Vector-borne diseases are transmitted from one animal to another by vectors, including insects, such as mosquitoes or fleas, and arachnids, such as ticks. The USGS National Wildlife Health Center investigates wildlife diseases, including vector-borne diseases, such as West Nile virus and sylvatic plague.
The following are vector-borne diseases currently being studied by the USGS National Wildlife Health Center (NWHC).
West Nile Virus
West Nile virus, a mosquito-transmitted virus, was introduced into the New York City area of North America in 1999. Since then the virus has been transmitted throughout the continental U.S., southern Canadian Provinces, Mexico. The virus has also been transmitted on the Caribbean islands, Central and South America. West Nile virus causes disease symptoms, including encephalitis, in humans and horses, but has been devastating to North American wild bird populations, particularly the corvids, raptors, and songbirds. Population declines in members of these bird groups have been documented and linked to the year West Nile virus emerged in states or geographic areas of the U.S.
The NWHC has been involved with West Nile virus surveillance in wild birds and research since the entry of the virus into the U.S. In recent years we have assisted states and Tribes in monitoring for virus transmission in ruffed grouse (Bonasa umbellus), snow shoe hares (Lepus americanus), and wild wolves (Canus lupus). Experimentally, the NWHC has been working to develop models of West Nile virus susceptibility in passerine, or song birds, using domesticated zebra finches (Taeniopygia guttata) and canaries (Serinus canaria), which show lower and higher susceptibility to the virus, respectively. Since the genome of these domesticated birds has been published studies on molecular basis of disease susceptibility are possible.
West Nile virus continues to circulate every summer in the U.S. An uptick in human, domestic animal, and avian cases, might be related to weather, with hot and dry conditions being permissive, and also cycles of immunity in birds, the primary host for the virus.
To see disease reports of West Nile virus, search WHISPers (Wildlife Health Information Sharing Partnership event reporting system.
To check out historic fact sheets on West Nile virus, see – NWHC Fact Sheets.
Sylvatic Plague
Sylvatic plague, caused by Yersinia pestis, is a bacterial disease transmitted by fleas that afflicts many mammalian species, including humans. For many species of wildlife, plague mortality is a serious conservation issue. Current efforts to halt the spread of plague in prairie dog colonies typically rely on dusting individual prairie dog burrows with pesticides to kill plague-infected fleas. Although flea-control insecticides, such as deltamethrin, are useful in stopping plague outbreaks in these prairie dog colonies, dusting of burrows is labor intensive and time consuming and may affect other insects and arthropods.
Scientists at the USGS National Wildlife Health Center (NWHC), in collaboration with colleagues at the University of Wisconsin (UW), have developed a sylvatic plague vaccine that shows great promise in protecting prairie dogs against plague. Controlling plague is a vital concern for ongoing management and conservation efforts for prairie dogs.
To learn more about sylvatic plague and read related publications, see – Sylvatic Plague and Vaccines.
Below are other science projects related to vector-borne diseases.
Vaccines
Sylvatic Plague
Below are publications related to vector-borne diseases.
Effect of climate change on disease spread in wildlife
West Nile virus infection in American singer canaries: An experimental model in a highly susceptible avian species
Factors influencing uptake of sylvatic plague vaccine baits by prairie dogs
Stress hormones predict a host superspreader phenotype in the West Nile virus system
An examination of the effect of aerosolized permanone insecticide on zebra finch susceptibility to West Nile virus
Serosurvey for West Nile virus antibodies in Steller's Jays (Cyanocitta stelleri) captured in coastal California
Transcriptional response to West Nile virus infection in the zebra finch (Taeniopygia guttata)
Potential for water borne and invertebrate transmission of West Nile virus in the Great Salt Lake, Utah
Susceptibility and antibody response of the laboratory model zebra finch (Taeniopygia guttata) to West Nile Virus
Survey for West Nile virus antibodies in wild ducks, 2004-06, USA
Susceptibility and antibody response of Vesper Sparrows (Pooecetes gramineus) to West Nile virus: A potential amplification host in sagebrush-grassland habitat
Surveillance potential of non-native Hawaiian birds for detection of West Nile Virus
Below are news stories associated with this project.
Below are FAQs associated related to vector-borne diseases.
Are birds the only species that is susceptible to West Nile Virus infection?
West Nile Virus (WNV) has been detected in at least 48 species of mosquitoes, over 320 species of birds, at least 2 species of reptiles, and more than 25 mammalian species, including horses and humans. Birds are the natural host and reservoir of WNV. Although other animals are susceptible to WNV infection, only birds develop a high enough virus load to transmit the infection to an uninfected...
Can hunters get West Nile Virus from eating infected game birds?
Some game birds have tested positive for West Nile Virus (WNV). However, there is no evidence of human infection by consumption of properly cooked infected game. Hunters are likely at higher risk of infection by mosquito exposure, particularly in wetland environments. Protective measures should be taken to prevent mosquito exposure while hunting. There are extremely rare cases of laboratory...
Can my dog or cat get West Nile Virus by eating an infected animal?
Experimentally, it was found that this might be possible. However, there has been no evidence to indicate that West Nile Virus can be naturally transmitted to cats or dogs that carry or consume infected animals. Dogs and cats can be infected with West Nile Virus through the bite of a mosquito, so minimizing their exposure to mosquitoes is recommended.
How do I handle a sick or dead animal that might have West Nile Virus?
Under normal conditions, humans are unlikely to be infected with West Nile Virus by handling a sick or dead animal. However, there are a number of other infections that could potentially result from handling an animal. To protect yourself from exposure to any illness, you should wear gloves or put a plastic bag over your hand before touching the animal and you should wash your hands with soap and...
How do I know if an animal is infected with West Nile Virus?
Signs of infection in wildlife, like in humans, can range from no symptoms to severe symptoms of neurologic illness. Commonly reported signs in animals include weakness, stumbling, trembling, head tremors, inability to fly/walk, and a lack of awareness that allows them to be easily approached and handled. These symptoms, however, can also have other causes. The only way to positively confirm West...
Is there a West Nile Virus vaccine available for birds?
At this time, there is not a West Nile Virus vaccine approved for use in birds. The Centers for Disease Control and Prevention, in collaboration with several organizations and laboratories, is developing and testing vaccines for use in birds. Many zoos and wildlife centers have been using the Fort Dodge horse vaccine (West Nile-Innovator®) in birds. The vaccine has not been tested for use in birds...
What is the threat from West Nile Virus (WNV) to endangered and threatened bird species?
This is an issue of great concern, as these populations are already struggling to survive in the current environment. If some of these species are more vulnerable to fatal WNV infection, WNV may ultimately lead to their extinction or significantly set back the progress of the recovery programs.
Where in the United States has West Nile Virus been detected in wildlife?
West Nile Virus has been detected in all conterminous states of the U.S., the District of Columbia, and Puerto Rico. Alaska, Hawaii, and Guam have no reported cases of West Nile virus in humans or animals. Distribution maps are available from the Centers for Disease Control. Learn more: Vector-Borne Diseases
- Overview
Vector-borne diseases are transmitted from one animal to another by vectors, including insects, such as mosquitoes or fleas, and arachnids, such as ticks. The USGS National Wildlife Health Center investigates wildlife diseases, including vector-borne diseases, such as West Nile virus and sylvatic plague.
The following are vector-borne diseases currently being studied by the USGS National Wildlife Health Center (NWHC).
West Nile Virus
West Nile virus, a mosquito-transmitted virus, was introduced into the New York City area of North America in 1999. Since then the virus has been transmitted throughout the continental U.S., southern Canadian Provinces, Mexico. The virus has also been transmitted on the Caribbean islands, Central and South America. West Nile virus causes disease symptoms, including encephalitis, in humans and horses, but has been devastating to North American wild bird populations, particularly the corvids, raptors, and songbirds. Population declines in members of these bird groups have been documented and linked to the year West Nile virus emerged in states or geographic areas of the U.S.
Mosquito, species not verified(Public domain.) The NWHC has been involved with West Nile virus surveillance in wild birds and research since the entry of the virus into the U.S. In recent years we have assisted states and Tribes in monitoring for virus transmission in ruffed grouse (Bonasa umbellus), snow shoe hares (Lepus americanus), and wild wolves (Canus lupus). Experimentally, the NWHC has been working to develop models of West Nile virus susceptibility in passerine, or song birds, using domesticated zebra finches (Taeniopygia guttata) and canaries (Serinus canaria), which show lower and higher susceptibility to the virus, respectively. Since the genome of these domesticated birds has been published studies on molecular basis of disease susceptibility are possible.
West Nile virus continues to circulate every summer in the U.S. An uptick in human, domestic animal, and avian cases, might be related to weather, with hot and dry conditions being permissive, and also cycles of immunity in birds, the primary host for the virus.
To see disease reports of West Nile virus, search WHISPers (Wildlife Health Information Sharing Partnership event reporting system.
To check out historic fact sheets on West Nile virus, see – NWHC Fact Sheets.
Sylvatic Plague
Sylvatic plague, caused by Yersinia pestis, is a bacterial disease transmitted by fleas that afflicts many mammalian species, including humans. For many species of wildlife, plague mortality is a serious conservation issue. Current efforts to halt the spread of plague in prairie dog colonies typically rely on dusting individual prairie dog burrows with pesticides to kill plague-infected fleas. Although flea-control insecticides, such as deltamethrin, are useful in stopping plague outbreaks in these prairie dog colonies, dusting of burrows is labor intensive and time consuming and may affect other insects and arthropods.
National Park Service veterinarian Kevin Castle checks an anaesthetized prairie dog for fleas in Wind Cave National Park. Over 30 organizations and agencies are testing a USGS-developed oral vaccine to prevent the spread of plague in prairie dogs. If successful, the sylvatic plague vaccine could help protect endangered black-footed ferrets in the western U.S. because the ferrets rely on prairie dogs for food. Castle tags each trapped prairie dog and takes hair, whisker, and blood samples before scientists release the animals back into the wild.(Credit: Marisa Lubeck, U.S. Geological Survey. Public domain.) Scientists at the USGS National Wildlife Health Center (NWHC), in collaboration with colleagues at the University of Wisconsin (UW), have developed a sylvatic plague vaccine that shows great promise in protecting prairie dogs against plague. Controlling plague is a vital concern for ongoing management and conservation efforts for prairie dogs.
To learn more about sylvatic plague and read related publications, see – Sylvatic Plague and Vaccines.
- Science
Below are other science projects related to vector-borne diseases.
Vaccines
The USGS National Wildlife Health Center (NWHC) works on developing various disease management tools, including the development of vaccines. Our current work focuses on vaccines for sylvatic plague, white-nose syndrome, and rabies as disease control strategies.Sylvatic Plague
Sylvatic plague, caused by Yersinia pestis, is a bacterial disease transmitted by fleas that afflicts many mammalian species, including humans. - Publications
Below are publications related to vector-borne diseases.
Filter Total Items: 40Effect of climate change on disease spread in wildlife
A growing body of evidence indicates that climate change alone, or acting synergistically with current anthropogenic threats, is affecting the health of wild populations of aquatic and terrestrial wildlife. Measurable by-products of climate change include elevated atmospheric concentrations of greenhouse gases, higher average global temperatures; variations in global precipitation patterns, risingAuthorsErik K. Hofmeister, Caroline R. Van HemertWest Nile virus infection in American singer canaries: An experimental model in a highly susceptible avian species
This study investigated the susceptibility of American singer canaries (Serinus canaria) to West Nile virus (WNV) infection. Adult canaries were inoculated with 105, 102, and 101plaque forming units (PFU) of WNV. All birds became infected and mortality occurred by 5 days postinoculation. The load of viral RNA as determined by RT-qPCR was dose dependent, and was higher at all doses than the level oAuthorsErik K. Hofmeister, Melissa Lund, Valerie I. Shearn-BochslerFactors influencing uptake of sylvatic plague vaccine baits by prairie dogs
Sylvatic plague vaccine (SPV) is a virally vectored bait-delivered vaccine expressing Yersinia pestis antigens that can protect prairie dogs (Cynomys spp.) from plague and has potential utility as a management tool. In a large-scale 3-year field trial, SPV-laden baits containing the biomarker rhodamine B (used to determine bait consumption) were distributed annually at a rate of approximately 100–AuthorsRachel C. Abbott, Robin E. Russell, Katherine Richgels, Daniel W. Tripp, Marc R. Matchett, Dean E. Biggins, Tonie E. RockeStress hormones predict a host superspreader phenotype in the West Nile virus system
Glucocorticoid stress hormones, such as corticosterone (CORT), have profound effects on the behaviour and physiology of organisms, and thus have the potential to alter host competence and the contributions of individuals to population- and community-level pathogen dynamics. For example, CORT could alter the rate of contacts among hosts, pathogens and vectors through its widespread effects on hostAuthorsStephanie Gervasi, Sarah Burgan, Erik K. Hofmeister, Thomas R. Unnasch, Lynn B. MartinAn examination of the effect of aerosolized permanone insecticide on zebra finch susceptibility to West Nile virus
West Nile virus is primarily maintained cryptically primarily in avian (Passerine) populations where it is transmitted by Culex spp. mosquitoes. Mosquito control measures currently include physical activities to reduce mosquito breeding sites, the application of mosquito larvicides, or aerosolized insecticides to kill adults (adulticides) when arboviral diseases such as West Nile virus (WNV) or ZiAuthorsMark D. Jankowski, E. Moore Murray, Erik K. HofmeisterSerosurvey for West Nile virus antibodies in Steller's Jays (Cyanocitta stelleri) captured in coastal California
West Nile virus (WNV) was first detected in New York in 1999 and, during its expansion across the continental US, southern Canada, and Mexico, members of the Corvidae (ravens, crows, magpies, and jays) were frequently infected and highly susceptible to the virus. As part of a behavioral study of Steller's Jays (Cyanocitta stelleri) conducted from 2011–2014 in the coastal California counties of SanAuthorsElena West, Erik K. Hofmeister, M. Zach PeeryTranscriptional response to West Nile virus infection in the zebra finch (Taeniopygia guttata)
West Nile virus (WNV) is a widespread arbovirus that imposes a significant cost to both human and wildlife health. WNV exists in a bird-mosquito transmission cycle in which passerine birds act as the primary reservoir host. As a public health concern, the mammalian immune response to WNV has been studied in detail. Little, however, is known about the avian immune response to WNV. Avian taxa show vAuthorsDaniel J. Newhouse, Erik K. Hofmeister, Christopher N. BalakrishnanPotential for water borne and invertebrate transmission of West Nile virus in the Great Salt Lake, Utah
In November and December of 2013, a large mortality event involving 15,000 - 20,000 eared grebes (Podiceps nigricollis) occurred at the Great Salt Lake (GSL), UT. The onset of the outbreak in grebes was followed by a mortality event in > 86 bald eagles (Haliaeetus leucocephalus). During the die-off, West Nile virus (WNV) was detected by RT-PCR or viral culture in carcasses of grebes and eagles subAuthorsMelissa Lund, Valerie I. Shearn-Bochsler, Robert J. Dusek, Jan Shivers, Erik K. HofmeisterSusceptibility and antibody response of the laboratory model zebra finch (Taeniopygia guttata) to West Nile Virus
Since the introduction of West Nile virus (WNV) into North America in 1999 a number of passerine bird species have been found to play a role in the amplification of the virus. Arbovirus surveillance, observational studies and experimental studies have implicated passerine birds (songbirds, e.g., crows, American robins, house sparrows, and house finches) as significant reservoirs of WNV in North AmAuthorsErik K. Hofmeister, Melissa Lund, Valerie I. Shearn-Bochsler, Christopher N. BalakrishnanSurvey for West Nile virus antibodies in wild ducks, 2004-06, USA
Detection of West Nile virus (WNV) in ducks has been reported in North America in isolated cases of mortality in wild waterbirds and following outbreaks in farmed ducks. Although the virus has been noted as an apparent incidental finding in several species of ducks, little is known about the prevalence of exposure or the outcome of infection with WNV in wild ducks in North America. From 2004–06, wAuthorsErik K. Hofmeister, Mark D. Jankowski, Diana R. Goldberg, J. Christian FransonSusceptibility and antibody response of Vesper Sparrows (Pooecetes gramineus) to West Nile virus: A potential amplification host in sagebrush-grassland habitat
West Nile virus (WNV) spread to the US western plains states in 2003, when a significant mortality event attributed to WNV occurred in Greater Sage-grouse ( Centrocercus urophasianus ). The role of avian species inhabiting sagebrush in the amplification of WNV in arid and semiarid regions of the North America is unknown. We conducted an experimental WNV challenge study in Vesper Sparrows ( PooecetAuthorsErik K. Hofmeister, Robert J. Dusek, Carol Fassbinder-Orth, Benjamin Owen, J. Christian FransonSurveillance potential of non-native Hawaiian birds for detection of West Nile Virus
West Nile virus (WNV) was first detected in North America in 1999. Alaska and Hawaii (HI) remain the only U.S. states in which transmission of WNV has not been detected. Dead bird surveillance has played an important role in the detection of the virus geographically, as well as temporally. In North America, corvids have played a major role in WNV surveillance; however, the only corvid in HI is theAuthorsErik K. Hofmeister, Robert J. Dusek, Christopher J. Brand - News
Below are news stories associated with this project.
- FAQ
Below are FAQs associated related to vector-borne diseases.
Are birds the only species that is susceptible to West Nile Virus infection?
West Nile Virus (WNV) has been detected in at least 48 species of mosquitoes, over 320 species of birds, at least 2 species of reptiles, and more than 25 mammalian species, including horses and humans. Birds are the natural host and reservoir of WNV. Although other animals are susceptible to WNV infection, only birds develop a high enough virus load to transmit the infection to an uninfected...
Can hunters get West Nile Virus from eating infected game birds?
Some game birds have tested positive for West Nile Virus (WNV). However, there is no evidence of human infection by consumption of properly cooked infected game. Hunters are likely at higher risk of infection by mosquito exposure, particularly in wetland environments. Protective measures should be taken to prevent mosquito exposure while hunting. There are extremely rare cases of laboratory...
Can my dog or cat get West Nile Virus by eating an infected animal?
Experimentally, it was found that this might be possible. However, there has been no evidence to indicate that West Nile Virus can be naturally transmitted to cats or dogs that carry or consume infected animals. Dogs and cats can be infected with West Nile Virus through the bite of a mosquito, so minimizing their exposure to mosquitoes is recommended.
How do I handle a sick or dead animal that might have West Nile Virus?
Under normal conditions, humans are unlikely to be infected with West Nile Virus by handling a sick or dead animal. However, there are a number of other infections that could potentially result from handling an animal. To protect yourself from exposure to any illness, you should wear gloves or put a plastic bag over your hand before touching the animal and you should wash your hands with soap and...
How do I know if an animal is infected with West Nile Virus?
Signs of infection in wildlife, like in humans, can range from no symptoms to severe symptoms of neurologic illness. Commonly reported signs in animals include weakness, stumbling, trembling, head tremors, inability to fly/walk, and a lack of awareness that allows them to be easily approached and handled. These symptoms, however, can also have other causes. The only way to positively confirm West...
Is there a West Nile Virus vaccine available for birds?
At this time, there is not a West Nile Virus vaccine approved for use in birds. The Centers for Disease Control and Prevention, in collaboration with several organizations and laboratories, is developing and testing vaccines for use in birds. Many zoos and wildlife centers have been using the Fort Dodge horse vaccine (West Nile-Innovator®) in birds. The vaccine has not been tested for use in birds...
What is the threat from West Nile Virus (WNV) to endangered and threatened bird species?
This is an issue of great concern, as these populations are already struggling to survive in the current environment. If some of these species are more vulnerable to fatal WNV infection, WNV may ultimately lead to their extinction or significantly set back the progress of the recovery programs.
Where in the United States has West Nile Virus been detected in wildlife?
West Nile Virus has been detected in all conterminous states of the U.S., the District of Columbia, and Puerto Rico. Alaska, Hawaii, and Guam have no reported cases of West Nile virus in humans or animals. Distribution maps are available from the Centers for Disease Control. Learn more: Vector-Borne Diseases