Why you don't need a mosquito net in Nairobi

It is clear: the mosquitoes in Nairobi do not transmit malaria. So then, what do they transmit?

But first: what type of mosquito is found in Nairobi?

Timothy Kibe is the Head of Malaria Unit in Nairobi County. He says: “We are an urban city and the vector that causes malaria – the Anopheles species – usually doesn't thrive in urban settings with polluted waters. Nairobi County conducted a survey in 2024 to determine mosquito species in the city: 99 per cent of the mosquitoes collected were of the Culex species – also known as Culicines.”

In the survey, only 0.3 per cent were Anopheles. The Aedes type were equally very low in numbers.

The survey mirrors another similar study done ten years ago by scientists from Daystar University.

Conducted in 2015, the study yielded 13 different mosquito species. Captured in a report titled ‘Mosquito diversity in the Nairobi – Kenya urban environment and implications for disease transmission’, it found Culex pipens to be the most common species – accounting for 97 per cent of 7,605 mosquitoes sampled.

‘No vectors of malaria were collected,’ the study concluded.

Effectively we can say Culex mosquitoes rule the capital city. “They are the brownish mosquitoes that you see in Nairobi,” Kibe says.

Are they dangerous?

According to WHO, Culicines can transmit Japanese encephalitis and West Nile fever – viruses that are yet to be pronounced cause for worry in Kenya.

Dr Mukoko Dunstan is a retired entomologist who worked at the Division of Vector borne Diseases at Ministry of Health. Currently he teaches Medical Entomology at University of Nairobi.

Based on the evidence he handled, the mosquitoes in Nairobi are close to 100 per cent harmless.

“There is no known disease they are transmitting within Nairobi – as at now. They are practically harmless in terms of causing or transmitting disease,” Mukoko says.

Kibe confirms that Nairobi County health experts have not flagged a disease linked to the mosquitoes domiciled in the city.

According to Mukoko, the use of a treated insecticidal mosquito is not necessary in Nairobi. However, for personal comfort, it would be advisable to sleep under the net.

“It is definitely important to sleep under the net because the mosquitoes sting painfully and can make night sleep quite uncomfortable. There are also people who have adverse allergic reactions to their stings. For your comfort, I would advise that you have a net over your sleeping area.”