Malaria in Africa
The spread of the mosquito species Anopheles stephensi across Africa poses a significant problem to a continent already heavily burdened by malaria.
Most – 90% – of the world’s malaria deaths are on the continent.
The spread of An. stephensi is particularly concerning because the mosquito has a number of characteristics that make it difficult to control.
This species can thrive in urban areas and likes being near humans.
An. stephensi feeds on its vertebrate host both indoors and outdoors.
This reduces the impact of commonly used vector control methods such as insecticide-treated nets and indoor residual spraying.
Researchers from Djibouti reported the presence of An. stephensi in the Horn of Africa in 2012.
Until then it had not been found in Africa although it was known to be widespread in Southeast Asia and parts of the Arabian Peninsula.
What is Invasive Species?
An invasive species is an organism that is not indigenous, or native, to a particular area.
Invasive species can cause great economic and environmental harm to the new area
Many invasive species thrive because they outcompete native species for food
Many epidemics and pandemics have been driven by pathogens, hosts and vectors invading new areas.
Earlier examples
Black Death in 14th century Europe, caused by the invasion of rats carrying fleas infected with the plague.
Asian tiger mosquito (Aedes albopictus) and the yellow fever mosquito (Aedes aegypti) both carry dangerous diseases such as dengue, yellow fever and Zika.
The spread of these mosquito species into North America and Europe during the 1970s and 1980s was associated with large increases in these diseases.
Anopheles gambiae is one of the most effective malaria vectors in the world.
It invaded South America in the 1930s. This species rapidly established itself in Brazil, causing a malaria epidemic with an estimated fatality rate of 13%
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