Friday, November 17, 2017

CDC recommends that Shingrix replaces Zostavax

Weeks ago, a blog post reported that the FDA had recently approved a new vaccine for Shingles. Now here is a post comparing the new vaccine, Shingrix, to Zostavax, the vaccine that we have been using. Shingrix is to be more effective than Zostavax, which only prevents about half the shingles cases in adults over the age of 60. Shingles affects those older than the age of 60 more severely than those younger and, 1 in 3 Americans will develop this disease caused by varicella zoster virus or herpesviridae. Shingles is caused when the body is reactivated with varicella zoster virus.

The CDC recommends that Shingrix replaces Zostavax. Zostavax is a live, attenuated vaccine which Shingrix is an inactivated, sub unit vaccine that uses an essential subunit of the virus, not the entire virus, to introduce to the body. Shingrix is 97% effective against Shingles for those ages 50 to 69 and 91% effective for those 70 and older. This is a great change from the studies that showed that Shingles only has a 51% effectiveness. However, both vaccines do wain over time in effectiveness but Zostavax effectiveness over time is 15% versus Zostavax’s 25%.

Once CDC directors endorse the committee’s recommendation we can expect to see Medicare and Medicaid covering these vaccines. By early 2018, Shingrix should be readily available for use in the United States.

Jessica Ngo


Thursday, November 16, 2017

A Mother’s Dangerous Kiss

This 3 year old had a rough week recently. Having been feeling angry and irritable all week, the little girl developed little bumps on the lower lid of her eye and next to the eye. During this time, Amber Bard, a third-year medical student at Michigan State, and aunt of the three year old turned to the computer to see what the cause was. Using a database called VisualDx, she crossed out conjunctivitis, sty, and other eye diseases. When the girl’s mother mentioned that she had happened to have a cold sore on her lip earlier the month, Bard narrowed it down to herpes. Now, the eye is quite an unusual place for the herpes virus to infect, but it can infect the eye and cause herpes keratitis, which can cause permanent damage to the eye such as blindness.

The three-year-old was taken to the pediatrician, who told her mother that it was unlikely herpes virus, but a swab was done and sent in for a culture. Everything seemed fine after that but then the little girl’s left eyelid began to droop and light seemed to hurt her eye. Monday morning, the pediatrician called to alert the mom that it was indeed herpes virus. The girl was immediately started with acyclovir antiviral. They eye healed but a few months later two blisters appeared. Poor child had to go through the discomfort and pain again. Luckily she was treated with antivirals and no eye damage resulted from all this.

More about this Type 1 herpes virus: It is very contagious and transmitted through skin contact. The virus attacks the nerves of the skin, resulting in painful blisters or lesions. When the lesion heals, the virus travels up the nerve to the spine or brain, lying dormant to be awaken, travel down the nerve to the skin, and cause lesions appear again.  

Who knew a mother’s kiss could be so dangerous?
                                                                                              -Jessica Ngo                   

Tuesday, November 14, 2017

Ancient Viral DNA Creates Unknown Protein

Viral DNA makes up about 8% of the human genome. And yet, there is still much of it that is left unexplained and mysterious. A recent study identified an unknown protein, called Hemo, in the blood of a mother that appears to be coded for in ancient viral DNA from the fetus and placenta. Scientists are referring to the viral infection that may have caused the creation of this protein "endogenous retroviruses". Retroviruses have the potential to be passed down through generations and can essentially hide within a host. A this point, they are identified as endogenous retroviruses. They can infect many cells and even after this ability is impaired, they can sometimes continue to make proteins and reproduce. Because of this, they have the potential to replicate many times after just one infection so that they can have hundreds of copies in the host's DNA.

Endogenous retroviruses have been found to be present in our ancestors about 450 million years ago. Dr. Odile Heidmann was able to identify the protein Hemo in viral DNA. This very protein was also identified in primates and has supposedly remained unchanged for many thousands of years. Dr. Heidmann explains that this protein "isn't simply a relic" because it is found in many different species over time. It likely has an important role that we simply don't understand currently.

Hemo is produced within the placenta and could potentially act as a communication between the fetus and mother so that the mother's immune system recognizes the fetus as non-foreign. It also may be involved in creating important tissues. From a viral standpoint, the fetus appears to be a brilliant place to infect. For, as the host grows, they can remain in the new child's cells and then be passed on to the next generation. While a lot of this discussion is simply speculation, it is an exciting new area of research in which we have a lot to learn.



Saturday, November 11, 2017

Norovirus, asymptomatic? (11/9/17)

The majority of cases of human gastroenteritis are caused by a single bug: norovirus (Norwalk virus). Known as the "winter vomiting bug" or the "winter vomiting disease", this virus is of the Calici family and has been around for sometime, having some twenty-nine different genotypes recorded across three different groups. The earliest cases of labelled gastroenteritis likely caused by this virus were in the late 1920's (documented by a fellow named Zahorsky); in the late 1962, however, a notably large outbreak of gastroenteritis causing nausea, diarrhea, and vomiting (lasting anywhere from half of a day to a full day) popped its head up in Norwalk, Ohio, giving the virus its common name. It wasn't until four years later, however, that the virus was isolated and imaged using EM technology, giving the scientific community a name, a particle, and a rudimentary structure to explain this common infection with a vast array of transmission techniques (aerosolization via vomit, fecal-oral, fomites, water-borne, food-borne (including filter feeders)).
Furthermore, past cases of asymptomatic infection are well-described. Indeed, it has been shown that even asymptomatic individuals are capable of shedding virus into their surrounding environments. But, a new article posted by a Japanese virology team has discovered that more people are likely asymptomatic norovirus carriers than previously anticipated or, at the least, the asymptomatic carriers are more important to information than previously thought. This team collected stool samples from 512 asymptomatic individuals in Indonesia, finding that 14 of them had norovirus infections (and were likely able to shed infectious virus). Additionally, it was found that some individuals had signs of recurrent/repeated infection by the same or different strains of the virus (though the ones detected were all of the same genotype group).
This study's conclusions, therefore, indicate that norovirus infects individuals asymptomatically at a much higher rate than believed to be the case. While this was performed in a subtropical climate, it could have implications on the the broader study and assessment of norovirus's viral profile.

Hate to noro see-ya-go, but peace out V

-javarcia ivory

Thursday, November 9, 2017

ARBO viruses and Global Warming

The effects of global warming are far-reaching, yet in our rather unfortunate political ~climate~, it is receiving little recognition as a problem on the rise. The article I found is largely focused on anthropomorphizing the earth and comparing it to an ailing patient whose temperature is climbing incrementally. In a rather interesting analogy, I thought "Hmm, if we are causing global warming by hijacking and using earth's resources in a profligate way, we MUST be considered viruses!!" However, the article mentioned something a bit more relevant and brought up the fact that global warming may be contributing the rise in incidence of conditions associated with ARBO viruses. 

According to a former environmental director of the CDC, the incidence of dengue fever has doubled every decade since 1990 with 58.4 million cases and 10,000 deaths in 2013. This could probably be tied to the fact that warmer weather for prolonged periods of time and changes in climate may allow mosquitoes that transmit the virus to live in more places and bite for longer. A similar effect could be seen in ticks, another arthropod vector. This article further establishes how disease is a function of the host, pathogen, and the environment, making environmental consciousness a necessary measure in ensuring that human disease is mitigated.