American Journal of Tropical Medicine and Hygiene最新文献

Neurocysticercosis (NCC) is the most common helminthic infection of the human central nervous system (CNS), and a major cause of acquired epilepsy in most of the world. Although outcomes of NCC have been improved by advanced diagnostic tests, antiparasitic drugs, and appropriate anti-inflammatory treatment, little attention has been paid to calcified NCC. Calcification is a common outcome in NCC and carries increased risk for seizures and hippocampal atrophy/sclerosis. The pathophysiological mechanisms leading to calcification instead of complete resolution are basically unknown. Understanding the causes and mechanisms of calcification can lead to improved therapies aimed at reducing the likelihood of residual calcification or the underlying pathological mechanisms, after the resolution of parasitic lesions in the human CNS.

Despite extensive vector control programs, dengue remains a significant global health challenge, with outbreaks rising worldwide. Effective dengue control requires reinforcing the surveillance systems and using surveillance data to gain a better understanding of dengue dynamics at both spatial and temporal scales. We studied the effect of socioeconomic and land cover on the presence of dengue hotspots in Medellin (Colombia) from 2010 to 2020 and identified recurrent hotspots during severe epidemic (SE), epidemic (E), and non-epidemic (NE) years. We focused on spatial autocorrelation using global and local indicators of spatial association over 40,814 georeferenced dengue cases. Later, we tested if the spatial units identified as hotspots, recurrent hotspots, and non-hotspots were evenly distributed among socioeconomic strata and land cover categories. During the study period, 50% of the dengue cases were concentrated in 26% of the study area. We identified statistically significant hotspots, some recurring for up to 7 years with their spatial patterns differing between SE, E, and NE years, even though some recurred over time. Recurrent hotspots predominantly occurred in low-medium socioeconomic strata and were absent in the highest strata. Also, they predominated in human-made structures. The interaction between socioeconomic factors, land cover, and potentially, the vector presence seems to explain the spatial variation of dengue epidemics and their recurrent hotspots in Medellin.

Post-kala-azar dermal leishmaniasis (PKDL) is a neglected tropical disease that can develop after treatment of leishmaniasis. It causes significant health risks and serves as a reservoir, perpetuating transmission. Current information on PKDL characteristics is crucial for effective disease management and control. This study aimed to describe clinical and epidemiological characteristics of PKDL patients in eastern Sudan. A retrospective cross-sectional study was conducted on suspected PKDL patients (N = 37) at a tertiary hospital in eastern Sudan. Blood samples were tested for anti-rK39 antibodies to confirm the diagnosis of the disease. Demographic, clinical, and epidemiological data of the PKDL patients were gathered and analyzed. Most PKDL cases (69.4%) came from specific locations involving one ethnic group (94.6%), mainly affecting young males (54.1%). A family history of PKDL was noted in only 27.0% of cases; 51.4% developed PKDL within 1 month after visceral leishmaniasis (VL) treatment. Most cases (56.8%) were grade 1 (a low level of parasitic load), predominantly featuring macular (51.4%), papular (18.9%), and nodular (13.5%) lesions. All patients had skin rashes; 91.9% exhibited no fever, and 29.7% reported itching. Lesions appeared within a month after VL treatment, with most patients recovering spontaneously within 3-18 months. PKDL was particularly prevalent in specific regions and ethnic groups, namely the Masaleet and Dago tribes. These findings can enhance PKDL understanding and management in the region.

Male mosquitoes containing the endosymbiont Wolbachia (Wb+) can be used as a tool to suppress wild mosquito populations through a technique termed incompatible insect technique (IIT). IIT programs reduce wild mosquitoes via incompatible matings between released males and wild females to reduce the number of viable offspring produced in the next generation. Successful programs rely on regular release of incompatible males to outcompete wild males for female mates. Past IIT programs have relied on local production of Wb+ males to support regular releases of incompatible males. Here, we evaluated the survival and dispersal of packed and shipped Wb+ Aedes aegypti males in mark-release-recapture studies at a release site in the British Virgin Islands (BVI), separated by over 3,600 miles from the centralized production facility. Released mosquitoes were recaptured using BG-Sentinel 2 traps collected daily for up to 7 days after release. Wb+ male mosquitoes packed and shipped from a centralized production facility performed similarly to males that were locally reared in the BVI in survival, dispersal, and recapture rates. Our results support the conclusion that packing and shipping live Wb+ male mosquitoes does not impact their ability to survive and disperse in release sites and suggests that IIT mosquito control programs can feasibly be conducted nearly anywhere in the world without the need for local mosquito production facilities.

Dengue virus produces dengue fever, which can cause severe manifestations. Virus serotype and genotype may impact the epidemiology and severity of the disease. At the Hospital México (Costa Rica), dengue diagnosis and serotyping are performed with molecular tests, but selected samples are sequenced using Illumina technology. In May 2024, we analyzed two dengue-positive samples through genomic sequencing and detected dengue serotype 2, Cosmopolitan genotype. Phylogenetic comparisons revealed that the Costa Rican genomes are closely related to those from Brazil, Peru, and Colombia. Molecular dating estimated that the sequences from Costa Rica diverged in January 2024, suggesting that this genotype may already have been circulating in the country. The emergence of this genotype could impact the severity and epidemiology of dengue in Costa Rica. Therefore, genomic and epidemiological surveillance of dengue cases locally is important to better understand the public health impact of this new genotype in the country.

Hepatitis A virus (HAV) is an RNA virus that causes acute hepatitis and is transmitted via the fecal-oral route. It has historically been highly endemic in Thailand, where most children develop lifelong immunity after infection. Economic development and improved sanitation have reduced HAV transmission, but immunity levels have declined, raising concerns about potential future outbreaks. This study aims to assess the seroprevalence of HAV antibodies in Thailand in 2024, 10 years after the last national survey in 2014, and to evaluate current immunity levels to inform public health strategies. A cross-sectional study was conducted in a population aged 6 months to 80 years across Thailand's geographic regions. A total of 4,312 serum samples were tested for anti-HAV antibodies using the chemiluminescent microparticle immunoassay. The seroprevalence data were compared with findings from previous surveys in 2004 and 2014. The study showed a significant decline in population immunity to HAV, with the age at which 50% of individuals had antibodies increasing from 36 in 2004 to 42 in 2014, and to 47 years in 2024. A majority of the population remained susceptible to HAV, particularly among younger age groups. Thailand has transitioned to low HAV endemicity, with a large proportion of the population lacking immunity. Despite the absence of significant outbreaks in recent decades, the risk of future outbreaks remains, particularly from imported cases. Enhanced surveillance and vaccination strategies are necessary to prevent future HAV transmission and manage public health risks.