Chagas disease in a wormy world

Resumen

Most hosts, including humans, are infected with multiple parasites. Helminth infection can bias the human immune response towards a T-helper type 2 over a type 1 response, impairing the host�s ability to control concurrent intracellular microparasite infections, such as Trypanosoma cruzi. We have revised literature with the aim to search evidence on the interactions between worms and T. cruzi, to ascertain if this co-infection could alter: i) the susceptibility to acquire Chagas disease; ii) the progression of the disease; and iii) the probability of congenital transmission. As a result of a human autopsy survey, people who harbored co-infection with cysticercosis and T. cruzi had a longer life expectancy than those who harbored only one of the two parasites or none, and Chagas disease was 10 times more frequent in patients co-infected with cysticercosis. Dogs suffering from Chagas disease only, showed impaired heart lesions compared with those presenting co-infection with Dirofilaria immitis. Chronic helminth infections in mice showed a significant influence in the susceptibility to T. cruzi. In primates co-infected with T. cruzi and helminths the differences found in T. cruzi seroprevalence and the infection profile were the result of concomitant helminth infections since all typed isolates were the same. Co-infections with helminths and T. cruzi can interact and influence the immune responses to and clinical outcomes of Chagas disease. Studies addressing these interactions are needed both in humans and animal models