An outbreak of mumps in northern Manitoba is declining, but infection rates are still abnormally high.
The rate of reported infections in the region declined in September after three consecutive months when nearly 100 new cases were reported.
“For September, it looked like we had 62 cases in the north, which was down from 97 in August,” said Dr. Michael Isaac, chief medical officer for the Northern Health Region (NHR).
In June, 98 cases of mumps were reported in the region, with another 94 reported in July. Typically, between zero and five cases are reported to NHR in a year.
While the numbers
are high, comparatively few cases have been reported in Flin Flon.
“Most communities in northern Manitoba have seen at least a case or two. Flin Flon in particular, we haven’t seen as much activity in Flin Flon as we have seen in some of the other communities in the north. At this point, our case count there is less than five,” said Isaac.
The mumps virus has had a resurgence throughout Manitoba in the past year, with more than 1,000 cases being reported in the province since January. Isaac said the outbreak began in Winnipeg last spring, gradually spreading to other communities from there.
Cases have been found amongst all age groups. The illness is highly contagious and can be spread for as long as three weeks during the period of infection.
Symptoms of the disease include headaches, muscle aches, fever and swollen glands around the neck, jaw and chin.
Isaac also said the rate of complications arising from mumps cases has decreased during the outbreak, adding that few cases of severe side effects have been reported.
Despite the high number of cases, the NHR reports that northern Manitoba has a higher than average rate of people vaccinated for mumps. Cases of mumps have been reported in people who have previously been vaccinated for the illness.
Isaac said the mumps vaccine, like other immunizations, becomes less effective over time.
“There’s no doubt that the length of time after you’ve had your vaccine can play a part in your immunity. It looks like, for example, people who were vaccinated 25, 30 years ago are likely less [immune] than people who were vaccinated last year,” he said.
Smaller, tight-knit communities are more susceptible to highly contagious illnesses like mumps.
“Once you get a case or two in the community, because of that, the spread of the virus is greater,” said Isaac.
“I think the other thing that we have to take into account is, depending on the community, some communities have very high rates of overcrowding in housing stock. Where there’s overcrowding – and it’s not only mumps, it can be other things like tuberculosis and bacterial infections – there tends to be easier transmission in those environments. I think those two things, from a northern perspective, might explain some of the higher numbers we’ve been seeing.”