Genetic diversity and phylogenetic relationships between Leishmania infantum from dogs, humans and wildlife in south‐east Spain

Abstract

Leishmania infantum causes human and canine leishmaniosis. The parasite, transmitted by phlebotomine sand flies, infects species other than dogs and people, including wildlife, although their role as reservoirs of infection remains unknown for most species. Molecular typing of parasites to investigate genetic variability and evolutionary proximity can help understand transmission cycles and designing control strategies. We investigated Leishmania DNA variability in kinetoplast (kDNA) and internal transcribed spacer 2 (ITS2) sequences in asymptomatically infected wildlife (n = 58) and symptomatically and asymptomatically infected humans (n = 38) and dogs (n = 15) from south‐east Spain, using single nucleotide polymorphisms (SNPs) and in silico restriction fragment length polymorphism (RFLP) analyses. All ITS2 sequences (n = 76) displayed a 99%–100% nucleotide identity with a L. infantum reference sequence, except one with a 98% identity to a reference Leishmania panamensis sequence, from an Ecuadorian patient. No heterogeneity was recorded in the 73 L. infantum ITS2 sequences except for one SNP in a human parasite sequence. In contrast, kDNA analysis of 44 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. Genotype frequency was significantly greater in symptomatic compared to asymptomatic individuals. Both methods similarly grouped parasites as predominantly or exclusively found in humans, in dogs, in wildlife or in all three of them. Accordingly, the phylogenetic analysis of kDNA sequences revealed three main clusters, two as a paraphyletic human parasites clade and a third including dogs, people and wildlife parasites. Results suggest that Leishmania infantum genetics is complex even in small geographical areas and that, probably, several independent transmission cycles take place simultaneously including some connecting animals and humans. Investigating these transmission networks may be useful in understanding the transmission dynamics, infection risk and therefore in planning L. infantum control strategies.

Molecular xenomonitoring and host identification of Leishmania sand fly vectors in a Mediterranean periurban wildlife park

“…Vectors, susceptible hosts and L. infantum (pathogen) need to converge in time and space for efficient pathogen transmission (Kent, ). PCR detection of L. infantum in three wolves and one brown bear indicates that infection is present in the park, and canids are competent L. infantum reservoirs (Ortuño et al, ; Risueño et al, ). In addition, our results support the role of canines as common hosts of sand flies in the area.…”

“…Recently, L. infantum DNA was diagnosed by PCR in skin samples from three wolves ( Canis lupus ) and one brown bear ( Ursus arctos ) from the Murcia city wildlife park, in south‐east Spain (Ortuño et al, ; Risueño et al, ). The area is L. infantum endemic, and the estimated PCR prevalence was 67% in dogs (Chitimia et al, ), 32% in free wildlife (mostly foxes, rabbits and rodents) (Risueño et al, ) and 8% in human blood donors (Pérez‐Cutillas et al, ).…”

Serological study of feline leishmaniasis and molecular detection of Leishmania infantum and Leishmania braziliensis in cats (Felis catus)

“…These results show the genetic complexity of Leishmania spp. populations which circulate in a different geographical area but in the same species (Cupolillo et al, 1998;Ortuño et al, 2019). On the other hand, isolated samples from Brazilian domestic cats were phylogenetically close to isolated samples from domestic dogs, which indicates that possibly L. infantum circulating in Brazil is present in both species.…”

Clinical leishmaniosis in a captive Eurasian otter (Lutra lutra) in Spain: a case report

“…Natural infection by L. infantum in wildlife species in South-Eastern Spain was described in captive wolves and brown bears, and in free-ranging wildlife species such as foxes, rabbits and rodents [ 17 , 18 ]. In addition, Muñoz et al [ 2 ] reported sand fly vector abundance in the ‘Terra Natura’ wildlife park.…”