[Retrospective seroprevalence study of bovine leptospirosis in Mexico considering the ecological regions]. / Estudio retrospectivo de seroprevalencia de leptospirosis bovina en M'exico considerando las regiones ecológicas.

The newly published information about the different ecological regions of Mexico was analyzed aimed at knowing the situation of bovine leptospirosis. A bibliographical search was made and the articles were chosen according to the following inclusion criteria: a) diagnosis technique: microscopic agglutination, b) positive criterion titres of 1:100 or higher, c) time period: 1991-2003, d) publications such as thesis, memoirs of congresses, non-scientific journals and journals with arbitrage, e) location by states. The duplicated information was considered as the exclusion criteria. The results of frequency and of serovarieties of leptospirosis were reported by state, considering the different ecological regions. Reference to 17 states is made. The arid and semi-arid region had a frequency of 37.8 % with a range from 31% to 59%, the prevalent serovars were H-89 strain (hardjo genotype hardjoprajitno), hardjo, wolffi and tarassovi. In the dry tropical region, there was a frequency of 45.9 % with a range from 27 to 72 %. The prevailing serovarieties were wolffi, hardjo and tarassovi. In the humid tropical region , the frequency was 63.8 % with a range between 31.7 and 84.6 %. The predominating serovarieties were H-89 strain (hardjo genotype hardjoprajitno), hardjo, wolffi and tarassovi. In the mild climate, the average frequency of leptospirosis was 39.4 % with a range from 22.1 to 54.3 %. The prevailing serovarieties were Palo Alto strain (icterohaemorrhagiae), Sinaloa ACR strain (portlandvere), bratislava, pyrogenes, pomona, and H-89 strain (hardjoprajitno), hardjo, wolffi and tarassovi. It was concluded that the presence of antobodies against L. interrogans is endemic in the different ecological regions of Mexico and that there is an elevated prevalence of serovarieties hardjo, wolffi y tarassovi; although in the temperate region, the Palo Alto strain (icterohaemorrhagiae), the Sinaloa ACR strain (portland vere) and Bratislava are present, too. Apparently, the climate influences on the frequency of presentation of the serovarieties. This is the first analysis of bovine leptospirosis by regions made in Mexico.

[Evaluation of an homologous bacterin against bovine leptospirosis]. / Evaluación de una bacterina homóloga contra la leptospirosis bovina.

48 adult bovine females dividided into 6 groups were used aimed at characterizing the immune response induced in breastfeeeding cows by an homologous bacterin formulated with different adjuvants. They were intramuscularly administered 2 milliliters of a bacterin formulated with Leptospira interrogans serovars uam, wolffi, hardjo, bratislava, grippotyphosa and panama added with different adjuvants, such as aluminum hydroxide, Freud's complete adjuvant, Freud's incomplete adjuvant, liposoluble vitamins, bacterin plus disparasitization with levamisol. The control group was administred only with bacterin. Immunization took place in 2 occasions at a time interval of 28 days. Blood samples were taken every 7 days during the first month after vaccination, and every 28 days for the next 8 months. All the sera were analyzed by the microscopic agglutination test. The results were transformed into Log10 and they were analyzed by NLIN and GLM of SAS. The period of greater response was estimated by the prediction model (Wood). The bacterin did not produce alteration either in the physiological constants, or in milk production. The serovars of Leptospira interrogans that induced higher titers were uam, hardjo and wolffi. The statistical difference between treatments and between serovars was determined.