Cyclosporiasis Outbreak Investigations — United States, 2013 (Final Update)

October 23, 2013

Investigation Update

Reported cases of cyclosporiasis in the United States have returned to baseline levels; therefore, it is likely that the outbreaks identified during June–August 2013 have ended. The number of reports of persons with illness increased beginning in June and returned to baseline in mid-to-late August.

Investigations in Texas

Epidemiologic and traceback investigations conducted by state and local public health and regulatory officials in Texas, the FDA, and CDC indicate that some illnesses among Texas residents were linked to fresh cilantro from Puebla, Mexico.

Investigating "clusters of illnesses" can provide critical clues about the source of an outbreak. A cluster of illnesses is defined as more than one unrelated ill person (i.e., they do not know or live with each other) who report eating at the same restaurant location, attending a common event, or shopping at the same location of a grocery store before becoming ill. If several unrelated ill persons ate or shopped at the same location of a restaurant or store within several days of each other, it suggests that the contaminated food item was served or sold there. In addition, traceback of suspected food items to identify a common point of contamination may be facilitated by records kept at these locations. Investigators identified more than 70 clusters of illnesses in Texas. Most of the clusters identified in Texas involved two or three ill persons.

During interviews with ill persons in Texas, about 50% reported having eaten fresh cilantro 2–14 days before they became ill. This proportion was significantly higher than that reported among ill persons in Iowa and Nebraska (reported by about 10%), and significantly higher than results from a previously conducted survey of healthy persons in New Mexico where 27% reported eating fresh cilantro in the 7 days before they were interviewed.

Epidemiologic and traceback investigations were conducted at three restaurants and one grocery store location in Texas, where multiple unrelated ill persons reported having eaten or shopped.

Restaurant Cluster Investigations in Texas

Thirty (30) ill persons reported eating at a single Mexican-style restaurant in Fort Bend County, Texas, in the 2–14 days before onset of illness. In this investigation, a case was defined as having onset of diarrhea (≥3 loose stools in a 24-hour period) 2–14 days after eating at this restaurant. Twenty-two (22) ill persons had laboratory-confirmed Cyclospora infection (confirmed cases) and 8 were probable case-patients (case symptoms but no laboratory confirmation). An analytic epidemiologic study was conducted that compared foods eaten at the restaurant by 25 of the persons who became ill versus 65 healthy persons who remained well. Ingredient-level analyses were conducted using meal consumption data and recipes. Four fresh produce ingredients were significantly associated with illness: cilantro, whole onions, garlic, and tomatoes. Since these ingredients were served together in many different dishes, such as salsa, the statistical analysis could not definitively identify which of these ingredients was independently associated with illness. However, fresh cilantro was the only ingredient consumed by all 25 ill persons in this study. In addition, salsa containing fresh raw (uncooked) cilantro was associated with illness, while salsa containing cooked cilantro was not. Fresh cilantro was used in four types of restaurant-produced salsas. The three salsas that were not cooked were significantly associated with illness, whereas the one that was cooked before serving was not (heat can kill Cyclospora).

Consumption of lettuce was not associated with illness in this analysis, and traceback information indicated that lettuce served in this restaurant was not from Taylor Farms de Mexico. Neither red cabbage nor carrots (components of the Taylor Farms de Mexico salad mix linked with illness in Iowa and Nebraska) were used in this restaurant. Preliminary traceback information indicates that Puebla, Mexico, was a source of the fresh cilantro that was served to ill persons in this restaurant.

Investigations were also conducted at two other Mexican-style restaurants in Central Texas. These restaurants were not related to the restaurant in Fort Bend County, not part of the same chain, and not part of a national restaurant chain. A formal analytic epidemiologic study was not conducted among ill persons who had eaten at either location since these clusters had relatively few ill persons (two confirmed and three probable cases who had eaten at one restaurant and two confirmed cases who had eaten at the second). Preliminary traceback information indicates that Puebla, Mexico, was a source of the cilantro that was served to ill persons at both restaurants, and that the lettuce served in the restaurants was not from Taylor Farms de Mexico.

Grocery Store Cluster Investigation in Texas

An investigation was also conducted among four ill persons who reported shopping at a single location of a grocery store in North Texas. All four ill persons reported having eaten fresh cilantro they purchased at this store before they became ill. Shopper card information was available for three (of four) persons, who gave permission for public health officials to retrieve their purchase data. A review of their shopper card records identified that all three had purchased fresh cilantro within 3 days of each other. In addition, all three had purchased the fresh cilantro during the 7–10 days before they became ill, which is consistent with the incubation period for cyclosporiasis. A further review of shopper card records did not identify any other foods purchased in common among these ill persons. Preliminary traceback information indicates that Puebla, Mexico, was a source of fresh cilantro available for purchase at this grocery store location during the period when the persons who became ill purchased it.

Conclusion

The findings in the investigations suggest that there was more than one outbreak of cyclosporiasis during June–August 2013 in the United States. Restaurant-associated illnesses in Iowa and Nebraska were linked to salad mix from Taylor Farms de Mexico in Guanajuato, Mexico. Some illnesses in Texas were linked to fresh cilantro from Puebla, Mexico.

September 24, 2013

Case Count Update

As of September 20, 2013 (5pm EDT), a total of 643 ill persons with Cyclospora infection have been reported from 25 states. Since the last update on September 17, 1 additional ill person was reported.

Ill persons range in age from less than one year to 92 years, with a median age of 52 years. Fifty-seven percent (57%) of ill persons are female. Among 581 ill persons for whom information is available, 45 (8%) have reported being hospitalized. No deaths have been reported.

Illnesses that occurred after August 14, 2013, might not yet have been reported because of the time it takes between when a person becomes ill and when the illness is reported. This could take up to 5 to 6 weeks.

September 17, 2013

As of September 13, 2013 (5pm EDT), a total of 642 ill persons with Cyclospora infection have been reported from 25 states. Since the last update on September 10, 6 additional ill people were reported, but 10 cases were retracted because new information revealed that they did not meet the CDC outbreak case definition.

Ill persons range in age from less than one year to 92 years, with a median age of 52 years. Fifty-seven percent (57%) of ill persons are female. Among 578 ill persons for whom information is available, 45 (8%) have reported being hospitalized. No deaths have been reported.

Illnesses that occurred after August 7, 2013, might not yet have been reported because of the time it takes between when a person becomes ill and when the illness is reported. This could take up to 5 to 6 weeks.

September 10, 2013

Case Count Update

As of September 6, 2013 (5pm EDT), a total of 646 ill persons with Cyclospora infection have been reported from 24 states. Since the last update on September 4, 5 additional ill people were reported.

Ill persons range in age from less than one year to 92 years, with a median age of 52 years. Fifty-seven percent (57%) of ill persons are female. Among 575 ill persons for whom information is available, 44 (8%) have reported being hospitalized. No deaths have been reported.

Illnesses that occurred after July 31, 2013, might not yet have been reported because of the time it takes between when a person becomes ill and when the illness is reported. This could take up to 5 to 6 weeks.

September 4, 2013

Case Count Update

As of September 3, 2013 (5pm EDT), a total of 641 ill persons with Cyclospora infection have been reported from 24 states. Since the last update on August 30, 5 additional ill people were reported.

Ill persons range in age from less than one year to 92 years, with a median age of 51 years. Fifty-six percent (56%) of ill persons are female. Among 541 ill persons for whom information is available, 41 (8%) have reported being hospitalized. No deaths have been reported.

Illnesses that occurred after July 28, 2013, might not yet have been reported because of the time it takes between when a person becomes ill and when the illness is reported. This could take up to 5 to 6 weeks.

August 30, 2013

Case Count Update

As of August 29, 2013 (5pm EDT), a total of 636 ill persons with Cyclospora infection have been reported from 23 states. Since the last update on August 28, 20 additional ill people were reported.

Ill persons range in age from less than one year to 92 years, with a median age of 51 years. Fifty-five percent (55%) of ill persons are female. Among 591 ill persons for whom information is available, 45 (8%) have reported being hospitalized. No deaths have been reported.

Illnesses that occurred after July 24, 2013, might not yet have been reported because of the time it takes between when a person becomes ill and when the illness is reported. This could take up to 5 to 6 weeks.

August 28, 2013

Case Count Update

As of August 27, 2013 (5pm EDT), a total of 616 ill persons with Cyclospora infection have been reported from 22 states. Since the last update on August 26, 6 additional ill people were reported.

Ill persons range in age from less than one year to 92 years, with a median age of 51 years. Fifty-six percent (56%) of ill persons are female. Among 591 ill persons for whom information is available, 45 (8%) have reported being hospitalized. No deaths have been reported.

Illnesses that occurred after July 22, 2013, might not yet have been reported because of the time it takes between when a person becomes ill and when the illness is reported. This could take up to 5 to 6 weeks.

August 26, 2013

Investigation Update

Because many of the more recent cases have been reported from Texas, CDC is collaborating with the Texas Department of Health and Human Services and local public health departments to investigate cases of cyclosporiasis reported among people in Texas.

Public health investigators have interviewed ill people in Texas about their exposures during the 2 weeks before they became ill. These interviews have covered what food they ate and where they ate and purchased their food. On the basis of these interviews, investigators have identified a group (cluster) of ill people who reported eating at the same restaurant. A detailed investigation of this cluster is ongoing. This investigation includes listing the different ingredients in the food that was eaten. People who did not get sick but who also ate meals at the same restaurant on the same days as ill people are also being interviewed. The preliminary analysis of results from this ongoing cluster investigation in Texas does not show a connection to salad mix, leafy greens, and salad mix components produced at Taylor Farms de Mexico.

From August 11-19, 2013, FDA with the cooperation of Taylor Farms de Mexico and Mexican government authorities conducted a thorough environmental assessment at the firm’s processing facility. The team also assessed five farms identified through traceback information from the outbreak investigation. The team found that conditions and practices at these facilities at the time of the assessment were in accordance with known food safety protocols. On August 25, 2013, Taylor Farms de Mexico, with FDA concurrence, resumed production and shipment of salad mix, leafy greens, and salad mix components to the United States. The firm had voluntarily ceased production and shipment of these products on August 9, 2013.

The findings in Texas differ from those from earlier investigations in Iowa and Nebraska. In those states investigators linked cyclosporiasis cases acquired after eating in one of multiple restaurants to eating a bagged salad mix from Taylor Farms de Mexico. It is not unusual to recognize outbreaks that happen in the same season but are due to different foods. As in 2013 and in years past, most cases and outbreaks of cyclosporiasis in the United States are detected in spring and summer months. Not all cases during the same time of year are necessarily caused by the same exposure.

For example, during a several-month period in 1997, there were three separate and unrelated outbreaks of cyclosporiasis caused by different fresh produce items from various sources. Strong evidence from epidemiologic investigations led to the recognition that the outbreaks were separate and unrelated. Although the investigation of cases in 2013 is ongoing, available evidence suggests that not all of the cases of cyclosporiasis in the various states are directly related to each other. CDC continues to work with state and local partners and FDA to investigate clusters of illness, food exposures, and sources of food items.

Laboratory Update

Case Count Update

As of August 23, 2013 (5pm EDT), a total of 610 ill persons with Cyclospora infection have been reported from 22 states. Since the last update, 1 additional ill person was reported.

Ill persons range in age from less than one year to 92 years, with a median age of 51 years. 55 percent of ill persons are female. Among 581 ill persons for whom information is available, 43 (7%) have reported being hospitalized. No deaths have been reported.

Illnesses that occurred after July 17, 2013, might not yet have been reported because of the time it takes between when a person becomes ill and when the illness is reported. This could take up to 5 to 6 weeks.

August 23, 2013

Case Count Update

As of August 22, 2013 (5pm EDT), a total of 609 ill persons with Cyclospora infection have been reported from 22 states. Since the last update, 8 additional ill people were reported.

Ill persons range in age from less than one year to 92 years, with a median age of 51 years. 56 percent of ill persons are female. Among 471 ill persons for whom information is available, 40 (9%) have reported being hospitalized. No deaths have been reported.

Illnesses that occurred after July 16, 2013, might not yet have been reported because of the time it takes between when a person becomes ill and when the illness is reported. This could take up to 5 to 6 weeks.

August 22, 2013

Case Count Update

As of August 21, 2013 (5pm EDT), a total of 601 ill persons with Cyclospora infection have been reported from 22 states. Since the last update, 3 additional ill people were reported.

Ill persons range in age from less than one year to 92 years, with a median age of 51 years. 55 percent of ill persons are female. Among 465 ill persons for whom information is available, 40 (9%) have reported being hospitalized. No deaths have been reported.

Illnesses that occurred after July 15, 2013, might not yet have been reported because of the time it takes between when a person becomes ill and when the illness is reported. This could take up to 5 to 6 weeks.

August 21, 2013

Case Count Update

As of August 20, 2013 (5pm EDT), a total of 598 ill persons with Cyclospora infection have been reported from 22 states. Since the last update, 5 additional ill people were reported.

Ill persons range in age from less than one year to 92 years, with a median age of 51 years. 55 percent of ill persons are female. Among 456 ill persons for whom information is available, 40 (9%) have reported being hospitalized. No deaths have been reported.

Illnesses that occurred after July 14, 2013, might not yet have been reported because of the time it takes between when a person becomes ill and when the illness is reported. This could take up to 5 to 6 weeks.

August 20, 2013

Case Count Update

As of August 19, 2013 (5pm EDT), a total of 593 ill persons with Cyclospora infection have been reported from 20 states. Since the last update, 7 additional ill people were reported.

Ill persons range in age from less than one year to 92 years, with a median age of 51 years. 55 percent of ill persons are female. Among 423 ill persons for whom information is available, 36 (9%) have reported being hospitalized. No deaths have been reported.

Illnesses that occurred after July 13, 2013, might not yet have been reported because of the time it takes between when a person becomes ill and when the illness is reported. This could take up to 5 to 6 weeks.

August 19, 2013

Case Count Update

As of August 16, 2013 (5pm EDT), a total of 586 ill persons with Cyclospora infection have been reported from 20 states. Since the last update, 10 additional ill people were reported.

Ill persons range in age from less than one year to 92 years, with a median age of 51 years. Fifty-five percent of ill persons are female. Among 440 ill persons for whom information is available, 36 (8%) have reported being hospitalized. No deaths have been reported.

Illnesses that occurred after July 10, 2013, might not yet have been reported because of the time it takes between when a person becomes ill and when the illness is reported. This could take up to 4 to 5 weeks.

August 16, 2013

Case Count Update

As of August 15, 2013 (5pm EDT), a total of 576 ill persons with Cyclospora infection have been reported from 19 states. Since the last update, 19 additional ill people were reported.

Ill persons range in age from less than one year to 92 years, with a median age of 51 years. Fifty-four percent of ill persons are female. Among 423 ill persons for whom information is available, 36 (9%) have reported being hospitalized. No deaths have been reported.

Illnesses that occurred after July 9, 2013, might not yet have been reported because of the time it takes between when a person becomes ill and when the illness is reported. This could take up to 4 to 5 weeks.

August 15, 2013

Case Count Update

As of August 14, 2013 (5pm EDT), a total of 557 ill persons with Cyclospora infection have been reported from 19 states. Since the last update, nine additional ill people were reported.

Ill persons range in age from less than one year to 92 years, with a median age of 51 years. Fifty-four percent of ill persons are female. Among 422 ill persons for whom information is available, 35 (8%) have reported being hospitalized. No deaths have been reported.

Illnesses that occurred after July 6, 2013, might not yet have been reported because of the time it takes between when a person becomes ill and when the illness is reported. This could take up to 4 to 5 weeks.

August 14, 2013

Case Count Update

As of August 13, 2013 (5pm EDT), a total of 548 ill persons with Cyclospora infection have been reported from 19 states. Since the last update, nine additional ill people were reported.

Ill persons range in age from less than one year to 92 years, with a median age of 51 years. Fifty-five percent of ill persons are female. Among 418 ill persons for whom information is available, 34 (8%) have reported being hospitalized. No deaths have been reported.

Illnesses that occurred after July 6, 2013, might not yet have been reported because of the time it takes between when a person becomes ill and when the illness is reported. This could take up to 4 to 5 weeks.

August 13, 2013

Case Count Update

As of August 12, 2013 (5pm EDT), a total of 539 ill persons with Cyclospora infection have been reported from 19 states. Since the last update, four additional ill persons were reported. At least 32 people have reported being hospitalized. No deaths have been reported.

August 12, 2013

Case Count Update

As of August 9, 2013 (5pm EDT), a total of 535 ill persons with Cyclospora infection have been reported from 18 states. Since the last update, 21 additional ill persons were reported. At least 32 people have reported being hospitalized. No deaths have been reported.

Investigation Update

On August 12, 2013, Taylor Farms de Mexico officially informed FDA that, as of August 9, 2013, the company had voluntarily suspended production and shipment of any salad mix, leafy green, or salad mix components from its operations in Mexico to the United States. FDA reported that the firm has committed to not resume production and shipping of these products from its operations in Mexico without FDA's approval.

August 8, 2013

Case Count Update

As of August 7, 2013 (5pm EDT), a total of 504 ill persons with Cyclospora infection have been reported from 17 states. Since the last update, 37 additional ill persons were reported. At least 30 people have reported being hospitalized. No deaths have been reported.

August 7, 2013

Case Count Update

As of August 6, 2013 (5pm EDT), a total of 467 ill persons with Cyclospora infection have been reported from 16 states. Since the last update, one additional ill person was reported. At least 27 people have reported being hospitalized. No deaths have been reported.

August 6, 2013

Case Count Update

As of August 5, 2013 (5pm EDT), a total of 466 ill persons with Cyclospora infection have been reported from 16 states. Since the last update, 41 additional ill persons were reported. At least 27 people have reported being hospitalized. No deaths have been reported.

August 5, 2013

Case Count Update

As of August 2, 2013 (5pm EDT), a total of 425 ill persons with Cyclospora infection have been reported from 16 states. Since the last update, 25 additional ill persons were reported. At least 24 people have reported being hospitalized. No deaths have been reported.

August 2, 2013

Case Count Update

As of August 1, 2013 (5pm EDT), a total of 400 ill persons with Cyclospora infection have been reported from 17 states. Since the last update, two additional ill persons were reported. At least 22 people have reported being hospitalized. No deaths have been reported.

Investigation Update

On July 30, 2013, the states of Iowa and Nebraska announced that their analysis indicated that the outbreak in those states was linked to a salad mix. In follow-up to that announcement, the U.S. Food and Drug Administration provided an update on its investigation.

According to FDA, a traceback investigation confirmed that the salad mix identified by Iowa and Nebraska as being linked to the outbreak of cyclosporiasis in those states was supplied to restaurants in those states by Taylor Farms de Mexico, S. de R.L. de C.V., a processor of foodservice salads—i.e., the salad mix associated with illness clusters at restaurants in these two states was from a common supplier (Taylor Farms de Mexico, S. de R.L. de C.V.). According to FDA, the restaurants in Iowa and Nebraska include Olive Garden and Red Lobster, both of which are owned by Darden Restaurants.

August 1, 2013

Case Count Update

As of July 31, 2013 (5pm EDT), a total of 398 ill persons with Cyclospora infection have been reported from 18 states. Since the last update, 20 additional ill persons were reported. At least 22 people have reported being hospitalized. No deaths have been reported.

July 31, 2013

Case Count Update

As of July 30, 2013 (5pm EDT), a total of 378 ill persons with Cyclospora infection have been reported from 16 states. Since the last update, 6 additional ill persons were reported. At least 21 people have reported being hospitalized. No deaths have been reported.

July 30, 2013

Case Count Update

As of July 29, 2013 (5pm EDT), a total of 372 ill persons with Cyclospora infection have been reported from 16 states. Since the last update, 19 additional ill persons were reported. At least 21 people have reported being hospitalized. No deaths have been reported.

July 29, 2013

Case Count Update

As of July 28, 2013 (5pm EDT), a total of 353 ill persons with Cyclospora infection have been reported from 15 states. Since the last update, 32 additional ill persons were reported. At least 21 people have reported being hospitalized. No deaths have been reported.

July 26, 2013

Case Count Update

As of July 25, 2013 (5pm EDT), CDC has been notified of a total of 321 ill persons with Cyclospora infection in residents of multiple states, including Arkansas, Connecticut, Florida, Georgia, Iowa, Minnesota, Missouri, Nebraska, New Jersey, New York, including New York City, Ohio, Texas, and Wisconsin. Illinois and Kansas have also notified CDC of one ill person each that may have acquired illness out of state but in the United States. At least 18 people have reported being hospitalized. No deaths have been reported.

July 25, 2013

Case Count Update

As of July 24, 2013 (5pm EDT), CDC has been notified of a total of 284 ill persons with Cyclospora infection in residents of multiple states, including Connecticut, Georgia, Iowa, Minnesota, Nebraska, New Jersey, Ohio, Texas, and Wisconsin. Illinois and Kansas have also notified CDC of one ill person each that may have acquired illness out of state but in the United States. At least 18 people have reported being hospitalized. No deaths have been reported.

July 24, 2013

Case Count Update

As of July 23, 2013 (5pm EDT), CDC has been notified of more than 275 ill persons with Cyclospora infection in residents of multiple states, including Connecticut, Georgia, Iowa, Nebraska, New Jersey, Texas, and Wisconsin. Illinois and Kansas have also notified CDC of one ill person each that may have acquired illness out of state but in the United States. At least 10 people have reported being hospitalized. No deaths have been reported.

July 23, 2013

Case Count Update

As of July 22, 2013 (5pm EDT), CDC has been notified of more than 250 ill persons with Cyclospora infection in residents of multiple states, including Connecticut, Georgia, Iowa, Nebraska, Texas, and Wisconsin. Illinois and Kansas have also notified CDC of one ill person each that may have acquired illness out of state but in the United States. At least 10 people have reported being hospitalized. No deaths have been reported.

July 22, 2013

On June 28, 2013, CDC was notified of 2 laboratory-confirmed cases of Cyclospora infection in Iowa residents who had become ill in June and did not have a history of international travel during the 14 days before the onset of illness. Since that date, CDC has been collaborating with public health officials in multiple states and the U.S. Food and Drug Administration (FDA) to investigate an outbreak of cyclosporiasis.

As of July 18, 2013 (5pm EDT), CDC has been notified of more than 200 ill persons with Cyclospora infection in residents of multiple states, including Iowa, Nebraska, Texas, and Wisconsin. Illinois has also notified CDC of one ill person each that may have acquired illness out of state. It is not yet clear whether the ill persons from all of the states are part of the same outbreak. Most of the illness onset dates have ranged from mid-June through early July. At least eight people have reported being hospitalized. No deaths have been reported.

No food items have been implicated to date, but public health authorities are pursing all leads. No common events (e.g., social gatherings) have been identified among the ill persons. Previous Cyclospora foodborne outbreak investigations have implicated various types of fresh produce.