Krumkamp Ralf, Aldrich Cassandra, Maiga-Ascofare Oumou, Mbwana Joyce, Rakotozandrindrainy Njari, Borrmann Steffen, Caccio Simone M, Rakotozandrindrainy Raphael, Adegnika Ayola Akim, Lusingu John P A, Amuasi John, May Jürgen, Eibach Daniel
Department of Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
German Center for Infection Research, Hamburg-Lübeck-Borstel-Riems, Germany.
Clin Infect Dis. 2021 Apr 26;72(8):1358-1366. doi: 10.1093/cid/ciaa223.
Cryptosporidiosis has been identified as one of the major causes of diarrhea and diarrhea-associated deaths in young children in sub-Saharan Africa. This study traces back Cryptosporidium-positive children to their human and animal contacts to identify transmission networks.
Stool samples were collected from children < 5 years of age with diarrhea in Gabon, Ghana, Madagascar, and Tanzania. Cryptosporidium-positive and -negative initial cases (ICs) were followed to the community, where stool samples from households, neighbors, and animal contacts were obtained. Samples were screened for Cryptosporidium species by immunochromatographic tests and by sequencing the 18S ribosomal RNA gene and further subtyped at the 60 kDa glycoprotein gene (gp60). Transmission clusters were identified and risk ratios (RRs) calculated.
Among 1363 pediatric ICs, 184 (13%) were diagnosed with Cryptosporidium species. One hundred eight contact networks were sampled from Cryptosporidium-positive and 68 from negative ICs. Identical gp60 subtypes were detected among 2 or more contacts in 39 (36%) of the networks from positive ICs and in 1 contact (1%) from negative ICs. In comparison to Cryptosporidium-negative ICs, positive ICs had an increased risk of having Cryptosporidium-positive household members (RR, 3.6 [95% confidence interval {CI}, 1.7-7.5]) or positive neighboring children (RR, 2.9 [95% CI, 1.6-5.1]), but no increased risk of having positive animals (RR, 1.2 [95% CI, .8-1.9]) in their contact network.
Cryptosporidiosis in rural sub-Saharan Africa is characterized by infection clusters among human contacts, to which zoonotic transmission appears to contribute only marginally.
隐孢子虫病已被确认为撒哈拉以南非洲幼儿腹泻及腹泻相关死亡的主要原因之一。本研究对隐孢子虫阳性儿童的人际和动物接触者进行追踪，以确定传播网络。
在加蓬、加纳、马达加斯加和坦桑尼亚，收集5岁以下腹泻儿童的粪便样本。对隐孢子虫阳性和阴性的初始病例（IC）进行社区追踪，采集其家庭、邻居及动物接触者的粪便样本。通过免疫层析试验、18S核糖体RNA基因测序对样本进行隐孢子虫种类筛查，并进一步对60 kDa糖蛋白基因（gp60）进行亚型分析。确定传播集群并计算风险比（RR）。
在1363例儿科初始病例中，184例（13%）被诊断为隐孢子虫感染。从隐孢子虫阳性IC中抽取了108个接触网络，从阴性IC中抽取了68个。在阳性IC的39个（36%）网络中的2个或更多接触者中检测到相同的gp60亚型，而在阴性IC的1个（1%）接触者中检测到相同亚型。与隐孢子虫阴性IC相比，阳性IC的家庭成员为隐孢子虫阳性（RR，3.6 [95%置信区间{CI}，1.7 - 7.5]）或邻居儿童为阳性（RR，2.9 [95% CI，1.6 - 5.1]）的风险增加，但接触网络中的动物为阳性的风险未增加（RR，1.2 [95% CI，0.8 - 1.9]）。
撒哈拉以南非洲农村地区的隐孢子虫病以人际接触中的感染集群为特征，人畜共患病传播似乎仅起很小的作用。
