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The World Mosquito Program has successfully prevented outbreaks of Dengue and Zika using a unique and effective method.

Mosquito. Gerald Yuvallos. CC BY-ND 2.0.

The World Mosquito Program (WMP) is an Australian-based nonprofit organization working to eradicate several diseases carried and spread by mosquitoes, specifically Dengue and Zika. About 50 million people per year contract Dengue, while there are roughly between 100,000 and 500,000 cases of Zika per year worldwide. Both Dengue and Zika are mosquito-born illnesses, but they have very different effects. Dengue has a wide range of symptoms, and in the worst cases, the disease can end in hospitalization and death. Dengue is primarily a problem in Asia, with 70% of global cases occurring in the continent, though cases have been reported in 129 countries total. There is a vaccine for Dengue, but regardless, Dengue is still a leading cause of death in certain places in Asia and South America.

Zika, on the other hand, rarely causes death, but it is known for causing birth defects if caught by pregnant women. In addition to issues for fetuses, if caught by teens or adults, Zika can cause Guillain-Barré syndrome, in which the body’s immune system attacks its nervous system, leading to nerve damage of differing severity. There is no vaccine for Zika, and thus, the World Mosquito Program’s work is necessary in this area.

The primary strategy for WMP is breeding mosquitoes that carry a specific bacteria—Wolbachia—which prevents the mosquitoes from spreading these diseases. Once WMP has bred the Wolbachia mosquitoes, they work with governments to determine a plan to disperse the mosquitoes. The goal is that eventually, the non-Wolbachia carrying mosquitoes will die out by natural evolutionary processes. This method has produced positive results multiple times. While it takes some time to see results, the Wolbachia method has been praised for the fact that it uses a naturally occurring bacteria. Thus, it has a minimal impact on the ecosystem. Though there are treatments for Zika and Dengue, there are very few prevention methods other than the Dengue vaccine, which makes the Wolbachia method unique in its field. While Dengue and Zika are both serious and dire diseases, the most well-known mosquito-borne disease is malaria. Zika and Dengue are spread by the same type of mosquito, while malaria is transmitted by a different type, which is why the Wolbachia method cannot be used for malaria prevention.

I had the opportunity to interview Christie Hubbard, the Director of Philanthropic Partnerships for WMP. She explained in a bit more detail how the Wolbachia method is carried out. Hubbard explained the function of the bacteria, and the surprising simplicity of the process, saying: “This bacteria, Wolbachia, renders the female unable to transmit disease… Because it naturally occurs we don’t have to modify it, and we literally breed mosquitoes.” These “Wolbachia mosquitoes” are then released (with governmental permission) into areas suffering from Dengue outbreaks, under the assumption that through natural reproduction eventually the disease carrying mosquitoes will die out.

In terms of the tangible impact that WMP has had, Hubbard gave a few examples: “We did a gold standard trial in Indonesia… it resulted in a 77% reduction in Dengue and an 80% reduction in hospitalizations, which is really big… We’ve also seen success in Australia, which is where we’re founded and there’s a lot of Dengue. That’s where the program really first started and where we really… we never say eradicate, but we eliminated Dengue.” The near elimination of Dengue in two countries is an extreme feat, and WMP’s website also lists some other countries in which their method has seen success, such as Mexico and Sri Lanka. In both of these countries, there have not been any Dengue outbreaks in the areas where the Wolbachia mosquitoes were released in the years following their release.

Wolbachia method is launched by Brazil Ministry of Health. Ministério da Saúde. CC BY-NC-SA 2.0.

An obvious complication to WMP’s approach is that they are an Australian-based organization going into other countries. Hubbard addressed this, saying, “Our intervention is really geared towards governments and countries, so that’s who we work with and not so much private individuals. So yeah, we just go in, we release the mosquitoes, but it’s not as simple as that. It takes a long time, you’ve got to get the eggs to the country—we’ve got an insectary in every country—and of course there’s a big piece with community engagement, because you don’t just walk into another country and say, ‘hi, we’re bringing in more mosquitoes’... and working very closely with the ministries of health, and government officials.” WMP works in conjunction with the governments and the health officials of the countries which they work in, trying to eliminate any disruption or possible harm to the local communities. WMP’s website also publicly lists the percentage of the population of each place it works in that supports their intervention.

Get Involved

In terms of getting involved with WMP, there are few volunteer opportunities outside of the places where they are currently working. However, their website does have a page listing the places where they have or are currently working. Another, more accessible way to get involved that doesn’t require money is by simply raising awareness for WMP, and for the issue of mosquito-borne illness in general. Following and promoting their instagram, or even just educating yourself further on the issue through reading articles and sharing them with the people you know is a way to get involved, as this issue is not a high profile one.

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Calliana is currently an undergraduate student at Boston University majoring in English and minoring in psychology. She is passionate about sustainability and traveling in an ethical and respectful way. She hopes to continue her writing career and see more of the world after she graduates.

A recently concluded clinical trial of a new malaria vaccine has shown a promising efficacy rate in the fight against the mosquito-borne disease. Conducted by researchers from Oxford University and the Clinical Research Unit of Nanoro, the new R21/MM vaccine showed an efficacy rate of 77% during a yearlong clinical trial of 450 children in Burkina Faso. The new shot boasts the highest efficacy rate of any malaria vaccine thus far.

One of the reasons why malaria remains such a prevalent disease in sub-Saharan Africa is because the nature of the disease makes it difficult to vaccinate against. Unlike smallpox, polio and COVID-19, all of which are viruses, malaria is caused by the Plasmodium parasite, which is spread through mosquitoes. Parasites are much more complex than viruses because they are living organisms, which makes them more difficult to target due to multiple life stages.

Worldwide, malaria infects over 200 million people annually

That said, R21/MM is unique in that it is a pre-erythrocytic vaccine, a type of vaccine which targets the Plasmodium parasite in its earliest stages of development. This means that R21/MM intervenes before the parasite multiplies in the liver and reaches the bloodstream, a stage in the parasite’s life cycle when no symptoms yet occur.

While R21/MM’s 77% efficacy rate is far lower than that of other vaccines—the smallpox vaccine is 95% effective, the polio vaccine is 90% effective in two doses and all three approved COVID-19 vaccines in the United States are at least 86% effective or higher in preventing severe cases of COVID-19—the new malaria vaccine retains the highest efficacy rate of any options to date.

The most widely used malaria vaccine, RTS,S, which has been used since 2016, only has an initial efficacy rate of 55% and requires booster shots. According to Vox, RTS,S requires four shots to be fully vaccinated initially, whereas the R21/MM vaccine only requires three, plus a booster shot the following year. While numerous required shots makes vaccine rollout difficult, the fact that the new malaria vaccine is significantly more effective than RTS,S and requires one less shot makes it a noteworthy breakthrough in the fight against malaria.

While malaria has been largely eradicated from much of the world, with the U.S. eliminating the disease by 1951 through the application of DDT to the interior surfaces of rural homes, the draining of wetlands and other mosquito breeding sites and the spraying of insecticides, sub-Saharan Africa has continued to be plagued by the disease. Worldwide, malaria infects over 200 million people annually and kills an average of 400,000, with 94% of global malaria cases in 2019 occurring in Africa.

While COVID-19 remains the most pressing global health issue for most countries, in Africa it is malaria which remains most serious.

A December 2020 report by The BMJ estimated that malaria deaths in Africa throughout 2020 would dwarf those caused by COVID-19. As of May 10, 2021, the entire continent of Africa has reported 124,715 deaths due to COVID-19 since the pandemic began, in comparison with the 386,000 deaths reported from malaria in 2019. As a result, malaria vaccines of any efficacy rate are desperately needed in most of sub-Saharan Africa.
According to Al-Jazeera, the researchers of the R21/MM vaccine plan to conduct final stage trials in about 4,800 children between the ages of five months and three years old in four malaria-prone African countries. Should the efficacy rate from the clinical trials remain consistent, R21/MM could finally begin the hard work of eradicating malaria.