Pandora Report 3.1.15

My apologies for no update last week, I had to make an unexpected, emergency, work-related trip to Dulles Airport, my old stomping grounds. But everything is under control and we’re back at it, covering stories from the past two weeks. Fittingly, we start off with airport screening, and also cover the Black Death, chemical weapons in Libya, Ebola, and other stories you may have missed.

Have a great week and stay safe in the weather out there!

Airport Screening for Viruses Misses Half of Infected Travelers

A team led by UCLA researchers has found that airport screening—for viruses like H1N1 and Ebola—misses at least half of infected travelers. The team found that no more than 25% of passengers answered honestly about their exposure to influenza in 2009 and that some may have been able to hide symptoms by taking over-the-counter drugs like acetaminophen. Timing of the screening may impact detection ability, too.

Science 2.0—“‘We found that for diseases with a long incubation period, such as Marburg and Ebola, taking passenger’s temperature to test for fever is particularly ineffective at the start of the epidemic but does pick up more cases as the epidemic stabilizes,” said Katelyn Gostic, a lead author of the study and a UCLA doctoral student in the laboratory of Professor James Lloyd-Smith. “With diseases such as swine flu, which take a shorter time to incubate, fever screening is the most effective method throughout an epidemic.’”

Plague Pandemic May Have Been Driven by Climate, Not Rats

Rats may have been incorrectly receiving centuries of blame for European plague, or Black Death. According to Nils Stenseth, of the University of Oslo, the introduction, and re-introduction, of the disease to Europe may have been caused by Asian climate events. Additionally, black rats where rare in Northern Europe, so the likely rodent culprit may have actually been gerbils. Moreover, the plague is not naturally found in Europe, but it is endemic in Asia in the rodents that live there. However, when the climate becomes warmer and wetter, rodent numbers drop and the fleas seek out alternative hosts, like domestic animals and humans.

Smithsonian—“The scientists will need more data to prove that Asian climate was responsible for all the reintroductions of plague to Europe. For instance, analysis of plague DNA from European victims who died at different time periods could strengthen the link between climate and outbreaks. “If our theory of climate-driven successive reintroductions is correct, we would expect to find great genetic bacterial variation between plague victims across time,” Stenseth explains. If the bacteria had instead come from a single introduction, there would be less genetic variation in the pathogen’s DNA, even when taken from victims from different times and locations.”

ISIS Chemical Weapons Libya: Military Warns Islamic State Might Have Mustard Gas, Sarin

Islamic State fighters in Libya have allegedly seized large amounts of chemical weapons including mustard gas and Sarin that reportedly belonged to the regime of Moammar Gadhafi. Last year, though, Libyan officials said they destroyed the last known stockpile from Gadhafi’s regime.

International Business Times—“The weapons are likely 10 years old and in a degraded state, but remain dangerous, former British Army officer Hamish de Bretton-Gordon told The Daily Mail Sunday. “While we don’t know how much IS has acquired, and though the Libyan Sarin dates back to the Gadhafi era, it would still have a toxicity and pose a danger,” he said. “Libya is virtually Europe and so the fear factor from a European perspective is huge. I should think the security forces will be watching this situation very closely.’”

This Week in Ebola

It’s been awhile since an Ebola update, but there was some good news worthy of coverage as schools re-opened in Liberia on February 16, as a sign that life is starting to return to normal. Countries are still keeping an eye out for the virus, including, inexplicably, North Korea, who has banned foreign runners from their April marathon (yes, that is actually a thing!) A piece appeared in the Journal of the American Society of Microbiology that indicated it is “very likely that at least some degree of Ebola virus transmission currently occurs via infectious aerosols generated from the gastrointestinal tract, the respiratory tract, or medical procedures.” However, there is some good news including a new product, similar to hand sanitizer, that can kill bacteria and viruses within 15 second of application and can work for up to six hours and a rapid diagnostic test for both Ebola and Dengue. Lastly, it wouldn’t be an Ebola update without a questionable article—this one is about a Baltimore wedding gown designer who went to New York Fashion with an Ebola suit. Sigh.

Stories You May Have Missed

 

Image Credit: Micah Sittig

Bubonic Plague: An Airborne Toxic Event

by Alena M. James

Yersinia pestisis a gram negative, bacillus shaped bacteria that prefers to reside in an environment lacking oxygen (anaerobic). It is typically an organism that uses the process of fermentation to break down complex organic molecules to metabolize.  However, the organism is commonly referred to as being a facultative anaerobe, because it can live in the presence of oxygen and undergo respiration to generate energy for its cell. Its facultative capability is one reasons the organism can induce infection in highly oxygenated lung tissue.

This organism, primarily a zoonotic pathogen, has been held responsible for causing the bubonic form of plague responsible for the Black Death, the 14th century event that lead to the death of millions of Europeans. For years, the cause of the Black Death Plague pandemic has been linked to fleas. In much of Europe at this time, unsanitary living conditions provided the perfect breeding grounds for flea infested rats to flourish; while the fleas served as the perfect arthropod vector for Y. pestis to flourish.

The route of transmission of Y.pestis, from fleas to humans, was thought to occur via the urban cycle—when an urban rat becomes infected with fleas from a wild animal. Crowding in cities, poor hygiene, and unsanitary living conditions attracts large rat populations to the area. When a flea carrying Y.pestis bites a rat, the rat becomes sick and dies. No longer able to parasitize the rat, the flea moves from the rat to a new host. In crowded cities, the fleas from the dead rat will jump to humans to feed. When the flea bites the human it releases Y. pestis into the human’s cardiovascular system. Once in the cardiovascular system, the bacterial organism makes its way to the lymph nodes.  There it replicates and spreads throughout the body causing septicemia. As Y. pestis proliferates within the lymph nodes it also forms hemorrhagic necrosis throughout the body.  Painful swelling arises and the definitive painful symptom, the bubo,appears.  After infection, a patient develops a high fever and the organism can target specific organs of the body like the lungs, liver, and spleen. Without treatment, a patient has a 75% mortality rate.


Last week, British scientists performed comparative DNA analysis on bacterial samples collected from 25 excavated skeletons found in the Clerkenwell area of London. These remains dating back to the 14th century contained samples of Yersinia pestis, the bacteria responsible for the Black Death. In an attempt to evaluate the virulent nature of the pathogen, the Y. pestis DNA collected from these remains were compared to DNA from the Y. pestis responsible for the deaths of more than 30 people in Madagascar back in December 2013. Researchers concluded that the DNA of both organisms revealed a high percentage of similarity and that the pathogenic nature of the 14th century Y. pestis is no more powerful than the Y.pestsis responsible for the Madagascar killings.

After considering this information and examining the plausible death of the skeletons, scientists believe that the fast-acting killing capabilities of Y.pestis are only likely to take place through airborne transmission. This conclusion undermines the urban cycle transmission method and suggests that the Black Death was mostly caused by pneumonic plague and not bubonic. British scientists are determined to examine more modern cases to confirm this new hypothesis. If confirmed, we may see pneumonic plague identified as the causative agent for the 14th century plague pandemic thus altering our historical account of the Black Death.

For British scientists, the transmission of Y. pestsis through respiratory droplets is a much more likely scenario for achieving rapid kills versus the urban cycle transmission method. Bubonic plague is not infectious and there is no human to human transmission from the buboes that form.  However, pneumonic plague can be caused by bubonic plague if the Y. pestis pathogen makes its way via the lymph nodes to the lungs inducing infection. While in the lungs, the organisms are caught in respiratory droplets and are then disseminated into the air when an infected person sneezes or coughs. This quickly makes the host very infectious and a threat to those not yet infected.  The mortality rate for patients suffering from pneumonic plaque without treatment is 100%.

 

Image Credit: crossrail.co.uk