Officials are warning of an outbreak of a parasitic infection outbreak on Boro Park and Williamsburg that has sickened dozens of people.

A deputy health commissioner told Orthodox media outlets in a conference call Wednesday afternoon that there have been 43 cases of cryptosporidiosis, or crypto for sort, since the end of July. Crypto is a parasitic infection that can lead to one or two weeks of diarrhea, sometimes accompanied by stomachache and low-grade fever.

The official urged people in these neighborhoods to be vigilant about washing hands after using the bathroom and not going into public pools or a mikva with symptoms of the virus.

Asked why the disease was virtually unheard of until recently, the official said that this was the first time it was concentrated in a single community. He also said that lab testing is much more advanced than ever before.