Medical News
Bacteria stops dengue in its tracks
Research shows the bacteria Wolbachia can prevent mosquitos from passing on viruses
Germ warfare is showing great promise in controlling the spread of mosquito-borne viruses , such as dengue , chikungunya , and zika .
Research by scientists in Southeast Asia has shown that infecting mosquitoes with a naturally occurring bacteria dramatically reduces their ability to transmit the diseases that can lead to death or infant deformity .
Seeking to find a way to stamp out dengue , which is endemic to countries in Southeast Asia where it infects millions of people each year , Malaysia ’ s Ministry of Health has been leading a multi-institutional investigation into the use of Wolbachia , a bacteria that is present in many insects and inhibits the transmission of dengue from the Aedes aegypti mosquito , the disease ’ s vector .
“ We ’ ve been using all kinds of approaches to control dengue over the years , usually with chemicals for fogging . But since chemicals haven ’ t been able to control it , we thought let ’ s get the mosquito to control the mosquito . Releasing mosquitoes is definitely a new strategy ,” Dr Nazni Wasi Ahmad , a research officer at the Malaysian Ministry of Health ’ s Infectious Disease Research Centre , told Global Health Asia-Pacific .
The Malaysian study will soon enter its third phase when it will release infected mosquitoes in more than 37 hotspots across the country . The researchers believe that this widespread prevalence will be sufficient to determine the success of the study and if it should form part of Malaysia ’ s anti-dengue strategy .
“ After we released the mosquitoes and monitored the frequency of infection , we noticed that most of them in each area had Wolbachia in them . We were amazed to see how fast it was spreading . In some places we found that 100 percent of mosquitoes were infected with Wolbachia after five months ,” said Dr Nazni .
“ What ’ s more , once you use Wolbachia , you don ’ t use insecticides in the areas where the infected mosquitoes are released , which makes a big cost difference ,” he explained . “ The beauty is that Wolbachia will spread by itself by multiplying in the environment . Infected mosquitoes will mate with wild mosquitoes and the progeny will go on from there .”
In another field study , scientists in Indonesia released Wolbachia-infected Aedes aegypti mosquitoes in Yogyakarta earlier this year , resulting in the number of infections being 77 percent lower than in untreated areas .
The study released some six million mosquitoes across an area of 13 square kilometres where they then infected other wild mosquitoes . The infected mosquitoes did not behave differently , nor did their population fall , but their capacity to transmit the virus that causes dengue was vastly reduced .
Since Wolbachia occurs naturally in as many as 75 percent of all insect species , infecting the Aedes aegypti should not adversely affect other insect populations .
The same method is also being applied in other countries where dengue is prevalent , with the aim of eliminating the disease as a public health concern . Dr Nazni said that the technique can also be applied to counter other Aedes-borne diseases .
“ We know that Wolbachia can tackle chikungunya and zika because lab studies have also shown that it does inhibit these viruses .
The study released some six million mosquitoes across an area of 13 square kilometres where they then infected other wild mosquitoes . The infected mosquitoes did not behave differently , nor did their population fall , but their capacity to transmit the virus that causes dengue was vastly reduced .
36 NOVEMBER 2020 GlobalHealthAsiaPacific . com