Leptospira interrogans serovar icterohaemorrhagiae seropositivity and the reproductive performance of sows

LEPTOSPIROSE SUÍNA

RESUMO A leptospirose suína é uma importante causa de prejuízos em rebanhos de reprodução, e ocorre em de todas as partes do mundo. A leptospirose suína pode se apresentar basicamente nas formas aguda e crônica. Na forma aguda, pode ocorrer febre, mastite focal e leptospirúria em animais adultos. Na forma crônica é comum a infertilidade, com a ocorrência de abortamentos, natimortos e nascimento de leitões fracos. Os sorovares Canicola, Pomona e Icterohaemorrhagiae são os mais importantes na epidemiologia da doença. Apesar das várias técnicas disponíveis e as que estão sendo desenvolvidas para o diagnóstico da leptospirose, a soroaglutinação microscópica ainda é a mais praticada, principalmente em suínos, sendo um teste considerado sorogrupo específico e a sua interpretação é complexa. O controle da leptospirose suína é baseado na imunização de suscetíveis, nas ações sobre as fontes de infecção, visando a diminuição da quantidade de leptospiras lançadas no ambiente e na identificação e eliminação dos fatores que ampliam a sobrevivência do agente. As vacinas anti-leptospirose suína são constituídas de bactérias íntegras inativadas polivalentes. Os sorovares comumente presentes são: Canicola, Icterohaemorrhagiae, Copenhageni, Pomona, Grippotyphosa e Bratislava. As proteínas, especialmente as de membrana externa e de superfície das leptospiras patogênicas, são antígenos efetivos para a produção de vacinas anti-leptospirose e têm se tornado um dos maiores pontos de interesse para o desenvolvimento de vacinas anti-leptospirose.

Influence of leptospirosis on reproductive performance of sows in Brazil

The purpose of this study was to investigate the association between seropositivity for the most frequent Leptospira serovars and reproductive losses in sows in Brazil. Serum samples from 351 sows from 18 herds (in the state of Rio de Janeiro, Brazil) with low reproductive efficiency were tested (microscopic agglutination) for antibodies against serovars of Leptospira. Antibodies were detected in serum samples of 66.1% of all sows, most frequently serovar icterohaemorrhagiae (43.1%), followed by pomona (18.1%) and tarassovi (9.9%). Seroreactivity to icterohaemorrhagiae and pomona were associated (P<0.05) with impaired reproductive performance (and substantial economic loss). Seroreactivity for pomona was associated (P<0.05) with stillborn piglets and mummified fetuses, whereas seroreactivity to icterohaemorrhagiae was associated (P<0.05) with the number of piglets born dead.

FREQUENCY OF ANTI-LEPTOSPIRES AGGLUTININS IN SOWS FROM A SWINE HERD IN THE IBIÚNA MUNICIPALITY, STATE OF SÃO PAULO, BRAZIL

ABSTRACT A serologic survey was conducted among 164 sows from a single farrow-to-finish swine herd located in the Ibiúna municipality, state of São Paulo, Brasil, to determine the frequency of antileptospires agglutinins. For detection of anti-leptospires antibodies, the microscopic serumagglutination test (MAT) was carried out using live cultures of 22 pathogenic and two saprophytic Leptospira spp. serovars. The most frequent serovar was found crossing the results of frequency and titer of agglutinins, and sera presenting equal titers for two or more serovars were not considered for this analysis. Of the 164 sows, 27 (16.5%) were seropositive for at least one Leptospira spp. serovar. The most frequent serovar was Hardjo (Hardjobovis), with 13 (54.2%) reactant sera. Other reactant serovars and respective frequency were: Shermani (16.6%), Bratislava (12.5%), Autumnalis (12.5%) and Icterohaemorrhagiae (4.2%).

The impact of Leptospira seropositivity on reproductive performance in sows in southern Viet Nam

A serologic survey was conducted among sows in the Mekong delta in southern Viet Nam to investigate associations between leptospiral seropositivity and reproductive performance. Data were collected from a total of 339 sows in lactation or gestation, from four large-scale state farms on three occasions. The seroprevalence for Leptospira interrogans serovar (sv) autumnalis was 32%, for L. interrogans sv bratislava 29%, for L. kirschneri sv grippotyphosa 13%, for L. interrogans sv icterohaemorrhagiae 27%, for L. interrogans sv pomona 5%, and for L. borgpetersenii sv tarassovi 13%. The reproductive parameters number of days from weaning to service (WSI), number of piglets born, number of piglets born dead, and number of piglets born weak, were evaluated. Seropositivity for sv tarassovi was associated with 0.8 more dead piglets per litter (P = 0.06), and sv grippotyphosa with a 1 day longer WSI (P = 0.06). There were no significant associations between reproductive performance and sv autumnalis, sv bratislava, sv pomona, and sv icterohaemorrhagiae. It is concluded that seropositivity for Leptospira can be associated with impaired reproductive performance even in areas where a high degree of immunity among sows is expected.

Serological survey of leptospirosis in sows with premature birth and stillbirth in Chiba and Gunma prefectures of Japan

In 1996 and 1997, the seroprevalence against Leptospira in parturient sows with premature birth or stillbirth from two herds was investigated. In three out of four sow serum samples obtained in Gunma Prefecture, the antibody titers to Leptospira interrogans serovar copenhageni (M20) were higher than 10,000 (the reciprocal of the serum dilution). Furthermore, the antibody titers to L. interrogans serovar canicola (Hond Utrecht IV) were significantly high in the three sows and the titers ranged from 1,000 to 3,000. In sows obtained in Chiba Prefecture, significantly high antibody titers to serovar copenhageni (M20) were confirmed in eight out of 40 sows, and antibody titers greater than 10,000 in six of them. Significantly high antibody titers to L. interrogans serovar icterohaemorrhagiae (RGA) and L. canicola (Hond Utrecht IV) were confirmed in four and 18 out of the 40 sows, respectively, compared with the titers to the other serovars. These findings may indicate the prevalence of leptospirosis in pig herds in both Gunma and Chiba Prefectures.