1. Anthrax
Malignant Pustule, Malignant Edema, Woolsorters’ Disease, Ragpickers’ Disease, Maladi Charbon, Splenic Fever
Common names include: Malignant Pustule, Malignant Edema, Woolsorters’ Disease, Ragpickers’ Disease and Maladi Charbon. The word anthrax is derived from a Greek word meaning charcoal or carbuncle. Anthrax, the disease, likely originated 6,000-7,000 years ago in Mesopotamia and Egypt, where agricultural civilization was first recorded. Scientific literature first contained a reference to anthrax in 1769, by Fournier.

2. Overview Organism History Epidemiology Transmission Disease in Humans
Disease in Animals
Prevention and Control
In today’s presentation we will cover information regarding the organism that causes anthrax and its epidemiology. We will also talk about the history of the disease, how it is transmitted, species that it affects and clinical and necropsy signs observed. Finally, we will address prevention and control measures for anthrax.
Center for Food Security and Public Health Iowa State University

3. The Organism

4. The Organism Bacillus anthracis Large, gram positive non-motile rod
Vegetative form and spores
Nearly worldwide distribution
Over 1,200 strains
Bacillus anthracis is a gram positive rod µm wide by 3-5 µm long and can take two forms: the vegetative bacilli and the spore. Within the infected host the spores germinate to produce the vegetative forms which multiply, eventually killing the host. A proportion of the bacilli released by the dying or dead animal into the environment (usually soil under the carcass) sporulate, ready to be taken up by another animal. Although the vegetative forms of B. anthracis grow and multiply readily in normal laboratory nutrient agars or broths, they are more "fragile" than the vegetative forms of other Bacillus species, dying in simple environments such as water or milk. B. anthracis is more dependent on sporulation for species survival making it an obligate pathogen. Anthrax can be found nearly worldwide and has roughly 1,200 various strains. Top image: Bacillus anthracis non-hemolytic on sheep blood agar with “Medusa head” appearance (non-pigmented, dry ground glass surface, edge irregular with comma projections) Bottom image: B. anthracis bacilli Gram stain. Both images from CDC Public Health Image Library.
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5. The Spore Sporulation requires Spores
Poor nutrient conditions
Presence of oxygen
Spores
Very resistant to extremes
Survive for decades
Taken up by host and germinate
Lethal dose 2,500 to 55,000 spores
When conditions are not conducive to growth and multiplication of the vegetative bacilli, B. anthracis tends to form spores. Sporulation requires a nutrient poor environment and the presence of free oxygen. The spore form of anthrax is markedly resistant to biological extremes of heat, cold, pH, desiccation, and chemicals (and thus to disinfection). The spore form is the predominant phase in the environment, can survive for decades in soil, and it is through the uptake of spores that anthrax is contracted. Spores are not produced in the unopened carcass (within the anaerobic environment of an infected host the organism is in the vegetative form). It is estimated that 2,500 to 55,000 spores represent the lethal inhalation dose for humans. The image is an electron photomicrograph of a B. anthracis spore (arrowhead) partially surrounded by the pseudopod of a cultured macrophage (x137,000) from Dixon TC et al. Anthrax. N.Engl.J.Med. 1999;341:
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6. History

7. Sverdlovsk, Russia, 1979 94 people sick – 64 died
Soviets blamed contaminated meat
Denied link to biological weapons
1992
Soviet President Yeltsin admits outbreak related to military facility
Western scientists find victim clusters downwind from facility
Caused by faulty exhaust filter
This history section covers non-natural outbreaks or means of infection with anthrax. On April 2, 1979, there was an outbreak of anthrax in the Soviet city of Sverdlovsk (now called Ekaterinbrug) about 850 miles east of Moscow. Ninety-four people were affected, and at least 64 people died from inhalational anthrax. The Soviet government claimed that the outbreak was caused by intestinal anthrax from contaminated meat. The US believed that the Soviet Union was violating the Biological Weapons Convention signed in 1972 but the soviets denied any activities related to biological weapons. Thirteen years later, in 1992, President Boris Yeltsin admitted that the anthrax outbreak was the result of military activity at the facility. Western scientists were allowed to investigate in 1992 and found that all the victims were clustered along a straight line downwind from the military facility. Livestock in the same area also died of anthrax. The outbreak was caused by a faulty exhaust filter which was removed and not immediately replaced allowing aerosolized anthrax spores to escape the facility.
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8. South Africa,
Anthrax used by Rhodesian and South African apartheid forces
Thousands of cattle died
10,738 human cases
182 known deaths
Black Tribal lands only
White populations untouched
South Africa’s National Party and apartheid regime of the late 1970s sought to control revolutionary factions that advocated the overthrow of the government and the elimination of racial discrimination. The government used guerilla warfare and specially trained, secret groups that used biological and chemical weapons to fulfill their goals. These efforts included covert attacks throughout neighboring nations including Rhodesia (present day Zimbabwe) It is believed that within Rhodesia, from thousands of cattle died from intentionally introduced anthrax. 10,738 people contracted the disease, resulting in 182 deaths and a critical food shortage. Outbreaks were almost wholly limited to black inhabited Tribal Trust Lands. White populations remained untouched.
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9. Aum Shinrikyo Japanese religious cult 1993 Successful attempt in 1995
“Supreme truth”
1993
Unsuccessful attempts at biological terrorism
Released anthrax from office building
Vaccine strain used – not toxic
No human injuries
Successful attempt in 1995
Sarin gas release in Tokyo subway
1,000 injured – 12 deaths
In 1993, the Aum Shinrikyo, a Japanese religious cult meaning “supreme truth” made several unsuccessful attempts at biological terrorism through the release of anthrax in Tokyo. Anthrax was released from the cults Tokyo office building laboratory. Police and media reported foul smells, brown steam, some pet deaths and stains on cars and sidewalks. Fortunately, the strain of anthrax used in the attacks was the vaccine strain, lacking in essential toxic properties. As a result no human injuries were reported in any of these events. They were successful however, in 1995 when they released sarin gas in the subway system of Tokyo killing 12 and injuring over 1,000. Image: Aum Shinrikyo leader Shoko Asahara. Source: Chronology of Aum Shinrikyo's CBW activities, Center for Nonproliferation Studies, Monterey Institute of International Studies. Mangold,T.; Goldberg,J. Plague wars: The terrifying reality of biological warfare.
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10. 2001 Anthrax Letters
2001 saw the mailing of anthrax contaminated letters in the U.S. and the hysteria that followed. This terrorist attack showed how readily anthrax could spread and infect if manufactured in specific ways. Four recovered letters were sent to: Tom Brokaw at NBC, the New York Post, Senator Tom Dashle, and Senator Patrick Leahy. All were believed to have been mailed from Trenton, NJ. Images: CNN media postings.
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11. One thing that surprised public health officials was how the anthrax spores were able to escape sealed envelopes, contaminate postal machinery, and infect postal workers and mail recipients. A 94 year old woman died in Connecticut from anthrax. A letter sorted in New Jersey tested positive on the outside but not on the inside. Mail sorting machines were also found positive at the facility. It is speculated that the exposure source for this elderly woman was cross-contaminated mail. Images: CNN media postings.
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12. Anthrax Cases, 2001 22 cases 5 deaths (all inhalation) 11 cutaneous
Index case in Florida
2 postal workers in Maryland
Hospital supply worker in NYC
Elderly farm woman in Connecticut
There were a total of 22 cases of anthrax in the US in Eleven inhalation and 11 cutaneous with 5 deaths. The index case was a photojournalist in Florida; 2 postal workers in Maryland as well as a hospital supply worker in New York City. The last case was the elderly Connecticut farm woman.
Center for Food Security and Public Health Iowa State University

13. Anthrax Cases, 2001 7 month old boy Visited ABC Newsroom
Cutaneous lesion
Initial diagnosis:
spider bite
Punch biopsies confirmed anthrax
One of the cutaneous cases was a 7 month old boy who visited the ABC newsroom on September 28, The child had an elevated white blood count, was afebrile but had a 2-cm open sore, with surrounding erythema and induration, that oozed clear yellow fluid. There was swelling and erythema of the entire arm. The initial diagnosis was Loxosceles reclusa spider bite. After anthrax exposure was reported at another television network, two punch biopsies were taken. PCR and immunostaining for Bacillus anthracis were positive. Source: Roche K, Chang W., Lazarus H. Cutaneous Anthrax Infection. New England Journal of Medicine 2001;345:1611.
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14. Anthrax Cases, 2001 CDC survey of health officials following 9-11-01
7,000 reports regarding anthrax
4,800 phone follow-ups
1,050 led to lab testing
Less than 180 anthrax inquiries
During the time period September 11–October 17, 40 state and territorial health officials responded to a CDC telephone survey. An estimated 7,000 reports had been received at the health departments, approximately 4,800 required phone follow-up, and 1,050 reports led to testing of suspicious materials at a public health laboratory. In comparison, the number of anthrax threats reported to federal authorities during 1996–2000 did not exceed 180 reported threats per year.
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15. Anthrax Cases, 2001 Antimicrobial prophylaxis Ciprofloxacin
5,342 prescribed
60 day regime
44% compliance
57% suffered side effects
The antibiotic Ciprofloxacin was offered to many people in the aftermath of anthrax mailings in ,343 people were prescribed the medication for 60 days, 44% adhered to the 60 day treatment. Side effects were experienced by 3,032 people (57%) of those taking antibiotic prophylaxis and included diarrhea, abdominal pain, dizziness, nausea, and vomiting.
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16. Transmission

17. Human Transmission Industry Tanneries Textile mills Wool sorters
Bone processors
Slaughterhouses
Humans appear to be relatively resistant to anthrax. Anthrax in humans is generally acquired from animals by handling meat, hides, wool, hair, bones, etc. from infected animals. These routes can lead to inhalational or cutaneous anthrax. The best documented evidence of this comes from studies in the 1960’s in mills in which unvaccinated workers ‘chronically exposed’ to anthrax had annual case rates of %. In a study of two such mills, B. anthracis was recovered from the nose and pharynx of 14% of healthy workers; in another study, workers were inhaling spores during the working day with no ill effect, although a well-documented outbreak of pulmonary anthrax occurred in one mill with a similar level of contamination.
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18. Human Transmission Cutaneous Inhalational Gastrointestinal
Contact with infected tissues, wool, hide, soil
Biting flies
Inhalational
Tanning hides, processing wool or bone
Gastrointestinal
Undercooked meat
There are three main illnesses and routes of transmission in human anthrax. Cutaneous anthrax in humans can come from handling infected tissues, wool, hide, 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. Inhalation anthrax has been associated with tanning hides and processing of 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. Top image: wool hanging outdoors in Morocco. Bottom image: drum made of leather in Kenya sold as souvenirs.
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19. Animal Transmission
Most commonly infected by ingestion from contaminated soil or contaminated feed or bone meal
Animals shed the bacilli in terminal hemorrhages or spilled blood at death. Spores form when exposed to air and can contaminate the ground for many years. Skins and hides of infected animals may also be contaminated and harbor spores for years. Contaminated feed may also be a source of infection for livestock. Animal to animal transmission appears to be rare.
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20. Epidemiology

21. 20,000-100,000 cases estimated globally/year
Bacillus anthracis is found worldwide with an estimated 20, ,000 human cases each year (M. Swartz. Recognition and Management of Anthrax- An Update. Anonymous. New England Journal of Medicine. 345(22): , 2001). Anthrax remains common in various countries of Africa and Asia but, but is relatively rare in Europe, America, and Australiasia. Source:
20, ,000 cases estimated globally/year
Center for Food Security and Public Health Iowa State University

22. Anthrax in U.S. Cutaneous anthrax Inhalation anthrax
Early 1900’s: 200 cases annually
Late 1900’s: 6 cases annually
Inhalation anthrax
20th century: 18 cases/16 fatal
Cutaneous anthrax cases in the US early in the 20th century averaged 200 cases per year. During the second half of the century this decreased to approximately 6 cases per year. During the entire 20th century, there were 18 diagnosed cases of inhalation anthrax, 16 of which were fatal.
Center for Food Security and Public Health Iowa State University

23. Anthrax in the U.S. Outbreaks in soil endemic areas Alkaline soil
Wet spring that leads to grass kill followed by hot, dry period in summer or fall
“Anthrax weather”
Grass or vegetation damaged by flood-drought sequence
Outbreaks in the U.S. are most often associated with alkaline soil, and there are some areas where it is more endemic. Wet conditions followed by hot, dry weather in summer or fall are considered good conditions under which anthrax cases in livestock (cattle primarily) are likely to be seen. Vegetation may be damaged by this wet-dry cycle.
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24. Disease in Humans

25. Human Disease Three forms Cutaneous Inhalation Gastrointestinal
There are 3 forms of anthrax in humans: Cutaneous, gastrointestinal, and inhalation .
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26. Cutaneous Anthrax 95% of all cases globally
Incubation: 3-5 days (up to 12 days)
Spores enter skin through open wound or abrasion
Papule progresses to black eschar
Severe edema
Fever and malaise
The cutaneous form of anthrax accounts for 95% of all cases globally. Incubation is typically 3-5 days, but can be longer. Spores enter skin, typically via an abrasion or other open wound. A papule develops and progresses into a vesicle. The vesicle ruptures, becomes necrotic, and enlarges, forming an ulcer covered by a characteristic black eschar in 7-10 days. The eschar may be surrounded by moderate to severe non pitting, gelatinous edema. Low-grade fever and malaise are frequent. The eschar dries and tails off in one to two week.
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27. Day 2
This slide shows the progression of a cutaneous case. Head, forearms, and hands are most often affected. Images from CDC:
Day 4
Day 6
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28. Day 4
The pictures in the upper left show the eschars and edema of anthrax lesions. Lower right picture shows healing cutaneous anthrax lesion on the neck. Images from CDC:
Day 6
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29. Cutaneous Anthrax Case fatality rate 5-20%
Untreated – septicemia and death
Edema can lead to death from asphyxiation
The case fatality rate for cutaneous anthrax is 5-20%. If left untreated it can lead to septicemia and death. Death can occur through asphyxiation from the edema if the lesion is around the head or neck. Image from CDC:
Day 10
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30. Cutaneous Anthrax 2000 67 yr. old man in North Dakota
32 farms quarantined
157 animals died
67 yr. old man in North Dakota
Helped in disposal of 5 cows that died of anthrax
Developed cutaneous anthrax
Recovered with treatment
During the year 2000, 32 farms were quarantined for anthrax in the U.S. From July 6-Sept 24, 157 animals died. The last case of cutaneous anthrax reported before 2001, occurred in North Dakota in A 67 yr. old man, who helped dispose of 5 cows that had died of anthrax, developed cutaneous anthrax several days later. He was prescribed ciprofloxacin and recovered fully.
Center for Food Security and Public Health Iowa State University

31. Gastrointestinal Anthrax
Severe gastroenteritis
Incubation: 2-5 days after consumption of undercooked, contaminated meat
Case fatality rate: 25-75%
GI anthrax never documented in U.S.
Suspected cases in 2000
The symptoms of gastrointestinal anthrax appear typically two to five days, (up to 7 days) after the ingestion of undercooked meat containing anthrax spores. Severe gastroenteritis results consisting of nausea, vomiting, fever, and abdominal pain, progressing rapidly to severe, bloody diarrhea. The primary intestinal lesions are ulcerative and occur mainly in the terminal ileum or caecum. The case fatality rate is 25-75%. GI anthrax has never been documented in the United States, however there were suspect cases in Minnesota in 2000.
Center for Food Security and Public Health Iowa State University

32. Minnesota, 2000 Downer cow approved for slaughter by local vet
5 family members ate meat
2 developed GI signs
Diarrhea, abdominal pain, fever
4 more cattle die
B. anthracis isolated from farm but not from humans
Minnesota In late July 2000, a downer cow was approved for slaughter and consumption by the local veterinarian on a farm in Northern Minnesota. It was approved for family consumption. Five family members ate well cooked steak and hamburgers over the next few weeks and two reported gastrointestinal signs of diarrhea, abdominal pain and fever. When four more animals died, a carcass was tested and B. anthracis was isolated. While anthrax was never isolated from the human cases, they were placed on chemoprophylaxis and anthrax vaccine was initiated. Source: CDC. Human Ingestion of Bacillus anthracis-Contaminated Meat- Minnesota, August, Anonymous. MMWR 49(36): , 2000.
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33. Inhalation Anthrax Incubation: 1-7 days Initial phase Second phase
Nonspecific - Mild fever, malaise
Second phase
Severe respiratory distress
Dyspnea, stridor, cyanosis, mediastinal widening, death in hours
Case fatality: 75-90% (untreated)
The incubation period for inhalational anthrax is 1-7 days. There is some evidence to indicate that inhaled anthrax spores may take as long as 60 days to cause illness. In the initial phase it appears as a nonspecific illness characterized by mild fever, malaise, myalgia, nonproductive cough and some chest or abdominal pain. The illness progresses within 2-3 days leading to fever, dyspnea, cyanosis, stridor, mediastinal widening and subcutaneous edema of the chest and neck. The second stage is rapidly progressive health occurring within 24 to 36 hours. Case fatality rate is 75-95% if untreated. Best chance for survival is to receive antibiotics and medical care within the first 48 hours of onset of signs. Source: M. Swartz. Recognition and Management of Anthrax-An Update. New England Journal of Medicine 345(22): , 2001.
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34. X-ray evidence of mediastinal widening, and pleural effusion which are two common findings of inhalation anthrax. Source: J. Jernigan, D. Stephens, D. Ashford, C. Omenaca, M. Topiel, M. Gallbraith, M. Tapper, and et al. Bioterrorism-Related Inhalational Anthrax: The First 10 Cases Reported in the United States. Emerging Infectious Diseases 7: , 2001.
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35. Diagnosis in Humans Isolation of B. anthracis Serology ELISA
Blood, skin
Respiratory secretions
Serology
ELISA
Nasal swabs
Screening tool
Anthrax is diagnosed by isolating B. anthracis from the blood, skin lesions, or respiratory secretions or by measuring specific antibodies in the blood of persons with suspected cases. An ELISA was developed by the CDC for anthrax and was quickly qualified during the outbreak in the fall of It proved to be accurate, sensitive, reproducible and quantitative (see next slide for more details). The nasal swab test was used as a screening tool during the 2001 outbreak. Determining whether anyone else associated with the case-patient might have been exposed was important. In this setting, the nasal swab method was used for a rapid assessment of exposure, and as a tool for rapid environmental assessment. When the source of exposure is not known, nasal swabs can help investigators determine that information. They are not used for diagnosing anthrax and are not 100% effective in determining all who may have been exposed. Photo: Lung tissue from a fatal case showing Bacillus anthracis granular antigen staining inside a perihilar macrophage (red arrow) and intra- and extracellular bacilli (black arrow). (Immunohistochemical assay with a mouse monoclonal anti-B. anthracis cell-wall antibody and detection with alkaline phosphatase and naphthol fast red, original magnification 100X). Source: J. Jernigan, D. Stephens, D. Ashford, C. Omenaca, M. Topiel, M. Gallbraith, M. Tapper, and et al. Bioterrorism-Related Inhalational Anthrax: The First 10 Cases Reported in the United States. Emerging Infectious Diseases 2001;7:
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36. Diagnosis in Humans Anthrax quick ELISA test
New test approved by FDA on June 7th, 2004.
Detects antibodies produced during infection with Bacillus anthracis
Quicker and easier to interpret than previous antibody testing methods
Results in less than ONE hour
An ELISA test was approved by the FDA on June 7, 2004, in collaboration with the CDC. This ELISA test is quicker and easier to interpret than previous antibody testing methods and it can be completed in less than one hour, compared to about four hours for previous testing methods. Before the FDA approved of the test, very few laboratories other than the CDC and the U.S. Army had the ability to test blood for antibodies to anthrax. This ELISA test will be available shortly for use in state and private laboratories. Source: CDC Office of Communication. CDC Collaboration Yields New Test for Anthrax. CDC Media Relations June 7,
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37. Treatment Penicillin Ciprofloxacin Doxycycline may be preferable
Has been the drug of choice
Some strains resistant to penicillin and doxycycline
Ciprofloxacin
Chosen as treatment of choice in 2001
No strains known to be resistant
Doxycycline may be preferable
Penicillin has been the drug of choice for anthrax for many decades, and only very rarely has penicillin resistance been found in naturally occurring isolates. Preliminary data from the Florida, New York and Washington DC isolates showed possible resistance to penicillin so treatment with ciprofloxacin was recommended. Considerations for choosing an antimicrobial agent include effectiveness, resistance, side effects, and cost. No evidence demonstrates that ciprofloxacin is more or less effective than doxycycline for antimicrobial prophylaxis to B. anthracis. Widespread use of any antimicrobial will promote resistance. However, fluoroquinolone resistance is not yet common in these organisms. To preserve the effectiveness of fluoroquinolone against other infections, use of doxycycline for prevention of B. anthracis infection among populations at risk may be preferable.
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38. This chart describes some of the difference between inhalational anthrax and the flu or a cold. Main differences can be seen with lack of runny nose in inhalation anthrax and the lack of chest discomfort and/or vomiting in cases of cold or flu vs. inhalation anthrax. Source: MMWR. Considerations for Distinguishing Influenza-Like Illness from Inhalational Anthrax Vol 50, No 44; /09/2001
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39. Vaccination Cell-free filtrate Licensed in 1970 At risk
Wool mill workers
Veterinarians
Lab workers
Livestock handlers
Military personnel
The United States human anthrax vaccine is a cell-free filtrate, produced from an avirulent strain. The vaccine contains no whole bacteria, dead or alive. The vaccine was developed in the United States during the 1950s and 1960s for humans and was licensed by the FDA in Since 1970, it has been administered to at-risk wool mill workers, veterinarians, laboratory workers, livestock handlers and military personnel. The vaccine is manufactured by one company, the BioPort Corporation, formerly known as the Michigan Biologic Products Institute (MBPI).
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40. Vaccine Side Effects Injection site reactions
Mild: 30% men, 60% women
Moderate:1-5%
Large local:1%
5-35% experience systemic effects
Muscle or joint aches, headache, rash, chills, fever, nausea, loss of appetite, malaise
No long-term side effects noted
Vaccine side effects include injection site reactions. About 30% of men and 60% of women experience mild local reactions -- not unlike other vaccinations. 1-5% of individuals experience moderate local reactions. Large local reactions, occur at a rate of 1%. Beyond the injection site, from 5% up to 35% of people will notice muscle aches, joint aches, headaches, rash, chills, fever, nausea, loss of appetite, malaise, or related symptoms. Serious events, such as those requiring hospitalization, are rare and happen about once per 200,000 doses. There have been no patterns of long-term side effects from the vaccine, neither persistent nor delayed side effects.
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41. Vaccine Schedule 3 injections at two-week intervals
3 injections 6 months apart
Annual booster
The first three shots are given in two-week intervals. The following three shots are administered at 5 to 6 months after the previous dose. Annual boosters are given for prolonged protection. Source: Anthrax Vaccine Immunization Program.
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42. Protection Against Inhalational Anthrax
21 monkeys vaccinated at 0 and 2 weeks.
Challenged by anthrax spores at 8 week and 38 week later: All survived
Challenged at 100 weeks: 88% survived
The two doses of vaccine (0 and 2 weeks) provided protection for most animals for almost two years
No human post exposure trials have been documented
Anthrax vaccine efficacy has been demonstrated in a study in which it provided complete protection against aerosol challenge in monkeys at 8 weeks and 38 weeks, and 88 percent protection against similar challenge at 100 weeks. Annual boosters are necessary to maintain immunity. Source: Ivins BE, Fellows PF, Pitt MLM, et al. Efficacy of a standard human anthrax vaccine against Bacillus anthracis aerosol spore challenge in rhesus monkeys. Salisbury Medical Bulletin (September ) 1995;87(suppl):
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43. Vaccination
Only 152 people of more than 5,000 who were offered, took the vaccine post September 11th. During the Persian Gulf War in the early 1990’s approximately 150,000 Service Members (about 1 in 5 of the people who served in the operation) received at least one dose of anthrax vaccine.
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44. Animals and Anthrax

45. Clinical Signs in Animals
Signs differ by species
Ruminants at greatest risk
Three forms of illness
Peracute
Ruminants (cattle, sheep, goats, antelope)
Acute
Ruminants and equine
Subacute-chronic
Swine, dogs, cats
Copyright WHO
Clinical signs in animals differ by the species, with ruminants being the most at risk. The peracute form most often affects ruminants, including cattle, sheep and goats; the acute form will affect ruminants, as well as horses; and the subacute or chronic form most often affects swine, dogs, and cats. Antelope slide from WHO website.
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46. Ruminants Peracute infection Rapid onset Sudden death
Bloody discharge from body orifices
Incomplete rigor mortis
Rapidly bloat
In the peracute form of anthrax infection sudden death may be the only clinical sign, so careful attention should be paid to the carcass. The toxins in Bacillus anthracis prevent the blood from clotting so animals will often have bloody discharge coming from orifices, including the mouth, nostrils, eyes, ears, vulva, and anus. The carcass will decompose fairly rapidly leading to bloating, but rigor mortis will not be complete.
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47. Ruminants Acute infection: 1-3 days Fever, anorexia
Decreased rumination
Muscle tremors
Dyspnea
Abortions
Disorientation
Bleeding from orifices
Hemorrhages on internal organs
The course of an acute infection is usually 1-3 days but may take up to 7 days. An acute infection may manifest with a brief period of high fever (up to 107oF), excitement initially followed by depression, muscle tremors, staggering, dyspnea, cardiac distress, and disorientation prior to death. Cows may become anorexic with decreased ruminations, have lowered milk production that is often blood tinged or yellow, and suffer abortions. Subacute to chronic infections occur in less susceptible species such as pigs, but is also seen in cattle, horses, dogs and cats. The main symptoms are pharyngeal and lingual edema with animals dying from asphyxiation. Extensive localized subcutaneous edema of the ventrum, including the neck, sternum, and flank can also be seen. The carcass will decompose fairly rapidly leading to bloating, but rigor mortis will not be complete. Treatment with antibiotics can be successful if begun early in the course of the disease.
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48. Ruminants Chronic infection Treatment successful if started early
Pharyngeal and lingual edema
Ventral edema
Death from asphyxiation
Treatment successful if started early
Subacute to chronic infections occur in less susceptible species such as pigs, but is also seen in cattle, horses, dogs and cats. The main symptoms are pharyngeal and lingual edema with animals dying from asphyxiation. Extensive localized subcutaneous edema of the ventrum, including the neck, sternum, and flank can also be seen. The carcass will decompose fairly rapidly leading to bloating, but rigor mortis will not be complete. Treatment with antibiotics can be successful if begun early in the course of the disease.
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49. Differential Diagnosis
Blackleg
Botulism
Poisoning
Plants, heavy metal, snake bite
Lightening strike
Peracute babesiosis
Differential diagnosis for anthrax include other potential causes of acute death and include blackleg, botulism, poisoning (plants, heavy metals, snake bite) lightening strike and peracute babesiosis.
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50. Equine Ingestion Insect bite/vector
Enteritis, severe colic, high fever, weakness, death within hours
Insect bite/vector
Hot, painful swelling
Spreads to throat, sternum, abdomen, external genitalia
Death
Copyright WHO
Clinical signs in equine species, including horses, donkeys, mules, and zebras, are usually acute and vary depending on how they were exposed. Ingestion leads to enteritis, severe colic, anorexia, high fever, chills, bloody diarrhea, weakness, depression and death within hours. If a horse contracts anthrax via a bite from an insect, a localized hot, painful, subcutaneous swelling will occur. The swelling will soon spread to the throat causing dyspnea, sternum, abdomen, and external genitalia. This may last 1 to 3 days or even a week or longer prior to death. Do not open up the carcass if this is seen! Zebra photo from WHO website.
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51. Swine Sudden death without symptoms Localized swelling of throat
Death by asphyxiation
Ingestion of spores
Anorexia, vomiting, enteritis
Sudden death from anthrax can occur in swine without any symptoms. Localized swelling of the pharyngeal lymph nodes and lingual edema may cause death by asphyxiation. Ingestion of spores may cause anorexia, vomiting, enteritis, constipation, and sometimes bloody diarrhea. Swine are considered to be less susceptible to anthrax than other species, such as cattle, goats and sheep.
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52. Dogs & Cats Relatively resistant Clinical signs
Ingestion of contaminated raw meat
Clinical signs
Fever, anorexia, weakness
Necrosis and edema of upper GI tract
Lymphadenopathy and edema of head and neck
Death
Due to asphyxiation, toxemia, septicemia
Anthrax infection is generally rare in dogs and cats but can occur when they ingest contaminated carcasses or animal by-products. Ingested organisms can cause local irritation and inflammation of the oropharynx and throat or pass to the intestines and cause a bacteremia and gastroenteritis. Spread to the local and mesenteric lymph nodes, spleen, and liver usually occurs. Subsequent swelling of the head and neck tissues can occur leading to asphyxiation. Chronic infection can spread to the local and mesenteric lymph nodes, spleen, and liver. Dogs and cats will then show signs of fever, depression, anorexia, weakness, prostration and death. Carnivores and omnivoires are generally more resistant to anthrax and recovery is common.
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53. Diagnosis and Treatment
Necropsy not advised!
Do not open carcass!
Samples of peripheral blood needed
Cover collection site with disinfectant soaked bandage to prevent leakage
Treatment
Penicillin, tetracyclines
Reportable disease
Necropsy of affected carcasses is not advised, because aerobic spores are released into the environment and bodily fluids will contaminate the area. Due to poor clotting, a blood sample can be taken post mortem from a superficial vessel, such as the jugular vein. This is the safest and most effective way of making a diagnosis. Blood smears should be made and the blood submitted for isolation of B. anthracis. The collection site should be covered with a disinfectant-soaked bandage to prevent leakage of contaminated blood. The organism is very sensitive to penicillin and tetracyclines, and these are the antibiotics of choice if the infection is detected early. Care must be taken in handling infected tissues or carcasses, because the organism can penetrate cuts in the skin, resulting in localized infection with subsequent dissemination. Anthrax is a notifiable disease.
Center for Food Security and Public Health Iowa State University

54. Dogs/Pigs Inhalational Anthrax
Experimental studies
14 dogs and 14 pigs infected
8/14 pigs had transient fevers
3/14 dogs significant temp elevations
B. anthracis
Isolated from lungs and pulmonary lymph nodes of dogs
Never isolated from blood
An experimental study was conducted on dogs and pig where they were exposed to aerosolized anthrax. Animals were killed on days 3-13 and day 30 for pathology examination. Pulmonary lesions were seen in the 3 animals killed on days 8,10, and 11. B. anthracis was never isolated from blood, but was isolated from lungs and pulmonary lymph nodes of dogs. Gleiser CA, et al. J. comp path 1968:78.
Center for Food Security and Public Health Iowa State University

55. Case-Report Mississippi, 1991
Golden retriever, 6 yrs old
2 days ptyalism and swelling of RF leg
Temp 106°F, elevated WBC
Died same day
Necropsy
Splenomegaly, friable liver, blood in stomach
2x2 cm raised hemorrhagic leg wound
Some pulmonary congestion
In 1991 in Mississippi a 6 year old golden retriever presented with a history of 2 days ptyalism and swelling of right front leg, elevated temp (106°F) and elevated white blood count (25,900/μl). The dog died the same day. Necropsy showed: splenomegaly, friable liver, blood in the stomach and intestines, a 2x2 cm raised hemorrhagic wound on RF leg, some pulmonary congestion, with bacteria in hepatic sinusoids, renal glomerular capillaries, and myocardial blood vessels. Death attributed to toxemia/septicemia. Anthrax was confirmed with electron microscopy.
Center for Food Security and Public Health Iowa State University

56. Case-Report Mississippi, 1991
Source of exposure in question
Residential area
1 mile from livestock
No livestock deaths in area
Dove hunt on freshly plowed field days prior to onset
Signs consistent with ingestion but cutaneous exposure not ruled out
The circumstances of this case leave several unanswered questions regarding the source of exposure of this dog to anthrax. Exposure was considered unlikely during the 6 days prior to death because the dog was kept at home, albeit unrestrained, in a residential area with no livestock within approximately 0.8 km. No livestock deaths had been reported at this site. Exposure to the dog was presumed to have occurred 6 days prior to initial clinical signs (7 days prior to death) during a dove hunt over a freshly plowed field. One possible source includes carrion ingested in adjacent wooded areas, although a carcass was not found. Ingestion would be the most likely explanation for the gastrointestinal hemorrhage found at necropsy. A second possibility is percutaneous infection, such as a wound or an insect bite. Although cutaneous anthrax has not been described in animals, wound contamination could not be ruled out.
Center for Food Security and Public Health Iowa State University

57. Animal Anthrax Vaccine
Recommended for livestock in endemic areas
Sterne strain
Live encapsulated spore vaccine
Immunity in 7-10 days
Other countries use in pets and exotics
No safety or efficacy data
Adjuvant may cause reactions
Working dogs may be at risk
Annual vaccination of livestock in endemic areas is recommended. The most widely used vaccine is the Sterne-strain vaccine. It is a non-encapsulated live variant strain of B. anthracis developed in Immunity develops 7-10 days after vaccination. The vaccine produced in the US is licensed for use in livestock only (cattle, sheep, horses, goats and swine) No US anthrax vaccine is licensed for use in pets. In other countries live spore vaccines produced from the Sterne strain have been used to vaccinate pets and exotic species. No safety or efficacy data is available. The vaccine contains saponin as an adjuvant and its use in cats and dogs may produce injection site reactions. Data are not sufficient to provide recommendations to vaccinate cats and dogs for anthrax. Cases in domestic cats are very rare. Working dogs might put themselves at risk by exposure to dead carcasses. Dogs respond well to antibiotic treatment. Search and rescue dogs might be considered for vaccination.
Center for Food Security and Public Health Iowa State University

58. Animal Disease Summary
Anthrax should always be high on differential list when
High mortality rate in group of herbivores
Sudden death with unclotted blood from orifices
Localized edema
Especially neck of pigs or dogs
Anthrax should always be high on a different list when there is high mortality in a group of herbivores. When sudden death occurs with unclotted blood from orifices and where localized edema occurs, especially of the neck in pigs and dogs.
Center for Food Security and Public Health Iowa State University

59. Prevention and Control

60. Prevention and Control
Report to authorities
Quarantine the area
Do not open carcass
Minimize contact
Wear protective clothing
Latex gloves, face mask
Vaccination of susceptible animals
Anthrax is a notifiable disease, if anthrax is suspected the state veterinarian and local health officials should be contacted. Do not open the carcass to perform a necropsy due to the potential for contamination and exposure. Make sure there is minimal contact with the carcass by establishing a quarantine area, generally for 21 days after the last anthrax death. Wear protective clothing, such as a face mask and gloves, if it is necessary to work with the dead animal. Be sure to cover any areas of broken skin on yourself so that no infectious organisms come in contact with those areas. The animal anthrax vaccine can be used on susceptible healthy livestock if authorities feel it is necessary. Photo of a veterinarian in Mali preparing to vaccinate cattle for anthrax.
Center for Food Security and Public Health Iowa State University

61. Prevention and Control
Burn or bury carcasses, bedding, other materials
Decontaminate soil
Remove organic material and disinfect structures
Since necropsies are not advised, it is best to burn or bury the carcasses and all contaminated materials. Then decontaminate the soil with 5% lye or quicklime (anhydrous calcium oxide). If animals have contaminated structures, remove the organic material and disinfect with an approved chemical.
Center for Food Security and Public Health Iowa State University

62. Disinfection Effective disinfection can be difficult
Prevention of sporulation best
High pressure cleaners discouraged
Soil
5% lye or quicklime
Hydrogen peroxide, peracetic acid or gluteraldehyde
Bleach 1:10 dilution
May be corrosive
Effective disinfection of spores can be extremely difficult and, under some circumstances, it may not be possible to achieve this completely. It is important, therefore, to act promptly following cases of anthrax in order to prevent, as far as possible, the release and sporulation of vegetative cells from the dying or dead animal. High pressure cleaners are discouraged because of the greater potential to spread the contamination through aerosols. Decontaminate soil with 5% lye or quicklime (anhydrous calcium oxide), hydrogen peroxide, peracetic acid or gluteraldehyde may be good alternatives. Commercially available bleach or 0.5% hypochlorite solution (a 1:10 dilution of household bleach may be used but it may be corrosive to some surfaces.
Center for Food Security and Public Health Iowa State University

63. Disinfection Preliminary disinfection Cleaning
10% formaldehyde
4% glutaraldehyde (pH )
Cleaning
Hot water, scrubbing, protective clothing
Final disinfection: one of the following
3% hydrogen peroxide,
1% peracetic acid
Where practical, cleaning of all surfaces should be done by straightforward washing and scrubbing using ample hot water. Protective clothing should be worn. For final disinfection, one of the following disinfectants should be applied at a rate of 0.4 liters per square metre for an exposure time of at least 2 hours:· 10% formaldehyde (approximately 30% formalin); 4% glutaraldehyde (pH ); 3% hydrogen peroxide; 1% peracetic acid. Hydrogen peroxide and peracetic acid are not appropriate if blood is present. When using glutaraldehyde, hydrogen peroxide or peracetic acid, the surface should be treated twice with an interval of at least one hour between applications. Formaldehyde and glutaraldehyde should not be used at temperatures below 10 oC. After the final disinfection, closed spaces such as rooms or animal houses should be well ventilated before use. The effectiveness of the disinfection procedure cannot be assumed and attempts should be made to confirm it has been adequate by means of swabs and culture.
Center for Food Security and Public Health Iowa State University

64. Biological Terrorism: Estimated Effects
50 kg of spores
Urban area of 5 million
250,000 cases of anthrax
100,000 deaths
100 kg of spores
Upwind of Wash D.C.
130,000 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 the release of anthrax 10 km upwind and 2 km wide will extend for approximately 20 km over 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 U.S. Congressional Office of Technology Assessment estimated 130,000 to 3 million deaths following the aerosolized release of 100 kg of anthrax spores upwind of Washington D.C.
Center for Food Security and Public Health Iowa State University

65. Acknowledgments
Development of this presentation was funded by a grant from the Centers for Disease Control and Prevention to the Center for Food Security and Public Health at Iowa State University.
Center for Food Security and Public Health Iowa State University

66. Acknowledgments Author: Co-authors: Radford Davis, DVM, MPH
Jamie Snow, DVM, MPH
Katie Steneroden, DVM, MPH
Center for Food Security and Public Health Iowa State University