Zeroing in on the Zika Virus
BY WILLIAM L. MILLER, OD, PHD, FAAO
In February, the World Health Organization (WHO) declared the Zika virus infection an international public health emergency. The virus is carried by the Aedes aegypti mosquito, which also transmits the dengue and chikungunya viruses. There have been no reported locally acquired transmissions in the continental United States; there have been cases in the U.S. Virgin Islands and Puerto Rico. There have, however, been 193 travel-associated cases in the United States as of March 9, 2016 (www.cdc.gov/zika). The virus also can be transmitted in-utero, through sexual transmission, and possibly through blood transfusions. The most frequent travel-associated cases have occurred in Florida, New York, Texas, and California.
Signs and Symptoms
Most individuals (80%) infected with the virus lack any symptoms of the disease (American Academy of Ophthalmology, 2016). The most notable associated link has been with microcephaly; other systemic effects are often forgotten. There have also been reported cases of Guillain-Barré syndrome that have likely been triggered by the virus.
General health symptoms are not unlike those found in other viral diseases, which include fever, maculopapular rash, arthralgia, and conjunctivitis. Other effects on the eye are lesser known and infrequently described in the media. Those who manifest systemic symptoms may also have associated ocular effects that may include a nonpurulent conjunctivitis and macular and optic nerve abnormalities.
The latter posterior segment findings were reported in a study by de Paula Freitas et al (2016) in infants who also suffered from microcephaly. Specific ocular manifestations in that report included macular pigment mottling, macular chorioretinal atrophy, optic nerve hypoplasia, increased cup-to-disc ratio, iris coloboma, and lens subluxation.
The CDC recommends that all suspected Zika cases be reported to your respective state health departments. As part of your examination in an at-risk infant, an eye examination along with a retinal evaluation should be performed either prior to dismissal or within one month after discharge (Fleming-Dutra et al, 2016).
Serologic testing (IgM and plaque reduction neutralization) as well as polymerase chain reaction testing by the CDC and selected state agencies can help with the challenge of diagnosis. Recently, the FDA used an Emergency Use Authorization to authorize the use of the CDC’s Zika IgM antibody capture ELISA (Zika MAC-ELISA). Antibodies to the Zika virus manifest within three to four days after the illness starts and can last up to 12 weeks.
As with many viral diseases, prevention is the best strategy for stopping transmission. To start, avoid travel to affected areas; if you must travel to an affected area, take precautions to avoid mosquito bites, and avoid sexual contact or use precautionary measures during sex to prevent transmission of the virus. The CDC recommends that patients who are pregnant avoid travel to affected areas. If pregnant and currently living in or having visited an affected area, the CDC recommends seeing a healthcare practitioner immediately if symptoms of Zika develop.
If non-pregnant patients develop Zika symptoms and have reason to believe that they have been infected with the virus, they should visit their healthcare provider. To manage the systemic effects of the virus, additional palliative measures such as rest, drinking of fluids, and acetaminophen (for fever and pain) should be administered. Aspirin and NSAIDs should not be taken unless dengue fever has been ruled out due to the risk of bleeding in that condition. CLS
For references, please visit www.clspectrum.com/references and click on document #246.
Dr. Miller is an associate dean for academic affairs and professor at the Rosenberg School of Optometry, University of the Incarnate Word. He has received research funding from Alcon and SynergEyes and travel funding from Alcon. You can reach him at firstname.lastname@example.org.