baseline WNV transmission activity, increase the average total WNV-infectious mosquitoes for the year by 7.8% and human WNV-NID incidence by 94.3% across all areas with hurricane damage. The indirect effects on human exposure to mosquito bites in the immediate aftermath and long-term recovery from the event have strong impacts on the risk of infection. The resultant interactive direct and indirect storm effects on the pathogen system are spatially and temporally heterogenous among the generalized time and space categories modeled.

Past, Present, and Future Vulnerability to Dengue in Jamaica: A Spatial Analysis of Monthly Variations

Over the years, Jamaica has experienced sporadic cases of dengue fever. Even though the island is vulnerable to dengue, there is paucity in the spatio-temporal analysis of the disease using Geographic Information Systems (GIS) and remote sensing tools. Further, access to time series dengue data at the community level is a major challenge on the island. This study therefore applies the Water-Associated Disease Index (WADI) framework to analyze vulnerability to dengue in Jamaica based on past, current and future climate change conditions using three scenarios: (1) WorldClim rainfall and temperature dataset from 1970 to 2000; (2) Climate Hazard Group InfraRed Precipitation with Station data (CHIRPS) rainfall and land surface temperature (LST) as proxy for air temperature from the Moderate Resolution Imaging Spectroradiometer (MODIS) for the period 2002 to 2016, and (3) maximum temperature and rainfall under the Representative Concentration Pathway (RCP) 8.5 climate change scenario for 2030. downscaled at 25 km based on the Regional Climate Model, RegCM4.3.5. Although vulnerability to dengue varies spatially and temporally, a higher vulnerability was depicted in urban areas in comparison to rural areas. The results also demonstrate the possibility for expansion in the geographical range of dengue in higher altitudes under climate change conditions based on scenario 3. This study provides an insight into the use of data with different temporal and spatial resolution in the analysis of dengue vulnerability.

Impacts of Hurricanes Irma and Maria on Aedes aegypti Populations, Aquatic Habitats, and Mosquito Infections with Dengue, Chikungunya, and Zika Viruses in Puerto Rico

Puerto Rico was severely impacted by Hurricanes Irma and Maria in September 2017. The island has been endemic for dengue viruses (DENV) and recently suffered epidemics of chikungunya (CHIKV 2014) and Zika (ZIKV 2016) viruses. Although severe storms tend to increase the number of vector and nuisance mosquitoes, we do not know how they influence Aedes aegypti populations and arboviral transmission. We compared the abundance of female Ae. aegypti in autocidal gravid ovitraps (AGO traps), container habitats, and presence of RNA of DENV, CHIKV, and ZIKV in this vector before and after the hurricanes in Caguas city and in four communities in southern Puerto Rico. Two of these communities were under vector control using mass AGO trapping and the other two nearby communities were not. We also investigated mosquito species composition and relative abundance (females/trap) using Biogents traps (BG-2 traps) in 59 sites in metropolitan San Juan city after the hurricanes. Mosquitoes sharply increased 5 weeks after Hurricane Maria. Ensuing abundance of Ae. aegypti was higher in Caguas and in one of the southern communities without vector control. Aedes aegypti did not significantly change in the two areas with vector control. The most abundant mosquitoes among the 26 species identified in San Juan were Culex (Melanoconion) spp., Culex quinquefasciatus, Culex nigripalpus, and Ae. aegypti. No arboviruses were detected in Ae. aegypti following the hurricanes, in contrast with observations from the previous year, so that the potential for Aedes-borne arboviral outbreaks following the storms in 2017 was low.

Rift Valley fever in animals and humans: Current perspectives

Rift Valley fever (RVF) is an ecologically complex emerging arboviral disease that causes significant illness in both livestock and people. This review article is designed to assist the reader in understanding the varied aspects of RVF disease in animals and humans. The historical facets of RVF disease, including the evolution of human outbreaks, are presented and discussed. The different clinical presentations of human RVF disease and the underlying causes are then addressed. We explore the exposure and transmission potential of RVF in animals and people. In the concluding section, we discuss the historical role of RVF as a biological weapon. We conclude with an outline of the important unanswered questions for ongoing research into this important zoonotic disease.

The risk of Rift Valley fever virus introduction and establishment in the United States and European Union

Rift Valley fever virus (RVFV) is an arthropod-borne disease resulting in severe morbidity and mortality in both human and ruminant populations. First identified in Kenya in 1930, the geographical range of RVFV has been largely constrained to the African continent, yet has recently spread to new regions, and is identified as a priority disease with potential for geographic emergence. We present a systematic literature review assessing the potential for RVFV introduction and establishment in the United States (US) and European Union (EU). Viable pathways for the introduction of RVFV include: transport of virus-carrying vectors, importation of viremic hosts and intentional entry of RVFV as a biological weapon. It is generally assumed that the risk of RVFV introduction into the US or EU is low. We argue that the risk of sporadic introduction is likely high, though currently an insufficient proportion of such introductions coincide with optimal environmental conditions. Future global trends may increase the likelihood of risk factors for RVFV spread.

Prevalence of infectious diseases in cats and dogs rescued following Hurricane Katrina

OBJECTIVE

To determine the prevalence of infectious diseases of animal and zoonotic importance in cats and dogs rescued and transferred from the Gulf Coast region following Hurricane Katrina.

DESIGN

Cross-sectional study.

ANIMALS

414 dogs and 56 cats rescued and transferred from the Gulf Coast region within 4 months after the hurricane.

PROCEDURES

EDTA-anticoagulated blood and serum samples were tested via PCR and serologic assays for infectious diseases.

RESULTS

In dogs, prevalence was highest for anti-West Nile virus (WNV) antibodies (218/390 [55.9%]), Dirofilaria immitis antigen (195/400 [48.8%]), anti-Toxoplasma gondii antibodies (92/366 [25.1%]), and hemotropic mycoplasma DNA (40/345 [11.9%]). The DNA of Bartonella spp, Ehrlichia spp, or Babesia spp or anti-canine influenza virus antibodies were identified in < 2% of dogs. In cats, prevalence was highest for antibodies against Bartonella spp and DNA of Bartonella spp combined (49/55 [89.1 %]), anti-T gondii antibodies (13/55 [23.6%]), hemotropic mycoplasma DNA (5/47 [10.6%]), anti-WNV antibodies (5/48 [10.4%]), D immitis antigen (4/50 [8.0%]), and anti-FIV antibodies (4/56 [7.1%]). A total of 308 (74.4%) dogs and 52 (92.9%) cats had evidence of previous or current vector-borne infections.

CONCLUSIONS AND CLINICAL RELEVANCE

Cats and dogs rescued from the disaster region had evidence of multiple infectious diseases. The dispersal of potentially infectious animals to other regions of North America where some infections were not typically found could have contributed to new geographic ranges for these organisms or to underdiagnosis in affected animals because of a low index of suspicion in regions with low disease prevalence.

Rapid assessment of mosquitoes and arbovirus activity after floods in southeastern Kansas, 2007

A rapid assessment was conducted in July-August 2007 to determine the impact of heavy rains and early summer floods on the mosquitoes and arbovirus activity in 4 southeastern Kansas counties. During 10 days and nights of collections using different types and styles of mosquito traps, a total of 10,512 adult female mosquitoes representing 29 species were collected, including a new species record for Kansas (Psorophora mathesoni). High numbers of Aedes albopictus were collected. Over 4,000 specimens of 4 Culex species in 235 species-specific pools were tested for the presence of West Nile, St. Louis, and western equine encephalitis viruses. Thirty pools representing 3 Culex species were positive for West Nile virus (WNV). No other arboviruses were detected in the samples. Infection rates of WNV in Culex pipiens complex in 2 counties (10.7/1,000 to 22.6/1,000) and in Culex salinarius in 1 county (6.0/1,000) were sufficiently high to increase the risk of transmission to humans. The infection rate of WNV in Culex erraticus was 1.9/1,000 in one county. Two focal hot spots of intense WNV transmission were identified in Montgomery and Wilson counties, where infection rates in Cx. pipiens complex were 26/ 1,000 and 19.9/1,000, respectively. Despite confirmed evidence of WNV activity in the area, there was no increase in human cases of arboviral disease documented in the 4 counties for the remainder of 2007.

Climate and vectorborne diseases

Climate change could significantly affect vectorborne disease in humans. Temperature, precipitation, humidity, and other climatic factors are known to affect the reproduction, development, behavior, and population dynamics of the arthropod vectors of these diseases. Climate also can affect the development of pathogens in vectors, as well as the population dynamics and ranges of the nonhuman vertebrate reservoirs of many vectorborne diseases. Whether climate changes increase or decrease the incidence of vectorborne diseases in humans will depend not only on the actual climatic conditions but also on local nonclimatic epidemiologic and ecologic factors. Predicting the relative impact of sustained climate change on vectorborne diseases is difficult and will require long-term studies that look not only at the effects of climate change but also at the contributions of other agents of global change such as increased trade and travel, demographic shifts, civil unrest, changes in land use, water availability, and other issues. Adapting to the effects of climate change will require the development of adequate response plans, enhancement of surveillance systems, and development of effective and locally appropriate strategies to control and prevent vectorborne diseases.

Mosquito fauna and arbovirus surveillance in a coastal Mississippi community after Hurricane Katrina

Hurricane Katrina caused massive destruction and flooding along the Gulf Coast in August 2005. We collected mosquitoes and tested them for arboviral infection in a severely hurricane-damaged community to determine species composition and to assess the risk of a mosquito-borne epidemic disease in that community about 6 wk after the landfall of Hurricane Katrina. Light-trap collections yielded 8,215 mosquitoes representing 19 species, while limited gravid-trap collections were not productive. The most abundant mosquito species was Culex nigripalpus, which constituted 73.6% of all specimens. No arboviruses were detected in any of the mosquitoes collected in this survey, which did not support the assertion that human risk for arboviral infection was increased in the coastal community 6 wk after the hurricane.

Mosquitoborne infections after Hurricane Jeanne, Haiti, 2004

After Hurricane Jeanne in September 2004, surveillance for mosquitoborne diseases in Gonaïves, Haiti, identified 3 patients with malaria, 2 with acute dengue infections, and 2 with acute West Nile virus infections among 116 febrile patients. These are the first reported human West Nile virus infections on the island of Hispaniola.

Mosquitoborne infections after Hurricane Jeanne, Haiti, 2004

After Hurricane Jeanne in September 2004, surveillance for mosquitoborne diseases in Gonaïves, Haiti, identified 3 patients with malaria, 2 with acute dengue infections, and 2 with acute West Nile virus infections among 116 febrile patients. These are the first reported human West Nile virus infections on the island of Hispaniola.

Infectious diseases of severe weather-related and flood-related natural disasters

PURPOSE OF REVIEW

The present review will focus on some of the possible infectious disease consequences of disastrous natural phenomena and severe weather, with a particular emphasis on infections associated with floods and the destruction of infrastructure.

RECENT FINDINGS

The risk of infectious diseases after weather or flood-related natural disasters is often specific to the event itself and is dependent on a number of factors, including the endemicity of specific pathogens in the affected region before the disaster, the type of disaster itself, the impact of the disaster on water and sanitation systems, the availability of shelter, the congregating of displaced persons, the functionality of the surviving public health infrastructure, the availability of healthcare services, and the rapidity, extent, and sustainability of the response after the disaster. Weather events and floods may also impact disease vectors and animal hosts in a complex system.

SUMMARY

Weather or flood-related natural disasters may be associated with an increased risk of soft tissue, respiratory, diarrheal, and vector-borne infectious diseases among survivors and responders.

Public health issues in disasters

OBJECTIVE

This article outlines a number of important areas in which public health can contribute to making overall disaster management more effective. This article discusses health effects of some of the more important sudden impact natural disasters and potential future threats (e.g., intentional or deliberately released biologic agents) and outlines the requirements for effective emergency medical and public health response to these events.

CONCLUSION

All natural disasters are unique in that each affected region of the world has different social, economic, and health backgrounds. Some similarities exist, however, among the health effects of different natural disasters, which if recognized, can ensure that health and emergency medical relief and limited resources are well managed.

Pre-West Nile virus outbreak: perceptions and practices to prevent mosquito bites and viral encephalitis in the United States

Mosquitoes can transmit over 100 of the viruses that can cause encephalitis, meningitis, and hemorrhagic disease in humans (Chin 2000; Gubler 1996; Monath 1989). While much is known about the ecology, epidemiology, and clinical manifestations of the arboviral encephalitides (Campbell et al. 2002; Centers for Disease Control and Prevention 1997; Gubler 1998; Hayes 1989; Hubálek and Halouzka 1999), little empirical research exists regarding the U.S. population's knowledge of mosquitoes and arboviral encephalitis, particularly prior to the U.S. outbreak of West Nile virus (WNV) in 1999. A nationally representative 55-item survey instrument was successfully administered to 1,500 adults in the United States and an additional 250 adults in six states in the Northeast (Connecticut, Delaware, New Jersey, New York, Pennsylvania, and Rhode Island) regarding mosquitoes and mosquito-borne viral encephalitis. A summary outcome measure for mosquito bite prevention was created. Analyses revealed that the following were statistically significant predictors of behaviors taken to prevent mosquito bites: being concerned about being bitten by mosquitoes, perceived effectiveness of staying indoors in late afternoon and early evening was protective, perceived effectiveness that mosquito repellent is not harmful to health, owning dogs and/or cats as pets, being married, and being > or = 18-44 years old. Being concerned about being bitten by mosquitoes was the most robust predictor of behavioral action to prevent mosquito bites (OR = 7.3; 95% CI = 4.3, 12.2). Observed misperceptions and inadequate knowledge regarding insect repellents suggest increased promotion of the safety and efficacy of DEET-containing insect repellents is warranted.

The potential impacts of climate variability and change on health impacts of extreme weather events in the United States

Extreme weather events such as precipitation extremes and severe storms cause hundreds of deaths and injuries annually in the United States. Climate change may alter the frequency, timing, intensity, and duration of these events. Increases in heavy precipitation have occurred over the past century. Future climate scenarios show likely increases in the frequency of extreme precipitation events, including precipitation during hurricanes, raising the risk of floods. Frequencies of tornadoes and hurricanes cannot reliably be projected. Injury and death are the direct health impacts most often associated with natural disasters. Secondary effects, mediated by changes in ecologic systems and public health infrastructure, also occur. The health impacts of extreme weather events hinge on the vulnerabilities and recovery capacities of the natural environment and the local population. Relevant variables include building codes, warning systems, disaster policies, evacuation plans, and relief efforts. There are many federal, state, and local government agencies and nongovernmental organizations involved in planning for and responding to natural disasters in the United States. Future research on health impacts of extreme weather events should focus on improving climate models to project any trends in regional extreme events and as a result improve public health preparedness and mitigation. Epidemiologic studies of health effects beyond the direct impacts of disaster will provide a more accurate measure of the full health impacts and will assist in planning and resource allocation.

Climate variability and change in the United States: potential impacts on vector- and rodent-borne diseases

Diseases such as plague, typhus, malaria, yellow fever, and dengue fever, transmitted between humans by blood-feeding arthropods, were once common in the United States. Many of these diseases are no longer present, mainly because of changes in land use, agricultural methods, residential patterns, human behavior, and vector control. However, diseases that may be transmitted to humans from wild birds or mammals (zoonoses) continue to circulate in nature in many parts of the country. Most vector-borne diseases exhibit a distinct seasonal pattern, which clearly suggests that they are weather sensitive. Rainfall, temperature, and other weather variables affect in many ways both the vectors and the pathogens they transmit. For example, high temperatures can increase or reduce survival rate, depending on the vector, its behavior, ecology, and many other factors. Thus, the probability of transmission may or may not be increased by higher temperatures. The tremendous growth in international travel increases the risk of importation of vector-borne diseases, some of which can be transmitted locally under suitable circumstances at the right time of the year. But demographic and sociologic factors also play a critical role in determining disease incidence, and it is unlikely that these diseases will cause major epidemics in the United States if the public health infrastructure is maintained and improved.

Climate variability and change in the United States: potential impacts on vector- and rodent-borne diseases

Diseases such as plague, typhus, malaria, yellow fever, and dengue fever, transmitted between humans by blood-feeding arthropods, were once common in the United States. Many of these diseases are no longer present, mainly because of changes in land use, agricultural methods, residential patterns, human behavior, and vector control. However, diseases that may be transmitted to humans from wild birds or mammals (zoonoses) continue to circulate in nature in many parts of the country. Most vector-borne diseases exhibit a distinct seasonal pattern, which clearly suggests that they are weather sensitive. Rainfall, temperature, and other weather variables affect in many ways both the vectors and the pathogens they transmit. For example, high temperatures can increase or reduce survival rate, depending on the vector, its behavior, ecology, and many other factors. Thus, the probability of transmission may or may not be increased by higher temperatures. The tremendous growth in international travel increases the risk of importation of vector-borne diseases, some of which can be transmitted locally under suitable circumstances at the right time of the year. But demographic and sociologic factors also play a critical role in determining disease incidence, and it is unlikely that these diseases will cause major epidemics in the United States if the public health infrastructure is maintained and improved.

The potential impacts of climate variability and change on health impacts of extreme weather events in the United States

Extreme weather events such as precipitation extremes and severe storms cause hundreds of deaths and injuries annually in the United States. Climate change may alter the frequency, timing, intensity, and duration of these events. Increases in heavy precipitation have occurred over the past century. Future climate scenarios show likely increases in the frequency of extreme precipitation events, including precipitation during hurricanes, raising the risk of floods. Frequencies of tornadoes and hurricanes cannot reliably be projected. Injury and death are the direct health impacts most often associated with natural disasters. Secondary effects, mediated by changes in ecologic systems and public health infrastructure, also occur. The health impacts of extreme weather events hinge on the vulnerabilities and recovery capacities of the natural environment and the local population. Relevant variables include building codes, warning systems, disaster policies, evacuation plans, and relief efforts. There are many federal, state, and local government agencies and nongovernmental organizations involved in planning for and responding to natural disasters in the United States. Future research on health impacts of extreme weather events should focus on improving climate models to project any trends in regional extreme events and as a result improve public health preparedness and mitigation. Epidemiologic studies of health effects beyond the direct impacts of disaster will provide a more accurate measure of the full health impacts and will assist in planning and resource allocation.