Is Kenya ready to turn to technology to finally defeat malaria?­­

For decades, researchers have  tested and refined dozens of methods to combat malaria,  striving to outmaneuver  the resilient mosquito.  From deploying bed nets to developing indoor residual spraying, these strategies have formed the frontline defense against this persistent parasite.

Over the years, tactics like sleeping under a treated mosquito net and destroying mosquito breeding areas have become ingrained in our daily lives. Yet, malaria remains one of the deadliest diseases in Africa,  claiming nearly 600,000 lives annually,  the majority of whom are children under the age of five.

The disease is transmitted by the parasite Plasmodium falciparum, found in the female Anopheles mosquito, and  thrive in the warm, tropical climates found across much of the continent. The World Health Organization (WHO) indicates that 249 million cases of malaria occurred in just 85 malaria-endemic countries in 2022. Nine out of 10 of these deaths occurred in Africa.

Despite the development of new vaccines, and antimalarial drugs, progress in reducing malaria transmission, WHO says, has slowed.  Even in  some devoeloped countries where it was once a distant memory, the disease is making a comeback.

This resurgence is partly due to growing resistance to insecticides and drugs, coupled with climate change, which is altering the landscape of mosquito-borne diseases.

Dr Bernard Abongo, a medical entomologist at the Kenya Medical Research Institute  (Kemri) says while the use of treated bed nets and indoor spraying have proven effective in the prevention of malaria, evolving mosquito behaviours are now challenging these methods.

“Mosquitoes have developed resistance to pyrethrum-based pesticides and have altered their biting patterns, with some studies showing mosquitoes biting during the day,” he says.

It is this resistance against the backdrop  of thousands of infections that has given rise to a new yet controversial strategy in the fight against the disease—genetically modified mosquitoes.

Some scientists see this as an experiment that could potentially be a breakthrough in ending malaria while another quarter term it as an experimental technology that could have unforeseen future effects on the environment.

In May, Djibouti became the second country in Africa after Burkina Faso to release genetically engineered mosquitoes into the wild. This is due to a resurgence of malaria  cases.  In 2012,  Djibouti had just 27 cases of malaria.  By 2022,  data from WHO shows that the country had reported more than  70,000 new cases.

Species
The return of Malaria in Djibouti is attributed to the Anopheles stephensi mosquito species. This species is typically found in the Middle East and Asia but has since made landfall in Africa leading to a spike in malaria cases . Research shows that this particular species is rapidly spreading across urban areas.

“The challenge with this species is that it is transmitting malaria in towns which is a new phenomenon in a  continent where malaria cases are mostly reported in rural areas and this becomes a perfect storm of a public health crisis,” says Grey Frandsen, the Chief Executive Officer, Oxitec.

Oxitec is a UK-based firm commissioned by the Djiboutian government to develop genetically engineered mosquitoes. Dubbed a method that “uses mosquitoes to fight mosquitoes,” Oxitec’s genetic technology targets female mosquitoes, the primary culprits in malaria transmission.

Genetically modified (GM) mosquitoes are engineered to either reduce the mosquito population or to make mosquitoes less capable of transmitting malaria either through population suppression or population replacement.

For population suppression male mosquitoes are genetically altered so that when they mate with wild females, the offspring do not survive to adulthood. Over time, this reduces the overall mosquito population, thereby lowering the number of potential carriers of the malaria parasite.

In the population replacement method, mosquitoes are modified to make them resistant to the malaria parasite. The mosquitoes are then released into the wild where they breed with wild mosquitoes. The goal is for the malaria-resistant genes to spread throughout the mosquito population, reducing the transmission of the disease.

“With sustained releases of self-limiting male mosquitoes, the number of female mosquitoes in the population is reduced, and the local invasive mosquito population declines,” says Grey. He adds: “Targeting the female species population is intentional because they are the ones that carry the malaria parasite and transmit it.”

Initially, genetically modified mosquitoes were developed for the Anopheles aegypti species and have since been released to the wild in Brazil, Cayman Islands, Panama and India to control this species of malaria-spreading mosquitoes.

The first large-scale trial  took place in Brazil, where researchers successfully suppressed the mosquito population in targeted areas by over 90 per cent. Following the promising results, similar trials have been launched in other African countries including Burkina Faso and Mali.

The trials are closely monitored by local and international scientists, as well as regulatory bodies like WHO.

In the Djibouti case, Anopheles stephensi was targeted for the first time in Ambouli region, and further releases are expected to allow for data collection.

“We are preparing for full field pilots later in 2024 to early 2025 where we will begin generating data about its effectiveness. In Brazil, we are nationally scaling up commercial solutions with ‘friendly mosquitoes’. We are achieving over 90 per cent in areas where we target that particular disease vector. We have every expectation that our Anopheles stephensi solution will deliver the same type of effectiveness,” he offers.

“Our government’s objective is to urgently reverse malaria transmission in Djibouti which has spiked over the last decade, explains Dr Abdoulilah  Abdi, Health advisor to the President of Djibouti.

The  biotechnology company, Oxitec, shares that Uganda is also expected to follow in the footsteps of Djibouti.
According to Frandsen, the East African nation will be the first in Africa to fund the development of a bio-engineered mosquito to curb malaria infections.

The species targeted with this intervention is the Anopheles funestis mosquito linked to transmissions of malaria in Uganda. This mosquito thrives in large, permanent water bodies, such as lakes and ponds that remain filled during the dry season.

“We are going to use the same technology we have used with Anopheles Stephensi in Djibouti,” adds Frandsen.
As countries including Djibouti begin to adopt this technology, a critical question looms: Is it time for the rest of Africa to embrace genetically modified mosquitoes to finally turn the tide against malaria?

But, the uptake of this technology is not widespread in Africa, and Kenya is among the countries that are yet to employ the use  of genetically modified mosquitoes to combat malaria. However, last month,Kemri said that it will be partnering with  the Imperial College London to introduce the geneticaly engineered mosquitoes into the country.

This came three months after Kemri researchers  detected the  Anopheles stephensi in the Northern Kenya region. Eunice Owino, a medical entomologist at the University of Nairobi noted that the invasion of this particular breed could pose  a great challenge to the health system and hamper  Kenya’s effort in the fight against malaria.

“Anopheles stephensi can breed in cisterns, jerrycans, tyres, open tanks, sewers, overhead tanks, underground tanks and polluted environments. Furthermore, the mosquito is invasive. It spreads very fast to new areas. It can adapt to various climatic conditions, unlike the non-invasive malaria vectors whose survival in cold temperatures in high altitude areas is restricted,” she wrote on the Conversation.

Other countries like Tanzania, Burkina Faso, and Cameroon have ongoing studies on gene drive mosquitoes.
The Pan-African Malaria Control Association (PANMCA), a continental body working with African scientists to develop local capacity in malaria research by studying the various mosquito species that spread malaria has for years, championed for the best practices of mosquito control in Africa.

Prof Charles Mbogo, the association’s president says mosquitoes are responsible for the spread of over 70 per cent of vector borne diseases among them being malaria, Dengue fever, Rift Valley fever, Zika virus and Chikungunya.

“If you remove the root cause of the problem, then you will not have malaria ,” he remarks.

“For a long time, pyrethroids were the only insecticides used to treat bed nets before distribution. We now have mosquito nets coming in that are designed to have a greater impact against pyrethroid-resistant mosquitoes.Trials have been done Bungoma, Kakamega and Busia counties and this will now be expanded to include Homabay County.”

In 2021, WHO reviewed guidelines for testing genetically modified mosquitoes as a new tool for combating malaria and other diseases spread through mosquitoes. This, WHO believes, is an additional tool to the existing measures to combat malaria. These guidelines also include gene-drive mosquitoes whose ability to spread the malaria parasite has been stopped.

Technology

For there to be any testing of genetically modified mosquitoes, there has to be regulatory mechanisms within the country employing this technology such as the National Biosafety Authority here in Kenya. These regulations are in line with the Cartagena Protocol on Biosafety.

With climate change poised to exacerbate public health crises like malaria, scientists are increasingly focused on innovative solutions. Further, as rising temperatures and shifting weather patterns create more favorable conditions for malaria-carrying mosquitoes, traditional control measures are falling short.

“It’s a question of how fast can we do it because there is no choice. We have to advance our methods for controlling the parasites. Climate change is driving the spread of disease-carrying mosquitoes to new regions and territories at an unprecedented rate.

This rapid geographical shift pose significant challenges for public health, hence the urgent need for innovative solutions to combat the evolving threats posed by these resilient vectors,” Prof  Mbogo shares with Healthy Nation.

Other tools currently being tested to fight malaria-spreading mosquitoes include spatial repellants. This is being tested in Western Kenya, Malawi and Mali where an insecticide is hanged inside a house and the mosquitoes are repelled.

“We have found that mosquitoes do not just transmit malaria indoors at night, but also during the day outside the house and these spatial repellants hold so much potential,” says Dr Abongo.

There is also the use of Ivermectin, a worm and parasite medication for cattle. Studies have shown that this medication can be used to treat those suffering from elephantiasis which is transmitted by mosquitoes.

“A mass drug administration of Ivermectin for people living in an area prone to elephantiasis has shown that the mosquitoes that bite the medicated people do not live longer and as such malaria cases go down.

The results for this study will be released towards the end of the year once they are done with the analysis and the preliminary results are quite promising,” he shares.

In yet another study by WHO,  climate change will be responsible for at least 60,000 additional malaria deaths between 2030 and 2050.

Dr­­­­­ Abongo believes that researchers have yet to fully exhaust options in curbing the spread of malaria and  there are many avenues to explore. For Panmca, there is a battery of tools to combat malaria and it is up to countries especially in Africa to work out the best combination of tools to eliminate malaria in Africa.
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