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Richard J Douglass - One of the best experts on this subject based on the ideXlab platform.
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Population Density and Seasonality Effects on Sin Nombre Virus Transmission in North American Deermice (Peromyscus maniculatus) in Outdoor Enclosures
2016Co-Authors: Karoun H Bagamian, Lance A Waller, Amy J Kuenzi, Richard J Douglass, Arlene Alvarado, Brian R Amman, James N MillsAbstract:Surveys of wildlife host-pathogen systems often document clear seasonal variation in transmission; conclusions concerning the relationship between host population density and transmission vary. In the field, effects of seasonality and population density on natural disease cycles are challenging to measure independently, but laboratory experiments may poorly reflect what happens in nature. Outdoor manipulative experiments are an alternative that controls for some variables in a relatively natural environment. Using outdoor enclosures, we tested effects of North American deermouse (Peromyscus maniculatus) population density and season on transmission dynamics of Sin Nombre hantavirus. In early summer, mid-summer, late summer, and fall 2007–2008, predetermined numbers of infected and uninfected adult wild deermice were released into enclosures and trapped weekly or bi-weekly. We documented 18 transmission events and observed significant seasonal effects on transmission, wounding frequency, and host breeding condition. Apparent differences in transmission incidence or wounding frequency between high- and low-density treatments were not statistically significant. However, high host density was associated with a lower proportion of males with scrotal testes. Seasonality may have a stronger influence on disease transmission dynamics than host population density, and density effects cannot be considered independent o
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population density and seasonality effects on sin nombre virus transmission in north american deermice Peromyscus maniculatus in outdoor enclosures
PLOS ONE, 2012Co-Authors: Karoun H Bagamian, Lance A Waller, Amy J Kuenzi, Richard J Douglass, James N Mills, Arlene Alvarado, Brian R AmmanAbstract:Surveys of wildlife host-pathogen systems often document clear seasonal variation in transmission; conclusions concerning the relationship between host population density and transmission vary. In the field, effects of seasonality and population density on natural disease cycles are challenging to measure independently, but laboratory experiments may poorly reflect what happens in nature. Outdoor manipulative experiments are an alternative that controls for some variables in a relatively natural environment. Using outdoor enclosures, we tested effects of North American deermouse (Peromyscus maniculatus) population density and season on transmission dynamics of Sin Nombre hantavirus. In early summer, mid-summer, late summer, and fall 2007–2008, predetermined numbers of infected and uninfected adult wild deermice were released into enclosures and trapped weekly or bi-weekly. We documented 18 transmission events and observed significant seasonal effects on transmission, wounding frequency, and host breeding condition. Apparent differences in transmission incidence or wounding frequency between high- and low-density treatments were not statistically significant. However, high host density was associated with a lower proportion of males with scrotal testes. Seasonality may have a stronger influence on disease transmission dynamics than host population density, and density effects cannot be considered independent of seasonality.
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delayed density dependent prevalence of sin nombre virus infection in deer mice Peromyscus maniculatus in central and western montana
Journal of Wildlife Diseases, 2011Co-Authors: Scott Carver, Richard J Douglass, Jeremy Trueax, Amy J KuenziAbstract:Understanding how transmission of zoonoses takes place within reservoir populations, such as Sin Nombre virus (SNV) among deer mice (Peromyscus maniculatus), is important in determining the risk of exposure to other hosts, including humans. In this study, we examined the relationship between deer mouse populations and the prevalence of antibodies to SNV, a system where the effect of host population abundance on transmission is debated. We examined the relationship between abundance of deer mice in late summer–early autumn and SNV antibody prevalence the following spring–early summer (termed delayed density-dependent [DDD] prevalence of infection) at both regional and local scales, using 12 live-trapping grids for 11–14 yr, across central and western Montana. When all trapping grids were combined (regional scale), there was a significant DDD relationship for individual months and when months within seasons were averaged. However, within individual grids (local scale), evidence of DDD prevalence of infection was observed consistently at only one location. These findings suggest that, although there is evidence of DDD prevalence of infection at regional scales, it is not always apparent at local scales, possibly because the regional pattern of DDD infection prevalence is driven by differences in abundance and prevalence among sites, rather than in autumn-spring delays. Transmission of SNV may be more complex than the original hypothesis of autumn-spring delayed density dependence suggests. This complexity is also supported by recent modeling studies. Empirical investigations are needed to determine the duration and determinants of time-lagged abundance and antibody prevalence. Our study suggests predicting local, human exposure risk to SNV in spring, based on deer mouse abundance in autumn, is unlikely to be a reliable public health tool, particularly at local scales.
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delayed density dependent prevalence of sin nombre virus antibody in montana deer mice Peromyscus maniculatus and implications for human disease risk
Vector-borne and Zoonotic Diseases, 2007Co-Authors: Nita K Madhav, Kent D Wagoner, Richard J DouglassAbstract:American hantaviruses cause a severe respiratory disease known as hantavirus pulmonary syndrome (HPS). In the United States, Sin Nombre virus (SNV), carried by the deer mouse ( Peromyscus maniculatus), is the etiologic agent in the majority of HPS cases. The relationship between deer mouse population density and SNV infection prevalence in deer mice is poorly understood. Our purpose was to clarify this relationship by demonstrating the existence of delayed-density-dependent prevalence of SNV infection in populations of wild deer mice. We also explored the relationship between SNV infection in deer mouse populations and the incidence of human HPS. The study population was 3,616 deer mice captured on 10 mark-recapture grids in Montana during May and September, 1994–2004. Using multivariate logistic regression analysis, we found a strong association between deer mouse population density in fall (September) and SNV antibody prevalence in deer mice the following spring (May). Other characteristics associated w...
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sin nombre virus in deer mice captured inside homes southwestern montana
Emerging Infectious Diseases, 2000Co-Authors: Amy J Kuenzi, Richard J Douglass, Clifford W BondAbstract:From 1996 through 1999, 35 deer mice (Peromyscus maniculatus) were captured in 25 urban and suburban homes in southwestern Montana. Mice were captured throughout the year except for January; seven mice (20%) from seven (28%) of the homes were seropositive for Sin Nombre virus. The infected mice were mostly adult males captured in the spring and fall.
James N Mills - One of the best experts on this subject based on the ideXlab platform.
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Population Density and Seasonality Effects on Sin Nombre Virus Transmission in North American Deermice (Peromyscus maniculatus) in Outdoor Enclosures
2016Co-Authors: Karoun H Bagamian, Lance A Waller, Amy J Kuenzi, Richard J Douglass, Arlene Alvarado, Brian R Amman, James N MillsAbstract:Surveys of wildlife host-pathogen systems often document clear seasonal variation in transmission; conclusions concerning the relationship between host population density and transmission vary. In the field, effects of seasonality and population density on natural disease cycles are challenging to measure independently, but laboratory experiments may poorly reflect what happens in nature. Outdoor manipulative experiments are an alternative that controls for some variables in a relatively natural environment. Using outdoor enclosures, we tested effects of North American deermouse (Peromyscus maniculatus) population density and season on transmission dynamics of Sin Nombre hantavirus. In early summer, mid-summer, late summer, and fall 2007–2008, predetermined numbers of infected and uninfected adult wild deermice were released into enclosures and trapped weekly or bi-weekly. We documented 18 transmission events and observed significant seasonal effects on transmission, wounding frequency, and host breeding condition. Apparent differences in transmission incidence or wounding frequency between high- and low-density treatments were not statistically significant. However, high host density was associated with a lower proportion of males with scrotal testes. Seasonality may have a stronger influence on disease transmission dynamics than host population density, and density effects cannot be considered independent o
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association between movement and sin nombre virus bunyaviridae hantavirus infection in north american deermice Peromyscus maniculatus in colorado
Journal of Wildlife Diseases, 2013Co-Authors: Brian R Amman, Charles H Calisher, Arie Manangan, Timothy D Flietstra, Darin S Carroll, Kent Wagoner, James N MillsAbstract:Capture data from long-term, mark-recapture studies were used to evaluate movements of North American deermice (Peromyscus maniculatus) on mark-recapture webs in Colorado with respect to Sin Nombre virus (SNV) infection status, age, sex, and trapping site. Latitude and longitude coordinates for each capture during the approximately 12-yr study were used to produce an individual minimum convex polygon (MCP) area representing the movements (not home range) of an individual mouse over time. These MCP areas were compared by SNV infection status (as determined by the presence of antibody), age, and sex. Antibody-negative deermice had significantly larger mean MCP areas than did antibody-positive mice. No differences in MCP area were found between male and female mice (either positive or negative). The smaller MCP areas of antibody-positive mice correspond to decreased movement by SNV-infected deermice on the trapping webs. These findings may indicate that SNV has a negative effect on movement, perhaps by reduc...
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population density and seasonality effects on sin nombre virus transmission in north american deermice Peromyscus maniculatus in outdoor enclosures
PLOS ONE, 2012Co-Authors: Karoun H Bagamian, Lance A Waller, Amy J Kuenzi, Richard J Douglass, James N Mills, Arlene Alvarado, Brian R AmmanAbstract:Surveys of wildlife host-pathogen systems often document clear seasonal variation in transmission; conclusions concerning the relationship between host population density and transmission vary. In the field, effects of seasonality and population density on natural disease cycles are challenging to measure independently, but laboratory experiments may poorly reflect what happens in nature. Outdoor manipulative experiments are an alternative that controls for some variables in a relatively natural environment. Using outdoor enclosures, we tested effects of North American deermouse (Peromyscus maniculatus) population density and season on transmission dynamics of Sin Nombre hantavirus. In early summer, mid-summer, late summer, and fall 2007–2008, predetermined numbers of infected and uninfected adult wild deermice were released into enclosures and trapped weekly or bi-weekly. We documented 18 transmission events and observed significant seasonal effects on transmission, wounding frequency, and host breeding condition. Apparent differences in transmission incidence or wounding frequency between high- and low-density treatments were not statistically significant. However, high host density was associated with a lower proportion of males with scrotal testes. Seasonality may have a stronger influence on disease transmission dynamics than host population density, and density effects cannot be considered independent of seasonality.
Robert S. Lane - One of the best experts on this subject based on the ideXlab platform.
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vector competence of ixodes pacificus and i spinipalpis acari ixodidae and reservoir competence of the dusky footed woodrat neotoma fuscipes and the deer mouse Peromyscus maniculatus for borrelia bissettii
Journal of Medical Entomology, 2003Co-Authors: Lars Eisen, Joseph Piesman, Marc C Dolan, Robert S. LaneAbstract:We investigated the experimental vector competence of Ixodes pacificus Cooley and Kohls and Ixodes spinipalpis Hadwen and Nuttall, and the reservoir competence of the dusky-footed woodrat (Neotoma fuscipes Baird) and the deer mouse (Peromyscus maniculatus [Wagner]), for Borrelia bissettii Postic, Marti Ras, Lane, Hendson, and Baranton. Both rodent species are capable reservoirs for B. bissettii; infection rates for I. pacificus or I. spinipalpis nymphs fed as larvae on infected animals ranged from 50 to 57%. Moreover, both I. pacificus and I. spinipalpis are efficient vectors of B. bissettii. Viable infections were recorded from all rodents known to be exposed to one or more infected nymphs of I. spinipalpis (seven deer mice, two white mice) or I. pacificus (seven deer mice). In contrast, none of four New Zealand white rabbits fed upon by 90 I. pacificus nymphs with a probable B. bissettii infection rate of >50% became infected or seroconverted. The attachment and feeding success of laboratory-reared nymphs similarly confined with deer mice in muslin-covered wire-mesh cages for 24 h ranged from 0% for I. pacificus to 17-73% for I. spinipalpis. Notably, the I. pacificus nymphs were physiologically capable of feeding; nymphs failing to attach to rodents fed readily when placed in feeding capsules upon rabbits. We conclude that the dusky-footed woodrat and the deer mouse are capable experimental reservoir hosts of B. bissettii, and that both I. spinipalpis and I. pacificus are efficient experimental vectors of B. bissettii. However, the reluctance of I. pacificus nymphs to feed on certain rodents may limit its importance as an enzootic vector of B. burgdorferi sensu lato spirochetes.
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vector competence of ixodes pacificus and i spinipalpis acari ixodidae and reservoir competence of the dusky footed woodrat neotoma fuscipes and the deer mouse Peromyscus maniculatus for borrelia bissettii
Journal of Medical Entomology, 2003Co-Authors: Lars Eisen, Joseph Piesman, Marc C Dolan, Robert S. LaneAbstract:Abstract We investigated the experimental vector competence of Ixodes pacificus Cooley and Kohls and Ixodes spinipalpis Hadwen and Nuttall, and the reservoir competence of the dusky-footed woodrat (Neotoma fuscipes Baird) and the deer mouse (Peromyscus maniculatus [Wagner]), for Borrelia bissettii Postic, Marti Ras, Lane, Hendson, and Baranton. Both rodent species are capable reservoirs for B. bissettii; infection rates for I. pacificus or I. spinipalpis nymphs fed as larvae on infected animals ranged from 50 to 57%. Moreover, both I. pacificus and I. spinipalpis are efficient vectors of B. bissettii. Viable infections were recorded from all rodents known to be exposed to one or more infected nymphs of I. spinipalpis (seven deer mice, two white mice) or I. pacificus (seven deer mice). In contrast, none of four New Zealand white rabbits fed upon by 90 I. pacificus nymphs with a probable B. bissettii infection rate of >50% became infected or seroconverted. The attachment and feeding success of laboratory-re...
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transmission of borrelia burgdorferi by ixodes pacificus nymphs and reservoir competence of deer mice Peromyscus maniculatus infected by tick bite
Journal of Parasitology, 1995Co-Authors: Chindi A Peavey, Robert S. LaneAbstract:The transmission of Borrelia burgdorferi to deer mice (Peromyscus maniculatus) by Ixodes pacificus nymphs was investigated experimentally. Deer mice were exposed to infected nymphs for 24, 48, or 72 hr, or until ticks had fed to repletion (> or = 96 hr). Infection status of hosts was assessed 4 wk later by culture of ear-punch biopsies in BSK II medium and by indirect immunofluorescence. Eight mice exposed to ticks for 24 hr did not become Infected. In contrast, infection was acquired by 1 of 9 (11%), 2 of 8 (25%), and 8 of 10 (80%) mice exposed for 48, 72, and > or = 96 hr, respectively. Eight weeks after exposure to infected nymphs, the infectivity of 5 deer mice for I. pacificus larvae was assessed. Overall, 33% of I. pacificus larvae fed on these mice acquired and transstadially passed spirochetes. We conclude that most I. pacificus nymphs require 4 days or longer to transmit spirochetes to deer mice, and that larvae efficiently acquire and maintain spirochetes from mice that have been infected by tick-bite.
Amy J Kuenzi - One of the best experts on this subject based on the ideXlab platform.
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Population Density and Seasonality Effects on Sin Nombre Virus Transmission in North American Deermice (Peromyscus maniculatus) in Outdoor Enclosures
2016Co-Authors: Karoun H Bagamian, Lance A Waller, Amy J Kuenzi, Richard J Douglass, Arlene Alvarado, Brian R Amman, James N MillsAbstract:Surveys of wildlife host-pathogen systems often document clear seasonal variation in transmission; conclusions concerning the relationship between host population density and transmission vary. In the field, effects of seasonality and population density on natural disease cycles are challenging to measure independently, but laboratory experiments may poorly reflect what happens in nature. Outdoor manipulative experiments are an alternative that controls for some variables in a relatively natural environment. Using outdoor enclosures, we tested effects of North American deermouse (Peromyscus maniculatus) population density and season on transmission dynamics of Sin Nombre hantavirus. In early summer, mid-summer, late summer, and fall 2007–2008, predetermined numbers of infected and uninfected adult wild deermice were released into enclosures and trapped weekly or bi-weekly. We documented 18 transmission events and observed significant seasonal effects on transmission, wounding frequency, and host breeding condition. Apparent differences in transmission incidence or wounding frequency between high- and low-density treatments were not statistically significant. However, high host density was associated with a lower proportion of males with scrotal testes. Seasonality may have a stronger influence on disease transmission dynamics than host population density, and density effects cannot be considered independent o
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population density and seasonality effects on sin nombre virus transmission in north american deermice Peromyscus maniculatus in outdoor enclosures
PLOS ONE, 2012Co-Authors: Karoun H Bagamian, Lance A Waller, Amy J Kuenzi, Richard J Douglass, James N Mills, Arlene Alvarado, Brian R AmmanAbstract:Surveys of wildlife host-pathogen systems often document clear seasonal variation in transmission; conclusions concerning the relationship between host population density and transmission vary. In the field, effects of seasonality and population density on natural disease cycles are challenging to measure independently, but laboratory experiments may poorly reflect what happens in nature. Outdoor manipulative experiments are an alternative that controls for some variables in a relatively natural environment. Using outdoor enclosures, we tested effects of North American deermouse (Peromyscus maniculatus) population density and season on transmission dynamics of Sin Nombre hantavirus. In early summer, mid-summer, late summer, and fall 2007–2008, predetermined numbers of infected and uninfected adult wild deermice were released into enclosures and trapped weekly or bi-weekly. We documented 18 transmission events and observed significant seasonal effects on transmission, wounding frequency, and host breeding condition. Apparent differences in transmission incidence or wounding frequency between high- and low-density treatments were not statistically significant. However, high host density was associated with a lower proportion of males with scrotal testes. Seasonality may have a stronger influence on disease transmission dynamics than host population density, and density effects cannot be considered independent of seasonality.
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delayed density dependent prevalence of sin nombre virus infection in deer mice Peromyscus maniculatus in central and western montana
Journal of Wildlife Diseases, 2011Co-Authors: Scott Carver, Richard J Douglass, Jeremy Trueax, Amy J KuenziAbstract:Understanding how transmission of zoonoses takes place within reservoir populations, such as Sin Nombre virus (SNV) among deer mice (Peromyscus maniculatus), is important in determining the risk of exposure to other hosts, including humans. In this study, we examined the relationship between deer mouse populations and the prevalence of antibodies to SNV, a system where the effect of host population abundance on transmission is debated. We examined the relationship between abundance of deer mice in late summer–early autumn and SNV antibody prevalence the following spring–early summer (termed delayed density-dependent [DDD] prevalence of infection) at both regional and local scales, using 12 live-trapping grids for 11–14 yr, across central and western Montana. When all trapping grids were combined (regional scale), there was a significant DDD relationship for individual months and when months within seasons were averaged. However, within individual grids (local scale), evidence of DDD prevalence of infection was observed consistently at only one location. These findings suggest that, although there is evidence of DDD prevalence of infection at regional scales, it is not always apparent at local scales, possibly because the regional pattern of DDD infection prevalence is driven by differences in abundance and prevalence among sites, rather than in autumn-spring delays. Transmission of SNV may be more complex than the original hypothesis of autumn-spring delayed density dependence suggests. This complexity is also supported by recent modeling studies. Empirical investigations are needed to determine the duration and determinants of time-lagged abundance and antibody prevalence. Our study suggests predicting local, human exposure risk to SNV in spring, based on deer mouse abundance in autumn, is unlikely to be a reliable public health tool, particularly at local scales.
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sin nombre virus in deer mice captured inside homes southwestern montana
Emerging Infectious Diseases, 2000Co-Authors: Amy J Kuenzi, Richard J Douglass, Clifford W BondAbstract:From 1996 through 1999, 35 deer mice (Peromyscus maniculatus) were captured in 25 urban and suburban homes in southwestern Montana. Mice were captured throughout the year except for January; seven mice (20%) from seven (28%) of the homes were seropositive for Sin Nombre virus. The infected mice were mostly adult males captured in the spring and fall.
Lars Eisen - One of the best experts on this subject based on the ideXlab platform.
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vector competence of ixodes pacificus and i spinipalpis acari ixodidae and reservoir competence of the dusky footed woodrat neotoma fuscipes and the deer mouse Peromyscus maniculatus for borrelia bissettii
Journal of Medical Entomology, 2003Co-Authors: Lars Eisen, Joseph Piesman, Marc C Dolan, Robert S. LaneAbstract:Abstract We investigated the experimental vector competence of Ixodes pacificus Cooley and Kohls and Ixodes spinipalpis Hadwen and Nuttall, and the reservoir competence of the dusky-footed woodrat (Neotoma fuscipes Baird) and the deer mouse (Peromyscus maniculatus [Wagner]), for Borrelia bissettii Postic, Marti Ras, Lane, Hendson, and Baranton. Both rodent species are capable reservoirs for B. bissettii; infection rates for I. pacificus or I. spinipalpis nymphs fed as larvae on infected animals ranged from 50 to 57%. Moreover, both I. pacificus and I. spinipalpis are efficient vectors of B. bissettii. Viable infections were recorded from all rodents known to be exposed to one or more infected nymphs of I. spinipalpis (seven deer mice, two white mice) or I. pacificus (seven deer mice). In contrast, none of four New Zealand white rabbits fed upon by 90 I. pacificus nymphs with a probable B. bissettii infection rate of >50% became infected or seroconverted. The attachment and feeding success of laboratory-re...
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vector competence of ixodes pacificus and i spinipalpis acari ixodidae and reservoir competence of the dusky footed woodrat neotoma fuscipes and the deer mouse Peromyscus maniculatus for borrelia bissettii
Journal of Medical Entomology, 2003Co-Authors: Lars Eisen, Joseph Piesman, Marc C Dolan, Robert S. LaneAbstract:We investigated the experimental vector competence of Ixodes pacificus Cooley and Kohls and Ixodes spinipalpis Hadwen and Nuttall, and the reservoir competence of the dusky-footed woodrat (Neotoma fuscipes Baird) and the deer mouse (Peromyscus maniculatus [Wagner]), for Borrelia bissettii Postic, Marti Ras, Lane, Hendson, and Baranton. Both rodent species are capable reservoirs for B. bissettii; infection rates for I. pacificus or I. spinipalpis nymphs fed as larvae on infected animals ranged from 50 to 57%. Moreover, both I. pacificus and I. spinipalpis are efficient vectors of B. bissettii. Viable infections were recorded from all rodents known to be exposed to one or more infected nymphs of I. spinipalpis (seven deer mice, two white mice) or I. pacificus (seven deer mice). In contrast, none of four New Zealand white rabbits fed upon by 90 I. pacificus nymphs with a probable B. bissettii infection rate of >50% became infected or seroconverted. The attachment and feeding success of laboratory-reared nymphs similarly confined with deer mice in muslin-covered wire-mesh cages for 24 h ranged from 0% for I. pacificus to 17-73% for I. spinipalpis. Notably, the I. pacificus nymphs were physiologically capable of feeding; nymphs failing to attach to rodents fed readily when placed in feeding capsules upon rabbits. We conclude that the dusky-footed woodrat and the deer mouse are capable experimental reservoir hosts of B. bissettii, and that both I. spinipalpis and I. pacificus are efficient experimental vectors of B. bissettii. However, the reluctance of I. pacificus nymphs to feed on certain rodents may limit its importance as an enzootic vector of B. burgdorferi sensu lato spirochetes.