Human–livestock contacts and their relationship to transmission of zoonotic pathogens, a systematic review of literature

Klous, Gijs; Huss, Anke; Heederik, Dick J.J.; Coutinho, Roel A.

Other research in farmers mainly focussed on antimicrobialresistant zoonotic organism carriage. These studies often have a different design, utilising cross-sectional or cohort designs, occasionally with repeated measurements. LA-MRSA [64] can be transmitted between animal species [65] and from animals to humans [65] [66] [67] [68] , but also from animals to the farm environment, although the host preferences differ [65, 69] . One study identified a correlation between the carriage prevalence in pigs and the likelihood of human LA-MRSA carriage [70] . Still, the prevalence of persistent LA-MRSA carriage among farmers is relatively low [71] and most individuals show relatively rapid clearing of LA-MRSA carriage [19, 66] . In poultry farms, MRSA positivity was found to be less prevalent compared to veal calf and pig farms. This could explain the limited carriage in poultry workers [72] and among people who keep poultry at home [73] . In addition, the reverse transmission route has also been proposed, with the evidence for a reverse zoonosis/anthroponosis being pigs positive for healthcare associated-MRSA, thus indicating farmer-to-pig MRSA spread [74] . This theory is enhanced by evidence showing that LA-MRSA is less transmissible between people, compared to other MRSA types [75] . Table 2 Overview of micro-organisms reported in selected publications. The columns depict; the micro-organisms reported in studies, animals involved carrying or infected with the micro-organism, transmission of a disease; excretion site of the microorganism to uptake site, transmission pathway; mode of transmission of the micro-organism, number of identified studies, reference number. Transmission pathways as defined in indicated references.