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Over the past nine years, Uganda has participated in a series of preliminary research activities for prospective field testing of gene drive mosquitoes which studies have shown can control malaria mosquito populations.

A great deal of the research efforts have been conducted at the Uganda Virus Research Institute in Entebbe, entailing — among other things — gathering and examining mosquito reproductive cycles and behaviours in insectary facilities.

This year, Uganda is looking to continue on that research path by conducting field surveillance and laboratory test trials of the so-called 'friendly mosquito' technology developed by the British biotechnology company Oxitec.

In early January, an Oxitec team led by CEO Grey Frandsen expressed interest in partnering with Uganda's health ministry and the Uganda Virus Research Institute, specifically to produce non-biting, self-limiting, and non-persistent male mosquitoes to combat malaria.

The team met with President Yoweri Museveni at his home in Rwakitura, Kiruhura district.

The President was supportive of the partnership, stating that he would provide Oxitec with all the required support to develop a solution to combat malaria, which remains a major public health problem in Uganda, afflicting women like Harriet Wangota, 37, a smallholder farmer, mother of six and resident of Busukuya sub-county in Manafwa district.

President Yoweri Museveni with Oxitec officials ( Credit: President Museveni X handle)

Wangota says she has lost three children to malaria in the past four years.

Uganda currently has the world's highest malaria incidence rate of 478 cases per 1,000 population per year, according to the World Health Organization. 

The WHO also reports that it is the leading cause of sickness and death in Uganda and is responsible for up to 40 percent of all outpatient visits, 25 percent of hospital admissions and 14 percent of all hospital deaths. The malaria death rate in Uganda is estimated to be between 70,000 and 100,000 deaths per year; a toll that exceeds that of HIV and AIDS. 

It also remains the leading cause of death among Uganda's children under the age of five.

Collaboration

Professor Pontiano Kaleebu, the director of the Uganda Virus Research Institute, told New Vision that Oxitec was interested in collaborating with the Institute to develop a mosquito-friendly Anopheles funestus solution for Uganda.

“Oxitec has done excellent work in South America to control the dengue-carrying mosquitos. They wish to collaborate with us to develop an intervention for the Anopheles funestus mosquito, which transmits malaria in primarily arid locations throughout the year," says Kaleebu, who is also a professor of immunovirology at the London School of Hygiene & Tropical Medicine Uganda Research Unit.

"One of the reasons we are interested in collaborating with them is that the Uganda Virus Research Institute, which has a strong entomology department, is focused on developing capacity, particularly in genetic technology to control vectors for diseases."

Several Ugandan entomologists and molecular geneticists concur that the Anopheles funestus mosquito, which is known to be one of the main carriers of malaria in sub-Saharan Africa due to its anthropophilic (preferring to feed on humans over other animals) and endophilic (associating with humans and their home environment) characteristics, has emerged as a threat to the success of the country’s insecticide-based malaria vector control programmes.

Professor Pontiano Kaleebu, the director of the Uganda Virus Research Institute (Credit: Uganda Virus Research Institute)

Kaleebu says the funestus mosquito mostly rests and bites outdoors, and it continues to transmit malaria even in the dry seasons.

“Insecticide resistance in Anopheles funestus mosquito populations has increased significantly in recent years. It poses a threat to the country's malaria control efforts,” says molecular geneticist Elly Okwakol.

“In some parts of the country like Soroti in eastern Uganda, it has been found to be resistant to insecticides like bendiocarb and in some others, resistant to pyrethroid insecticides."

Oxitec’s chief strategy officer, Neil Morrison, told New Vision that the company is presently developing a new Friendly Anopheles Stephensi mosquito control solution to combat the growing threat of malaria in the Horn of Africa, where the Anopheles stephensi mosquito, which belongs to the same subgenus as the Anopheles gambiae mosquito (Africa’s primary malaria vector) has contributed to the region’s malaria resurgence since 2012.

The Anopheles stephensi mosquito is not the predominant malaria vector in Africa, but it has been discovered in seven African nations to date: Ghana, Nigeria, Djibouti, Kenya, Sudan, Ethiopia and Somalia.

Okwakol says the Anopheles stephensi mosquito’s capacity to breed in urban areas distinguishes it from other malaria-carrying mosquitos. 

“It is yet to be detected in Ugandan human settlements, where the Anopheles Gambiae and funestus are the most common malaria-carrying mosquito species, but fears have grown in recent years that it could spread to Uganda from Kenya.” 

Morrison says Oxitec is committed to delivering impact against mosquitoes that spread malaria, which kills over 600,000 people each year, the majority of whom are in Sub-Saharan Africa.

“People in Uganda face this threat, every year. We’re at a very early stage of developing a collaboration with the Uganda Virus Research Institute, which is a globally respected public health research institute. We hope to work with the Institute to develop solutions for malaria-transmitting mosquitoes for Uganda,” he says.

Morrison adds that the technology, which has not been met with any resistance anywhere, uses two simple genes that create safe, no biting, self-limiting and non-persistent male mosquitoes and is designed to disrupt the breeding cycles of mosquitoes and offer a workable substitute for insecticides in the control of mosquito populations.

“The Friendly Aedes which provides a targeted, safe and non-toxic method for the control of insect pests that spread diseases such as dengue, Zika, chikungunya and yellow fever, has proven highly effective and is now fully commercial in Brazil and delivering impact nationwide. In the US we have completed three years of pilots in the Florida Keys (with approvals from the Environment Protection Agency), and we are expanding our work now to Central America, the Horn of Africa and the Pacific.”

Last year, a groundbreaking pilot of the Friendly Aedes Mosquitoes demonstrated 96% suppression of Dengue spreading Aedes aegypti in urban communities in Brazil.

Kaleebu notes that in an era when the rest of the globe is turning to genetic technology to tackle problems, including diseases and to attain SDG3 which aims at reducing malaria case incidence and fatality by 90%, Uganda, with its current limits on genetic interventions, will find it difficult to ignore the trends.

While the Oxitec/Uganda partnership is still in its early phases, the one with Djibouti, where malaria mortality doubled to 15,900 between 2014 and 2022, according to the WHO’s 2023 World Malaria Report, is advancing quickly.

On January 14 this year, the country announced the importation of Oxitec’s self-limiting and Friendly Anopheles Stephensi mosquitos into dedicated, contained laboratories in Djibouti city, where the invasive Anopheles Stephensi mosquitos, which invaded Djibouti in 2012 have fueled an unprecedented rise in urban malaria cases over the last decade.

The first field experiments of the self-limiting and Friendly Anopheles Stephensi mosquitos, which were produced over three years and are reportedly being imported following regulatory approval, are scheduled to begin this year.

Oxitec has been conducting extensive field surveillance and mosquito biology studies in Djibouti since 2021.

Why the name 'friendly'?

According to Morrison, the name “friendly” was first applied to the mosquitoes by dengue-affected South American communities, who felt the male mosquitoes were good insects combating 'bad' disease-transmitting mosquitoes.

He told New Vision that the Friendly Anopheles stephensi mosquitoes carry the same genetic technology as the Friendly Aedes.

Neil Morrison, Oxitec’s chief strategy officer ( Credit: Mark Lord)

“Friendly mosquitoes carry two introduced genes. The first is a self-limiting gene, which prevents female offspring from surviving to adulthood. This means that we can produce male-only cohorts of Friendly mosquitoes. These males – which unlike females do not bite – are released into a community where they seek and mate with pest females. 

"As their offspring inherit the self-limiting gene, the female offspring cannot survive, and so with sustained presence of friendly males in a community, the target mosquito population is reduced,” says Morrison.

'No footprint'

Morrison says the technology, which has been the subject of more than 100 peer-reviewed scientific publications, offers a safe, environmentally friendly, and long-term solution to malaria. 

“The technology depends on mating and is highly specific to the target pest species, leaving non-target species like butterflies and bees unharmed. The introduced genes produce proteins that are non-toxic, so predators that feed on Friendly mosquitoes suffer no harm.

“And after releases stop, the self-limiting gene cannot persist in the environment for longer than a few generations. It leaves no footprint. More than one billion Friendly mosquitoes have been deployed to date, with no reports of negative impacts on people and the environment," he says.