Decreased seroprevalence for Toxoplasma gondii in Seventh Day Adventists in Maryland.

Despite its widespread prevalence, uncertainties remain about the relative contribution of various routes of transmission to the overall rate of infection with Toxoplasma gondii, particularly in developed countries. To explore the hypothesis that meat consumption is an important risk factor for infection, a cross-sectional seroprevalence study was performed on healthy adults in one region in the state of Maryland. The population included Seventh Day Adventists who as a group follow a diet containing no meat, and control community volunteers who were not Seventh Day Adventists. Thirty-one percent of the population had serologic evidence of T. gondii infection. People with T. gondii infection were older (49 versus 42 years old; P < 0.01, by t-test) and less likely to be Seventh Day Adventists (24% versus 50%; P < 0.01, by chi-square test) than people without T. gondii infection. When adjustments were made for age and gender through multiple logistic regression, Seventh Day Adventists had a significantly decreased risk of T. gondii infection (odds ratio = 0.21, 95% confidence interval = 0.09-0.46, P = 0.0001) compared with the controls. While the basis for this effect remains to be determined, one possible protective factor is the general adherence of Seventh Day Adventists to a diet that does not contain meat.

Prehistoric parasitism in Tennessee: evidence from the analysis of desiccated fecal material collected from Big Bone Cave, Van Buren County, Tennessee.

Eight samples of desiccated human feces collected from Big Bone Cave (40VB103), Van Buren County, Tennessee, were analyzed to determine the presence of ecto- and endoparasitic infection among the prehistoric population using the cave. Radiocarbon-dated torch material from the cave indicated that it was a locus of human activity 2,177 +/- 145 yr ago. Parasitic species identified were: Ascaris lumbricoides, Enterobius vermicularis, fleas of the tribe Phalacropsyllini, and protozoan cysts. The cysts were identified as Giardia using an indirect immunofluorescent antibody test. The only report of Giardia in a prehistoric context is the identification of cysts in 2 1,800-yr-old paleofecal specimens from a cave in Israel. This is the first report of Giardia from paleofeces in the New World.

Angiocaulus gubernaculatus in the island fox (Urocyon littoralis) from the California Channel Islands and comments on the diagnosis of angiostrongylidae nematodes in canid and mustelid hosts.

Adult nematode parasites were recovered from the heart blood of a deceased island fox (Urocyon littoralis) submitted for necropsy to determine the cause of death. Examination of the recovered nematodes supported the generic diagnosis of Angiocaulus, a parasite in Angiostrongylidae found in domestic and wild canids and mustelids. Specific diagnosis of the worms from the island fox as Angiocaulus gubernaculatus is based on the morphology of the dorsal ray in the copulatory bursa of the male worm and its comparison with published descriptions of Angiocaulus raillieti and A. gubernaculatus. Although A. gubernaculatus has been typically associated with mustelid hosts, its occurrence in the island fox indicates that the host distribution for the parasite may not be as restricted as previously believed.

Archeological evidence of parasitic infection from the 19th century company town of Fayette, Michigan.

Archeological deposits from the 19th century company town of Fayette, Michigan were analyzed for evidence of endoparasitic infection in the human population residing in the town between 1867 and 1891. Three privies were associated with upper-income and middle-income neighborhoods; 2 household refuse disposal areas were found in a predominately lower-income immigrant working class neighborhood. Sediment samples from 2 privies associated with dwellings in the middle-income neighborhood were positive for eggs of the human whipworm Trichuris trichiura. The parasite was probably also present among residents of the lower income neighborhood, but the shallow nature of the refuse deposits in that locality precluded preservation of the eggs. Contemporary epidemiologic studies of helminth infections support the belief that T. trichiura may have been a common parasite of 19th century school-age children given the natural inclination of young children to defecate indiscriminately, play freely in the dirt, and eat without washing their hands.

Prevalence of Dirofilaria immitis and Dipetalonema reconditum infection in dogs: 805 cases (1980-1989).

Clinical records of 6,977 dogs examined at the small animal clinic of the University of Tennessee College of Veterinary Medicine from January 1980 through December 1989 were analyzed to determine the prevalence and changing frequency of Dirofilaria immitis and Dipetalonema reconditum infection. Using the Knott's test on these dogs, 805 (11.54%) tested positive for microfilariae, with D immitis in 430 dogs (6.16%), and Dip reconditum in 375 dogs (5.37%). Statistical analysis confirmed that the prevalence of D immitis and that of Dip reconditum were essentially equal in the population of dogs included in this study. There was a slight decrease in the prevalence of D immitis over the 10 years examined, but the prevalence of Dip reconditum remained constant. The results were not affected by year-to-year variability in the number of examinations performed. On the basis of our findings, in eastern Tennessee, those veterinarians who diagnose heartworm infection by the presence of microfilariae without differentiating the species involved, risk misdiagnosing 50% of the cases. If the patterns of prevalence seen in recent years continue, the chances of error may actually increase.

Comparison of the efficacies of three heartworm preventives against experimentally induced infections with Ancylostoma caninum and Toxocara canis in pups.

Forty 11- to 12-week-old helminth-naive Beagles were categorized by sex and weight and randomly assigned to 4 treatment groups (group 1, ivermectin/pyrantel pamoate; group 2, milbemycin oxime; group 3, untreated control; group 4, diethylcarbamazine/oxibendazole). Each pup was inoculated PO with approximately 100 infective Ancylostoma caninum larvae and 100 larvated Toxocara canis eggs on day 0, and repeatedly at 7-day intervals thereafter until day 56. Administration of anthelmintics also began on day 0, and subsequent treatments were administered according to label recommendations at 30-day intervals (groups 1 and 2) or daily (group 4) for a period of 90 consecutive days. Body weight and A caninum and T canis fecal egg counts were measured at weekly intervals, and clinical observations of health status were conducted twice daily. Pups were euthanatized on day 90, and total gastrointestinal worm burdens were determined. Compared with mean A caninum egg counts of group-3 control pups, egg counts in group-1 pups were significantly (P < or = 0.0001) lower on every sampling days 35, 42, 49, 63, 70, 77, and 84, and were consistently the highest of all treated groups, and egg counts of group-4 pups were significantly (P < or = 0.0001) lower on every sampling date from day 14 to day 90, and were consistently the lowest of all treated groups. Compared with mean A caninum egg counts of group-3 pups, egg counts in group-1 and group-2 pups were lower by 97.8 and 90.8%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of rainfall, host demography, and musth on strongyle fecal egg counts in African elephants (Loxodonta africana) in Namibia.

Wild African elephants (Loxodonta africana) are commonly infected with intestinal strongyle parasites. Our objective was to determine baseline fecal strongyle egg counts for elephants in the northeast region of Etosha National Park, Namibia and determine if these numbers were affected by annual rainfall, elephant demography (age of individuals and composition of groups), and hormonal state of males. We found that matriarchal family group members have significantly higher fecal egg counts than male elephants (bulls). Among family group members, strongyle egg counts increased with age, whereas among bulls, strongyle egg counts decreased with age. Years of higher rainfall were correlated with decreased numbers of strongyle eggs among bulls. Finally, bulls were not affected by their physiologic (hormonal) status (musth vs. nonmusth). These results suggest that infection by strongyle parasites in Namibian African elephants is a dynamic process affected by intrinsic and extrinsic factors including host demography and rainfall.