Anthrax
- 1. Anthrax 17 November 2016 Alyssa, Sylvia, Alnino, Sara, Maggie
- 2. A history Sylvia Yakoo Fun fact: The name anthrax comes from the Greek word for coal and refers to the black lesions on the skin that it produces.
- 3. Microbiology ● Anthrax is caused by Bacillus anthracis is a Gram-positive bacteria ● Encapsulated ● Spore-forming ● Nonmotile rod ● Spores are the main infectious form ● Aerobic By Sara McElroy
- 4. Microbiology ● Spores are extremely small → they can travel all the way to the alveoli in the lungs ● Spores travel to the lymph nodes and mature into Anthrax bacteria ● Mature bacteria will release toxins
- 5. Microbiology B. anthracis has three main virulence factors: ● A poly-D-glutamic acid capsule (to protect it from phagocytosis) ● Three proteins that combine into two protein exotoxins ● Edema factor (EF) ● Lethal factor (LF) ● Protective antigen (PA) PA + EF Edema toxin PA + LF Lethal toxin
- 6. Epidemiology Incidence: ● U.S.: naturally-acquired anthrax is extremely rare (~ 1-2 cases of cutaneous disease per year). ○ Gastrointestinal anthrax is rare, but may occur as explosive outbreaks associated with ingestion of infected animals. ● Worldwide: unknown due to unreliable reporting, but is more common in: ○ agricultural regions of Central and South America, sub-Saharan Africa, central and southwestern Asia, southern and eastern Europe, the Caribbean. ○ developing countries ○ countries that do not have veterinary public health programs that routinely vaccinate animals By Alyssa Zlotnicki
- 7. Diagnosis ● Depends on: ○ Culture and isolation of B. anthracis ○ Detection of bacterial DNA, antigens, toxins ○ Detection of a host immune response to B.anthracis (serologic testing). ● Need to perform confirmatory testing, which includes one of: ○ isolate identification ○ antigen detection in tissues ○ quantitative serology ● Collect specimens for culture before antimicrobial therapy. ● Special Diagnostic procedures for inhalation anthrax: ○ thoracic imaging studies to detect a widened mediastinum or pleural effusion.
- 8. Two ways: ● Reflecting the route by which the disease was acquired ○ Cutaneous anthrax (95-99%), ■ acquired through skin lesion ■ case fatality with appropriate treatment: <1% ○ Ingestion (gastrointestinal, oral route) anthrax ■ contracted following ingestion of contaminated food, primarily meat from an animal that died of the disease. ■ case fatality: 25%-60% (estimation) ○ Inhalational (pulmonary) anthrax, from breathing in airborne anthrax spores. ■ case-fatality rates high even with appropriate antibiotics and supportive care (85% 20th century, 45% (5/11) post 2001) Transmission Classification
- 10. Occupation ○ nonindustrial anthrax ■ farmers, butchers, knackers/renderers, veterinarians, etc., ■ Usually cutaneous (infected carcasses) ■ parallels seasonal incidence in animals it is contracted from ■ insect bite transmission ■ alimentary canal infection (infected meat) ● industrial anthrax ■ people employed in the processing of bones, hides, wool, other animal products ■ usually cutaneous ■ inhalation anthrax much more likely to be industrial than non-industrial (result of dust being able to contain many spores)
- 11. Anthrax is seasonal and affects animals ● Sporadic outbreaks occur in grazing animals such as cattle or deer. ○ Sporulated forms shed by an animal dying or dead from anthrax generally provide the source of infection of other animals (ingestion, possibly inhalation anthrax) ● Tends to occur after hot, dry spells that follow heavy rains or flooding ● Modes of action: ○ Affects animal directly ■ influences way in which it makes contact with the spores ■ grazing closer to the soil in dry periods, forced to by lack of water ○ Affects animal indirectly ■ affects general health and level of resistance of animal to infection ■ affects ability of B. anthracis to germinate/sporulate. In the United States, yearly vaccination of livestock is recommended in areas where animals have had anthrax in the past.
- 12. Clinical Presentation of Signs and Symptoms ● 1 day-2 month incubation period ● Depends on infection type ○ All types cause severe illness/death if left untreated (pneumonia, blood infection) By Alnino Guarino
- 13. Cutaneous Anthrax (Most Common, Least Dangerous) ● Small blisters/bumps (may itch) ● Swelling around sore ● Painless skin sore (ulcer) on the face, neck, arms, hands
- 14. Inhalation Anthrax (Most Deadly) ● Fever/chills ● Chest discomfort ● Shortness of breath ● Cough ● Nausea, vomiting, stomach pains ● Fatigue/body aches
- 15. Injection Anthrax (Never Been Reported) ● Small blisters near injection site ● Painless skin sore w/ black center ● Swelling around sore ● Abscesses
- 16. GI Anthrax (Rare) ● Swelling of neck ● Sore throat ● Nausea/vomiting ● Diarrhea ● Stomach swelling/pain ● Flushing
- 17. Control ● Detection/Response to emergency (act of bioterrorism) ○ Samples to Laboratory Response Network (LRN) ○ Deployment of field staff ○ Mass shipment of medicine ○ Communication of life-saving information to the public ● Antibiotics (taken for 60 days) ○ Ciprofloxacin ○ Doxycycline ● Vaccines ○ Anthrax Vaccine Adsorbed (AVA) ○ Not available to public (can become publically available in an emergency) Also by Alnino Guarino
- 18. Discussion of Article Maggie Crawford
- 19. What Happened? Seven butchers participated in the slaughtering of sick cows & began to have skin swelling 3 days later - 2 butchers were eventually diagnosed w/ anthrax. Others borderline. All patients became stable The slaughtered cows had been taken to Jiangsu Province - Liaoning Province started having anthrax-infected cows popping up AND anthrax- infected people 35 cases of anthrax infection were reported from Aug-Sept 2012 - 7 in humans, 28 in cows Isolated a strain of anthrax from a dead cow and named it “Han”
- 20. What To Do? 1. Rule out that the vaccine strain is causing the outbreak - Injected Vac strain into mice and saw no death 2. Track the source of the anthrax outbreak 3. Rule out the possibility of a terrorist attack
- 21. How To Do It? Used genomic sequencing to look at similarities and differences between Han and Vac - SNP is less discriminatory, but adequate for phylogenetic reconstruction - MLVA can distinguish between closely related strains, less effective for molecular phylogeny → Different methods were used for different purposes (emergencies VS suspected bioterrorism)
- 22. What Did They Learn? SNP results: Han strain was markedly different from Vac strain MLVA results: Han clustered with previously reported Chinese strains - Han strain is naturally occurring isolate + NOT an engineered agent used for terrorism
- 23. Why Is This Important? - Set groundwork for future outbreak responses - Set groundwork for future epidemiology studies HOW?