Most people hate mosquitoes — but scientists are about to build a "mosquito factory" to release modified (改良的) mosquitoes.

The modified mosquitoes carry a bacterium called Wolbachia pipientis (沃尔巴克氏菌), which can be naturally found in most insect species. However, it's rarely discovered in mosquitoes. "We actually grow these mosquitoes that contain the bacterium," Scott O'Neill, an Australian scientist involved in the project, told CBC News. When the modified mosquitoes are released, they slowly spread the bacterium to the population.

Several studies have demonstrated the insects' success. For example, a controlled experiment in Indonesia showed that the modified insect helped reduce the cases of the disease dengue (登革热) by 77 percent, according to a study paper published in 2021.

The World Mosquito Program has announced that it will release modified mosquitoes in many of Brazil's urban areas over the next 10 years. The aim is to protect up to 70 million people from diseases such as dengue, an infectious disease mainly spread by mosquitoes.

Brazil has one of the highest rates of dengue infection in the world, according to the Nature website. "More than 1,000 people died of dengue in 2022 because of the spread of mosquitoes. It's going everywhere," Luciano Moreira, a scientist in Rio de Janeiro, Brazil, told CBC News.

Another way to prevent mosquitoes from spreading diseases is by producing genetically modified mosquitoes (GM). In 2022 the US Environmental Protection Agency approved the release of 2.4 billion GM mosquitoes in California and Florida.

According to the agency, GM mosquitoes carry two types of genes: a self-limiting gene that prevents female offspring (后代) from surviving to adulthood; and a marker gene that allows researchers to identify GM ones in the wild. After being released, GM mosquitoes lay eggs, so the genes are passed on to offspring. In this way, the number of female mosquitoes is reduced, therefore reducing the chance of spreading disease.