Laboratory of Molecular Biology and Endemic Diseases, Oswaldo Cruz Institute - Fiocruz, Rio de Janeiro, Brazil, Avenida Brasil, 4365 - Manguinhos, 21040-360.
Department of Parasitology and Microbiology, Federal University of Piauí, Teresina, Piauí, Brazil, Avenida Universitária - Ininga, 64049-550.
BMC Infect Dis. 2024 Nov 22;24(1):1335. doi: 10.1186/s12879-024-10178-6.
Piauí is located in Northeastern Brazil, an endemic area for Chagas disease, with the Brazilian semiarid representing the second region in number of people infected by the parasite Trypanosoma cruzi. The state of Piauí is one of the most socially vulnerable territories with direct impact on the access to diagnosis and treatment of Chagas disease for the population living in rural communities. Triatoma brasiliensis is the vector species of greatest epidemiological importance in Northeastern Brazil. We investigated the triatomine fauna and risk factors associated to T. cruzi transmission in two municipalities, Pedro II and Oeiras, located in different mesoregions of Piauí.
Twenty-three rural areas were selected for triatomines search and serological survey of the population. The analysis of triatomines consisted on identifying T. cruzi infection index by microscopy and kDNA-PCR followed by parasite genotyping through the use of multilocus PCR to characterize the discrete typing units (DTUS), and the identification of food sources using PCR directed to the 12S rRNA gene of vertebrates and sequencing.
A total of 1,043 triatomines identified as T. brasiliensis, Triatoma pseudomaculata, Rhodnius nasutus, Rhodnius sp. and Panstrongylus lutzi were collected. The overall positivity for T. cruzi was 4.6% and 11.4% by microscopy and kDNA-PCR, respectively. The DTUs TcV (∼ 44%) and TcI (∼ 43%) were the most prevalent in either single or mixed infections. This is the first report of TcV and TcVI infections in vectors of Piauí. The most frequent blood source was Homo sapiens (46.5%), of which ∼ 42% individuals (28/67) were collected indoors and four of them (14.3%) tested positive for T. cruzi kDNA in Pedro II. Chicken (∼ 19%), domestic cat (∼ 17%) and others were also identified as feeding sources for triatomines. Serological survey revealed 2% seroprevalence. Variables as age over 60 years (p = 0.01), Black race (p = 0.002) and occupation as retired (p = 0.004) significantly influenced the seropositivity.
Despite the reduced seroprevalence of the population, the epidemiological scenario of Chagas disease in both municipalities highlights the risk of the re-emergence of domestic vector-borne transmission. Ensuring continued entomological surveillance and vector control programs and providing access to diagnosis and treatment for the susceptible population are still needed.
皮奥伊州位于巴西东北部，是恰加斯病的流行地区，巴西半干旱地区是感染寄生虫克氏锥虫的人数第二多的地区。皮奥伊州是社会最脆弱的地区之一，这直接影响了生活在农村社区的人们对恰加斯病的诊断和治疗的获得。布氏田鼠是巴西东北部最重要的媒介种。我们调查了两个位于皮奥伊州不同中地区的佩德罗二世和奥埃拉斯市的三种原虫群和与克氏锥虫传播相关的危险因素。
选择了 23 个农村地区进行三种原虫搜索和人群的血清学调查。三种原虫的分析包括通过显微镜和 kDNA-PCR 识别克氏锥虫感染指数，随后通过使用多位点 PCR 对离散型基因分型单位 (DTUS) 进行寄生虫基因分型，并使用针对脊椎动物 12S rRNA 基因的 PCR 进行食物来源鉴定和测序。
共收集到 1043 只鉴定为布氏田鼠、伪褐带田鼠、纳氏锥虫、罗氏锥虫和隆臀粗腿按蚊的三种原虫。通过显微镜和 kDNA-PCR 检测，克氏锥虫总阳性率分别为 4.6%和 11.4%。在单一或混合感染中，最常见的 DTU 是 TcV（约 44%）和 TcI（约 43%）。这是皮奥伊州媒介中首次报告 TcV 和 TcVI 感染。最常见的血液来源是智人（46.5%），其中约 42%（28/67）个体是在室内采集的，其中 4 人（14.3%）在佩德罗二世检测到克氏锥虫 kDNA 阳性。鸡（约 19%）、家猫（约 17%）和其他动物也被鉴定为三种原虫的食物来源。血清学调查显示血清阳性率为 2%。年龄超过 60 岁（p=0.01）、黑种人（p=0.002）和退休职业（p=0.004）等变量显著影响血清阳性率。
尽管人群的血清阳性率较低，但两个城市的恰加斯病流行病学情况突显了重新出现家庭媒介传播的风险。仍需要继续进行昆虫学监测和病媒控制计划，并为易感人群提供诊断和治疗。
