Lockdown and flooding raise the risk of a spike in mosquito-borne diseases in Kenya

By Eunice Anyango Owino, Medical Entomologist at the School of Biological Sciences, University of Nairobi

As soon as the first case of COVID-19 was confirmed in Kenya, the government banned public gatherings of more than 15 people. Schools, colleges and universities were closed . Within two weeks, the whole country was placed under a dusk to dawn curfew. Movement in and out of the cities of Mombasa and Nairobi was restricted. Those not in essential services were encouraged to work from home and international flights were banned.

Many of these measures could affect the country’s ability to keep mosquito-borne diseases under control. And the restrictions have coincided with the long rainy season in Kenya. Rain increases mosquito breeding sites, vector density and thus transmission of mosquito-borne diseases. Some of the regions currently experiencing high rainfall are the same ones that are prone to mosquito-borne diseases.

For example, areas around Lake Victoria are endemic for Anopheles sp transmitted malaria, which usually spikes in the rainy season. The semi-arid counties like Pokot and Baringo are known for malaria spikes as well as outbreaks of Rift Valley fever, which is transmitted by flood water mosquitoes.

At the coast, outbreaks of dengue and chikungunya fevers transmitted by Aedes aegypti are also associated with the rainy season. Parts of Mombasa county, a malaria endemic zone that also recorded dengue outbreaks in recent years, are under lockdown, like the Old Town area.

There is particular concern about the confluence of these factors on malaria. The World Health Organisation’s modelling and simulations show that COVID-19 is likely to affect the fight against the disease. In a worst case scenario, of 75% disruption in the use of insecticide treated bed nets and access to treatment, more than 769,000 deaths could be reported in sub-Saharan Africa in 2020. This is double the number of deaths due to malaria in this region in 2018.

Increased risks

A number of factors related to the lockdown in the country combined with the floods are likely to contribute to a spike in malaria cases.

For example, people are being restricted to particular geographic areas. On top of this, flood victims have been converging in localised areas such as primary schools. The restriction of movement and the convergence of people from different areas into a localised place is likely to lead to high transmission of malaria.

A further danger is that COVID-19 could take up precious resources in the healthcare system, reducing the efficacy in handling mosquito-borne diseases like malaria. Unfortunately, the more the number of carriers in the environment, the higher the likelihood of spikes and outbreaks.

Likewise, there might be a reduction in measures – such as cleaning and draining of stagnant bodies of water and larvicide application in breeding sites – that are commonly taken to fight outbreaks of mosquito-borne diseases. This would obviously lead to a high density of vectors and thus extensive transmission.

In addition, there have been reports of people shunning health facilities for fear of getting infected with COVID-19. This may also lead to increases in malaria cases as people avoid seeking treatment. Such a scenario was reported in West and Central Africa during the Ebola epidemic.

What can be done

The best strategies to control mosquito-borne epidemics are to reduce the mosquito population and for people to avoid mosquito bites.

Modelling and simulation reports have shown that the most effective mosquito-borne disease control methods during lockdowns are those aimed at protecting localised population densities, like the use of insecticide-treated nets and indoor residual spraying.

This means that Kenya’s national and county governments should double their efforts in encouraging the use of insecticide-treated nets in mosquito-borne disease endemic zones. This should be combined with the distribution of free mosquito nets to homes and camps where displaced people have gathered.

The government should also spray homes and camps.

Additionally, the policy-makers could encourage people to be more proactive in using mosquito repellent creams, liquids, coils and mats in addition to mosquito nets to avoid mosquito bites.

The government must also ensure that malaria drugs are available and easily accessible as they encourage people to seek care for fever and suspected malaria.

Finally, the Kenyan government should seek additional funding. It could do this, for example, by calling on the Roll Back Malaria partners like the Global Fund to Fight AIDS, Tuberculosis and Malaria. These partners halved their 2018–2020 donations towards malaria programmes in Kenya.

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