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Chagas

Chagas disease, named after the Brazilian physician Carlos Chagas, who  discovered the disease in 1909, is a systemic parasitosis caused by the  Kinetoplastid protozoan Trypanosoma cruzi. Technically is a zoonosis,  highly prevalent among mammals infecting >100 different species of the  Southern American continent, the parasite is transmitted by triatomine  bugs, a type of reduviid bug also known as "kissing" bugs.   

Geographical risk:

Traditionally Chagas disease has been confined to the Americas where it has been endemic  for centuries, particularly in poor rural areas of many Latin American countries.  

Transmission

Chagas disease is not transmitted to the human host directly via the insect’s bite. The T. cruzi  is excreted into the bug’s faeces. The bug generally defecates on or near a person while  feeding on their blood, generally when the person is sleeping. Transmission occurs when  faecal material gets rubbed into the bite wound or into  a mucous membrane (for example, the eye or mouth),  enabling the parasite to enter the body. The infection  can also be acquired by blood transfusions,  congenital infections and by oral route.  

Pathology

The disease has a short, frequently asymptomatic, acute phase followed by a life-long chronic  condition that in 30-40% of cases results, over years or decades, in severe  physiopathological  alterations of the heart and GI tract that are invariably fatal if untreated.   Cardiac disease usually begins with conduction abnormalities such as right bundle branch  block and/or left anterior fascicular block, which may be followed years later by dilated  cardiomyopathy. Later cardiac disease is sometimes accompanied by apical aneurysm and   thrombus formation. 

Future trends

Migration of individuals within and outside of endemic areas and the introduction of  programmes to reduce transmission in endemic areas have resulted in a change in the  disease epidemiology. Hundreds of thousands of infected individuals now live in cities across  Latin America and in the United States, Spain, and other European countries. While the EU  currently has no mandatory screening policy for blood donations received from people from  endemic areas. Individual countries have introduced their own policies e.g. in France since  2007, all blood donated by “at-risk” individuals is screened for T.  cruzi antibodies, in Spain all  immigrants from endemic areas are screened for T. cruzi serology before being accepted, the  UK and Italy prohibit donation by individuals from areas where T. cruzi is endemic.  

References

http://www.cdc.gov/parasites/chagas/ last accessed 11th March 2014 Nicole Klein, Ivy Hurwitz, and Ravi Durvasula, “Globalization of Chagas Disease: A Growing Concern in Nonendemic Countries,” Epidemiology Research International, vol. 2012, Article ID 136793, 13 pages, 2012. doi:10.1155/2012/136793 Further information CDC_Centers for Disease Control and Prevention http://www.cdc.gov/parasites/chagas/biology.html http://www.cdc.gov/dpdx/trypanosomiasisAmerican/index.html

Neglected Infectious Diseases

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© IP Research Consulting 2014
Chagas Roma˝a's sign, the characteristic swelling of the eyelid, is a marker of acute Chagas disease. The swelling comes from bug faeces being accidentally rubbed into the eye.