11 March 2021 - NW293
Wilson, Ms ER to ask the Minister of Health
(1)With reference to his reply to question 628 on 25 November 2020, and in view of the fact that Dichloro-Diphenyl-Trichloroethane (DDT) has been banned in 34 countries around the world because of the severe health risks it poses to persons, in particular to unborn foetuses and animals, and with evidence also showing that mosquitoes have become immune to DDT and pyrethroids, what are the reasons that the Republic is still using DDT; (2) whether his department has an awareness programme in place that advises citizens on the (a) use of DDT and (b) effects thereof on their health; if not, why not; if so, what are the relevant details?
1. The UNEP (United Nations Environmental Programme) DDT Expert Group in its eighth meeting reaffirmed the continued need for DDT for IRS (Indoor Residual Spraying)-based malaria vector control in specific settings. South Africa is one of these settings in which DDT is indicated for malaria control owing to high level pyrethroid resistance in the major malaria vector mosquito species Anopheles funestus. Two factors support the continued need for DDT. Firstly, an anticipated resurgence in malaria cases and deaths, as a consequence of the Covid-19 pandemic and cyclone Eloise, necessitates the use of DDT as a highly effective insecticide with proven efficacy over a very long period. Secondly, in South Africa DDT plays a role in resistance management via a mosaic strategy that also utilizes pyrethroid insecticides. New vector control products and tools are on the horizon and are expected to provide new modes of action for IRS as supplementary methods, but continued financing will be essential to support the epidemiological trials necessary to inform international and local policy.
2. In 2011, the World Health Organisation (WHO) published a review on the human health effects of DDT and its metabolites in relation to DDT use for malaria control. The conclusions were that relevant exposure scenarios for the general population in countries using IRS are not of concern, because DDT and DDE (Dichloro-Diphenyldichloro-Ethylene) serum levels in sprayed households were generally below potential levels of harm. Recent findings showed weak associations between exposure to DDT and its breakdown product DDE and symptoms and diagnoses of allergies from an IRS area in Vhembe, Limpopo Province, South Africa. Another recent study reported that prenatal exposure to DDT, in Limpopo, a communitybased education programme was developed to reduce insecticide exposure from IRS. Community presentation through drama and song were implemented in 16 IRS pilot villages. The results showed an increase in the attendees’ knowledge of precautions to take before and after spraying, suggesting that the approach has promise to limit exposure to IRS insecticides.
It is especially important to note however that all insecticides have potentially harmful effects on human health, but their use is nevertheless necessary for the control of malaria, a potentially fatal disease. It should also be noted that malaria vector control via the use of insecticides, especially DDT, has reduced malaria incidence in South Africa by at least 95%, enabling South Africa to adopt an elimination strategy that will ultimately require fewer amounts of insecticide as malaria control becomes more targeted.