Murine malaria is associated with significant hearing impairment

Twenty mice were included in a standardized murine cerebral malaria model. Auditory evoked brainstem responses were assessed before infection and at the peak of the illness.A significant hearing impairment could be demonstrated in mice with malaria, especially the cerebral form. The control group did not show any alterations. No therapy was used.This suggests that malaria itself leads to a hearing impairment in mice.With more than 247 million cases in 2006 malaria is one of the most frequent infectious diseases world wide[1]. The most severe course of the human disease is caused by Plasmodium falciparum, leading to multi-organ disease. In particular cerebral malaria (CM) is potentially leading to a wide range of neurocognitive sequelae[2]. Furthermore, it has been shown that severe falciparum malaria may lead to an acquired language disorder[2].Language development in childhood needs an intact and perfectly functioning hearing system - from the outer ear canal to the sensory cerebral cortex. So far, in malaria research no dedicated and specific attention has been paid to the involvement of the inner ear. Only very few authors have reported an acquired hearing impairment possibly caused by falciparum malaria[3,4]. To shed light into this aspect, a cerebral malaria experiment in Plasmodium berghei ANKA infected C57BL/6J mice - a well defined model for severe/cerebral malaria - was performed evaluating the hearing threashold with auditory evoked brain stem responses (ABRs) before infection and at the peak of the disease[5,6].The primary aim of this study was to evaluate a possible change of the hearing threshold in mice with CM and malaria without cerebral involvement.The animal study conformed to the Austrian guidelines for the care and use of laboratory animals and were approved by the Austrian Ministry for Education, Science and Culture with the reference number do. Zl. A08/4102. Three different animal groups were studied. One group contains the mice suffering from