Veterinary Research Forum

Abstract Leptospirosis is a worldwide zoonotic disease caused by pathogenic Leptospira spp., often occurring in tropical and subtropical regions. Focusing on development of rapid diagnostic methods to facilitate early diagnosis and a universal vaccine are the main critical issues to overcome the burden of leptospirosis. Here, we have studied the immunogenic potential of prepared recombinant Loa22 protein (rLoa22) of local pathogenic Leptospira species in mice and its ability to induce humoral and cellular immunity, being further evaluated by analyzing the immunoglobulin G (IgG) subclasses and cytokines produced through immunization. Based on the results, mice immunized with rLoa22/adjuvant and a trivalent vaccine, induced high titers of total IgG. All immunized groups increased IgG1 almost on the same level; but, IgG2a level was significantly higher in the vaccine and rLoa22/adjuvant groups than rLoa22 alone group. Animals immunized with the vaccine produced more interleukin 4 than rLoa22/ adjuvant group. The results of evaluating interferon gamma level showed that the rLoa22/adjuvant and vaccine groups had a significant increase compared to the rLoa22 alone group. The results also demonstrated that the rLoa22 protein, in indirect enzyme-linked immunosorbent assay, was able to detect the anti-Leptospira antibodies in mice serum that can be used as a marker in assessing the seroprevalence of leptospirosis and/or in combination with other leptospiral antigens in development of an effective vaccine against leptospirosis.

Abstract Leptospirosis, a zoonotic disease, is characterized by fever, jaundice, abortion and hemo-globinuria. It is widespread and the determination of the dominant serotype in the animal species of each region accelerates the control and prevention program. 862 blood samples were prepared from ruminants and equines. Serum antibody of leptospira serovars were determined based on gender and age parameters. Sera were examined by microscopic agglutination test (MAT) with six live serotypes. The overall prevalence was 22.30%, with the highest (37.00%) and the lowest (6.60%) in Holsteins and mules, respectively. The overall male and female incidence were 12.20% and 9.86%, respectively, which was not different. The highest gender infection was in male Holsteins (19.20%) and the lowest were in male Simmentals and mules (1.72%). The highest dilution was 1:100 for pomona and the lowest was for canicola. All animals responded positively to grippotyphosa. The highest infection to one serovar was in Holsteins and the lowest for four serovars were in goats and Simmentals. Males less than 1.5 years old showed the highest infection. Age differences in leptospira infection except for sheep was significant. In conclusion, leptospira infection in ruminants was high compared to equines. Gender differences were not significant. The highest dilution was 1:100, with pomona in ruminants and grippotyphosa in all species. Leptospiral infection was increased with age and the differences among animals except for sheep were significant. Finally, regarding 22.30% infection rate, vaccination is necessary to Holsteins, and preventive measures for others. Health advices would be necessary for human safety.

Abstract Immune-mediated hemolytic anemia (IMHA) is a common cause of anemia in dogs. The immune aggression towards erythrocytes can be triggered by many pathological conditions such as infection, inflammatory disease or neoplasia. Upon ruling out any eliciting conditions, a diagnosis of the primary immune-mediated disease can be made. In this particular case of severe anemia (tested positive for circulating antibodies against red blood cells with flow cytometry), vector-borne diseases (which are a common cause of immunopathology in Mediterranean countries) were excluded, leptospirosis was not. This resulted in an unsuccessful immunosuppressive therapy with prednisone, two whole blood transfusions and ultimately death of the patient. Leptospirosis (confirmed positive in two tests, micro-agglutination test for antibodies and PCR for microbial DNA in urine), can mimic a primary IMHA and must be considered in its differential list of causes. A liver involvement, that included elevated serum activity of liver enzymes and increased serum bile acid was observed at the admission and suggested an etiopathogenesis other than a primary IMHA.