Fig 1.
Wolf seroprevalence to B. burgdorferi, A. phagocytophilum, E. canis, and D. immitis by age group in Wisconsin during 1985 to 2011.
Pup represents individuals between 0 and 1 year old, yearling between 1 and 2 years old and adult are individuals older than 2 years old. Asterisks represent significant differences (P<0.05) compared to pups. Sample size for pup = 99–101, yearling = 62–63, adult = 207–210 depending on the disease.
Fig 2.
Temporal trend in wolf seroprevalence to B. burgdorferi and E. canis in Wisconsin during 1985 to 2011.
For both pathogens years were grouped into the following 5 groups: 1985–1990 (n = 13), 1991–1996 (n = 40), 1997–2001 (n = 62), 2002–2006 (n = 109 and 108 for B. burgdorferi and E. canis, respectively), and 2007–2011 (n = 148 and 147 for B. burgdorferi and E. canis, respectively). Data points represent the observed prevalence of wolf exposure within a period. Vertical bars represent 95% confidence interval (CI). Coefficient estimate for B. burgdorferi = -0.05 (P = 0.03, 95% CI = 0.0–0.09, Odds Ratio = 1.05, 95% CI = 1.0–1.05). Coefficient estimate for E. canis = -0.09 (P = 0.026; CI = -0.16 –-0.01, Odds Ratio = 0.92, CI = 0.85–0.99).
Table 1.
Parameter estimates for logistic regression models of seroprevalence to Borrelia burgdorferi, Anaplasma phagocytophilum, and Dirofilaria immitis.
Table 2.
Parameter estimates for logistic regression models of seroprevalence to Ehrlichia canis.
Fig 3.
Spatial distribution of clusters of wolf seroprevalence to B. burgdorferi (1985–2011) and domestic dogs (2007–2013), and human cases (1989–2011) in Wisconsin.
The maps show the location and extent of the most likely cluster and secondary clusters of seroprevalence and the counties encompassed by it are shaded. In addition, the log likelihood ratio (LLR), relative risk (RR), significance (P-value), expected number of cases (Expected) and observed number of cases (Observed) are shown for each cluster.
Fig 4.
Seroprevalence of gray wolves to B. burgdorferi (Lyme disease) during 1985 to 2011, and incidence of human Lyme disease from 1989 through 2011, within spatial cluster of exposure located in northwestern Wisconsin.
Wolf samples are grouped into 5-year groups (1985–1990 (n = 4), 1991–1996 (n = 18), 1997–2001 (n = 26), 2002–2006 (n = 52) and 2007–2011 (n = 69)). Data points represent the observed prevalence of wolf exposure within a period. Vertical bars represent 95% confidence interval (CI). Coefficient estimate = 0.07 (z = 1.71, P = 0.09, 95% CI = -0.01–0.15, OR = 1.07, CI = 0.99–1.17). For human Lyme disease incidence the coefficient estimate = 4.18 (t = 7.067, P< 0.001, 95% CI = 2.95–5.42).