• Drought reduces chytrid fungus (batrachochytrium dendrobatidis) infection intensity and mortality but not prevalence in adult crawfish frogs (lithobates areolatus)

      Terrell, Vanessa C. K.; Engbrecht, Nathan J.; Pessier, Allan P.; Lannoo, Michael J. (2014)
      To fully understand the impacts of the chytrid fungus Batrachochytrium dendrobatidis (Bd) on amphibians it is necessary to examine the interactions between populations and their environment. Ecologic variables can exacerbate or ameliorate Bd prevalence and infection intensity, factors that are positively related when Bd is acting on naive amphibian populations as an epidemic disease….
    • Duration of maternal antibodies against canine distemper virus and hendra virus in pteropid bats

      Epstein, Jonathan H.; Baker, Michelle L.; Zambrana-Torrelio, Carlos; Middleton, Deborah; Barr, Jennifer A.; DuBovi, Edward; Boyd, Victoria; Pope, Brian; Todd, Shawn; Crameri, Gary; et al. (2013)
      Old World frugivorous bats have been identified as natural hosts for emerging zoonotic viruses of significant public health concern, including henipaviruses (Nipah and Hendra virus), Ebola virus, and Marburg virus. Epidemiological studies of these viruses in bats often utilize serology to describe viral dynamics, with particular attention paid to juveniles, whose birth increases the overall susceptibility of the population to a viral outbreak once maternal immunity wanes. However, little is understood about bat immunology, including the duration of maternal antibodies in neonates. Understanding duration of maternally derived immunity is critical for characterizing viral dynamics in bat populations, which may help assess the risk of spillover to humans. We conducted two separate studies of pregnant Pteropus bat species and their offspring to measure the half-life and duration of antibodies to 1) canine distemper virus antigen in vaccinated captive Pteropus hypomelanus; and 2) Hendra virus in wild-caught, naturally infected Pteropus alecto. Both of these pteropid bat species are known reservoirs for henipaviruses. We found that in both species, antibodies were transferred from dam to pup. In P. hypomelanus pups, titers against CDV waned over a mean period of 228.6 days (95% CI: 185.4–271.8) and had a mean terminal phase half-life of 96.0 days (CI 95%: 30.7–299.7). In P. alecto pups, antibodies waned over 255.13 days (95% CI: 221.0–289.3) and had a mean terminal phase half-life of 52.24 days (CI 95%: 33.76–80.83). Each species showed a duration of transferred maternal immunity of between 7.5 and 8.5 months, which was longer than has been previously estimated. These data will allow for more accurate interpretation of age-related Henipavirus serological data collected from wild pteropid bats.
    • Early-life exposures and Johne’s disease risk in zoo ruminants

      Burgess, Tristan L.; Witte, Carmel L.; Rideout, Bruce (2017)
      Johne’s disease, caused by Mycobacterium avium subsp. paratuberculosis (MAP), is a chronic, progressive bacterial enteritis of ruminants that can cause serious losses in both livestock and exotic species. Infection risk in exotic ruminants is associated with maternal infection status, but the effect of other herdmates on risk of infection has not been reported, to our knowledge....
    • Epidemiology of clinical feline herpesvirus infection in zoo-housed cheetahs (Acinonyx jubatus)

      Witte, Carmel L.; Lamberski, Nadine; Rideout, Bruce; Vaida, Florin; Citino, Scott B.; Barrie, Michael T.; Haefele, Holly J.; Junge, Randall E.; Murray, Suzan; Hungerford, Laura L. (2017)
      OBJECTIVE To determine the incidence of and risk factors for clinical feline herpesvirus (FHV) infection in zoo-housed cheetahs and determine whether dam infection was associated with offspring infection. DESIGN Retrospective cohort study....
    • External reinfection of a fungal pathogen does not contribute to pathogen growth

      DiRenzo, Graziella V.; Tunstall, Tate S.; Ibáñez, Roberto; deVries, Maya S.; Longo, Ana V.; Zamudio, Kelly R.; Lips, Karen R. (2018)
      Chytridiomycosis is an emerging infectious disease of amphibians caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), which has led to devastating declines in amphibian populations worldwide. Current theory predicts that Bd infections are maintained through both reproduction on the host’s skin and reinfection from sources outside of the host....
    • First evidence of amphibian chytrid fungus (Batrachochytrium dendrobatidis) and ranavirus in Hong Kong amphibian trade

      Kolby, Jonathan E.; Smith, Kristine M.; Berger, Lee; Karesh, William B.; Preston, Asa; Pessier, Allan P.; Skerratt, Lee F. (2014)
      The emerging infectious amphibian diseases caused by amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) and ranaviruses are responsible for global amphibian population declines and extinctions. Although likely to have been spread by a variety of activities, transcontinental dispersal appears closely associated with the international trade in live amphibians. The territory of Hong Kong reports frequent, high volume trade in amphibians, and yet the presence of Bd and ranavirus have not previously been detected in either traded or free-ranging amphibians. In 2012, a prospective surveillance project was conducted to investigate the presence of these pathogens in commercial shipments of live amphibians exported from Hong Kong International Airport. Analysis of skin (Bd) and cloacal (ranavirus) swabs by quantitative PCR detected pathogen presence in 31/265 (11.7%) and in 105/185 (56.8%) of amphibians, respectively. In addition, the water in which animals were transported tested positive for Bd, demonstrating the risk of pathogen pollution by the disposal of untreated wastewater. It is uncertain whether Bd and ranavirus remain contained within Hong Kong’s trade sector, or if native amphibians have already been exposed. Rapid response efforts are now urgently needed to determine current pathogen distribution in Hong Kong, evaluate potential trade-associated exposure to free-ranging amphibians, and identify opportunities to prevent disease establishment.
    • Molecular epidemiology of Trypanosomatids and Trypanosoma cruzi in primates from Peru

      Aysanoa, Esar; Mayor, Pedro; Mendoza, A. Patricia; Zariquiey, Carlos M.; Morales, E. Angelo; Pérez, Jocelyn G.; Bowler, Mark; Ventocilla, Julio A.; González, Carlos; Baldeviano, G. Christian; et al. (2017)
      We determined the prevalence rate and risk of infection of Trypanosoma cruzi and other trypanosomatids in Peruvian non-human primates (NHPs) in the wild (n = 126) and in different captive conditions (n = 183). Blood samples were collected on filter paper, FTA cards, or EDTA tubes and tested using a nested PCR protocol targeting the 24S? rRNA gene....
    • Seroepidemiologic survey of potential pathogens in obligate and facultative scavenging avian species in California

      Straub, Mary H.; Kelly, Terra R.; Rideout, Bruce; Eng, Curtis; Wynne, Janna; Braun, Josephine; Johnson, Christine K. (2015)
      Throughout the world, populations of scavenger birds are declining rapidly with some populations already on the brink of extinction. Much of the current research into the factors contributing to these declines has focused on exposure to drug residues, lead, and other toxins. Despite increased monitoring of these declining populations, little is known about infectious diseases affecting scavenger bird species. To assess potential infectious disease risks to both obligate and facultative scavenger bird species, we performed a serosurvey for eleven potential pathogens in three species of scavenging birds in California: the California condor (Gymnogyps californianus), turkey vulture (Cathartes aura) and golden eagle (Aquila chrysaetos). California condors were seropositive for avian adenovirus, infectious bronchitis virus, Mycoplasma gallisepticum, avian paramyxovirus-2, West Nile virus (WNV) and Toxoplasma gondii. Golden eagles were seropositive for avian adenovirus, Chlamydophila psittaci and Toxoplasma gondii, and turkey vultures were seropositive for avian adenovirus, Chlamydophila psittaci, avian paramyxovirus-1, Toxoplasma gondii and WNV. Risk factor analyses indicated that rearing site and original release location were significantly associated with a positive serologic titer to WNV among free-flying condors. This study provides preliminary baseline data on infectious disease exposure in these populations for aiding in early disease detection and provides potentially critical information for conservation of the endangered California condor as it continues to expand its range and encounter new infectious disease threats.
    • The Andean bear alopecia syndrome may be caused by social housing

      Van Horn, Russell C.; Sutherland-Smith, Meg; Sarcos, Andrés E. Bracho; Thomas, Gaylene; Shanks, Jacob A.; Owen, Megan A. (2019)
      The Andean bear alopecia syndrome is a progressive and chronic condition documented in ex situ populations. Recent advances focus on treating symptoms, not preventing future cases. We therefore explored the epidemiology of this syndrome through an analysis of husbandry and veterinary conditions of 63 Andean bears (26M:37F) housed in North and South American zoos and other ex situ circumstances. We had the most complete information for the North American population and found that 29% of females (n = 24) were affected. No males (n = 26) were affected. An analysis of generalized linear models indicated that three models were competitive in describing the occurrence of the condition (i.e., ?AICc ? 2): the model including only the individual's sex (?2 = 13.41, df = 1, p < .001), the model including both individual sex and social housing status (?2 = 1.36, df = 2, p < .001), and the model including both individual sex and the expression of stereotypical behaviors (?2 = 13.82, df = 2, p = .001). Stereotypical behaviors were common among both males (50%, n = 26) and females (51.9%, n = 27) whether or not they were affected, but the syndrome was seen only in females who had been socially housed. Therefore, we suggest that the Andean bear alopecia syndrome is a symptomatic response to the long-term social housing of bears that would otherwise not live socially. To prevent new cases, we recommend that female Andean bears be housed with adult conspecifics only when females choose to cohabitate.