World Veterinarian Quiz 36

GLANDERS

·  World Organization for Animal Health (OIE)-notifiable disease

·        ·  Glanders is acute, chronic and fatal contagious zoonotic disease which is most common seen in Equidae family like horses, mules and donkeys. characterised by developing ulcerating nodules at Skin, part of upper respiratory tract and Lungs

·        ·  Glanders has been eradicated from most countries, except for some areas in North Africa, Asia, and Eastern Europe.

Synonyms:

·        ·  Farcy

·        ·  Malleus

·        ·  Droes

ETIOLOGY:

Burkholderia mallei

·        ·  Gram-negative rods

·        ·  Non-encapsulated and non-spore-forming

·        ·  Obligate aerobes, destroy by heats, lights and disinfectants

·        ·  Oxidase-positive and catalase positive.

·        ·  Non-motile.

·        ·  It requires 1% glycerol in media for optimal growth.

HOST:

·        ·  Horses, donkeys, and mules.

·        ·  Natural disease occurs in Carnivores (dog, cat and lion), sheep and goats.

·        ·  Cattle and pigs are considered more resistant.

·        ·  Humans are susceptible and infection can be fatal.

·        ·  Glanders organisms can be used as bio-terrorist threat.

·        ·  Glanders is a zoonotic disease

RISK FACTORS:

·        ·  Stressed animals and those animal which doing activity of  heavy work

·        ·  Poorly fed

·        ·  Animal kept in poor environment are more susceptible

PATHOGENESIS

Ingestion of contaminated feed and water by animal 

⇓

Bacteria penetrate the mucosa and spread via lymph vessels to regional lymph nodes, bloodstream hematogenouslyInternal organs, particularly the lungs.

⇓

Virulence factor that Allow bacterium to enter in to phagocytic cell and non phagocytic cells via

⇓

1) Phagocytosis allow to cross mucosa barrier

2) Endocytosis react to BALT (bronchus-associated lymphoid tissue) /MALT (mucosa-associated lymphoid tissue)

·        Glanders is characterized by ulcers in nasal passage, miliary nodules in lungs, edema of lymph nodes, lymphangitis and lymphadenitis.

SOURCE OF INFECTION  

Exudate can be act as source by

ü     Contaminate The Food And Water – Ingested By Susceptible Animal – Disease

ü  By The Contaminate Mucous Membrane And Skin Abrasions

ü  By Contaminate Harnesses And Grooming Tools

TRANSMISSION

        i.          ·    Infected Animals And Carriers

     ii.            ·  Vertical Transmission ( Mare – Foal)

   iii.            ·  Venereal Transmission ( Stallion – Mare )

   iv.            ·  Fomites Able To Spread B.Malli

      v.            ·  By Inhalation In Rare Cases

CLINICAL SIGNS:

·        Clinical cases are often a combination of the three forms, and may be acute (or subacute), chronic or latent.

1. Nasal and 2. pulmonary forms                      

ü       Acute In Nature                                                            

ü        Seen In Donkeys And Mules                                   

3.   3. Cutaneous form:

      Chronic In Nature

      Seen In Horse 

1) NASAL FORM:

·        Fever

·        Anorexia (appetite loss )

·        Dyspnoea

·        Coughing  

·        In early stage: unilateral serous nasal discharge     

·                             Unilateral, with copious, purulent, green-yellow nasal exudate.

·        Bilateral or unilateral Enlargement of regional lymph nodes likes submaxillary

2) CUTENOUS FORM (farcy):

·      ·    It is chronic form of Glanders

·       ·  Initially shows fever , coughing , enlarged lymphnode , dyspnoea

·      ·    Skin showing multiple nodules along the course of lymphatic vessels

·      ·    Due to trauma or pressure nodules gets ruptured and oily , thick yellow exudate comes out

·       ·  Thickened fibrous lymph vessels radiate from the lesions and connect one to the other

·       ·  This form associated with longer period of exacerbation leads to debilitation.

3) PULMONARY FORM:

 ·        Fever,

 ·       Laboured breathing

 ·        Epistaxis

MACROSCOPIC LESION :

1)    PULMONARY FORM:

·               ·  Lung : generalized pinpoint to 2-cm diameter pyogranulomatous nodules throughout the lung,

·        ·  Pharynx, larynx, and trachea : pyogranulomatous ulcerative lesions

·        ·  Catarrhal bronchopneumonia

·         · Bronchial lymph nodes : enlarged 

2)    CUTENOUS FORM (farcy):

·        ·  Chains of nodules or ulcers that follow lymphatic vessels, and represent purulent lymphangitis with extensive leukocyte necrosis.

·        ·  Infected lymphatics may result in swollen, thickened, cord-like lesions o coalescence of lymphatic lesions resemble a string of beads : “farcy pipes’’

3)    NASAL FORM:

·       ·  Nasal cavity : pyogranulomatous nodules in the submucosa

·       ·  Ulcerative lesions in conchal mucosa heal and are replaced by star-shaped fibrous scars.

 MICROSCOPIC LESIONS

·        Nodules :  

ü    ·    Centrally aggregation of neutrophils

ü    ·    Peripherally epithelioid macrophages and fibrosis.

ü    ·    The relative proportions of neutrophils, macrophages, fibrosis, and mineralization are variable.

ü    ·   Infiltration of neutrophils in and around necrotic foci in liver, kidneys and intestines

DIAGNOSIS

·          · Base on Clinical signs

·         · Mallein test

·         · Sensitive, specific test use to diagnose advanced clinical cases of horse.

1)   1.  Intradermo palpebral test :

ü      · Specific, more reliable , sensitive test

ü      · 0.1ml of PPD mallein injected inradermally in lower eyelid

ü      · After 24-48 hrs mark results

ü         Positive : swelling of eyelid , purulent discharge from eye , rise in temperature

ü         Negative : no reaction , some time little swelling of lower eyelid

2)    2. Ophthalmic test :

ü  Place drops of mallein PPD into eye

ü  Positive animal shows selling of eyelid and side of face , discharge from eyes

3)    3. Subcutaneous test :

·        Requires subsequent serological diagnosis

·        10cm square area in middle of neck : clipped and disinfect

·        2.5ml mallein PPD injected subcutaneously

·        Record the temperature of animal

·        Positive animal : pyrexia  

During 15hrs of injection : painful firm swelling , raised edges

·        Negative animal : No swelling

Serological tests:

·         · ELISA

·         · CFT

·         · Immunoblot,

·         · Rose bengal test,

·         · Indirect hemagglutination,

·         · Agar-gel immunodiffusion,

·         · Indirect fluorescent antibody testing,

·         · Animal inoculation :

·        Hamsters , Guinea pigs and cat have been used

·        Inoculation of infected materials intraperitoneally in male guinea pig.

·        Positive material shows peritonitis, orchitis in male guinea pig.

 

DIFFERENTIAL DIAGNOSIS

·        · Melioidosis

·        · Strangles

·        · Epizootic lymphangitis

·        · Sporotrichosis

·        · Lymphangitis

·        · Trauma and allergy

·        · Guttural pouch empyema

·        · Botryomycosis

·        · Tuberculosis

TREATMENT:                               

Antibiotic like…

·        · Enrofloxacin (4 - 8 mg/kg IV) and

·        · Trimethoprim–sulfadiazine (32 mg/kg IV)

·       · Doxycycline

 · Treatment can be used in endemic regions but that leads to sub-clinical carrier animal that can be infects humans and other animal

References:

Pathologic Basis of Veterinary Disease Expert Consult

6th edition

By: James Zachary, M. McGavin