How does Brucella abortus infect human beings?
D000368:Aged; D000818:Animals; D002003:Brucella abortus; D002006:Brucellosis / Q000635:transmission*; D002417:Cattle; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008892:Milk / Q000382:microbiology; D009790:Occupations; D012737:Sex Factors