Zika Virus: Points to Ponder?

Author: Charles J. Chase, D.O.

ASA Monitor 03 2017, Vol.81, 18-19.

Charles J. Chase, D.O., is Past President, Florida Society of Anesthesiologists; Anesthesiologists of Greater Orlando, a subsidiary of Envision Healthcare.

An insidious infectious disease has captured world attention and generated fear in the hearts of all pregnant women. Unless you have been living on Mars with no communication to planet earth, the word “Zika” immediately comes to mind. Unfortunately, it is most likely only a matter of time before this disease presents to your OB unit. So how does one treat a patient with active Zika infection?

To understand treatment, one must understand the pathogenesis of the virus. Zika is a member of the flavivirus genus of viruses. This genus includes West Nile virus, dengue virus, tick-borne encephalitis virus, yellow fever virus, Zika virus and several other viruses that may cause encephalitis.1  Flaviviruses are named from the yellow fever virus. Flavus means yellow in Latin (remember ligamentum flavum?). Typical of flavivirus, Zika is a single-stranded RNA virus transmitted by vectors, specifically in this case the Aedes species of mosquitos commonly found in many areas of the United States. Of note, Aedes Aegypti and Aedes Albopictus actively bite both during daylight and evening hours and make themselves at home both indoors and outdoors. Other modes of transmission include sexual relations (both semen and vaginal fluids), maternal-fetal transmission and blood transfusions. Zika RNA is also present in urine, amniotic fluid, saliva and breast milk; however, no cases of transmission from mother to infant through breast milk have yet been documented.2,3  Of concern, West Nile Virus, also a flavivirus, is transmitted via milk ingestion to the newborn.4  Despite this finding, breastfeeding recommendations are unchanged to date.

An interesting issue to ponder is the safety of neuraxial anesthesia in a Zika-infected patient. Current practice suggests that neuraxial anesthesia is not contraindicated if the patient exhibits no active symptoms.5  However, 80 percent of Zika infections are asymptomatic; thus, how is a practitioner to know if the patient harbors an acute infection? As with any bacterial or viral systemic infection, neuraxial anesthesia is contraindicated due to the risk of spreading infection from the blood stream into the central nervous system. Can a case be made for ordering Zika virus testing on every patient undergoing neuraxial anesthesia with the hope of preventing iatrogenic infection?

No known transmission from patient to health care provider has yet been documented; however, in 2016 the Utah Department of Health reported one case of fatal Zika infection with unknown mechanism of transmission to a family member.6,7  All traditional mechanisms of transmission had been ruled out. The family member reported assisting a nurse in repositioning the index patient in bed and wiped his eyes without wearing gloves. No other contact with blood or other body fluids, including splashes or mucous membrane exposure, was reported. Of note, the index case, an elderly family member, had a blood viral load approximately 100,000 times higher than the average level reported in persons infected with Zika virus.8  The index patient developed septic shock with multiple organ failure and died in the hospital two days after discovery of the elevated viral load. This troubling report suggests that Zika may have the capability to have increased virulence associated with atypical transmission patterns.

The question on everyone’s mind is how should the practicing anesthesiologist protect oneself from occupational exposure? Anesthesia providers in the labor and delivery setting should adhere to standard precautions and wear sterile gloves and a surgical mask when placing a catheter or administering intrathecal injections; additional personal protective equipment (PPE) should be worn based on anticipated exposure to body fluids.9  Double gloves might minimize the risk for percutaneous injury when sharps are handled. When double layers of gloves are used for procedures and surgeries, the outer layers often have significant perforations, whereas the inner layers are intact or have many fewer perforations. Although double gloving is not specifically listed as a CDC guideline, it is intimated in associated publications.10  Because patients with Zika virus infection might be asymptomatic, standard precautions should be in place at all times, regardless of whether the infection is suspected or confirmed.11  Might this suggest wearing of facial shields and double gloves for every spinal or epidural catheter placement or potentially Ebola-type protective equipment when caring for a Zika patient?

These questions lead us to ponder current treatment guidelines of confirmed and potential Zika-infected patients. The World Health Organization declared the rapid spread of Zika as a “public health emergency of international concern.”12  The spectrum of those at risk, potential modes of transmission and sequellae of infection may be more expansive than previously recognized. Although current policies will help postpone the spread of this disease, vaccination is the key to prevention. Human clinical trials began in November 2016. The obvious need for basic science research on Zika virus cannot be overstated.

References:

Shi P-Y , ed. Molecular Virology and Control of Flaviviruses. Poole, UK: Caister Academic Press; 2012.

Dupont-Rouzeyrol M, Biron A, O’Connor O, Huguon E, Descloux E . Infectious Zika viral particles in breastmilk. Lancet. 2016;387(10023):1051

Meaney-Delman D, Rasmussen SA, Staples JE, et al. Zika virus and pregnancy: what obstetric health care providers need to know. Obstet Gynecol. 2016;127(4)642-648.

Centers for Disease Control and Prevention (CDC). Possible West Nile virus transmission to an infant through breast-feeding—Michigan, 2002. MMWR Morb Mortal Wkly Rep. 2002;51(39);877–878.

Padilla C, Pan A, Geller A, Zakowski MI . Zika virus: review and obstetric anesthetic clinical considerations. J Clin Anesth. 2016;35:136–144.

Brent C, Dunn A, Savage H, et al. Preliminary findings from an investigation of Zika virus infection in a patient with no known risk factors – Utah, 2016. MMWR Morb Mortal Wkly Rep. 2016;65(36);981–982. [Article]

Swaminathan S, Schlaberg R, Lewis J, Hanson KE, Couturier MR . Fatal Zika virus infection with secondary nonsexual transmission. N Engl J Med. 2016;375(19);1907–1909

Lanciotti RS, Kosoy OL, Laven JJ, et al. Genetic and serologic properties of Zika virus associated with an epidemic, Yap State, Micronesia, 2007. Emerg Infect Dis. 2008;14(8):1232–1239.

Siegel JD, Rhinehart E, Jackson M, Chiarello L, Healthcare Infection Control Practices Advisory Committee. 2007 guideline for isolation precautions: preventing transmission of infectious agents in healthcare settings. Centers for Disease Control and Prevention website. http://www.cdc.gov/hicpac/2007IP/2007isolationPrecautions.html. Updated December 9, 2010. Last accessed January 13, 2017.

Mischke C, Verbeek JH, Saarto A, Lavoie MC, Pahwa M, Ijaz S . Gloves, extra gloves or special types of gloves for preventing percutaneous exposure injuries in healthcare personnel. Cochrane Database Syst Rev. 2014;(3):CD009573.

Olson CK, Iwamoto M, Perkins KM, et al. Preventing transmission of Zika virus in labor and delivery settings through implementation of standard precautions – United States, 2016. MMWT Morb Mortal Wkly Rep. 2016;65(11):290–292.

World Health Organization. WHO Director-General summarizes the outcome of the Emergency Committee regarding clusters of microcephaly and Guillain-Barré syndrome. http://www.who.int/mediacentre/news/statements/2016/emergency-committee-zika-microcephaly/en/. Published February 1, 2016. Last accessed January 13, 2017.