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)

Multimedia

Audio
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

US Gives Malaysia Questionable Upgrade in Human Trafficking Ranks

Malaysia’s upgrade seen as removing barrier to country’s participation in the US-led 12-nation Trans-Pacific Partnership More

Turkey, US Try to Establish Buffer Despite Differences

Coalition airstrikes in proposed zone would aim to drive out Islamic extremists, allowing targeted area to come under sway of anti-Assad rebels More

Video US: Millions Exploited by Vast Fortunes of Human Trafficking

State Department's annual report calls exploitation 'modern slavery,' brutalizing girls, women into prostitution and forcing men, women and children into low-wage jobs across the globe More

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
US Calls Fight Against Human Trafficking a Must Wini
X
July 28, 2015 12:21 AM
The United States is promising not to give up its fight against what Secretary of State John Kerry calls the “scourge” of modern slavery. Officials released the country’s annual human trafficking report Monday – a report that’s being met with some criticism. VOA’s National Security correspondent Jeff Seldin has more from the State Department.
Video

Video US Calls Fight Against Human Trafficking a Must Win

The United States is promising not to give up its fight against what Secretary of State John Kerry calls the “scourge” of modern slavery. Officials released the country’s annual human trafficking report Monday – a report that’s being met with some criticism. VOA’s National Security correspondent Jeff Seldin has more from the State Department.
Video

Video Iran Nuclear Pact Wins Few New US Congressional Backers

Later this week, President Barack Obama returns from a trip to Africa to confront a U.S. Congress roiled by the nuclear accord with Iran, an agreement that has received the blessing of the U.N. Security Council. Days of intensive lobbying and testimony by top administration officials have won few new congressional supporters of the pact. VOA’s Michael Bowman reports.
Video

Video Washington DC Underground Streetcar Station to Become Arts Venue

Abandoned more than 50 years ago, the underground streetcar station in Washington D.C.’s historic DuPont Circle district is about to be reborn. The plan calls for turning the spacious underground platforms - once meant to be a transportation hub, - into a unique space for art exhibitions, presentations, concerts and even a film set. Roman Mamonov has more from beneath the streets of the U.S. capital. Joy Wagner narrates his report.
Video

Video Obama Encourages Kenya to Fix Cultures of Corruption, Discrimination

President Barack Obama bid farewell to Kenya Sunday with a major speech at as stadium outside the capital Nairobi where he called on Kenyans to change the cultures of corruption and discrimination that can hold society back. VOA East Africa Correspondent Gabe Joselow has the story.
Video

Video Europe’s Twin Crises Collide in Greece as Migrant Numbers Soar

Greece has replaced Italy as the main gateway for migrants into Europe, with more than 100,000 arrivals in the first six months of 2015. Many want to move further into Europe and escape Greece’s economic crisis, but they face widespread dangers on the journey overland through the Balkans. VOA's Henry Ridgwell reports.
Video

Video Stink Intensifies as Lebanon’s Trash Crisis Continues

After the closure of a major rubbish dump a week ago, the streets of Beirut are filling up with trash. Having failed to draw up a plan B, politicians are struggling to deal with the problem. John Owens has more for VOA from Beirut.
Video

Video Paris Rolls Out Blueprint to Fight Climate Change

A U.N. climate conference in December aims to produce an ambitious agreement to fight heat-trapping greenhouse gases. But many local governments are not waiting, and have drafted their own climate action plans. That’s the case with Paris — which is getting special attention, since it’s hosting the climate summit. Lisa Bryant takes a look for VOA at the transformation of the French capital into an eco-city.
Video

Video Racially Diverse Spider-Man Takes Center Stage

Whether it’s in a comic book or on the big screen, fans have always known the man behind the Spider-Man mask as Peter Parker. But that is changing, at least in the comic book world. Marvel Comics announced that a character called Miles Morales will replace Peter Parker as Spider-Man in a new comic book series. He is half Latino, half African American, and he is quite popular among comic book fans. Correspondent Elizabeth Lee reports from Los Angeles.
Video

Video California Towns Welcome Special Olympics Athletes

Cities and towns in Southern California are greeting thousands of athletes who are arriving for Special Olympics, a competition for people with intellectual disabilities. The games will run from July 25th through August 2nd. VOA's Mike O'Sullivan reports from Pasadena, California, where athletes from Namibia, Singapore and Tanzania got a rousing welcome from local residents.
Video

Video Critics of Japan Defense Policy Focus on Okinawa

In Okinawa, many locals have long complained that Tokyo places an unfair burden on the tiny island by locating most of Japan's U.S. military bases there. As Japan's government moves toward strengthening and expanding the country's defense policies, opponents of those plans are joining local protesters in Okinawa, voicing concern about where the country is headed. VOA’s Brian Padden reports from Okinawa.
Video

Video IS Uses Chemical Weapons in Syrian Attack

Islamic State militants have added a new weapon in their arsenal of fear: chemical weapons. VOA Kurdish service reporter Zana Omer was on the scene within hours of a recent attack in Hasakah, Syria, and has details of the subsequent investigation, in this report narrated by Miguel Amaya.
Video

Video Historic Symbol Is Theme of Vibrant New Show

A new exhibit in Washington is paying tribute to the American flag with a wide and eclectic selection of artwork that uses the historic symbol as its central theme. VOA’s Julie Taboh was at the DC Chamber of Commerce for the show’s opening.
Video

Video Hoverbike Flying Toward Reality

Another long-standing dream of many technological inventors is quickly approaching reality: U.S.- and British-based firms are cooperating in the development of an individual flying platform they call a hoverbike. They say it may revolutionize the concept of flying, including in the U.S. military. VOA’s George Putic reports.
Video

Video As Japan Expands Defense Role, Protests Follow

The Japanese government is moving forward with a controversial security bill that would authorize the military to fight abroad for the first time since World War II. Leaders say it is critical to defend against rising threats from China and North Korea. VOA’s Brian Padden reports from Japan on the big changes ahead, and the opposition they are drawing.
Video

Video Replacing Poppies with Coffee in Myanmar

The remote mountains of Myanmar’s Shan state are home to the second-largest opium-producing region in the world. After a drop during the 2000s, production surged in the past eight years to feed an increasing demand for heroin in China. But farmers are now making less on the crop, and the U.N. is hoping many will make the switch to growing coffee. Daniel de Carteret reports for VOA from Taunggyi.

VOA Blogs