Time course of Leishmania infantum infection in naturally infected dogs in endemic area

Introduction and aim of the study - The clinical evolution of Leishmania infantum infection in dogs is largely influenced by the host's individual immune response. Few studies have investigated the time-course and clinical evolution of the infection both under experimental and natural conditions. In the present investigation, the time-course of L infantum infection was studied by monitoring clinical and laboratory features in naturally infected animals. Material and methods - The study starts from 218 dogs resulted negative to diagnostic tests for L infantum on March 2005, of which 23 dogs positivized to one or more diagnostic tests between November 2005 and March 2006.The infected animals were monitored serologically (IFAT), parasitologically (lymph-node smear microscopical examination, PCR on dermal tissue) and clinically, through a clinical-pathological score, every 4 months till March 2007. Results - After assessing the diagnostic tests over time and the clinical scores, the time course of infection was defined as transient asymptomatic infection (II dogs), persistent asymptomatic infection (2 dogs), patent symptomatic infection (8 dogs). Discussion -The results of this study confirm the high variability of the L infantum infection progression in endemic areas and underline the difficulty to propose a clear method to define the clinical status of the infection with single-time samples. So it's advisable to monitor infected animals over time in order to make easier any clinical interpretation or the beginning of a possible therapy.