Detection of leptospires in clinically healthy piglets born from sows experimentally infected with Leptospira interrogans serovar Canicola

Abstract

Leptospirosis is an important zoonosis that causes reproductive disorders in swine. The isolation of leptospires from aborted fetuses, stillbirths and weak piglets was obtained in several occasions, however, the bacteria was never isolated from apparently healthy piglets born from apparently healthy infected dams. Six sows of the Landrace breed with a known date of service and pregnancy confirmed by ultrasonography were infected intravenously with 5 ml of Leptospira interrogans serovar Canicola inoculum between 76 and 90 days of gestation, and one week after farrowing, at least one piglet per sow was euthanized and samples of liver, kidneys, lungs, heart, spleen and gastric content were taken and examined by PCR. Reproductive disorders or any clinical sign of infection were not observed in the inoculated sows. The piglets born from these animals presented no clinical signs or macroscopic lesions that could be attributed to leptospirosis. All inoculated sows presented anti-leptospires antibodies by microscopic serum-agglutination test (MAT) in the postinoculation serum samples and leptospires were not found in the urine as well as were not detected by PCR applied in this material, however, PCR accomplished in kidneys and liver from a euthanized sow presented positive results. Of the total of 12 euthanized piglets, 10 (83.3%) presented positive results by PCR in at least one of the kidney, liver, heart, spleen, lung and gastric content samples. The present study reports the vertical transmission of the infection and the detection of leptospires in clinically healthy piglets born from experimentally infected sows, which is important of the epidemiological point of view as the maintenance of clinically healthy infected animals may allow the persistence of the bacteria in the herd, exposing other animals to the risk of infection.

Cross-Species Surveillance of Leptospira in Domestic and Peri-Domestic Animals in Mahalla City, Gharbeya Governorate, Egypt

“…26,27 Almost all of the surveyed black rats were infested with ectoparasites, which may have directly or indirectly allowed for the percutaneous entry of leptospires. Rats with traumatic skin injuries had slightly higher positivity rates than animals without injuries: 22% versus 15%, respectively.…”

Laboratory investigation of adult small ruminant Leptospirosis, a neglected infection in Greece: problems and recommendations

“…One such method is isolation, but due to its time limitations and the time required for examining a second serum sample, various PCR versions have been established for quickly confirming clinical leptospirosis (Gravenkamp et al, 1993;Bomfim and Koury, 2006;Lilenbaum et al, 2008;Lilenbaum et al, 2009). However, comparisons between PCR, culture and serologic results are not always satisfactory (Faber et al, 2000;Soto et al, 2006;Barbante et al, 2014), if infecting serovars are not included in the MAT testing. In such cases, PCR could be positive, but the MAT negative.…”

Leptospirose Suína

“…No Estado de São Paulo, AZEVEDO et al (2006), em uma granja de suínos com 164 fêmeas, encontraram 16,5% soropositivas para pelo menos um sorovar de uma coleção de 24 testados, e os mais freqüentes foram: Hardjo (Hardjobovis), com 54.2% aos animais sororeagentes. Outros sorovares reagentes e suas respectivas freqüências foram: Shermani 16,6%, Bratislava 12,5%, Autumnalis 12,5% e Icterohaemorrhagiae 4,2%.…”

“…Quando a infecção acontece durante o terceiro trimestre de gestação, pode ocorrer produção de anticorpos específicos que, ocasionalmente, superam a manifestação da doença (BASTOS, 2006;BORDIN, 1992;CORREA;CORREA, 1992;DANNEMBERG et al, 1975;EDWARDS, 1979;FAINE, 1982;ROSE, 1966). SOTO et al (2006), em fêmeas suínas desafiadas com Leptospira interrogans, sorovar Canicola, relataram a transmissão vertical da leptospirose suína com o nascimento de leitões saudáveis e identificação da positividade pela técnica de PCR em diversos órgãos destes animais.…”