veterinary pathology(special path)

                     SUMMARY OF BACTERIAL DISEASES (VETERINARY PATHOLOGY)

BACTERIA:this is a micro-organism that has affected both human and animals both in positive and negative way; positvely some bacteria organism are found in the rumen of ruminant animals and help in the digestion and fermentation of the cellulose.Also in human it has created way for the emergence of penicillin..negatively it has caused some emergencies to health. below are some of the emergencies:

  • TUBERCULOSIS: This is a disease condition caused by the organism mycobacterium tuberculosis.this condition is characterized by the formation of tubercular granuloma.
                                                  SOME OF THE STRAINS                                                                               ( mycobacterium tuberculosis)that affect humans and other animals.                                             (mycobacterium bovis)that affects cattle and other ruminants                                                       (mycobacterium avium)that affects birds
                                                                                                                                                                                                                           TRANSMISSION
       Through inhalation of the organism.
       Through ingestion of the organism



                                                  PATHOGENESIS 
When inhaled,there is formation of primary tubercle in the lung usually in the diaphragmatic lobe.This infection if eliminated/overwhelmed by the body will lead to scar tissue formation.Therefore sensitizing the animal against any tuberculosis infection.but if the organism overwhelms the body,the infection will migrate along the respiratory tract,trachea and bronchi llymph node leading to secondary tubercle formation and may protrude into the bronchi,rupture and discharge into the lumen thus resulting to tuberculous pneumonia.
When bacilli discharged into the respiratory passages are coughed up and swallowed,the digestive system is infected.
Also it can enter the blood if the vein is ruptured thus reaching other body part.

                                                     CLINICAL SIGNS
1. Weakness.
2. Anorexia
3. Dyspnea
4. Emaciation
5. Enlarged lymph node
6. Fever
                                                             GROSSLY
1. Formation of tubercle that is firm,white or grey that is found in soft tissues like lungs and liver.
2. It gives a gritty sound on section.
3. It has a caseous necrotic center .
                           
                                                    MICROSCOPICALLY
1.The tubercle contains the bacilli.
2. The organism is surrounded by inflammatory cells (neutrophils & epitheloid cells)
                                                     
                                                     DIAGNOSIS
Use of tubercline test,identification of the organisms in excretions and exudates and also identification of the organism at necropsy.

  • PARATUBERCULOSIS (JOHNE'S DISEASE)
This is a wasting disease caused by the organism mycobacterium paratuberculosis.It is characterised by intractable diarrhoea with resultant dehydration,emaciation,wasting and eventually death.
It affects mainly sheep, cattle and goat.The lesions are commonly limited to the intestinal tract and its lymph node.But occassionlly,the spleen,lungs,kidney,uterus,placenta and liver are affected.

                                                         GROSSLY
1. There is thickness of the intestinal wall.
2. There is oedema of the intestinal mucosa
3. The intestinal wall appears corrugated.

                                                   MICROSCOPICALLY
1. There is presence of multinucleated epitheloid cell in the intestine.
2. There may be oedema of the intestine.
                                         
                                                   DIAGNOSIS
It can be diagnosed using the gross lesion and blood smear or tissue section.

  • CONTAGIOUS BOVINE PLEUROPNEUMONIA
This is a contagious pneumonia of cattle followed by pleurisy.It is caused by the organism micoplasma mycoides.
                                                  TRANSMISSION
It is transmitted through the inhalation of infectious droplets coughed out by infected cattle.
                                                 
                                                   CLINICAL SIGN
1. Anorexia
2. Dyspnea
3. Fever
4. Chest pain
                                                   GROSSLY
1. Presence of hydrothorax with fibrin flakes
2. Solidification and marbling of affected lungs
3. There may be sequestration and fibrinous pluera adhesion
                                                 
                                                   MICROSCOPICALLY
There is fibrinous pneumonia
There is thrombosis of pulmonary vessels
There is necrossis of lung tissue and oedema of interstitials

                                                     DIAGNOSIS
It can be diagnosed base on clinical signs and identification of organism in the pleura fluid.


  • ACTINOMYCOSIS
This is a disease of cattle and humans.It is caused by the organisms actinomyces bovis (cattle) and actinomyces isreali (human).It is characterised by hardening and irregular enlargement of the mandible and to a lesser extent the maxilla thus the name (lumpy jaw).

                                                      GROSSLY
There is hard and irregular enlargement of the jaw.
The lesion is white and glistering
Enlarged bone is honey combed
                                                       MICROSCOPICALLY
There are separate columns of the organisms that appear as rosettes

                                                        DIAGNOSIS
It is based on gross lesions and microscopic examinations.


                               
                                                 





Comments