Campylobacter Blog - Surveillance & analysis on Campylobacter news & outbreaks

Over at Outbreak Database, we have been keeping track of foodborne illness outbreaks – small and large – over the last 12 months.  Here are some of the more interesting Campylobacter Outbreaks:

Jerry Dell Farm Unpasteurized, Raw Milk September 2011 – 2 Ill.  At least two people became ill due to Campylobacteriosis after drinking raw milk. Jerry Dell Farm in Freeville, New York had produced the milk. The farm had an agricultural permit to sell raw milk at the farm. The milk was confirmed to be contaminated with Campylobacter.

Matanuska-Suisitna Valley Cow Share Program Raw Milk May 2011 – 18 Ill.  An outbreak of Campylobacter jejuni was linked to the consumption of raw milk obtained through a cow share program in southeast Alaska. In Alaska, regulations did not allow the sale of raw milk; however owning shares of a cow to obtain milk was permissible. Campylobacter was not isolated from milk, but was isolated from manure samples collected at the dairy farm. Coincidentally Listeria was isolated, but no human illness had been attributed to this pathogen.

Last month, an outbreak of Salmonella that sickened at least 170 was tied to chicken liverin the U.S.  In the UK, health officials are issuing advisories linked to chicken liver pate, although out of fear of campylobacter infection.

The Wealden District Health Council, Sussex, has "stepped up checks on local restaurants to ensure chicken livers are being properly cooked before being made into paté," according to a report.

The Council's action followed a broader warning from  the Food Standards Agency reminding people to cook chicken livers thoroughly when making paté because of the risk of Campylobacter infection.  Campylobacter is the most common cause of food poisoning in the UK.

Proper cooking and misleading labeling appeared to be the problem as well.  It appears that consumers believed the chicken livers to be fully cooked, but they were not.

On June 27, 2011, the Alaska Section of Epidemiology (SOE) released an Epidemiology Bulletin detailing an outbreak of campylobacteriosis associated with the consumption of raw milk from Farm A in the Mat-Su Valley.1 This follow-up Bulletin provides updated information about the investigation.

Active Case finding

On June 24, SOE distributed an Advisory through the Public Health Alert Network (PHAN) to alert health care providers of the outbreak and to recommend testing for Campylobacter in patients who present with acute gastrointestinal (GI) illness and a history of raw milk consumption. Through the PHAN, the June 27 Bulletin, and associated press releases, members of the public were also asked to contact SOE and report acute GI illness following consumption of raw milk. SOE received calls from five community members reporting current and previous GI illness among persons in their households with a preceding history of consuming Farm A raw milk or cream. Public health nurses facilitated collection of stool specimens from recently ill persons for enteric bacterial pathogen testing at the Alaska State Public Health Laboratory (ASPHL).

Stool specimens were collected from six persons with recent GI illness and consumption of Farm A raw dairy products. Three of the six samples tested positive for Campylobacter jejuni; all isolates were the same rare strain of C. jejuni found in the four other laboratory-confirmed cases in this outbreak (pulsed-field gel electrophoresis [PFGE] pattern AKDBRS16.0166/AKDBRK02.0093). These three persons shared raw dairy products obtained from Farm A during the first week of July. A total of 11 persons who reported acute GI illness with routine consumption of Farm A dairy products but were not-laboratory confirmed were considered to have suspected campylobacteriosis (Figure).

Farm A bulk tank milk samples collected on June 22 and 27 tested negative for C. jejuni, but positive for Listeria monocytogenes. None of the Farm A raw milk that was actually consumed by ill persons was available for testing.

Discussion

The identical rare strain of C. jejuni has been identified in all laboratory-confirmed patients associated with this outbreak and Farm A cow manure specimens. These laboratory findings combined with the epidemiologic finding that Farm A raw dairy product consumption is the only exposure common to all seven laboratory-confirmed cases (and the 11 suspect cases) affirms the conclusion that this outbreak is due to consumption of Farm A raw dairy products. Contamination might have resulted from introduction of manure into the milk or cream at some point in time from milking to filling the containers, or a cow (or cows) with an infected udder may be intermittently shedding Campylobacter directly into the milk. Regardless of the exact mechanism of contamination, with confirmed cases reporting consumption of dairy products over an 8-week period from May to July, this outbreak poses an ongoing threat to Farm A raw dairy product consumers.

It is not surprising that C. jejuni was not detected in Farm A bulk tank samples because C. jejuni is notoriously difficult to culture from environmental specimens other than raw stool,2 and few campylobacteriosis outbreak investigations yield laboratory confirmation of an implicated food source such as raw milk or produce.3 Furthermore, none of the raw milk that was actually consumed by ill persons prior to their illness onset was available for testing. Numerous C. jejuni strains were detected on Farm A, which was anticipated given that many farm animals are known reservoirs for the bacteria. Finding only a single or predominant strain shared by the human cases is not unusual, and might relate to factors associated with seasonality or adaptation of the strain to humans.4 Finally, as was the case in May, the Farm A raw milk samples collected in June tested positive for L. monocytogenes, which can cause life-threatening meningitis in children and persons with compromised immune systems.

Environmental and Milk Testing Results

Eleven composite cow manure samples, one composite chicken manure sample, and one swab from the milking parlor drain were collected on June 22. ASPHL cultured the samples with guidance from the Centers for Disease Control and Prevention (CDC) Campylobacter Laboratory. Any culture suspicious for Campylobacter growth had up to six colonies chosen and plated for identification. From the 13 samples collected at the farm and submitted for culture, 18 separate colonies were identified as C. jejuni and underwent PFGE analysis; seven different PFGE patterns were identified. PFGE pattern AKDBRS16.0166/AKDBRK02.0093 was isolated in manure samples from the grazing field and the calf barn; this pattern was identical to the pattern of the C. jejuni isolated from the seven laboratory-confirmed patients.

Health authorities in Wyoming and Yuma County, AZ are reporting sharp increases in the number of Campylobacter infections and, in the case of Yuma County, possibly related increases of Guillain-Barré syndrome (GBS).

Campylobacter is a common diarrheal infection that is caused by ingesting fecal bacteria, often from contaminated food or water but also from exposure to farm animals and certain pets. The illness "can be extremely unpleasant," a Wyoming health official noted, but it can also lead to a life-threatening complication.

In some cases infected people develop GBS, in which the immune system attacks the body's nerves. It can cause paralysis and usually requires intensive care. The Centers for Disease Control and Prevention (CDC) estimates that about 40 percent of GBS disorders are preceded by a Campylobacter infection.

The Wyoming Department of Health said it has identified 29 cases of Campylobacter infections since June 1, a four-fold increase compared with the number typically reported during the same time period. At least six people have been hospitalized.

"While the increase in these infections appears to be sporadic with no single common source, it's clear than animal-related illness is at least partially driving the increase," said Kelly Weidenbach, a health department epidemiologist, in a news release.

Most of the case patients interviewed so far had contact with animals, especially cattle and dogs, and in many cases the animals were noted to be ill with diarrhea. Several case patients were ranchers or others who had recently attended a cattle branding, Weidenbach said.

According to a report in the Yuma Sun, health authorities there and across the border in San Luis Rio Colorado, Sonora, have reported an increase in Campylobacter infections and cases of GBS over the past three months.

As of July, there have been six confirmed and one suspected cases of GBS. The Yuma Sun said a June 18 article in Tribuna de San Luis reported 15 cases of GBS there.

The Yuma County Health District said it is working with the Arizona Department of Health Services, the CDC and Sonora health officials to determine the source of the outbreak. "An investigation of this nature takes a lot of time and a lot of people. It's like putting a puzzle together. You need all the pieces before you see the picture," said health district director Becky Brooks in a news release.

Laboratory 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.