Canine Leishmaniasis. Part I: Project Leishmania: Determining the seroprevalence of Leishmania infected dogs imported from the Mediterranean area. Part II: A focus on the polarisation into M1/M2 of canine macrophages in vitro in relation to canine Leishmaniasis

Abstract

In the Mediterranean area, a large reservoir of Leishmania infantum infected dogs is present. These dogs are imported into the Netherlands in considerable numbers, which leads to an increasing number of dogs suffering from leishmaniasis that present themselves to the Dutch veterinary practices. However, the seroprevalence of Leishmania in this imported population of dogs is still unknown. Therefore, Project Leishmania was founded to determine this seroprevalence. Part I of this paper describes the methodology of the database that was used to record the seroprevalence and other clinical findings in Project Leishmania participating dogs. Suggestions are offered to improve the database to minimise information bias and make future statistical analysis easier. Preliminary results show a Leishmania seroprevalence of 15.5% in imported dogs, which emphasises the need for awareness in Dutch veterinary practices for leishmaniasis in dogs with an importation history. Part II of this paper describes the research performed on the immunological aspect of Leishmania infections. Namely, an interesting characteristic of canine leishmaniasis is the fact that disease progression is extremely variable. Dogs can be infected and remain asymptomatic for long periods of time or they can develop mild to severe clinical symptoms. Research on leishmania infections in mammals show that the type 1 immune response, characterised by T-helper 1 cells and M1 macrophages, has been associated with parasite killing and asymptomatic infections, whereas the type 2 immune response, characterised by T-helper 2 cells and M2 macrophages, has been associated with parasite survival and symptomatic disease. Knowledge on these M1 and M2 macrophages in dogs is scarce and the specific role these macrophages play in relation to Leishmania infections has not been researched in dogs yet. Therefore, the polarisation of canine monocyte-derived macrophages into M1/M2 is investigated by the expression of cell surfaces molecules and genes that are described as M1/M2 specific markers in human and mice literature, through flow cytometry and qPCR. Results show that M1/M2 monocyte-derived macrophages were cultured successfully based on the M1/M2 specific markers. Future experiments are however necessary to successfully infect these monocyte-derived macrophages with Leishmania and consequently analyse the effects this has on the polarisation of M1/M2 or analyse the effect of M1/M2 on Leishmania survival.