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In early 2023, a substantial increase in chikungunya disease cases in South America prompted an alert from the Pan American Health Organization (1). Although most chikungunya virus (CHIKV) transmission has [...]

Little is known about the epidemiology of leptospirosis in the Dominican Republic, the second most populous country in the Caribbean. We report on findings from a multi-stage household survey across two regions in the country that reveals a previously under-estimated burden of human Leptospira infection. Our findings, based on the reference-standard microscopic agglutination test, indicate a complex picture of serogroup diversity, spatial heterogeneity in infection and risk, and a marked discrepancy between reported cases and serologically estimated infections. Given an overall seroprevalence of 11.3% (95% CI: 10.8–13.0%) and a lower estimated force of infection (0.30% per year [0.27%–0.35%]) the number of infections may exceed national reported case data by 145-fold or more. Icterohaemorrhagiae, associated with severe Weil's disease, was the most commonly identified serogroup with a serogroup-specific prevalence of 4.4%. Consistent with other settings, risk factors including age, male sex, and rat exposure were associated with higher seroprevalence. Our study highlights the need for targeted public health interventions informed by serogroup-specific dynamics, detailed spatial analyses, knowledge of local animal reservoirs, and strengthened laboratory surveillance to effectively control this pathogen. Author summary: Leptospirosis is a significant public health concern in many tropical regions, but its true burden is often unrecognized due to limited diagnostic capacity and under-reporting. Using a multistage household survey, we assessed human leptospirosis infection across two regions in the Dominican Republic. Our findings revealed a high diversity of Leptospira serogroups, regional differences in transmission, and a marked gap between reported cases and actual infections. Estimated annual infection rates were over 100 times higher than nationally reported cases, underscoring substantial under-ascertainment. We identified key risk factors for infection, including older age, male gender, and rat exposure in the home, with seroprevalence varying across regions. Notably, different Leptospira serogroups demonstrated unique transmission patterns likely linked to distinct animal reservoirs, such as rats, livestock, and dogs. For example, serogroup Australis was more common among farmers, reflecting livestock exposure. This study highlights the value of serological surveys in uncovering hidden burdens of disease and identifying tailored public health interventions, such as rodent control and animal vaccination. By understanding the complex epidemiology of Leptospira infections, our findings contribute to improved surveillance and targeted strategies to control leptospirosis in endemic settings. [ABSTRACT FROM AUTHOR]

Background Despite the World Health Organization certifying China malaria-free in 2021, the risk of local transmission caused by imported malaria cases remains a significant clinical and public health issue. It is necessary to present the changing trends of malaria in China and discuss the role of travel medicine services in consolidating malaria elimination. Methods This study systematically reviewed articles and reports related to human malaria from 2013 to 2022 published in international and Chinese databases. Data on malaria (i.e. number of cases, Plasmodium spp. diagnostic method, country of acquisition, provinces with high risk of re-introduction and transmission) were collected and synthesized, then summarized using descriptive statistics. Results Overall, 24 758 cases of malaria (>99.5% laboratory confirmed, > 99.2% imported, 0.5% fatal) were reported in China from 2013 to 2022, with a downward trend over the years (4128 cases in 2013 compared to 843 cases in 2022; χ 2 trend P  = 0.005). The last locally acquired case was reported in 2017. Plasmodium falciparum (65.5%) was the most common species identified, followed by P. vivax (20.9%) and P. ovale (10.0%). Two P. knowlesi cases were also identified in 2014 and 2017 in returned travellers from Malaysia and Indonesia, respectively. The most common countries for malaria acquisition were Ghana, Angola and Myanmar. Plasmodium vivax was mainly detected in returned travellers from Myanmar, while P. falciparum and P. ovale were detected in travellers from sub-Saharan Africa. Imported cases were mainly reported in Yunnan, Jiangsu, Sichuan, Guangxi, Shandong, Zhejiang and Henan provinces, where large numbers of Chinese people travel overseas for work. Conclusion Returned travellers from malaria-endemic countries pose a significant risk of malaria re-introduction to China. Travel medicine should be strengthened to improve the capacity and accessibility of both pre- and post-travel services, including malaria prophylaxis and prompt diagnosis of illness in returned travellers. [ABSTRACT FROM AUTHOR]

Energy production through non-conventional renewable sources allows progress towards meeting the Sustainable Development Objectives and constitutes abundant and reliable sources when combined with storage systems. From a financial viewpoint, renewable energy production projects withstand significant challenges such as competition, irreversibility of investments, high uncertainty levels, and considerable investment amounts. These facts make their financial valuation fundamental for all the agents involved. Using the Web of Science (WoS) and Scopus databases, a scientometric analysis was carried out to understand the methods that have been used in the financial appraisal of photovoltaic energy generation projects with storage systems. The present research project was developed from 268 studies published between 2013 and 2023; tools such as Bibliometrix 4.1.3, VOSViewer 1.6.19, and Tree of Science 0.0.1a9 were used. Two main findings stand out: (i) the most used methods in the literature are the traditional ones, and within them, the levelized cost of energy has been used with greater frequency; and (ii) there is an interest in analyzing the investments of these systems for residences within the framework of distributed energy generation. Two gaps were found in the literature: (i) the studies that were carried out have not comprehensively incorporated the financial challenges faced by these investments; and (ii) the evaluation of these projects has not been addressed from the perspective of a utility-based power generator. [ABSTRACT FROM AUTHOR]

Background: American Samoa successfully completed seven rounds of mass drug administration (MDA) for lymphatic filariasis (LF) from 2000–2006. The territory passed the school-based transmission assessment surveys in 2011 and 2015 but failed in 2016. One of the key challenges after the implementation of MDA is the identification of any residual hotspots of transmission. Method: Based on data collected in a 2016 community survey in persons aged ≥8 years, Bayesian geostatistical models were developed for LF antigen (Ag), and Wb123, Bm14, Bm33 antibodies (Abs) to predict spatial variation in infection markers using demographic and environmental factors (including land cover, elevation, rainfall, distance to the coastline and distance to streams). Results: In the Ag model, females had a 26.8% (95% CrI: 11.0–39.8%) lower risk of being Ag-positive than males. There was a 2.4% (95% CrI: 1.8–3.0%) increase in the odds of Ag positivity for every year of age. Also, the odds of Ag-positivity increased by 0.4% (95% CrI: 0.1–0.7%) for each 1% increase in tree cover. The models for Wb123, Bm14 and Bm33 Abs showed similar significant associations as the Ag model for sex, age and tree coverage. After accounting for the effect of covariates, the radii of the clusters were larger for Bm14 and Bm33 Abs compared to Ag and Wb123 Ab. The predictive maps showed that Ab-positivity was more widespread across the territory, while Ag-positivity was more confined to villages in the north-west of the main island. Conclusion: The findings may facilitate more specific targeting of post-MDA surveillance activities by prioritising those areas at higher risk of ongoing transmission. Author summary: The Global Programme to Eliminate Lymphatic filariasis (LF) aims to interrupt transmission by implementing mass drug administration (MDA) of antifilarial drugs in endemic areas; and to alleviate suffering of those affected through improved morbidity management and disability prevention. Significant progress has been made in the global efforts to eliminate LF. One of the main challenges faced by most LF-endemic countries that have implemented MDA is to effectively undertake post-validation surveillance to identify residual hotspots of ongoing transmission. American Samoa conducted seven rounds of MDA for LF between 2000 and 2006. Subsequently, the territory passed transmission assessment surveys in February 2011 (TAS-1) and April 2015 (TAS-2). However, the territory failed TAS-3 in September 2016, indicating resurgence. We implemented a Bayesian geostatistical analysis to predict LF prevalence estimates for American Samoa and examined the geographical distribution of the infection using sociodemographic and environmental factors. Our observations indicate that there are still areas with high prevalence of LF in the territory, particularly in the north-west of the main island of Tutuila. Bayesian geostatistical approaches have a promising role in guiding programmatic decision making by facilitating more specific targeting of post-MDA surveillance activities and prioritising those areas at higher risk of ongoing transmission. [ABSTRACT FROM AUTHOR]

Background: Understanding mortality among travellers is essential for mitigating risks and enhancing travel safety. However, limited evidence exists on severe illnesses and injuries leading to death among travellers, particularly in low- and middle-income countries and remote regions., Methods: We conducted a retrospective census study using country-level observational data from death certificates of travellers of seven South American countries (Argentina, Brazil, Chile, Colombia, Ecuador, Peru, and Uruguay) from 2017 to 2021. Causes of death were evaluated using ICD-10 codes, categorised into non-communicable diseases (NCDs), communicable diseases, and injuries. We quantified causes of death by demographic characteristics (e.g. age, sex), and geographical variables. Chi-square tests were used to assess differences between categories. We calculated crude mortality rates and incidence rate ratios (IRRs) per country's subregions., Results: A total of 17 245 deaths were reported. NCDs (55%) were the most common cause of death, followed by communicable diseases (23.4%) and injuries (18.1%). NCD-associated deaths increased after age 55 years and were highest among ≥85 years. Communicable diseases were more common at younger age (<20 years). Injury-associated deaths were more common in men (79.9%) and 25-29-year-olds (17.1%). Most deaths (68.2%) could have been avoided by prevention or treatment. Mortality risk was higher among travellers in bordering regions between countries. In Roraima [Brazil] and Norte de Santander [Colombia], locations bordering Venezuela, the death incidence rate ratio was 863 and 60, respectively. These countries' reference mortality rates in those regions were much lower. More than 80% of the deaths in these border regions of Brazil and Colombia involved Venezuelan citizens. Conclusion: The study identified risk factors and high-risk locations for deaths among travellers in seven countries of South America. Our findings underscore the need for specific health interventions tailored to traveller demographics and destination to optimise prevention of avoidable deaths in South America., (© The Author(s) 2024. Published by Oxford University Press on behalf of International Society of Travel Medicine.)