Bartonella henselae in Italy: a rare seasonal infection

BACKGROUND: Symptomatic Bartonella henselae infection is considered rare in Europe. Cat fleas transmit the microorganism between cats, but their role in transmission of B. henselae to humans has not been defined. The aim of our study was to perform a retrospective study of detected cases at our Hospital. METHODS: We retrospectively analyzed data of all children showing lymphadenopathy and a 4-fold increase in specific IgM for B. henselae over the period from June 2010 to May 2015. We therefore examined clinical data, laboratory exams in order to achieve a description of the expression of Bartonella infection in our series: age, geographical area of origin, symptoms, laboratory exams, the seat of the swelling lymph nodes with ultrasound description, and data on biopsy of lymph node when performed. RESULTS: We could identify a total of 7 patients (4 females, range of age: mean age 8.75 +/- 2.87 SD): three cases in 2011 and 1 case per year in 2010, 2012, 2013 and 2014 with an average distance between one case and the sequent of 246.16 +/- 214.54 days. All patients came from small towns with no preference between the inland and coastal areas. The infection was characterized only by lymphadenopathy with nonspecific alterations at blood tests and with no history of cat scratch. CONCLUSIONS: By our experience, Bartonella infection presents as a seasonal disease with increased incidence in autumn, with peaks in October, and a decrease after spring. In conclusion, infection with B. henselae is an issue to keep in consideration in all cases of lymphadenopathy, especially in children coming from small towns even without a declared cat scratch.