West Africa has a history of severe, prolonged “mega-droughts,” according to a new study, and researchers say that another one is inevitable, although they can’t say when it might occur. Says lead researcher Tim Shanahan: “It’s disconcerting – it suggests we’re vulnerable to a longer-lasting drought than we’ve seen in our lifetime…. If the region were to shift into one of these droughts it would be very difficult for people to adapt; and we need to develop an adaptation policy” [BBC News].
The study, which examined sediment samples on a lake bottom to trace the climate history back 3,000 years, reveals that the infamous 1970s drought of the African Sahel region, which lasted several decades and killed more than 100,000 people, was actually a “minor” event…. “What’s disconcerting about this record is that it suggests the most recent drought was relatively minor in the context of the West African drought history” [New Scientist], says Shanahan. The researchers found that decades-long droughts similar to the 1970s event occur every 30 to 60 years, but that even more severe, century-long droughts have reoccurred as well. The most recent mega-drought began in 1400 and lasted until 1750, during which time forests grew up in dry lake beds.
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Before his plane even touched the ground, Pope Benedict XVI sparked a controversy on his first trip to Africa by denouncing the use of condoms and saying they even exacerbate the AIDS crisis. Despite insisting that the church is in the forefront of the battle against AIDS in Africa [AP], during his flight to Cameroon the Pope told reporters that AIDS is “a tragedy that cannot be overcome by money alone, that cannot be overcome through the distribution of condoms, which can even increase the problem” [BBC]. Instead, the solution lies in a “spiritual and human awakening” and “friendship for those who suffer” [AFP].
The seven-day pilgrimage is Benedict’s first trip as pontiff to Africa, the fastest-growing region for the Roman Catholic Church [AP]. But the Vatican’s controversial policy on condoms continues to be tested on a continent where AIDS has killed more than 25 million people since the 1980s [Reuters]. With an estimated 22 million people currently infected on the continent, Africa is home to approximately 67 percent of the world’s population living with AIDS, and claimed a full three-quarters of all AIDS deaths in 2007.
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The small band of Homo sapiens that left Africa around 60,000 years ago, taking the first steps on a journey that would eventually disperse humans all around the world, may have been composed mostly of men. A new analysis of DNA variations in contemporary humans indicates that non-Africans descend from a population that contained far more males than females [New Scientist].
In the study, published in Nature Genetics [subscription required], researchers compared genetic samples from present-day African, European, and Asian populations. They were looking at the chromosomes that determine sex (two X chromosomes in women, one X and one Y chromosome in men), as well as the other 22 chromosome pairs, which are the same in both sexes. They examined the rate at which mutations randomly spread through the X chromosome over dozens or hundreds of generations as compared to the mutation rate in other, non-sex, chromosomes [AFP].
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The nasty parasite known as Guinea worm that has plagued humans since the days of the ancient Egyptians is on the verge of being completely eradicated, former president Jimmy Carter declared on Friday. The Carter Foundation has led the effort against Guinea worm, which could soon be remembered as the second disease to ever be wiped out by human efforts, smallpox being the first. There have been fewer than 5,000 cases of the disease in six African countries this year, and on Friday Carter announced two new grants dedicated to wiping out the final hotspots: The British government has pledged $15 million, while the Bill and Melinda Gates Foundation will contribute $40 million.
Guinea Worm is one of the worst parasites you can get. The worms burrow inside of you, grow to almost three feet long, are incredibly painful, and finally pop out of the skin and have to be reeled out, inch by inch, over many days [The New York Times blog]. The parasites have been found in Egyptian mummies, and the official name for the infection, dracunculiasis, references an archaic-sounding pain: it’s Latin for “affliction with little dragons.” Doctors have no vaccines or medicine with which to combat the parasite; instead they rely on prevention to keep people from getting infected. However, humans are the only host for the parasite, so ending outbreaks in human populations would destroy the worm forever.
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The official death toll from the cholera outbreak in Zimbabwe has climbed to nearly 500, according to the World Health Organization. But doctors on the ground say the actual fatalities may be closer to 1,000, with more than 12,000 infected since the start of the outbreak in August. Severe shortages of clean water, food, and medicine have allowed the normally treatable illness to ravage the country. Poorer areas have been without running water for months and just this week, the government cut off water to the nation’s capital, Harare. “The country is reaching a catastrophic level, in terms of food, health delivery, education,” said Morgan Tsvangirai, the MDC [opposition party] leader. “Everything seems to be collapsing around us” [Times Online].
Authorities say they have run out of water-purifying chemicals and have therefore shut down the water system in an attempt to contain the waterborne disease. But without running water, sanitation systems are nonexistent and sewage lies in the open air. “Proper hygiene is the best protection against cholera and you can’t do that without clean water,” [BBC News] said Marcus Bachmann of Doctors Without Borders. Residents have resorted to digging shallow wells and using contaminated water despite the government’s warning to use only boiled water. “We are afraid but there is no solution, most of the time the electricity is not available so we just use the water,” resident Naison Chakwicha said [USA Today]. The Health Minister has even asked residents to stop shaking hands. “Although it’s part of our tradition to shake hands, it’s high time people stopped,” he said [CNN].
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New genetic evidence shows that people were first infected with the HIV virus around the beginning of the 20th century, and researchers say the virus was able to take hold in human populations because of the growth of colonial cities in sub-Saharan Africa at that time. The evidence comes from a newly discovered tissue sample taken in 1960 from an HIV-infected woman who lived in Leopoldville–the city now known as Kinshasa, the capital of the Democratic Republic of the Congo.
Lead researcher Michael Worobey says that the virus may have crossed over from chimpanzees to rural humans repeatedly in the timeframe he identified, from 1884 to 1924; however, it didn’t take off in human populations until people in sub-Saharan Africa crowded together in cities. When the team looked at the region’s political history, they were struck by parallels between HIV’s spread and population expansion. The first major cities – Kinshasa, Douala, Brazzaville, Yaounde, Bangui – were founded by European colonialists in the late 1800s. Their populations started booming around 1910. “I was stunned by the timing,” says Worobey. “I would bet that cities, and the high-risk [sexual] behaviours found in them, are necessary to allow one of these sporadic viral jumps to get a toehold in the human population” [New Scientist].
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