Zoonotic pathogens are frequently hypothesized as emerging with the origins of farming, but evidence from the archaeological records is lacking. Professor Dirk Pfeiffer and an international research team carried out a study on brucellosis transmission in goat populations in the Neolithic period, which attempted to provide evidence to support the unconfirmed hypothesis on the causal link between early animal farming and zoonotic disease.
Brucella melitensis is the main agent responsible for human brucellosis and today’s most common bacterial zoonosis in the world1. A model simulating the transmission of Brucella melitensis within early domestic goat populations was developed. It was informed by archaeological data describing goat populations in Neolithic settlements in the Fertile Crescent.
The research outcomes generated by mathematical modelling have shown that the pathogen could have been sustained even at low levels of transmission within domestic goat populations, as a result of the characteristics of early animal farming which promoted disease invasion and maintenance. They include the creation of dense populations, alternation of demographic profiles such as selective harvesting of young male goats possibly for the purpose of increasing productivity, and probable interactions between Neolithic settlements. With fostering conditions for domestic goats to act as reservoirs of Brucella melitensis, the early stages of agricultural development were likely to promote the exposure of humans to this pathogen.
Through examining the changing dynamics of human–animal relationships at the start of farming, the study advances understanding of the consequences of farming on human and animal health and wellbeing. It also provides long-term perspectives for present and future animal management to ensure sufficient and reliable food supply for the ever-growing global human population. Besides, it further demonstrates the importance of recognizing the complexity of eco-social systems, where it is often very difficult to obtain a holistic view of different types of impacts that a particular change in the system creates. The paper titled “Early animal farming and zoonotic disease dynamics: modelling brucellosis transmission in Neolithic goat populations” was published in the Royal Society Open Science journal in February 2017 and can be downloaded at http://dx.doi.org/10.1098/rsos.160943.
1 Pappas G, Papadimitriou P, Akritidis N, Christou L, Tsianos EV. 2006 The new global map of human brucellosis. Lancet Infect. Dis. 6, 91–99. (doi:10.1016/ S1473-3099(06)70382-6)