Geochemistry and clay mineralogy of termite mound soil and the role of geophagy in chimpanzees of the Mahale Mountains,Tanzania

Earth from a termite mound in the Mahale Mountains National Park, Tanzania, eaten by chimpanzees, was analyzed to determine the possible stimulus, or stimuli, for geophagy. The termite mound sample contains relatively high aluminum (10.0%), iron (3.0%), and sodium (0.5%). This correlates well with the mineralogy of the clay (<2 μm) fraction, which is high in metahalloysite, a 1:1 (Si:Al=1:1) clay mineral similar in chemical composition to the clay mineral kaolinite, and smectite (montmorillonite), which is a 2:1 expandable clay mineral. The combination of metahalloysite and smectite produces a substance much like the pharmaceutical Kaopectate^™ widely used by humans as an anti-diarrheal agent. These analyses and preliminary observations linking geophagy with instances of severe diarrhea, and other signs of gastrointestinal upset in the Mahale chimpanzees, suggest that one function for the ingestion of this substance by chimpanzees may be to help provide temporary relief from gastrointestinal ailments. Further detailed investigations into the relationship between health and geophagy should provide important insights into the diverse roles of this behavior as a form of self-medication.     

Infectivity, growth, development and pathology of Echinostoma caproni (Trematoda) in the golden hamster

Laboratory hamsters (Mesocricetus auratus) were experimentally infected with 75 ± 15 metacercarial cysts of Echinostoma caproni. Worms were recovered from days 7 to 89 post-infection with eight to 90 (average 37) parasites in the small intestine. Worm wet weights averaged 0.85 mg at 10 days, 1.8 mg at 17 days, 3.4 mg at 45 days, and 7.7 mg at 89 days; average dry weights for the identical days were, 0.15, 0.30, 0.70 and 2.2 mg, respectively. The average body area of worms fixed in hot (80°C) alcohol-formalin-acetic acid was 0.21 mm² on day 3, 4.9 mm² on day 10, and 17.7 mm² on day 42. Clinical signs in some hamsters included progressive unthriftiness and watery diarrhea. Gross examination revealed enlarged lymphatic nodules along the length of the small intestine. The histopathological responses of hamsters to the parasite showed erosion of the intestinal villi with lymphocytic infiltration being the primary response; hemorrhagic areas were also observed in the villi.     

Mallard ducklings (Anas platyrhynchos) experimentally infected with Echinostoma trivolvis (Digenea)

Of 8, day-old mallard ducklings, each fed 50 encysted metacercariae of Echinostoma trivolvis, 4 (50%) were infected 15-31 days postinfection (PI) with a total of 10 (2.5%) worms. The worms were attached loosely to the mucosa of the lower ileum and rectum-cloaca, and some were ovigerous by day 15 PI. Ducklings, 4-14 days old when fed encysted metacercariae, became infected with E. trivolvis adults, but ducks 150 days old were refractory to infection. Compared to our previous studies on experimental infections of echinostomes, mallard ducklings were less susceptible than golden hamsters to E. trivolvis.     

Nutrition, infant feeding and post-partum amenorrhoea in rural Bangladesh

The extent to which differences in the duration of postpartum amenorrhea among chronically malnourished women in rural Bangladesh are related to seasonal patterns of food supply, maternal nutrition, education, and patterns of infant feeding was investigated by application of multivariate hazards models with time-varying covariates. The data were derived from the Birth Interval Dynamics study in Matlab and covered close to 1800 births. Parity, education, season of birth, maternal weight, and infant supplementation all were found to affect the duration of postpartum amenorrhea among these women. Education of 5 or more years had a positive effect on the resumption of menses. Higher parity women, who were older, had longer periods of amenorrhea, as did women who gave birth in October-December. As a measure of nutritional status, the woman's weight at pregnancy termination showed a highly significant positive coefficient, indicating that improved maternal nutrition increased the likelihood of resuming menstruation. Food supplementation, which tends to decrease breastfeeding, also significantly increased the risk of resuming menstruation and had an effect independent of the other variables. When the data were analyzed by season, the most striking finding was the strong influence of education on children born during October-December (who are too young to be directly affected by the larger food supply at birth during the harvest season). The other seasons showed weaker effects of education and a stronger effect of supplementation, perhaps because these infants are older during the harvest season and thus can benefit from supplements.     

Vasopressin antagonist analogs modified at position 7

Vasopressin antagonist analogs having alanine or glycine at position 7 were essentially equipotent with analogs with proline, N-methylalanine or sarcosine at position 7. This demonstrates that the conformational constraint imposed by an N-alkyl residue at position 7 is not necessary for binding of antagonist to the receptor, the exact opposite of what is seen in agonists. This suggests that antagonists bind to the receptor in a manner which is very different from that of agonists.     

Leaf-swallowing by chimpanzees: A behavioral adaptation for the control of strongyle nematode infections

Swallowing whole leaves by chimpanzees and other African apes has been hypothesized to have an antiparasitic or medicinal function, but detailed studies demonstrating this were lacking. We correlate for the first time quantifiable measures of the health of chimpanzees with observations of leaf-swallowing in Mahale Mountains National Park, Tanzania. We obtained a total of 27 cases involving the use ofAspilia mossambicensis (63%),Lippia plicata (7%),Hibiscus sp. (15%),Trema orientalis (4%), andAneilema aequinoctiale (11%), 15 cases by direct observation of 12 individuals of the Mahale M group. At the time of use, we noted behavioral symptoms of illness in the 8 closely observed cases, and detected single or multiple parasitic infections (Strongyloides fulleborni, Trichuris trichiura, Oesophagostomum stephanostomum) in 10 of the 12 individuals. There is a significant relationship between the presence of whole leaves (range, 1–51) and worms of adultO. stephanostomum (range, 2–21) in the dung. HPLC analysis of leaf samples collected after use showed that thiarubrine A, a compound proposed to act as a potent nematocide in swallowingAspilia spp., was not present in leaves ofA. mossambicensis or the three other species analyzed. Alternative nematocidal or egg-laying inhibition activity was not evident. Worms ofO. stephanostomum were recovered live and motile from chimpanzee dung, trapped within the folded leaves and attached to leaf surfaces by trichomes, though some were moving freely within the fecal matter, suggesting that the physical properties of leaves may contribute to the expulsion of parasites. We review previous hypotheses concerning leaf-swallowing and propose an alternative hypothesis based on physical action.