The disease is transmitted to humans through the bites of a midge bug, or no-see-um, and possibly mosquitos. Symptoms include fever, severe headaches, vomiting and dizziness.

The virus is not new to the Americas, but its appearances in Brazil, Bolivia and Cuba are unprecedented.

There are concerns that Oropouche virus can be transmitted from a pregnant person to their unborn baby, with negative pregnancy outcomes, including stillbirth, reads the government health notice, which adds that pregnant travellers should follow its bug-bite prevention advice closely.

Travel-related Oropouche infections (also called OVD or sloth fever) have been reported around the world. Most have been linked to travel to Cuba. Local officials began fumigation campaigns in Havana on Friday, Reuters reported, but those efforts have been thwarted by the countrys fuel shortages.

Those fuel shortages have contributed to an overall advisory to travellers with Cuban destinations: “Exercise a high degree of caution,” officials warn. It’s the second risk level issued by the Canadian government on a scale of four tiers. Above it are “Avoid non-essential travel” and “Avoid all travel.”

The country is facing chronic and severe shortages of food, bottled and publicly-accessible water, medication, fuel, and hard-currency.

Areas outside of tourist destinations are most affected by the shortages, where intermittent blackouts are common, making obtaining services challenging.

Resort areas remain at a level one: “Take normal security precautions.”

More than 20 travellers returning to the U.S. have been infected with OVD, according to an announcement from officials there last Tuesday.

There have been no reported deaths among American travellers. U.S. officials put doctors on notice to be on the lookout for potential spread domestically, though no such spread had yet occurred.

Since the last major outbreak late last year, about 8,000 cases have been reported in Bolivia, Brazil, Colombia, Cuba, and Peru.

The WHO raised alarm over OVD’s appearance in Cuba in June, due to the population’s relative vulnerability to the disease.

“This is the first detection of the disease in the country, therefore, the population is likely highly susceptible and there is a significant risk of additional case detection,” reads the WHO’s risk assessment published on June 11.

“There is a risk of the disease spreading internationally as Cuba is an international tourist destination.”