samedi 20 mai 2017
CHAGAS DISEASE... ON EN PARLE CES JOURS DERNIERS ...USA
SOURCE ET SUITE
C' EST UNE MALADIE SOURNOISE, CAR ELLE PEUT ETRE INSTALLEE SANS ETRE DETECTEE DANS UN PREMIER TEMPS... ET SE REVEILLER QQ ANNEES PLUS TARD
POTENTIELLEMENT MORTELLE, ELLE SE PROPAGE AUX USA DU SUD AU NORD
(25 ETATS USA)
ET PEUT ETRE CONTRACTEE PAR LES ANIMAUX DOMESTIQUES
Chagas disease, also known as American trypanosomiasis, is a tropical parasitic disease caused by the protozoan Trypanosoma cruzi. It is spread mostly by insects known as Triatominae or kissing bugs. The symptoms change over the course of the infection. In the early stage, symptoms are typically either not present or mild, and may include fever, swollen lymph nodes, headaches, or local swelling at the site of the bite. After 8–12 weeks, individuals enter the chronic phase of disease and in 60–70% it never produces further symptoms. The other 30 to 40% of people develop further symptoms 10 to 30 years after the initial infection, including enlargement of the ventricles of the heart in 20 to 30%, leading to heart failure. An enlarged esophagus or an enlarged colon may also occur in 10% of people.
T. cruzi is commonly spread to humans and other mammals by the blood-sucking "kissing bugs" of the subfamily Triatominae. These insects are known by a number of local names, including: vinchuca in Argentina, Bolivia, Chile and Paraguay, barbeiro (the barber) in Brazil, pito in Colombia, chinche in Central America, and chipo in Venezuela. The disease may also be spread through blood transfusion, organ transplantation, eating food contaminated with the parasites, and by vertical transmission (from a mother to her fetus). Diagnosis of early disease is by finding the parasite in the blood using a microscope. Chronic disease is diagnosed by finding antibodies for T. cruzi in the blood.
Prevention mostly involves eliminating kissing bugs and avoiding their bites. Other preventative efforts include screening blood used for transfusions. A vaccine has not been developed as of 2013. Early infections are treatable with the medication benznidazole or nifurtimox. Medication nearly always results in a cure if given early, but becomes less effective the longer a person has had Chagas disease. When used in chronic disease, medication may delay or prevent the development of end–stage symptoms. Benznidazole and nifurtimox cause temporary side effects in up to 40% of people including skin disorders, brain toxicity, and digestive system irritation.
It is estimated that 6.6 million people, mostly in Mexico, Central America and South America, have Chagas disease as of 2015. In 2015, Chagas was estimated to result in 8,000 deaths. Most people with the disease are poor, and most do not realize they are infected. Large-scale population movements have increased the areas where Chagas disease is found and these include many European countries and the United States. These areas have also seen an increase in the years up to 2014. The disease was first described in 1909 by Carlos Chagas after whom it is named. Chagas disease is classified as a neglected tropical disease. It affects more than 150 other animals.
The CDC estimates that there are 300,000 cases of Chagas in the United States, with most of those contracted in other countries.
Some patients experience acute, sudden symptoms during the first two months of infection, when parasite numbers in the blood are at their peak, including fever, fatigue, rash, diarrhea and occasionally swollen eyelids. But whether acute or chronic, the majority of people remain symptom-free......
The kissing bugs behind the disease have also been reported in 25 US states, with the largest concentration in the South.
Hiding in blood
The research team analyzed data from more than 8,500 people who donated blood between 1996 and 2000 and compared mortality among people who tested positive and negative for infection with T. cruzi. Subjects were followed for up to 14 years.
Dr. Alvaro Acosta-Serrano, a parasitologist at the Liverpool School of Tropical Medicine in the UK, agrees with the research team that more attention needs to paid to the problem of forgotten or unknown infections.
"This increase in mortality (shown by the study) is not that shocking," he said. "Chagas is often mistaken with flu symptoms and then disappears. It can disappear for years then re-emerge as heart disease."
He believes more accurate diagnostics are needed to pick up infections in people who carry low levels of the parasite in their blood.
"If we don't detect it in time, they will continue spreading the disease," he said.