ABSTRACT
We conducted a genome-wide scan for visceral leishmaniasis in mixed-breed dogs from a highly endemic area in Brazil using 149,648 single nucleotide polymorphism (SNP) markers genotyped in 20 cases and 28 controls. Using a mixed model approach, we found two candidate loci on canine autosomes 1 and 2. The positional association on chromosome 2 mapped to a predicted DNAse sensitive site in CD14+ monocytes that serve as a cis-regulatory element for the expression of interleukin alpha receptors 2 (IL2RA) and 15 (IL15RA). Both interleukins were previously found to lead to protective T helper 1 cell (Th1) response against Leishmania spp. in humans and mice. The associated marker on chromosome 1 was located between two predicted transcription factor binding sites regulating the expression of the transducin-like enhancer of split 1 gene (TLE1), an important player in Notch signaling. This pathway is critical for macrophage activity and CD4+ T cell differentiation into Th1 and T helper 2. Together, these findings suggest that the human and mouse model for protective response against Leishmania spp., which involves Th1 and macrophage modulation by interleukins 2, 15, gamma interferon and Notch signaling, may also hold for the canine model.
Subject(s)
Genome-Wide Association Study , Interleukin-2 Receptor alpha Subunit/genetics , Leishmaniasis, Visceral/genetics , Receptors, Interleukin-15/genetics , Animals , Brazil , CD4-Positive T-Lymphocytes/metabolism , Cell Differentiation/genetics , Co-Repressor Proteins , Dogs , Genotype , Humans , Leishmania infantum/pathogenicity , Leishmaniasis, Visceral/pathology , Leishmaniasis, Visceral/veterinary , Polymorphism, Single Nucleotide , Receptors, Notch/genetics , Repressor Proteins/genetics , Signal Transduction , T-Lymphocytes, Helper-Inducer/metabolism , T-Lymphocytes, Helper-Inducer/pathologyABSTRACT
O cão doméstico desempenha importante papel como reservatório na transmissão da leishmaniose visceral ao homem, zoonose de grande importância em saúde pública. Realizou-se avaliação epidemiológica da leishmaniose visceral em 1.112 cães domiciliados no município de Poxoréo, estado do Mato Grosso e observou-se prevalência de 7,8 por cento. Observou-se ainda associação estatisticamente significativa entre a prevalência de leishmaniose visceral canina e as variáveis faixa etária, presença de sinais clínicos e presença de outra espécie animal co-habitando com os cães avaliados, tendo sido as galinhas mais freqüentemente observadas entre os animais soropositivos. O sexo, a coleta de lixo domiciliar bem como a renda familiar não apresentaram associação estatisticamente significativa com a prevalência da leishmaniose visceral canina. A análise dos resultados sugere que cães com idade superior a sete anos e a , presença de outra espécie animal co-habitando com os cães podem ser fatores de risco para a leishmaniose visceral canina.
Dogs play an important role as reservoir in the domestic cycle of visceral leishmaniasis, a serious public health problem. An epidemiological survey in 1,112 dogs was conducted at the Municipality of Poxoréo State of Mato Grosso, Brazil, using indirect immunofluorescence antibody test where the prevalence was 7.8 percent. Significant association was found between prevalence of canine visceral leishmaniasis and age of the dogs. Clinical signs and presence of other animals in the backyard, like chicken being more likely associated with seropositivity. Gender, garbage collection in the residence and family financial income were not associated with visceral leishmaniasis prevalence. Analysis of the results suggests that dogs aging more than 7 years and presence of another animal species co-inhabiting with the dogs may be risk factors for canine visceral leishmaniasis.
Subject(s)
Animals , Dogs , Female , Male , Dog Diseases/epidemiology , Dog Diseases/parasitology , Leishmaniasis, Visceral/veterinary , Brazil , Leishmaniasis, Visceral/epidemiologyABSTRACT
Dogs play an important role as reservoir in the domestic cycle of visceral leishmaniasis, a serious public health problem. An epidemiological survey in 1,112 dogs was conducted at the Municipality of Poxoréo State of Mato Grosso, Brazil, using indirect immunofluorescence antibody test where the prevalence was 7.8%. Significant association was found between prevalence of canine visceral leishmaniasis and age of the dogs. Clinical signs and presence of other animals in the backyard, like chicken being more likely associated with seropositivity. Gender, garbage collection in the residence and family financial income were not associated with visceral leishmaniasis prevalence. Analysis of the results suggests that dogs aging more than 7 years and presence of another animal species co-inhabiting with the dogs may be risk factors for canine visceral leishmaniasis.
Subject(s)
Dog Diseases/epidemiology , Dog Diseases/parasitology , Leishmaniasis, Visceral/veterinary , Animals , Brazil , Dogs , Female , Leishmaniasis, Visceral/epidemiology , MaleABSTRACT
Canine and human visceral leishmaniasis is endemic in several States of Brazil, and it is associated with infected dogs and the presence of the vector. Aiming at using polymerase chain reaction as a diagnostic tool in dogs, we amplified a 120bp fragment from kDNA of Leishmania spp. by PCR in blood samples. The lower detection limit observed was 0.1 parasites per 500microL of blood, which is a highly satisfactory result. On the other hand, PCR evaluation in 166 blood samples of dogs from Poxoréo, MS, Brazil, resulted in 55% sensitivity and 66.3% specificity, considering indirect imunnofluorescent test as gold standard.