Outbreak Investigation Updates by Date
Final Update
Published June 21, 2019 at 3:00 PM ET
This outbreak appears to be over. Consumers, restaurants, and retailers should always handle and cook oysters properly. Get CDC’s tips for preventing foodborne illness from oysters and other shellfish.
May 22, 2019
Since the last update on May 10, 2019, one ill person was added to this outbreak. Another ill person was excluded from this outbreak because additional laboratory evidence did not support a link to raw oysters harvested from Estero El Cardon.
As of May 22, 2019, 16 ill people have been reported from five states. Ill people in this outbreak have been infected with multiple pathogens causing illness, including Vibrio parahaemolyticus, Shigella flexneri, STEC non-O157, Vibrio albensis, Campylobacter lari, and norovirus genogroup 1.
Illnesses started on dates ranging from December 16, 2018 to April 17, 2019. Among 15 people with information available, ages range from 26 to 80 years, with a median age of 38. Sixty percent are male. Of 15 people with clinical information available, 2 (13%) hospitalizations were reported.
A list of the states reporting people linked to the outbreak and the number of cases in each state can be found on the Map of Reported Cases page.
State health officials have reported two additional ill people to CDC who are not included in the number of cases linked to the outbreak. These people did not consume raw oysters but they did have contact with one of the people in the outbreak with a Shigella flexneri infection. Shigella spreads easily from one person to another. See prevention tips.
Illnesses that occurred after April 17, 2019, might not yet be reported due to the time it takes between when a person becomes ill and when the illness is reported. This can take 4 or more weeks.
Investigation of the Outbreak
CDC, public health and regulatory officials in several states, and the U.S. Food and Drug Administration (FDA) are investigating illnesses linked to raw oysters harvested from Estero El Cardon estuary in Baja California Sur, Mexico. This multistate investigation began on March 29, 2019, when the PulseNet system identified a cluster of closely related Vibrio parahaemolyticus bacteria in samples isolated from ill people. Epidemiologic and traceback evidence indicated that people ate raw oysters harvested from Estero El Cardon (an estuary) in Baja California Sur, Mexico. State public health officials identified additional illnesses among people who also ate raw oysters from the same harvest area. FDA is investigating a subset of illnesses currently being investigated by the CDC.
In interviews, ill people answered questions about the foods they ate and other exposures in the week before they became ill. All 15 people who were interviewed reported eating raw oysters from different restaurants in California and Nevada. State health officials collected traceback information for 15 cases and found that oysters were shipped by Sol Azul, S.A. de C.V. (MX 01 SS) and harvested from Estero El Cardon. These oysters were distributed to California, Nevada, New York, and Arizona. It is possible that additional states received these oysters either directly from Mexico or through further distribution within the United States. Oysters were sold to wholesale distributors with direct sales to restaurants. The oysters were not sold to grocery retail outlets.
On May 6, one U.S. distributor of oysters harvested from Estero El Cardon issued a voluntary recall pdf icon[PDF – 197 KB].external icon On May 7, Estero El Cardon was closed to further oyster harvesting pdf icon[PDF – 491 KB]external icon pending investigation. At the request of Mexico’s public health authorities, all raw oysters distributed from the last week of April through the first week of May have been recalled. FDA continues to work with Mexico’s health authorities, and state and local partners continue to verify that this product has been successfully removed from commerce and to ensure that the raw oysters were not further distributed. For more information, see the Mexico recall notice. pdf icon[PDF – 474 KB]external icon
This investigation is ongoing. CDC will provide updates when more information is available.
May 10, 2019
CDC and public health and regulatory officials in several states are investigating a multistate outbreak of gastrointestinal illnesses linked to raw oysters harvested from Estero El Cardon estuary in Baja California Sur, Mexico. On May 6, one U.S. distributor of oysters harvested from Estero El Cardon issued a voluntary recall. pdf icon[PDF – 197 KB]external icon On May 7, Estero El Cardon was closed to further oyster harvesting pdf icon[PDF – 491 KB]external icon pending investigation.
Public health investigators are using the PulseNet system and epidemiologic and traceback evidence to identify illnesses that may be part of this outbreak. PulseNet is the national subtyping network of public health and food regulatory agency laboratories coordinated by CDC. Whole genome sequencing (WGS) is a technique for DNA fingerprinting that is performed on bacteria isolated from ill people. CDC PulseNet manages a national database of these DNA fingerprints to identify possible outbreaks. WGS performed on three Vibrio parahaemolyticus bacteria samples isolated from ill people showed that they were closely related genetically. WGS shows that five Shigella flexneri bacteria samples isolated from ill people are also closely related genetically. Illnesses caused by bacteria that are closely related are more likely to share a common source of infection.
Epidemiologic and traceback evidence for these cases indicated people ate raw oysters harvested from Estero El Cardon in Baja California Sur, Mexico. State public health officials identified additional illnesses among people who also ate raw oysters from the same harvest area.
As of May 10, 2019, 16 ill people have been reported from five states. Ill people in this outbreak have been infected with multiple pathogens causing illness, including Vibrio parahaemolyticus, Shigella flexneri, STEC non-O157, Vibrio albensis, Campylobacter lari, and norovirus genogroup 1.
In interviews, ill people answered questions about the foods they ate and other exposures in the week before they became ill. All 15 people who were interviewed reported eating raw oysters from different restaurants in California and Nevada. State health officials collected traceback information for 15 cases and found that oysters were shipped by SOL AZUL, S.A. DE C.V. (MX 01 SS) and harvested from Estero El Cardon (an estuary).
Illnesses started on dates ranging from December 16, 2018 to April 4, 2019. Among 15 people with information available, ages range from 26 to 80 years, with a median age of 38. Sixty-seven percent are male. Of 15 people with clinical information available, 2 (13%) hospitalizations were reported.
A list of the states reporting people linked to the outbreak and the number of cases in each state can be found on the Map of Reported Cases page.
Illnesses might not yet be reported due to the time it takes between when a person becomes ill and when the illness is reported. This can take 4 or more weeks.
This investigation is ongoing. CDC will provide updates when more information is available.