By Maxwell Awumah, GNA
Hohoe, Oct 08, GNA – Malaria parasites have
evolved to be most infectious at the time of day when mosquitoes feed, to
maximise the chances of spreading, research shows.
The finding explains why people with the
disease experience regular bouts of fever. These occur as the parasites that
cause malaria replicate in the bloodstream of infected people or animals, in
preparation for being picked up by a biting mosquito.
The study is the first to provide strong
evidence for this idea, which was first suggested 50 years ago, according to
its release copied to the Ghana News Agency.
As increasing use of bednets by people in
affected regions drives mosquitoes to feed during the day, malaria parasites
may also have to adapt their behaviour so that they are better able to spread
infection in the daytime, the results suggest.
Scientists from the University of Edinburgh
studied daily rhythms of malaria parasites and the mosquitoes that spread them.
In a lab experiment with mice, scientists used
light and darkness to separately alter the day and night times of mosquitoes
and malaria parasites. By feeding some insects during the day and others at
night, they learned how both the parasites’ ability to cause infection — and
the mosquitoes’ vulnerability to disease — varied depending on the time of
day.
Their results showed that cycles of fever in
malaria infection likely evolved to produce forms of the parasite that are
infectious to mosquitoes in sync with the insects’ feeding cycles. They also
showed that mosquitoes are more susceptible to infection in the daytime.
The study, supported by the Natural
Environment Research Council, the Biotechnology and Biological Sciences
Research Council, Wellcome and the Human Frontier Science Program, was
published in Proceedings of the Royal Society B.
Dr Petra Schneider, of the University of
Edinburgh’s School of Biological Sciences, said: “It has long been
suspected that malaria parasites time their replication to maximise their
chance of transmission by mosquitoes. Our findings lend valuable insight into
how this disease spreads, and could inform measures to control it.”
GNA