What do we know about Q fever in Mexico?

In Mexico, Q fever is considered a rare disease among humans and animals. From March to May of 2008, three patients were referred, from the state of Hidalgo to a tertiary-care center in Mexico City, with an acute febrile illness that was diagnosed as Q fever. We decided to undertake a cross sectional pilot study to identify cases of acute disease in this particular region and to determine the seroprevalence of Coxiella burnetii among healthy individuals with known risk factors for infection with this bacteria. Q fever was defined according to the Centers for Disease Control and Prevention criteria. All subjects were interviewed for signs and symptoms of the disease, demographic and household characteristics and occupational exposure to cattle. Blood samples were taken from hospitalized and outpatients with symptoms suggestive of Q fever, as well as from asymptomatic individuals with direct and daily exposure to cattle (slaughterers, butchers, farmers, shepherds and veterinarians) in the five municipalities. We report the occurrence of 17 cases with positive antibodies against C. burnetii in a rural area of central Mexico; eight cases had clinical criteria of acute Q fever disease. Results from this pilot study underscore the need for active surveillance programs and comprehensive studies to further define the prevalence and risk factors associated with the disease in Mexico, to know more about its clinical presentation and to characterize bacterial factors involved in its pathogenesis.