A woman who traveled to the United States and Canada is the first verified case of the H1N1 flu in Latvia, the Public Health Agency in Rīga has announced.

The woman returned to Latvia on June 21 on a Berlin to Rīga flight on airBaltic, the agency said in a June 23 press release. The woman exhibited symptoms on the flight and was hospitalized as soon as the flight landed.

The agency has recommended that passengers who were on the flight monitor their health during the next five days. Symptoms of H1N1, according to the World Health Organization (WHO), are flu-like and include fever, cough, headache, muscle and joint pain, sore throat and runny nose. If such symptoms are observed, a spokesperson for the Latvian agency said, the person should contact their family physician or the Public Health Agency’s epidemiologist at +371 67271738.

Health officials were prepared for this first case in Latvia, the agency said in the press release. The agency has notified German officials of the case so they can organize assistance for passengers who traveled with the woman from Canada to Germany.

WHO on June 11 labeled the spread of the virus as a pandemic.

“Globally, we have good reason to believe that this pandemic, at least in its early days, will be of moderate severity,” WHO Director-General Margaret Chen said in a statement. “As we know from experience, severity can vary, depending on many factors, from one country to another. On present evidence, the overwhelming majority of patients experience mild symptoms and make a rapid and full recovery, often in the absence of any form of medical treatment.”

According to WHO, a total of 52,160 cases of H1N1 have been reported around the word as of June 22. In all, 231 people have died as a result of the virus. No cases of the virus have been reported in Lithuania, but Estonia has had five. The United States, Mexico and Canada remain the top three countries in the number of infections.