In the laboratory, mosquito eggs are collected from breeding cages containing 5,000 females and 1,600 males and injected with the wolbachia bacteria. Xi's facility has the capacity to breed up to five million mosquitoes a week.

While a female mosquito that acquires wolbachia by mating is sterile, one that is infected by injection will produce wolbachia-infected offspring. Dengue, yellow fever and Zika are also suppressed in wolbachia-injected females, making it harder for the diseases to be transmitted to humans.

Xi set up his 3,500 square meter (38,000 sq ft) "mosquito factory" in 2012 and releases the males into two residential areas on the outskirts of Guangzhou.

Xi said the mosquito population on the island has been reduced by more than 90 percent.
One villager on the island, 66 year-old Liang Jintian, who has lived there for six decades, said the study was so effective he didn't have to sleep with a mosquito net any longer.

"We used to have a lot of mosquitoes in the past. Back then some people were worried that if mosquitoes were released here, we would get even more mosquitoes," he said. "We have a lot less mosquitoes now compared to the past."

Eoin Treacy's view

Zika virus has been making headlines because it poses a risk to unborn children but yellow fever, dengue, West Nile virus and especially malaria all kill and/or debilitate more people and have been with us for eons. There have been headlines recently to the effect that malaria is the biggest killer in human history. When looked at in those terms, the efforts to control the spread of these diseases represent a major contributing factor in the potential for economic growth in high population countries residing in prime mosquito breeding territories. 

The Bill and Melinda Gates Foundation is investing heavily in developing a genetically modified solution to the problem of mosquito-transmitted disease and the above story represents another vector in that fight against these threats. Solving this problem would represent the removal of a major headwind to economic development in many of the world’s poorest countries. 

The Dow Jones Africa Titans 50 Index hit a medium-term low in January and has been consolidating mostly above the 200-day MA since April. It is now testing the region of the upper side of that range and a successful breakout would reassert medium-term demand dominance. The constituents of the Index are broadly broken into energy/resources companies, banks and consumer companies. While tracking a different index the Market Vectors Africa ETF has a relatively similar pattern. 

By comparison the UK listed Neptune Africa Fund received a significant boost from the Pound’s devaluation despite its 1.8% management fee and 5% front end load.