(Reuters) — Chipotle Mexican Grill Inc. shares took a hit on Thursday after best-selling author Eric Van Lustbader revived concerns about food safety at the burrito chain by tweeting that his editor fell ill after eating at one of its Manhattan restaurants.

Company spokesman Chris Arnold said Chipotle had received no current reports of illness in New York City from customers or health departments. Arnold said Chipotle had “very solid health department scores” across New York City.

The New York City Department of Health and Mental Hygiene said it had not received reports of confirmed cases this year of foodborne illness associated with Chipotle restaurants in the city.

The company's sales and stock swooned last year after health officials linked E. coli, Salmonella and Norovirus outbreaks to its restaurants, and the company is still recovering.

The tweet landed the same week the company launched an animated ad that pokes fun at processed fast food, and in which the chain's executive in charge of food giveaways and other sales-boosting promotions was charged with cocaine possession.

Shares of Chipotle fell as much as 3.7% percent in early trading on Thursday after Mr. Van Lustbader, author of “Jason Bourne” novels and other works, tweeted: “This Chipotle thing is still ongoing. My editor ended up in urgent care after being deathly ill all night from eating at Chipotle's.”

The tweet from Mr. Van Lustbader attracted dozens of comments from Chipotle customers and traders. Some criticized him for publicizing the illness and whipping up worry without a confirmed diagnosis of food poisoning. Others simply sought more information.

The author in subsequent posts said he did not own shares of Chipotle and did not know more than his editor told him.

“Not interested in the stock. I'm interested in the health of my editor and friend. Food poisoning always taken seriously,” he added.

The onset of symptoms from botulism, Listeriosis, Salmonellosis, Norovirus and Staphylococcal food poisoning can occur within hours after exposure, while E. coli and some other illnesses typically surface 24 hours to several days later, according to the U.S. Food and Drug Administration.

Chipotle shares closed down 2.6% at $390.78 on Thursday. The company's stock traded above $750 a share before last year's highly publicized food safety lapses.