Perhaps it’s too early to celebrate but scientists have reported a drop in the number of malaria-carrying mosquitoes from some parts of Africa, including Tanzania, Eritrea, Rwanda, Kenya and Zambia.
A report in the Malaria Journal says that the number of malaria cases is dropping fast but that declining numbers are not just down to the use of nets and insecticides.
‘For more than ten years we have been collecting and counting the number of mosquitoes in Tanzanian villages,’ said Professor Dan Meyrowitsch from the Department of Health Services Research at the University of Copenhagen. ‘The number in our traps fell from 5,300 in 2004 to just 14 in 2009, and these were from villages without mosquito nets.’
One theory about the declining numbers is that climate change is responsible. Not only have patterns of rainfall have been more chaotic in these regions of Tanzania, they’ve often fallen outside the rainy season, interfering with the development of the insects. Disease among the mosquitoes has also been put forward as an explanation.
However, without being able to confirm to the reasons behind the decline, the mosquitoes may soon bounce back without warning. This has prompted fears of an epidemic as children may no longer have natural immunity.
‘If the mosquito population starts coming up again, and my own assumption is that it will, it is most likely we will have an epidemic of malaria with a higher level of disease and mortality especially amongst these children who have not been exposed,’ said Meyrowitsch.