New Insights on Leptospira Infections in a Canine Population from North Sardinia, Italy: A Sero-Epidemiological Study

Abstract

Leptospirosis is a widespread zoonosis recognized as a re-emerging infectious disease in a wide variety of animal species, including humans and dogs. No data exist regarding the presence of Leptospira species in the canine population of Sardinia Island. This study reports the first sero-survey for leptospirosis in kennel and owned dogs from six areas of the north of Sardinia. Sera from 1296 dogs were tested by microscopic agglutination test (MAT) specific for nine different serovars that are known to be well widespread in the Mediterranean environment. Moreover, kidney homogenates from rodents collected from the study area were also analyzed by LipL32 real-time PCR and multi-locus sequence type (MLST) on the basis of the analysis of seven concatenated loci. A total of 13% of the examined sera (95%CI: 11–15) tested positive for one or more serovars of Leptospira MAT detected; antibodies for serogroup Icterohaemorrhagiae (57%; 95%CI: 49–65) were the most common, followed by serovars Bratislava (22%; 95%CI: 16–28), Canicola (14%; 95%CI: 9–19), and Grippotyphosa (7%; 95%CI: 3–11). MLST analyses on isolates from rodents identified L. interrogans and L. borgpetersenii genomospecies. Different serovars belonging to pathogenic Leptospira serogroups are circulating in dogs from the island. Moreover, data obtained from rodents, indicated that rodents likely act as reservoir of spirochetes. Further sero-epidemiological studies are needed in order to obtain data from other collection sites in Sardinia and to increase the information on Leptospira species circulating in this area.

First Isolation and Molecular Typing of Pathogenic and Intermediate Leptospira Species from Urine of Symptomatic Dogs

“…Serological detection of pathogenic Leptospira strains from asymptomatic dogs was recently reported in Sardinia [18]. In the same study, Leptospira seropositivity was not correlated with shedding of the bacteria in dog urine and both rt-PCR and urine culture gave negative results.…”

“…All serum samples were subjected to the microscopic agglutination test (MAT), test as previously described [18]. MAT was performed using a panel of 9 serovars comprising of leptospires from the Mediterranean area.…”

“…5-Fluorouracil (5-FU) was added due to minimize bacterial contamination. Samples of kidney were homogenized as previously described [18]. A total of 1000 µL of urine and 25 mg of tissue were suspended in EMJH-fluorouracil semisolid medium at 28 • C and cultured for a period of three months.…”

“…In Sardinia, current literature still lacks information on the presence and typing of Leptospira species in dogs. Only one study reports the presence of different serovars belonging to pathogenic Leptospira serogroups isolated from asymptomatic dogs living in the island [18].…”

Are Small Animal Practitioners Occupationally Exposed to Leptospirosis? Results of a Serological Survey

“…Until now, vaccination against Leptospira is recommended in order to prevent the severe clinical diseases in dogs, more commonly caused by serovar Icterohaemorrhagiae in the northeast of Italy [12]. Furthermore, the most recent studies reported that vaccination of dogs with the new anti-Leptospira vaccine induces protective immunity against systemic disease, renal infection, and clinical signs [20], even if the available commercial vaccine formulations are not able to protect the dogs from Leptospira infection caused by emergent serogroups (Pomona, Sejroe) [21][22][23][24]. The widespread emergence of Leptospira strains requires the employment of specific diagnostic methods (MAT, molecular analysis, and genotyping) in order to better understand geographical distribution and to develop appropriate vaccine formulations.…”