American Journal of Tropical Medicine and Hygiene最新文献

Peru had one of the highest COVID-19 mortality rates globally, with the largest region, Loreto, facing unique public health challenges. This survey investigated the changes in health care access, health beliefs, and the COVID-19 behavioral responses in these communities to improve pandemic resilience. The survey was conducted as part of routine data collection from 100 adults attending Project Amazonas mobile health clinics in April 2022 in seven villages along the Ampiyacu River in Loreto. Data on demographics, health care access, public health beliefs, and societal behavioral responses to COVID-19 were analyzed and compared with previous surveys from 1999 and 2012. Fifty-four percent of the respondents reported difficulty accessing medical care, primarily due to distance. Lifetime doctor consultations increased from those recorded in 2012 and 97% of those surveyed had received two doses of the COVID-19 vaccine. The majority of participants used both traditional and modern medicine, with 47% consulting a doctor and 7% visiting a shaman for COVID-19. This survey shows high vaccine uptake and adherence to preventive measures, such as mask-wearing and social distancing, with some variation by gender. However, challenges in health care access and the use of ineffective treatments suggest there are areas to improve pandemic resilience in these communities. Local clinic expansion and training of village health promoters using new digital resources could help with this effort.

Cutaneous leishmaniasis is an endemic parasitic infection in Colombia that typically presents as ulcerated skin lesions, although atypical variants can mimic diverse dermatosis leading to misdiagnosis and delayed treatment. We report the case of a 32-year-old woman with a 15-year history of progressive granulomatous and exophytic tumor-like plaques involving her lower face and neck. She was initially misdiagnosed with lymphocutaneous sporotrichosis and treated unsuccessfully with itraconazole for 1 year. The chronic facial involvement during her formative years resulted in major aesthetic and psychosocial consequences. Histopathology and direct smear ultimately confirmed Leishmania spp. infection. She received intramuscular meglumine antimoniate with marked clinical improvement. This case illustrates the diagnostic challenges of atypical chronic cutaneous leishmaniasis and emphasizes the need for thorough evaluation in endemic regions. Early recognition and appropriate management are essential to avoid therapeutic delays and long-term psychosocial impact.

Leptospirosis is a zoonotic infection with significant mortality, yet its burden is underestimated due to diagnostic limitations. The dynamics of naturally acquired anti-Leptospira antibodies, particularly during pregnancy, remain poorly understood. This study examined the seroincidence of leptospiral infection among a cohort of pregnant women and characterized longitudinal antibody kinetics in an endemic setting. Paired sera were collected from a population-based pregnancy cohort in Anuradhapura, Sri Lanka. Women were enrolled before 12 weeks of gestation and followed up between 25-28 weeks. Data on sociodemographics, self-reported febrile illness, and hospital admissions were collected. Microscopic agglutination testing (MAT) was performed against 11 Leptospira serovars. Seroincidence was defined as seroconversion from non-reactive (<1:50) to reactive (≥1:50). Antibody kinetics were assessed using Gaussian accelerated failure time and proportional odds logistic regression models. Among 3,374 recruited women, 1,338 had paired samples. Of 1,245 seronegative at baseline, 22 (1.8%) seroconverted, yielding a seroincidence rate of 52.8/1,000 person-years (95% CI: 31.2-76.8), using the ≥1:50 definition; using a ≥1:100 cutoff, the seroincidence rate was 14.4 per 1,000 person-years (95% CI: 5.3-31.4). No significant differences in pregnancy outcomes were observed between seroconverts and non-seroconverts. Among 93 women with baseline antibody titers ≥1:50, 14 (15.1%) seroreverted to <1:50, 12 (12.9%) showed a decline in titers but remained ≥1:50, 56 (60.2%) remained unchanged, and 11 (11.8%) showed an increase in antibody titers. Antibody decay rates ranged from +0.353 to -0.789 log2 units/30 days (mean: -0.074), with faster decay at higher baseline titers. This study reveals frequent, asymptomatic Leptospira exposure and rapid antibody decline during pregnancy, highlighting substantial silent transmission and the limitations of current surveillance tools in endemic settings.

Electroencephalography (EEG) is a diagnostic and prognostic tool used worldwide in the clinical care of comatose patients. Scalability of EEG use in resource-limited settings is constrained by multiple factors, including the lack of neurophysiologist interpreters. Although machine learning offers a path to creation of automated interpretation algorithms, development is constrained by the need for independent inputs from multiple neurophysiologists. Development may be accelerated if independent inputs have high concurrence. We assessed interrater reliability of key EEG variables from studies recorded from febrile comatose African children to better understand the need for numbers of inputs required in the development of future machine learning-driven EEG interpretation algorithms. Two independent electrophysiologists interpreted 171 electroencephalograms from children in febrile coma using standard methods. Interrater reliability was highest for the presence of electrographic seizures, with overall agreement of 96.5% and kappa of 0.781 (95% CI: 0.612-0.950). Electroencephalography variables commonly used in prognostication for cerebral malaria, a common cause of febrile coma, also had high agreement rates. Electroencephalography interpretation in Malawian children with febrile coma offers high interrater reliability in key variables used to guide clinical care and estimate prognosis. This suggests that automated interpretation methods could be developed using limited numbers of human expert trainers, accelerating development of data-driven diagnostic and prognostic algorithms for resource-limited locations. Deployment of automated EEG diagnostic and prognostic interpretation algorithms for use in high-disease-burden, low-resource settings would aid in the clinical care of febrile comatose children, increasing the possibility of favorable clinical outcomes.

Plasmodium falciparum malaria remains a leading cause of mortality in Angola, with emerging antimalarial resistance threatening treatment and prevention strategies. Efficacy of artemether-lumefantrine has been reported below 90% in two provinces, underscoring the need for routine resistance surveillance. This study aimed to provide a geographically comprehensive and up-to-date overview of antimalarial drug resistance markers in Angola. Between March and July 2023, dried blood spots and demographic data were collected from P. falciparum-positive participants at 14 health facilities across 7 provinces. Multiplexed amplicon sequencing was used to characterize single nucleotide polymorphisms in 12 genes linked with resistance, estimate allele frequencies, and detect coinfecting non-falciparum Plasmodium species. Sequence data from 820 samples revealed significant geographic variation in resistance markers. In the southeast, artemisinin partial resistance markers (k13 P574L, P441L) were detected at very low prevalence (<0.1%), whereas the quintuple dhps/dhfr haplotype, linked to sulfadoxine-pyrimethamine resistance, was very prevalent (>35% of samples). In the northwest, the sextuple dhps/dhfr haplotype, a marker of higher sulfadoxine-pyrimethamine resistance, was most prevalent in the Zaire province (14.2%). The chloroquine resistance marker crt C72/V73/M74I/N75E/K76T (CVIET) haplotype had a national prevalence of 17.7%, detected in over 48% of samples from the northern sites. The mdr1 N86 genotype, linked to reduced lumefantrine susceptibility, was detected in 99.2% of samples. Coinfections of P. falciparum and non-falciparum species were rare, with no Plasmodium vivax coinfections detected. These findings highlight the need for continued monitoring to safeguard treatment efficacy, reinforcing the importance of molecular surveillance in malaria control strategies.

In February 2025, Tonga's Minister of Health declared a national dengue fever epidemic, emphasizing the urgent need to raise public awareness and implement preventative measures. In response to this declaration, a study was conducted from March to May 2025 to investigate the sociodemographic determinants affecting dengue fever awareness and preventative behaviors across Tonga's primary islands: Tongatapu, Ha'apai, and Vava'u. Researchers conducted a survey of 140 randomly selected households, achieving a 93% response rate. The results revealed that although 90% of respondents were aware of dengue fever, 67% had limited knowledge of its transmission and prevention. A multivariable analysis revealed that awareness levels were significantly higher among individuals with at least a secondary education, those who regularly listened to radio broadcasts, and those who classified dengue fever as "very serious." Focus group discussions further illuminated community misconceptions about dengue fever symptoms, which were often mistaken for those of respiratory conditions. Participants also expressed concerns about a noticeable decrease in the frequency of health officials' home visits since the onset of the coronavirus disease 2019 pandemic. Community members advocated bolstering local engagement strategies, including the utilization of community radio, village committees, and targeted networks for mothers and youth. These findings underscore the necessity for effective communication strategies, including Tongan-language radio dramas, to enhance community health resilience and encourage sustained preventative practices.

A new focus of probable artemisinin-partial resistance (ART-R) has been identified in southern Africa, driven by the P441L mutation in the Plasmodium falciparum Kelch13 gene. This emerging cross-border cluster across Angola, Namibia, and Zambia represents the fourth major ART-R focus identified in Africa, adding to the previously reported foci in East Africa and the Horn of Africa. Findings from three new studies reveal 7.3%, 33%, and 47% prevalence of P441L in specific sites in Angola, Namibia, and Zambia, respectively. The Genomics of Malaria in the Elimination 8 project enabled harmonized, real-time molecular surveillance across five countries, providing actionable data for national malaria programs. Given past failures to contain chloroquine and sulfadoxine-pyrimethamine resistance, a timely response is critical. We recommend immediate treatment policy shifts, expanded surveillance, and regional coordination to prevent the spread of ART-R. This Perspective calls on global health actors to act decisively while resistance remains geographically limited.

Diabetes mellitus (DM) is the major clinical risk factor for melioidosis, though the effect of improved glycemic control on clinical outcomes is unknown. We investigated whether glycemic control affects clinical outcomes by analyzing a composite outcome of death or intensive care unit admission among patients from the Darwin Prospective Melioidosis Study, stratified by their glycosylated hemoglobin (HbA1c). A total of 292 patients with melioidosis and DM were identified with mean HbA1c of 10.2% (95% CI: 9.8-10.4). The composite outcome occurred in 74 (24.3%) patients, but it was not associated with HbA1c when analyzed by quartiles (P = 0.48) or as a continuous variable (P = 0.41). As in other studies, bacteremia remained the strongest factor associated with adverse outcomes (odds ratio: 9.68, 95% CI: 4.15-22.58, P <0.01). Unlike in other studies, age ≥50 years trended toward protection from death/ICU (P = 0.08). These data reflect continuing gaps in understanding the complex interplay of the immune system, DM, and melioidosis.