Prevalence of Antibodies Against Toxoplasma gondii in Polar Bears (Ursus maritimus) From Svalbard and East Greenland

Abstract

Serum samples from 419 polar bears (Ursus maritimus) from Svalbard and the Barents Sea (collected 1990-2000) and 108 polar bears from East Greenland (collected 1999-2004) were assayed for antibodies against Toxoplasma gondii using the modified agglutination test. Antibody prevalences were 3.6% among cubs dependent on their mothers and 21.4% among subadults and adults. Among subadults and adults there was an interaction between population and sex, with similar prevalences among females (Svalbard = 19.5%, Greenland = 18.0%), but a high frequency among Svalbard males (28.7%) as compared to Greenland males (5.8%). The pattern was also significant after correcting for differences in age distribution. The sex-population interaction term is believed to be connected to area- and sex-specific feeding ecology. The prevalences of antibodies against T. gondii in Svalbard and Greenland were high compared to previously reported findings in polar bears from Russian and Alaskan areas.

Morbillivirus and Toxoplasma Exposure and Association with Hematological Parameters for Southern Beaufort Sea Polar Bears: Potential Response to Infectious Agents in a Sentinel Species

“…Although incidence of clinical toxoplasmosis among marine mammals appears low, antibodies to the parasite have been detected in numerous species across the Arctic (Tryland, 2000). Seroprevalence for Alaskan polar bears was 6% (Rah et al, 2005), and in Svalbard and Greenland, polar bears ranged from 3.6% to 28.7% depending upon age, sex, and location (Oksanen et al, 2009). Antibodies to T. gondii occur in several species sharing habitat with polar bears in Alaska including: walrus (Obobenus rosmarus), bearded seals (Erignathus barbatus), spotted seals (Phoca largha), and ringed seals (Dubey et al, 2003); grizzly bears (Zarnke et al, 2000); wolves, and caribou (Rangifer tarandus) (Zarnke et al, 1997); and in Canada: hooded (Cystophora cristata) and gray seals (Halichoerus grypus) (Measures et al, 2004).…”

“…Antibodies to morbillivirus and Toxoplasma gondii have been previously documented in polar bears throughout the Arctic (Garner et al, 2000;Tryland, 2000;Tryland et al, 2005;Cattet et al, 2004;Zarnke et al, 2004;Rah et al, 2005;Oksanen et al, 2009;Jensen et al, 2010). Transmission dynamics of morbilliviruses and Toxoplasma in the Arctic may be affected as climate changes impact vectors and the health, behavior, movement, and population dynamics of reservoir populations of marine (e.g., pinniped) and terrestrial hosts (e.g., domestic and wild canids).…”

Effects of climate warming on polar bears: a review of the evidence

“…Developing cubs may be particularly vulnerable to pollutants that are known to affect a variety of physiological processes in polar bears such as immune function, endocrine levels, organ development, and bone density (see review in Sonne, 2010). While limited evidence to support increased disease exists, exposure of polar bears to Toxoplasma gondii, a protozoan parasite, in the Svalbard area doubled in recent years (Oksanen et al, 2009;Jensen et al, 2010). The increase was postulated to be linked to an influx of temperate marine invertebrates acting as vectors, or an influx of warmer waters (Jensen et al, 2010), although the possible effects of the parasite are unknown.…”

Barents Sea polar bears (Ursus maritimus): population biology and anthropogenic threats

“…Baseline levels of occurrence of pathogens such as Brucella, Toxoplasma and viruses have been documented in polar bears from the Svalbard area (Tryland et al 2001;Tryland et al 2005;Oksanen et al 2009;Å sbakk et al 2010;Jensen et al 2010), but long-term monitoring and the effects of disease in a multi-stressor analysis have not yet been established.…”