NZ student helps Tonga fight mosquito-borne disease

Transcript

A New Zealand student has completed research in Tonga which he hopes the government will use to cut the risk of mosquito-borne disease.

Canterbury Masters student Tom Swan returned to Tonga last year after first visiting the kingdom in 2011 as a teacher.

Mr Swan told Koro Vaka'uta he set about collecting larvae on the islands of Tongatapu and Eua.

TOM SWAN: Mosquito larvae occur in aquatic habitats so anything using car tyres, pools, ponds, even abandoned toilets - anything which can pull water. So the larvae, which is called 'ikeikaavai' in Tongan, are quite a problem and a big highlight of my research was I identified there was quite an educational gap between quite a few of the Tongan people not realising that the ikeikaavai turned into the mosquito 'namu'. Namu being mosquito in Tongan. So that was quite a significant finding in my research talking to people going round to their properties and asking them 'oh, have you got any mosquito larvae?' and they're like 'no, no' and then I quickly learned a bit of Tongan and 'have you got any ikekaavai?' and they're like 'yeah, yeah!' but a lot of people didn't realise that the larvae turns into the adults and the adults are what bite people and transmits diseases such as dengue fever and chikungunya virus. It is really important to study these diseases in the mosquito particularly the ikeikaavai because that's where it all begins.

KORO VAKA'UTA: How will this or how has this helped the people of Tonga?

TS: It is a real case of educating the public as well as educating them not only about the ikeikaavai but also about habitats - so car tyres are really big problems. If you have ever tried to shake out a car tyre it is particularly difficult to get the water out and that is the water that the ikeikaavai use to breed in. So the reduction of car tyres throughout Tonga is really important - that is the number one habitat in which the ikeikaavai were found. Another highlight has been producing a pictorial identification key so identifying the different ikeikaavai - nice and simple and you can see what species have. There are different species which can have different diseases.

KV: Your work showed that there were up to nine species in Tonga including the Asian Tiger. What is significant about that finding?

TS: There has been a varied amount of research on different mosquito species within Tonga. Various numbers have existed - some have said six, seven, nine, 13 dating back to the 1900s. I believe that is also to do with misidentifying the species because the microscope you need is one point six times lens which probably until the 1990s, we haven't had. I also believe that could be to do with the introduction of these species one being the Asian Tiger mosquito and that's a notorious mosquito - notorious for chikungunya virus and dengue fever...So that's just highlighting the need for the objectives I talked about earlier - the education.