In order to better understand the epidemiology of Human and Animal trypanosomiasis that occur together in sleeping sickness foci, a study of prevalences of animal parasites (Trypanosoma vivax, T. congolense “forest type”, and T. simiae) infections was conducted on domestic animals to complete the previous work carried on T. brucei gambiense prevalence using the same animal sample. 875 domestic animals, including 307 pigs, 264 goats, 267 sheep and 37 dogs were sampled in the sleeping sickness foci of Bipindi, Campo, Doumé and Fontem in Cameroon. The polymerase chain reaction (PCR) based method was used to identify these trypanosome species. A total of 237 (27.08%) domestic animals were infected by at least one trypanosome species. The prevalence of T. vivax, T. congolense “forest type” and T. simiae were 20.91%, 11.42% and 0.34% respectively. The prevalences of T. vivax and T. congolense “forest type” differed significantly between the animal species and between the foci (p < 0.0001); however, these two trypanosomes were found in all animal species as well as in all the foci subjected to the study. The high prevalences of T. vivax and T. congolense “forest type” in Bipindi and Fontem-Center indicate their intense transmission in these foci.

A hstractAn outburst of lethal gas from Lake Nyos, Cameroon, killed more than 1,700 people on 2 1 August 1986. The surveys carried out so far indicate that a considerable portion of the CO, dissolved in the lake was released to the atmosphere and asphyxiated the people. We revisited the lake in December 1988. The conductivity-temperature-depth profiler (CTD) measurements and chemical analysis of the lake water revealed that temperature, total dissolved solids (TDS), and CO, content of the bottom water increased in parallel fashion, especially in the bottom layer, during the preceding 25 months. The result supports the view thdt CO1 is being supplied to the lake bottom in the form of warm, CO,-charged, mineralized water. From the increments of temperature and CO, during the period, fluxes of heat and CO, were estimated to be 0.43 MW and 1 .O Mmol yr I. The CO1 flux is large enough to saturate the lake's hypolimnion within -30 yr. In the 1988 survey, the very bottom layer of the lake was estimated to be close to saturation with CO,. Using the CO,-TDS-Si relationship and temperature dependence of the solubility of amorphous silica, we estimated the chemical composition of the warm, mineralized water; these estimates suggest the existence of a CO,-saturated fluid below the sedimentary cover.

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Microbiological water quality of the Mfoundi River watershed at Yaoundé, Cameroon, as inferred from indicator bacteria of fecal contamination Djuikom, E.; Njine, T.; Nola, M.; Sikati, V.; Jugnia, L.-B. Abstract. Using the membrane filtration technique to count total coliform (TC), fecal coliform (FC) and fecal streptococci (FS), the microbiological water quality of the Mfoundi River and four of its representative tributaries at Yaoundé, Cameroon, was assessed for human use and contact. Sampling was conducted so as to examine the potential origin of fecal contamination and how rainfall affects the measured concentrations of indicators organisms. Our results revealed that waters were not safe for human use or primary contact according to the standards for water quality established by the Word Health Organization (WHO). Indeed, these waters exhibited high concentrations of TC (Mean ± SD = 5.6 × 10 8 ± 2.5 × 10 6 CFU/100 ml), FC (Mean ± SD = 6.8 × 10 5 ± 2.4 × 10 3 CFU/100 ml) and FS (Mean ± SD = 7.3 × 10 5 ± 2.1 × 10 3 CFU/100 ml) that varied with the sampling sites and points. FC/FS ratio suggested that this contamination was more from warm-blooded animals than humans and correlation analysis points to the role of rainfall as a contributing factor, which enhanced the bacterial numbers detected. We conclude that there is a great potential risk of infection for users of waters from the Mfoundi River and its tributaries at Yaoundé.

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