6 de septiembre de 2021
El siguiente es un abstracto que Googled de principios del siglo 20, que describe la patología de la necrobacilosis, en esos días, aunque es en ingles, nos indica claramente el problema que se muestra en la fotografía. Yo creo que lo que debe quedar claro con la etiología de estos problemas, en las patas de ganados explotados en pastoreo o semipastoreo en el "trópico húmedo", es lo siguiente:
1) B. nechroporus y otras especies de esta familia que causan necrosis de los tejidos y (o) cuadros clínicos que involucran susceptibilidad a las toxinas que esta bacteria produce.
2) B. nechroporus es un "anaerobio obligatorio",
3) Es bastante resistente a antisépticos.
4) Temperatura ideal de cultivo entre 30 a 40 gradas centígrados, condición que se cumple muy bien en el "trópico".
5) Siempre deberá haber una "puerta de entrada" en las mucosas, órganos o piel afectados, que ha sido alterada o lesionada en alguna manera.
6) Olor característico de las lesiones resemblando al olor de una combinación de "queso y pegamento".
PATHOLOGIC PHYSIOLOGY.
Necrobacillosis is always an inoculation disease—that is to say,the necrosis bacillus requires for its entrance into the body an im-paired tissue; for the skin necrosis, any of the many likely breaks inthe cutaneous surface, pressure of harness, burns, sores of any kind;for the hoof necrosis, tread, punctured wounds, suppurating corns,etc.; for necrotic stomatitis, eruption or shedding of teeth, penetra-tion of the mucous membrane by a sharp-pointed particle of food;for necrosis of the genital tract, even the slight abrasions of themucous membrane common in normal, easy labor, may become themeans of infection. At the point of entrance the system recognizesthe presence and multiplication of the bacilli by a reaction markedby congestion and reddening, followed by an exudation rich inalbuminoids or fibrin-forming substances^ and a defensive immigra-tion of leucocytes.The metabolic products of the bacilli are exceedingly poisonous,killing everything with which they come in contact. Hence thefirst effect of the organism is a necrosis, or death, of the superficiallayer of tissue cells and leucocytes at the seat of invasion. The cellseither suffer fragmentation of their nuclei or become transformedinto irregular flaky masses—the so-called hyaline masses. Thisconstitutes1 superficial erosion of the tissue. The process never stopshere, though we may often recognize this stage in numerous recentfoci of necrosis in a rapidly spreading form of the disease.The second alteration is the production of false membrane by acombination of coincident changes. On the one hand, the necrosedtissue elements, having lost their nuclei and finer structure, are de-prived of their normal granulation and striation and take on a scalyappearance, being converted into hyaline substance. the albuminous exudate in which these dead cells are bathedprecipitates fibrin or coagulates into fine threads. This is knownas coagulation necrosis. There is thus formed a false membrane,the result of coagulation necrosis of the inflammatory exudate andthe entanglement in its meshes of the hyaline degenerated tissue cellsand leucocytes. This gives a grayish compact mass, more or lessadherent to the underlying tissue which, by failure of the dead cellsto be thrown off, may be built up an eighth of an inch or so.The third alteration connected with this process is due to an inva-sion of the deeper tissues. The bacilli are always found on the borderline between the living and dead tissue. Here, in great bundles ofbeaded filaments, they may be seen attacking the healthy tissue,which in turn has erected against the attack a wall of leucocytes,while masses of micrococci, tangles of streptococci, and clumps ofbacteria are lodged in the superficial layers. Thus the process iscarried down into the deeper tissues, forming ulcers and fistuloustracts of varying depth. By the coagulation necrosis occurring inthe region of the blood vessels they become obstructed by pressureor sometimes by thrombosis, and thus the dead tissue becomes avas-cular, and the necrotic mass undergoes pulverization into finer andminuter particles until it is a dry, crumbly, yellowish mass of tissuedetritus resembling cheese.
