Spatial and Temporal Patterns of Trichinella in Montana’s Black Bears, 2004-2014

Trichinella nematodes are a globally distributed, zoonotic parasite transmitted through the consumption of infected animal tissue. Humans are at risk of contracting Trichinella by consuming undercooked bear or mountain lion meat, and thus historically, Montana Fish, Wildlife, and Parks subsidized Trichinella-testing of hunter-harvested black bears (Ursus americanus) and mountain lions (Puma concolor). Here, we summarize 11 years of data (2004-2014) on the spatial and temporal distribution of Trichinella in Montana’s black bears. Risk of infection was spatially variable, highest in northwest Regions 1 and 4, and was positively associated with black bear and grizzly bear (Ursus arctos horrobilis) densities. Prevalence has been significantly declining across the state over time from a state-wide prevalence of 0.05 in 2004 to 0.02 in 2014. Potential causes and consequences are discussed.  Montana Fish, Wildlife, and Parks stopped subsidizing Trichinella testing in 2015; hunters are asked to thoroughly cook their meat to an internal temperature of 165° F, which inactivates Trichinella species and most other parasites

Coevolution and Biogeography Among Nematodirinae (Nematoda: Trichostrongylina) Lagomorpha and Artiodactyla (Mammalia): Exploring Determinants of History and Structure for the Northern Fauna Across the Holarctic

Nematodes of the subfamily Nematodirinae are characteristic components of a Holarctic fauna. the topology of a generic-level phylogenetic hypothesis, patterns of diversity, and geographic distributions for respective nematode taxa in conjunction with data for host occurrence are consistent with primary distributions determined across Beringia for species of Murielus, Rauschia, Nematodirus, and Nematodirella. Ancestral ghosts are represented by Lagomorpha, with evidence for a minimum of 1 host-switching-event and subsequent radiation in the Artiodactyla. Diversification may reflect vicariance of respective faunas along with episodic or cyclical range expansion and isolation across Beringia during the late Tertiary and Quaternary. Secondarily, species of Nematodirus molini among tayassuids, Nematodirus lamae among camelids and Nematodirus urichi in cervids during the Pleistocene. Nematodirines are a core component of an Arctic-Boreal fauna of zooparasitic nematodes (defined by latitude and altitude) adapted to transmission in extreme environments characterized by seasonally low temperatures and varying degrees of desiccation. The history and distribution of this fauna is examined in the context of host-parasite systems to ecological perturbation under a regime of global climate change

Global distribution of alveolar and cystic echinococcosis

Alveolar echinococcosis (AE) and cystic echinococcosis (CE) are severe helminthic zoonoses. Echinococcus multilocularis (causative agent of AE) is widely distributed in the northern hemisphere where it is typically maintained in a wild animal cycle including canids as definitive hosts and rodents as intermediate hosts. The species Echinococcus granulosus, Echinococcus ortleppi, Echinococcus canadensis and Echinococcus intermedius are the causative agents of CE with a worldwide distribution and a highly variable human disease burden in the different endemic areas depending upon human behavioural risk factors, the diversity and ecology of animal host assemblages and the genetic diversity within Echinococcus species which differ in their zoonotic potential and pathogenicity. Both AE and CE are regarded as neglected zoonoses, with a higher overall burden of disease for CE due to its global distribution and high regional prevalence, but a higher pathogenicity and case fatality rate for AE, especially in Asia. Over the past two decades, numerous studies have addressed the epidemiology and distribution of these Echinococcus species worldwide, resulting in better-defined boundaries of the endemic areas. This chapter presents the global distribution of Echinococcus species and human AE and CE in maps and summarizes the global data on host assemblages, transmission, prevalence in animal definitive hosts, incidence in people and molecular epidemiology