Tacaribe Virus in Ticks

Researchers at the University of Florida have found that ticks native to southeastern US carry the Tacaribe virus from the family Arenaviridae.  Previous to this discovery the virus had not been isolated in animals or humans in the US. A recent study recorded that about 10% of the ticks that were captured from northern Central Florida contain the virus.  In most cases isolating a virus from an insect isn’t very notable; however several properties of this viral family make this discovery important.  Firstly, the majority of Arenaviruses that infect humans cause severe hemorrhagic disease particular in South America and sub-Saharan Africa.  Viruses such as Lassa virus and Machupo virus can easily kill those without access to medical care.  Fortunately Tacaribe virus doesn’t cause disease in humans.  Secondly, most Arenaviruses that infect humans are transmitted via rodents and their excrements making an insect intermediate host very interesting.  Katherine Sayler, a scientist at the University of Florida Veterinary School said, “This finding is exciting because it expands the range in which these viruses might be circulating in the environment.” With this increased range, also comes increased risk of exposure and infection. The virus was first isolated in bats in Trinidad in the 1950s.  Despite this finding the researchers believed that bats were not the natural reservoir of this virus.  Further attempts to identify the natural reservoir has been unsuccessful.  Discovering that ticks now harbor the disease gives us more answers but it still doesn’t give us the whole picture. 

-Nalani Wakinekona

References

http://www.news4jax.com/news/uf-researchers-discover-new-virus-in-ticks/30686698

A New Threat to the Cuddly & Endangered

Pandas and tigers: Delectably adorable but tragically endangered.

Endangered animals must overcome many obstacles to avoid extinction. Habitat loss, poaching, reduced genetic diversity -- what else could possibly go wrong?

The answer: Canine distemper virus (CDV)!!! 

Paramyxo, our old friend... We've come to talk of you again.
(The Sound of Distemper)

A CDV outbreak is sweeping Chinese wildlife centers. So far, two giant pandas have succumbed to the disease, and two more infected pandas remain in critical condition. There are also 1,600 pandas in the wild that are at risk for the disease. Despite the panic, giant pandas are not our biggest concern. Pandas have incredible immune systems such that the CDV fatality rate in pandas is 10% compared to the usual 50% in adult dogs.

A study suggest that the extremely endangered Amur tiger (also known as the Siberian tiger) may be the most vulnerable to CDV. They live in small groups of up to 25 tigers. Such a small population could be wiped out by a CDV outbreak. Interestingly, the researchers' proposed solution also involve with population size: Separating groups so that each tiger would live alone would make an outbreak unsustainable.

This ties into major themes in viral eradication. Basic (R0) and effective reproduction rates (R) and population thresholds are crucial in determining the sustainability of an outbreak. For instance, if tigers were alone, then R, the average number of tigers that an infected tiger would infect, would be zero. Therefore, the outbreak would start and end with one tiger.

The math checks out. Unfortunately, the feasibility of this plan does not compute. Do we really want to isolate tigers from each other? Let's not forget that small populations also have increased risk of extinction (a theme from island biogeography!). This CDV outbreak is a reminder of the havoc viruses can wreak upon entire species, and how difficult it can be to contain them.

References

1. http://www.natureworldnews.com/articles/11851/20150112/deadly-virus-threatens-endangered-pandas-tigers-alike.htm
2. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0110811
3. http://bakerinstitute.vet.cornell.edu/animalhealth/page.php?id=1088

-- Tina Ju

YOU can contribute to the flu vaccine conversation!

It is no secret that this year's seasonal flu vaccine missed the mark.  Because of the virus's rampant antigenic variation a new and updated vaccine is required each year.  The months of time required for vaccine manufacture and distribution mean that the vaccine must be chosen far in advance of the flu season itself, so the relevant strains must be predicted based on snapshots of new forms flickering onto the scene at the close of the previous flu season.  Unfortunately, this year that data wasn't enough to enable an accurate prediction so this year's vaccine is not well matched to the circulating flu strain.  I had always assumed that such an important and tricky decision was made by an elite team of experts behind closed doors, in some secret corner of of the Centers for Disease Control and Prevention.  It turns out that is only part of the story.  Of course there are national experts working through this tough challenge each year, but if you--the general public--have an opinion to voice, this team will consider your input!  If you are ready to add your two cents to the vaccine selection discussion, book a ticket to Maryland and mark March 4th in your calendar.  To take advantage of this opportunity share your perspective, all you need to do is send a presentation proposal to the FDA by February 18th.  And make sure you can speak quickly!  Only the hourlong block of 12:40-1:40pm is available for all presenters.  According to the FDA announcement of the event, "interested persons may present data, information, or views, orally or in writing, on issues pending before the committee."

--Laurie


http://www.fda.gov/AdvisoryCommittees/Calendar/ucm427596.htm

Origins of Ebola

The evidence for bats as the reservoir of Ebola, though not definitive, is mounting.  According to a journal article published last week in EMBO Molecular Medicine, insect-eating bats are a possible reservoir for the virus.  While bats have long been suspected as the reservoir of Ebola, insect-eating bats have rarely been suggested as the reservoir; many researchers suspect that fruit-eating bats are the reservoir.  However, fruit-eating bats are not found extensively in the Méliandou region of Guinea - where the current outbreak started.  In contrast, the insect-eating bat, Mops condylurus, is found frequently in this region in hollow trees.  Children in Guinea often target these bats for consumption. Moreover, in the village where the outbreak occurred, the index case - a small boy - was known to play around a big hollow tree known to house many of these bats.  Of course, all the evidence so far has been observational and a lot more research must be done to detect the true reservoir of Ebola. Doing so is easier said than done; while antibodies for Ebola have been isolated in this species of bat, the live virus has never been isolated and cultured from it (or any animal).  Still, such research offers hope that we will soon find the reservoir of Ebola.

http://news.nationalgeographic.com/news/2014/12/141230-ebola-virus-origin-insect-bats-meliandou-reservoir-host/

--Andrew Duong

Measles Vaccine Safety

Anti-vaccine sentiments continue to run high in the United States, particularly in affluent areas around the country. The movement began in 1998, when then-doctor Andrew Wakefield published a study in The Lancet, suggesting that the MMR vaccine was linked to autism.

Twelve years later, the study was retracted, but parents continue to rave about the toxic effects of vaccination. Their concerns are reinforced by pseudo-stars like Jenny McCarthy, who add their voices to the din of misinformation. As a result, groups of parents have elected to forego vaccination for their children, and the country has seen outbreaks of mumps in New York,3 measles in Texas,1 and more recently, measles in California’s Disney Theme parks.2

Nevertheless, researchers from the Kaiser Permanente Vaccine Study Center are combatting fear against vaccines. Earlier this week, they published an article comparing the safety of administering a single MMRV vaccine instead of an MMR and varicella vaccine.

The study was prospective, following 12 to 23 month-old children from 2000 to 2012. Ultimately, the researchers concluded that there was not an increased risk of neurological, immunological, or blood disorders from vaccination.

In agreement with past studies, the researchers observed that fever and seizure can occur seven to ten days after a child is vaccinated with an MMR(V) vaccine. This risk is slightly higher forMMRV vaccines, but the risk remains very small. Less than once case of seizure is expected per 1,000 vaccinations.

Although vaccine design should continue to improve and strides in safety and efficacy are to be made, vaccines are an essential public health initiative that must be readily implemented.

Unless we are willing to welcome measles, sneezles, and things that go mumps in the night back into our lives, it is inconceivable to abandon the use of vaccines.

-Luis Garcia

1. http://www.healthline.com/health-news/children-anti-vaccination-movement-leads-to-disease-outbreaks-120312
2. http://www.people.com/article/measles-outbreak-california-disney-parks
3. http://www.livescience.com/43577-why-rich-educated-parents-avoid-vaccinations.html
4. http://www.sciencedaily.com/releases/2015/01/150106095242.htm

Common Cold is Happier in a Cold Nose

It appears that you should have listened to your grandma when she told you to wear the oversized hat and scarf that she had taken the time to weave for you. Believers of old folk wisdom now have scientific evidence to support the idea that cold weather makes people more susceptible to the common cold. For years, the scientific community knew that rhinoviruses replicate better in the nose than other parts of the body and a recent study suggested the mechanism responsible for this phenomenon. 

A study conducted at the Yale university found a correlation between the temperature in the nose and the strength of the innate immune response against the infection that causes the common cold. The researchers examined rhinoviruses, the most common viral infective agents that cause the common cold. They discovered that the epithelial cells in the airway secrete more RID-I-like receptor (RLR)-dependent interferons and an overall higher antiviral defense response at the temperature of 37 degrees Celsius than at 33 degrees Celsius. This evidence of temperature dependent Interferon induction suggests that the reason why rhinoviruses prefer to live in the nose is that the nose has a temperature from 33 to 35 degrees Celsius, while the lungs have a temperature of 37 degrees Celsius. 

With the seasonal rise in the number of common cold cases, the results of this study are useful. The results suggest that those seeking to protect themselves against the common cold or reduce the symptoms should keep their noses warm. Dr. Iwasaki, the principal investigator of the study, indicated, “You can always stay in warm tropical weather or try to prevent the nasal cavity experiencing very cold air.”

By Mariam

http://www.bbc.com/news/health-30685732

http://www.pnas.org/content/early/2015/01/02/1411030112

Book Review: the Hot Zone by Richard Preston

“Hot (Military Slang.): Lethally Infective in a biological sense.” (Preston 418)

"Hot agent: Extremely lethal virus. Potentially airborne.” (Preston 418)

These two definitions taken from Richard Preston’s the Hot Zone convey the urgent and serious tone which Preston uses to describe his topic: Ebolaviruses and Marburg virus of the Filoviridae family. In his non fiction book, he uses a combination of anecdotes of patients’ experiences and facts about the viruses to recount the history of Ebola viruses and depict a general overview of the Filovirus family. Richard Preston starts the book with an account of Charles Monet’s Marburg infection and subsequent outbreak in 1980. He takes us on the journey that Monet went on to and from Kitum Cave in Mount Elgon, he makes the reader apprehensive about the possibility of transmission to those he is around on the plane, the medical staff at the hospital. He describes the progression of his illness with vivid imagery: “He is becoming an automaton. Tiny spots in the brain are liquefying. The higher functions of consciousness are winking out first, leaving the deeper parts of the brain stem still alive and functioning. It could be said that the who of Charles Monet has already died while the what continues to live.” Furthermore he appeals to the readers’ emotions and stomachs when he describes how Monet’s internal organs fail and he bleeds out from all body parts. 

By starting out with an account of the Marburg illness and not giving the reader the facts about Filoviruses, he builds up the suspense and piques the interest in finding out the details about Filoviruses: their route of transmission, their origins, their level of infectiousness. If the reader had no prior knowledge about Marburg when he started reading the book, he would become a detective alongside the author trying to figure out what this disease is. 

A very thrilling part of the book describes Nancy Jaax, ’s encounter with Ebola. After grabbing the reader’s attention with the story of Charles Monet’s illness and subsequent death, he transitions to Thurmont Maryland 1983 and follows the experience of Major Nancy Jaax, a veterinarian with Ebola. What makes the book more appealing to the mass audience is partly the fact that Preston throws in some details about personal lives of the characters and doesn’t just state the facts of the viruses. He interweaves details about Ebola with descriptions of how Nancy always cooked in the house, gave her children baths, lived in a Victorian house, and was married to another veterinarian. These details make her personable and make the readers more concerned when they read about the fact that when she is working with a dead monkey with Ebola, her glove tear. She has a cut on her hand from making dinner the day before and is exposed to the virus. Fortunately she doesn’t have the virus, but he spends several pages accentuating her fears and her apprehensions. 

He goes on to describe Ebola: its classification, appearance, symptoms, etc. He repeatedly says that the knowledge of the properties of Ebola in the scientific community needs to be substantially improved. He describes the history of the Filoviridae virus family and contemplates the origins of AIDS. He devotes several pages to describing the several Biosafety levels and the dangerous implications of Ebola’s classification as a Biosafety level 4 virus. He describes the Ebola Sudan and Ebola Zaire strains and writes about the discovery of the Reston strain and the involvement of the US Army and Centers for Disease Control in its containment. He writes about the eruption of the Ebola virus in a monkey house near the CDC. 

The book ends on a forbearing tone. In the last pages he indicates the fast mutation rate of the AIDS virus and the lack of vaccines for it. Furthermore he conveys the point that while the AIDS virus was disregarded as a minor concern for a minority population of homosexuals in California when it first appeared, it soon progressed to play a major part in society alarming the medical community. He thus compares AIDS to Ebola, not only because they serve as the “revenge of the rain forest,” but also because they have underdog features. At the time of the novel’s publication, Ebola was being ignored by a large part of the world due to the fact that it had at the time of the novel only infected people in West Africa. He states that "AIDS might not be Nature’s preeminent display of power implying that the readers should anticipate something stronger and more dangerous. After discussing AIDS, he travels to the abandoned monkey house in Reston and concludes the book here: “Ebola had risen in these rooms, flashed its colors, fed, and subsided into the forest. It will be back. 

His book serves not just as an interesting informant of the history of Filoviruses but rather as a call to action to the medical community and society in general to enhance research, create effective treatments, and design better ways to combat Ebola when it gets out of the Kitum Cave or some other secluded place again. 

By Mariam Kyarunts

(also posted on amazon.com )