Prevalence of filarioid nematodes and trypanosomes in American robins and house sparrows, Chicago USA.

Hosts are commonly infected with a suite of parasites, and interactions among these parasites can affect the size, structure, and behavior of host-parasite communities. As an important step to understanding the significance of co-circulating parasites, we describe prevalence of co-circulating hemoparasites in two important avian amplification hosts for West Nile virus (WNV), the American robin (Turdus migratorius) and house sparrow (Passer domesticus), during the 2010-2011 in Chicago, Illinois, USA. Rates of nematode microfilariemia were 1.5% of the robins (n = 70) and 4.2% of the house sparrows (n = 72) collected during the day and 11.1% of the roosting robins (n = 63) and 0% of the house sparrows (n = 11) collected at night. Phylogenetic analysis of nucleotide sequences of the 18S rRNA and cytochrome oxidase subunit I (COI) genes from these parasites resolved two clades of filarioid nematodes. Microscopy revealed that 18.0% of American robins (n = 133) and 16.9% of house sparrows (n = 83) hosted trypanosomes in the blood. Phylogenetic analysis of nucleotide sequences from the 18s rRNA gene revealed that the trypanosomes fall within previously described avian trypanosome clades. These results document hemoparasites in the blood of WNV hosts in a center of endemic WNV transmission, suggesting a potential for direct or indirect interactions with the virus.

Chronology and development of juvenile bluegill parasite communities.

This study describes the parasite communities of juvenile bluegill and examines the development of parasite communities in juvenile bluegill from 2 Michigan lakes. Parasitological examination of 510 juvenile bluegill from 2 Michigan lakes (Three Lakes II [TL] and Gull Lake [GL]) demonstrated that TL bluegill harbored 19 parasite species and GL bluegill harbored 16 parasite species. Parasite communities of juvenile bluegill from both lakes were dominated by larval parasites, particularly larval trematodes. A nonmetric multidimensional scaling analysis showed bluegill of similar lengths to have similar parasite communities. Relative influences of species richness on parasite infracommunities of juvenile bluegill suggest similar patterns of parasite community structure between TL and GL. Patterns in parasite colonization evident in both lakes suggest that the smallest juvenile bluegill are primarily vulnerable to colonization by parasites acquired through direct contact, particularly larval trematodes, while the majority of parasites acquired through ingestion are not acquired until juvenile bluegill are larger and less-gape limited.

New species of Freitascapillaria (Nematoda: Capillariidae) from the intestine of Cottus caeruleomentum (Teleostei: Cottidae) in Maryland.

A new species of capillariid nematode, Freitascapillaria laticauda n. sp. (Capillariidae), is described from the intestine of the blue ridge sculpin, Cottus caeruleomentum (Cottidae, Scorpaeniformes) from the Blue Lick Run, Maryland, United States. It differs from its congeners mainly in the body length (male 3.1-5.4 mm, female 7.0-11.1 mm), the length of the male esophagus (1.5-2.9 mm) and spicule (42-45 microm), and the size of eggs (60-66 x 27-33 microm). Previous records of Freitascapillaria spp. were from characid, poeciliid, and cyprinid fishes in Brazil, Neotropical Mexico, and China, respectively, so that F. laticauda n. sp. is the first species of this genus reported from Nearctic North America and from a scorpaeniform fish.

Parasites of juvenile brook trout (Salvelinus fontinalis) from Hunt Creek, Michigan.

Four parasite species (Crepidostomum cooperi, Cystidicoloides ephemeridarum, Acanthocephalus dirus, Salmincola edwardsii) infected 215 juvenile brook trout (105 young-of-year; 110, 1-yr-old) from Hunt Creek, Michigan, in 2003, 2004, and 2005. Prevalences of these species in 2004 (main study year) varied from 29 to 37%. Crepidostomnum cooperi had the highest mean intensity and mean abundance, followed by C. ephemeridarum. The number of fish infected with each parasite species was significantly higher in 1-yr-old fish than in young-of-year fish. Also, the mean intensities and mean abundances of C. cooperi and C. ephemeridarum and the mean abundance of A. dirus were significantly higher in older fish. The mean intensity of C. cooperi and prevalence of A. dirus were significantly higher in fish between creek sections. Fish length had a significant positive effect on the abundances of C. cooperi and C. ephemeridarum; parasite species richness, on the abundances of A. dirus and S. edwardsii; and parasite species richness in the 2003 and 2004 trout cohorts, respectively. Crepidostomum cooperi, C. ephemeridarum, A. dirus, and S. edwardsii commonly infect Michigan brook trout. The small number of parasite species infecting Hunt Creek brook trout is similar to the number of parasite species of brook trout from other Michigan creeks.

Helminths of pond-reared walleye from Wisconsin.

One hundred extended growth walleye fingerlings, Sander vitreus (Percidae), collected on 6 October 2004, from 1 rearing pond at the Lake Mills State Fish Hatchery in Lake Mills, Wisconsin, were examined for parasites. Diplostomum sp. (Trematoda: Diplostomatidae), Contracaecum sp. (Nematoda: Anisakidae), Bothriocephalus cuspidatus (Cestoda: Bothriocephalidae), and Proteocephalus sp. (Cestoda: Proteocephalidae) were the only parasites found. The first 3 species occurred as larval stages. Diplostomum sp. and Contracaecum sp. had similar prevalences, mean intensities, and mean abundances (72%, 2.2, and 1.6 and 71%, 2.1, 1.5, respectively) in walleye fingerlings. A headlamp technique used by the Wisconsin Department of Natural Resources personnel generated a prevalence of Diplostomum sp. in the lens that overestimated the prevalence of Diplostomum sp. found in a random subsample of 100 fingerlings examined with a microscope. Proteocephalus sp. and B. cuspidatus infected 14 and 12 fingerlings, respectively.

Ubiquitous variability in the prevalence of Trichobilharzia stagnicolae (Schistosomatidae) infecting Stagnicola emarginata in three northern Michigan lakes.

During 4 consecutive collecting seasons from 1998 through 2001, 77,326 common beach snails (Stagnicola emarginata, Lymnaeidae) were examined for infections by Trichobilharzia stagnicolae from multiple sites on Walloon Lake, Higgins Lake, and Lake Leelanau, located in the northern region of the lower peninsula of Michigan. Snails were examined for infections using the light-box technique (exposure to bright fluorescent light). The prevalence of infected snails varied significantly among lakes within a year, between years in a lake, at a site from year to year, and at a site over a collecting season. Overall annual prevalence ranged from 0.54% (1999) to 1.32% (2001) on Walloon Lake, from 0.56% (2001) to 1.06% (1998) on Higgins Lake, and 0.30% (2001) to 0.89% (2000) on Lake Leelanau. Generally, the peak in prevalence coincided in July on the lakes. Prevalence was found to increase with snail length in all lakes. A comparison of the light-box technique and crushing snails demonstrated that prevalence varied in magnitude by technique as much as 1.2 and 5.7 times.

Occurrence of acanthocephalans in largemouth bass and smallmouth bass (Centrarchidae) from Gull Lake, Michigan.

A total of 65 largemouth bass, Micropterus salmoides, and 27 smallmouth bass, M. dolomieu, collected in April-September 2000 and April-July 2001 from Gull Lake, Michigan, were examined for acanthocephalans. Leptorhynchoides thecatus and Neoechinorhynchus cylindratus infected all the bass examined. Leptorhynchoides thecatus had the highest mean intensity (258.2 +/- 185.4 in 2000 and 145.0 +/- 61.0 in 2001) of the species infecting smallmouth bass. Although N. cylindratus had higher mean intensities (42.1 +/- 37.9 in 2000 and 68.9 +/- 70.5 in 2001) than did L. thecatus in largemouth bass, the values were not significantly different between bass species. The prevalence, mean intensity, and mean abundance of Pomphorhynchus bulbocolli in the bass species were below the values for the other acanthocephalan species. Leptorhynchoides thecatus and N. cylindratus are the most abundant intestinal helminths in bass from Gull Lake.

Occurrence of Ergasilus megaceros Wilson, 1916, in the sea lamprey and other fishes from North America.

Ergasilus megaceros (Copepoda: Ergasilidae) was recovered from the nasal fossae (lamellae) of the olfactory sac in 1 (1.8%) of 56 sea lampreys, Petromyzon marinus Linne, 1758, collected in May 2002 from the Cheboygan River, Michigan. Although the sea lamprey is a new host record for E. megaceros, this fish species may not be a preferred host because of its low prevalence. Ergasilus megaceros is the second ergasilid species reported from the sea lamprey in North America. This is the third report of an ergasilid species infecting the nasal fossae of fishes in North America, with E. rhinos being the only other species reported from this site.

Occurrence of Bunodera sacculata Van Cleave and Mueller, 1932 in Perca flavescens from Silver Creek and Silver Lake, Michigan.

Bunodera sacculata (Trematoda: Allocreadiidae) infected 65 (54%) of 120 yellow perch collected in 1997 and 40 (50%) of 80 perch from Silver Creek in 1998. and 17 (30%) of 56 perch in 2000 from Silver Lake in lower Michigan. Gravid B. sacculata occurred in the pyloric ceca and anterior intestine. There were differences in monthly trends (July through August) in prevalences, mean intensities, and mean abundances of B. sacculata in Silver Creek between 1997 and 1998. The mean intensity +/- SD (8.2 +/- 9.1) and mean abundance (4.1 +/- 7.8) of B. sacculata were significantly higher in 1998 than in 1997 and 2000. An additional 20 perch (0+ in age) collected from the creek in July 1998 were all infected and had the highest mean intensity of 21.3 +/- 14.1.