Triatomines

Several transmission mechanisms exist for Chagas disease in humans including transfusions, congenital factors, oral or buccogastric transmission, and principally, via vectors. This last via occurs when humans are bitten by infected insects, mainly triatomines such as T. infestans, which defecate on the skin. When the individual scratches the location of the bite, the contaminated insect feces enter the bloodstream. 

According to Coura and Dias (2009), the transmission mechanisms for Chagas infection can be divided into two groups (i) the principal mechanisms, by means of vectors (triatomines), blood transfusion, oral transmission, contaminated food and placental, or birth canal transmission and (ii) secondary mechanisms, by means of laboratory accidents, management of infected animals, organ transplants, sexual transmission, wounds, contact with sperm or menstrual fluid contaminated with T. cruzi and, hypothetically, deliberate criminal inoculation or contamination of food with the parasite (Coura and Dias, 2009). 

Yaeger (1971), in Lousiana—United States, demonstrated that opossums acquired T. cruzi infection by eating two infected triatomine insects (R. prolixus). According to Yaeger (1971), mammals such as the opossum, armadillo, racoon, skunk, and various rodents which acquire T. cruzi infection frequently do so as a result of their insectivorous habits and occasionally through predation of infected mammals. Still in the United... 

In Brazil, Ezequiel Dias in 1933 was the first to officially describe the oral transmission mode of Chagas disease. He observed armadillos feeding on the insect P. megistus in his laboratory. This researcher also confirmed the importance of the transmission of the protozoa to cats that fed on infected insects and mice (Ribeiro et al., 1987). Additionally, Ribeiro et al. (1987) described the infection of several opossums (Didelphis albiven-tris) by oral means by feeding them either on infected triatomines or on mice experimentally infected by T. cruzi. Souza et al. (1997) infected mice by oral administration of blood samples contaminated with T. cruzi. 

So, there are many potential sources of food contamination and not only agai juice or sugarcane juice must be considered as high-risk food. Any human food source items (e.g., fruits) can be contaminated, in areas where there is a reservoir of T. cruzi in wild animals and/or infected triatomine insects, if unsafe food-manufacturing practices (e.g., harvest, transport, storage, and handling) are used. 

Juarez, M. P. and Fernandez, G. C. (2007). Cuticular hydrocarbons of triatomines. Comp. Biochem. Physiol., 147A, 711-730. 

Euglenozoa (Excavata) Trypanosoma cruzi Heteroxenous (vectorborne, large wild reservoir) Yes (food contaminated with triatomine or their dejections) Rare Insect vector, blood transfusion, organ transplantation, tranplacental way... 

The triatomine bug which causes Chagas disease can be trapped by using synthetic samples of its communication pheromone, which consists of a 4 1 mixture of the enantiomers of this heterocycle. How would you synthesize the required mixture of enantiomers Why would the other diastereoisomer of this compound be more of a challenge to make ... 

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