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In one of the largest outbreaks in the United States in recent years, Cyclospora parasites have so far sickened more than 600 people across 22 states, with 43 people treated in hospital, according to the latest update by the U.S. Centers for Disease Control and Prevention (CDC).

Analyses of the outbreak have led investigators to the conclusion that the majority of cases were linked to a salad mix produced at Taylor Farms de Mexico but many of the recently reported cases, identified in Texas, could not be linked to the same products, the CDC said in its report. These patients are being interviewed by CDC and local health officials about a possible common source of the Cyclospora, such as a restaurant in which they have eaten.

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The CDC explained that it is not uncommon for cases of the same disease to be traced to different sources, especially in peak seasons. This means that it is probable that the recent Texas cases are unrelated to the bigger outbreak that started in June.

Officials from the FDA and Mexican authorities carried out an environmental assessment at Taylor Farms' processing facility earlier this month, concluding that production met industry standards. As a result, the company was allowed to resume its export of leafy greens and salad mix to the United States on August 25 but inspections will continue.