Bioterroism (Bacillus anthracis, Yersinia pestis, Smallpox, etc)

Define bioterroism

biological attack, the intentional release of viruses, bacteria, or other microorganisms that can sicken or kill people, livestock, or crops

What is the causative agent of anthrax?

Bacillus anthracis

List four reasons why agents of bioterrorism pose a risk to national security and health

1. Easily disseminated and transmitted
2. Result in high mortality rates and have the potential for major public health impact
3. Might cause public panic and social disruption
4. Require special action for public health preparedness

List examples of high-threat pathogens according to the CDC

Bacillus anthracis, Clostridium botulinum, Yersinia Pestis, Smallpox virus, Ebola (and other viral hemorrhagic fevers, Brucella)

What is the gram stain of Bacillus anthracis?

Large gram pos bacilli. Bamboo-stick appearance

What is a dangerous virulence factor for Bacillus anthracis?

Spores! It forms spores aerobically which is able to be inhaled easily

What animals are associated with Bacillus anthracis?

cattle, cowhides, goat hairs. It is an occupational hazard for those who handle livestock. Humans aquire the infection through direct contact with infected animal products, wool, or hair

Which form of Bacillus anthracis infection is the most common and least dangerous?

Cutaneous anthrax

How is Cutaneous anthrax obtained?

direct mucosal contact with infected animals, hides, or hairs

What is Cutaneous anthrax associated with? (job)

occupational hazards -- cattle ranchers, tannery workers

How does Cutaneous anthrax appear?

localized skin lesions

What is another name for Pulmonary anthrax?

Woolsorter's Disease

How does someone become infected with Pulmonary anthrax?

direct inhalation of spores

What is the mortality rate for Pulmonary anthrax?

80-90%

What is the incubation period for Pulmonary anthrax?

1-3 days VERY SHORT

How does Pulmonary anthrax start and how does it progress?

1. Spores attach to lymph nodes in lungs and germinate into bacterial cells within a macrophage
2. Pleural effusions cause infected macrophages to rupture, disseminating the organism into the bloodstream
3. From the bloodstream, the organism can spread all over the body

How can Bacillus anthracis become a bioweapon?

Anthrax spores can be produced in a lab and last a long time in the environment. Microscopic spores can be put into powders, sprays, food, and water

What are the Anthrax attacks of 2001?

Powdered anthrax spores were put into letters and then mailed through the US postal system. 22 people were infected.

What bacteria is the causative agent of the Bubonic Plague?

Yersinia pestis

What is the gram stain of Yersinia pestis?

gram neg bacilli that is non-motile and non-spore forming

Define zoonosis

infectious disease caused by a pathogen that has jumped from a non-human animal to human

What is the route of infection for Yersinia pestis?

Rodent to rodent -- or -- rodent to flea to human

How can humans become infected with Yersinia pestis?

through flea bite or handling infected animal/animal products

How does Yersinia pestis attack humans?

multiplies inside WBCs, lyses the cell, and spreads throughout the bloodstream and lymphatic system

What are some symptoms of Yersinia pestis infection?

swelling of cervical, axillary, and inguinal lymph nodes, hemtogenously spread to tissue and organs, disseminated intravascular coagulation, endotoxic shock, dark discoloration of extremities

How the plague diagnosed?

blood cultures and gram stains of lymph node aspirates, small gram neg coccobacilli

How will Yersinia pestis look like on blood smears?

May be intracellular (in a macrophage), or exhibit bipolar staining (safety pin appearance)

What is another name for smallpox?

variola virus

how is smallpox transmitted?

direct respiratory contact and multiplies in lymph nodes. This is followed by the viremic phase, with dissemination to various organs and the development of pox lesions

How is smallpox prevented?

vaccination

When was smallpox eradicated?

1980. All reference stocks of the virus were destroyed by the WHO in 1996. No one is vaccinated anymore in a smallpox free world.

What are the two known laboratories to have smallpox virus stock?

The Vector Institute in Russia and the CDC in the US. Because NKorea did not participate in the World Health Organization's smallpox eradication program, it is unknown whether they have any stock of the virus or not

Is Brucella species catalase pos or neg?

pos

Is Brucella species oxidase pos or neg?

pos

Can Brucella ferment sugars?

Non-fermenter, strictly aerobic

What is the gram stain of Brucella?

gram neg bacilli

Where is Brucella normally found?

Normal flora of the urinary and GI tracts of goats, pigs, cows, and dogs

What is the causative agent of brucellosis in animals and humans?

Brucella

How is Brucella become infective to humans?

ingestion of contaminated animal products (meat, milk, inhalation of aerosolized particles), direct contact through skin abrasions from handling infected animals

What animal has Brucella abortus?

cattle

What animal has Brucella melitensis and Brucella ovis?

Sheep and goats

What animal has Brucella suis?

pigs

What animal has Brucella canis?

dogs

What occupations are at an increased risk for contracting Brucella?

livestock handlers, slaughterhouse workers, farmers, veterinarians, laboratory personnel

What kind of fever can be caused by brucellosis?

undulant fever

What is undulant fever?

chronic and recurring fever that causes rising and falling fevers. occurs within one year or initial symptoms and includes undulant fevers, arthritis, chronic fatigue

What are the symptoms of acute undulant fever?

flu-like symptoms, fever, malaise, anorexia, weight loss, muscle and back pain

How can Brucella be identified?

can be isolated from bone marrow, CSF, wounds, but is most frequently isolated from blood

When are Brucella blood cultures most likely to become positive?

between 1st and 3rd week of infection

What can be used instead of a blood culture to confirm Brucella?

serum agglutination test (SAT), which is a serological test for antibodies in the patient serum. May be used to confirm infection

What makes Brucella a good bioterrorism candidate?

highly infectious through aerosolized route, making it an attractive pathogen for biological warfare

How can we stay safe from agents of bioterrorism in a laboratory setting?

Biosafety hoods must be used according to BSL level. Proper PPE must be used.