While there have been cases of Zika virus reported in Canada in returned travellers from countries where the virus is known to circulate, there have been no reported cases of locally acquired Zika virus in Canada.
Zika virus is transmitted by Aedes aegypti mosquitoes, the mosquitoes that also transmit dengue and chikungunya virus. These mosquitoes bite both indoors and outdoors and mostly during the daytime.
The incubation period for zika virus infection is from 3 to 12 days and symptoms last several days to 1 week. Approximately 80% of Zika infections are asymptomatic.
Disease is generally mild and characterized by acute onset fever, maculopapular rash, arthralgia, or nonpurulent conjunctivitis. Disease requiring hospitalization and fatalities are rare.
Treatment is supportive.
Patients should also be evaluated for dengue and chikungunya. Aspirin and other nonsteroidal anti-inflammatory agents should be avoided until dengue can be ruled out to reduce the risk of hemorrhage.
The US CDC algorithm provides specific details RE: “testing for pregnant women with a history of travel to an area with Zika virus transmission, with or without clinical illness consistent with Zika virus disease“.
Patients with symptom onset while in endemic areas, or within 14 days of departure from an endemic area, may be considered for testing.
Generally testing is not indicated in non-pregnant patients after recovery from a self-limiting illness.
The CDC and PHAC currently do not recommend testing asymptomatic pregnant women; if fetal microcephaly or CNS calcification are detected, and risk factors for Zika infection are present, testing should be conducted.
Specimens submitted for Zika virus testing will also be tested for chikungunya and dengue.