BY DR. SARFRAZ ALY, Infectious Disease physician, Houston Methodist Sugar Land Hospital
These days, viruses seem to move faster than medical science, always staying one step ahead of researchers and physicians.
Not long ago, we were introduced to the West Nile virus. Then came the SARS epidemic in 2003. These viruses created worldwide fear. Now, we are faced with another serious challenge, known as the Zika virus. This virus has already created a great deal of concern in the Caribbean and throughout South America, and now there are worries it could spread to the U.S.
The Zika virus isn’t new; it was discovered in 1947 when scientists were researching yellow fever in Africa. The researchers found a monkey that had developed a fever while caged in the Zika Forest; they isolated a virus that was unique when compared to yellow fever. Given its place of discovery, it was appropriately named “Zika.”
The first human case was identified in 1954, in Nigeria. Following this, in 2007, there were a few more human cases found in Africa and Southeast Asia.
The Zika virus comes from the flavivirus family. It is spread from person to person by mosquitoes. Zika can cause a series of symptoms in the host ranging from flu-like symptoms to death. Major catastrophic effects occur in pregnant women, leading to neurological defects in the newborn, specifically microcephaly, or incomplete brain development. As of January 2016, more than 2,000 cases of microcephaly were reported among newborns born to Brazilian mothers that had been infected with the Zika virus. This number is a 20- fold increase compared to the previous year.
Once infected, the most common symptoms are low-grade fever, maculopapular rash, joint pain, and conjunctivitis. Most people brush it off as a common cold; very rarely do patients end up in the hospital. However, when a pregnant woman is infected with the virus, it can be devastating to the newborn. The virus is presumed to pass from mother to fetus during pregnancy including intrauterine transmission resulting in congenital infection, as well as intrapartum transmission from a viremic mother to her newborn.
Zika virus RNA has also been detected in blood, urine, semen, cerebrospinal fluid, amniotic fluid, and breast milk.
Diagnosing patients is a two-part process. First, the patient’s travel history is taken, and then, if the patient has indeed been in an area where the Zika virus is active, he or she is can take a RT-PCR on virus RNA or serology for IgM. These tests are time sensitive and has a window of positivity during the time of infection.
However, these tests should be interpreted with caution, since there can be crossreactivity with other viruses from the same family, such as yellow fever, dengue, and chikungunya.
As of today, there is no preventive vaccine available or specific treatment for patients with the virus. The best course of action is prevention, but once a patient is identified as having the virus, doctors typically focus on management of symptoms and primarily prescribe plenty of rest and fluids.
It is important to avoid all NSAIDs (nonsteroidal anti-inflammatory medications) until it is confirmed that the patient does not have dengue virus, which is associated with hemorrhage since NSAIDs can promote bleeding.
The first reported case of Zika virus in the United States occurred in Hawaii. The patient was living in Brazil early in her pregnancy when she contracted the virus. After moving to Hawaii, she gave birth to a microencephalopathic child. Since then, infected patients have been identified in several states.
As of this month, the CDC has released a travel warning for 14 countries in the Caribbean and Latin America. The CDC has particularly cautioned pregnant women for this serious birth defect.
Health officials encourage individuals to protect themselves from the Zika virus by:
• Eliminating areas of standing water – these are prime mosquito breeding sites.
• Wearing protective gear – long pants and long-sleeve shirts can be an effective barrier against mosquito bites. Since the mosquitoes that spread the Zika virus are aggressive throughout daylight hours, it is important to have protective clothing on whenever you are outside.
• Using insect repellent – any brand that contains DEET is highly recommended.
In a major metropolitan area such as Houston, we are likely to encounter travelers and visitors from all parts of the world. Staying aware of and prepared for new viruses such as Zika is a necessity to combat the spread of disease locally.