Projections suggested expansions in vector species that carry dengue for parts of Australia and New Zealand.

There are still important vector species which remain susceptible throughout their distribution for example,Anopheles darlingi, A.

"Besides," he added, "the public today wouldn't stand for eradicating vector species like raccoons."

The genus is divided into two subgenera: Akiba and Leucocytozoon - based on the vector species.

"It also occurs in skunks and foxes," he said, "but the primary vector species appears to be the raccoon."

Vertical transmission from mosquito to mosquito has also been observed in some vector species.

These include need for intermediate vector species (mosquito that cause malaria) or transfer of bodily fluid (such as transfusions, needle-sharing or sexual contact).

Some 20 vector species now show resistance to the organochlorine insecticides, DDT, BHC and dieldrin, and 10 of these are also resistant to organophosphates and carbamates.

The first step is to identify proteins that prevent the vector species from transmitting the pathogen.

In Central America and Mexico, the main vector species lives both inside dwellings and in uninhabited areas.