Cetron M S, Chitsulo L, Sullivan J J, Pilcher J, Wilson M, Noh J, Tsang V C, Hightower A W, Addiss D G
Division of Parasitic Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
Lancet. 1996 Nov 9;348(9037):1274-8. doi: 10.1016/S0140-6736(96)01511-5.
In 1992 two US Peace Corps volunteers (PCVs) developed central nervous system schistosomiasis due to infection with Schistosoma haematobium following recreational water exposure at Cape Maclear on Lake Malawi, an African lake considered by many to be free of schistosomiasis. To determine the transmission potential and risk for aquiring schistosomiasis in Lake Malawi, a cross-sectional survey of resident expatriates and visitors to Malawi was done during March and April, 1993.
A volunteer cohort of expatriates and visitors representing a cross-section of Malawi's foregn population answered detailed questions about freshwater contact and provided blood specimens to determine the seroprevalence of S haematobium and S mansoni by ELISA and immunoblot analyses. A survey for vector snails was conducted along Lake Malawi's southwestern shore.
The study population of 955 included 305 US citizens and 650 non-US foreign nationals. 303 of the study population had serological evidence of current or past schistosome infection. Seroprevalence was 32% (141/440) among expatriates whose freshwater exposure was limited to Lake Malawi; S haematobium antibodies were found in 135 of 141 (96%) seropositive specimens. Risk of seropositivity increased with the number of freshwater exposures at Lake Malawi resorts. Although many resort areas in the southwestern lake region posed a significant risk, Cape Maclear was the location most strongly associated with seropositivity (OR 2.9, 95% Cl 1.6-5.1). Schistosome-infected Bulinus globosus, the snail vector of S haematobium in Malawi, were found at Cape Maclear and other locations along the lakeshore.
S haematobium infection is highly prevalent among expatriates and tourists in Malawi. Recreational water contact at popular resorts on Lake Malawi is the most likely source of infection. Transmission of schistosomiasis is occurring in Lake Malawi, a previously under-recognised site of transmission.
1992年，两名美国和平队志愿者（PCV）在马拉维湖的麦克利尔角进行娱乐性水上活动后，因感染埃及血吸虫而患上中枢神经系统血吸虫病。马拉维湖是一个被许多人认为没有血吸虫病的非洲湖泊。为了确定马拉维湖血吸虫病的传播潜力和感染风险，1993年3月和4月对在马拉维的常住外籍人士和游客进行了一项横断面调查。
一组代表马拉维外国人口横断面的外籍人士和游客志愿者回答了有关淡水接触的详细问题，并提供血液样本，通过酶联免疫吸附测定（ELISA）和免疫印迹分析来确定埃及血吸虫和曼氏血吸虫的血清阳性率。在马拉维湖西南岸进行了中间宿主钉螺的调查。
研究人群共955人，包括305名美国公民和650名非美国籍外国人。研究人群中有303人有当前或过去血吸虫感染的血清学证据。在淡水接触仅限于马拉维湖的外籍人士中，血清阳性率为32%（141/440）；在141份血清阳性样本中有135份（96%）检测到埃及血吸虫抗体。血清阳性的风险随着在马拉维湖度假胜地接触淡水次数的增加而增加。虽然西南湖区的许多度假区都有很大风险，但麦克利尔角与血清阳性的关联最为密切（比值比2.9，95%可信区间1.6 - 5.1）。在麦克利尔角和湖岸其他地点发现了感染血吸虫的球拟沼螺，它是马拉维埃及血吸虫的中间宿主钉螺。
埃及血吸虫感染在马拉维的外籍人士和游客中非常普遍。在马拉维湖热门度假胜地进行娱乐性水上接触是最可能的感染源。血吸虫病正在马拉维湖传播，这是一个以前未被充分认识的传播地点。
