The following information updates our letter of August 22, 2008:
- Expansions of the list of recalled items;
- Anticipated increase in reporting of cases with continued encouragement to have a higher than usual index of suspicion for listeriosis especially among patients at higher risk and with a history of eating Maple Leaf meats or other recall products in the past few months (incubation ranges from 3-70 days with a median of 3 weeks);
- Confirmation that concern about the Listeria outbreak is NOT a reason to discontinue or question breastfeeding;
- Information on laboratory support and appropriate selection of laboratory tests when listeriosis is in your differential diagnosis; and
- Revision to high risk populations to include iron overload disorders such as hemochromatosis.
Expansion to the recalled items
The recall of products was voluntarily expanded to include all products from the Maple Leaf plant in which the contaminated products were prepared. This was a precautionary move. To date, only products from the single processing plant are included. These products are identified by the number 97B near the ‘best before’ date or ‘packaged’ date. The full list of recalled products and pictures showing the production plant 97B code are easy to access on the Fraser Health website: www.fraserhealth.ca (click on the Listeriosis Outbreak box) or at the Canadian Food Inspection Agency (CFIA) site: www.inspection.gc.ca/english/corpaffr/recarapp/recaltoce.shtml A coordinated strategy has dealt with distributors and chain stores. Fraser Health has worked as part of the coordinated team of several agencies to ensure that, for the initial and expanded recalls, implicated products have been removed from facilities in the region including hospitals, adult and child care facilities, assisted living residences, public and independent schools and post-secondary institutions in which the products may have been provided or sold.
The current outbreak
Frequent updates are posted on the Public Health Agency of Canada (PHAC) website: http://www.phac-aspc.gc.ca/index-eng.php This is easily accessed from the Fraser Health website www.fraserhealth.ca and has links to Question & Answer documents, BC Healthfiles on Listeria and a household resource on Listeria and Food Safety that includes advice to individuals at higher risk of serious illness regarding Foods to Avoid and Safer Alternatives. As of August 27th, there were 29 confirmed cases of the outbreak strain of Listeria (4 of which are in BC) and 31 suspect cases (none currently in BC) that are under investigation to determine if they are linked with the outbreak or not. The number of cases is clearly expected to rise, given the wide distribution of products and the long and variable incubation period (3 to 70 days with an estimated median of 3 weeks). There were 15 deaths (12 in Ontario and 1 in each of BC, Saskatchewan and Quebec). Of the 15 deaths, 5 (all in Ontario) have had Listeriosis linked as the underlying or a contributing cause of death. In the remaining deaths, the role of Listeria remains under investigation.
Concern about the Listeria outbreak is NOT a reason to discontinue or question breastfeeding
With coverage of the expanded recall, a local TV news report may have, inadvertently, raised concerns about breastfeeding by mothers who think they might have eaten something with contaminated product. The Listeria outbreak is definitely NOT an indication to stop breastfeeding, even if a mother is infected. Indeed, breast-fed infants are less likely to experience gastrointestinal infections of any type than infants who are not breast-fed. Please reassure any nursing mothers with questions about the Listeria outbreak that the clear public health recommendation is to continue breastfeeding.
Diagnostic support for suspect Listeriosis (adapted from guidance provided by Medical Microbiology at BC Centre for Disease Control Laboratory Services and Fraser Health)
Listeriosis can manifest itself differently, and in different susceptible populations.
For calls from concerned patients (general or high risk population) with no clinical illness, no clear history of exposure to implicated product, but worried that it might have been in something they ate:
For calls from concerned patients (general or high risk population) with no clinical illness, but have history of exposure to recalled product:
For patients presenting only with acute diarrhea:
For patients presenting with a febrile gastroenteritis (fever and diarrhea with or without abdominal cramps, nausea, vomiting, and headaches):
When the patient’s results for routine enteric work up (e.g., for Salmonella, Shigella, etc.) are negative; AND
The patient is susceptible to listeriosis (pregnant, immune compromised, immune suppressed, iron overload disorder or elderly > 65yo ); AND
The patient has consumed the implicated food products; a fresh stool sample may be forwarded to your local microbiology laboratory, which will then forward the samples to the BCCDC Laboratory for testing. The same specimen collection kit is used as for routine stool cultures (no preservative). Please mark on the requisition that testing is “Listeria Outbreak-related" and provide as much information as possible on the requisition to minimize follow-up calls from the Medical Microbiologists or local laboratories.
NOTE: If there is a level of severity such that greater urgency for Listeria testing is needed, prompt review with a Medical Microbiologist is recommended in order to facilitate testing for Listeria on the initial specimen, if indicated, and to consult on timing for any recommended intervention that may be indicated.
For the following patient groups, recommended workup will include blood cultures, CSF gram stain and cultures (if indicated) and/or meconium/amniotic fluid (if indicated) regardless of recalled product consumption. The media used are appropriate for Listeria. Consequently, stool for culture is not required:
PREGNANCY: Listeria infection in pregnancy may result in spontaneous abortion or stillbirth. It most commonly presents as an acute febrile illness, often accompanied by myalgia and arthralgia (‘flu-like’ illness), with or without headache and backache. Diarrhea alone is rare.
NEONATES with sepsis and/or meningitis;
Undiagnosed FEBRILE ILLNESS; or
Signs/symptoms consistent with MENINGITIS.
Food samples: BCCDC does not recommend testing of the implicated Maple Leaf food products, and the BCCDC Laboratory will not accept food items from patients for testing.The public health recommendation is to discard or return the food items to the retailer. The reasoning is that testing food is not necessarily reliable. A negative result does not mean that Listeria was not present in the portion that was consumed. A positive result does not add to the current knowledge that some Maple Leaf products have been contaminated with listeria of a very unique profile that are identical to those recovered from patients affected. The key is to identify patients who are at risk for having listeriosis and make sure they are appropriately investigated and managed in a timely manner.
Antibody Testing: There is no role for Listeria antibody testing.
Diagnostic and treatment guidance will be further discussed on a Provincial call this Friday. If there are any changes to the above recommendations, a follow-up letter will be sent to you promptly.
Revision to high risk populations to include iron overload disorders such as hemochromatosis
Those at most risk from serious illness due to Listeria include:
Pregnant women and their unborn or newborn children;
Older adults;
People with compromised immune systems such as those undergoing chemotherapy, transplant patients, those with HIV, diabetics and alcoholics; and
People with iron overload disorders such as hemochromatosis.
Thank you for your ongoing attention to this emerging outbreak and its potential to include cases in our region.
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