But in the beginning, considered identical to the man and mammalian tubercle bacilli of the birds, while other researchers (Maffucci, Strauss and Gamaleia) called attention to the particularities of the bacilli of tuberculosis of the past. 

R. Koch cambió, entretanto, de opinión; mas otros investigadores, al frente de ellos Romer y M. Koch y Rabinowitsch (1907), siguieron creyendo que los bacilos de la tuberculosis de las aves eran idénticos a los de la tuberculosis del hombre y mamíferos.

 Since they had managed to infect experimentally hens with material sick of people and of animals, mammals and isolate in pure culture for acid-fast bacilli of tuberculosis, avian alterations-tuberculous mycobacteria.

This idea was later abandoned, due to the fact, that in hens exempt from all tuberculosis infection, as evidenced by the test tuberculínica, the experimental infection by tubercle bacilli of human or bovine occurred only in the worst case, alterations, local cured, but never injury-tuberculous mycobacteria such as those presented in the tuberculosis spontaneous fowls (Tschebnitz 1923, Richter, R. Eber, and others). 

It was found, furthermore, that the bacilli of tuberculosis of birds may produce alterations of tuberculosis in pigs (O. Bang, Mohler and Washburn), and, in isolated cases, in other mammals.

Location:

Tuberculosis of the poultry occurs with some frequency and cause sensitive losses in poultry houses and dovecotes. It is also observed in other avian (turkeys, guinea fowl); instead, it is exceptional in waterfowl.

Exotic birds, such as parrots, canaries, and similar species, are also frequently affected. It is also occasionally observed in wild birds (partridges, pheasants, capercaillies, grouse, choughs, etc.).

The apparent recent increase in the incidence of avian tuberculosis appears to be linked to the poor housing and hygiene conditions in which many poultry are kept in cities. However, the disease is not uncommon on small rural farms either, where it likely spreads widely because the birds are often slaughtered only at an advanced age.

In contrast, in large-scale farms poultry the degree of infection decreases from that, lately, they tend to sacrifice the breeding birds in the meet 2 years of age and will keep the pups away from the adult birds. 

Ethology:

Tuberculosis in poultry is caused by the avian tuberculosis bacillus (the gallinaceous type of the tuberculosis bacillus). Only in pet birds is tuberculosis most often caused by human tuberculosis bacilli. 

Infections occasional poultry by bacilli of tuberculosis, human or bovine, even when operating, lack of practical importance, since at most produce alterations in local and prone to healing.

Natural infection:

Usually occurs by ingestion of organs of tuberculosis or deletions of sick birds. It is also produced by wounds of the oral mucosa and of the skin, and it is not impossible to infection by the respiratory tract.

The infectious agent is usually introduced into healthy poultry houses by poultry infected with tuberculosis or by material contaminated with bacilli-containing excretions from such animals.

Tuberculosis bacilli are found relatively frequently in the eggs of tuberculous chickens (according to Fitch, Lubbe, Husen, and Dykmans 1928, up to 1% of eggs from chickens that simply react to tuberculin should be considered infected). Ten days after infection, the bacilli may already have settled in the ovary so that, from this point on, the hens usually lay infected eggs (Raebiger 1929).

Despite this, the infection germination would have no great importance, since the eggs or infected do not develop embryos (Fitch and Lubbe Husen 1924, F. Schmidt) or, if they develop, the chicks die immediately (Baumgarten). In practice, the infection by eggs that contain bacilli can only happen when you feed the birds with raw eggs.

Según Scheible (1950) y otros, en la mayor parte de los casos pueden encontrarse bacilos también en la sangre y en la carne de las aves muertas o sacrificadas a causa de su reacción positiva a la prueba de tuberculina, los cuales pueden ser motivo para el contagio de gallinas.

In the pens infected, the chances of contagion, and the number of cases depend on of the conditions in which they have birds, as the lack of cleanliness and the crowding of the averío in local small and little care favor infection.

The age at which birds suffer from tuberculosis also depends on local conditions. In large breeding farms, where chicks are isolated from adult birds for some time, cases of tuberculosis do not usually occur in birds less than 1 year old; however, in small chicken coops where chicks are in contact with adult birds with tuberculosis from the outset, the disease is already observed in young birds.

Even on small farms, the number of cases of illness and death increases with age.

Poor hygiene conditions and, above all, inadequate nutrition influence the course of the disease, since in well-maintained pens, weight loss in birds due to tuberculosis is usually observed at a later age than in poorly fed flocks.

Pathogenesis:

Once tuberculosis bacilli reach the digestive tract, they penetrate through the lymphatic follicles of the pharynx or intestine into the deeper layers of the tissues, regardless of whether or not they have caused pathological changes in the digestive tract.

They enter the bloodstream and are carried by the blood to various organs, particularly the spleen, liver, bones, etc., where they cause tuberculous lesions.

Tuberculosis in birds always begins with bacteremia, which, in severe infections, can occur as early as 2 to 3 days later (Raebiger).

As the disease progresses, the bacilli from the foci formed in the manner described may temporarily enter the bloodstream and reach organs that have not yet been affected. In addition, tuberculosis bacilli reach the liver not only via the bloodstream but also through the lymphatic system.

In the rare cases in which the infection occurs through the respiratory tract or cutaneous wounds, the primary focus develops in the lungs or on the skin, where it then the bacilli enter also in the way blood count and go with the blood to the organs more diverse.

The demonstrations caquécticas, which ensue in advanced cases, are the result of the toxic action of the chemicals of the bacillus and the tissues destroyed. The death ensues, he prays as a result of cachexia, prays for internal bleeding, particularly of the liver and spleen.