News / Science & Technology

Sex Matters for Sleeping Sickness Microbes

Dead tsetse flies are seen in a laboratory run by the International Livestock Research Institute in Ghibe Valley, 115 miles southwest of Addis Ababa, Ethiopia, June 1, 2002. (AP Photo/Sayyid Azim)
Dead tsetse flies are seen in a laboratory run by the International Livestock Research Institute in Ghibe Valley, 115 miles southwest of Addis Ababa, Ethiopia, June 1, 2002. (AP Photo/Sayyid Azim)


Joe DeCapua
Scientists are keeping a close eye on the mating habits of microscopic organisms, including those that cause African sleeping sickness. They say what happens between two parasites can have major consequences for humans

Researcher Wendy Gibson said when it comes to single-cell parasites known as trypanosomes, sex matters. They had once been thought to reproduce by splitting in half. But scientists say they have a sex life. 

“This is important because if they can mate, it means that they can swap genes around. For example, if you’ve got a strain of parasite that’s resistant to a drug and it mates with one that isn’t, then it can swap that gene into the one that’s sensitive to the drug. And then, of course, you’ve got a new parasite, effectively, that is also resistant to the drug. That’s dangerous,” she said.

Gibson is professor of protozoology at the University of Bristol.

“Sleeping sickness is a very nasty disease. It’s carried by tsetse flies in tropical Africa. And now, fortunately, the numbers, as recorded by the World Health Organization, have dropped to less than 10,000 recorded cases. But years ago it used to really devastate large populations,” she said.

She explained how the illness got its name.

“It’s called sleeping sickness because the parasite gets into the brain and causes people to go into a sort of semi-comatose state. So that they just appear to be sleeping all the time. And that stage of the disease you can only treat with some very unpleasant drugs. One of them is based on arsenic. So you can imagine that that doesn’t do you any good”

Sleeping sickness has been on the decline due to early diagnosis, thorough treatment and better control of the tsetse fly population. That’s good news. But Gibson said that a resurgence is always possible.

“A colleague once described sleeping sickness to me as the sleeping dragon. It never goes away because the problem is that there are animal reservoirs of the disease. So even if you haven’t got humans with the disease in an area, it may still be circulating in animals, for example, cattle or wild animals. And of course the tsetse fly is feeding on those in keeping that cycle of transmission going. And it may then, if you’re unlucky, transfer back into the human population,” she said.

Gibson said it’s important to understand sexual reproduction in microbes.

“It’s one of the reasons why we’re worried about the next influenza outbreak because influenza is caused by viruses, but they also recombine. OK, it’s not the same sexual reproduction process as we get in these parasites, but it’s the same intrinsic mechanism that you’ve got recombination of genes. And, of course, with flu, you get new recombinant strains. We don’t know how virulent they are and what kind of disease they’ll cause and how quickly they’ll spread.”

The study of mating microbes helps explain how diseases spread and how new strains are formed. That’s why what’s happening in Uganda is being closely watched.

“You’ve got in the north of the country the West African form of the disease and in the southeast you’ve got the East African form. The East African form has been spreading northwards. And one of the worries is that it will overlap with the West African form of the disease. Now, if those two parasites then mate together, obviously, we’re worried that they’ll create some sort of superbug that maybe cause more serious disease,” said Gibson.

Trypanosomes are part of a group of organisms known as protozoa. They also include microbes that cause such illnesses as leishmaniasis, which affects internal organs – giardiasis, an intestinal disorder – and trichomoniasis, which is a sexually transmitted disease.

You May Like

Video Egyptian Journalists Call for Press Freedom

Despite release of al-Jazeera journalists and others, Egyptian Journalist Syndicate says some remain imprisoned More

Turkey Survey Indicates Traditional Distrusts, Shift to the West

Comprehensive public opinion survey also found a large majority of those interviewed distrust all countries other than country’s neighbor, Azerbaijan More

Pakistan Court Upholds Death Sentence in Blasphemy Killing

Highest court upholds sentence of Mumtaz Qadri convicted of 2011 killing a provincial governor for criticizing country’s controversial blasphemy law More

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Making a Minti
October 07, 2015 4:17 AM
While apples, corn, and cranberries top the list of fall produce in the US, it’s also the time to harvest gum, candy, and toothpaste—or at least the oil that makes them minty fresh. Erika Celeste reports from South Bend, Indiana on the mint harvest.

Video Making a Mint

While apples, corn, and cranberries top the list of fall produce in the US, it’s also the time to harvest gum, candy, and toothpaste—or at least the oil that makes them minty fresh. Erika Celeste reports from South Bend, Indiana on the mint harvest.

Video Activists Decry Lagos Slum Demolition

Acting on a court order, authorities in Nigeria demolished a slum last month in the commercial capital, Lagos. But human rights activists say the order was illegal, and the community was razed to make way for a government housing project. Chris Stein has more from Lagos.

Video Self-Driving Cars Getting Closer

We are at the dawn of the robotic car age and should start getting used to seeing self-driving cars, at least on highways. Car and truck manufacturers are now running a tight race to see who will be the first to hit the street, while some taxicab companies are already planning to upgrade their fleets. VOA’s George Putic has more.

Video TPP Agreed, But Faces Stiff Opposition

President Barack Obama promoted the Trans-Pacific Partnership on Tuesday, one day after 12 Pacific Rim nations reached the free trade deal in Atlanta. The controversial pact that would involve about 40 percent of global trade still needs approval by lawmakers in respective countries. Zlatica Hoke reports Obama is facing strong opposition to the deal, including from members of his own party.

Video Clinton Seeks to Boost Image Before Upcoming Debate

The five announced Democratic party presidential contenders meet in their first debate next Tuesday in Las Vegas, Nevada. Former secretary of state Hillary Clinton continues to lead the Democratic field, but she is getting a stronger-than-expected challenge from Vermont Senator Bernie Sanders. VOA National correspondent Jim Malone has more from Washington.

Video Music Brings Generations Together

When musicians over the age of 50 headline a rock concert, you expect to see baby boomer fans in the audience. Boomer rock stars have boomer fans. Millennial rock stars have millennial fans. But this isn’t always the case. Take the Lockn’ Music festival which took place in mid-September in rural Arrington, Virginia. Here, Jacquelyn de Phillips discovered two generations of people who are considered quite different in the outside world, spending 4 days together in music-loving harmony.

Video Ukranian Artist Portrays Putin in an Unusual Way

As Russian President Vladimir Putin was addressing the United Nations in New York last month, he was also being featured in an art exhibition in Washington. It’s not a flattering exhibit. It’s done by a Ukrainian artist in a unique medium. And its creator says it’s not only a work of art - it’s a political statement. VOA’s Tetiana Kharchenko has more.

Video South Carolina Reels Under Worst-ever Flooding

South Carolina is reeling from the worst flooding in recorded history that forced residents from their homes and left thousands without drinking water and electricity. Parts of the state, including the capital, Columbia, received about 60 centimeters of rain in just a couple of days. Authorities warn that the end of rain does not mean the end of danger, as it will take days for the water to recede. Zlatica Hoke reports.

Video Russia’s Syria Involvement Raising Concerns in Europe

European nations are joining the United States in demanding that Russia stop targeting opposition groups other than the Islamic State militants as Russian warplanes continue to conduct raids in Syria. The demand came in a statement from Britain, France, Germany, Qatar, Saudi Arabia, Turkey and the United States Friday. VOA Europe correspondent Luis Ramirez reports.

Video Nano-tech Filter Cleans Dirty Water

Access to clean water is a problem for hundreds of millions of people around the world. Now, a scientist and chemical engineer in Tanzania (in East Africa) is working to change that by creating an innovative water filter that makes dirty water safe. VOA’s Deborah Block has the story.

Video Demand Rising for Organic Produce in Cambodia

In Cambodia, where rice has long been the main cash crop, farmers are being encouraged to turn to vegetables to satisfy the growing demand for locally produced organic farm products. Daniel de Carteret has more from Phnom Penh.

Video Botanists Grow Furniture, with Pruning Shears

For something a bit out of the ordinary to furnish your home, why not consider wooden chairs, crafted by nature, with a little help from some British botanists with an eye for design. VOA’s Jessica Berman reports.

VOA Blogs