Ebola highlights growing global virus threat

Mariette Le Roux and Elisabeth Zingg in Medical Press:  Like the Spanish flu, polio, AIDS, and SARS before it, Ebola has erupted from seemingly nowhere to claim lives and sow fear of a catastrophic global outbreak.

While experts say the current epidemic is unlikely to become global, they warn of ever more viral outbreaks in future as increasing numbers of globetrotters are exposed to strange new pathogens that they take home to spread in crowded cities. "New viral diseases are on the rise as populations become more dense and mobile," said Arnaud Fontanet, head of epidemiology at France's Insitut Pasteur.

Add to this habitat loss from deforestation and climate change forcing pathogen-carrying animals closer to human settlements, and you have all the ingredients for brewing potent pandemics. "Outbreaks do seem to be getting more frequent," University of Nottingham molecular virology professor Jonathan Ball told AFP.

"Are we heading for the big one? It wouldn't be a huge surprise if there's another (major pandemic) waiting to happen. What that virus will be or when it will happen is tricky to judge. All we can do is monitor and be prepared."

Perhaps more than any other in recent history, the 2003 outbreak of SARS—a deadly new respiratory disease—raised the spectre of the kind of global devastation caused by the 1918-20 Spanish flu that wiped out 50-100 million people. SARS claimed 800 lives, mainly in Asia, but not before infecting people in nearly 40 countries within weeks and causing a panic that saw flights cancelled, schools closed and sales of surgical masks spike....

A box of surgical masks, shot by Tokumeigakarinoaoshima, Wikimedia Commons, under the Creative Commons 0.0 license

Ebola outbreak death toll in West Africa rises to 135

Voice of America News: The World Health Organization says the death toll from the Ebola outbreak in West Africa has risen to at least 135. In a Thursday statement the WHO says Guinea's health ministry had reported a total of 122 deaths, while 13 deaths had been reported by Liberian health officials.

The WHO says officials are investigating more than 200 suspected or confirmed cases of the virus in Guinea, Liberia and Sierra Leone. Six suspected cases in Mali tested negative and no new suspected cases have been reported.

This is the first major outbreak of Ebola in West Africa. Authorities say it began in a forested southeastern region of Guinea in February.

The Ebola virus is spread by contact with bodily fluids. It causes symptoms that include vomiting, unstoppable bleeding and organ failure....

A CDC image of the Ebola virus

India develops cheap rotavirus vaccine

T.V. Padma in SciDev.net: An Indian vaccine against rotavirus — the leading cause of diarrhoea-related deaths in most developing countries — promises cheap home-grown protection while adding to the global basket of rotavirus vaccines, an international team announced.

Severe diarrhoea caused by rotavirus claims the lives of 453,000 under-five children worldwide each year. India tops the list, contributing to 22 per cent of the deaths or an estimated 100,000-163,000 each year. Half of India’s rotavirus-related diarrhoeal deaths are of less-than-a-year old infants.

The two internationally licensed oral rotavirus vaccines, GlaxoSmith Kline (GSK)’s Rotatrix and Merck’s Rotatec, are priced at US$ 40 per dose, but provided at US$ 2 per dose in poor countries under an arrangement with the Global Alliance for Vaccine Initiative (GAVI).

This week (14 May), scientists announced in New Delhi the results of third phase of clinical trials — involving 6,799 infants in three Indian states — of Rotavac, an oral vaccine based on a strain circulating in India and developed under an Indo-US partnership.

Rotavac reduced severe rotavirus-related diarrhoea cases by 56 per cent in infants under-one year, with protection continuing into the second year, K Vijayargahavan, secretary, Department of Biotechnology, told an international symposium....

Computer reconstruction of a rotavirus particle, by Dr Graham Beards, Wikimedia Commons, under the Creative Commons Attribution 3.0 Unported license

Saudi Arabia sees more SARS-like virus cases

Al-Jazeerah.com: Saudi Arabia has confirmed four new cases of the SARS-like coronavirus in its Eastern Province, state media has reported, citing the health ministry.

The health ministry said that one of the four new cases had been treated and the patient had been released from hospital, while the three other new cases were still being treated, the Saudi Press Agency reported on Monday. 

On Sunday, Saudi Arabia said it had a total of 24 confirmed cases since the disease was identified last year, of whom 15 had died.

World Health Organisation officials visiting Saudi Arabia to consult with the authorities on the outbreak said on Sunday it seemed likely the new virus could be passed between humans, but only after prolonged, close contact....

The Gulf of Suez from orbit, via NASA

Viruses from sewage contaminate deep well water

Janet Pelley in Chemical & Engineering News: Scientists once thought that pathogens could not reach drinking water wells sunk into deep, protected groundwater aquifers. Nevertheless, over the past decade, researchers have identified diarrhea-causing viruses at a handful of deep bedrock well sites in the U.S. and Europe. Now, researchers in Madison, Wis., report where these pathogenic viruses may have originated. The viruses appear to seep from sewer pipes and then swiftly penetrate drinking water wells....

The U.S. Environmental Protection Agency does not regulate the presence of viruses in drinking water, so many public water systems do not routinely test for them. In a 2007 study, a team of researchers, including Mark Borchardt, a microbiologist with the U.S. Department of Agriculture, and Kenneth Bradbury, a hydrogeologist at the University of Wisconsin-Extension, in Madison, investigated the integrity of aquifers confined beneath a thick layer of clay or ... Groundwater models predicted that surface contaminants would require tens to hundreds of years to reach wells in these aquifers, which typically sit more than 700 feet underground. Even if pathogens did find their way to the groundwater, they should be dead after that amount of time. “But we were shocked to find human-specific viruses—some of which were still infectious—in every well we sampled in Madison,” Bradbury says.

This group and others in the field suspected that leaking sewer pipes were the source, so the scientists launched a sampling program to determine how the pathogens got into the wells. Every two to four weeks, the team sampled sewage at the city’s waste treatment plant and water pumped from six wells prior to any disinfection. They identified viruses and measured their concentrations in the samples using real-time quantitative polymerase chain reaction.

Viruses appear and disappear in the human population on a monthly cycle, which allowed the researchers to track their presence in sewage and well water, Borchardt says. After the team detected viruses in the sewage, the same viruses appeared simultaneously in all six wells a few weeks later, usually after rain or snowfall melt. The scientists could correlate when the pathogens popped up in the well water with their appearance in the sewage system.

What’s more, the scientists cultured the viruses from the wells and showed that they were still infectious. Virus concentrations similar to those found in the study are sufficient to cause vomiting and diarrhea, Borchardt says. However, “because Madison chlorinates its water, no one has become sick,” Bradbury adds....

A surface aerator at a water treatment plant, shot by Trlabarge, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

March of the pathogens: Parasite metabolism can foretell disease ranges under climate change

Morgan Kelly in News at Princeton: Knowing the temperatures that viruses, bacteria, worms and all other parasites need to grow and survive could help determine the future range of infectious diseases under climate change, according to new research.

Princeton University researchers developed a model that can identify the prospects for nearly any disease-causing parasite as the Earth grows warmer, even if little is known about the organism. Their method calculates how the projected temperature change for an area would alter the creature's metabolism and life cycle, the researchers report in the journal Ecology Letters.

Lead author Péter Molnár, a Princeton postdoctoral researcher of ecology and evolutionary biology, explained that the technique is an all-inclusive complement to current methods of predicting how climate change will affect disease, which call for a detailed knowledge of the environmental factors a specific parasite needs to thrive. But for many parasites, that information doesn't exist.

The more general Princeton model is based on the metabolic theory of ecology. Under this premise, all biological organisms need a balance between body size and body temperature to maintain the metabolism that keeps their organs functioning. Like any cold-blooded creature, disease-causing parasites rely on external temperatures for this balance. Scientists with knowledge of a parasite's body size and life cycle could use the Princeton metabolic model to predict how the organism would fare in altered climates.

"Our framework is applicable to pretty much any parasite, and utilizes established metabolic patterns shown to hold across a wide variety of species," Molnár said. "It would be impossible to ever gather enough data to develop a separate climate-change model for each existing and emerging disease in humans, wildlife and livestock," Molnár said. "With our physiological approach, many of the parameters for a specific pathogen can be predicted based on what is known about metabolic processes in all parasites, so that the model remains applicable to new and less-studied species as well."...

A cameo by the Marburg virus, image from the CDC

A war without end - with earth’s carbon cycle held in the balance

Oregon State University: The greatest battle in Earth’s history has been going on for hundreds of millions of years - it isn’t over yet - and until now no one knew it existed, scientists reported today in the journal Nature.

In one corner is SAR11, a bacterium that’s the most abundant organism in the oceans, survives where most other cells would die and plays a major role in the planet’s carbon cycle. It had been theorized that SAR11 was so small and widespread that it must be invulnerable to attack.

In the other corner, and so strange-looking that scientists previously didn’t even recognize what they were, are “Pelagiphages,” viruses now known to infect SAR11 and routinely kill millions of these cells every second. And how this fight turns out is of more than casual interest, because SAR11 has a huge effect on the amount of carbon dioxide that enters the atmosphere, and the overall biology of the oceans.

“There’s a war going on in our oceans, a huge war, and we never even saw it,” said Stephen Giovannoni, a professor of microbiology at Oregon State University. “This is an important piece of the puzzle in how carbon is stored or released in the sea.”

Researchers from OSU, the University of Arizona and other institutions today outlined the discovery of this ongoing conflict, and its implications for the biology and function of ocean processes. The findings disprove the theory that SAR11 cells are immune to viral predation, researchers said.

“In general, every living cell is vulnerable to viral infection,” said Giovannoni, who first discovered SAR11 in 1990. “What has been so puzzling about SAR11 was its sheer abundance; there was simply so much of it that some scientists believed it must not get attacked by viruses.” What the new research shows, Giovannoni said, is that SAR11 is competitive, good at scavenging organic carbon, and effective at changing to avoid infection. Because of that, it thrives and persists in abundance even though it’s constantly being killed by the new viruses that have been discovered....

A SAR-11 bacterium infected with the pelagiphage virus. Photo courtesy of the University of Oregon