Andean valleys on the road between Oruro and Cochabamba, Bolivia. Anopheles mosquitoes usually inhabit regions of lower altitudes

Flickr/jimcintosh

[LA PAZ] Malaria cases have been reported on the Bolivian high plateau, confirming scientists' predictions that mosquitoes have adapted to a colder climate.

Scientists predicted last year that malaria would spread across the high plains (altiplano), home to one third of the country's population, after they discovered biological adaptations in the mosquitoes that transmit the parasite.

Now the appearance of four cases of the disease, announced by the Ministry of Health, has supported their predictions.

The cases, announced last month (4 November), were found in Oruro, western Bolivia, around 3,710 metres above sea level.

Marylin Aparicio, principal researcher on the three-year mosquito project that was reported last year, said that her team had studied the northeastern area of La Paz, also on the high plateau.

They demonstrated that some anopheles mosquitoes have adapted to living at altitudes between 2,620 and 3,590 metres — conditions very different from their usual environment: warm, tropical and subtropical regions below 2,600 metres.

They found that the tails of the Anopheles pseudopunctipennis, have become shorter. The mosquito can live in dirty water rather than the clean water it inhabits at lower levels. It can survive temperatures as low as eight degrees Celsius.

It may be that a new subspecies has emerged but this will not be clear until further research has been done.

"Now climate temperature has increased by 0.85 degrees Celsius in those areas. This has changed the ecosystem and has developed an environment suitable for the vector to live", said Aparicio.

In recent years, malaria has also emerged in parts of the East African highlands. According to a report published in the Proceedings of the National Academy of Sciences in 2001, a rise of half a degree in the region in the last 50 years may have doubled the number of malaria-carrying mosquitoes.