Serological survey on Leptospira infection in slaughtered swine in North-Central Italy

Abstract

Swine can act as asymptomatic carriers of some Leptospira serovars. In this study, 1194 sera from 61 farms located in five different Regions of North-West Italy were collected from slaughtered healthy pigs. Presence of antibody against four Leptospira serovars was evaluated. Overall, 52.5% of analysed farms presented at least one positive animal and 34.4% presented at least one positive swine with titre ⩾1:400. A percentage of 16.6% sera was positive and 5.9% samples presented a positive titre ⩾1:400. Tuscany and Lombardy showed the highest percentage of positive farms (64.3% and 54.6%, respectively) and sera (28.5% and 13.3%, respectively), probably due to environmental conditions and potential risk factors, which promote maintenance and spreading of Leptospira in these areas. The main represented serogroups were Australis (21.3% positive farms, 8.2% positive sera) and Pomona (18.0% positive farms, 8.1% positive sera). In swine, these serogroups are the most detected worldwide; however, our results seem to highlight a reemerging of serogroup Pomona in pigs in investigated areas. A low percentage of sera (0.6%) scored positive to Canicola, leaving an open question on the role of pigs in the epidemiology of this serovar. Higher antibody titres were detected for serogroups Australis and Pomona. Swine leptospirosis is probably underestimated in Italy and could represent a potential risk for animal and human health.

Potential sources of infection with selected zoonotic agents in the veterinary work environment – pilot studies

“…In the current study, anti-Leptospira spp. antibodies were detected in 59.3% of the pigs tested, which is a high prevalence, 2-3 times higher compared to similar studies performed in Italy [32] and Germany [33], and close to that reported by Cruz-Romero et al from small households in Mexico [34].…”

Presence and Characterization of Zoonotic Bacterial Pathogens in Wild Boar Hunting Dogs (Canis lupus familiaris) in Tuscany (Italy)

“…Pomona is a serogroup strictly connected to pigs. Indeed, Leptospira, which belongs to this serogroup, has been widely detected in the Tuscany region in domestic and wild swine [19,60,61], particularly in wild boar sampled in the same area and the same period [23]. Pomona was recently isolated in Tuscany from a crested porcupine [21]; even if the role of this animal as maintenance or accidental host is not still clear, this suggests a link to animals other than wild boar.…”

Preliminary Evaluation of In Vitro Bacteriostatic and Bactericidal Effect of Salt on Leptospira spp.

“…However, the reported high salt resistance, probably connected to a good environmental resistance, could be strictly connected to its epidemiology. This serovar, reported almost only in swine [51][52][53], seems to have not completely disappeared, but it occurs sporadically with low prevalence; perhaps it could remain in the environment for a long time even in the absence of a reservoir [30].…”