Portals of entry of Mycobacterium Tuberculosis

The pathogenicity occurs in the human b eing from the following portal of entry of infection

   1.. The respiratory tract –

A health man can be infected by droplet infection by sneezing and coughing by the patient with open type of tubercular lesion . This will  cause Pulmonary Tuberculosis . right lung is mainly affected because right bronchus is short and straight and apex of the right lung is commonly affected due to restricted movement of the apical part and slowing of blood and lymphatic flow .Different opinions have expressed for lung infection from tubercle bacilli .

  2.. The alimentary tract –

   Through mouth and nasopharynx , tubercle bacilli may enter into alimentary tract and after absorption through the intestinal mucosa , tubercle bacilli entr into the lymph channel and blood and cause enlargement of cervical gland s and Peyer’s patches of small intestine from where they can pass to mesenteric glands . From infected milk , they may come into intestine .

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3… The skin .

   Through minute abrasion  in the skin , tubercle bacilli  may enter into body . Primary tuberculosis  of skin usually takes following forms –

i)                    Lupus vulgaris

ii)                  Verruca tuberculosa .