Onchocerciasis, or river blindness, is a neglected tropical disease (NTD) caused by the parasitic worm Onchocerca volvulus. It is transmitted through repeated bites by blackflies of the genus Simulium. The disease is called river blindness because the blackfly that transmits the infection lives and ...breeds near fast-flowing streams and rivers, mostly near remote rural villages. The infection can result in visual impairment and sometimes blindness. Additionally, onchocerciasis can cause skin disease, including intense itching, rashes, or nodules under the skin. Worldwide onchocerciasis is second only to trachoma as an infectious cause of blindness.
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When a person is infested with scabies mites the first time, symptoms typically take 4-8 weeks to develop after being infested. However, an infested person can transmit scabies, even if they do not have symptoms. Scabies usually is passed by direct, prolonged skin-to-skin contact with an infested pe...rson. However, a person with crusted (Norwegian) scabies can spread the infestation by brief skin-to-skin contact or by exposure to bedding, clothing, or even furniture that he/she has used.
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People with Guinea worm disease (GWD) have no symptoms for about 1 year. Then, the person begins to feel ill. Symptoms can include the following:
Slight fever
Itchy rash
Nausea
Vomiting
Diarrhea
Dizziness
A blister then develops. This blister can form anywhere on the skin. However, the blis...ter forms on the lower body parts in 80%–90% of cases. This blister gets bigger over several days and causes a burning pain. The blister eventually ruptures, exposing the worm. The infected person may put the affected body part in cool water to ease the symptoms or may enter water to perform daily tasks, such as fetching drinking water. On contact with water, the worm discharges hundreds of thousands of larvae into the water.
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based on the WHO Bench Aids for the diagnosis of intestinal parasites;
Tutor’s Guide: perform specific laboratory techniques; identify intestinal parasites by genus and species; quantify helminth eggs in faeces by Kato-Katz procedure.
Research and Reports in Tropical Medicine 2021:12 63–76 . This review focusses on the interactions between the etiologic agent of Chagas disease, Trypanosoma cruzi, and its triatomine vector.
This motion graphic shows how the kissing bug transmits the Trypanosoma cruzi parasite to humans and causes Chagas disease.
O Ministério da Saúde atualiza o Diagnosticar para Cuidar com o PLANO NACIONAL DE EXPANSÃO DA TESTAGEM PARA COVID-19 (PNE-Teste) que tem a finalidade de expandir o diagnóstico da covid-19 por meio do teste rápido de antígeno (TR-AG), para uso em indivíduos sintomáticos e assintomáticos, par...a monitorar a situação epidemiológica e direcionar os esforços desta Pasta ministerial na contenção da pandemia no território nacional.
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procédures : guide méthodologique
Massoda Tonye et al. Malar J (2018) 17:156
https://doi.org/10.1186/s12936-018-2284-7
Background: In 2011, the demographic and health survey (DHS) in Cameroon was combined with the multiple indicator
cluster survey. Malaria parasitological data were collected, but the survey period did not overl...ap with the high
malaria transmission season. A malaria indicator survey (MIS) was also conducted during the same year, within the
malaria peak transmission season. This study compares estimates of the geographical distribution of malaria parasite
risk and of the effects of interventions obtained from the DHS and MIS survey data.
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Taenia saginata is a zoonotic tapeworm that is of economic importance in countries where cattle are kept. The parasite is transmitted from human tapeworm carriers (taeniosis) to bovines (cysticercosis) by excretion of eggs or proglottids containing eggs into the environment via the stool. Bovines ca...n then ingest the eggs through contaminated feed or water. After ingestion, the eggs hatch and release oncospheres in the small intestines, where the oncospheres penetrate the intestinal wall to reach the blood circulation. This distributes them throughout the body, but primarily to muscle tissue, where they develop into cysticerci. For humans to become infected with T. saginata, raw or undercooked bovine meat or offal containing infective cysts must be consumed. Bovine cysticercosis has been associated with various environmental factors related to water sources, such as animals having access to surface water, flooding of pastures and proximity to wastewater sources.
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The major neglected tropical diseases, Taenia solium taeniosis/cysticercosis and schistosomiasis caused by Schistosoma mansoni or S. haematobium are presumed to be widely distributed in Africa. Taenia solium taeniosis/ cysticercosis has been reported as an emerging disease in different regions of Af...rica [1, 2], but currently the exact distribution remains unclear. Reported prevalences of T. solium taeniosis and cysticercosis in African countries are not extensive and are further complicated by the lack of ‘gold standard’ tests for diagnosis.
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Many countries have made significant progress in the implementation of World Health Organization recommended preventive chemotherapy strategy, to eliminate lymphatic filariasis (LF). However, pertinent challenges such as the existence of areas of residual infections in disease endemic districts pose... potential threats to the achievements made. Thus, this study was undertaken to assess the importance of these areas in implementation units (districts) where microfilaria (MF) positive individuals could not be found during the mid-term assessment after three rounds of mass drug administration.
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Dickson and Daniel discuss lymphatic filariasis caused by the helminths Wuchereria bancrofti and Brugia malayai.
Background: The human helminth infections include ascariasis, trichuriasis, hookworm infections, schistosomiasis, lymphatic filariasis (LF) and onchocerciasis. It is estimated that almost 2 billion people worldwide are infected with helminths. Whilst the WHO treatment guidelines for helminth infecti...ons are mostly aimed at controlling morbidity, there has been a recent shift with some countries moving towards goals of disease elimination through mass drug administration, especially for LF and onchocerciasis. However, as prevalence is driven lower, treating entire populations may no longer be the most efficient or cost-effective strategy. Instead, it may be beneficial to identify individuals or demographic groups who are persistently infected, often termed as being “predisposed” to infection, and target treatment at them.
Methods: The authors searched Embase, MEDLINE, Global Health, and Web of Science for all English language, humanbased papers investigating predisposition to helminth infections published up to October 31st, 2017. The varying definitions used to describe predisposition, and the statistical tests used to determine its presence, are summarised. Evidence for predisposition is presented, stratified by helminth species, and risk factors for predisposition to infection are identified and discussed.
Results: In total, 43 papers were identified, summarising results from 34 different studies in 23 countries. Consistent evidence of predisposition to infection with certain species of human helminth was identified. Children were regularly found to experience greater predisposition to Ascaris lumbricoides, Schistosoma mansoni and S. haematobium than adults. Females were found to be more predisposed to A. lumbricoides infection than were males. Household clustering of infection was identified for A. lumbricoides, T. trichiura and S. japonicum. Ascaris lumbricoides and T. trichiura also showed evidence of familial predisposition. Whilst strong evidence for predisposition to hookworm infection was identified, findings with regards to which groups were affected were considerably more varied than for other helminth species.
Conclusion: This review has found consistent evidence of predisposition to heavy (and light) infection for certain human helminth species. However, further research is needed to identify reasons for the reported differences between demographic groups. Molecular epidemiological methods associated with whole genome sequencing to determine ‘who infects whom’ may shed more light on the factors generating predisposition.
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The trematodes Fasciola hepatica (also known as the common liver fluke or the sheep liver fluke) and Fasciola gigantica are large liver flukes (F. hepatica: up to 30 mm by 15 mm; F. gigantica: up to 75 mm by 15 mm), which are primarily found in domestic and wild ruminants (their main definitive host...s) but also are causal agents of fascioliasis in humans.
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Parasites & Vectors volume 11, Article number: 264 (2018)
Dengue creates a staggering epidemiological and economic burden for endemic countries. Without a specific therapy and with a commercial vaccine that presents some problems relative to its full effectiveness, initiatives to improve vector... control strategies, early disease diagnostics and the development of vaccines and antiviral drugs are priorities. In this study, we present the probable origins of dengue in America and the trajectories of its spread. Overall, dengue diagnostics are costly, making the monitoring of dengue epidemiology more difficult and affecting physicians’ therapeutic decisions regarding dengue patients, especially in developing countries. This review also highlights some recent and important findings regarding dengue in Brazil and the Americas. We also summarize the existing DENV polymerase chain reaction (PCR) diagnostic tests to provide an improved reference since these tests are useful and accurate at discriminating DENV from other flaviviruses that co-circulate in the Americas. Additionally, these DENV PCR assays ensure virus serotyping, enabling epidemiologic monitoring.
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Parasites & Vectors volume 15, Article number: 389 (2022)
Dengue is one of the common arboviral infections and is a public health problem in South East Asia. The aim of this systematic review and meta-analysis was to evaluate the prevalence and distribution of dengue in SAARC (South Asian Associ...ation for Regional Cooperation) countries.
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