Which species is the leading cause of human Brucellosis in California?

Brucella melitensis is recognized as the leading cause of human brucellosis in California primarily due to its association with sheep and goat herding. This species is highly virulent and is commonly transmitted to humans through the consumption of unpasteurized dairy products, which are often made from infected animals. The prevalence of Brucella melitensis in regions with significant livestock populations, particularly those engaged in the production of cheese and other dairy products, contributes to its role as a major culprit in human cases of brucellosis.

This disease transmission is exacerbated in communities with close contact between livestock and humans, which is a common occurrence in agricultural areas of California. The vigilance in controlling this pathogen is critical, as it can lead to chronic health issues in infected individuals if not treated appropriately, highlighting the public health importance of understanding its transmission dynamics.