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FACT SHEET: Zika Virus Disease (also known as “Zika fever”; caused 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 morbidity.

Is medical consult advised? 

  • Yes, if Zika virus infection is suspected in a pregnant woman.

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

  • Yes, if the patient/client is febrile and/or has significant morbidity.

Is medical consult advised?

  • See above.

Is medical clearance required?

  • No.

Is antibiotic prophylaxis required? 

  • No.

Is postponing treatment advised?

  • Yes, while patient/client is acutely ill.

Oral management implications

  • Mode of transmission is primarily by bite of an infected mosquito (principally day-biting types that also transmit dengue viruses (DENV) and chikungunya virus (CHIKV); mosquitoes are infected by biting persons with viremia1). 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.2 The Centers for Disease Control (U.S.) outlines guidance in the event of possible occupational healthcare exposure (https://www.cdc.gov/zika/hc-providers/infection-control/managing-occupational-exposures.html). 
  • 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.

Oral manifestations

  • Oral findings are uncommon. Mucous membrane ulcerations may be observed. There are also case reports of palatal petechiae3 associated with thrombocytopenia (low platelet count).
  • In Zika congenital syndrome, alterations in the oral cavity include hypotonia or hypertonia, as well as alterations in lingual mobility that can interfere with suctioning, swallowing and lip seal; this results in a tendency for affected children to become mouth breathers. Slight delay in dental eruption has also been noted.

Related signs and symptoms

  • Until recently, Zika virus was almost unknown in the Americas, being historically found in Africa, Southeast Asia, and the Pacific Islands. Since its identification in Brazil in 2015, Zika virus has spread rapidly throughout South and Central America, the Caribbean basin, and Mexico. It has become a global health concern due to its recent explosive spread and link with birth defects.
  • Canadian travellers are at risk of contracting Zika virus infection in affected regions; this is particularly a concern for pregnant women and women considering becoming pregnant as well as their male sexual partners. The principal Zika mosquito vector Aedes aegypti is very common in the Caribbean basin. Currently, the Aedes mosquitoes that transmit Zika virus are not established in Canada.
  • 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, 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 has been causally linked to severe congenital malformations; in particular, microcephaly (small head) and incomplete brain development. Most reported deaths from Zika virus infection stem from these congenital abnormalities. Other problems in fetuses and infants infected with Zika virus before birth include eye defects, hearing deficits, and impaired growth. Children with microcephaly and related comorbidities are at elevated risk of seizures. 
  • Guillain-Barré syndrome4 has been causally linked to Zika virus infection. Other rare neurologic complications include brain ischemia, myelitis (inflammation of the spinal cord), and meningoencephalitis.
  • While 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


FOOTNOTES

1 In Africa, the virus is also maintained in a sylvatic cycle involving non-human primates and forest dwelling mosquitoes.
2 However, transmission related to occupational exposure to Zika virus has occurred in laboratory workers, including by needlestick injury.
3 Petechiae are red or purple spots on the mucosa or skin, which do not blanch to applied pressure, caused by extravasation of blood (i.e., hemorrhages). Petechiae are pinpoint to pinhead in size (i.e., 1 to < 3 mm in diameter).
4 Guillain-Barré syndrome (GBS) is rapid onset of muscle weakness caused by the body’s immune system 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.