The Centers for Disease Control and Prevention raised its travel alert to level two on Monday, asking travelers to “practice enhanced precautions” as monkeypox cases have grown to over 1,000 worldwide.

The travel alert encourages people traveling to “avoid close contact” with sick people and animals with skin lesions.

The CDC cautions that the risk to the general public is low but anyone who gets an “unexplained skin rash” should seek medical help.

Cases of monkeypox – a rare disease from the monkeypox virus that causes skin rashes after symptoms like fever and muscle aches – have grown this year. The disease has been spreading undetected, the World Health Organization said last week.

The disease “occurs throughout” Central and West Africa, and infections from the virus occur through skin-to-skin contact, materials with the virus on it, or body fluids, the CDC noted.

The CDC initially recommended face masks to prevent the spread of the rare disease but removed the guidance following social media criticism, the Wall Street Journal reported.

The CDC said it removed the guidance “because it caused confusion,” according to the newspaper, but recommends the use of masks for people at “high risk of contracting monkeypox.”

There have been 1,088 confirmed cases of monkeypox in 29 countries this year as of Tuesday, including 302 confirmed cases in the U.K., the CDC reported.

Vaccines can be used for the monkeypox virus, including ACAM200 and JYNNEOS vaccines that can reduce symptoms but “not prevent the disease,” according to the CDC.