The incidence of human brucellosis is not documented in Rwanda despite several reports on the disease in cattle. Because brucellosis has been associated with abortion, the aim of this study was to investigate the prevalence of positive serology in women presenting with abortion and/or stillbirth. The study was done in Huye District, in the Southern Province of Rwanda, and the patients were recruited from both the University Teaching Hospital of Butare (CHUB) and Kabutare District Hospital. Serum samples were collected and the Rose Bengal plate test (RBPT) was performed on each sample. A questionnaire was also used to investigate potential contacts with animals and/or consumption of raw milk. A total of 60 women were recruited and 15 (i.e., 25%) were Brucella seropositive. The questionnaire showed that those with seropositivity either were in contact with domestic animals (cattle, goat, or sheep) or were consuming raw cow's milk. Human brucellosis appears to be of public health importance in Rwanda and more attention should be drawn on the disease. The current study provides a basis for larger studies to establish the incidence of human brucellosis in Rwanda. More mechanistic studies will also demonstrate the pathogenicity of Brucella in human placentas.

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A rumen fistulated wether was used for continuous infusion of a 2-bromoethanesulfonic acid (BES) solution (2 g/d in 50 ml of water). The infusion was started after introduction of a pulse dose of BES (2 g) into the rumen. Immediately after introduction of the pulse dose, methane concentration in rumen gases was lowered from about 40 to less than 1%, with concomittant decreases and increases in the molar proportions of acetic and propionic acids respectively in the rumen volatile fatty acids. After 4 days of infusion however, and despite repeated pulse dosage of BES, methanogenesis adapted to BES and methane concentration in rumen gases reached 20%. Addition of BES to incubations of rumen contents with hay resulted in considerable inhibition of methanogenesis. Extra addition of methanol in such incubations increased both acetate and methane production, whereas addition of formate had no effect. In a second experiment using a second rumen fistulated whether, a 4 day control period was followed by 10 days of daily introduction of 11 of cattle cecal contents into the rumen. The cattle cecal contents were collected from slaughterhouse cattle, filtered and kept at -20 degrees C until use. Comparison of in vitro fermentation of thawed with fresh contents showed absence of methanogenesis but not of reductive acetogenesis after freezing and thawing. Evidence for the latter was sought by calculation of metabolic hydrogen recoveries from amounts of end products formed in incubations. In a similar way, evidence for induction of reductive acetogenesis was sought from incubations in vitro, carried out with rumen contents obtained before, during and after introduction of cecal contents into the rumen. No such evidence was obtained.

The caecal fermentation pattern was studied in four litters of rabbits. Rabbits were sequentially slaughtered at the age of 4 (before weaning), 6, 8 and 11 weeks. Their caecal contents were analyzed and incubated in vitro at 39 degrees C for 6 and 12 h. Net productions of short-chain fatty acids (SCFA), hydrogen and methane were determined. The average caecal weight increased three-times within two weeks after weaning, from 31.4 to 93.7 g. At the end of the experiment, the caecal weight was on average 134.4 g. A large variability of the SCFA concentration observed before weaning decreased after weaning. Measurements of caecal metabolite profiles and results of in vitro experiments indicated a certain decrease of propionate in favour of butyrate, associated with the weaning. The establishment of methanogens in rabbits was slow. Methanogenesis started in one out of four rabbits at the age of 6 weeks. Five weeks later, one of four rabbits still did not produce methane. The hydrogen recovery decreased between the 4th and the 6th week of age, due to the increase of the butyrate/propionate ratio. After the 6th week, the hydrogen recovery increased with age, apparently because of the increase in methane production. Hydrogen recovery tended to increase during incubation, suggesting a decrease of reductive acetogenesis. This increase was observed both in methanogenic and non-methanogenic rabbit caecal cultures. In former cultures, the ratio CH4/SCFA rose with time of incubation.

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