Tuesday, September 30, 2014

Experimental Evidence Suggests Camels are the Reservoir for MERS

If you have travelled in the past six months and stood in the security line of a main airport, chances are that you saw a sign warning against Middle East Respiratory Symptom (MERS).  MERS is a viral disease caused by a coronavirus called MERS-CoV.  Most individuals that become infected will experience fever, cough, and shortness of breath before developing a severe respiratory illness if interventions or treatment are not provided.  About 30% of people who are infected will die.  MERS first came onto the global health scene when the cases were identified in Saudi Arabia in the spring of 2012 by the country’s Ministry of Health.  Cases were later reported in Jordan, the United Arab Emirates, Oman, and Yemen.  In May of 2012, the Center for Disease Control and Prevention confirmed two cases, in Indiana and Florida, from healthcare workers who had been in Saudi Arabia. Health officials were initially worried for several reasons.  Firstly, there were
several aspects of the virus that were unknown including but not limited to transmission, associated illnesses, and origin.  Secondly, there was also a major concern about the annual pilgrimage and how it would influence the spread and transmission of the virus.  But it is September of 2014, and about 2 years have passed since the first cases of MERS were confirmed.  So why is this news hot and new?

One important question that all viruses must answer is: what is the host or the reservoir of the virus?  In virology the reservoir is the animal that carries a particular virus without suffering from any illnesses or symptoms.  A possible reservoir of MERS-CoV is the dromedary camel.  The camel was the first suspect because large numbers of camels in the Middle East have tested positive for the virus.  In spite of these findings there has never been strong evidence to say that the camel is the one and only reservoir or host of this virus until recently.  A study published in the Journal of Emerging Infectious Disease in 2014 has provided experimental evidence supporting this theory.  In short infected camels can shed large amounts of the virus via nasal secretions from their upper respiratory tract. Researchers theorize that by vaccinating camels, you can substantially reduce the risk of transmission to camels and other people.  Unfortunately there is no vaccine to protect against MERS, but with this new information the National Institute of Allergy and Infectious Diseases (NIAID) has increased its research to develop possible vaccines for both camels and humans. 

-Nalani Wakinekona




EV-D68 Outbreak Heralds the End of Summer

If you were a schoolchild with asthma, your parents might have thought twice about sending you off to resume classes at the end of this past summer.   A recent outbreak of human enterovirus D68 (EV-D68) has many schools on alert and parents have been advised to keep sick children at home, lest they risk infecting classmates.  According to the Centers for Disease Control’s (CDC) Morbidity and Mortality Weekly Report published September 12th of this year, the first area of the country to note an increase in severe respiratory illnesses that were ultimately attributed to EV-D68 was Children's Mercy Hospital in Kansas City, Missouri.  Since these cases in early August, the virus has been laboratory confirmed to be present in 40 states and the District of Columbia as of September 29th.   A total of 443 individuals have been affected and there have been no fatalities.  There is no vaccine or targeted cure for EV-D68 at present.

States with Cases of EV-D68 as of September 29th, 2014

Cases in the current outbreak have appeared primarily among children with asthma or a history of wheezing.  The high incidence of the virus among children is unsurprising.  Enteroviruses are common---causing between 10 and 15 million infections annually in the United States alone---and most adults have developed adaptive immune defenses against them through previous exposure.  Infants, children and teens, however, often have not been previously exposed to the virus and thus represent a particularly vulnerable population.  In part, the frequent occurrence of enterovirus infections is attributable to the diversity of ways the virus can spread, including through physical contact with infected individuals, contact with fomites (objects infected individuals have touched that now harbor the virus), and drinking contaminated water.

Symptoms of infection are often relatively mild (runny nose, sneezing, coughing, fever, aches, etc.) but can sometimes be so severe as to require hospitalization.  Though a typically rare occurrence, enterovirus infections have been associated with paralysis.  It is instances of paralysis, especially in Colorado, that have prompted worry regarding the current outbreak.

Image courtesy of CNN.

To learn more about cases of EV-D68 in your region and about the virus itself, visit the CDC website here: http://www.cdc.gov/non-polio-enterovirus/outbreaks/EV-D68-outbreaks.html

--Laurie Rumker

Sunday, September 28, 2014

Aedes aegypti Mosquitos Found in Fresno. So far, they've tested negative for the deadly viruses they transmit

Hello everyone!

In summer 2013, I traveled to the Peruvian Amazon to study mosquito ecology. Somewhat ironically, I got sick with dengue (or possible chikungunyua, the diagnosis was never conclusive). Seeing that these mosquitos are spreading north is a bit unsettling for someone who knows personally what the viruses they carry are capable of! Dengue and chikungunya are mosquito-borne viruses that cause rashes, fever (sometimes hemorrhagic in the case of dengue), bone/muscle pain among numerous symptoms. These viruses can be deadly if the patient doesn't get proper medical attention!

With the ebola epidemic ravaging West Africa, it’s easy to forget that we in the United States may not be safe from outbreaks either. Last week, the mosquito Aedes aegypti was found in Fresno when distric health workers placed 120 mosquito traps throughout the city.

Aedes aegypti, adult, Pialoux et al 2007

When they checked the traps, they found the Aedes larvae. A. aegypti is thought to have originated from Africa, although it has spread throughout the tropics.

Fresno isn’t that far from us! (Google Maps)

Why are these mosquitos interesting? They are known to transmit several deadly viral diseases that may soon spread from the tropics: yellow fever, dengue fever and chikungunya. Infections from these viruses can cause fever, severe headaches and even death in extreme cases. None of the mosquitos the health department found tested positive for any of these viruses, but should one of the mosquitos bite a person who traveled to a region with endemic dengue, chikungunya or yellow fever. These viruses reproduce in the guts of mosquitos, as well as in human cells. When a mosquito bites an infected human, it can contract the virus and transmit it to its next victim. Our warming, increasingly interconnected world is allowing these mosquitos, and possibly the viruses they transmit, to spread to higher latitudes. 





Google Maps

--by Joe Getsy '15