May 16, 2013 3:41 pm
Pregnancy tests did not always come in an easy-to-use, sterile kit that provided almost immediate results. Less than a century ago, women had to rely upon frogs instead. In 1938, Dr. Edward R. Elkan wrote in the British Medical Journal:
The discovery of what is now known as the xenopus pregnancy test is based on experiments conducted by Hogben (1930, 1931), who observed that hypophysectomy produced ovarian retrogression, and the injection of anterior pituitary extracts ovulation, in the female South African clawed toad.
The African clawed frog, as its better known today, was imported around the world for its use in pregnancy tests. Doctors would ship urine samples to frog labs, where technicians would inject female frogs with a bit of the urine into their hind leg. The animals would be placed back into their tanks, and in the morning the technicians would check for tell-tale frog eggs dotting the water. If the female frog had ovulated, that meant the woman who provided the urine was pregnant and the pregnancy hormone, human chorionic gonadotropin, had kicked off ovulation in the frog. Researchers referred to this procedure as the Hogben test.
Among the 295 tests which I have done so far and in which 2,112 frogs were used I have not seen one clear positive that did not indicate a pregnancy. There were a few negative results which when repeated after a fortnight became positive, but I do not think that these can be regarded as failures.
Frogs were actually a great improvement on the previous means of testing whether or not a woman was pregnant. Welcome History describes:
Prior to Xenopus, female mice and rabbits had been used, but these had to be slaughtered, dissected and carefully examined for ovarian changes. Because toads were reusable and could be conveniently kept in aquaria, Xenopus made pregnancy testing practical on a larger scale than before.
Thousands of the frogs were exported across the world from the 1930s to 1950s for use as pregnancy testers.
Immunological test kits finally replaced Xenopus in the 1960s and were rapidly taken up by private companies and feminist organisations offering diagnostic services directly to women. The first over-the-counter home test was sold in pharmacies in the early 1970s, but it resembled a small chemistry set and so was not user-friendly. It was not until 1988 that the first recognisably ‘modern’ one-step-stick hit the shelves.
But the frogs’ legacy lives on. African clawed frogs can be found living around many urban centers today, where they were likely released into the wild after hospitals no longer had use for them. Additionally, the imported frogs are common pets, and no doubt some of those pets wear out their welcome and get chucked into a local stream or pond.
In 2006, researchers realized that the frog may be carriers for the deadly amphibian chytrid fungus, which has caused the extinction and decline of around 200 amphibian species around the world. Now, research published in PLoS One shows for the first time that populations of African clawed frogs living in California carry the fungus. The frogs can carry the disease for long periods without being affected themselves, so researchers suspect that they may be the original vectors that introduced the fungus around the world—a sort of revenge for being used as egg-laying research subjects for all those years.
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May 14, 2013 12:19 pm
Of the neglected tropical diseases, parasitic worms, or helminths, are one of the most common maladies. Diseases like this, caused by parasite or bacteria, kill around 534,000 a year, according to the CDC. These have been largely wiped out in developed countries, but they still persist in the poorest parts of the world. People pick up infections by walking or consuming bits of contaminated soil in areas where sanitation is poor. After a person becomes infected, he perpetuates the infection in others through feces teeming with worm eggs.
Treating the worms is usually straight forward, but doctors must first determine whether or not a person is infected. Microscopes are not always available in poor communities, however, since they are difficult to transport and break easily. To get around this, an international team of doctors have developed an impromptu microscope by sticking a cheap lens onto his iPhone using double-sided tape. The New York Times describes the contraption:
The invention, described recently in The American Journal of Tropical Medicine and Hygiene, was tested in Tanzania on 200 stool samples from children who had a mix of hookworms, roundworms and giant roundworms.
A three-millimeter ball lens was taped over the camera lens of an iPhone 4. The zoom was increased to maximum, and slides, with tape atop the samples, were pressed right up to the lens. A pen flashlight shone light through the slide.
The improvised microscope detected giant roundworm eggs 81 percent of the time, roundworm eggs 54 percent of the time and hookworm eggs 14 percent of the time. The latter parasite may evade detection because it produces fewer eggs which also tend to degrade quickly outside of the body, the Times writes.
In order for doctors to determine whether or not to treat a person or village with anti-helminth medication, they need to have a microscope that performs with at least 80 percent accuracy. Unfortunately, the iPhone scope delivered results at just 70 percent accuracy compared to a conventional microscope. But with increasingly high tech smartphone cameras frequently introduced, the Times points out, the iPhone may soon find its place as a diagnostic tool after all.
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May 2, 2013 3:34 pm
In Mozambique, it seems to be game over for rhinos. A wildlife warden in the Great Limpopo Transfrontier park—the only place where rhinos were still surviving in the southern African country—told AP that the last of the animals have been killed by poachers.
Elephants also could become extinct in Mozambique soon, the warden, Antonio Abacar, warns. He says game rangers have been aiding poachers, and 30 of the park’s 100 rangers will appear in court soon. “We caught some of them red-handed while directing poachers to a rhino area,” Abacar says.
In Asia, the hacked-off horns can fetch a price equivalent to more than their weight in gold. Traditional Chinese medicine holds that the ground horns have curative properties. (Science holds that they do not.) In China and Vietnam, the horns are also used as decorations or as aphrodisiacs.
Mozambique’s rhinos have been living on the edge of extinction for more than a century, when big game hunters first arrived and decimated populations. Conservationists there have painstakingly built the population up over the last few years, but poachers—who often have significantly more funding, manpower and resources than wildlife wardens—seem to have finally stamped out the country’s rhinos for good. Mozambique’s conservation director remains hopeful that a few stray rhinos may still exist, however.
For many wildlife wardens, the lure of money and the lack of legal deterrents, often proves too much to resist. AP describes the typical case:
A game ranger arrested for helping poachers in Mozambique’s northern Niassa Game Reserve said on Mozambican Television TVM last week that he was paid about $80 to direct poachers to areas with elephants and rhinos. Game rangers are paid between $64 and $96 a month, and though the guilty ones will lose their jobs, the courts serve as little deterrent to the poachers: Killing wildlife and trading in illegal rhino horn and elephant tusks are only misdemeanors in Mozambique.
According to the Wall Street Journal, Mozambique’s government is still working on legislation first drafted in 2009 which would impose mandatory prison sentences for people caught shooting wildlife.
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April 29, 2013 12:20 pm
In 2010 alone, malaria infected 219 million people, largely in tropical regions in Africa, South and Central America, Asia and the Philippines. That year, the disease, caused by a parasite carried by mosquitos, killed 660,000 people. Objectively, that’s a high number of deaths, but compared to the number of infections, it’s relatively low. Right now, powerful anti-malarial medication protects those millions of infected people. But, says the BBC, a new strain of the parasite has been found in Cambodia that resists the leading class of anti-malarial drugs.
The new strain, first identified in 2008, is resistant to artemisinin, a “frontline drug in the fight against malaria,” the BBC writes. Since it was first discovered, the resistant version of malaria has spread around Southeast Asia. Health organizations are working hard to contain the spread of the drug-resistant variety: if the drugs are rendered ineffective, the consequences could be dire for millions of people.
This isn’t the first anti-malarial to be rendered useless, either. “The history of antimalarial medicine,” says the Mayo Clinic, “has been marked by a constant struggle between evolving drug-resistant parasites and the search for new drug formulations.”
Modern political history is already intertwined with the history of anti-malarial medications, and if drug-resistant strains of malaria continue to spread, they could prompt far-reaching changes. The advent of the first anti-malarial, says Glencoe World History, enabled European imperialism into tropical regions worldwide.
“Before 1850, the fear of disease was a major factor in keeping Europeans from moving into Africa. Especially frightening was malaria, an often fatal disease spread by parasites. …By 1850, European doctors had learned how to treat malaria with quinine, a drug that greatly reduced the death rate from the disease. Quinine is a bitter drug obtained from the bark of the cinchona tree, which is native to the slopes of the Andes in South America.”
Cinchona trees were transplanted from South America to India, and a steady supply of the drug enabled Europeans to move across Africa.
“By the beginning of the twentieth century, more than 90 percent of African lands were under the control of the European powers. A drug found in the bark of Latin American trees, which were then grown in Asia, had been used by Europeans to make possible their conquest of Africa.”
Since then, multiple generations of anti-malarial medication have come and gone (and researchers are still announcing promising new leads). But any time a drug-resistant strain like the one in Cambodia develops, it’s worth keeping an eye on.
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April 23, 2013 1:15 pm
In South Africa, lion bones are selling for around $165 per kilo (2.2 pounds). That’s about $5,000 for a full skeleton. The skull is worth another $1,100, according to the Guardian.
Over the past several months, officials in South Africa have noticed a steady increase in the number of permits they’re issuing for export of lion bones from certified trophy dealers. Such establishments breed lions for the express purpose of allowing wealthy tourists to engage in a controlled lion hunt. After killing the animal, if the patron does not want its body or bones, the breeders can then turn a large profit by stripping the lion down and selling its parts to Chinese and Southeast Asian dealers. The Guardian explains:
In 2012 more than 600 lions were killed by trophy hunters. The most recent official figures date from 2009, certifying export of 92 carcasses to Laos and Vietnam. At about that time breeders started digging up the lion bones they had buried here and there, for lack of an outlet.
In China, Vietnam and some other Southeast Asian nations, lion bones serve as a stand-in for tiger bones. Practitioners of traditional Chinese medicine believe the bones help with allergies, cramps, ulcers, stomach aches, malaria and a host of other ailments. As with many other purported traditional Chinese medicine “cures,” tiger bones ground into a powder and mixed with wind is also said to boost a man’s sexual prowess.
Despite the lack of scientific proof this potion is very popular, so with tiger bones increasingly scarce, vendors are replacing them with the remains of lions. Traders soon realised that South Africa could be a promising source. It is home to 4,000 to 5,000 captive lions, with a further 2,000 roaming freely in protected reserves such as the Kruger national park. Furthermore such trade is perfectly legal.
But just because trade in legally-sourced lion bones is given the green light from the South African government does not mean illicit activities are not underway. One investigator told the Guardian that he estimates that the legal market only contributes half of the lion bones currently leaving the country. That means poaching is responsible for the rest.
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