Advances in the epidemiology of leishmaniosis in animals and humansgenetic diversity of "Leishmania infantum", exposure to "Phlebotomus perniciosus" vector and coinfections with other pathogens

Abstract

Vector-borne infections are increasingly important and affect humans and animals worldwide. This PhD dissertation investigates several epidemiological aspects of sandfly-borne leishmaniosis and phlebovirosis, and tick-borne babesiosis and hepatozoonosis infections in dogs, cats, wildlife and humans in southern Spain. Chapter 1 studies the prevalence, associations and clinical features of Leishmania infantum, Hepatozoon spp. and Babesia spp. infections in 212 cats and 82 dogs from southeast Spain. Leishmania infantum DNA was detected in 44% of dogs and 21% of cats, Hepatozoon felis in 25% of cats, Hepatozoon canis in 13% of dogs, and Babesia vogeli in one dog. Hepatozoon spp. were identical to those found in wildlife. Chapter 2 estimates the prevalence and associations between L. infantum, Hepatozoon spp. and Babesia spp. in 151 wild animals. Results showed the presence of H. canis in foxes (91%) and beech martens (13%), Hepatozoon martis in beech martens (81%), wildcats (20%) and badgers (13%), H. felis in wild cats (60%), Babesia vulpes in foxes (64%), Babesia sp. type A closely related to B. vulpes, was detected in 58% badgers and Babesia sp. in 20% wildcats. Moreover, L. infantum infection was found in 29% foxes, 13% beech martens, 8% badgers and 1 of 3 Egyptian mongooses. It is the first report worldwide of H. martis in badgers and wildcats and H. canis in beech martens, and the first report in Spain of Babesia sp. in wildcats. We also detected Sarcocystis sp. in one genet and Cytauxzoon sp. in a wild cat. Leishmania infantum infected wildlife were more likely to be also infected with the apicomplexans Hepatozoon and Babesia spp. Chapter 3 presents a study investigating for the first time the degree of exposure of human blood donors to the vector Phlebotomus perniciosus by measuring their serological response to sandfly salivary gland homogenate (SGH) and recombinant protein rSP03B, and the prevalence and associations between L. infantum and Toscana and Sicilian phleboviruses. Among the 692 blood donors analysed, Toscana virus, Sicilian virus and L. infantum seroprevalences were 26%, 0% and 1%, respectively, and L. infantum-PCR prevalence was 2%. The percentage of donors with antibodies to SGH and/or rSP03B was 98%, but the correlation in the antibody optical densities to these antigens was relatively low (� = 0.39). The antibody response against SGH was associated to L. infantum and Toscana virus infections, but this was not the case for rSP03B, questioning its value as a diagnostic marker in humans. Finally, Chapter 4 analyses the genetic diversity of L. infantum in 38 humans, 58 wild animals and 15 dogs by analysing variability in kinetoplast and ITS2 DNA sequences by single nucleotide polymorphism (SNP) and restriction fragment length polymorphism (RFLP) analyses. Analysis of ITS2 sequences indicated that all samples were L. infantum except one L. panamensis from an Ecuadorian patient. Variability in L. infantum ITS2 sequences was low. In contrast, kDNA analysis of L. infantum sequences revealed 11 SNP-genotypes (nucleotide variability up to 4.3%) and four RFLP-genotypes including B, F and newly described S and T genotypes. Both methods similarly grouped parasites as predominantly or exclusively found in humans, in dogs, in wildlife or in all three of them. Results suggest that L. infantum might present several independent transmission cycles taking place simultaneously. The work carried out for this doctoral thesis contributes to our understanding of exposure to sand flies and the prevalence, transmission and susceptibility of sandfly and tick-borne pathogens in humans, domestic and wild animals in southern Spain and other areas where these pathogens are present, and emphasizes the importance of a global and One Health approach to the investigating and controlling these vector-borne infections