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FACT SHEET: Zika Virus Disease (also known as “Zika fever”; comprises two subtypes – “congenital Zika virus disease” [also known as “congenital Zika syndrome” {CZS}] and “non-congenital Zika virus disease”; caused by Zika virus [ZIKV], which is related to the dengue viruses and West Nile virus)

Date of Publication: July 7, 2016
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Is the initiation of non-invasive dental hygiene procedures* contra-indicated?

  • Yes, if the patient/client is febrile and/or has significant acute morbidity related to non-congenital Zika virus disease.
  • No, if the patient/client has congenital Zika virus disease.

Is medical consult advised? 

  • Yes, if the diagnosis is uncertain and/or the patient/client is not already under medical care.
  • Yes, if Zika virus infection is suspected in a pregnant woman.1

Is the initiation of invasive dental hygiene procedures contra-indicated?**

  • Yes, if the patient/client is febrile and/or has significant acute morbidity related to non-congenital Zika virus disease.
  • No, if the patient/client has congenital Zika virus disease.

Is medical consult advised?

  • See above.

Is medical clearance required?

  • No.

Is antibiotic prophylaxis required? 

  • No.

Is postponing treatment advised?

  • Yes, while the patient/client is acutely ill.

Oral management implications

  • Mode of transmission is primarily by bite of an infected mosquito (principally day-biting types2 that also transmit dengue viruses (DENV) and chikungunya virus (CHIKV); mosquitoes are infected by biting persons with viremia3). The incubation period in humans (i.e., time from mosquito bite to clinical signs/symptoms) is 3 to 12 days. Because of viremia in infected persons (detectable levels of virus being present in a patient/client’s blood for up to a week after symptom onset), transmission is possible through exposure to infected blood. Vertical maternal-fetal transmission in infected pregnant women also occurs, as can human-to-human transmission via semen in receptive vaginal, anal, and oral sex. The virus has additionally been detected in saliva, urine, cerebrospinal fluid, amniotic fluid, and breast milk. While blood-borne and saliva-borne transmission are theoretically possible in the dental hygiene setting, such transmission is highly unlikely with appropriate application of standard infection control precautions. At the time of writing, transmission of Zika virus via occupational exposure in a frontline healthcare setting (i.e., patient/client — healthcare personnel setting) has not been definitively described.4 
  • Although Zika fever is usually self-limiting, the diagnosis is important because of the similarity it has with dengue fever, the severe forms of which can be life threatening. Hence, prompt medical referral is important for a traveller with fever returning from tropical or subtropical locales (where the differential diagnosis might also include chikungunya, malaria and bacterial infections). Acetaminophen should be used for initial fever and pain control until dengue is ruled out (NSAIDs, including aspirin,  being contraindicated in dengue).
  • No vaccine exists to prevent Zika virus disease.
  • Individualized adjustments in dental hygiene care (both in-office and at-home) may have to be made for patients/clients with congenital Zika virus syndrome, because ZIKV infection and/or related microcephaly are associated with disturbances in odontogenesis. As well, patients/clients with ZIKV-related microcephaly often have impaired cognitive functioning and other physical abnormalities.

Oral manifestations

  • In non-congenital Zika virus disease, oral findings are uncommon. Mucous membrane ulcerations may be observed. There are also case reports of palatal petechiae5 associated with thrombocytopenia (low platelet count). Gingival changes, including gingivitis and gingival bleeding, have been reported.
  • In congenital Zika virus disease, alterations in the oral cavity include hypotonia or hypertonia, as well as alterations in lingual mobility (including ankyloglossia). These alterations can interfere with suctioning, swallowing, and lip seal, as well as result in a tendency for affected children to become mouth breathers. Dental anomalies in children with ZIKV-related microcephaly include enamel defects, malocclusion, and alterations in tooth number. Delays in dental eruption, disturbed eruption sequence, eruption cysts, mucosal changes, and bruxism have also been noted. Narrow palate (i.e., constricted maxilla) is a common finding.

Related signs and symptoms

  • Until the mid-2010s, Zika virus was almost unknown in the Americas, being historically found in Africa, Southeast Asia, and the Pacific Islands. After its identification in Brazil and Colombia in 2015, Zika virus spread rapidly throughout South and Central America, the Caribbean basin, and Mexico. It became a global health concern in 2015 and 2016 due to its explosive spread and link with birth defects. Since 2017, cases of Zika virus disease have declined globally, although 89 countries and territories have reported mosquito-transmitted Zika virus infection.
  • Canadian travellers are at risk of contracting Zika virus infection in affected regions. This is a particular concern for pregnant women and women considering becoming pregnant as well as their male sexual partners. The principal Zika mosquito vector Aedes aegypti is common in the Caribbean basin. The Aedes albopictus mosquito has also been implicated as a vector, and this species is widely present outside the tropics. Currently, the Aedes mosquitoes that transmit Zika virus are not definitively established in Canada.6
  • Severe disease requiring hospitalization is uncommon, and case fatality is low. Most infected persons (about 80%) display no overt signs or symptoms.
  • In symptomatic individuals, non-congenital Zika virus infection is usually a mild illness with two or more of acute onset of low-grade fever (less than 38.5 °C); transient arthritis or arthralgia (notably in the small joints of hands and feet) with possible joint swelling; maculopapular rash (possibly pruritic); and non-purulent conjunctivitis (red eyes). Other signs/symptoms include myalgia (muscle pain), headache, retro-orbital pain, nausea, and diarrhea. The flu-like illness usually resolves within 2 to 7 days.
  • Zika virus infection acquired by pregnant women in the first, and possibly into the second, trimester of gestation has been causally linked to severe congenital malformations; in particular, microcephaly7 (small head) and incomplete brain development. Most reported deaths from Zika virus infection stem from these congenital abnormalities. Pre-term birth, miscarriage, and fetal loss are other sequelae of ZIKV infection during pregnancy. Additional problems in infants infected with Zika virus before birth include eye defects, hearing deficits, facial abnormalities, impaired growth, contractures (i.e., decreased joint movement), and spasticity (i.e., stiff muscles). Children with microcephaly and related comorbidities are at elevated risk of seizures.
  • Neurological manifestations associated with non-congenital Zika virus disease are rare. These serious complications of infection typically appear as acute flaccid paralysis a few days after the onset of acute symptoms of Zika infection. For example, Guillain-Barré syndrome8 has been causally linked to Zika virus infection. Other rare neurological complications include brain ischemia, myelitis (inflammation of the spinal cord), and meningoencephalitis.
  • While non-congenital Zika virus infection’s signs/symptoms overlap with those of dengue and chikungunya, persons infected with DENV tend to have more bone and muscle pain, neutropenia, thrombocytopenia, and hemorrhagic manifestations, and persons infected with CHIKV are more likely to have high fever, pronounced joint pain, arthritis, rash, and lymphopenia. Conjunctivitis is more commonly associated with symptomatic ZIKV infection than with CHIKV infection, and not at all with DENV infection.

References and sources of more detailed information


Date: June 1, 2016
Revised: July 20, 2021; April 6, 2025


FOOTNOTES

1 Zika virus does not cause birth defects in every fetus exposed in utero. Among women with confirmed or possible Zika infection during pregnancy in the USA, Zika-associated birth defects occur in about 5% of babies.
2 The mosquitoes responsible for transmission of the virus are not definitively established in Canada due to the climate. As a result, there is no local transmission. All reported cases in Canada have been travel-related.
3 In Africa, the virus is also maintained in a sylvatic cycle involving non-human primates and forest-dwelling mosquitoes.
4 However, transmission related to occupational exposure to Zika virus has occurred in laboratory workers, including by needlestick injury.
5 Petechiae are red or purple spots on the mucosa or skin, which do not blanch to applied pressure. They are caused by extravasation of blood (i.e., hemorrhages). Petechiae are pinpoint to pinhead in size (i.e., 1 to < 3 mm in diameter).
6 In the past several years, Aedes albopictus species have been found in Windsor, Ontario, due to enhanced surveillance. A tiny number of Aedes aegypti adults and larvae have also been detected in this southern Ontario area. It is currently unclear whether populations of these species have been able to over-winter in Windsor or if they are being repeatedly introduced through cross-border transportation between the USA and Canada. All of the Aedes mosquitoes in the Windsor area have tested negative for Zika virus.
7 Some babies who do not have microcephaly at birth may develop it later. Furthermore, some infants might look healthy at birth but can develop long-term health problems as they grow.
8 Guillain-Barré syndrome (GBS) is rapid onset of muscle weakness caused by the body’s immune system primarily attacking the peripheral nervous system, often following an infectious illness.


* Includes oral hygiene instruction, fitting a mouth guard, taking an impression, etc.
** Ontario Regulation 501/07 made under the Dental Hygiene Act, 1991. Invasive dental hygiene procedures are scaling teeth and root planing, including curetting surrounding tissue.