diease

Anthrax


OVERVIEW OF Anthrax :

It is an infectious disease caused by the bacterium Bacillus anthracis.The bacterium is found commonly in soil and commonly it affects the domestic and wild animals around the world.

Peoples tends to get the anthrax when they come in contact with the soil or contaminated animals.

The disease does not spread by human to human contact.

Animals come in to contact with the bacteria when they inhale them.Animals sucha as cattle.goats,antelope,deer are commonly affected with the anthrax bacilli.There are four types of anthrax:

Cutaneous

Inhalational

Gastrointestinal

Injection.


STRUCTURE of Anthrax :

It is an gram positive spore forming bacteria.

In culture the bacilli shows end to end and end of the bacilli shows truncated appearance,concave, and swollen and this gives the chain of bacilli a drum stick appearance.

It is capsid made of D glutamic acid which prevents the bacteria from phagocytosis mechanism by the host cell.

SPORE:

They show spore formation.they are formed in culture or soil which favours the growth of the bacteria.it is facilitated by nitrogen content in the soil,pH greater than 6,temperature greater than 15 degree,and presence of sodium chloride.

Duckering:A procedure used to reduce the spores in a wool below critical infection level.in thismethod 2% formaldehyde is used at 30-40◦c for 20 minutes and it results in disinfection of the wool.


EPIDEMIOLOGY :

Bacillus anthracis is used as an biological weapon(bioterrorism).


CAUSES :

It is mainly spread through animal and animal products

Inhaling the products contaminated with bacillus anthracis

Farmers and shepherds are at the higher risk for developing infection with this bacterium.


PATHOPHYSIOLOGY :

B.antracis is a non motile spore forming gram positive bacterium. The spores of B. anthracis, which can remain dormant in the environment for decades, are the infectious form, but vegetative B. anthracis rarely causes disease.spore introduced through the skin leads to cutaneous anthrax.those introduced through the GIT lead to gastrointestinal anthrax. and those introduced through the lungs lead to inhalation anthrax. After entering a human or animal, B. anthracis spores are believed to germinate locally or be transported by phagocytic cells to the lymphatics and regional lymph nodes, where they germinate. Tend to produce the Protective antigen (PA) and edema factor (EF) combine to form edema toxin (ET) and PA and lethal factor (LF) combine to form lethal toxin (LT). After binding to surface receptors, the PA portion of the complexes facilitates translocation of the toxins to the cytosol, in which EF and LF exert their toxic effects .


COMMON CLINICAL SIGNS AND SYMPTOMS :

Cutaneous anthrax:

This is the most common form of anthrax.The symptoms includes-

Small itchy or blisters on the skin surfaces

A painless swollen sore with a black center

Swelling in nearby lymph glands and tissues.

This is the mildest from and can be easily treated.

Gastrointestinal anthrax:

Abdominal pain and swelling

Diarrhoea

Loss of appetite

Flushing face and red eyes

Nausea and vomiting

Sore throat with difficulty in swallowing

Swelling of the neck and neck glands

Fever

Inhalational anthrax:

Initial symptoms

Chest discomfort

Coughing up of the blood

Nausea and vomiting,flu like symptoms

Progressive symptoms:

Low oxygen level

Meningitis and shock

This is the mostly deadly form of anthrax and it is fatal in 80-90% of the cases.

Injection anthrax:

It is more common among the people who inject heroin.

Initial symptoms:

Abscess in and around the injected site

Blisters and bumps,papules around the imjected site

Fever

A swollen sore is seen near the injected site.

Progressive form of the disease:

Memingitis

Organ failure

Shock


DIAGNOSTIC :

Skin testing:A sample of fluid from a doubtful lesions or a small tissue sample(biopsy) can be taken and lab sign may be investigated for cutaneous anthrax

Chest xray or computed tomography

Stool testing:it is used in gastrointestinal anthrax

Spinal tap(limbar puncture):The physician inserts the needle into your spunal canal and withdraws small amount of fluid.It is used in the investigation of meningitis caused by the bacterium.

Culture:

A.Nutrient agar:produce grayish and granular colonies.under lower power microscope it appears as long interlacing chain of bacilli resembling locks of matted air leading to medusa head appearance

B.Selective medium:Knisely’s polymyxin B lysozyme EDT thallous acetate (PLET) agar is an selective medium for isolation of bacillus anthracis.

C.Blood smear:Is isndone with polychrome methylene blue shows encapsulated bacilli(MC Faydean stain)

D.Gelatin Agar:In Gelatin agar it shows inverted fir tree appearance.


TREATMENT AND PROGNOSIS :

Haemodynamic support:

Fluids, vasopressor.blood products and haemodynamic support should be given to the patient suffering from anthrax since chances of sepsis is higher in this infection.Fresh frzen frozen plasma should be administeres in critical cases and fibrinogen levels should be maintained less than 100mg/dl. Because of the risk for coagulopathy, mechanical rather than pharmacologic prophylaxis is preferred for prevention of deep vein thrombosis.Risk of coagulaopathy,deep vein thrombosis and haemorrhage is common with this bacterium

Antimicrobial resistance:

Beta lactam antibiotics shows higher amount of resistance to the bacteriaHence they are contraindicated in the treatment plan.

Ciprofloxacin,Levofloxacin and doxycycline are the FDA approved drugs used in the treatment of the anthrax.

Meropenem a carbopenem group of drugs works well for meningitis caused by the anthrax bacterium.

Imipenem or cilastatin and doripenemcan be used for alternatives to the meropenem but chance sof seizures attack are more common among them.

To reduce the exotoxin production the protein inghibitors should be used.Linezolid is considered as the first line of treatment of protein synthesis inhibitor.But it is capable of penetrating into the CNS.If the patient si contraindicated to the Linezolid the alternative such as clindamycin can be administered.

Oral fluoroquinolones such as the ciprofloxacin,moxifloxacin,levofloxacin can be used as the first line of drugs in cutaneous anthrax.

Raximacumab,Oblitaxizumab and Anthrax Immune Globulin are the two anti toxin availableat present. Both antitoxins inhibit binding of PA to anthrax toxin receptors and translocation of the 2 primary toxins (LT and ET) into cells. They play a vital role in treating the systemic anthrax.

Anthim:A new drug approved by the FDA .It is an monoclonal antibody which is effective against the Anthrax bacteria.

Vaccination:

Anthrax vaccine adsorbed(AVA) is used in the emergency situations.It should be given at three doses first dose at the time of diagnosis and second and third dose at the intervals of 2 nd week and 4 week respectively.IT shows seroconversion after 3 doses of ADA.It is not an FDA approved drug and it is made available in the Emergency authorization department for the emergency purposes.


PROGNOSIS :

Inhalational anthrax has worst prognosi.chance of fatality is approximately 90%.

Other types of anthrax include 40-45% of the fatality rate


PREVENTION :

Eat the meats that has been properly slaughtered and cooked

Avoid raw contact with animals especially cattle,sheep goat


Medicines used in the Treatment :

Ciprofloxacin

Levofloxacin

Doxycycline

Raximacumab

Oblitaxizumab

Anthrax Immune Globulin


REFERENCE :

http://cdc.gov.net

http://mecinine.net

http://medicinenet.in

http://ncbi.net