Chapter 4
Transmission of Campylobacter jejuni
Transmission of and Infection with Campylobacter jejuni Bacteria
Most Campylobacter infections in humans are caused by the consumption of contaminated food or water. [5] Direct contact with infected animals, including pets, is also a well-documented means of disease-transmission. [1, 6]
Although not common, person-to-person transmission can also occur. [5, 6] Males and females appear to be equally affected, although the prevalence of infection in otherwise healthy people is quite low. [5] Population-based studies show that the peak incidence of infection is in children one year of age and under, and in persons between 15 and 29 years of age. [26] Incidence of Campylobacter infection in HIV-positive individuals is higher than in the general population. [1, 5]
The infective dose—that is, the amount of bacteria that must be ingested to cause illness—is relatively small. [5, 28] Ingestion of as few as 500 organisms, an amount that can be found in one drop of chicken juice, has been shown to cause human infection. [5, 12, 28] Despite this low infectious dose, and the ubiquity of Campylobacter in the environment, most cases of Campylobacter infection occur as isolated, sporadic events, and are not usually part of large outbreaks. [1, 26] But, very large outbreaks (greater than 1,000 illnesses) have been documented, most often from consumption of contaminated milk or unchlorinated water supplies. [1, 5, 6, 28]
