Ancient pterosaurs were skilled fliers

Posted 2009/08/05 at 2:49 pm EDT

RIO DE JANEIRO, Aug. 5, 2009 (Reuters) — A fossil found in China of a pterosaur, the earliest known flying vertebrate, shows the creatures had unique and complex wing fibers that enabled them to fly with the precision and control of birds, researchers said on Wednesday.

A model of a pterosaurs called the Jeholopterus ningchengensis is shown during a news conference at Rio's Federal University in Rio de Janeiro August 5, 2009. The model is on display with a 130-million year-old fossil of the Jeholopterus ningchengensis which was discovered in China. REUTERS/Bruno Domingos

The finding by a team of Brazilian, German, Chinese and British researchers backs up the theory that the reptiles that dominated the skies from up to 220 million years ago, also known as pterodactyls, were not just basic gliders.

A new technique that involves shining ultra-violet rays on the well-preserved fossil found in Inner Mongolia brought out a detailed view of the tissue in the pterosaur's wing, researchers said at a news conference on Wednesday in Rio de Janeiro.

They also found hair-like fibers different from any other animal's that covered the creature's body and part of its wings. This could have helped the animals control their body temperature and shows they were warm-blooded, said Alexander Kellner, a paleontologist at Brazil's National Museum in Rio.

"They are different from other furs we find in mammals and they provide us another hint that these animals were able to control their body temperature, they were hot-blooded animals," said Alexander Kellner, a paleontologist at Brazil's National Museum in Rio.

"This is of great importance to understanding how the pterosaur functioned."

The UV analysis of the fossil showed that the creature had several layers of fibers to control its wings, rather than one as previously thought, suggesting it had more stability and control over its flight than flying animals such as bats.

The pterosaurs, which ranged in size from small up to the largest creatures known to have flown, went extinct about 65 million years ago, around the same time as the mass extinction of dinosaurs.

(Reporting by Stuart Grudgings and Alice Pereira; Editing by Phil Stewart)

http://www.newsdaily.com/stories/tre5745gj-us-china-pterosaur/

Malaria may have come from chimps

Posted 2009/08/04 at 2:17 am EDT

WASHINGTON, Aug. 4, 2009 (Reuters) — Malaria may have jumped to humans from chimpanzees much as AIDS did, U.S. researchers reported on Monday in a study they hope could help in developing a vaccine against the infection.

A chimpanzee sits in his enclosure in Berlin Zoo, June 9, 2009. REUTERS/Fabrizio Bensch

They found evidence the parasite that causes most cases of malaria is a close genetic relative of a parasite found in chimpanzees. Genetic analysis suggests the human parasite is a direct descendant of the chimp parasite, they reported in the Proceedings of the National Academy of Sciences.

The malaria-causing parasite Plasmodium falciparum may have been transmitted to human beings as recently as 10,000 years ago, Francisco Ayala of the University of California Irvine and colleagues said.

"When malaria transferred to humans, it became very severe very quickly," Ayala said in a statement.

"The disease in humans has become resistant to many drugs. It's my hope that our discovery will bring us closer to making a vaccine."

Malaria kills an estimated 1 million people a year, mostly children, according to the World Health Organization. The mosquito-borne parasite causes severe disease in more than 300 million every year.

Ayala's team sampled blood samples from 94 chimpanzees in Cameroon and Ivory Coast to find the apes' version of the parasite.

"The closest known relative of P. falciparum is a chimpanzee parasite, Plasmodium reichenowi," they wrote. They found eight samples of P. reichenowi.

Their genetic testing of the samples showed all known P. falciparum parasites originated from P. reichenowi.

Researchers are trying to make a vaccine against malaria but are having difficulty. Understanding how it became adapted to humans could help in this work.

The finding is the latest to show that some of humanity's worst diseases originated in animals. AIDS came from chimpanzees -- and French researchers reported on Sunday that they found a Cameroonian woman had been infected with an HIV virus that apparently came from gorillas.

Swine flu, H5N1 avian influenza and in fact all influenza viruses are believed to have originated in animals. Other animal-to-human infections include severe acute respiratory syndrome, or SARS, which killed 800 people in 2003-2004, Ebola and Marburg viruses, and plague.

(Editing by Xavier Briand)

http://www.newsdaily.com/stories/tre5725r6-us-malaria-source/

Swine Flu: What Does It Do To Pigs?

ScienceDaily (May 12, 2009) — The effects of H1N1 swine flu have been investigated in a group of piglets. Scientists studied the pathology of the virus, finding that all infected animals showed flu-like symptoms between one and four days after infection and were shedding virus two days after infection.

Roongroje Thanawongnuwech led a team of researchers from Chulalongkorn University, Bangkok, who infected 22-day old pigs with both the H1N1 strain of swine flu and the less dangerous H3N2 subtype.

He said, “The results demonstrated that both swine flu subtypes were able to induce flu-like symptoms and lung lesions in weanling pigs. However the severity of the disease with regard to both gross and microscopic lung lesions was greater in the H1N1-infected pigs”.

All infected pigs developed respiratory symptoms such as nasal discharge, coughing, sneezing and conjunctivitis. Upon pathological examination, lung lesions large enough to be seen by the naked eye were observed.

According to Thanawongnuwech, “These lesions were characterized by dark plum-colored, consolidated areas on lung lobes and were most severe two days after infection, especially in the H1N1-infected pigs, where approximately a third of the lung was covered”.

The course of infection was limited to less than a week and none of the animals died.

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Journal reference:

1. Sreta et al. Pathogenesis of swine influenza virus (Thai isolates) in weanling pigs: an experimental trial. Virology Journal, 2009; 6 (1): 34 DOI: 10.1186/1743-422X-6-34

Adapted from materials provided by BioMed Central.

http://www.sciencedaily.com/releases/2009/05/090511091905.htm

Researchers Describe The 90-year Evolution Of Swine Flu

ScienceDaily (July 5, 2009) — The current H1N1 swine flu strain has genetic roots in an illness that sickened pigs at the 1918 Cedar Rapids Swine Show in Iowa, report infectious disease experts at the University of Pittsburgh Graduate School of Public Health in the New England Journal of Medicine. Their paper, published online June 29 and slated for the July 16 print issue, describes H1N1's nearly century-long and often convoluted journey, which may include the accidental resurrection of an extinct strain.

"At the same time the 1918 flu pandemic was rapidly spreading among humans, pigs were hit with a respiratory illness that closely resembled symptoms seen in people," said senior author Donald S. Burke, M.D., dean, University of Pittsburgh Graduate School of Public Health. "Early experiments confirmed that this 1918 swine virus and a human strain emerged about the same time. Since then, this ancestor virus has re-assorted genetically with other influenza strains at least four times, leading to the emergence of the new 2009 strain, which has retained some similarities to the original virus."

In the paper, Dr. Burke and lead author Shanta M. Zimmer, M.D., assistant professor, University of Pittsburgh School of Medicine, describe the temporary "extinction" of the H1N1 virus from humans in 1957 and its subsequent re-emergence 20 years later. They note a small 230-person outbreak of H1N1 in 1976 among soldiers in Fort Dix, New Jersey that did not extend outside the military base. Then, H1N1 influenza re-emerged in 1977 among people in the former Soviet Union, Hong Kong and northeastern China. Careful study of the genetic origin of the 1977 strain showed that it was not the Fort Dix strain, but, surprisingly, was related closely to a 1950 human strain. Given the genetic similarity of these strains, re-emergence was likely due to an accidental release during laboratory studies of the 1950 strain that had been preserved as a 'freezer' virus, they said.

The authors hypothesize that concerns about the Fort Dix outbreak stimulated a flurry of research on H1N1 viruses in 1976, which led to an accidental release and re-emergence of the previously extinct virus a year later. The re-emerged 1977 H1N1 strain has continued to circulate among humans as seasonal flu for the past 32 years.

Although originally traced to Mexico, the exact physical origins of the 2009 H1N1 pandemic virus are unknown. Because the current strain shares common ancestry with older flu strains, it is possible that portions of the population may have partial immunity to the new pandemic virus.

The authors also go on to explain that the danger posed by a virus isn't based solely on its lethality, but also on its transmissibility, which is the ability to jump from animals to humans and to survive by mutating to adapt to its new human host. H1N1 influenza viruses have demonstrated this ability throughout their history.

"Studying the history of emergence and evolution of flu viruses doesn't provide us with a blueprint for the future, but it does reveal general patterns, and this kind of information is critical if we are to be as prepared as possible," said Dr. Burke.

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Adapted from materials provided by University of Pittsburgh Schools of the Health Sciences, via EurekAlert!, a service of AAAS.

http://www.sciencedaily.com/releases/2009/06/090629200641.htm