Projects
Projects
Foot-and-mouth-disease virus (FMDV) can infect over 70 ungulate species, including domestic livestock and numerous wildlife species. Foot-and-mouth disease (FMD) inflicts severe economic losses in endemic countries and is arguably the most important trade-restricting livestock disease in the world. Extreme contagiousness is one of the most striking features of FMDV biology - R0 has been estimated at 20 in buffalo. Following acute infection, most buffalo become carriers, and it has been assumed that transmission from carriers is responsible for ensuring FMDV persistence in buffalo populations. However, most attempts at demonstrating transmission between carrier and susceptible buffalo or cattle under experimental conditions have been unsuccessful. Our recent attempts to affect transmission from carrier buffalo, challenged simultaneously with 3 FMDV serotypes support the apparent inefficiency of transmission by carrier buffalo under experimental conditions. We are currently collaborating with an international team to better understand the ecological and evolutionary factors that allow FMDV persists in wild buffalo populations.
Bighorn sheep populations are threatened by habitat fragmentation and disease spillover from domestic livestock, most notably Mycobacterium ovipneumonia (M. ovi). This study investigates effects of host population isolation on genetic diversity, immunity, susceptibility to infectious disease, and ultimately, population performance in desert bighorn sheep (DBH, Ovis canadensis nelsoni). We take advantage of a current epidemic of ovine pneumonia as a natural experiment to ask (1) How do immunological genotype and phenotype vary with host population isolation?; (2) How does population isolation affect susceptibility to infection?; (3) To what extent will an epidemic of a fatal infection further deplete genetic variation and undermine performance of these fragmented populations?
Infections rarely occur in isolation, and treating one pathogen may have unpredictable effects on another. The Jolles lab, in collaboration with Vanessa Ezenwa at the University of Georgia, studied the effects of deworming on tuberculosis in wild African buffaloes. They expected that because deworming relieves immune suppression, such treatment would lead to a drop in tuberculosis because the animals would clear the second infection without further intervention. Not so. Deworming did improve the lot of parasite-infested individuals, but it also increased the spread of tuberculosis among the population. What apparently happened is that the worm-free buffalo lived longer but stayed infected with tuberculosis and had longer to spread the infection among the herd.
This project examined the health effects of feline immunodeficiency virus (FIV) on African lions (Panthera leo) living in Kruger National Park, South Africa. FIV is an immunosuppressive lentivirus related to human and simian immunodeficiency viruses (HIV and SIV, respectively). It has been linked to AIDS in domestic cats, with derangements of immune cells, blood biochemistry, and secondary infections reflective of the related syndrome seen in humans. While FIV is thought to be less severe in wild felid species, its behavior has not been well characterized, and animals living in free-ranging populations are exposed to a diverse assemblage of pathogens that may bear significant costs for host health. This study focused on immunologic, clinical, and endocrine changes associated with FIV infection in lions. Additionally, we characterized coinfections with native and non-native parasites and pathogens to examine the importance of FIV for lion health and survival.