World Veterinarian Prize Quiz - 2

ANTHRAX

⇨ It’s an acute widespread infectious disease of livestock that occurs throughout the world. It’s considered to be a very serious disease of herbivorous animals (Cattle, Buffalo, Sheep, and Goat) as well as also affecting human beings.

⇨ Anthrax is Zoonotic disease. It is potent bacteria use as a bioterrorism.

SYNONYMS:

⇨ Splenic fever

⇨ Milzbrand

⇨ Charbon

⇨ Wool sorter’s disease: is human because of inhalation of anthrax spore by human or workers in the wool and hair industries. Cutaneous anthrax is more common.

⇨ Tarka

⇨ Malignant Pustule

⇨ Malignant Edema

⇨ Ragpickers’ Disease

ETIOLOGY

⇨ Bacteria: Bacillus anthracis

⇨ It is Gram positive, Large rod shaped, non-motile, capsulated, aerobic, and spore bearing bacteria

⇨ Over 1,200 strains.

⇨ Two forms 1. Vegetative and 2. Spore

⇨ Spores are so resistant that it can keep bacterial organism viable for 60 years in a rubber stoppered bottle.

⇨ Sporulation of this bacteria requires an environmental temperature range between 12°- 42° C (53–107° F) and does not occur at temperatures below 9° to 12° C (48–53° F)           

⇨ McFadyean’s reaction :- the bacteria on staining with polychrome methylene blue shows blue appearance with pinkish discoloration around it .

⇨ B. Anthracis toxins produce three types of protein

1. Edema Factor (EF)

2. Protecting Antigen (PA)

3. Lethal Factor (LF)

⇨ If this all toxins EF, PA and LF are individual so safe for animal but when they are in combination so infected animal towards the death.

1. Protecting Antigen (PA) is binding with specific target cells and the introduction of LF and EF into these target cells.

2. Edema Factor (EF) is an adenylate cyclase that triggers the abnormal production of cyclic-AMP which causing altered ion and water movement so formation of edema and this is characteristic of anthrax.

3. Lethal Factor (LF) is a zinc dependent protease that disturb the regulatory pathways of eukaryotic cells which are associated with phosphorylation.

SUSCEPTIBLE HOST

⇨ Almost all mammals are susceptible.

⇨ More common in cattle and sheep

⇨ Less common seen in goat and horse.

⇨ Highly resistance in Dog, Cat and Pig.

⇨ Algerian sheep are reported as resistance of anthrax. 

 

MODE OF TRANSMISSION

⇨ Anthrax spores remain viable in soil for significant period of time. 

⇨ Contaminates bone meal or pasture.

⇨ Contaminated blood and other discharge of animals

⇨ Carnivores can spread the infection from one place to another.

⇨ Avian scavengers like gulls and Vulture also transmitted the anthrax.

⇨ Animals contaminated product like bone meal, fertilizer, hides, hair and wool.

⇨ Various flies, mosquitoes and ticks are also transmission of this disease.

PATHOGENESIS

Ingestion of spore or inhalation of spore or infection by micro wound on GI tract or infection by abrasion wound/skin lesion by biting flies.

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Entry the spores are transformed into vegetative form and move towards the lymph nodes.

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In the lymph nodes start the multiplication of the bacilli and enter the blood by way of lymphatic channel.

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The septicaemia condition is developed into host.

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The bacilli are invade into all the body tissues and Organs like spleen.

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Animal may die at this stage due to acute renal failure and shock.

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In cutaneous form the Organism gain entry through abrasions on the skin and localize in the skin and subcutaneous tissue.

CLINICAL FINDINGS AND LESIONS

1. Peracute: Ruminants (cattle, sheep, goats, antelope)

2. Acute: Ruminants and equine

3. Sub-acute/chronic: Swine, dogs, cats

Ruminants

1. Per acute

⇨ Sudden death

⇨ Staggering

⇨ Trembling

⇨ Dyspnea

⇨ Terminal convulsions, and

⇨ Death

2. Acute

⇨ It seen up to 2 days before death

⇨ Depression

⇨ Stupor

⇨ Disorientation

⇨ Muscle tremors

⇨ Dyspnea, and

⇨ Congested mucous membranes

⇨ Bloody discharges from the nose, mouth, and anus also observed in acute stage  

⇨ Subcutaneous edematous swellings at the part of the ventral neck, thorax, and shoulders region

3. Chronic (rare)

⇨ Pharyngeal and lingual edema

⇨ Subcutaneous edema of the ventrum including the neck, sternum and flank

⇨ Death from asphyxiation

Cutaneous Anthrax in Human

⇨ 95% human cases are cutaneous infections

⇨ 1 to 5 days after contact

⇨ Small, pruritic, non-painful papule at inoculation site

⇨ Papule develops into hemorrhagic vesicle & ruptures

⇨ Slow-healing painless ulcers which are covered with black eschar and surrounded by edema.

⇨ Infection may spread to lymphatics or local adenopathy

⇨ Septicemia may develop

⇨ 20% mortality in untreated cutaneous anthrax

Inhalation Anthrax in Human

⇨ Virtually 100% fatal (pneumonic)

⇨ Meningitis may be complicated cutaneous and inhalation forms of anthrax.

⇨ Pharyngeal anthrax

⇨ Fever

⇨ Pharyngitis

⇨ Neck swelling

GIT or Ingestion Anthrax in Human

⇨ Virtually 100% fatal

⇨ Abdominal pain

⇨ Hemorrhagic ascites

⇨ Paracentesis fluid may reveal gram-positive rods

Macroscopic pathology

⇨ Following death there is oozing out of blood from all the natural orifices of the body.

⇨ The blood used to containing number of anthrax bacilli.

⇨ In anthrax carcass decomposes rapidly and also seen formation of gas and distension of abdomen.

⇨ Rigor mortis is absent.

⇨ The blood that oozes out is Dark red or black in appearance due to lack of oxygen and does not clot rapidly.

⇨ The spleen is very much enlarged and soft or splenomegaly.

⇨ The liver and kidneys are congested, mucous membrane of intestine is intensely red,

⇨ There is prolapse of rectum and

⇨ Lungs are congested, swollen and oedematous.

DIAGNOSIS

⇨ Bloody discharges from the mouth, nostrils and anus must be suspected for animal was die due to anthrax.

⇨ Infected carcass should not be opened because of zoonotic prevalence.

⇨ Laboratory Examination 

⇨ Serological test:

✔️Ascoli's test:  is Thermo precipitation test à  this test is employed for the detection of anthrax in hide or tissue.

A piece of hide or tissue is boiled in water and an extract is obtained  à The clear floor thus obtained is layered on a very narrow precipitating serum.

⇨ If it is positive so we can find whitish ring appear at the junction of the two fluids.

⇨ Cultural examination: A loop full of suspected blood sample is to be streaked on 5% blood Agar and nutrient Agar plates and the plates are to be incubated aerobically for 18 to 24 hours at 37 degrees Celsius. Positive cases will show cultural characteristics like absence of mobility, very little or no haemolysis, medusa head appearance and inverted fur tree appearance on gelatine stab culture.

⇨ PCR

⇨ ELISA

DIFFRENTIAL DIAGNOSIS

⇨ Anthrax must be differentiated from

⇨ Lightning stroke

⇨ Black quarter

⇨ Hemorrhagic septicemia

⇨ Babesiosis

⇨ Acute lead poisoning and

⇨ Snake bite

TREATMENT

⇨ Anthrax bacilli are sensitive to penicillin drugs and other broad spectrum antibiotics.

⇨ In all cases the treatment has to be continued for five to Seven days. Where the disease is continuing prophylactic treatment with long active antibiotics is recommended

⇨ Inj. Penicillin G sodium/potassium (20,000 IU/kg IV every 12h at least as loading dose IV)

 ⇨ Inj. Procaine penicillin (22,000 IU/kg IM every 12h or 44,000 IU kg IM q24h)

 ⇨ Inj. Oxytetracycline (10 mg/kg IV or IM every 24h)

 ⇨ Anthrax hyperimmune serum

PREVENTION & CONTROL

⇨ Report to authorities

⇨ Quarantine the area

⇨ Do not open carcass

⇨ Minimize contact

⇨ Wear protective clothing

➝ Latex gloves, face mask

⇨ Isolate sick animals

⇨ Discourage scavengers

⇨ Use insect control or repellants

⇨ Prophylactic antibiotics

⇨ Vaccination

➝In endemic areas

➝Endangered animals

Disinfection

➝ Spores of anthrax areresistant to heat, sunlight, drying and many disinfectants

Disinfectants

➝ Formaldehyde (5%)

➝ Glutaraldehyde (2%)

➝ Sodium hydroxide (NaOH) (10%)

➝ Bleach

Gas or heat sterilization

Gamma radiation

Preliminary disinfection

➝ 10% formaldehyde

➝ 4% glutaraldehyde (pH 8.0-8.5)

Cleaning

➝ Hot water, scrubbing, protective clothing

Final disinfection: one of the following

➝ 10% formaldehyde

➝ 4% glutaraldehyde (pH 8.0-8.5)

➝ 3% hydrogen peroxide,

➝ 1% peracetic acid

Preventing the introduction of infected animals to the unaffected areas.

The disease should be brought under the notice of regulating officials in case of an outbreak.

Care should be taken to destroy the dead body with deep burial and quicklime.

IMMUNIZATION

Anthrax vaccine should be administered annually 1-2 months prior to anthrax season.  

Vaccines used are as follow: 1.Pastuer vaccine 2.Spore vaccine 3.Sterne vaccine