mBio, Vol. 6 Issue 2, March/April 2015
Available evidence demonstrates that direct patient contact and contact with infectious body fluids are the primary modes for Ebola virus transmission, but this is based on a limited number of studies. In this review, the authors address what we know and what ...we do not know about Ebola virus transmission. They also hypothesize that Ebola viruses have the potential to be respiratory pathogens with primary respiratory spread.
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This study, and similar studies in Kenya, Mozambique, Swaziland, Uganda, and Zambia is the outcome of close collaborative by a team in Swaziland, with technical and financial support from the UNAIDS Regional Support Team for Eastern and Southern Africa, UNAIDS Geneva, and the World Bank's Global HIV.../AIDS Program (Global AIDS Monitoring and Evaluation Team). The study entailed using existing data and collecting new data to better know the country's HIV epidemic, know the country HIV response and how funding was allocated, so as to improve the HIV response and strengthen prevention based on evidence on what works to prevent new infections.
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This policy brief has been developed in response to the contemporary challenge of antibiotic resistance (ABR). ABR poses a formidable threat to global health and sustainable development. It is now increasingly recognized that the systematic neglect of cultural factors is one of the biggest obs...tacles to achieving better health outcomes and better standards of living worldwide. Using a cultural contexts of health approach, the policy brief explores the centrality of culture to the challenge of ABR. The brief examines how the prescription and use of antibacterial medicines, the transmission of resistance, and the regulation and funding of research are influenced by cultural, social and commercial, as well as biological and technological factors. The brief moves beyond the ready equation of culture with individual behaviours and demonstrates how culture serve as an enabler of health and provide new possibilities for change.
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Given the current situation of the COVID-19 pandemic, countries are advised to continue adopting the TB diagnostic algorithms recommended by PAHO / WHO.
Despite the differences in the modes of transmission of TB and COVID-19, certain personal protection measures are relevant for both diseases. Rout...ine measures to protect yourself from TB should continue along with additional precautions to protect workers from COVID-19.
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In the context of an unprecedented event such as the COVID-19 pandemic, at present, the effectiveness of stringent social distancing and international traffic-related measures in decreasing the rate of spread of SARS-CoV-2, and related mortality, is inferred from empiric observations of their applic...ation in countries experiencing different transmission scenarios (e.g., Australia, China, Germany, Italy, New Zealand, and Spain). Such observations are consistent with and corroborated by mathematical models.
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High levels of storage iron may increase malaria susceptibility. This risk has not been investigated in semi-immune adolescents. We investigated whether baseline iron status of nonpregnant adolescent girls living in a high malaria transmission area in Burkina Faso affected malaria risk during the fo...llowing rainy season. For this prospective study, we analysed data from an interim safety survey, conducted six months into a randomised iron supplementation trial. We used logistic regression to model the risk of P. falciparum infection prevalence by microscopy, the pre-specified interim safety outcome, in relation to iron status, nutritional indicators and menarche assessed at recruitment.
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Le présent document est une mise à jour du document d’information scientifique publié le 29 mars 2020 intitulé Modes of transmission of virus causing COVID-19: implications for infection prevention and control (IPC) precaution recommendations et comprend les nouvelles don...nées scientifiques disponibles sur la transmission du SARS-COV-2, le virus responsable de la COVID-19.
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The Lancet Planetary Health Volume 5, ISSUE 7, e466-e478, July 01, 2021
Transmission of many infectious diseases depends on interactions between humans, animals, and the environment. Incorporating these complex processes in transmission dynamic models can help inform policy and disease control int...erventions. We identified 20 diseases involving environmentally persistent pathogens (ie, pathogens that survive for more than 48 h in the environment and can cause subsequent human infections), of which indirect transmission can occur from animals to humans via the environment.
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The arrival and rapid spread of the mosquito-borne viral disease Chikungunya across the Americas is one of the most significant public health developments of recent years, preceding and mirroring the subsequent spread of Zika. Globalization in trade and travel can lead to the importation of these vi...ruses, but climatic conditions strongly affect the efficiency of transmission in local settings. In order to direct preparedness for future outbreaks, it is necessary to anticipate global regions that could become suitable for Chikungunya transmission. Here, we present global correlative niche models for autochthonous Chikungunya transmission. These models were used as the basis for projections under the representative concentration pathway (RCP) 4.5 and 8.5 climate change scenarios. In a further step, hazard maps, which account for population densities, were produced. The baseline models successfully delineate current areas of active Chikungunya transmission. Projections under the RCP 4.5 and 8.5 scenarios suggest the likelihood of expansion of transmission-suitable areas in many parts of the world, including China, sub-Saharan Africa, South America, the United States and continental Europe. The models presented here can be used to inform public health preparedness planning in a highly interconnected world.
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Mosquito-borne diseases are expanding their range, and re-emerging in areas where they had subsided for decades. The extent to which climate change influences the transmission suitability and population at risk of mosquito-borne diseases across different altitudes and population densities has not be...en investigated. The aim of this study was to quantify the extent to which climate change will influence the length of the transmission season and estimate the population at risk of mosquito-borne diseases in the future, given different population densities across an altitudinal gradient.
The Lancet Planetary Health Volume 5, ISSUE 7, e404-e414, July 01, 2021
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August 26, 2021
https://doi.org/10.1371/journal.pntd.0009678
Buruli ulcer is caused by infection with Mycobacterium ulcerans. The disease is reported in more than 33 countries worldwide, but only about half of these countries regularly report data to WHO; most cases are reported from subregions of West and Central Africa. The mode of transmission is not known....
About half of those affected are children aged under 15 years; there is no gender difference. Diagnosis is based mainly on clinical and epidemiological characteristics. Of the four methods used for laboratory confirmation (microscopy, polymerase chain reaction (PCR), histopathology and culture), PCR is the most rapid and widely used. Other rapid methods for detection of mycolactone in lesions from suspected cases, such as fluorescent thin-layer chromatography, are under evaluation in four countries in Africa.
Research to develop point-of-care tests is in progress. Treatment of Buruli ulcer comprises 8 weeks of combined antibiotics (rifampicin and clarithromycin). Complementary therapies such as wound care, skin graft and prevention of disability are needed in some cases to ensure full recovery.
The target set by the World Health Organization (WHO) for control of Buruli ulcer is for countries to achieve a rate of case confirmation by PCR of at least 70%. All endemic countries have at least one PCR facility to support confirmation of cases. However, most countries in the WHO African Region have not been able to reach the target, and the rate of case confirmation has been declining
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In 2005, the World Health Organization (WHO) recognized Chagas disease (CD; Trypanosoma cruzi infection) as a neglected tropical disease (NTD) [1] and included it into the global plan to combat NTDs [2]. The Target 3.3 of the United Nations Sustainable Development Goals (UN/SDG) aims at ending the e...pidemics of NTDs by 2030 [3]. Mother-to-child (congenital/connatal) transmission is currently the main mode of transmission of T. cruzi over blood transfusions and organ transplantations in vector-free areas within and outside Latin America (LA). Based on recent demonstrations that congenital transmission can be prevented [4–7], WHO has shifted its objective, in 2018, from control to elimination of congenital CD (cCD).
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Trypanosoma cruzi is the etiological agent of Chagas disease (CD), considered one of the most important parasitic infections in Latin America. Between 25 and 90 million humans are at infection risk via at least one of multiple infection mechanisms. Under natural conditions, the principal transmissio...n modes are transplacental or via one of more than 140 hematophagous triatomine bugs (Reduviidae: Triatominae). Triatomines acquire the parasite from mammal reservoirs due to their obligate blood-feeding (albeit triatomines can also feed on non-reservoir vertebrates such as birds and reptiles). The disease burden for CD in the Latin America and Caribbean region, based on disability-adjusted life-years (DALYs), is at least five times greater than that of malaria, and is approximately one-fifth that of HIV/AIDS. In recent decades, CD has extended to other continents outside natural reservoir or vector distributions due to human migration, with a minimum estimated 10 million individuals infected worldwide.
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After 100 years of chemotherapy with impractical and toxic drugs, an oral cure for human African trypanosomiasis (HAT) is available: Fexinidazole. In this case, we review the history of drug discovery for HAT with special emphasis on the discovery, pre-clinical development, and operational challenge...s of the clinical trials of fexinidazole. The screening of the Drugs for Neglected Diseases initiative (DNDi) HAT-library by the Swiss TPH had singled out fexinidazole, originally developed by Hoechst (now Sanofi), as the most promising of a series of over 800 nitroimidazoles and related molecules. In cell culture, fexinidazole has an IC50 of around 1 µM against Trypanosoma brucei and is more than 100-fold less toxic to mammalian cells. In the mouse model, fexinidazole cures both the first, haemolymphatic, and the second, meningoencephalitic stage of the infection, the latter at 100 mg/kg twice daily for 5 days. In patients, the clinical trials managed by DNDi and supported by Swiss TPH mainly conducted in the Democratic Republic of the Congo demonstrated that oral fexinidazole is safe and effective for use against first- and early second-stage sleeping sickness. Based on the positive opinion issued by the European Medicines Agency in 2018, the WHO has released new interim guidelines for the treatment of HAT including fexinidazole as the new therapy for first-stage and non-severe second-stage sleeping sickness caused by Trypanosoma brucei gambiense (gHAT). This greatly facilitates the diagnosis and treatment algorithm for gHAT, increasing the attainable coverage and paving the way towards the envisaged goal of zero transmission by 2030.
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Objective
To estimate the prevalence of Chagas disease in pregnant women and the vertical transmission of the disease.
Methods
Observational studies were identified from eight electronic databases, and details on study design, population and prevalence of Chagas disease were extracted. The data... were pooled using a random-effects model, and choropleth maps were created based on geopolitical regions and countries.
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The objectives of the meeting were:
1. To update the current status of the disease transmission, country capacities and plans for tackling the disease.
2. To understand the epidemiology including disease distribution and risk, the models
for estimating under-detection, the geographical variati...ons of in clinical presentation,
the roles of domestic and wild animal reservoirs and the subsequent different
transmission patterns and control approaches, including vector control.
3. To update current research and development efforts for improving diagnostic and
treatment tools.
4. To define the goals for achieving the control of r-HAT, the need for a multisectoral
approach and to discuss the strategy for controlling r-HAT and the coordination
mechanisms.
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Soil-transmitted helminths (STH) affect 1.45 billion people worldwide, and high intensity infections are associated with anemia, undernutrition and impaired cognition, particularly among children. Mathematical models suggest it may be possible to interrupt the transmission of STH in a community by e...xpanding mass drug administration (MDA) from targeted high-risk groups (primarily school-aged children and women of child-bearing age) to all community members with high coverage. The DeWorm3 Project will test the feasibility of this approach to interrupting the transmission of STH using a series of cluster randomized trials in Benin, India and Malawi. Each study area (population 80,000) will be divided into 40 clusters and randomized to community-wide or standard-of-care targeted MDA for three years. Two years following the final round of MDA, prevalence of STH will be compared between arms and transmission interruption assessed in each cluster. The DeWorm3 trials will provide stakeholders with information regarding the potential to switch from STH control to a more ambitious and sustainable strategy.
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