| Campylobacteriosis is a significant enterocolitis of man acquired through consumption of undercooked poultry meat contaminated with Campylobacter jejuni . This organism colonizes the intestine of chickens, turkeys, and waterfowl but is generally nonpathogenic in mature poultry. Toxigenic and invasive strains of C jejuni can cause enteritis and death in newly hatched chicks and poults. It is not possible to satisfy Koch's postulates or reproduce the syndrome previously termed “avian vibrionic hepatitis” by administering isolates of C jejuni to chickens. Commercial poultry and free-living birds are natural reservoirs of the thermophilic campylobacters ( C jejuni , C coli , and C lari ). It is estimated that over half of all commercial broiler and turkey flocks harbor C jejuni . The organism has been isolated from numerous birds, including Columbae and domestic and free-living Galliformes and Anseriformes. Campylobacter jejuni has been demonstrated in poultry in all areas where commercial production occurs. Isolation of the organism is a function of surveillance and ability of laboratory personnel to culture and identify Campylobacter spp . Etiology and Epidemiology: Campylobacter jejuni is the predominant species associated with food-borne infection derived from poultry. Campylobacter coli and C lari are occasionally recovered from the intestinal tract of poultry, and both have been implicated in food-borne infection. Environmental contamination is regarded as the source of infection for poults, chicks, and ducklings. Litter can remain infective for long periods, subject to at least a 10% moisture level and neutral pH. Infected chicks and poults become colonized and can continue to excrete C jejuni for up to 2 mo. Contaminated water can introduce infection into poultry flocks, and nonchlorinated water derived from a dam, river, or shallow well should be regarded as a possible source. Flocks can be infected by rats, wild birds, and house flies; equipment and footwear contaminated with feces from an infected source may also serve as a vehicle of transmission of C jejuni . Once introduced into the environment, rapid transmission within the flock occurs, with subsequent colonization of a high proportion of exposed breeders, commercial-meat, or laying-strain poultry. Campylobacter jejuni is not transmitted vertically, either on the surface of eggs or by transovarial transmission. Clinical Findings and Lesions: Infecting day-old chicks with a pathogenic and invasive strain of C jejuni results in a rapid onset of diarrhea that may persist for up to 4 days. Highly pathogenic isolates derived from people with enterocolitis may induce up to 32% mortality in chicks. Chicks >7 days old are refractory to infection. Gross lesions of Campylobacter infection in neonates include distention of the jejunum, disseminated hemorrhagic enteritis, and in some cases, focal hepatic necrosis. Microscopic lesions include edema of the mucosa of the ileum and cecum with C jejuni in the brush border of enterocytes. Mononuclear infiltration of the submucosa and villous atrophy occur with intraluminal accumulation of mucus, erythrocytes, and both mononuclear and polymorphonuclear cells. Diagnosis: Fecal specimens should be collected using rayon-tipped swabs, then placed in semisolid Cary-Blair transport medium. Enrichment culture of specimens in semisolid motility medium facilitates isolation when small numbers of C jejuni are present in a sample. Campylobacter should be cultured on selective media containing brucella agar base and bovine blood with up to seven antibiotics that inhibit overgrowth of other Enterobacteriaceae. Thermophilic Campylobacter spp should be cultured at 42°C under microaerophilic conditions for 48 hr. Campylobacter spp of significance in poultry are oxidase- and catalase positive, indole negative, and reduce selenite. The three thermophilic species can be differentiated on the basis of nalidixic acid sensitivity and hippurate hydrolysis; the Penner or Lior serotyping schemes can be used to classify C jejuni . Bacterial restriction endonuclease DNA analysis can distinguish among various C jejuni isolates. Control and Prevention: Because C jejuni does not occur as a specific pathogen under commercial conditions, treatment of poultry flocks is not a consideration. If C jejuni is considered a problem in companion bird aviaries or in exotic species, antibiotics such as erythromycin can be administered in drinking water. Galliformes should receive a dose of 10-30 mg/kg for 4 consecutive days, and Psittaci and exotics should be medicated at 30-40 mg/kg. Preharvest prevention of Campylobacter infection in commercial species is based on strict biosecurity, decontamination of housing between successive flocks, exclusion of rodents and wild birds, and insect eradication. Chlorination of drinking water to 2 ppm and operating farms on a strict all-in/all-out basis can reduce the prevalence of infection. In the context of commercial production in the USA where earth-floored housing is used and litter is recycled, preharvest control of C jejuni is impractical. Innovative methods of prevention, such as competitive inhibition or the use of vaccines, are under intensive investigation, but these methods are unlikely to be available for commercial application in the near future. Withholding feed from broilers and turkeys for at least 12 hr before slaughter and thorough decontamination of transport coops and modules reduce fecal contamination and lower the level of C jejuni introduced into processing plants. Zoonotic Risk: Campylobacter jejuni is a major source of food-borne enteritis in consumers; contaminated, undercooked poultry is responsible for >50% of cases investigated. The condition was recognized in the mid-1970s, and the significance of the organism has become apparent with improved methods of isolation and identification. In addition to contaminated poultry, nonchlorinated ground water, young diarrheic pets, and contaminated beef and pork products may also be responsible for infection of people. Campylobacter jejuni contamination can be reduced by improved washing of carcasses, the use of counter-flow scalding, elimination of immersion chillers, and reduction in manual handling by installation of advanced automated equipment. Chemical disinfectants, such as glutaraldehyde (0.125%) and succinic acid (3%), and organic compounds, such as lactic and acetic acids, may be used to destroy C jejuni when used as a spray or an immersion treatment. Gamma irradiation at levels ranging from 1 to 3 kGy effectively eliminates C jejuni from poultry carcasses and products. Recent studies have demonstrated that irradiation using cobalt 60 and electron beam generation are cost-effective procedures, and they are endorsed by a joint United Nations Committee of the Food and Agricultural Organization, the International Atomic Energy Agency, and the World Health Organization. The only current measure to reduce the risk of C jejuni infection to consumers is thorough cooking of poultry to achieve a core temperature of 74°C for 1 min. This ensures destruction of C jejuni . Concurrent hygienic storage, handling, and preparation is necessary to prevent contamination of prepared foods, work surfaces, and utensils by raw poultry and other meats. |
