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C. jejuni – an ever-present and often forgotten bacteria

Vet Advice with Dr. Ron Clarke

Campylobacter jejuni (CAMP-EE-LO-BACK-TER JE-JUNE-EYE) is the most common cause of bacterial diarrhea in the North America, causing an estimated 1.5 million human diarrheal illnesses annually. Infections are common in young children, and young adults between the ages of 18 to 29. Asymptomatic human carriers are rare.

Most human cases are caused through contact with animals shedding C. jejuni. Consumption of contaminated or undercooked meat and poultry, unpasteurized milk or dairy products, untreated water and unwashed vegetables are major routes of transmission in humans. People can also be infected by direct contact with infected animals or feces. Producers and their families working with newborn animals exhibiting signs of diarrhea during calving and lambing season are particularly at risk.

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Campylobacter jejuni is found worldwide in the intestinal tracts of animals. Cattle, sheep, dogs and poultry are common carriers, but C. jejuni also occurs in a wide spectrum of animals including turkeys, cats, mink, pigs, and non-human primates.

Asymptomatic (non-clinical) carriers that shed organisms without showing signs of disease are common in animals. Most cases of campylobacteriosis (the disease caused by C. jejuni) are associated with handling or eating raw or undercooked poultry meat. Poultry, particularly broiler chickens, are an especially important source of the bacterium. Numerous strategies have been tried to decrease colonization of C. jejuni in poultry, but none have proven to be successful in reducing prevalence in broiler flocks.

Campylobacteriosis causes gastrointestinal symptoms, such as diarrhea, cramping, abdominal pain, and fever in both domestic animals and humans. Young animals and humans are most severely affected.

Diarrhea caused by C. jejuni and a closely related species, C. coli, is usually self-limiting and generally resolves after seven to10 days. Signs in humans range from mild to severe. Relapses can occur in approximately 10 to 25 per cent of cases. Immunosuppressed individuals are at a high risk for severe or recurrent infections. Generalized infection (septicemia) can occur in patients with other debilitating diseases. Deaths are rare in C. jejuni infections and are seen mainly in patients with other chronic diseases.

C. jejuni is a major triggering event for Guillain-Barré syndrome, a serious neurological condition seen after approximately one in 1,000 diagnosed infections. Up to five percent of Guillain-Barré patients may die, and 30 per cent or more recover with residual weakness or other neurologic defects.

Another species in the campylobacter family of disease agents, C. fetus, (the organism previously known as vibrio) is a common cause of reproductive disease in sheep and cattle.

Antibiotic resistance in campylobacter species is a serious problem worldwide, particularly for the broad-spectrum antimicrobials: fluoroquinolones and tetracyclines.

Fecal-oral transmission of C. jejuni and C. coli is common. Contaminated or undercooked meats are sources of infection for carnivores such as pets and commercially raised mink. C. jejuni can be found in the vaginal discharges, aborted fetuses and fetal membranes of aborting sheep. Wild rodents and insects like houseflies act as mechanical vectors.

Campylobacter species do not tolerate drying or heating, but survive for sustained periods in moist environments. Campylobacter survives for weeks in water at 4 C (39 F). C. jejuni remains viable for up to nine days in feces and three days in milk. C. jejuni and C. coli remain infective in moist poultry litter for prolonged periods.

Campylobacter spp. can spread person- to-person, a common problem reported with young children suffering from diarrhea at daycare centres. C. jejuni can be shed in feces for as long as two to seven weeks if untreated.

The incubation period for campylobacter infections is generally short. Signs of enteritis and abdominal discomfort appear within three days after contact with the organism. Clinical signs are often most severe in young animals. Feces are usually watery or bile-streaked, with mucus and sometimes blood. Animals may or may not have a fever.

C. jejuni has recently become the predominant cause of sheep abortion and can be confused with late-term abortions, stillbirths and weak lambs caused by C. fetus. Infections in sheep are not uncommonly followed by metritis (uterine infections) and occasionally deaths. Recovery, with immunity to reinfection, is typical.

Studies have shown that the prevalence of C. jejuni increases through the feeding period in feedlots. In one study, C. jejuni prevalence increased from just over one per cent at the first sampling to over 60 per cent prior to slaughter. Chlorination of water troughs had no effect. The results demonstrate an apparent transmission of C. jejuni among feedlot cattle during the feeding period, resulting in a high prevalence of C. jejuni excretion by cattle approaching slaughter.

C. jejuni has also been reported as a cause of abortion storms on western Canadian ranches through the 1990s. Abortions, accompanied by placental retention and weight loss, occurred during February and March in 19 per cent of 120 and 10 per cent of 108 beef cows and heifers on two neighbouring ranches in southern Saskatchewan. A diagnosis of C. jejuni abortion was made based on placental and fetal lesions in association with the culture of large numbers of C. jejuni from placentas and fetal tissues. The source and mode of transmission of C. jejuni was thought to be fecal contamination of water supplies and feeding grounds by carrier cows or wildlife.

The industry needs to be aware that C. jejuni exists within most herds and feedlots. For the most part it exists as a silent threat to both animal and human health. The reality is that cattle carcasses could be contaminated at slaughter. Contamination of retail meat samples has been reported. There are few specific preventive measures for preventing C. jejuni. Good hygiene through implementation of sound biosecurity measures and appropriate husbandry practices is recommended. Specific measures include insect and rodent control at a minimum, plus use of strategically placed footbaths when weather permits. Avoidance of stress, and overcrowding, may decrease shedding by carriers. Cross-contamination can be lessened by regular cleaning and decontamination of transport vehicles.

About the author

Columnist

Dr. Ron Clarke prepares this column on behalf of the Western Canadian Association of Bovine Practitioners. Suggestions for future articles can be sent to Canadian Cattlemen ([email protected]) or WCABP ([email protected]).

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