para>Pregnant women do not have more severe disease or increased susceptibility; however, the developing fetus could be at risk for microcephaly and other congenital abnormalities (4).
Pregnant women who have traveled to an area with ongoing Zika virus transmission should have Zika IgM antibody measured 2 to 12 weeks postexposure to detect infection, even if asymptomatic (4).
Pregnant women with an illness consistent with Zika virus disease during or within 2 weeks of exposure, Reverse-transcriptase-polymerase chain reaction (RT-PCR) (<7days after symptoms onset) of maternal serum, or Zika IgM (>4 days after onset of symptoms). Additional tests may be needed to rule out cross-reactive antibodies (4).
Pregnant women with Zika virus infection should be evaluated by a specialist (4).
Amniocentesis and ultrasounds may be recommended to assess for fetal infection and/or congenital malformation (4).
BREASTFEEDING for mothers with Zika virus infection
Zika virus RNA has been identified in breast milk.
No cases of Zika transmission associated with breastfeeding have been reported (5).
Current evidence suggests benefits of breastfeeding outweigh theoretical risks to infants.
RISK FACTORS
People living in, or traveling to, an endemic area, not previously infected. Immunity will likely develop after initial infection.
GENERAL PREVENTION
- No vaccine or antiviral therapy is currently available.
- Prevention via insect repellents/mosquito control and clothing that minimizes skin exposure, especially during daylight hours.
- Pregnant women should consider avoiding travel to areas with ongoing Zika virus outbreaks.
- Male partners exposed to, or infected with, Zika virus should use condoms correctly and consistently or refrain from sex with pregnant women.
DIAGNOSIS
HISTORY
- 20% of person infected with Zika virus develop symptoms.
- Fever, myalgia, joint pain, conjunctivitis, retro-ocular pain, maculopapular rash are common symptoms (two or more usually present), self-limited in most instances.
- Incubation period is not well understood but likely short.
- Severe disease requiring hospital admission is uncommon; mortality is very rare.
- Travel history to area with outbreak
PHYSICAL EXAM
- Exam findings nonspecific and overlap with other viral infections (dengue can cocirculate)
- Maculopapular rash can be local or diffuse.
- Conjunctivitis
DIFFERENTIAL DIAGNOSIS
- Dengue
- Chikungunya
- Malaria
- Rickettsia
- Leptospirosis
- Enterovirus, adenovirus, parvovirus
- Group A Streptococcus
- Rubella, measles
DIAGNOSTIC TESTS & INTERPRETATION
- The FDA has issued an emergency use authorization for the CDC's Zika virus ELISA for qualified labs.
- Testing in the United States should be done in consultation with state health departments.
- RT-PCR (6)
- Should be done within 7 days after symptom onset
- Sensitivity of RT-PCR is high due to high-level viremia.
- Serology for Zika virus-specific IgM (ELISA)
- Sample should be obtained at least 4 days after symptom onset.
- IgM antibodies present at least 2 weeks after exposure; persist for at least 12 weeks.
- Cross reactivity with other Flaviviruses such as dengue and yellow fever viruses can generate false-positive result, as can previous vaccination with Japanese encephalitis virus vaccine.
- Serum and/or cerebrospinal fluid (CSF) can be sent to CDC for RT-PCR, serology, and viral isolation.
- Other body fluids (urine, amniotic fluid, semen, saliva) can be tested for RT-PCR and viral isolation.
TREATMENT
GENERAL MEASURES
- Usually mild and self-limited infection. Treatment is supportive.
- Aspirin or other NSAID use should be avoided if dengue infection is possible.
- Persons with Zika virus infection should use insect repellent to avoid additional bites, as this can lead to person-vector-person spread.
COMPLICATIONS
- Increases in Guillain-Barr © syndrome (GBS) have been reported in areas with Zika virus transmission and a link is possible (7).
- Twenty-fold increase in microcephaly in infants, and other congenital malformations were observed with Zika virus infection in Brazil, although causality has not been definitively determined (8,9).
ONGOING CARE
- Zika virus disease is a nationally notifiable disease, and health care providers encouraged to report suspected cases to their state health department.
- Lab-confirmed cases should be reported to CDC to assess and reduce the risk of local transmission to prevent further spread of the disease.
REFERENCES
11 Duffy MR, Chen TH, Hancock WT, et al. Zika virus outbreak on Yap Island, Federated States of Micronesia. N Engl J Med. 2009;360(24):2536-2543.22 Musso D, Nhan T, Robin E, et al. Potential for Zika virus transmission through blood transfusion demonstrated during an outbreak in French Polynesia, November 2013 to February 2014. Euro Surveill. 2014;19(14).33 Hills SL, Russell K, Hennessey M, et al. Transmission of Zika virus through sexual contact with travelers to areas of ongoing transmission-Continental United States, 2016. MMWR Morb Mortal Wkly Rep. 2016;65(8):215-216.44 Fleming-Dutra KE, Nelson JM, Fischer M, et al. Update: interim guidelines for health care providers caring for infants and children with possible Zika virus infection-United States, February 2016. MMWR Morb Mortal Wkly Rep. 2016;65(7):182-187.55 Chan JF, Choi GK, Yip CC, et al. Zika fever and congenital Zika syndrome: an unexpected emerging arboviral disease [published online ahead of print March 3, 2016]. J Infect.66 Faye O, Faye O, Diallo D, et al. Quantitative real-time PCR detection of Zika virus and evaluation with field-caught mosquitoes. Virol J. 2013;10:311.77 Oehler E, Watrin L, Larre P, et al. Zika virus infection complicated by Guillain-Barre syndrome-case report, French Polynesia, December 2013. Euro Surveill. 2014;19(9).88 Brasil P, Pereira JPJr, Raja Gabaglia C, et al. Zika virus infection in pregnant women in Rio de Janeiro-preliminary report [published online ahead of print March 4, 2016]. N Engl J Med.99 Heukelbach J, Alencar CH, Kelvin AA, et al. Zika virus outbreak in Brazil. J Infect Dev Ctries. 2016;10(2):116-120.
ADDITIONAL READING
- Meaney-Delman D, Hills SL, Williams C, et al. Zika virus infection among U.S. pregnant travelers-August 2015-February 2016. MMWR Morb Mortal Wkly Rep. 2016;65(8):211-214.
- Oduyebo T, Petersen EE, Rasmussen SA, et al. Update: interim guidelines for health care providers caring for pregnant women and women of reproductive age with possible Zika virus exposure-United States, 2016. MMWR Morb Mortal Wkly Rep. 2016;65(5):122-127.
- Schuler-Faccini L, Ribeiro EM, Feitosa IM, et al. Possible association between Zika virus infection and microcephaly-Brazil, 2015. MMWR Morb Mortal Wkly Rep. 2016;65(3):59-62.
CODES
ICD10
A92.8 Other specified mosquito-borne viral fevers
ICD9
066.3 Other mosquito-borne fever
SNOMED
Zika virus disease (disorder)
CLINICAL PEARLS
- Clinical illness is generally mild and self-limited; most infections are asymptomatic.
- Dengue virus can be cocirculating and the clinical presentation can be similar; testing to distinguish between the two is suggested.
- Although definitive evidence is lacking, Zika virus is strongly linked to microcephaly in infants infected in utero and GBS.
- Infection appears to induce host immunity.