Transmission Chagas disease

rhodnius prolixus principal vector in colombia, venezuela, guatemala, honduras, , parts of nicaragua , el salvador.

in chagas-endemic areas, main mode of transmission through insect vector called triatomine bug. triatomine becomes infected t. cruzi feeding on blood of infected person or animal. during day, triatomines hide in crevices in walls , roofs.

the bugs emerge @ night, when inhabitants sleeping. because tend feed on people s faces, triatomine bugs known kissing bugs . after bite , ingest blood, defecate on person. triatomines pass t. cruzi parasites (called trypomastigotes) in feces left near site of bite wound.

scratching site of bite causes trypomastigotes enter host through wound, or through intact mucous membranes, such conjunctiva. once inside host, trypomastigotes invade cells, differentiate intracellular amastigotes. amastigotes multiply binary fission , differentiate trypomastigotes, released bloodstream. cycle repeated in each newly infected cell. replication resumes when parasites enter cell or ingested vector. (see also: life cycle , transmission of t. cruzi)

dense vegetation (such of tropical rainforests) , urban habitats not ideal establishment of human transmission cycle. however, in regions sylvatic habitat , fauna thinned economic exploitation , human habitation, such in newly deforested areas, piassava palm culture areas, , parts of amazon region, human transmission cycle may develop insects search new food sources.

t. cruzi can transmitted through blood transfusions. exception of blood derivatives (such fractionated antibodies), blood components infective. parasite remains viable @ 4 °c @ least 18 days or 250 days when kept @ room temperature. unclear whether t. cruzi can transmitted through frozen-thawed blood components.

other modes of transmission include organ transplantation, through breast milk, , accidental laboratory exposure. chagas disease can spread congenitally (from pregnant woman baby) through placenta, , accounts approximately 13% of stillborn deaths in parts of brazil.

oral transmission unusual route of infection, has been described. in 1991, farm workers in state of paraíba, brazil, infected eating contaminated food; transmission has occurred via contaminated açaí palm fruit juice , garapa. 2007 outbreak in 103 venezuelan school children attributed contaminated guava juice.

chagas disease growing problem in europe, because majority of cases chronic infection asymptomatic , because of migration latin america.