Distribution and Ecology of Meningeal Worm, Parelaphostrongylus Tenuis (Nematoda), in Northcentral North America

Abstract

Meningeal worm (Parelaphostrongylus tenuis), a common nematode parasite in white-tailed deer (Odocoileus virginianus) and pathogenic for several species of ungulates in eastern North America, is not known to occur in the west. Heads of 1,902 white-tailed deer were examined for adult meningeal worm to determine geographic distribution of the parasite in Saskatchewan and Manitoba (Canada) and North Dakota (USA). Finding the parasite in a deer in eastern Saskatchewan near the Manitoba border established the current northern and western limits in Canada. Prevalence of infection was Ͻ1, 18.6, and 8.2% in Saskatchewan, Manitoba, and North Dakota, respectively. Infected deer occurred throughout southern Manitoba and eastern North Dakota. Distribution appears to have changed little since the last published survey for P. tenuis in the region in 1972. We examined precipitation, temperature, deer density, and forest cover as likely correlates to prevalence and distribution of P. tenuis. Deer management units used for hunting purposes were the scale of analysis in the three jurisdictions. Presence of P. tenuis was positively correlated with precipitation during frost-free periods and deer density, and it was negatively correlated with winter and spring temperatures. Landscapes with Ͼ25 and Ͻ75% forest cover were most likely to have infected deer. Low rainfall and low density of white-tailed deer likely influence the westernmost limit of P. tenuis.

Climate and Habitat Influence Prevalence of Meningeal Worm Infection in North Dakota, Usa

“…Infection was detected in 26 of 38 DMUs, including 14 DMUs where it had not been reported previously. Overall prevalence of infection was 14.5% (95% confidence interval [CI]513.3-15.6%), which was higher than previously reported (8.5%; Wasel et al 2003). Prevalence was lower in fawns (8.7%, 95% CI56.3-11.7%) and yearlings (10.7%, 95% CI59.0-12.5%) than in 2-yr-old and older deer (16.6%, 95% CI515.1-18.2%; x 2 2 532.4, P,0.001).…”

“…In a 1989-91 survey, 45 of 538 (8.5%) whitetailed deer in eastern North Dakota were infected (Wasel et al 2003). We used a Cochran-Mantel-Haenszel test to assess whether the prevalence of meningeal worm infection in …”

“…Seasonal temperature and precipitation influence the range and prevalence of meningeal worm infection via gastropod distribution and larval survival (Lankester and Anderson 1968;Shostak and Samuel 1984;Forrester and Lankester 1998;Wasel et al 2003). We obtained data on precipitation and temperature from 160 weather stations in North Dakota for the period 1963-2005 (National Oceanic and Atmospheric Administration 2015).…”

“…Gastropod abundance is linked to cool, wet microclimates in wooded habitats (Lankester and Anderson 1968;Kearney and Gilbert 1978;Raskevitz et al 1991), and woodlands and croplands in association with woodlands promote abundant white-tailed deer populations (Cote et al 2004;Smith et al 2007). Prevalence of infection is also positively related to growing-season precipitation (Wasel et al 2003); increased growing-season precipitation enhances the ability of habitats to support terrestrial gastropods (Burch 1962;Bickel 1977) and may increase meningeal worm larval survival by helping maintain a moist mucous coating on the outside of deer feces containing larvae (Shostak and Samuel 1984).…”

Towards a Manitoba Hydro boreal woodland caribou strategy: Outcomes from Manitoba Hydro boreal woodland caribou workshop

“…This parasite is common throughout deciduous mixed-hardwood forests of eastern North America, and has been reported as far west as Manitoba (Wasel et al, 2003). While the intermediate host (white-tailed deer) can tolerate the parasite, it is fatal to caribou and may be a contributing factor in declining caribou populations (Thomas, 1995).…”