Serological and Molecular Evaluation of Leishmania infantum Infection in Stray Cats in a Nonendemic Area in Northern Italy

Abstract

Infection by Leishmania species is increasing worldwide. It was hypothesized recently that cats act as a secondary reservoir for Leishmania infection. The aim of the present study was to assess the prevalence of Leishmania infantum antibodies and DNA in blood samples collected in a sample of stray cats in metropolitan area of Milan in northern Italy, which is a nonendemic area for leishmaniasis. An indirect immunofluorescence antibody test for L. infantum showed that 59 of 233 cats (25.3%) were seroreactive, 38 samples (16.3%) had antibody titers of 1 : 40, 15 (6.4%) had antibody titers of 1 : 80, and 6 (2.6%) had antibody titers of 1 : 160. Feline immunodeficiency virus (FIV) seropositive status was statistically associated with seroreactivity to L. infantum (P = 0.01) as shown by univariate and multivariate logistic regression (P = 0.0098; OR = 7.34). All blood samples that were tested using real-time PCR were negative for parasite DNA. These results were surprising, since no autochthonous human or canine cases of leishmaniasis have ever been reported in this region of northern Italy. It is possible that this high seroreactivity to L. infantum could be due to cross-reaction with antigens from other parasites. Additional studies that include parasite isolation are needed to clarify our findings on feline leishmaniasis in this region.

Prevalence of Leishmania infantum and co-infections in stray cats in northern Italy

“…This is the second study to examine stray cats from the city of Milan for L. infantum infection. A previous study [22] reported a seropositivity of 6.4% for L. infantum at titers ≥1:80 (15 seropositive out of 233 cats tested) in stray colony cats, in contrast to the total negativity of blood samples analyzed by rPCR. Seropositivity for L. infantum was re-evaluated 4 years later in the present study in a similar population of stray cats in order to take advantage of the increased diagnostic sensitivity of newer PCR techniques for the identification of L. infantum in whole blood, lymph node aspirates, and oculoconjunctival samples.…”

Detection of Leishmania spp. using parasitological, serological and molecular assays in asymptomatic and sick cats from an endemic area of visceral leishmaniosis in Brazil

“…However, little is known about the clinical manifestations and immune response to the disease in these animals, which is well-established in dogs. Thus, various techniques have been used in the diagnosis of FL, such as serological, parasitological and molecular techniques [5,7,11,12,14,18,32,41].…”

“…Feline leishmaniosis (FL) cases have been reported in South America [5,[7][8][9][10][11], and in Europe [12][13][14][15][16][17][18] and Asia [19][20][21]. More properly in many cats the Leishmania infection is associated with an immunosuppressive condition due to feline leukemia virus and feline immunodeficiency virus, and for this reason there can be an overlap of clinical symptoms or the immunosuppression can promote the development of visceral forms of leishmaniosis [22].…”

Feline leishmaniosis: Is the cat a small dog?

“…Dirofilaria immitis, Ehrlichia canis, Hepatozoon canis) can influence parasite burden and progression of CanL (De Tommasi et al, 2013;Morgado et al, 2016;Tabar et al, 2013). In cats the association between retroviral, coronavirus, Toxoplasma or some vector-borne co-infections in cats antibody and/or PCR positive to L. infantum has been explored (Attipa et al, 2017;Ayllón et al, 2012;Pennisi et al, 2012Pennisi et al, , 2000Pennisi et al, , 1998Persichetti et al, 2016;Sherry et al, 2011;Sobrinho et al, 2012;Solano-Gallego et al, 2007;Spada et al, 2016Spada et al, , 2013Vita et al, 2005). A significant association between Feline Immunodeficiency Virus (FIV) and L. infantum positivity was found only in few cases (Pennisi et al, 1998;Sobrinho et al, 2012;Spada et al, 2013).…”