Current Tropical Medicine Reports最新文献

Purpose of review: Here, we review recent progress made on the genetic characterization of Giardia duodenalis assemblages and their relationship with virulence. We also discuss the implications of virulence factors in the pathogenesis of giardiasis, and advances in the development of vaccines and drugs based on knowledge of virulence markers.

Recent findings: The use of transcriptomic and proteomic technologies as well as whole genome sequencing (WGS) from single cysts has allowed the assembly of the draft genome sequences for assemblages C and D of G. duodenalis. These findings, along with the published genomes for assemblages A, B, and E, have allowed comparative genomic investigations. In addition, the use of these methodologies for the characterization of the secretomes of trophozoite-epithelial cell interactions for assemblages A/B has led to the identification of virulence markers including energy metabolism enzymes, proteinases, high-cysteine membrane proteins (HCMPs), and variant surface proteins (VSPs). Recently, some drugs and vaccines, targeting virulence factors have been developed, offering possible alternatives to current treatment and prevention options against giardiasis.

Summary: Among the nine recognized species of Giardia, G. duodenalis stands out because of its broad spectrum of hosts and its socio-economic importance. This species comprises eight genetic assemblages (A to H), of which A and B are zoonotic, and the other assemblages have narrow host specificities. Assemblages A and B may be considered as the most virulent ones, but the existence of asymptomatic carriers and considerable genetic variability within and among these assemblages hampers the definition of common virulence factors. The attachment of Giardia trophozoites to epithelial cells and structural cytoskeleton components of the adhesive disk, such as giardins or tubulins, is proposed to play key roles, but toxins have not yet been precisely defined. However, recent transcriptomic and proteomic analyses of the secretomes of trophozoites representing assemblages A and B and interacting with particular epithelial cell lines have defined a series of virulence factors, including glycolytic (e.g., enolase) and arginolytic (e.g., arginine deiminase) enzymes, cysteine proteases (e.g., giardipain-1) and VSPs (e.g., VSP9B10A). Other factors, such as HCMPs and tenascins, have been consistently found to be excreted/secreted, but their role(s) in the pathogenesis of giardiasis has not yet been elucidated. Interestingly, recent investigations of single cysts representing assemblages C and D using advanced sequencing and informatic methods have suggested that the transcription/expression profiles of virulence factors vary both within and between assemblages, thus assemblage-specific molecules might allow adaptation to the microenvironment within the host. Importantly, some dr

Purpose of review: In this review, we report on the state of knowledge about human Q fever in Brazil and on the Guiana Shield, an Amazonian region located in northeastern South America. There is a contrast between French Guiana, where the incidence of this disease is the highest in the world, and other countries where this disease is practically non-existent.

Recent findings: Recent findings are essentially in French Guiana where a unique strain MST17 has been identified; it is probably more virulent than those usually found with a particularly marked pulmonary tropism, a mysterious animal reservoir, a geographical distribution that raises questions.

Summary: Q fever is a bacterial zoonosis due to Coxiella burnetii that has been reported worldwide. On the Guiana Shield, a region mostly covered by Amazonian forest, which encompasses the Venezuelan State of Bolivar, Guyana, Suriname, French Guiana, and the Brazilian State of Amapá, the situation is very heterogeneous. While French Guiana is the region reporting the highest incidence of this disease in the world, with a single infecting clone (MST 117) and a unique epidemiological cycle, it has hardly ever been reported in other countries in the region. This absence of cases raises many questions and is probably due to massive under-diagnosis. Studies should estimate comprehensively the true burden of this disease in the region.

Purpose of review: The aim of this review is to present a comprehensive look at five intestinal soil-transmitted helminths (STHs) of global health importance that may continue to plague low-income and rural areas of the USA and argue the need for enhanced surveillance of these infections, which primarily affect the nation's most vulnerable groups.

Recent findings: Human STH infections in middle- and high-income countries are at particular risk for being undiagnosed; as common symptoms are non-specific, differentials require a high index of clinical suspicion, and cases are concentrated in areas of poverty where access to care is limited. Although autochthonous STHs are thought to be rare in the USA, infections were once common in the American South and Appalachia and robust epidemiologic surveillance is limited post 1980s. However, recent community studies and case reports from small-scale farms and areas of high rural or inner-city poverty reveal the potential for persisting helminth infections in distinct populations of the country.

Summary: STHs are among the most common neglected tropical diseases globally causing significant morbidity in underserved communities and contributing to the continuation of cycles of poverty within vulnerable populations. Due to possible severe disease sequalae and their ability to perpetuate poverty and poverty-associated health outcomes within already vulnerable groups, it is vital that surveillance for these infections is enhanced to bolster health equity in the USA.

Purpose of review: There has been a high influx of publications on the SARS-CoV-2 and COVID-19 worldwide in the recent few months as very little was known about them. Nepal too had a substantial number of publications on the same, and there was a need to track the most relevant and impactful to the scientific community through bibliometric analysis.

Recent findings: A total of 72 publications were analyzed. Bagmati Pradesh (88%) and its district, Kathmandu (77%), was with the most publications. There were no publications from Gandaki and Karnali Province. Most of the publications were in the international medical journals (82%), 53% chose European journals to publish, and 15.27% were related to and published in psychology journals. The majority were original articles (39%) and mostly related to public health (20.83%). 59.7% of the papers had Nepalese as the first author. Most of them were affiliated with Tribhuvan University Teaching Hospital and Patan Academy of Health Sciences.

Summary: Our analysis suggests a need to shift the type of studies from observational studies to studies oriented more towards the therapeutic and clinical trials of available medicines and patient care management. Similarly, the bibliometric analysis gives an overall picture of Nepali medical research's publication status around the globe.

Purpose of review: This commentary summarizes recent literature pertaining to healthcare challenges and needs during the current pandemic among refugees and asylum seekers residing in a host country. We conducted a literature review to identify barriers to shielding these structurally marginalized populations from the impact of the COVID-19 pandemic.

Recent findings: Many populations, including refugees, migrants, and asylum seekers, endure structural vulnerabilities in refugee camps and during their resettlement. These structural vulnerabilities include fear of contacting the healthcare system, cultural differences, housing insecurity, food insecurity, discrimination, lack of health insurance, health illiteracy and lack of readily available, and culturally appropriate educational materials. During pandemics, displaced persons suffer disproportionately from poorly managed chronic diseases, economic hardships isolation, and mental illnesses, in addition to the threats posed by the infectious agent.

Summary: Underserved groups, including refugee populations, shoulder a disproportionate burden of disease during pandemics. In order to mitigate the impact of preventable chronic illnesses and also reduce the spread of COVID-19 and other easily-transmissible and deadly viruses during pandemics, governments and public health authorities need to implement policies that allow refugees, asylum seekers, and displaced persons to be fully incorporated into their respective healthcare systems, so that they can be supported and protected and to reduce the amplifying networks of transmission.

Purpose of review: The increase in international travel in recent decades has contributed to the risk of acquiring diseases considered endemic to a region or country and the change in the epidemiology of these diseases. Endemic mycoses that may be acquired by travelers in the short or long term are endemic subcutaneous mycoses such as sporotrichosis and lobomycosis, while endemic systemic mycoses are a group of serious diseases including histoplasmosis and coccidioidomycosis. Herein, we review the current knowledge and highlight the most important aspects of these fungal infections in travelers.

Recent findings: The most relevant advances in the study of these mycoses involve the epidemiological distribution; human mycoses can be fatal and there are few antifungal drugs available, increasing drug resistance, and a risk of emerging fungal diseases associated with climate change, as well as the increasing virulence, and the diagnostic strategies that may be limited in many countries.

Summary: Although endemic mycoses are relatively rare, they should be considered as potentially travel-related illnesses. A recent or late trip to an endemic country may guide the clinical suspicion, an early diagnosis, and the institution of effective therapy.