Cline B L, Rymzo W T, Hiatt R A, Knight W B, Berríos-Duran L A
Am J Trop Med Hyg. 1977 Jan;26(1):109-17. doi: 10.4269/ajtmh.1977.26.109.
A population-based approach was used to investigate morbidity from Schistosoma mansoni in a rural community in eastern Puerto Rico that was representative of remaining endemic foci on the island. In 1974 the prevalence of infection 855 of 1,056 inhabitants was 32.7% and the geometric mean egg output was 17.6 eggs per gram. A standardized medical history was obtained, and physical and laboratory examinations were performed on 737 (70%) of the community residents. Quantitative S. mansoni egg counts were performed on 1 gram of feces with a modified Ritchie formol-ether concentration technique; other intestinal parasites were recorded on a semi-quantitative basis. Interviews and physical examinations were conducted "blind" to minimize observer bias, and statistical analysis was done on data from 149 infected subjects and 149 noninfected controls matched by age and sex. For subjects under 20 years of age the frequency of hookworm infection and trichuriasis and absolute eosinophilia was significantly higher in the infected group, but no difference was found in the frequency of signs and symptoms of schistosomiasis. For the subjects 20 years and over, the symptom "blood in the stool" was reported more frequently in the infected group, but hematocrit level did not differ between infected and noninfected controls. Although palpable livers were noted more frequently in infected (8) than in noninfected (1) subjects 20 years and over, further evaluation of these subjects cast doubt upon a causal role for S. mansoni. These data indicate that morbidity from S. mansoni infection in the community is low, a finding consistent with the apparent decline in S. mansoni morbidity in Puerto Rico during recent decades and the relatively low intensity of infection in this community. Nevertheless, because of the sporadic occurrence of S. mansoni-induced disease on the island, and because heavily infected subjects are clearly at greater risk of disease, we are recommending treatment for community residents with high egg output.
采用基于人群的方法，对波多黎各东部一个农村社区的曼氏血吸虫病发病率进行调查，该社区是该岛其余血吸虫病流行区的代表。1974年，1056名居民中有855人感染，感染率为32.7%，每克粪便中虫卵几何平均排出量为17.6个。获取了标准化病史，并对737名（70%）社区居民进行了体格检查和实验室检查。采用改良的里氏甲醛乙醚浓缩技术对1克粪便进行曼氏血吸虫虫卵定量计数；其他肠道寄生虫采用半定量记录。访谈和体格检查在“盲态”下进行，以尽量减少观察者偏倚，并对149名感染受试者和149名按年龄和性别匹配的未感染对照的数据进行统计分析。对于20岁以下的受试者，感染组钩虫感染、鞭虫病和绝对嗜酸性粒细胞增多的频率显著更高，但血吸虫病体征和症状的频率未发现差异。对于20岁及以上的受试者，感染组报告“便血”症状的频率更高，但感染组和未感染对照组的血细胞比容水平没有差异。虽然在20岁及以上的感染（8例）受试者中比未感染（1例）受试者中更频繁地注意到可触及的肝脏，但对这些受试者的进一步评估对曼氏血吸虫的因果作用提出了质疑。这些数据表明，该社区曼氏血吸虫感染的发病率较低，这一发现与近几十年来波多黎各曼氏血吸虫发病率明显下降以及该社区相对较低的感染强度一致。然而，由于该岛曼氏血吸虫病偶有发生，且重度感染的受试者显然患病风险更大，我们建议对虫卵排出量高的社区居民进行治疗。
