Fig. 3

Risk evaluation of tick-borne brucellosis transmission. (1) After adult ticks become infected with Brucella, there is the potential for vertical transmission to occur, leading to the infection of different developmental stages of ticks through eggs. (2) Infected ticks have the capability to transmit Brucella to humans. (3) Ticks may also transmit Brucella after biting healthy animals. (4) There is a possibility of “co-feeding transmission” where infected, healthy ticks feed on the same host. This complex mode of transmission highlights the intricate interactions between ticks, hosts, and pathogens in natural ecosystems. Note: the solid lines on the diagram denote confirmed transmission routes, while the dotted lines indicate potential transmission routes