June 2011

The Alaska Department of Health and Social Services is investigating four cases of people who became sick after drinking bacteria-contaminated raw milk from a Mat-Su Valley farm.

According to DHSS spokesperson Greg Wilkinson, state law doesn’t allow the sale of raw milk, but does permit owning shares of an animal to receive its milk — which doesn’t have to be tested or pasteurized before it’s distributed.

The four people infected with Campylobacter jejuni bacteria from May 7 through June 4 were Southcentral Alaska residents ranging in age from 1 to 81 years old. All four experienced severe stomach flu after drinking raw milk from one of the unnamed farm’s cows, and two said family members also experienced symptoms but did not seek medical attention.

Staff with the state Department of Conservation’s Division of Environmental Health visited the farm in May to evaluate sanitary conditions and pick up a bulk milk tank for testing. The sample tested negative for Campylobacter but positive for Listeria monocytogenes, a foodborne pathogen that can cause life-threatening infections in newborns and adults.

Officials believe the month-long pattern of cases points to a series of contamination events rather than a single bad batch, which is possible given the rich nutrients contained in milk.

“Raw milk is an ideal substance for the proliferation of bacteria introduced through fecal contamination,” said Dr. Joe McLaughlin, chief of the DHSS Section of Epidemiology. “Unpasteurized milk can be infected with a number of pathogens including Listeria, Salmonella, and as we’ve seen in this case, Campylobacter.”

A fact sheet on Listeria was distributed to the 1,100 shareholders in the farm’s cow-share program following DEC’s May visit. Test results from a June 22 follow-up visit by DEC and DHSS personnel are still pending.

Screen shot 2011-06-17 at 3.13.32 PM.pngLaboratory test results show that the Campylobactor jejuni bacteria that caused diarrheal illness among 16 individuals who drank unpasteurized (raw) milk at a school event early this month in Raymond was the same bacteria strain found in unpasteurized milk produced at a local farm, according to officials from the Department of Health Services (DHS) and Western Racine County Health Department (WRCHD). A parent had supplied unpasteurized milk from the farm for the school event.

Stool samples submitted to the WRCHD by ill students and adults were sent to the State Laboratory of Hygiene where they tested positive for the bacteria. Department of Agriculture, Trade and Consumer Protection (DATCP) food inspectors collected milk samples from the bulk tank at the farm, which tested positive for Campylobacter jejuni. Further testing by the State Hygiene lab showed the bacteria strain from the stool samples and the milk samples matched. Additionally, interviews with event attendees revealed that consuming the unpasteurized milk was statistically associated with illness. Health officials said that this combination of laboratory and epidemiologic evidence indicates that the illnesses were caused by the unpasteurized milk consumed at the school event.

Campylobacter jejuni bacteria can cause diarrhea, which can be bloody, abdominal cramping, fever, nausea and vomiting. Rarely, an infection may lead to paralysis after initial symptoms have disappeared. Campylobacter can be transmitted by consuming food contaminated directly or indirectly by animal feces or handled by someone with the infection who has not adequately washed hands after using the bathroom

The farm did not sell the unpasteurized milk and there was no legal violation associated with the milk being brought to the school event. The farm is licensed and in good standing with the Department of Agriculture, Trade and Consumer Protection.

Gardner TJ, Fitzgerald C, Xavier C, Klein R, Pruckler J, Stroika S, McLaughlin JB.  Epidemic Intelligence Service, Office of Workforce and Career Development, Centers for Disease Control and Prevention, Atlanta, Georgia.

Screen shot 2011-06-12 at 8.45.36 PM.pngAbstract

Background. Campylobacter jejuni is a leading cause of acute gastroenteritis worldwide, and most cases are identified as sporadic events rather than as parts of recognized outbreaks. We report findings from a substantial 2008 campylobacteriosis outbreak with general implications for fresh produce safety.

Methods. We conducted a matched case-control study to determine the source of the outbreak and enhanced surveillance to identify additional cases. Clinical and environmental specimens were tested for Campylobacter, and isolates were subtyped by pulsed-field gel electrophoresis (PFGE).

Results. By routine surveillance, we identified 63 cases of laboratory-confirmed infection. Only raw peas, consumed by 30 (67%) of 45 case-patients and by 15 (17%) of 90 control participants, were associated with illness (adjusted odds ratio: 8.2; P < .001). An additional 69 patients (26 laboratory-confirmed) who reported eating raw peas within 10 days of illness onset were identified through enhanced surveillance. In all, 5 cases were hospitalized, and Guillain-Barré syndrome developed in 1 case; none died. The implicated pea farm was located near a Sandhill crane (Grus canadensis) stopover and breeding site. Of 36 environmental samples collected, 16 were positive for C. jejuni-14 crane-feces samples and 2 pea samples. We identified 25 unique combined SmaI-KpnI PFGE patterns among clinical isolates; 4 of these combined PFGE patterns identified in 15 of 55 human isolates were indistinguishable from PFGE patterns identified in environmental samples.

Conclusions. This investigation established a rare laboratory-confirmed link between a campylobacterosis outbreak and an environmental source and identified wild birds as an underrecognized source of produce contamination.