Campylobacter jejuni is a foodborne pathogen that often leads to human infections through the con... more Campylobacter jejuni is a foodborne pathogen that often leads to human infections through the consumption of contaminated poultry. Wild birds may play a role in the transmission of C. jejuni by acting as reservoir hosts. Despite ample evidence that wild birds harbor C. jejuni, few studies have addressed the role of host ecology in transmission to domestic animals or humans. We tested the hypothesis that host social behavior and habitat play a major role in driving transmission risk. C. jejuni infection and host ecology were studied simultaneously in wild American crows (Corvus brachyrhynchos) in Davis, California over three years. We found that 178 of 337 samples tested were culture-positive (53%), with infection varying by season and host age. Among adult crows, infection was highest during the winter when migrants return and crows form large communal roosts. Nestlings had the highest risk of infection, and whole genome sequencing supports the observation of direct transmission between nestlings. We deployed GPS receivers to quantify habitat use by crows; space use was non-random, with crows preferentially occupying some habitats while avoiding others. This behavior drastically amplified the risk of environmental contamination from feces in specific locations. This study demonstrates that social behavior contributes to infection within species and that habitat use leads to heterogeneous risk of cross species transmission. Campylobacter jejuni is the most common cause of gastroenteritis in industrialized countries. Despite efforts to reduce colonization of poultry flocks and eventual infection of humans, the incidence of human C. jejuni infection has remained high. Because wild birds can harbor strains of C. jejuni that eventually infect humans, there has long been speculation that wild birds might act as an important reservoir in the C. jejuni infection cycle. We simultaneously studied infection prevalence, social behavior, and movement ecology in wild American crows (Corvus brachyrhynchos). We found that social behavior contributed to patterns of infection and that movement behavior resulted in some areas having high risk of transmission while others had low risk. Incorporating ecological data into studies of C. jejuni in wild birds has the potential to resolve when and how wild birds contribute to domestic animal and human C. jejuni infection, leading to better control of initial poultry contamination.
The pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd) has been linked to global decli... more The pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd) has been linked to global declines and extinctions of amphibians, making it one of the most devastating wildlife pathogens known. Understanding the factors that affect disease dynamics in this system is critical for mitigating infection and protecting threatened species. Crayfish are hosts of this pathogen and can transmit Bd to amphibians. Because they co-occur with susceptible amphibian communities, crayfish may be important alternative hosts for Bd. Understanding the prevalence and seasonal dynamics of crayfish infections is of agricultural and ecological interest in areas where crayfish are farmed and traded for human consumption. We conducted a survey of Bd in farmed and natural crayfish (Procambarus spp.) populations in Louisiana, USA. We found that Bd prevalence and infection intensity was low in both farmed and native populations and that prevalence varied seasonally in wild Louisiana crayfish. This seasonal p...
Campylobacter jejuni is a foodborne pathogen that often leads to human infections through the con... more Campylobacter jejuni is a foodborne pathogen that often leads to human infections through the consumption of contaminated poultry. Wild birds may play a role in the transmission of C. jejuni by acting as reservoir hosts. Despite ample evidence that wild birds harbor C. jejuni, few studies have addressed the role of host ecology in transmission to domestic animals or humans. We tested the hypothesis that host social behavior and habitat play a major role in driving transmission risk. C. jejuni infection and host ecology were studied simultaneously in wild American crows (Corvus brachyrhynchos) in Davis, California over three years. We found that 178 of 337 samples tested were culture-positive (53%), with infection varying by season and host age. Among adult crows, infection was highest during the winter when migrants return and crows form large communal roosts. Nestlings had the highest risk of infection, and whole genome sequencing supports the observation of direct transmission between nestlings. We deployed GPS receivers to quantify habitat use by crows; space use was non-random, with crows preferentially occupying some habitats while avoiding others. This behavior drastically amplified the risk of environmental contamination from feces in specific locations. This study demonstrates that social behavior contributes to infection within species and that habitat use leads to heterogeneous risk of cross species transmission. Campylobacter jejuni is the most common cause of gastroenteritis in industrialized countries. Despite efforts to reduce colonization of poultry flocks and eventual infection of humans, the incidence of human C. jejuni infection has remained high. Because wild birds can harbor strains of C. jejuni that eventually infect humans, there has long been speculation that wild birds might act as an important reservoir in the C. jejuni infection cycle. We simultaneously studied infection prevalence, social behavior, and movement ecology in wild American crows (Corvus brachyrhynchos). We found that social behavior contributed to patterns of infection and that movement behavior resulted in some areas having high risk of transmission while others had low risk. Incorporating ecological data into studies of C. jejuni in wild birds has the potential to resolve when and how wild birds contribute to domestic animal and human C. jejuni infection, leading to better control of initial poultry contamination.
The pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd) has been linked to global decli... more The pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd) has been linked to global declines and extinctions of amphibians, making it one of the most devastating wildlife pathogens known. Understanding the factors that affect disease dynamics in this system is critical for mitigating infection and protecting threatened species. Crayfish are hosts of this pathogen and can transmit Bd to amphibians. Because they co-occur with susceptible amphibian communities, crayfish may be important alternative hosts for Bd. Understanding the prevalence and seasonal dynamics of crayfish infections is of agricultural and ecological interest in areas where crayfish are farmed and traded for human consumption. We conducted a survey of Bd in farmed and natural crayfish (Procambarus spp.) populations in Louisiana, USA. We found that Bd prevalence and infection intensity was low in both farmed and native populations and that prevalence varied seasonally in wild Louisiana crayfish. This seasonal p...
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