Concomitant experimental co-infection by Plasmodium berghei NK65 and Ascaris suum downregulates immunological responses and impairs lung function

Ascariasis and malaria are highly prevalent parasitic diseases in tropical regions and often overlap in endemic areas, contributing to high morbidity and mortality rates in areas with poor sanitary conditions. Several studies aiming to correlate the effects of <i>Ascaris</i> infections with malaria have contradictory and inconclusive results. In this context, we investigated parasitological and immunopathological aspects of the lung in the experimental concomitant co-infection of <i>Plasmodium berghei</i> NK65 and <i>Ascaris suum</i> during larval ascariasis. The most important findings related to <i>P. berghei Nk65 and A. suum</i> co-infection results in downregulation of Th1, Th2, Th17 and Treg responses and alteration of larvae migration in the lungs associated with decrease of larvae recovered in the lung parenchyma and increase of larvae recovered in the airways, which reflected in the severe morbidity and mortality of the animals, associated with impaired lung function. Taken together, our results suggest that the presence of both parasites contribute to the compromised host immune response. The low immunological responsiveness and the loss of lung function of the co-infected animals are evidence of an advanced sepsis-like process, resulting in the early death of the animals.