You can download all diagnostic reference resources from the website: http://www.cdc.gov/dpdx/az.html
Chapter 6 contents
Malaria
Human African trypanosomiasis (sleeping sickness)
American trypanosomiasis (Chagas disease)
Leishmaniases
Intestinal protozoan infections (parasitic diarrhoea)
Flukes
Schistosomiases
Cestodes
Nematode infections
Filariasis
...
Onchocerciasis (river blindness)
Loiasis.
Lymphatic filariasis (LF)
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Revista Médica del Hospital General de México, Vol. 81. Issue 3.Pages 154-164 (July - September 2018)
Chagas disease is a parasitic zoonosis caused by Trypanosoma cruzi, a protozoan whose transmission to humans is primarily vector-borne. It is estimated that 6–8 million people worldwide are inf...ected and that 65–100 million people are at risk of becoming infected. Its clinical spectrum is very broad. During the acute phase, non-specific manifestations develop that may go unnoticed. During the chronic phase, specific manifestations develop that are diagnosed late and increase the morbidity and mortality of those suffering from it.
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In areas of Mexico, Central America, and South America, where the Trypanosoma cruzi parasite is present in triatomine bugs, improved housing and spraying insecticide inside housing to eliminate the bugs has significantly decreased the spread of Chagas disease. Screening of blood donations for Chagas... is another important public health tool to help prevent spreading the disease through blood transfusions. Early detection and treatment of new cases, including mother-to-baby (congenital) cases, will also help reduce the burden of disease.
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Chagas disease is a tropical parasitic infection transmitted by crawling, blood-sucking insects (kissing bugs). You may have flu-like symptoms or none at all. But the disease can lead to life-threatening complications. With prompt treatment, most people with Chagas disease, also known as American tr...ypanosomiasis, recover fully.
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Chagas disease (CD), caused by the parasite Trypanosoma cruzi, affects ~6–7 million people worldwide. Significant limitations still exist in our understanding of CD. Harnessing individual participant data (IPD) from studies could support more in-depth analyses to address
the many outstanding rese...arch questions. This systematic review aims to describe the characteristics and treatment practices of clinical studies in CD and assess the breadth and
availability of research data for the potential establishment of a data-sharing platform.
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Epidemiology
Chagas disease (American trypanosomiasis) is caused by the protozoan parasite Trypanosoma cruzi, and transmitted to humans by infected triatomine bugs, and less commonly by transfusion, organ transplant, from mother to infant, and in rare instances, by ingestion of contaminated food or... drink.1-4 The hematophagous triatomine vectors defecate during or immediately after feeding on a person. The parasite is present in large numbers in the feces of infected bugs, and enters the human body through the bite wound, or through the intact conjunctiva or other mucous membrane.
Vector-borne transmission occurs only in the Americas, where an estimated 8 to 10 million people have Chagas disease.5 Historically, transmission occurred largely in rural areas in Latin America, where houses built of mud brick are vulnerable to colonization by the triatomine vectors.4 In such areas, Chagas disease usually is acquired in childhood. In the last several decades, successful vector control programs have substantially decreased transmission rates in much of Latin America, and large-scale migration has brought infected individuals to cities both within and outside of Latin America.
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This motion graphic shows how the kissing bug transmits the Trypanosoma cruzi parasite to humans and causes Chagas disease.
Chagas is a parasitic disease that affects over 6 million people in the
world. As the disease typically remains asymptomatic for years, new cases
often go unnoticed and unreported, and most people with the disease
are unaware of their condition. Less than 10% of people affected are
diagnosed and... the vast majority do not receive the treatment they need.
If not treated, Chagas may cause irreversible, life-threatening damage to
the heart and other vital organs.
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Schistosomiasis, also known as bilharzia, is a disease caused by parasitic worms. Although the worms that cause schistosomiasis are not found in the United States, people are infected worldwide. In terms of impact this disease is second only to malaria as the most devastating parasitic disease. Sc...histosomiasis is considered one of the neglected tropical diseases (NTDs).
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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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Chagas disease (CD) is caused by the parasite Trypanosoma cruzi, and it is endemic in Central, South America, Mexico and the
South of the United States. It is an important cause of early mortality and morbidity, and it is associated with poverty and stigma. A third of
the cases evolve into chronic... cardiomyopathy and gastrointestinal disease. The infection is transmitted vertically and by blood/organ
donation and can reactivate with immunosuppression. Case identification requires awareness and screening programmes targeting the
population at risk (women in reproductive age, donors, immunocompromised patients). Treatment with benznidazole or nifurtimox is most
effective in the acute phase and prevents progression to chronic phase when given to children. Treating women antenatally reduces but does
not eliminate vertical transmission. Treatment is poorly tolerated, contraindicated during pregnancy, and has little effect modifying the
disease in the chronic phase. Screening is easily performed with serology. Migration has brought the disease outside of the endemic
countries, where the transmission continues vertically and via blood and tissue/organ donations. There are more than 32 million migrants
from Latin America living in non-endemic countries. However, the infection is massively underdiagnosed in this setting due to the lack of
awareness by patients, health authorities and professionals. Blood and tissue donation screening policies have significantly reduced
transmission in endemic countries but are not universally established in the non-endemic setting. Antenatal screening is not commonly
done. Other challenges include difficulties accessing and retaining patients in the healthcare system and lack of specific funding for the
interventions. Any strategy must be accompanied by education and awareness campaigns directed to patients, professionals and policy
makers. The involvement of patients and their communities is central and key for success and must be sought early and actively. This review
proposes strategies to address challenges faced by non-endemic countries
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This review focusses on the interactions between the etiologic agent of Chagas disease, Trypanosoma cruzi, and its triatomine vector. The flagellate mainly colonizes the intestinal tract of the insect. The effect of triatomines on trypanosomes is indicated by susceptibility and refractoriness phenom...ena that vary according to the combination of the strains. Other effects are apparent in the different regions of the gut. In the stomach, the majority of ingested blood trypomastigotes are killed while the remaining transform to round stages. In the small intestine, these develop into epimastigotes, the main replicative stage. In the rectum, the population density is the highest and is where the infectious stage develops, the metacyclic trypomastigote. In all regions of the gut, starvation and feeding of the triatomine affect T. cruzi. In the small intestine and rectum, starvation reduces the population density and more spheromastigotes develop. In the rectum, feeding after short-term starvation induces metacyclogenesis and after long-term starvation the development of specific cells, containing several nuclei, kinetoplasts and flagella. When considering the effects of T. cruzi on triatomines, the flagellate seems to be of low pathogenicity. However, during stressful periods, which are normal in natural populations, effects occur often on the behaviour, eg, in readiness to approach the host, the period of time before defecation, dispersal and aggregation. In nymphs, the duration of the different instars and the mortality rates increase, but this seems to be induced by repeated infections or blood quality by the feeding on infected hosts. Starvation resistance is often reduced by infection. Longevity and reproduction of adults is reduced, but only after infection with some strains of T. cruzi. Only components of the surface coat of blood trypomastigotes induce an immune reaction. However, this seems to act against gut bacteria and favours the development of T. cruzi.
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Leishmaniasis is a parasitic disease that is found in parts of the tropics, subtropics, and southern Europe. Leishmaniasis is caused by infection with Leishmania parasites, which are spread by the bite of infected sand flies. There are several different forms of leishmaniasis in people. The most com...mon forms are cutaneous leishmaniasis, which causes skin sores, and visceral leishmaniasis, which affects several internal organs (usually spleen, liver, and bone marrow).
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Fascioliasis is an animal parasitic disease (in cattle and sheep, but also pigs, donkeys, Llamas and alpacas that can be transmitted to humans. The infection is caught when aquatic or semi-aquatic plants with the larvae of the worm attached to their stem or leaves are ingested raw or poorly cooked. ...Once in the human body, the worm lodges itself in the main bile ducts and is responsible for severe morbidity. Endemic areas are distributed globally, but some of the most affected communities are found in the Andean highlands of South America. Triclabendazole is the only drug recommended for prevention and treatment and is provided free-of-charge to endemic countries through WHO. It can be distributed in mass interventions when clusters of cases are detected.
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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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Leishmaniasis is found in people in focal areas of approximately 90 countries in the tropics, subtropics, and southern Europe. The ecologic settings range from rain forests to deserts. Leishmaniasis usually is more common in rural than in urban areas, but it is found in the outskirts of some cities.... Climate and other environmental changes have the potential to expand the geographic range of the sand fly vectors and the areas in the world where leishmaniasis is found.
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It is 101 years since Carlos Chagas discovered the parasite responsible for the disease that now bears his name. What progress has been made since this discovery? Here Julie Clayton gives the low-down on Chagas disease.
Chagas disease is a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi. It is a significant public health problem, affecting millions of people worldwide. And although it was described 110 years ago, only two old nitroheterocyclic drugs, benznidazole and nifurtimox, are cu...rrently available for the treatment of Chagas disease and both have several limitations. Besides the clear unmet medical need, many challenges preclude the development of new treatments, some of them related to a lack of understanding of the pathophysiology of the disease and parasite-host interactions. New knowledge and tools are becoming available, but the number of new chemical entities progressing through the preclinical pipeline is inadequate. Therefore, it is still uncertain whether safe, effective and accessible new drugs will be available in the near future. The Chagas disease research community must commit to even greater collaboration to ensure that patients eventually benefit from better treatments.
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