Scientists find bacterium can halt dengue virus transmission

Apr 01, 2010

Dengue fever -- caused by a virus transmitted by mosquitoes -- threatens 2.5 billion people each year and there is no vaccine or treatment. New research by Michigan State University entomologists has found that a bacterium can stop dengue viruses from replicating in the mosquitoes.

"In nature, about 28 percent of mosquito species harbor Wolbachia bacteria, but the mosquitoes that are the primary transmitters of dengue, Aedes aegypti, have no Wolbachia in them," said Zhiyong Xi, MSU assistant professor of entomology and study author. "We found that Wolbachia is able to stop the from replicating. If there is no virus in the mosquito, it can't spread to people, so disease transmission can be blocked."

The research is published in the April 1 issue of the journal .

In earlier work, Xi and colleagues introduced the Wolbachia bacterium into Aedes aegypti mosquitoes by injecting with this parasite. They have maintained the bacterium in the mosquitoes in the lab for nearly six years because it is passed from mothers to offspring.

When a Wolbachia-infected male mates with an uninfected female, the bacterium causes a reproductive abnormality that triggers early embryo death. Wolbachia doesn't affect embryo development when a female contains the same Wolbachia as a male, so the bacterium can spread quickly, infecting an entire mosquito population.

The Wolbachia bacterium can't be passed from mosquitoes to humans.

Another report with similar results was recently published by Australian researchers, though the groups used different strains of the Wolbachia bacterium.

"The strain we used has a 100 percent maternal transmission rate and causes the mosquitoes to live slightly longer," Xi explained. "The strain the Australian researchers used causes the mosquitoes to die a bit sooner. There are advantages to both. The longer the mosquitoes live, the more likely they are to pass on the Wolbachia infection to their offspring and infect the entire population in a shorter timeframe. But if the mosquitoes die earlier, they can't bite people and transmit the dengue virus.

"In both instances, the results demonstrate the potential using the Wolbachia bacterium as a control method for dengue virus."

Xi and colleagues, including Guowu Bian, a post-doctoral research associate in Xi's lab who conducted much of the research for this study, are now working to understand how the Wolbachia stops the dengue virus from replicating in .

"Only when we know the mechanisms underlying Wolbachia-mediated viral interference, will we will be able to why it's happening and further improve the efficiency of the viral interference," he said.

While dengue fever is rare in the continental United States, Hawaii was the site of a dengue epidemic in 2001. Overall, about one-third of the world's population is at risk of contracting dengue fever and up to 100 million people are infected each year. While most people recover in about two weeks, the infection can turn into dengue hemorrhagic fever, which causes bleeding from the nose and gums and can be fatal.

Explore further: Ebola mistakes should serve a lesson says WHO

Related Stories

Scientists closing the zap on dengue fever

Jan 01, 2009

(PhysOrg.com) -- A mosquito-borne virus that each year harms up to 100 million people and kills more than 20,000 is a step closer to being controlled after a breakthrough by Queensland scientists.

Mosquito parasite may help fight dengue fever

May 01, 2009

Dengue fever is a terrible viral disease blighting many of the world's tropical regions. Carried by mosquitoes, such as Aedes aegypti, 40% of the world's population is believed to be at risk from the infect ...

Working to eradicate dengue fever

Apr 13, 2009

(PhysOrg.com) -- A research project led by University of Notre Dame biologist Malcolm J. Fraser Jr. may soon lead to the eradication of dengue fever, a mosquito-borne viral disease that annually infects more ...

Recommended for you

Ebola mistakes should serve a lesson says WHO

13 hours ago

The World Health Organization's chief admitted on Sunday that the UN agency had been caught napping on Ebola, saying it should serve as a lesson to avoid similar mistakes in future.

British Ebola nurse discharged from hospital

19 hours ago

A British nurse who contracted Ebola while working as a volunteer in Sierra Leone said she was "happy to be alive" as she was discharged from hospital on Saturday having made a full recovery.

Tide turning in Ebola fight after hard lessons

Jan 24, 2015

A top U.N. official in the fight against Ebola greeted just three patients at one treatment center he visited this week in Sierra Leone. Families in Liberia are no longer required to cremate the remains of ...

Just five Ebola cases left in Liberia: UN

Jan 24, 2015

The United Nations said on Saturday Liberia was dealing with just five remaining cases of Ebola, in the clearest sign yet that the country is nearing the end of the outbreak.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.