More than 100 people are sick in a new outbreak of infections caused by the microscopic Cyclospora parasite, but federal officials have not yet determined the source.

As of July 6, the Food and Drug Administration reported 105 patients had been confirmed in the outbreak. The agency has not reported where the patients live.

Public health officers from the FDA have begun sample collection and analysis, but the agency has not reported what food or foods are being tested.

The new outbreak of Cyclospora infections is the third the FDA has reported so far this year. One of the investigations has been closed without the agency determining the source of the microscopic parasite.

The Centers for Disease Control and Prevention is tracking another outbreak that has sickened 210 people across 22 states as of its most recent update in June. Thirty people in the outbreak have been so sick they required hospitalization.

The CDC first reported on the outbreak on May 25. The first date of onset of the infections was April 1. No specific food items have been identified as the source of the parasite.

The other active Cyclospora outbreak investigation underway by the FDA continues to slowly log more patients. As of this week the outbreak sickened 37 people, up one from the past week. The FDA has not discovered the source of the parasite in this outbreak.

Cyclospora infections generally increase in the summer months but can occur at any time. In the past the infections have been traced to fresh produce such as cilantro and lettuce.

Food safety experts say there’s no evidence that washing produce will remove the parasite.