The incidence of Orientia tsutsugamushi infection in rural South India.
The incidence of Orientia tsutsugamushi infection in rural South India.
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DOI：
10.1017/s0950268822001170
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发表时间：
2022-06-29
影响因子：
4.2
通讯作者：
Schmidt, Wolf-Peter
中科院分区：
文献类型：
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作者：
Devamani, Carol S.;Prakash, John A. J.;Alexander, Neal;Stenos, John;Schmidt, Wolf-Peter
恙虫病是一种在亚洲由恙虫病东方体引起的常见细菌感染。这项血清学队列研究估计了印度南部农村人口感染的发生率。参与者在基线时通过系统抽样在46个村庄登记，并于次年重新访问。采用ELISA法检测血样中IgG抗体，然后对ELISA阳性的血样进行间接免疫荧光测定（IFA）。两个时间点之间的血清转化（ELISA）或至少4倍滴度升高（IFA）被定义为病例。除了粗略的发病率估计外，我们还使用了跨日历月的分段线性率，其比率与当地医院病例的月发病率成正比，以解决季节性和随访时间不等的问题。在402名参与者中，61.7%是女性。平均年龄46.7岁（13 ~ 88岁）。21名参与者有血清学感染的迹象。估计发病率为每100人年4.4例（95% CI 2.8-6.7）。分段线性率方法的估计结果相似，为4.6 / 100人年（95% CI 2.9-6.9）。考虑到先前对同一研究人群中有症状的恙虫病发病率的估计，只有约2-5%的感染可能导致临床相关疾病。
Scrub typhus is a common bacterial infection in Asia caused by Orientia tsutsugamushi. This serological cohort study estimated the incidence of infection in a rural population in South India. Participants were enrolled through systematic sampling in 46 villages at baseline, and revisited the following year. Blood samples were tested for IgG antibodies using ELISA, followed by indirect immunofluorescence assays (IFA) in those positive for ELISA at both rounds. A case was defined as sero-conversion (ELISA), or at least a 4-fold titre increase (IFA), between the two time points. In addition to crude incidence rate estimates, we used piecewise linear rates across calendar months, with rates proportional to the monthly incidence of local hospital cases to address seasonality and unequal follow-up times. Of 402 participants, 61.7% were female. The mean age was 46.7 years, (range 13–88). 21 participants showed evidence for serological infection. The estimated incidence was 4.4 per 100 person-years (95% CI 2.8–6.7). The piecewise linear rates approach resulted in a similar estimate of 4.6 per 100 person years (95% CI 2.9–6.9). Considering previous estimates of symptomatic scrub typhus incidence in the same study population, only about 2–5% of infections may result in clinically relevant disease.