WHO allays fears over mosquito aerial spraying

A drone sprays pesticides in a potato farm in Gataraga Sector, Musanze District. The Government plans to start using drones in spraying mosquito prone areas by the end of this month. / File

Rwanda has turned to drones in spraying mosquito prone areas as it steps up efforts to eliminate malaria, a move that has attracted public scrutiny.

According to Rwanda Biomedical Centre (RBC), the pilot exercise is beginning in Gasabo District before being rolled out to other parts of the country by the end this year.

When this was revealed in media, many Rwandan raised concerns about likely effects of the insecticide to be applied.

Dr Emmanuel Chanda, the Project Officer of Vector Control Operations at the World Health Organisation (WHO) Regional Office for Africa has allayed those fears.

A non-insecticide intervention

Dr Chanda told The New Times that if a country is to use such an approach, it has to be based on a non-insecticide (non-chemical) interventions, for example, microbial larvicides (bacteria that are registered as pesticides for control of mosquito larvae in outdoor areas).

Rwanda is getting that one right. The spraying will employ biological rather than chemical components.

Rwanda Biomedical Centre (RBC) says they will use Bacillus thuringiensis serotype israelensis (Bti) – a group of bacteria used as biological control agents for larval stages of certain insects.

Bti produces toxins which are effective in killing various species of mosquitoes, fungus gnats, and blackflies while having almost no effect on other organisms.

A solution to insecticide resistance

According to Chanda, the WHO is advising countries to use non-insecticide interventions because the effectiveness of the traditional insecticide based methods like Indoor Residual Spraying (IRS) seem to be compromised by factors like insecticide resistance in vector populations.

The efficacy of mosquito nets is as well limited by the fact that some mosquito populations have adopted the behaviour of feeding (biting) from outdoors due to genetic mutations.

“With that, countries are encouraged to make sure that they approach vector control using an integrated system where interventions that are not affected by insecticide resistance are part and parcel of the package. That brings on board the use of larvicides,” he said.

He said that WHO is working around the clock with academia, industry, and research institutions to come up with more effective and innovative ways of dealing with vectors.

It is said that a few African countries, including Malawi, have successfully deployed the drones in mapping and spraying mosquito breeding areas.

The drones and manual spraying initiatives come to as an additional measure to other strategies against malaria, among which is the mass distribution of bed nets, malaria case management in communities where community health workers are equipped to screen and treat malaria, free malaria treatment for Rwandans in Ubudehe 1 and 2 social clusters, and indoor residual spraying in malaria-prone districts.

The latest official statistics on malaria in Rwanda point to increased home-based management rate managed by community health workers from 50 per cent in 2018 to 57.1 per cent in 2019.

Malaria incidence also decreased from 394 per 1,000 people in 2018 to 328 per 1,000 in 2019.

Globally, according to the WHO, in 2017 there were an estimated 219 million cases of malaria in 87 countries.

editor@newtimesrwanda.com

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