Hepatitis B virus (HBV) and the parasite that causes malaria, both remain health concerns of immense proportion. In certain parts of the world individuals frequently become infected with both pathogens, raising the question of how each disease might influence the course of the other.
In an established mouse model of HBV infection, Pasquetto et al. show that the presence of malarial parasites can profoundly influence the course of HBV infection. Expression of HBV genes in the liver was considerably diminished upon co-infection with the malarial parasite Plasmodium yoeli. Infection with both the liver and blood stages of the malaria parasite resulted in this anti-viral effect, which was closely associated with intra-hepatic inflammation. Although the induction of several proinflammatory genes was detected within the liver, only interferons a/b and g were identified as being critical for inhibiting HBV replication. This study may help to explain some of the protective effects of malaria on the course of HBV infection in man. -- SJS
J. Exp. Med. 192, 529 (2000).
