Impact of Human Granulocytic Anaplasmosis in Spain from 1997 to 2022.

Human granulocytic anaplasmosis (HGA) is an emerging zoonosis in Europe, with limited data available from Spain. This study aimed to quantify HGA cases in the Spanish National Health System over the last 26 years, assess its evolution, and evaluate the impact in terms of hospital stay and cost. A retrospective observational case series was conducted using the Minimal Basic Data Set (MBDS, CMBD in Spanish). Hospitalized patients with ICD-9-CM and ICD-10 codes for anaplasmosis from 1997 to 2022 were included. Ten HGA cases were reported. The incidence remained stable at one case per year [IR = 0.021 cases/million person-years], except in 2018 [IR = 0.048]. Six patients (60%) were men, with a mean age of 49 years (±20.9). Hospital stays ranged from 3 to 13 days. The total cost was EUR 45,540.57, with an average cost of EUR 4554.06 (±1032.16) per case. All patients had favorable outcomes. HGA has a low incidence in Spain, with moderate associated costs. Despite its emergence, its economic and health impact remains manageable, underscoring the effectiveness of Spain's healthcare system. Continued surveillance and prevention are essential to address evolving vector-borne diseases.