Affecting several workers at the meat processing facility in the town of Passo Fundo, in the state of Rio Grande do Sul, the outbreak follows several others in the United States in recent weeks, including at some JBS-owned plants.

The plant has not been shut but it is being investigated by the labor prosecutor's office, the source said. A report by news website UOL citing the municipal health authorities said they want the immediate closure of the plant.

The source denied a report by Brazilian news webiste UOL that two family members of workers had died from the disease, adding that the number of people infected at the facility was "less than the 19" that UOL had reported. The source declined to provide an exact number of infected people.

In a statement responding to queries about the Passo Fundo plant, JBS said it was following guidelines from local health authorities and keeping strict controls at its processing plants, distribution centers and offices to avoid contamination from the novel coronavirus.

But it declined to comment on the cases of COVID-19 affecting its employees and said nothing specifically about Passo Fundo, which employs a total of 2,600 workers.

As of April 18, that JBS plant had seven confirmed cases of COVID-19, including one person in critical condition, according to a municipal health department statement published by UOL.

Reuters could not reach the department, Passo Fundo officials or the labor prosecutors for comment on the matter.

Some 78 JBS employees at the facility had been removed from work for showing flu symptoms, the department said, according to UOL's website.

JBS declined to comment on calls to close its Passo Fundo plant.

Noting that food production is considered one of the essential activities authorized to operate even amid coronavirus lockdowns, JBS said it had sought to keep operations running safely.

On Monday, JBS indefinitely closed its Worthington pork plant in Minnesota as the COVID-19 began to affect employees of meat facilities across the United States.