Serological, molecular and clinicopathological findings associated with Leishmania infantum infection in cats in Northern Italy

Abstract

Objectives The aims of this study were to investigate the prevalence of Leishmania species infection in cats in Northern Italy and to evaluate the associations between infection and signalment and clinicopathological data. Methods The study was carried out in a veterinary university hospital from June to November 2017. Blood, urine, conjunctival swabs and hair were collected from all randomly selected cats. Leishmania species infection was evaluated using the indirect fluorescent antibody test (IFAT), setting a cut-off value of 1:80, and using real-time PCR on blood, conjunctival and hair samples. A complete blood count, serum chemistry profile, serum electrophoresis and urinalysis were also carried out. The cats were grouped on the basis of the results of the diagnostic criteria adopted in positive, negative and unconfirmed Leishmania cases. Non-parametric variables and continuous data were compared among the study groups using the χ2 test and the Mann–Whitney U-test, respectively. Results One hundred and fifty-two cats were included. Nineteen of the 152 (12.5%) cats were positive (18/152 [11.8%] showed an IFAT titre of ⩾1:80 and 1/152 [0.7%] was real-time PCR-positive from a hair sample); 106/152 (69.7%) cats were negative; and 27/152 (17.8%) cats were unconfirmed for Leishmania species. Total proteins, beta2-globulin and gamma-globulin were significantly increased in the positive Leishmania group compared with the negative group. Conclusions and relevance The results of the present study demonstrated the spread of Leishmania infantum infection in cats in Northern Italy. Hyperproteinaemia and hypergammaglobulinaemia appeared to be significant clinicopathological abnormalities in this population of cats with L infantum infection.

Feline Leishmania spp. Infection in a Non-Endemic Area of Northern Italy

“…While median alpha 2-globulins remain in reference range in FeL infected cats, median gamma-globulins increased more in infected than in uninfected cats. Gammopathy are found in most cases described in the literature [1,4,5,18,30,[48][49][50][51][52] with some cats showing also a normal proteinemia as in the feline population analyzed in this study. It can be hypothesized that in cats, as in dogs, the humoral immune response could also be activated by the production of immunoglobulins after infection, resulting in high concentrations of gamma-globulins.…”

“…Three RT-PCR-positive cats in this study had an IFAT titer <1:40, and one a titer of 1:40. Therefore, as previously shown [18], it seems that there was no agreement between the results obtained by IFAT and PCR. This is a common finding in cats from L. infantum endemic areas, where discordant results between serological and molecular techniques have been reported previously [7,24,[31][32][33][34].…”

“…In comparison with other recent studies [17,18] performed in cats living in cities in Northern Italy (shown in Table 3), the rates of infection in cats surveyed varied widely. This may be due to the methodology used (IFAT versus PCR, type of samples analyzed with PCR), the geographic area of Northern Italy studied and the population under study (cat's life style, owned versus stray cats).…”

“…The first two studies [8,16] relate to the same population of stray cats and were performed in previous years by the authors of this study. The last two studies [17,18] relate to owned cat populations from cats surveyed in cities located in Northern Italy. Canine leishmaniosis has spread northwards in Italy in the last decades [19,20], but data on the epidemiology of CanL in the Lombardy region are scant and out of date, therefore difficult to compare with results of the current study.…”

“…This may be due to the methodology used (IFAT versus PCR, type of samples analyzed with PCR), the geographic area of Northern Italy studied and the population under study (cat's life style, owned versus stray cats). Both previous studies were performed on owned cats in Northern Italy and had a seroprevalence at IFAT with ≥1:80 cut off titer rates from 1.3% to 11.8% [17,18]. The last study [18] performed by Urbani et al showed a very high seroprevalence (11.8%), more than double that found in the current study (4.9%), and this could due to the fact the feline population surveyed comes from a city closer to the L. infantum endemic foci of central Italy and that the Emilia-Romagna region has been considered to be an endemic area for CanL [20].…”