Highlights include Saudi Arabia’s hajj travel restrictions, zoonotic adenoviruses, PEDv, studying the 1918 pandemic, and plague in people you know. Happy Friday!
Saudi Arabian officials, responding to fears over hajj contributing to MERS potential spread, have significantly cut the number of pilgrims allowed to perform the annual pilgrimage to Mecca. Numbers of pilgrims from within Saudi Arabia have been cut by half, and those travelling to Mecca from other countries by one fifth. Officials were quick to stress that the decision was based on “exceptional” circumstances, and may be revised as MERS’ spread is tracked. The decision is an interesting one, given that the WHO’s specially convened MERS committee just last week decided against travel restrictions.
Economic Times – “Fears of an outbreak of the deadly MERS virus in Saudi Arabia and construction in the holy city of Mecca have forced cuts in the numbers of pilgrims permitted to perform this year’s hajj. Millions of Muslims during the annual pilgrimage head to Mecca and Medina, Islam’s two holiest sites, providing a possible means for MERS to spread around the globe as pilgrims who may become infected return to their home countries.”
Most of the world’s deadliest viruses are zoonotic (ebola, anyone?) When a new virus is determined to spread from animals to humans, it’s therefore not surprising, but it’s often troubling, as humans often have little to no immunity to such bugs. The ongoing outbreaks of H7N9 and MERS are both recent examples. Now, researchers at the University of San Francisco have determined that a novel adenovirus – identified just four years ago – may be able to cause disease in humans. In a study involving adenovirus C, the researchers were able to trace the virus’ spread from an enclosed Californian baboon colony to the human staff members caring for them.
UCSF – “‘This study raises more concerns about the potential of unknown viruses to spread from animals to humans,’ said Chiu, who is an assistant professor of medicine at UCSF. ‘We still don’t understand the full extent of viruses that exist in the world and their potential to cause outbreaks in human populations.’ Last year, Chiu and colleagues also identified another new adenovirus, named simian adenovirus C, which sickened four of nine captive baboons and killed two of them at a primate facility in 1997. Several staff members at the facility also complained of upper respiratory symptoms at the time of the outbreak. Re-examining the samples many years later, Chiu and his colleagues found antibodies targeted to simian adenovirus C in the human samples.”
The porcine epidemic diarrhea virus (PEDv) continues to rage in the United States, having now spread to 14 states, including outliers like North Carolina. With the virus’s fatality rates occasionally approaching 100% in piglets, its spread has USDA and the US pork industry both (understandably) very nervous. The virus’ source in the United States remain unknown, and efforts to sequence it have been hampered by a couple things. First, it is notoriously difficult to culture – unsurprisingly, pig viruses tend to grow best in pigs. Second, the restrictions the US had in place to prevent the virus entering the US in the first place are making acquisition of the right lab materials to culture it difficult. With the virus’ apparent preference for cooler temperatures, and Autumn approaching, scientists are racing to determine the source before the outbreak spreads further.
Scientific American – “‘How this virus got here, that’s the million-dollar question,’ says James Collins, director of the Veterinary Diagnostic Laboratory at the University of Minnesota in St Paul. The pathogen, a type of coronavirus called porcine epidemic diarrhea virus (PEDV), was first identified in the United Kingdom in 1971, and it caused mass epidemics in Europe in the 1970s and 1980s…The virus can spread quickly by a fecal–oral route and infect entire herds. And although adult pigs typically recover, PEDV can kill 80–100% of the piglets it infects. The virus poses no health threat to humans. The US Department of Agriculture (USDA) had tried to keep PEDV and other diseases out of the country by restricting imports of pigs and pork products from certain nations, such as China. But on 10 May, the Veterinary Diagnostic Laboratory at Iowa State University in Ames confirmed that PEDV had infected pigs in Iowa, the leading producer of US pork.”
After using mathematical models to analyze the 20th century’s worst pandemics, the 1918 Spanish flu pandemic. Researchers have developed three key factors which exacerbated the pandemic’s impact – school openings and closing, temperature fluctuations, and human behavioral changes.
Science Daily – “Dr He and the researchers further applied this model to the reported influenza mortality during the 1918 pandemic in 334 British administrative units and estimate the epidemiological parameters. They have used information criteria to evaluate how well these three factors explain the observed patterns of mortality. The results indicate that all three factors are important, but behavioural responses had the largest effect.”
It’s easy to believe that the bacteria and viruses we write about exist only in distance countries or highly secure labs. As the above blog piece illustrates, sometimes all it takes is a vacation to New Mexico. The piece also discusses the importance of science’s ugly stepchild – basic research.
Motherboard (VICE) – “Despite very low incidence and the availability of treatment with modern antibiotics, the plague is still a very deadly illness whose prognosis becomes worse by the minute when it strikes. This technique is useful because it provides a quick way of, at the very least, ruling out the illness, which is so often overlooked. Importantly, the researchers note that their technique would not have been possible without previous basic research, which many consider a lesser priority than corporate-sponsored applied research.”
(image courtesy of Al-Hijr)