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As countries move toward malaria elimination, imported infections become increasingly significant as they often represent the majority of cases, can sustain transmission, cause resurgences, and lead to mortality. Here we review and critique current methods to prevent malaria importation in countries pursuing elimination and explore methods applied in other transmission settings and to other diseases that could be transferred to support malaria elimination. To improve intervention targeting we need a better understanding of the characteristics of populations importing infections and their patterns of migration, improved methods to reliably classify infections as imported or acquired locally, and ensure early and accurate diagnosis. The potential for onward transmission in the most receptive and vulnerable locations can be predicted through high-resolution risk mapping that can help malaria elimination or prevention of reintroduction programs target resources. Cross border and regional initiatives can be highly effective when based on an understanding of human and parasite movement. Ultimately, determining the optimal combinations of approaches to address malaria importation will require an evaluation of their impact, cost effectiveness, and operational feasibility.
Malaria has been the greatest scourge of humankind for many millennia, and as a consequence has had more impact than any other pathogen in shaping the human genome. The sequencing of the human genome provides a new opportunity to determine the genetic traits that confer resistance to infection or disease. The identification of these traits can reveal immune responses, or host–parasite interactions, which may be useful for designing vaccines or new drugs. Similarly, the parasite genome sequence is being exploited to accelerate the development of new antimalarial interventions, for example by identifying parasite metabolic pathways that may be targeted by drugs. The malaria parasites are well known for their ability to undergo antigenic variation, and in parallel to cause a diverse array of disease syndromes, including the severe syndromes that commonly cause death. Genome-based technologies are being harnessed to relate gene and protein expression levels, or genetic variation, to the parasite forms that are targets of protective immunity. Well-conducted clinical studies are required to relate host or parasite diversity with disease. However, genomics studies of human populations raise important ethical issues, such as the disposition of data related to disease susceptibility or paternity, and the ability of communities to understand the nature of the research.
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Urinary Infections
By Clifford Morson, pages 1–76. John Dale Sons and Danielson Ltd., 83–91. Great Titchfield St., W. I., London, 1933
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ABSTRACT.
Epidemiology, ventilator management, and outcomes in patients with acute respiratory distress syndrome (ARDS) because of coronavirus disease 2019 (COVID-19) have been described extensively but have never been compared between countries. We performed an individual patient data analysis of four observational studies to compare epidemiology, ventilator management, and outcomes. We used propensity score weighting to control for confounding factors. The analysis included 6,702 patients: 1,500 from Argentina, 844 from Brazil, 975 from the Netherlands, and 3,383 from Spain. There were substantial differences in baseline characteristics between countries. There were small differences in ventilation management. Intensive care unit mortality was higher in Argentina and Brazil compared with the Netherlands and Spain (59.6% and 56.6% versus 32.1% and 34.7%; P <0.001). The median number of days free from ventilation and alive at day 28 was equally low (0 [0–7], 0 [0–18], 1 [0–16], and 0 [0–16] days, respectively; P = 0.03), and the median number of days free from ventilation and alive at day 60 was higher in the Netherlands and Spain (0 [0–37], 0 [0–50], 33 [0–48], and 26 [0–48] days, respectively; P <0.001). Propensity score matching confirmed the outcome differences. Thus, the outcome of COVID-19 ARDS patients in Argentina and Brazil was substantially worse compared with that of patients in the Netherlands and Spain. It is unlikely that this results from differences in case mix or ventilation management.
ABSTRACT.
Rwanda achieved unprecedented malaria control gains from 2000 to 2010, but cases increased 20-fold between 2011 and 2017. Vector control challenges and environmental changes were noted as potential explanations, but no studies have investigated causes of the resurgence or identified which vector species drove transmission. We conducted a retrospective study in four sites in eastern Rwanda that conducted monthly entomological surveillance and outpatient malaria care. We compared sporozoite rates, human blood index (HBI), and relative abundance of the primary vectors, Anopheles gambiae and Anopheles arabiensis, from 2017 to 2020. We then modeled the effects of vector control interventions, insecticide resistance, and temperature changes on species composition and reported malaria incidence. Sporozoite rates were 28 times higher and HBI was four times higher in An. gambiae compared with An. arabiensis. Insecticide-treated bed nets, first distributed nationally in 2010, were associated with decreased An. gambiae relative abundance. However, increased pyrethroid resistance was associated with increased An. gambiae relative abundance and malaria incidence. Epidemic malaria peaks corresponded to periods of model-predicted An. gambiae re-emergence, and increased regional air temperatures during the period were further associated with increased malaria incidence. Indoor residual spraying (IRS), implemented with non-pyrethroid insecticides later in the period, was associated with 86% reductions in An. gambiae relative abundance and 75% reductions in malaria incidence. These findings suggest that increased pyrethroid resistance and the re-emergence of An. gambiae were closely linked to the malaria resurgence in eastern Rwanda. Non-pyrethroid IRS or other control measures that effectively target An. gambiae may help prevent future resurgences.
Dengue virus (DENV) is transmitted to humans by mosquitoes of the genus Aedes. Although several molecules have been described as part of DENV receptor complex in mosquito cells, none of them have been identified. Our group characterized two glycoproteins (40 and 45 kD) as part of the DENV receptor complex in C6/36 cells. Because identification of the mosquito cell receptor has been unsuccessful and some cell receptors described for DENV in mammalian cells are heat-shock proteins (HSPs), the role of HSPs in DENV binding and infection in C6/36 cells was evaluated. Our results indicate that gp45 and a 74-kD molecule (p74), which interact with DENV envelope protein, are immunologically related to HSP90. Although p74 is induced by heat shock, gp45 apparently is not. However, these proteins are relocated to the cell surface after heat-shock treatment, causing an increase in virus binding without any effect on virus yield.
ABSTRACT.
In recent years, multiple reports have emerged describing real-time quantitative polymerase chain reaction (qPCR) detection of DNA derived from human parasite species in environmental soil samples. In one such report, sampling was focused in impoverished areas of the southeastern United States, and a link between poverty and the presence of parasite DNA in soil was proposed. Whether transmission of certain parasitic diseases persists in the United States in association with poverty remains an important question. However, we emphasize caution when reviewing interpretations drawn solely from qPCR detection of parasite-derived environmental DNA without further verification. We discuss here the limitations of using qPCR to test environmental DNA samples, the need for sampling strategies that are unbiased and repeatable, and the importance of selecting appropriate control areas and statistical tests to draw meaningful conclusions.
The American Journal of Tropical Medicine and Hygiene
The American Journal of Tropical Medicine and Hygiene is a peer-reviewed journal published monthly by the American Society of Tropical Medicine and Hygiene and consists of two complete, sequentially numbered volumes each calendar year.
Journal Affiliation: The American Journal of Tropical Medicine and Hygiene is the official scientific journal of the American Society of Tropical Medicine and Hygiene (ASTMH). The Society is a nonprofit, professional organization whose mission is to promote world health by the prevention and control of tropical disease through research and education.
Frequency: Monthly
Coverage: 1921 -
A Review of the Recent Epidemiology of Zika Virus Infection
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Electronic Clinical Decision Support Tools to Manage Patients with Lower Respiratory Tract Infection: Clinicians’ Perspectives in Sri Lanka
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Journal Facts
- Impact factor: 2019 Impact Factor is 2.126 : 5-year Impact Factor is 2.439.
- Manuscripts and number of pages published: Over 500 articles and 3,000 pages are published every year.
- Submissions: Over 1,000 submissions each year, mostly unsolicited, with 2/3 from outside the US.
- Turnaround time: Average time between submission and first decision is 40 days.
- Frequency: Monthly, with articles online ahead of print on a weekly basis.
- Circulation: Spans six continents with an average of 65,000+ monthly website visits.
Description
The American Journal of Tropical Medicine and Hygiene, established in 1921, is published monthly by the American Society of Tropical Medicine and Hygiene. It is among the top-ranked tropical medicine journals in the world publishing original scientific articles and the latest science covering new research with an emphasis on population, clinical and laboratory science and the application of technology in the fields of tropical medicine, parasitology, immunology, infectious diseases, epidemiology, basic and molecular biology, virology and international medicine. The Journal publishes unsolicited peer-reviewed manuscripts, review articles, short reports, images in Clinical Tropical Medicine, case studies, reports on the efficacy of new drugs and methods of treatment, prevention and control methodologies,new testing methods and equipment, book reports and Letters to the Editor. Topics range from applied epidemiology in such relevant areas as AIDS to the molecular biology of vaccine development. The Journal is of interest to epidemiologists, parasitologists, virologists, clinicians, entomologists and public health officials who are concerned with health issues of the tropics, developing nations and emerging infectious diseases. Major granting institutions including philanthropic and governmental institutions active in the public health field, and medical and scientific libraries throughout the world purchase the Journal. Two or more supplements to the Journal on topics of special interest are published annually. These supplements represent comprehensive and multidisciplinary discussions of issues of concern to tropical disease specialists and health issues of developing countries.
History
The American Journal of Tropical Medicine was published by the American Society of Tropical Medicine (ASTM) beginning in 1921. Thirty years later, the ASTM merged with the National Malaria Society (NMS) and the two organizations together became what is now known as the American Society of Tropical Medicine and Hygiene (ASTMH). In 1952 they published Volume 1 of the American Journal of Tropical Medicine and Hygiene (AJTMH). The archived journals of the National Malaria Society can be found here.