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

Video Miami Cubans Divided on New US Policy

While older, more conservative Cuban Americans have promoted anti-Castro political movement for years, younger generations say economically, it is time for change More

2014 Sees Dramatic Uptick in Boko Haram Abductions

Militants suspected in latest mass kidnapping of over 100 people in Gumsuri, Nigeria on Sunday More

Video Cuba Deal Is Major Victory for Pope

Role of Francis hailed throughout US, Latin America - though some Cuban-American Catholics have mixed feelings More

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Sudan School Becomes Target of Aerial Attacksi
X
December 19, 2014 12:45 AM
The school dropout rate is at an all-time high in Sudan's South Kordofan state because many schools have been destroyed during the three-year civil war between the government and SPLA-N rebel forces. Adam Bailes visited Sudan's Nuba Mountains' region and reports many children are simply too scared to go to school
Video

Video Sudan School Becomes Target of Aerial Attacks

The school dropout rate is at an all-time high in Sudan's South Kordofan state because many schools have been destroyed during the three-year civil war between the government and SPLA-N rebel forces. Adam Bailes visited Sudan's Nuba Mountains' region and reports many children are simply too scared to go to school
Video

Video VOA Reporter Tours Devastated Peshawar School

Islamist militants wearing military uniforms and strapped with explosives attacked a military run school Tuesday in the northwestern Pakistani city of Peshawar. At least 141 people were killed in the horrific attack, most of them young students. VOA reporter Ayaz Gul visited the devastated school and attended the funeral of the principal who courageously tried to save her students from the deadly attack.
Video

Video Nigerians Fleeing Boko Haram Languish in Camp Near Capital

In its five-year effort to impose Islamic law in northeastern Nigeria, the Boko Haram extremist group has killed thousands of people and forced hundreds of thousands to flee. Some of those who ran for their lives now live in squalor on the edges of the capital, Abuja. Chris Stein reports for VOA.
Video

Video Putin Says Russian Economy Will Emerge Stronger

Russian President Vladimir Putin has said his country's sinking economy will not only recover but also become stronger, despite falling oil prices and Western sanctions over Ukraine. VOA's Daniel Schearf reports.
Video

Video Detained Turkish Journalists Follow Teachings of US-Based Preacher

The Turkish government’s jailing of critical journalists has sparked international condemnation and is being seen as an effort to undermine the followers of an ailing Turkish preacher based in the United States. VOA religion reporter Jerome Socolovsky has more.
Video

Video ‘Anti-Islamization’ Marches Increase Tensions In Germany

Anti-immigrant rallies in Germany have been building in recent weeks, peaking Monday night in the city of Dresden where tens of thousands of people turned out to demonstrate against what they call the ‘Islamization’ of the West. Germany has offered asylum to more Syrian refugees than any other country, and this appears to have set off the protests. Henry Ridgwell reports from London.
Video

Video Aceh Rebuilt Decade After Tsunami, But Scars Remain

On December 26, 2004 there was an earthquake in the Indian Ocean so powerful it caused the Earth’s axis to wobble a few centimeters. Onshore on the island of Sumatra, the resulting tsunami was devastating. A decade later, VOA Correspondent Steve Herman reports from Banda Aceh, Indonesia, where although there is little remaining evidence of the physical devastation, the psychological scars among survivors remain.
Video

Video Refugees Living in Kenya Long for Peace in the Home Countries

Kenya is host to numerous refugees seeking safe haven from conflict. Immigrants from Somalia face challenges in their new lives in Kenya. Ahead of International Migrants Day (December 18) Lenny Ruvaga has more for VOA News from the Kenyan capital.

All About America

AppleAndroid