University of Wisconsin–Madison

JD in Mexican Sheep

Researchers in Mexico surveyed sheep flocks in the state of Aguascalientes in Mexico. Their findings were published in Abanico Veterinario.


With the objective of identifying the presence of Paratuberculosis (PTB), an infectious disease caused by Mycobacterium avium ssp paratuberculosis (MAP), in sheep, through pathological studies, bacterial culture and IS900 PCR, as well as estimating seroprevalence to MAP. The present cross-sectional study, was conducted in 16 different flocks, with the serum of 2415 adult sheep, and analyzed by Enzyme-Linked ImmunoSorbent Assay (ELISA); nine sheep were used with clinical signs suggestive of PTB, from which samples were obtained for the identification studies; obtaining 51.3% of animals seropositive to MAP (1239/2415), in 100% of the herds (16/16); Bacterial isolation and its identification by PCR IS900 were founded in five of the nine cases (5/9) corresponding to 31.25% of the herds (5/16). Confirming the presence of Mycobacterium avium ssp paratuberculosis, and a high frequency of seropositive animals to MAP in flocks of Aguascalientes.


Con el objetivo de identificar la presencia de Paratuberculosis (PTB), enfermedad infecciosa causada por el Mycobacterium avium subsp paratuberculosis (MAP), en ovinos, a través de estudios anatomopatológicos, cultivo bacteriano y PCR IS900, así como estimar la seroprevalencia a MAP. El presente estudio, de tipo transversal, se realizó en 16 diferentes rebaños con el suero de 2415 animales adultos y analizados por Ensayo por Inmunoabsorción Ligado a Enzimas (ELISA); se emplearon nueve ovinos con signos clínicos sugerentes a PTB, de los cuales se obtuvieron muestras para la realización de los estudios de identificación; obteniendo un 51.3 % de animales seropositivos a MAP (1239/2415), en el 100% de los rebaños (16/16); el aislamiento bacteriano y su identificación por PCR IS900 en cinco de los nueve casos hallados (5/9) correspondiendo al 31.25% de los rebaños (5/16). Conformando la presencia del Mycobacterium avium subsp paratuberculosis, así como una elevada frecuencia de animales seropositivos a MAP en rebaños de Aguascalientes.


Johne’s disease is far more common than most sheep owners realize. Biosecurity regarding animal purchasing is critical to prevention of this economically important disease. This is especially true for sheep breeders. MAP infection prevention is far less costly than MAP infection control. In other words: PREVENTION PAYS. Sheep breeders should only buy animals from flocks that are 100% negative by fecal PCR. Breeders that don’t follow this practice will eventually have sheep that look like the one shown above from publication and then spend years and a lot of money trying to eradicate the infection.