Saturday, February 28, 2015

New technique in the fight against filoviruses

A team of researchers at the Scripps Research Institute (TSRI) has uncovered a cross-reactive antibody that binds to Marburg virus, an equally lethal cousin of Ebola virus. By growing crystals on the antibody (attached to its viral target) and using x-ray diffraction, the team produced three-dimensional images of the antibody-virus interaction (cool image below). Though the antibody specifically targets Marburg virus, the team believes the antibody to be cross-reactive with related viruses (including Ebola viruses).

This study represents the first time that Marburg's glycoprotein has been seen in its infectious state, and may help unlock novel techniques in the development of therapeutics against Marburg virus and other filoviruses. With the proper engineering, one could hypothetically use the antibody to target and bind Ebola virus and other filoviruses to prevent host cell entry and infection.

Marburg virus (purple) and Ebola virus (blue) interactions with antibodies

-Nick Simon

ZMapp: Coming To A Town Near You

Until recently, ZMapp has only been used as a drug to treat Ebola virus infections in emergency cases, but that may be about to change. The drug is now being tested in patients with Ebola, in a joint effort by the United States and Liberian governments.

In order to qualify for the study, patients must be either (1) adults or children with EBOV infections admitted to Liberian health centers (2) healthcare professionals returning to the United States for treatment against EBOV infection or (3) adults or children infected with EBOV in the U.S. after exposure to an infected individual.

As treatment, patients in the study will receive three doses of ZMapp per day for 3 days. ZMapp is a collection of antibodies that function by targeting surface proteins of the Ebola Virus virion. In order to manufacture the drug, tobacco plants are genetically altered to synthesize the antiviral proteins.

Additionally, patients will receive supportive treatment, such as IV fluids. The control group in study will receive only supportive treatment, which also includes treating additional infections, maintaining blood pressure, and ensuring sufficient oxygen consumption.

Thus far, ZMapp has been administered as emergency treatment to only nine patients, but the study hopes to enroll 100 participants. Consequently, the joint effort by Liberian and American researchers is intended to assess how well ZMapp performs as an antiviral against Ebola.

Although control trials like the one just described appear to be common in assessing novel drug therapies, I question the ethical implications of administering potentially life-saving treatment to only a cohort of candidates. The efficacy of new drugs should be ascertained, but if we are to conduct clinical research with an explicit intent to do no harm, maybe it’s time to remodel clinical drug tests.

How do you withhold potentially life-saving treatment? How do you ensure that the treatment group is safe? I'm not entirely convinced that we're qualified to answer these questions.


Thursday, February 26, 2015

Public Health Challenges in Medical Volunteerism - You Can Haz Ebola?

A physician that traveled to West Africa to help treat patients with Ebola recently commented on media scrutiny since his return to the United States. After arriving in New York in October, Dr. Craig Spencer was diagnosed with an Ebola virus infection. He was treated and eventually recovered, but in the interim, public health officials criticized and questioned the risk he posed to the general public.

According to Spencer, he was named a public health menace by some and a hero by others, to which he responded, “...I am none of those things.”

Spencer went abroad to serve with Doctors Without Borders. He mentioned the challenges of providing medical services abroad, especially in treating such a dangerous virus, but Spencer also expressed the sense of satisfaction he felt from helping infected patients. “No matter how hour of profuse sweating in the suit and the satisfaction I got from treating ill patients washed away my fear and made me feel new again.”

Spencer’s comments raise interesting questions about the role of physician voices in public health campaigns. As Ebola. measles, and other infectious agents continue to pose substantial risks to communities domestically and abroad, it is important for the general public to hear from professionals working most proximally with these diseases.
Subjecting medical practitioners to rebuke from the media and public outcry may make it less likely for them to participate in efforts against infectious disease in developing areas, so it is critical that doctors with past or present experiences contribute to national dialogue about safe and ethical medical volunteerism.


Saturday, February 21, 2015

Dont Wash out that Dirty Mouth

Your mouth is a dirty place.

Your gums are teeming with bacteria—and don’t even get me started on the colonies living between your teeth. Some of these colonies are harmless, but some cause serious disease if they manage to get under the outer tissue layer.

One such bacterium is enterococcus faecalis. Normally it lives in the gastronintesintanl tract, but can occur in the mouth. However, if it gets into your blood stream,  the result can be endocarditis (infection of the heart) or bacteremia (bacteria in the blood stream).
Often, this bacterium causes problems for dentists and their patients—especially during root canals. And infection can be hard to dispose of, especially since the bacteria secretes a sticky protective layer called a biofilm.

A recent study in the journal of Applied and Environmental Microbiology has discovered a helpful phage—or bacteria-targeting virus—that seems to work even better than antibiotics. The phage, called EFDG1, was highly effective in all the situations the researchers tested. It almost completely eliminated the bacteria is both normal culture and ones rife with biofilm.

The coolest part of this? The phage was originally isolated from sewage. It is now being explored as a possible therapy to drastically reduce the rate of E. faecalis infection after dental surgery.      



Floridians Oppose Release of Mutant Mosquitos for Viral Vector Control

A proposal to release genetically-engineered mosquitos into Key Haven, Florida in an effort to reduce mosquito populations and limit the spread of emerging viruses like Chickungunya and Dengue has met with considerable resistance from the public.  The mosquitos are a product of for-profit biotechnology company Oxitec, which has already released 70 million of these modified mosquitos into other communities arround the globe for the same purpose.  The Oxitec mosquitoes contain a gene called OX513A that makes their offspring inviable.  When these Oxitec mosquitos are released into the normal mosquito population, they compete with normal mosquitos to breed with females, “occupying” the female population with offspring that will not survive and thereby reducing the total amount of productive mosquito breeding and limiting the growth of the mosquito population. 
Many residents of Key Haven, a peninsula town of 444 homes, are wary of these genetically-modified insects and the Mosquito Control District has received over 1,600 emails from residents voicing their opposition, in addition to a petition against the mosquito release with over 149,000 signatures.  Although the moquitos are engineered to be a self-limiting population, these residents still feel the choice to release these insects would be dangerously irrevocable and unnecessary.  Currently, the community uses alternative mosquito control strategies such as the distribution of inseciticdes by planes flying overhead.  By contrast, the mutant mosquitos offer a more targeted approach with fewer negative consequences—as well as many benefits—to the human population of Key Haven. 

However, the self-limiting nature of these bugs means they do not represent a permanent vector control solution.  When the mutant mosquitos die off, the normal mosquito population could quickly recover its former population size, leaving the Key Haven community in the same place it began.  In order to maintain a reduced moquito population continued release of the Oxitec mosquitoes would be necessary.  The Oxitec company therefore stands to make a considerable profit if the Florida Keys Mosquito Control District moves forward with this strategy.
Read the full article here:

Chikungunya Or Arthritis?

Chikungunya is an ARBO virus that is known to cause fever, rash, and joint pain and swelling. Consequently, a growing number of physicians have encountered difficulties distinguishing between the virus and rheumatoid arthritis.

Interestingly, research published in Arthritis and Rheumatology recently indicated that blood tests from chikungunya-infected patients and patients suffering from rheumatoid arthritis yield similar results. The study also argued that chikungunya-associated joint pain lasts 12 - 15 months for the majority of patients, but that the pain can persist in patients for up to 3 years. Convoluted blood tests make it additionally difficult for clinicians to discern between the two conditions.

This study was limited in terms of sample size, however, for only ten individuals were included in the study, Nevertheless, 8/10 of patients with viral infection also met the American College of Rheumatology’s criteria for arthritis, providing some evidence that further investigation may be warranted.

Originally discovered in Africa about 60 years ago, chikungunya has been increasing in prevalence around the globe ever since. The virus has spread to the Caribbean and Central and South America. Moreover, the CDC estimated that approximately 2,000 Americans were infected with the virus after traveling to other countries in 2014, and the state of Florida saw an interesting increase in cases of chikungunya, suggesting that mosquitoes in the area may be transmitting the virus.

Ultimately, this research is most salient for practicing physicians, who should take careful medical histories when meeting patients. Taking a detailed history may uncover risk factors for chikungunya that could help distinguish the disease.


Friday, February 20, 2015

Okay, is Ebola Airborne or Not?

Scientists and public health officials alike have argued over the routes of transmission of Ebola virus for a while, especially since the start of the recent outbreak in West Africa. While officially Ebola is considered to be spread only via bodily fluids, there remains some debate. Many are convinced that it can in fact be spread through respiratory droplets as well. 

While this possibility is a scary one, it’s one that is “very likely”, according to a team of researchers led by Michael Osterholm, an epidemiologist at the University of Minnesota. Blood, feces, and vomit are undeniably the primary routes of virus transmission; however, Dr. Osterholm maintains that tiny droplets of virus containing fluid hang in the air and are occasionally breathed in by others. This, he argues, provides an unrecognized method of transmission of the Ebola virus. Evidence the team uses to draw this conclusion includes Ebola virus found on the outside of face masks worn by health workers caring for Ebola victims. In addition, as described in Richard Preston’s The Hot Zone, Ebola virus has been passed between monkeys through a respiratory route. 

While this evidence in no way proves that the Ebola virus strain responsible for this massive outbreak can pass between humans by a respiratory route, it should serve to keep the door of the public and more importantly of the scientific community open to this possibility. Hopefully more rigorous research will continue to be done over the course of this outbreak, so we can better understand the nature of this disease and more effectively manage it in the future.

-        Eddie