Important GramPositive Bacilli Three general groups 1 Endosporeformers

Important Gram-Positive Bacilli Three general groups: 1. Endospore-formers Bacillus, Clostridium 2. Non-endospore-formers Listeria, Erysipelothrix 3. Irregular shaped and staining properties Corynebacterium, Proprionibacterium, Mycobacterium, Actinomyces, Nocardia

Spore-forming Bacilli Genus Bacillus Genus Clostridium

Genus : Bacillus

General Characteristics of the Genus Bacillus n n n n Gram-positive, endospore-forming, motile rods Mostly saprobic Aerobic and catalase positive Versatile in degrading complex macromolecules Source of antibiotics Primary habitat is soil 2 species of medical importance: Bacillus anthracis n Bacillus cereus n

Anthrax Biological Terrorism ØMalignant Pustule ØMalignant Edema ØWool sorters disease ØSpleenic Fever

Characteristics n n n Bacillus anthracis Large, Gram positive, non-motile rod Vegetative form & spores Nearly worldwide distribution Over 1, 200 strains

Culture n Non-motile, spore-forming bacilli with square ends n “Medusa-head” colonies are like thick, wavy hairs under low power objective. Effect of CO 2 Dry leathery irregular colonies, close-up show wavy replicating rows of cells - Medusa head colonies

The Spore n Sporulation requires Poor nutrient conditions n Presence of oxygen n n Spores Very resistant to extremes n Survive for decades n Taken up by host and germinate n n Lethal dose 2, 500 to 55, 000 spores

Animal Transmission n Most commonly infected by ingestion from contaminated soil or contaminated feed or bone meal

Clinical Signs in Animals n Signs differ by species n n Ruminants at greatest risk Three forms of illness n Peracute n n Acute n n Ruminants (cattle, sheep, goats, antelope) Ruminants and equine Subacute-chronic n Swine, dogs, cats

n Peracute infection n Chronic infection Rapid onset n Pharyngeal and lingual edema n Sudden death n Ventral edema n Bloody discharge from body orifices n Death from asphyxiation n Incomplete rigor mortis n Treatment successful n Rapidly bloat n if started early

Anthrax : Four Types of Disease n Cutaneous n n n Septicemia n n n Most common form Seen in cattle, sheep and swine Peracute n n Dark, painless edematous lesion Seen in humans, swine, rabbits and horses Death within 1 -2 hours of onset of clinical signs Acute n Death within 24 hours of onset of clinical signs

Differential Diagnosis n Blackleg n Botulism n Poisoning n n n Plants, heavy metal, snake bite Lightening strike Peracute babesiosis

Anthrax Clinical Course n NEVER PERFORM A NECROPSY ON A SUSPECTED CASE OF ANTHRAX Ingestion of infected material and a 3 -day incubation period followed by: Peracute death or: n Varying degrees of: n High fever n Tachypnea n Tachycardia n Mucosal congestion n Neck and throat edema n ALL CASES END IN uncoagulated Dark, blood from all orifices, Delayed rigor mortis and splenomegaly

Diagnosis and Treatment n n n Necropsy not advised! Do not open carcass! Samples of peripheral blood needed n n Treatment n n Cover collection site with disinfectant soaked bandage to prevent leakage Penicillin, tetracyclines Reportable disease

Direct smear Mc. Fadyean’s reaction Pink coloration seen around cells

Anthrax: Control n Vaccination n Successful in endemic areas n Stern’s spore vaccine n Contains a strain of B. anthracis without a capsule (cured of p. XO 2 plasmid) n Organism is cleared rapidly from circulation n Protective antibodies are induced

What to do with infected carcasses • First call the state veterinarian for guidance • Bury DEEP (>6. 5 feet) with 6 inches of quick lime underneath and on top of carcass • Carcasses may also be burned (best)

Anthrax: Treatment n Effective treatment in the face of an outbreak includes: n Intravenous crystalline penicillin n Antiserum

Human Transmission n Industry Tanneries n Textile mills n Wool sorters n Bone processors n Slaughterhouses n

n Cutaneous Contact with infected tissues, wool, hide, soil n Biting flies n n Inhalational n n Tanning hides, processing wool or bone Gastrointestinal n Undercooked meat

Zoonotic Potential n Woolsorter’s Disease n n Fulminant respiratory infection Common in imported raw hide and wool (sorters) Ascoli’s precipitin test Malignant carbuncle n Cutaneous form of B. anthracis

Human Disease: Forms Cutaneous form: Skin form (Pathologists / Veterinarians)

Ingestional form or GI form (eating affected animals)

Inhalational or Pneumonic form Bioterrorism/ Wool Sorters Disease EM: Blood vessel with anthrax Lung Blood capillary plugged With Bacillus anthracis

Prevention and Control n n n Report to authorities Quarantine the area Do not open carcass Minimize contact Wear protective clothing n Latex gloves, face mask

Prevention and Control n n n Burn or bury carcasses, bedding, other materials Decontaminate soil Remove organic material and structures disinfect

Prevention and Control n n n Sick animals should be isolated Scavengers should be discouraged Insect control or repellants to prevent fly dispersal Prophylactic antibiotics Vaccination In endemic areas n Endangered animals n

Disinfection n n Effective disinfection can be difficult Prevention of sporulation best High pressure cleaners discouraged Soil 5% lye or quicklime n Hydrogen peroxide, peracetic acid, or gluteraldehyde n n Bleach 1: 10 dilution n May be corrosive

Disinfection n Preliminary disinfection n Cleaning n n 10% formaldehyde 4% glutaraldehyde (p. H 8. 0 -8. 5) Hot water, scrubbing, protective clothing Final disinfection: one of the following n n 10% formaldehyde 4% glutaraldehyde (p. H 8. 0 -8. 5) 3% hydrogen peroxide, 1% peracetic acid

Human Disease n Three forms Cutaneous n Inhalational n Gastrointestinal n

Cutaneous Anthrax n n n 95% of all cases globally Incubation: 2 -3 days (up to 12 days) Spores enter skin through open wound or abrasion Papule progresses to black eschar Severe edema Fever and malaise

Day 2 Day 4 Day 6

Day 4 Day 6

Cutaneous Anthrax n n n Case fatality rate 5 -20% Untreated – septicemia and death Edema can lead to death from asphyxiation Day 10

Cutaneous Anthrax n 2000 32 farms quarantined n 157 animals died n n 67 year old man in North Dakota Helped in disposal of 5 cows that died of anthrax n Developed cutaneous anthrax n Recovered with treatment n

Gastrointestinal Anthrax n Severe gastroenteritis n n n Incubation: 2 -5 days after consumption of undercooked, contaminated meat Case fatality rate: 25 -75% GI anthrax never documented in U. S. n Suspected cases in 2000

Inhalational Anthrax n n Incubation: 1 -7 days (highly variable) Initial phase n n Nonspecific - Mild fever, malaise Second phase Severe respiratory distress n Dyspnea, stridor, cyanosis, mediastinal widening, death in 24 -36 hours n n Case fatality: 75 -90% (untreated)

Diagnosis in Humans n Isolation of B. anthracis Blood, skin n Respiratory secretions n n Serology ELISA Nasal swabs n Screening tool

n Anthrax quick ELISA test New test approved by FDA on June 7 th, 2004. n Detects antibodies produced during infection with Bacillus anthracis n Quicker and easier to interpret than previous antibody testing methods n n Results in less than ONE hour

Treatment n Penicillin Has been the drug of choice n Some strains resistant to penicillin and doxycycline n n Ciprofloxacin Chosen as treatment of choice in 2001 n No strains known to be resistant n n Doxycycline may be preferable

Prevention and Control n − − • • • Humans protected by preventing disease in animals Veterinary supervision Trade restrictions Improved industry standards Safety practices in laboratories Post-exposure antibiotic prophylaxis

Vaccination n Cell-free filtrate Licensed in 1970 At risk Wool mill workers n Veterinarians n Lab workers n Livestock handlers n Military personnel n

Vaccine Side Effects n Injection site reactions Mild: 30% men, 60% women n Moderate: 1 -5% n Large local: 1% n n 5 -35% experience systemic effects n n Muscle or joint aches, headache, rash, chills, fever, nausea, loss of appetite, malaise No long-term side effects noted

Vaccine Schedule n n n 3 injections at two-week intervals 3 injections 6 months apart Annual booster

Protection Against Inhalational Anthrax 21 monkeys vaccinated at 0 and 2 weeks. o Challenged by anthrax spores at 8 No human week and 38 week later: All survived post o Challenged at 100 weeks: 88% exposure survived trials have n The two doses of vaccine (0 and 2 weeks) been documented provided protection for most animals for almost two years n