The elusive malaria mosquito may have just played another masterstroke or finally thrown in the towel, but definitely it has scientists dancing in circles.

In Kenya, scientists and project managers believe nets, effective medicines and good management practices are responsible for a big drop in malaria cases but Tanzanians believe the mosquito has just disappeared.

Malaria is said to have declined by about 50 per cent in the last five years in several parts of Africa, including Kenya. Until now, the decline has been attributed to mass distribution of nets, more effective malaria drugs and better managed prevention measures.

But at the weekend, a Danish-Tanzanian research group tabled evidence showing that the malaria mosquito had disappeared from villages, even those without any organised control programmes.

For more than 10 years, the researchers collected and counted the number of mosquitoes in Tanzanian villages.

"The number in our traps fell from 5,300 in 2004 to just 14 in 2009, and these were from villages without mosquito nets," says the lead researcher, Prof Dan Meyrowitsch of the University of Copenhagen, in a statement.

These findings, he says, suggest that the pronounced decline in malaria mosquito vectors is not a consequence of bed net use or indoor residual spraying.

Prof Meyrowitsch explains that the 99 per cent fall in the malaria mosquito population during the end of the 1990s seems to be connected to a fall in the amount of rainfall received. This, he says, may be due to global climate changes.

While the researchers are categorical about the declining number of malaria mosquitoes they are not sure why this is happening and are suggesting more research be carried out.