Long term study on the effect of mollusciciding with niclosamide in streamhabitats on the transmission of schistosomiasis mansoni after community-basedchemotherapy in Makueni District, Kenya

Background: Schistosoma mansoni infection is a persistent public health problem in many Kenyan communities. Although praziquantel is available, re-infection after chemotherapy treatment is inevitable, especially among children. Chemotherapy followed by intermittent mollusciciding of habitats of Biomphalaria pfeifferi, the intermediate host snail, may have longer term benefits, especially if timed to coincide with natural fluctuations in snail populations. Methods: In this cohort study, the Kambu River (Intervention area) was molluscicided intermittently for 4 years, after mass chemotherapy with praziquantel in the adjacent community of Darajani in January 1997. The nearby Thange River was selected as a control (Non-intervention area), and its adjacent community of Ulilinzi was treated with praziquantel in December 1996. Snail numbers were recorded monthly at 9–10 sites along each river, while rainfall data were collected monthly, and annual parasitological surveys were undertaken in each village. The mollusciciding protocol was adapted to local conditions, and simplified to improve prospects for widespread application. Results: After the initial reduction in prevalence attributable to chemotherapy, there was a gradual increase in the prevalence and intensity of infection in the non-intervention area, and significantly lower levels of re-infection amongst inhabitants of the intervention area. Incidence ratio between areas adjusted for age and gender at the first follow-up survey, 5 weeks after treatment in the non-intervention area and 4 months after treatment in the intervention area was not significant (few people turned positive), while during the following 4 annual surveys these ratios were 0.58 (0.39-0.85), 0.33 (0.18-0.60), 0.14 (0.09-0.21) and 0.45 (0.26-0.75), respectively. Snail numbers were consistently low in the intervention area as a result of the mollusciciding. Following termination of the mollusciciding at the end of 2000, snail populations and infections in snails increased again in the intervention area. Conclusion: The results of this study demonstrate that in the Kenyan setting a combination of chemotherapy followed by intermittent mollusciciding can have longer term benefits than chemotherapy alone

Development of a TB vaccine trial site in Africa and lessons from the Ebola experience

Tuberculosis is the deadliest infection of our time. In contrast, about 11,000 people died of Ebola between 2014 and 2016. Despite this manifest difference in mortality, there is now a vaccine licensed in the United States and by the European Medicines Agency, with up to 100% efficacy against Ebola. The developments that led to the trialing of the Ebola vaccine were historic and unprecedented. The single licensed TB vaccine (BCG) has limited efficacy. There is a dire need for a more efficacious TB vaccine. To deploy such vaccines, trials are needed in sites that combine high disease incidence and research infrastructure. We describe our twelve-year experience building a TB vaccine trial site in contrast to the process in the recent Ebola outbreak. There are additional differences. Relative to the Ebola pipeline, TB vaccines have fewer trials and a paucity of government and industry led trials. While pathogens have varying levels of difficulty in the development of new vaccine candidates, there yet appears to be greater interest in funding and coordinating Ebola interventions. TB is a global threat that requires similar concerted effort for elimination

ケニアの海岸地方における住血吸虫症の疫学的研究 パイロット地区住民の寄生虫学的所見

ビルハルツ住血吸虫症の横断的疫学調査をケニアの海岸地方のある村で行った。登録された1,206名の住民の内853名の尿を検査した結果，全体としての虫卵陽性率は68.2%，平均虫卵排泄数は50.0/hourであった。人口動態的，地理的にその内容を分析すると，次のような結果を得た。年齢別に，男女を比較すると，虫卵陽性率，平均虫卵排泄数，重症感染者率，血尿陽性率共に特に若年成人で女性が男性よりも高い値を示した。これは水との接触行動の違いによるものと推量される。本流と支流に沿って住む者の間では，支流の者の虫卵陽性率，平均虫卵排泄数が高かった。これは川の汚染の程度が水系によって異なるためであろう。三主要部族間に虫卵陽性率，平均虫卵排池数の差は認められなかった。A cross-sectional epidemiological survey on Schistosoma haematobium infection was carried out in a small community in the coastal area of Kenya. From the 1,206 registered inhabitants, 853 urine specimens were examined. The overall prevalence and intensity of infection were 68.2 percent and 50.0/hour respectively. Some demographical and geographical differences of infection were analyzed. The profile of age-related distribution showed sexual differences in the prevalence and intensity of infection, the prevalence of heavy infection (>1,OOO/hour) and the prevalence of gross hematuria. Those of females are higher than those of males especially after adolescence. This is probably due to the difference in water contact behavior. The marked higher prevalence and intensity of infection were observed among people who lived along the branch of a main river than those who lived along the main river. The difference might be due to the different degree of contamination in the rivers. There was no difference in prevalence and intensity of infection among the three main tribes