Blood Parasites of Blue-winged Teal ( Anas discors ) from Two Migratory Corridors, in the Southern USA.

We collected 180 Blue-winged Teal ( Anas discors ) in September and October 2002 from Florida, US (n=100, representing the eastern migratory corridor) and the Louisiana-Texas, US, border (n=80, representing the western migratory corridor) and examined for blood parasites using thin heart-blood smears. Leucocytozoon simondi, Haemoproteus nettionis, and microfilariae were found in 16, 23, and 27 birds, respectively. Prevalence of L. simondi and H. nettionis did not vary by migratory corridor, but the prevalence of microfilariae was higher in the western corridor (23%) than the eastern corridor (9%). No differences in prevalence of L. simondi, H. nettionis, and microfilariae were observed by host age or sex. The mean density of L. simondi and H. nettionis averaged 1.5±0.3 and 2.3±0.4 (±SE per 3,000 erythrocytes), respectively. Ranked abundance models for main and interactive effects of corridor, age, and sex were not statistically significant for L. simondi or H. nettionis. Low prevalence and abundance of hematozoa in early autumn migrants reflects the likelihood of low exposure probabilities of Blue-winged Teal on the breeding grounds, compared to their congeners.

Helminth Community Dynamics in Populations of Blue-Winged Teal (Anas discors) Using Two Distinct Migratory Corridors.

The influence of spatially distinct host subpopulations on helminth community structure and pattern was examined in a migratory avian host species. Forty helminth species represented by 24,082 individuals were collected from 184 blue-winged teal (Anas discors; BWT) from 2 primary migratory corridors in Florida (eastern migratory corridor; EMC) and Louisiana and Texas (western migratory corridor; WMC). Mean species richness was greater in BWT from the WMC (x̅±SE = 10.2 ± 0.3 species) than the EMC (8.6 ± 0.2). The helminth community from the WMC had higher abundances of 6 common/intermediate species. Corridor helminth communities were similar in species composition but less similar when incorporating abundances of those species. Overlapping distributions of phylogenetically related host species that share generalist helminth species across ecologically similar habitats seem to mitigate the isolating mechanisms that are necessary for the distinct coevolutionary pathways to develop between adjacent corridors.

Two new species of Sarcocystis (Apicomplexa: Sarcocystidae) infecting the wolverine (Gulo gulo) from Nunavut, Canada.

Infection with Sarcocystis species is common in many species of animals, but it has not yet been reported in wolverines (Gulo gulo). Histological sections of tongues from 41 wolverines in the Kitikmeot Region, Nunavut, Canada, were examined for sarcocysts. Sarcocysts were found in 33 (80.4%) wolverines. Two structurally distinct types of sarcocysts were found. Type A sarcocysts were thin (<1 µm thick) walled. Ultrastructurally, the parasitophorous vacuolar membrane (Pvm) had minute undulations, but it lacked villar protrusions and was not invaginated into the granular layer. The bradyzoites were slender, about 5 × 1 µm in size. Structurally, these sarcocysts were distinct from known species of Sarcocystis and possessed a novel 18S and ITS-1 sequence, sharing 98% and 78% sequence similarity with Sarcocystis canis . A new species name, Sarcocystis kalvikus, is proposed for type A sarcocysts. In contrast, type B sarcocysts had relatively thicker (about 2 µm) cyst walls and larger bradyzoites, each about 10 × 2-3 µm. Ultrastructurally, the Pvm on the sarcocyst wall had villar protrusions that were either mushroom-like or sloping. Molecular analysis identified a unique 18S and ITS-1 sequence that placed them in a clade within the Sarcocystidae. Based on histology, TEM, and genetic data, the new name, Sarcocystis kitikmeotensis, is proposed. Sarcocystis kalvikus was found in 14 (34.1%), S. kitikmeotensis was found in 7 (17%), and both species were found in 12 (29.2%) of 41 wolverines.

Prevalence of antibodies to Toxoplasma gondii in wolverines from Nunavut, Canada.

The prevalence of antibodies to Toxoplasma gondii was determined in blood and tissue exudates recovered from the spleens of 41 wolverines (Gulo gulo) collected in Nunavut, Canada, using a modified agglutination test (MAT). Antibodies to T. gondii were found in 17 (41.5%) of the 41 wolverines with MAT titers of 1:25 in 1, 1:50 in 4, 1:100 in 5, 1:200 in 6, and 1:400 in 1. This is the first report of antibodies to T. gondii in wolverines, and the results indicate that exposure is common.

Trichinella T6 and Trichinella nativa in Wolverines (Gulo gulo) from Nunavut, Canada.

Infection of Trichinella spp. is common among animals in the Canadian Arctic. We determined the prevalence of Trichinella spp. infection in wolverines (Gulo gulo) from Nunavut, Canada. Diaphragms from 41 wolverines were examined by artificial digestion. Trichinella spp. larvae were detected in 36 (87.8%) examined animals. Trichinella T6 was detected in 33 (91.7%), Trichinella nativa in only one (2.8%), and a mixed Trichinella T6 and T. nativa infections were detected in two (5.6%) wolverines. This is the first report of Trichinella spp. infection in wolverines from Nunavut and the first report of sympatric Trichinella T6 and T. nativa in any host. The high prevalence of Trichinella spp. infection in combination with the natural history of wolverines suggests that the mustelid may be a key species in the natural cycle of these parasites in Arctic and Subarctic areas.