Detecting antibodies to Leishmania infantum in horses from areas with different epizooticity levels of canine leishmaniosis and a retrospective revision of Italian data.

BACKGROUND: Leishmania infantum is a vector-borne pathogen endemic in countries in the Mediterranean basin, including Italy. Dogs act as the primary reservoir for this parasite, but other animal species may also be infected. Low-to-moderate seroprevalence levels of infection have been reported in apparent healthy equine populations in southern Europe, reinforcing the importance of exploring those species, including horses, that act as a food source for vectors and may thus participate in the epizoological scenario of canine leishmaniosis (CanL) and zoonotic visceral leishmaniosis (ZVL). Since little is known regarding the exposure to L. infantum in horses in Italy, we assessed the seroprevalence in healthy equine populations from different CanL endemic areas. METHODS: The survey was conducted on 660 apparently healthy horses distributed throughout central and northern regions of Italy between 2016 and 2019. Blood samples were collected and the presence of anti-Leishmania antibodies (IgG) was investigated by the immunofluorescence antibody test. Information on the location and altitude of the stables, along with the horses' breed, age, sex, and reproductive status was obtained by filling in a questionnaire. This was then used for statistical analysis by generalized linear models to explore risk factors associated with seroreactivity to L. infantum. RESULTS: An average seroprevalence of 13.9% was detected for L. infantum in the equine populations investigated, with statistically significant associations between seroprevalence, geographical variables (northern vs central Italy, origin and altitude) and individual factors (i.e. age and breed morphotype). CONCLUSIONS: Our results highlight that horses are frequently exposed to L. infantum. Further prevalence surveys in horses, also using direct methods (e.g. PCR), are warranted to clarify the role of these hosts in the epidemiology of Leishmania in Italy.

Prevalence and characterisation of shigatoxigenic Escherichia coli isolated from beef cattle fed with prebiotics.

Ten Holstein Friesian calves were divided into two groups of five: one group was given prebiotics in their food, while the other group served as the control group. Every two weeks from birth up to 18 months, samples of feces were taken from the rectal ampulla to determine the concentration of E. coli. At each sampling session, three aliquots per sample were collected. The arithmetic mean was calculated and all values (converted into logs) were analysed with GraphPad InStat for analysis of variance, followed by the Tukey-Kramer test. A total of 69 E. coli strains were detected, 29 (42.03%) from treated animals and 40 (57.97%) from the control group. The isolates were analysed by PCR for the presence of the stx-1, stx-2, hly and eae genes and by the Kirby Bauer test for susceptibility to the most commonly used antimicrobials in cattle breeding. Hierarchical clustering of the isolates was done using Ward's method. Thirty samples were positive for the stx-1 gene, 18 for stx- 2, 12 for both stx-1 and stx-2, 8 for hly, and 10 for eae. 4.3% were resistant to sulfamides, 8.6% to tetracycline, 1.4% to gentamicin, 94.6% to cephalothin, 2.8% to chloramphenicol, 13% to ampicillin, 13% to amoxicillin/clavulanic acid, 7.2% to sulphonamides, 4.3% to ceftriaxone, 5.7% to nalidixic acid, 34.7% to ticarcillin, 88.5% to erythromycin, and 5.7% to streptomycin. The isolates from the samples taken from day 210 to day 300 were grouped into a single cluster. Bacteriological examinations showed a reduction in the concentration of E. coli in the feces of the treated animals compared to the control group. The presence of strains with shigatoxigenic Escherichia coli virulence profiles and the reduction of these in the treated animal group demonstrated that diet can play an important role in reducing E. coli prevalence in cattle.