BackgroundSleeping sickness caused by Trypanosoma brucei (T.b.) gambiense constitutes a serious health problem in sub-Sahara Africa. In some foci, alarmingly high relapse rates were observed in patients treated with melarsoprol, which used to be the first line treatment for patients in the neurological disease stage. Particularly problematic was the situation in Mbuji-Mayi, East Kasai Province in the Democratic Republic of the Congo with a 57% relapse rate compared to a 5% relapse rate in Masi-Manimba, Bandundu Province. The present study aimed at investigating the mechanisms underlying the high relapse rate in Mbuji-Mayi using an extended collection of recently isolated T.b. gambiense strains from Mbuji-Mayi and from Masi-Manimba.Methodology/Principal FindingsForty five T.b. gambiense strains were used. Forty one were isolated from patients that were cured or relapsed after melarsoprol treatment in Mbuji-Mayi. In vivo drug sensitivity tests provide evidence of reduced melarsoprol sensitivity in these strains. This reduced melarsoprol sensitivity was not attributable to mutations in TbAT1. However, in all these strains, irrespective of the patient treatment outcome, the two aquaglyceroporin (AQP) 2 and 3 genes are replaced by chimeric AQP2/3 genes that may be associated with resistance to pentamidine and melarsoprol. The 4 T.b. gambiense strains isolated in Masi-Manimba contain both wild-type AQP2 and a different chimeric AQP2/3. These findings suggest that the reduced in vivo melarsoprol sensitivity of the Mbuji-Mayi strains and the high relapse rates in that sleeping sickness focus are caused by mutations in the AQP2/AQP3 locus and not by mutations in TbAT1.Conclusions/SignificanceWe conclude that mutations in the TbAQP2/3 locus of the local T.b. gambiense strains may explain the high melarsoprol relapse rates in the Mbuji-Mayi focus but other factors must also be involved in the treatment outcome of individual patients.
A study on the issue of Human-Wildlife Conflicts (HWC) was carried out from January 1, 2018 to June 30, 2020 in the province of Kongo Central. It consisted of: (1) Identifying the causes of Human-Wildlife Conflicts in the province, (2) Determining the social impacts generated by Human-Wildlife Conflicts and (3) Identifying the prevention and mitigation measures applied to resolve the problems of Human-Wildlife Conflicts in the province. Semi-structured surveys were carried out on the basis of an interview guide among the populations of 8 territories. The sample size was 384 households per territory chosen by the simple random sampling technique. The results showed that the competition of humans and wildlife for spaces was the leading cause of Human-Wildlife Conflicts in Kongo Central province to have been cited in 41.16% of the responses of the respondents. The loss of agricultural or pastoral production cited in 27.81% of the respondents' responses would be identified as the most significant socio-economic impact that the populations would suffer. Lethal control would be the preferred measure to prevent conflict in Kongo Central province with 30.44% of citations. Finally, community awareness and compensation by the State in the event of damage would be the measures proposed in 34.93% and 23.57% respectively of the responses of the populations.
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