Trichuris sp. and Strongyloides sp. infections in a free-ranging baboon colony.

We conducted cross-sectional surveys of parasites infecting a large free-living colony of baboons at the Southwest National Primate Research Center in San Antonio in October 2003 and April 2004, immediately before, and 6 mo after, treatment with ivermectin. Trichuris sp. was the predominant species present, infecting 79 and 69% of individual animals in the 2 surveys, with fecal egg counts (FEC) of up to 60,200 eggs per g (epg) (mean = 1,235 in October 2003 and 1,256 in April 2004). Prevalence remained fairly stable across age groups, and intensity was highest in animals <1 or >15 yr old, in contrast to patterns observed in humans, where school-age children show the heaviest infections. Strongyloides sp. was also identified, but the species identity remains uncertain. Small subunit ribosomal DNA sequences differed from published sequences of Strongyloides fuelleborni at multiple sites, but resided in a monophyletic group with other Strongyloides species with 92% bootstrap support. This may reflect a recent acquisition from a local host, or that the published sequence of S. fuelleborni is incorrect. Widespread infections with 2 nematode genera in a free-ranging baboon colony that are an important source of morbidity in human populations provide a useful model system for work on the epidemiology, control, pathology, and genetics of these parasites in a host species that is physiologically, immunologically, and genetically similar to humans.

Genetic analysis of susceptibility to infection with Ascaris lumbricoides.

Epidemiologic studies of helminthic infections have shown that susceptibility to these parasites frequently aggregates in families, suggesting the possible involvement of genetic factors. This paper presents a genetic epidemiologic analysis of Ascaris lumbricoides infection in the Jirel population of eastern Nepal. A total of 1,261 individuals belonging to a single pedigree were assessed for intensity of Ascaris infection at two time points. Following an initial assessment in which all individuals were treated with albendazole, a follow-up examination was performed one year later to evaluate reinfection patterns. Three measures of worm burden were analyzed, including eggs per gram of feces, direct worm counts, and worm biomass (weight). For all traits, variance component analysis of the familial data provided unequivocal evidence for a strong genetic component accounting for between 30% and 50% of the variation in worm burden. Shared environmental (i.e., common household) effects account for between 3% and 13% of the total phenotypic variance.

Attitudes towards helminthic infection in the Jirel population of eastern Nepal.

Intestinal worm infections, including roundworm, hookworm, and whipworm, are major international health concerns, affecting approximately one fourth of the world's population. Many intervention schemes have been attempted to control these infections in heavily exposed populations, but success has been limited because individuals are readily reinfected upon renewed exposure. Few data are available concerning people's health beliefs about soil-transmitted helminthic infections in such populations. The purpose of this study was to assess health beliefs about common helminthiasis in a population experiencing moderate to high rates of infection. The focal population for the study was the Jirel population, a tribal group distributed across nine villages in the Jiri Region of Dolakha District, eastern Nepal. The results indicate that beliefs about the types, causes, and treatments of helminthic infections have been developed and reinforced by experience and empirical evidence. People's frequent inability to confirm the efficacy of drug therapy by observing worms in stools has led to dissatisfaction with biomedical approaches. Carefully planned education programs are required to alter prevailing attitudes and improve control of soil-transmitted helminthiasis in the region.

Interactions of trans-acting factor(s) with the estradiol response element and nuclear factor 1 of the vitellogenin II gene of Japanese quail.

This study was directed at achieving an understanding of the mechanisms by which steroid hormones control the synthesis of vitellogenin (VTG) protein in the liver of the Japanese quail. Northern hybridization shows that administration of estradiol alone or with progesterone stimulates the synthesis of VTG mRNA. Gel mobility shift assay of DNA fragments containing the ERE and NF 1 shows that estradiol alone or with progesterone increases the levels of nuclear proteins that bind to these cis-acting elements of the promoter of the VTG gene. The cooperative effect of the two hormones seen at the level of expression of the VTG gene may be due to protein-protein interactions of trans-acting factors that bind to ERE and NF 1.