THE BLACK PLAGUE

The Italian writer Boccaccio said the Plague’s victims often…

"ate lunch with their friends and dinner with their ancestors in paradise."

The Microscopic Killer Yersinia pestis

Discovered by Alexandre Yersin, a French bacteriologist in 1894.

LYMPH NODES The Black Plague attacks

the body’s “lymph nodes.” Lymph nodes are a part of

the immune system. They are sometimes called "glands,“

The purpose of lymph nodes is to protect the body from "foreign" invaders. These invaders may be bacteria, viruses, cancer, or other harmful substances.

LYMPH NODES continued… Y. pestis spreads through

the infected human until it reaches a lymph node, where it starts to bleed and swell,

The expansion of lymph nodes is the cause of the characteristic "bubo" (Bubonic) associated with the disease.

The Plague Life Cycle

Oriental Rat Flea

3 Forms of the Black Plague

1. BUBONIC

2. PNEUMIONIC

3. SEPTICEMIC

BUBONIC PLAGUE Fleas transmit the bacteria from animals

(eg, prairie dogs, squirrels, chipmunks, rats, cats) to humans.

Direct contact, animal bites or exposures to infected carcasses (eg, coyotes, hares, rabbits, rodents, marmots, goats) are other sources.

BUBONIC PLAGUE – images to follow

The onset of symptoms (after an incubation period of 4 to 7 days) is sudden and includes, high fever, headache, development of tender regional lymph nodes called buboes.

Untreated, bubonic plague can progress to septicemic and occasionally pneumonic plague in 2 to 6 days, and death is frequent.

The mortality rate of bubonic plague is low when treated early and is about 50% when untreated.

Cannot be transmitted from person to person.

BUBONIC PLAGUE IMAGES

PNEUMONIC PLAGUE Pneumonic plague is a severe bacterial lung

infection. Can take a primary or secondary form. The primary form is contracted from inhaling

droplets transmitted from an infected person. Secondary pneumonic plague is a progression of

bubonic or septicemic plague to the lungs.

PNEUMONIC PLAGUE – images to follow

Transmissible from human to human via droplets in air (cough, sneeze, etc.)

The mortality rate of pneumonic plague is 75 percent, despite appropriate plague treatment.

Pneumonic plague is classified as a Category A bioterrorism agent because of its ease of dissemination (spreading out), contagiousness, and high mortality rate.

PNEUMONIC PLAGUE IMAGES

SEPTICEMIC PLAGUE There are primary and secondary forms of

septicemic plague. The primary lacks the typical bubo. Secondary septicemic plague occurs when

there is the progression of bubonic to septicemic plague.

Rarely transmissible human to human.

SEPTICEMIC PLAGUE – images to follow

Septicemic plague causes fever, chills, weakness, abdominal pain, shock, and bleeding underneath the skin or other organs… regions such as the fingers, toes, and nose may become gangrenous, hence the term “black death.”

The mortality rate for septicemic plague is 50 to 90 percent if left untreated; 15% if diagnosed and treated early.

SEPTICEMIC PLAGUE IMAGES

Black Plague Doctor

Notice the extensive fabric,

Covered face, Crystal eyes, Beak-like mask

Does the Black Plague still exist today?

In the U.S., 1 to 40 cases reported annually (avg = 13 cases) by western states, 1971-1995

Worldwide, 2861 cases reported by 10 countries to WHO (World Health Organization) in 1995

Who is at risk? In the U.S., persons exposed to rodent fleas, wild

rodents, or other susceptible animals in areas of western states.

Most cases occur in southwestern states of NM, AZ, CO, and in CA

Highest rates in Native Americans, especially Navajos; other risk groups: hunters; veterinarians and pet owners handling infected cats; campers or hikers entering areas with outbreaks of animal plague

United States Distribution

Where in the world…?