Skip to content

Last Spraying Day of the Season

The spraying season starts in August and finishes in February each year.

This year, to celebrate the last day of the season, we welcomed a group of scientists from around the world and took them to see our spraying programme in action. We drove 40 minutes north of Maputo to meet with sprayers who were working on the last houses of a village in the Marracuene area.

You may be wondering what we spray and why?

We do what is called IRS (Indoor Residual Spraying). The female mosquitoes, who transmit the parasite of malaria, tend to live indoors. You can recognise them by the way they sit on walls with their bottom higher than their head.

In order to deter the mosquitoes, hard-working sprayers spend 8 hours a day walking around villages and spraying insecticides inside people’s houses. The insecticide’s shelf life is short, so the whole process is repeated in every house, every year.

On this particular day, it was hot. More than 35’C and the sun was high in the sky – nice when you visit the beach, but not so nice when you spend your day in a thick suit carrying gear that weighs more than 15kg!

After a short brief, we were ready to rock and roll! It was time to get inside. Generally speaking, the villagers’ houses are dark, the walls are damaged and there is soot everywhere caused by the open stove. There are holes in the walls and no mosquito nets to cover them. In Mozambican cities, most windows have mosquito nets, but in villages like the ones we spray in they’re not commonplace.

So, here we were, putting into practice our spraying lessons under the close supervision of actual sprayers. Don’t let the seemingly simple technique fool you – you have to hold the spray exactly 30cm away from the wall at all times. Easy? NOT! If the insecticide isn’t applied properly and evenly, it won’t be effective.

The insecticide is environmentally safe and approved by WHO (the World Health Organisation), but you still need protection when spraying. It’s hot, humid and the smell of insecticide is strong. So, it’s no surprise that our visitors were completely soaked with sweat by the time they took their suits off! 


I think it’s safe to say everyone was humbled by the experience, and enjoyed sharing a cold beverage on the beach that evening.