ABSTRACT
Background: Japan is estimated to host 3000 cases of Chagas disease (CD). However, there are no epidemiological data and policies for prevention and care. We aimed to analyze the current situation of CD in Japan and identify possible barriers to seeking care. Methods: This cross-sectional study included Latin American (LA) migrants living in Japan from March 2019 to October 2020. We obtained blood samples to identify participants infected with Trypanosoma cruzi, and data about sociodemographic information, CD risk factors, and barriers to access to the Japanese national health care system (JNHS). We used the observed prevalence to calculate the cost-effectiveness analysis of the screening of CD in the JNHS. Findings: The study included 428 participants, most of them were from Brazil, Bolivia and Peru. The observed prevalence was 1.6% (expected prevalence= 0.75%) and 5.3% among Bolivians. Factors associated with seropositivity were being born in Bolivia, having previously taken a CD test, witnessing the triatome bug at home, and having a relative with CD. The screening model was more cost-effective than the non-screening model from a health care perspective (ICER=200,320 JPY). Factors associated with access to JNHS were being female, length of stay in Japan, Japanese communication skills, source of information, and satisfaction about the JNHS. Interpretation: Screening of asymptomatic adults at risk of CD may be a cost-effective strategy in Japan. However, its implementation should consider the barriers that affect LA migrants in access to the JNHS. Funding: Nagasaki University and Infectious Diseases Japanese Association.
ABSTRACT
BACKGROUND: The National Program for Chagas disease was implemented in Bolivia in 2006, and it greatly decreased the number of infections through vector control. Subsequently, a treatment regimen of benznidazole (BNZ) was started in seropositive school-age children living in certified vector control areas. METHODS AND FINDINGS: We conducted a 12-month follow-up study and seven blood samples were taken during and after the treatment. Serology, conventional diagnostic PCR (cPCR) and quantitative Real-time PCR (qPCR) were performed. Plasma Th1/Th2/Th17 cytokines levels were also determined. Approximately 73 of 103 seropositive children complied with BNZ, with three interruptions due to side effects. To evaluate each individual's treatment efficacy, the cPCR and qPCR values during the final 6 months of the follow-up period were observed. Among 57 children who completed follow-up, 6 individuals (11%) showed both cPCR(+) and qPCR(+) (non reactive), 24 (42%) cPCR(-) but qPCR(+) (ambiguous) and 27 (47%) cPCR(-) and qPCR(-) (reactive). Within 14 Th1/Th2/Th17 cytokines, IL-17A showed significantly higher levels in seropositive children before the treatment compared to age-matched seronegative children and significantly decreased to the normal level one-year after. Moreover, throughout the follow-up study, IL-17A levels were positively co-related to parasite counts detected by qPCR. At the 12 months' time point, IL-17A levels of non-reactive subjects were significantly higher than either those of reactive or ambiguous subjects suggesting that IL-17A might be useful to determine the reactivity to BNZ treatment. CONCLUSIONS: Plasma levels of IL-17A might be a bio-marker for detecting persistent infection of T. cruzi and its chronic inflammation.
