American Journal of Tropical Medicine and Hygiene最新文献

Kaposi sarcoma is a low-grade vascular neoplasm linked to the human herpesvirus 8, with the AIDS-associated epidemic variant being the most common and aggressive. Although Kaposi sarcoma more commonly affects the cutaneous tissues, lymph nodes, and visceral organs, it can also be present in ocular and ocular adnexal tissues. We report a case of a 58-year-old Indo-Caribbean woman living with AIDS who presented with a large upper eyelid mass that was clinically diagnosed as Kaposi sarcoma. After the recommencement of the patient's highly active antiretroviral therapy (HAART), the lesion showed marked regression, highlighting the critical role of HAART in the management of Kaposi sarcoma. This is the first documented case of AIDS-associated ocular Kaposi sarcoma in the Eastern Caribbean region and underscores the need to consider Kaposi sarcoma as a differential diagnosis in patients living with HIV/AIDS who present with ocular or ocular adnexal masses.

Brucellosis remains an endemic disease in livestock populations in Rwanda, but the prevalence of the disease varies by geographic region. The common use of informal milk marketing channels represents a health hazard to humans when milk from Brucella-infected cows from one or more households is mixed with milk from other households for human consumption. In Rwanda, knowledge about the burden of brucellosis in livestock and factors associated with farmers' choice of milk marketing channels is very limited. The objectives of this study were 1) to estimate the seroprevalence of brucellosis in livestock in Rwamagana District in Rwanda and 2) to estimate the frequency of and identify determinants associated with farmers' choice of milk marketing channels. The seroprevalence of brucellosis in livestock at the household level was 1/160 (0.6%; 95% CI = 0.1-3.4%). Among 100 households that sold milk, 72 used informal milk trade channels. By the use of logistic regression, milk price and distance to closest milk collection center were positively associated with the use of informal milk marketing channels. Although the seroprevalence of brucellosis in livestock in Rwamagana District was low, the risk of disease transmission to humans through consumption of unpasteurized milk or milk products is not negligible. In this report, we present several policy options available to animal health authorities that can mitigate the risk of brucellosis disease transmission in populations.

Dengue infection poses a significant public health challenge in tropical countries. In Thailand, children ages 5-14 years are among the groups with the highest incidence of dengue. This study aimed to determine the prevalence of gastrointestinal (GI) manifestations in children with dengue infection and assess prognostic factors for severe dengue. We reviewed the medical records of children ages 0-14 years who were hospitalized with a diagnosis of dengue infection between 2019 and 2022 at Charoenkrung Pracharak Hospital in Bangkok, Thailand. Dengue severity was classified according to the 2009 WHO dengue guidelines. Clinical manifestations and laboratory data were analyzed for their association with severe dengue using a logistic regression model. The study included 556 dengue cases, with 48 cases (8.6%) classified as severe dengue. The mean age (SD) of patients was 9.9 (3.7) years. The most common GI symptoms were anorexia (91.7%) and vomiting (57.6%) followed by abdominal pain (38.3%), and diarrhea (33.3%). GI bleeding was found in 3.2% of patients. Hepatomegaly and ascites were found in 20.9% and 2.9% of patients, respectively. Acute liver failure and acalculous cholecystitis were found in 0.4% and 0.2% of patients, respectively. Children younger than 5 years of age exhibited a lower prevalence of vomiting and abdominal pain compared with older children, making the diagnosis of dengue more challenging. Vomiting, ascites, aspartate aminotransferase >450 U/L, and serum albumin <3.5 g/dL were significantly associated with severe dengue infection. Children with dengue infection presenting any of these factors should be closely monitored for severe dengue.

Although China has achieved malaria elimination certification, the risk of malaria transmission reintroduction due to imported malaria remains. We analyzed data on imported malaria cases collected from January 1, 2014 to December 31, 2021, using multivariable logistic regression analysis to identify the factors associated with severe and relapsing malaria. The odds of severe malaria were around 4-fold greater for patients who were initially diagnosed with a nonmalarial illness than for patients initially diagnosed with malaria. The risk of relapse from Plasmodium vivax or Plasmodium ovale varied depending on the regions of Africa where patients resided. Patients residing in western and southern Africa (compared with Central Africa) had a lower relative risk of relapse. In addition, treatment with primaquine provided protection against malaria relapse. Improving the timeliness of treatment of malaria patients could help reduce the severity of illness, and use of primaquine can mitigate the risk of relapse after treatment.

Infectious keratitis is a significant ocular disease that, if left untreated, can lead to blindness. Fungi are among the causative agents that can result in severe symptoms. Keratitis infections are prevalent globally, with a higher incidence reported in tropical and subtropical regions. The current research focused on the molecular diagnosis of fungal keratitis and its prevalence over a 3-year period in northeastern Iran. The study involved the collection of 38 corneal scraping specimens from the Eye Specialized Hospital of Khatam in Mashhad, northeastern Iran. These specimens were cultured on Sabouraud dextrose agar, and the isolates were identified using DNA-based techniques. Among the patients studied (n = 38), 22 (58%) cases were caused by Aspergillus species (A. flavus, n = 17, A. fumigatus, n = 3; A. terreus, n = 1; A. tubingensis, n = 1), seven (18%) by Neocosmospora species (N. falciformis, n = 4; N. solani, n = 3), three (7%) by Candida albicans, two (5%) by Fusarium annulatum, and one case each (2%) by Penicillium chrysogenum, Cladosporium cladosporioides, and Cytospora sp. In addition, one case had a combined infection of A. flavus and P. glabrum. The results indicate a higher incidence of fungal keratitis in males, particularly in the age range of 40-60 years. Aspergillus sp., and specifically A. flavus, had the highest prevalence. Cladosporium cladosporioides is reported for the first time in this area as causal agent of keratitis. Additionally, this is the first report of keratitis likely caused by Cytospora species.

Chikungunya virus (CHIKV), prevalent in tropical regions, is known for causing frequent outbreaks, particularly in Central Africa, South America, and Southeast Asia. It is an arbovirus transmitted by the Aedes (Ae.) aegypti and Ae. albopictus mosquitoes. Infections lead to severe joint and muscle pain, which can linger and significantly impair an individual's health, quality of life, and economic stability. Recent climatic changes and the globalization of travel have facilitated the worldwide spread of these mosquitoes. Currently, no U.S. Food and Drug Administration (FDA) approved drug is available for treating CHIKV infection. Recently, the FDA approved a live, attenuated vaccine called Ixchiq. However, this vaccine has been linked to side effects, leading the FDA to mandate additional post-marketing studies to assess the risk of severe adverse reactions similar to the virus. An emerging strategy in drug development focuses on targeting host factors that the virus exploits rather than the viral proteins themselves. This review explores the interactions between CHIKV and host factors that could be potential therapeutic targets. Despite progress in understanding the life cycle of CHIKV, the immune system's role in combating the virus still needs to be fully understood. Investigating treatments that enhance the host's immune response may offer new paths to combating CHIKV.

Diagnostic escape via Plasmodium falciparum (P. falciparum) histidine-rich protein 2 (pfhrp2) gene deletions is a major potential hurdle for global malaria elimination efforts. We investigated the prevalence of pfhrp2 gene deletions in 15 malaria-endemic villages in the state of Odisha, India, and modeled their impact on an ongoing in-country malaria intervention program. We found that 61.6% of subpatent P. falciparum infections (i.e., rapid diagnostic test [RDT]-negative and positive by polymerase chain reaction [PCR]) had pfhrp2 gene deletions, which were predominantly located in the exon 2 region (96.2%) and largely identified in samples from febrile individuals (82.6%). DNA sequencing and protein diversity features were characterized in a subset of samples from individuals with subpatent infections carrying intact pfhrp2 exon 2 loci. Our analyses revealed novel amino acid repeat motifs (231-293 amino acids), and these variant repeat sequences differed from those of RDT+/PCR+ samples. We also evaluated the state-sponsored mass screening and treatment intervention in the context of pfhrp2 gene deletions. We found that mass screening and treatment conducted alongside additional interventions (e.g., long-lasting insecticidal net distribution, indoor residual spraying) reduced the relative risk of infection for both P. falciparum parasites harboring a pfhrp2 deletion (adjusted relative risk ratio [aRRR] = 0.3; 95% CI = 0.1-1.0) and P. falciparum parasites with intact pfhrp2 genes (aRRR = 0.4; 95% CI = 0.2-1.1) when compared with the use of mass screening and treatment by RDT alone. Combined, our findings highlight the need for alternative diagnostic targets and tools as India moves toward its goal of malaria elimination by 2030.

In Colombia, human leishmaniasis is endemic in rural areas, with increasing reports of outbreaks and cases in urban areas. Cartagena, an urban city in the Colombian Caribbean with a wildland-urban interface, faced its first local cases between 2011 and 2015. Despite reports, visceral leishmaniasis (VL) remains neglected and understudied and almost devoid of active surveillance. Here we report the epidemiological and molecular surveillance of Leishmania species in humans, domestic dogs, and sandflies at the wildland interface in two poverty-stricken neighborhoods of Cartagena. In October 2021, we conducted a surveillance study in the El Toril and La Quinta neighborhoods. Blood samples were collected from 150 healthy humans and 77 domestic dogs for Leishmania species testing by using molecular tools. Five human samples (3.3%) tested positive for Leishmania, one case in El Toril and four cases in La Quinta. The Leishmania donovani complex was detected in three human samples, and all dog samples tested negative for Leishmania. CDC light traps placed for three consecutive days in peridomiciliary areas of the Leishmania-positive case in El Toril allowed the capture of seven females of Lutzomyia dubitans, but none tested positive for Leishmania. Multiple attempts to conduct entomological surveillance in La Quinta were unsuccessful because of non-study-related issues. Our findings contribute to the characterization of the epidemiology of VL in Cartagena, revealing possible neglected cryptic infections in two neighborhoods with an urban-wildland interface.

Artificial blood feeding of mosquitoes is essential for their rearing in insectaries as well as for mosquito-borne pathogen transmission experiments. We conducted a systematic review and meta-analysis of the different artificial feeding systems available for mosquitoes to synthesize evidence regarding their efficacy in terms of feeding rates and fecundity. PubMed, Scopus, Web of Science, and Google Scholar were systematically searched to retrieve 1,822 experimental studies assessing the efficacy of artificial feeding systems. After assessing eligibility and risk of bias, 25 studies were included in the final analysis. Studies were reviewed and meta-analysis was conducted using random-effects model. The primary outcomes were feeding rates and fecundity of mosquitoes belonging to genera Aedes, Culex, and Anopheles for the different systems. Subgroup analyses with respect to membrane, blood source, and mosquito genera were conducted. Sensitivity analysis was done to assess heterogeneity. The overall pooled estimate of feeding rate of mosquitoes and the average number of eggs laid per female mosquito using artificial blood-feeding systems were 72% (66-77%) and 71.9 (56.68-87.12), respectively. Results from this systematic review are suggestive of the advantages of novel techniques, such as Digital Thermo Mosquito Blood Feeder and 3D-printed feeders. The study provides evidence for improved feeding rates of mosquitoes in systems using bovine blood and synthetic membranes such as latex.

Zika virus (ZIKV) outbreaks occur sporadically in tropical and subtropical regions. At present, there are no licensed vaccines or specific treatments available for ZIKV. Ivermectin is approved for use in humans as an antiparasitic drug. In this study, we conducted in vitro cell culture and in vivo experiments in rhesus macaque hosts and Aedes aegypti vectors to investigate the potential of ivermectin as an inhibitor of ZIKV infection. In LLC-MK2 mammalian cells, ivermectin inhibited ZIKV growth in vitro with 50% inhibitory concentration (IC50) values in the ranges of 7.4-21.3 µM and 4.0-11.6 µM for African and Asian genotypes, respectively. In C6/36 mosquito cells, ivermectin inhibited ZIKV growth in vitro with IC50 values in the ranges of 10.1-17.4 µM and 8.0-15.6 µM for the African and Asian genotypes, respectively. Despite these in vitro results, high-dose ivermectin prophylaxis (1.2 mg/kg for 3 consecutive days) failed to prevent ZIKV infection in rhesus macaque and did not alter ZIKV IgM antibody production. The secondary transfer of ivermectin from nonhuman primate blood to mosquito vectors at 3 days post-ZIKV inoculation and after the last dose of ivermectin administration showed no reduction in ZIKV replication in mosquitoes. However, mosquito survival rates were significantly (P <0.0001) lower after exposure to ivermectin, thereby potentially impacting ZIKV transmission through increased vector mortality. However, further investigation is needed to determine dosing regimens that may realize these effects in vivo.