Scientists are saying that it may not be a good thing that malaria-carrying mosquitoes in some parts of Africa are slowing disappearing. Figures also indicate that the incidence of malaria is dropping significantly in countries such as Tanzania, Eritrea, Rwanda, Kenya and Zambia. Researchers say that climate change and a disease among mosquitoes may have contributed to the recent low numbers of malaria-carrying mosquitoes. However, the exact reason remains unknown. The phenomenon has sparked concerns from scientists, who worry that if the mosquito number rises again in the future, there may be an epidemic of malaria, with people experiencing a higher level of the disease and mortality, especially for those who haven't been exposed to it.