Brucellosis outbreak in a rural endemic region of Mexico - A comprehensive investigation

Brucellosis is a worldwide zoonotic disease. Generally, humans can be infected by either the consumption of raw milk and fresh cheeses made from unpasteurised milk or by contact with infected animals, mainly in endemic regions. In this study, we investigated a brucellosis outbreak in State of Guanajuato, an endemic region of Mexico. Microbiological culture of human blood, raw milk from cows and goats, and fresh cheeses was performed to isolate Brucella. Identification of the bacteria was done by bacteriological procedures and by multiplex Bruce-ladder polymerase chain reaction (PCR). Brucella melitensis was isolated from patients, infected goats, and fresh goat cheeses; while Brucella abortus was isolated from cows. All patients had eaten fresh cheese, but no occupational exposure to animals was reported. The results of molecular typing did not show any Brucella vaccine strains. The isolation, identification, and molecular characterisation of Brucella spp. in both human brucellosis cases and infected animals are very important to identify the source of infection and to take control measures in endemic regions.