Malaria in Tanzania causes death and disease and has a "huge economic impact". There were approximately 11.5 million cases of clinical malaria in 2008. In 2007–08, malaria prevalence among children aged 6 months to 5 years was highest in the Kagera Region (41.1 per cent) on the western shore of Lake Victoria and lowest in the Arusha Region (0.1 per cent).