Isolation of leptospira Serovars Canicola and Copenhageni from cattle urine in the state of Paraná, Brazil / Isolamento de leptospiras dos Sorovares Canicola e Copenhageni em amostras de urina de bovinos no estado do Paraná, Brasil

In 2001, 698 urine samples were randomly collected from cattle at a slaughterhouse in the State of Paraná, Brazil. Direct examination using dark field microscopy was carried out immediately after collection. Five putative positive samples were cultured in modified EMJH medium, yielding two positive cultures (LO-14 and LO-10). Typing with monoclonal antibodies revealed that the two isolates were similar to Canicola (LO-14) and Copenhageni (LO-10). Microscopic agglutination test results show that Hardjo is the most common serovar in cattle in Brazil. Rats and dogs are the common maintenance hosts of serovars Copenhageni and Canicola. The excretion of highly pathogenic serovars such as Copenhageni and Canicola by cattle can represent an increasing risk for severe leptospirosis is large populations, mainly living in rural areas.

No ano de 2001, 698 amostras de urina foram colhidas aleatoriamente, durante o abate em um frigorífico do Estado do Paraná, Brasil. O exame direto em microscópio de campo escuro foi realizado imediatamente após a colheita. As cinco amostras de urina positivas neste exame foram semeadas em meio EMJH modificado, sendo possível o crescimento de leptospiras em duas (LO-14 e LO-10). As estirpes isoladas foram tipificadas, por painel de anticorpos monoclonais, como mais similares ao perfil das amostras de referência dos sorovares Canicola (LO-14) e Copenhageni (LO-10). No Brasil, inquéritos sorológicos utilizando a prova de soroaglutinação microscópica mostram o predomínio de reações para o sorovar Hardjo em bovinos. Roedores e cães são os reservatórios mais comuns dos sorovares Copenhageni e Canicola, respectivamente. A eliminação dos sorovares Canicola e Copenhageni pela espécie bovina pode resultar em um aumento na ocorrência de casos graves de leptospirose humana, principalmente na população rural.

[Use of diafiltration in the lavage of cultures of Leptospira interrogans canicola canicola for the production of vaccine vax-SPIRAL]. / Empleo de la diafiltración en el lavado de cultivos de Leptospira interrogans canicola canicola para la producción de la vacuna vax-SPIRAL.

It was proposed to substitute the present technology of the lavage operation for a tangential microfiltration system at the lavage stages of the culture of Leptospira interrogans canicola canicola. It was proved that this system may be applied, since no cellular affectation was observed and high pollutant elimination levels were obtained.

Hemolysin production by Leptospira interrogans serovar canicola in a protein-free medium with hemin.

Leptospira interrogans serovar canicola strain moulton was grown to a high cell density in a protein-free medium. When hemin was added to this medium, hemolysin was produced. Hemolysin was not detected when other porphyrins or cytochrome C were substituted for hemin in the medium.

Humoral immune responses of cattle vaccinated with leptospiral pentavalent outer envelope and whole culture vaccines.

The humoral immune response of cattle vaccinated with leptospiral pentavalent outer envelope and whole culture vaccines was monitored with the microscopic agglutination (MA) test and the leptospiricidal activity (LA) test for a 2.5-year period. The serovars present in the vaccines were canicola, icterohaemorrhagiae, grippotyphosa, pomona, and hardjo. The LA test had greater sensitivity than the MA test for detecting antibodies to the hardjo, canicola, and icterohaemorrhagiae components of the pentavalent vaccine and was approximately equal in sensitivity to the MA test for detecting antibodies to the grippotyphosa and pomona components of the leptospiral vaccine. Both IgM and IgG were produced in similar amounts in the immunized cattle, and both classes were reactive in the MA and the LA tests. The IgM class of antibodies was more reactive in the MA test, whereas the IgG class of antibodies was more reactive in the LA test. Using the MA test as the criterion of evaluating, the immunogenic potency of the individual vaccine components was found to be canicola more than icterohaemorrhagiae more than grippotyphosa more than pomona more than hardjo. A direct correlation between protective antibodies, as determined by the hamster passive protection test, and antibodies reactive in the MA and the LA tests was observed.

Cultivation of parasitic leptospires: effect of pyruvate.

Sodium pyruvate (100 mug/ml) is a useful addition to the Tween 80-albumin medium for the cultivation of parasitic serotypes. It is most effective in promoting growth from small inocula and growth of the nutritionally fastidious serotypes.

Growth of pathogenic Leptospira in chemically defined media.

A protein-free chemically defined medium for cultivation of pathogenic Leptospira was developed. The medium permitted continued serial subculturing of 9 serogroups (52 strains) of the 12 serogroups (61 strains) tested. Growth was initiated from small inocula, and the growth rate and maximal cell yields were similar to those on serum-containing media. The nutritional requirements of serogroups L. canicola, L. pomona, and L. grippotyphosa were studied in a basal medium composed of inorganic salts, a fatty acid, vitamin B(12), and thiamine. All strains tested utilized ammonium chloride as the sole nitrogen source. A fatty acid, vitamin B(12), and ferrous ions were essential. Growth was stimulated by thiamine, potassium, and calcium ions.