Friday, January 11, 2019

A Tale of Two Flaviviruses

Virology in 2016 and 2017 saw a great deal of attention paid towards Zika Virus (ZIKV) outbreaks in the Americas. In addition, recent introduction of West Nile virus to the Americas as of 1999 sees the field of virology and infectious disease adapting to the potential for these infections in a wide variety of patient populations. Work very recently published by Robinson, Enriquez, and Ho synthesized a body of work surrounding the development of WNV and ZIKV in the Americas, specifically as infection and standards of treatment apply to Solid Organ Transplantation (SOT) patient populations. Given the knowledge that WNV and ZIKV are both flaviviruses, the analysis of incidence and epidemiology involved in flavivirus infection in SOT patients is essential to the development of therapeutic techniques for these types of infections. This review is novel in that it holistically reviews cases of flavivirus infection in SOT, where donor-derived disease and increased disease severity are continuing to be fully understood in immunocompromised patient populations. In analyzing these two sources of disease within the same context as a viral family, insight was gained as to the progress that has been made in the field regarding SOT infectious disease as a whole and suggests potential next steps for development of diagnostics and treatments for flaviviruses. As clinical and scientific understanding of this virus develops, it is essential for practicing physicians to continue to develop protocols to protect SOT and immunocompromised patients, in addition to driving research into the afflictions that do not have optimal treatments. Work continues to try and develop vaccines and treatments for the diseases caused by these flaviviruses, and has resulted in many new types of Immunoglobulin based assays for the detection of viral titers in patients. This work is especially important for the immunocompromised patient and SOT communities, as limited data suggests that both WNV and ZIKV infections become exaggerated and more dangerous for these populations. Future work also continues to focus on the treatment of mosquito vectors to prevent their spread of the disease, with researchers finding new ways to either combat the disease within the mosquito or to combat the mosquito itself, much like the work of those combatting Yellow Fever in the late 1800's.
Source: Robinson ML, Enriquez K, Ho DY. A Tale of Two Flaviviruses: West Nile Virus and Zika Virus in Solid Organ Transplantation. OBM Transplantation 2019;3(1):32; doi:10.21926/obm.transplant.1901038.

~Kyle Enriquez

Sunday, September 23, 2018

Investigators Uncover a New Approach to Target Herpesviruses

Herpesviridae is a family of viruses that includes the infamous herpes simplex 1, herpes simplex 2, mononucleosis, and chickenpox/shingles. Lesser known is cytomegalovirus (CMV), a virus that infects over 50% of adults over the age of 40 and sometimes causes reinfection via different strains. The oblivion to infection is likely due to CMV’s lack of symptoms, at least in healthy individuals, that is. Infants and those with compromised immune systems can suffer birth defects or transplant failures as a result of CMV.

Recently, the Proceedings of the National Academy of Sciences of the United States of America (PNAS) published a paper which details CMV’s replication mechanism. Scientists previously knew that in addition to bringing its own genetic material into the cell, CMV also brought a tegument protein which allows for sustained lytic expression called PP71. However, because PP71 has a lifespan of a couple hours, they’d been confused about how replication is carried out in such a short period of time. This is where a newly discovered protein, IE1, comes in. Positive feedback of IE1 further sustains lytic expression, ‘taking over’ for PP71. To test this, different levels of IE1 operating under designated breakdown times were applied to synthetic CMV: normal degradation causes normal, efficient replication, but, as expected, faster degradation causes poor replication. These findings might relevant to the mechanisms of other more severe herpes viruses that are more exigent of a cure.

-Isabella Duan

Wednesday, September 19, 2018

VITN Blog #3: Hepatitis A Outbreak

When we often speak of viruses in class, the infections we talk about occur mostly in other countries. If they do happen in the United States, it is often the effect of lack of vaccination. However, according to a recent report on, Hepatitis A has hit the United States.

The Kentucky Cabinet for Health and Family Services Department for Public Health has begun warning citizens about a Hepatitis A outbreak that started on November 2017 in Kentucky. As of September 8, 1701 people have turned up with Hepatitis A infection, 952 people have been sent to the hospital, and 14 people have died. Those who are mainly affected include drug users and homeless individuals. The virus has been passed from personal contact. It is thought that this outbreak has caused infections in Utah and California. The Jefferson county has had 603 infected individuals, the most of any Kentucky county.

Patients are being given supportive care. There is a vaccine for Hepatitis A. Symptoms include fever, abdominal pain, jaundice, and gray stool.

For more information:

-Kyle Feliciano

VITN Blog Post #3: Zika as a Potential Treatment for Glioblastomas

Glioblastomas, a malignant tumor affecting the brain or spine, are currently incurable. Many die each year from the fatal brain cancer. The recurrence is high, meaning that the cancer has a high tendency to return even after surgery, radiation and chemotherapy. Currently, researchers are naming glioblastoma stem cells (GSCs) as the culprit for this recurrence. However, a team of international researchers has made an interesting hypothesis: zika could target these GSCs.

The outbreak of Zika led to the important discovery of microcephaly in newborns. This is because the virus neural progenitor cells in the fetus of infected mothers. The hope was to have the zika virus specifically target the GSCs because they have similar properties to the cells that the zika virus attacks naturally. A study done on mice models showed that the virus could kill GSCs without posing much harm to differentiated normal brain cells.

Then, the team went on to determine if there was a way for the zika virus to be used without damaging the human body. A live attenuated zika vaccine called ZIKV-LAV was created by researchers at the University of Texas Medical Branch and has shown to fight infection while being harmless to its host. To see if the vaccine could work against GSCs, they inserted both GSCs from humans and the virus into mouse models. Mice that only got the virus developed tumors, while the onset of tumor development in mice that got GSCs and the virus was significantly delayed. This shows promise in the field of oncology. Hopefully, with further research, we could take something that’s bad and turn it into something life-saving.

Read more here:

  • Noah Magbual

VITN Blog Post #3: “CRISPR screen identifies gene that helps cells resist West Nile, Zika viruses”

As we approach the end of SoCo, it is such a heartwarming feeling to read the news and actually be able to make connections to things I have learned from class or speaker presentations. After briefly discussing CRISPR-Cas9 gene editing technology and making my virus model that represented the Flaviviridae family, I found an article about a team at UT Southwestern that used CRISPR to identify the IF16 gene that can potentially inhibit flaviviruses. While other groups have already located genes that are present during an infection, this is the first time that an inhibitor has been found using CRISPR. These genes have been researched in cell cultures using liver cells and confirmed using kidney and epithelial cells. Other inhibitor proteins have been identified by the same lab, but the ability to use CRISPR increases precision and opens doors for more research into how we could possibly treat or prevent transmission of diseases like Zika and yellow fever. All very exciting research, especially as we see West Nile fever spread through the United States and yellow fever rampage through Brazil.

- Jen Vu

VITN Blog Post #2: “Expedited Partner Therapy: Combating Record High Sexually Transmitted Infection Rates”

Sexually transmitted infectious (STIs) have been on the rise in the United States in the past couple years, evident from the 1.59 million new cases in 2016. After hearing about the HIV crisis in Zimbabwe from Caroline Maposhere, learning about stigma around AIDS from Dr. Michael Gottlieb, and listening to my peers present about PrEP and health disparities, I was inclined to learn more about why we aren’t doing better in this day and age. This article from the the American Public Health Association discusses the merits and challenges associated with Expedited Partner Therapy (EPT). In their words, EPT is “a health care practice that allows providers to give a prescription or medications to the heterosexual partners of patients diagnosed with chlamydia or gonorrhea without testing or examining the partner.”

EPT is currently available in 41 states and Washington D.C. However, not many patients know about this treatment, and it is typically not a subject that most physicians bring up voluntarily. EPT is championed for it ability to literally reach a wider audience of people without needing to bring people in to a physical office. Although there are pros to this, it perpetuates existing stigma around sexual health and contraceptives. Furthermore, there is still hesitation to talk about sexual activity and preferences in an empowering and non-awkward way, especially with a health-care provider. Likewise, some physicians may be uncomfortable prescribing without seeing the patients. Although this method has been thought to be cost-effective because it reduces costs of clinic visits, many insurance companies do not cover EPT. Partners may not be pay for their own prescriptions if it is not covered. If we were to make this work in the future, it would require more effort from all parties involved to enforce implementation.

Read the original publication here:

- Jen Vu

VITN Blog #3: ELISA and RT-qPCR as diagnostic tools for Zika

The Zika epidemic that spread like wildfire in Central and South America produced extraordinary levels of panic among local populations and anxiety in nearby countries such as the United States. Some athletes even withdrew from the 2016 Olympic Games held in Rio de Janeiro for fear of contracting the virus. Zika infection does not generally leave long-lasting effects in either men or women not trying to conceive, but the most devastating images to emerge from the epidemic were of infants born to Zika-infected mothers. Many suffer from microcephaly, i.e. small head size due to abnormal brain development. These children often experience severe developmental delays, but one symptom not as acknowledged in the popular media is epilepsy, a seizure disorder.

This study examined the prevalence and severity of epilepsy in a cohort of infants with congenital Zika infection. About two thirds of infants did have some type of epilepsy, and the authors went on to characterize the seizure type, use of antiepileptic drugs, and electroencephalographic features. One notable characteristic was that the infants’ epilepsy was usually early-onset and drug-resistant, indicating a systemic and persistent disruption of normal brain function due to viral action on the growing fetus. However, I was most interested in the two techniques the authors used to diagnose Zika infection in the serum and cerebrospinal fluid samples obtained from the infants and their mothers: enzyme-linked immunosorbent assay (ELISA) for IgM antibody capture and quantitative reverse transcriptase polymerase chain reaction (RT-qPCR) assay for detecting Zika’s genome.

In class, we discussed the distinction between IgM, IgG, and IgA antibodies. IgM are found as a result of recent infection, IgG as a result of previous exposure to disease or vaccination, and IgA in bodily secretions (live, attenuated vaccine produces IgA while inactivated vaccine does not). Dr. Ben Pinsky had briefly summarized the mechanism of ELISA: place antigen on a solid support, add the patient serum, add an antibody conjugated to an enzyme, add the substrate of that enzyme, and measure the resulting color change. ELISA is a common protocol in serology, which seeks to identify antibodies in the blood serum. Dr. Pinsky mentioned several problems with this approach, including cross-reactivity between antibodies to related viruses (e.g. Zika and another member of the Flaviviridae family) and the persistence of IgM antibodies past the acute period of infection. Therefore, IgM antibody capture cannot be used on its own for diagnosis of Zika.

We are all familiar with the basic biochemical principles underlying PCR, which uses DNA as its starting material. RT-qPCR exploits these same rules, but with RNA instead. Under the Baltimore classification, Zika virus is in Group IV: it has positive-sense single-stranded RNA. As a result, PCR cannot be used for amplification of Zika’s genetic material, creating a need for RT-qPCR. Since RT-qPCR is dependent on nucleic acids, it is more specific than serology (according to Dr. Pinsky, such molecular diagnostic tools are steadily replacing older, more conventional ones like ELISA). RT-qPCR first uses reverse transcriptase to generate complementary DNA (cDNA) from the viral RNA template. That cDNA can then undergo PCR for amplification and further analysis such as sequencing for identification of Zika. Interestingly, RT-qPCR can be performed in just one step (in which reverse transcription and PCR occur in a single tube) or two, in which the reactions are separate. The number of hours that RT-qPCR takes varies depending on the chosen assay, but its analytical sensitivity makes it extraordinarily valuable for diagnosis.

The use of these two diagnostic techniques in this study demonstrates how important technological advances are to scientific investigation, especially in the field of infectious disease.

Study: “Epilepsy Profile in Infants with Congenital Zika Virus Infection” (

- Panos Vandris