Concomitant Infection with <i>Leishmania donovani</i> and <i>Plasmodium berghei </i>Causes Pro-inflammatory Polarization Resulting in Malaria Exacerbation in BALB/c Mice

Abstract

Malaria and visceral leishmaniasis coexist in the same geographical regions. However, dual co-infection with parasites causing these diseases and their impact on public health is poorly documented. Interactions between these parasites may play a role in disease outcome. The present study set out to evaluate the clinical and immunological parameters following Leishmania donovani and Plasmodium berghei co-infection in BALB/c mice. Mice were divided into four groups; L. donovani- only, L. donovani-P. berghei, P. berghei- only and naïve. Body weight, parasite burden, total IgG, IFN-γ and IL-4 responses were determined. To determine the survival rate, four mice were used from each group. Tissues for histological analysis were taken from spleen, liver and brain. Results indicated significant differences in body weight (PL. donovani parasite load (P), L. donovani IgG (PP. berghei parasitemia (P= 0.0222), P. berghei IgG (P= 0.002), IFN-γ (PL. donovani parasite load and IgG responses in single or dual infections, while there was a positive relationship of P. berghei parasitemia and IgG responses in the dual infection group only. Plasmodium berghei had the highest mortality rate compared to L. donovani- only and L. donovani- P. berghei infected mice groups. Histological analyses showed enlarged red and white pulps and pathological changes in the spleen, liver and brain tissues which were less pronounced in co-infected group. We conclude that L. donovani and P. berghei co-infection reduces disease severity and these changes seem to correlate with variation in serum IgG and cytokines (IFN-γ and IL-4). Therefore, the study recommends the importance of inclusion of early screening of malaria in Visceral Leishmaniasis patients in regions where malaria is co- endemic.