Ongoing quiescence in the Borborema Plateau Plague focus (Paraiba, Brazil)

Abstract Plague is a zoonosis caused by Yersinia pestis, whose cycle is based on a reservoir system composed of mammals and their fleas. Its transmission cycle presents long enzootic periods with undetected cases, sometimes misleading that the cycle is extinct. While surveillance activities in Brazil are being carried out only in some focal areas, the serologic results confirm the persistence of Y. pestis in all monitored areas. We studied the small mammal assembly and Y. pestis presencein the Borborema Plateau Focus within the state of Paraíba, which staged the last Brazilian plague outbreak (1986-1987), through aninventory and Y. pestis detection survey of small mammals in peridomestic and sylvatic areas from two municipalities in the state of Paraíba.The field sampling captured 45 specimens (27 marsupials, 18 rodents), of 10 species. Only two species (one marsupial, one rodent) were captured in both peridomestic and sylvatic ecotopes. The sylvatic ecotope had higher richness and abundance. No evidence of circulation of the pathogen was detected, however, this result does not discard the necessity of continuous epidemiological surveillance due to the risk of rekindling the foci after long dormant periods, especially given the current epidemiological transition occurring on a Global scale.

摘要：鼠疫是由鼠疫耶尔森菌（Yersinia pestis）引发的人畜共患病，其传播循环依赖以哺乳动物及其体表跳蚤为组分的储存宿主系统。该循环存在漫长的兽疫间歇期，期间无检出病例，有时会使学界误判该循环已绝迹。巴西目前仅在部分疫源地开展监测工作，但血清学检测结果证实，所有受监测区域均存在鼠疫耶尔森菌的持续存留。
本研究聚焦帕拉伊巴州博尔博雷马高原疫源地——该疫源地曾暴发巴西最后一次鼠疫疫情（1986-1987年）。研究通过对帕拉伊巴州两个市镇的人居周边生境与野生生境中的小型哺乳动物开展采样调查及鼠疫耶尔森菌检测，分析了该区域的小型哺乳动物群落组成与病原菌携带情况。
本次野外采样共捕获45号标本，隶属于10个物种（27只为有袋类，18只为啮齿类）。其中仅2个物种（1种有袋类、1种啮齿类）同时在人居周边与野生生境中被捕获。野生生境的物种丰富度与个体多度均更高。本次调查未检出该病原体的循环传播证据，但该结果并不排除持续开展流行病学监测的必要性：在当前全球范围内正发生流行病学转型的背景下，长期沉寂的疫源地存在再次暴发疫情的风险。