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Anthraxis anacutedisease caused by the bacteriumBacillus anthracis. Most forms of the disease are lethal, and it affects both humans and animals. There are now effective vaccines against anthrax, and some forms of the disease respond well to antibiotic treatment.
Cutaneous Anthrax:An acute illness, or post-mortem examination revealing a painless skin lesion developing over 2 to 6 days from a papular through a vesicular stage into a depressed black eschar with surrounding edema. Fever, malaise and lymphadenopathy may accompany the lesion.Inhalation Anthrax:An acute illness, or post-mortem examination revealing a prodrome resembling a viral respiratory illness, followed by hypoxia, dyspnea or acute respiratory distress with resulting cyanosis and shock. Radiological evidence of mediastinal widening or pleural effusion is common.Gastrointestinal Anthrax:An acute illness, or post-mortem examination revealing severe abdominal pain and tenderness, nausea, vomiting, hematemesis, bloody diarrhea, anorexia, fever, abdominal swelling and septicemia.Meningeal Anthrax:An acute illness, or post-mortem examination revealing fever, convulsions, coma, or meningeal signs. Signs of another form will likely be evident as this syndrome is usually secondary to the above syndromes.Definition Contd..
Originates from Greek for black or coal because of black eschar (characteristic of cutaneous form of anthrax) It is principally disease of herbivorous e.g. cattle, goat, sheep, cow but it has the potential to affect other mammals also.Human infection results from direct and indirect exposure to infected animals or occupational exposure to infected or contaminated animal products/ Also known as Wool Sorter`s Disease or Malignant pustuleUsed as a weapon of Bioterrorism.
Anthrax Global Distribution
20,000 to 100,000 cases estimated globally/yearhttp://www.vetmed.lsu.edu/whocc/mp_world.htm
Bacillus anthracis - Gram positive non-motile, spore forming rod with a diameter of 1.5 m and length of 5 m , found in soil, herbs, vegetation, etc.
Spores can remain viable for decades so used as bio-weapon. They are also resistant to heat, UV ray, radiation and most disinfectants.
Spores are the predominant form in the environment.
It is through the uptake of spores that anthrax is contracted.
It is a Zoonosis.Human infection occur as a result of contact with the infected animal or animal products e.g.- goat hair in textile mills, animal skin and contaminated articles.Modes: Inoculation of spores in breaks of skin, Inhalation of spores, Ingestion of contaminated food mainly meat.Human to Human Transmission are extremely rare.
CutaneousContact with infected tissues, wool, hide, soilBiting fliesInhalationalTanning hides, processing wool or boneDirect inhalation of spores from contaminated articles (used for bioterrorism)GastrointestinalUndercooked meat specially
*There are three main routes of anthrax transmission in humans. Cutaneous anthrax may occur when handling infected tissues, wool, hides, soil, and products made from contaminated hides or hair, such as drums, rugs, or brushes. Biting flies are also suspected of being mechanical vectors of anthrax to humans under certain conditions. Inhalational anthrax has been associated with tanning hides and processing wool or bone. Gastrointestinal anthrax occurs when individuals eat undercooked contaminated meat from animals that have died of anthrax. Laboratory acquired cases have also occurred.
[The top image shows wool hanging outdoors. Bottom image: Cattle hides. Source (for both): pixabay.com-public domain]
TanneriesTextile millsWool sortersBone processorsSlaughterhousesLaboratory workersBio weapon
*People with occupational exposure to animal products are at risk of anthrax infection. This includes workers in tanneries, textile mills, wool sorters, and others. In the 1960s, unvaccinated mill workers were chronically exposed to anthrax; case rates of 0.6 to 1.4% were observed. B. anthracis was recovered from the nose and pharynx of 14% of healthy workers in one study; in another study, workers were inhaled 600 to 1300 spores during the working day with no ill effect. A well-documented outbreak of pulmonary anthrax occurred in one mill with a similar level of contamination.
[Photo shows two men shearing sheep. Source: geograph.org.uk-creative-commons]
Bacteria present in hemorrhagic exudates from mouth, nose, anusInhalation:
Spores formSoil contaminationSporulation does not occur in a closed carcassSpores viable for decades
In infected animals, large numbers of bacteria are present in hemorrhagic exudates from the mouth, nose, and anus. When they are exposed to oxygen, these bacteria form spores and contaminate the soil. Sporulation also occurs if a carcass is opened and oxygen exposure occurs sporulation does not occur inside a closed carcass. Anthrax spores can remain viable for decades in the soil or animal products, such as dried or processed hides and wool. Spores can survive for two years in water, 10 years in milk, and up to 71 years on silk threads. Vegetative organisms are thought to be destroyed within a few days during the decomposition of unopened carcasses.*
Most commonHerbivoresContaminated soilHeavy rainfall, droughtCarnivoresContaminated meatInhalationMechanical (insects)
*In animals, transmission occurs by ingestion and possibly inhalation of spores, although entry through skin lesions has not been ruled out. Herbivores usually become infected when they ingest sufficient numbers of spores in soil or on plants in pastures. Outbreaks are often associated with heavy rainfall, flooding, or drought. Contaminated bone meal and other feed can also spread this disease. Carnivores usually become infected after eating contaminated meat. Vultures and flies may disseminate anthrax mechanically after feeding on infected carcasses.
[This photo shows cattle grazing in a pasture. Source: U.S. Department of Agriculture, NRCS]
Mainly three types :-
1. Cutaneous Anthrax
2. Pulmonary Anthrax
3. Gastro intestinal Anthrax
Commonest form : over 95% of all casesIncubation period : 2 -6 daysPapule, Vesicle, Ulcer followed by coaled black necrotic EscherLesion painless & non purulentResolution of eschar occurs over 6 weeks and is not hastened by treatmentSelf limiting over 90% resolve without complication.
Occur due to inhalation of spores from contaminated animal hides and products.Common among workers exposed occupationally to high concentration of viable sporesIncubation period 1 day to 8 weeks.Clinical Presentation Malaise, Fever, Cough, Nausea, drenching sweats, shortness of breath,
In severe form rapidly developed hypotension,cyanosis and death.CFR Case fatality rate in unintervention is 100%.Survival was reported when antibiotic was given in prodromal period & multidrug regimen used.
Following ingestion of organism in contaminated foodIncubation Period : 2 to 5 daysTwo clinical forms - Intestinal anthrax and Oropharyngeal anthraxIntestinal :- nausea, vomiting, fever, abdominal pain, diarrhoea, haemetemesis, ascites , may be fatal.Oropharyngeal sore throat, dysphagia, fever, lymphadenopathy in neck etc
Anthrax Meningitis :
- it is haemorrhagic also.- may develope in 30-40% cases. - 100% Mortality.
Anthrax and Biological Warfare Countries > 10 countries in the worldClouds of spores of Anthrax bacilli aerosol ( war heads filled with anthrax spores) - Through dried spores in envelopsSeptember 9/11 WTC attackPostal workers affected Inhalation anthraxUS Columbia, Florida, New Jersey, N. YorkOther parts of the world
22 cases (11 inhalation, 11 cutaneous) in 4 states and DCB. anthracis sent through U.S. mailMost exposures occurred in mail sorting facilities and sites where mail was opened
50 kg of spores
Urban area of 5 millionEstimated impact250,000 cases of anthrax100,000 deaths100 kg of spores
Upwind of Washington D.C.Estimated impact130,000 to 3 million deaths
*Previous acts of biological terrorism have been small in scale. It is estimated that in a city of 5 million people, a release of 50 kg of anthrax spores (10 km upwind and 2 km wide) would extend over 20 km in 2 hours. This would result in 500,000 people placed at risk. There would be an estimated 250,000 illness and 125,000 deaths. A 1993 report by the U.S. Congressional Office of Technology Assessment estimated that 130,000 to 3 million deaths may occur following the aerosolized release of 100 kg of anthrax spores upwind of Washington D.C.
Do not open suspicious mail
inappropriate or unusual labelingstrange or no return addresspostmark different from return addressexcessive packaging materialKeep mail away from faceNo not blow or sniff mail or mail contentsWash hands after handlingAvoid vigorous handling (tearing, shredding)Discard envelopes
Clinical and History of exposure.Bacteriology Gram Stain & CultureSerology ELISA for anthrax antibodies, - Detection indicates past infection or vaccination while a four fold rise in titers indicate recent infection.PCR
SPECIMEN TO COLLECT ( HUMAN ANTHRAX)
Cutaneous anthrax: Vesicular exudate swabs and capillary tube aspirate
Intestinal anthrax: - Stool sample - isolate guinea pig inoculation - Blood( venipuncture) smear examination for bacilli - Peritoneal fluid for culture - Paired sera for Ab
Pulmonary anthrax: If mild disease ( No sample) Severely ill Blood , sputum,