At least 11 people were checked over by medical personnel after they became sick aboard a Toronto-bound Air Transat flight from Holguin, Cuba on Friday afternoon.

This is the fourth flight to return to Ontario from Cuba since Tuesday with sick passengers on board. Two planes landed at Toronto's Pearson International Airport, while the other two landed in Ottawa.

Public health officials are investigating the source of the gastrointestinal illness, which causes nausea, vomiting, diarrhea and fever.

The sick vacationers stayed at at least four resorts in Cuba and some of them reported feeling ill while they were on the Caribbean island.

In Friday afternoon's incident, passengers were examined by public health nurses on the plane as it sat on the tarmac at Pearson International Airport shortly after landing at 3 p.m.

No one was allowed to leave the plane until the ill passengers were assessed and health officials learned more about their condition.

Peel EMS officials were on standby, but no one had to be taken to hospital. The plane wasn't quarantined.

Earlier incidents

The Public Health Agency of Canada (PHAC) released the following information about three other incidents that occurred earlier this week:

  • Seven ill passengers were on board a Cuba-to-Ottawa flight Tuesday
  • Twenty passengers were ill on a Toronto-bound flight Thursday night
  • Twelve sick passengers were on board a plane that landed in Ottawa on Friday morning

In those cases, all of the passengers were examined by Health Canada nurses on board the planes. In each case, no quarantine was necessary.

After learning of Friday's incident, Margo Clarke told CP24 she became ill while vacationing in Holguin earlier this month.

Clarke said she ate a seafood dinner at a resort and was sick for most of her seven-day vacation, which began Jan. 12.

"The (illness) was really not a welcome part of the holiday," Clarke said.

Clarke said she endured vomiting, diarrhea and a gut-wrenching pain in her stomach, and at least 10 other people told her they suffered similar symptoms at the resort.

On the flight home, people were in "various degrees of having been sick" with a 24-hour stomach bug, while a woman was "vomiting violently" most of the plane ride home, Clarke said.

She said public health officials weren't notified and passengers exited the Sunwing Airlines plane on their own after it landed in Toronto.

Take precautions before you travel: health officials

PHAC suggests people take the following precautions before they travel abroad:

  • Consult a doctor, nurse or health-care provider, or visit a travel health clinic six weeks before you travel to assess any health-related needs, receive advice on how to prevent illness and injury, and discuss any health concerns
  • Check the Public Health Agency of Canada's website for travel health notices
  • Obtain full travel health insurance coverage for both illness and injury
  • Carry proof of the need for any prescription drugs
  • For travel security, view travel reports on the Foreign Affairs and International Trade Canada website

According to PHAC officials, people who are sick when they return to Canada or people who have been near someone with a disease that could be spread to others must inform a customs officer or a quarantine officer.

People who are sick when they return or were sick while they were away should see a nurse, doctor or health-care provider and inform them of the country or countries they visited and the medical care they received, if any, according to PHAC.

With files from CP24's Katie Simpson

@ChrisKitching is on Twitter