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Canada - Zika: long and uncertain screening

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  • Canada - Zika: long and uncertain screening

    Translation Google

    Long and uncertain screening

    The medical profession advises to wait two to six months before conceiving a child

    Sunday, 2 July 2017 08:00
    UPDATED Sunday, 2 July 2017 08:00

    Couples wishing to conceive a child after returning from a trip to a country affected by the Zika should not be too excited about testing for the virus, the results being long and limited, Le Journal noted.

    "The most prudent approach to protecting a planned pregnancy is waiting," says Dr. Guillaume Poliquin, medical advisor for the Public Health Agency of Canada and an infectious disease specialist .

    Despite the existence of screening tests, it remains difficult for returning travelers from an area at risk to escape the prescribed waiting months.

    These blood tests, analyzed in Winnipeg, are for pregnant women and people with symptoms of Zika. However, in 80% of the cases, the affected people are asymptomatic.

    Difficult without symptoms

    Dr. Poliquin is well aware of this reality. But if there are no symptoms, he says, "the chances of having a useful test are reduced." "It's hard to pinpoint when the person was at risk, if they were at risk," he says. In this case, only waiting is required.

    People with "acute symptoms" of Zika may undergo a first test. The latter is effective if it is carried out within 14 days of the appearance of the signs. If the result is positive, the traveler has been infected. If it is negative? "It's uncertain" since the virus can remain in the blood for a longer or shorter period depending on the individual, the doctor said.

    Second test

    A second test must be carried out in travelers who obtain a negative result on the first test. This tool is also used for pregnant women if they do not feel the signs of the disease.
    But the process is long: the sampling must be done four weeks after the return trip, and the analysis takes eight weeks.

    In the case of this second test, a negative result means that Zika did not contaminate the body within three months of the blood test. A positive result will require another screening step to ensure that it is Zika and not another virus such as dengue fever or yellow fever, illustrates Dr. Poliquin.

    Waiting therefore remains the best tool, reiterates the expert. Because Zika can cause microcephaly in the fetus during pregnancy, men have to wait six months before making a baby. The deadline is two months for women. Condom use is advised during these periods, as the virus can be sexually transmitted.


    ■ 103 travel-related cases, including mother-to-fetus transmission
    ■ 13 pregnant women at the time of diagnosis
    ■ No abnormalities in the children of an infected mother
    Source: Ministry of Health and Social Services


    ■ More than 19,800 screening tests
    ■ 299 travel-related cases
    ■ 3 cases of sexual transmission
    ■ 33 cases in pregnant women
    ■ 2 cases of anomaly in children born to a mother infected with the Zika virus
    Source: Public Health Agency of Canada


    * Molecular (research of the genetic material of the virus)

    ■ Requires acute symptoms of the virus (80% of infected people are asymptomatic)
    ■ Must be done between 3 and 14 days after onset of symptoms
    ■If positive: confirms the presence of the virus
    ■If negative: does not confirm absence of virus
    * Serology (looking for antibodies against the virus)
    ■For people with symptoms who have had a negative molecular test and pregnant women
    ■ Must be done four weeks after the return trip (8 weeks for analysis)
    ■If positive: presence of Zika or other virus. Another validation test must be performed
    ■ If negative: the virus did not infect the organism within three months before collection

    Source: Public Health Agency of Canada
    "Safety and security don't just happen, they are the result of collective consensus and public investment. We owe our children, the most vulnerable citizens in our society, a life free of violence and fear."
    -Nelson Mandela