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Archive for August 2nd, 2009

Pneumonic Plague Strikes Chinese Town

Posted by feww on August 2, 2009

For Updates See Comments Section

Chinese town quarantined after plague kills 1, infects 11 others

Up to ten thousand people have been placed under quarantine in the town of Ziketan in Qinghai province in northwest China after a 32-year-old herdsman died of pneumonic plague and 11 others were confirmed infected with the deadly infection, AP reported the Chinese health authorities as saying.

ziketan china
Location Map, Ziketan, Qinghai province, China. Image source: Google Maps. Image may be subject to copyright.

According to the Associated Press

The 32-year-old herdsman died in Ziketan in Qinghai province, the provincial health bureau said in a statement posted on its Web site Saturday. It didn’t say when he died. Most of the others infected are relatives of the deceased and are in stable condition in a hospital, the bureau said. The town of 10,000 people has been placed under quarantine and a team of experts has been sent to the area, it said.

An emergency Health Bulletin issued by the Qinghai health bureau has warned all visitors to Ziketan and neighbouring areas since July 16 who may have developed a fever or a cough to seek medical treatment.

What’s Plague?

Plague is an infectious disease caused by bacteria called Yersinia pestis. The bacteria are found mainly in rodents, particularly rats, and in the fleas that feed on them. Other animals and humans usually contract the bacteria from rodent or flea bites, the US National Institute of Health (NIH) said. The bacteria can also spread from person to person through the air by coughing. When transmission occurs through the air, Y. pestis infects the lungs. [See below for the disease forms.]

Historically, plague destroyed entire civilizations. In the 1300s, the “Black Death,” as it was called, killed approximately one-third (20 to 30 million) of Europe’s population. In the mid-1800s, it killed 12 million people in China. Today, thanks to better living conditions, antibiotics, and improved sanitation, current World Health Organization statistics show there were only 2,118 cases in 2003 worldwide.

About 20 people in the United States are diagnosed with bubonic plague each year caused by flea or rodent bites—mostly from infected prairie dogs—in countryside in the southwestern United States, according to NIH.  “About 1 in 7 of those infected die from the disease. There has not been a case of person-to-person infection in the United States since 1924.”

There have also been small plague outbreaks in Asia, Africa, and South America.

What’s Pneumonic Plague?

Yersinia pestis
Image: Yersinia pestis. Fluorescence antibody positivity is seen as bright, intense green staining around the bacterial cell. [Source: CDC]

Facts about Pneumonic Plague [Information Sourced from CDC]

PHIL_2050_lores
Image: Wayson stain of Yersinia pestis. Wayson stain of Yersinia pestis. Note the characteristic “safety pin” appearance of the bacteria
. [Source: CDC]

Plague is an infectious disease that affects animals and humans. It is caused by the bacterium Yersinia pestis. This bacterium is found in rodents and their fleas and occurs in many areas of the world, including the United States.

Y. pestis is easily destroyed by sunlight and drying. Even so, when released into air, the bacterium will survive for up to one hour, although this could vary depending on conditions.

PHIL_4091_lores
This patient presented with symptoms of plague that included gangrene of the right hand causing necrosis of the fingers. In this case, the presence of systemically disseminated plague bacteria Y. pestis, i.e. septicemia, predisposed this patient to abnormal coagulation within the blood vessels of his fingers.
Photo: CDC 1975. Caption: CDC/ CDC/Dr. Jack Poland

Pneumonic plague is one of several forms of plague. Depending on circumstances, these forms may occur separately or in combination:

  • Pneumonic plague occurs when Y. pestis infects the lungs. This type of plague can spread from person to person through the air. Transmission can take place if someone breathes in aerosolized bacteria, which could happen in a bioterrorist attack. Pneumonic plague is also spread by breathing in Y. pestis suspended in respiratory droplets from a person (or animal) with pneumonic plague. Becoming infected in this way usually requires direct and close contact with the ill person or animal. Pneumonic plague may also occur if a person with bubonic or septicemic plague is untreated and the bacteria spread to the lungs.
  • Bubonic plague is the most common form of plague. This occurs when an infected flea bites a person or when materials contaminated with Y. pestis enter through a break in a person’s skin. Patients develop swollen, tender lymph glands (called buboes) and fever, headache, chills, and weakness. Bubonic plague does not spread from person to person.
  • Septicemic plague occurs when plague bacteria multiply in the blood. It can be a complication of pneumonic or bubonic plague or it can occur by itself. When it occurs alone, it is caused in the same ways as bubonic plague; however, buboes do not develop. Patients have fever, chills, prostration, abdominal pain, shock, and bleeding into skin and other organs. Septicemic plague does not spread from person to person.

Symptoms and Treatment

PHIL_4139_loresThis patient presented with symptoms of plague that included gangrene of the right foot causing necrosis of the toes. In this case, the presence of systemically disseminated plague bacteria Y. pestis, i.e. septicemia, predisposed this patient to abnormal coagulation within the blood vessels of his toes. Photo CDC. Caption: CDC/William Archibald

With pneumonic plague, the first signs of illness are fever, headache, weakness, and rapidly developing pneumonia with shortness of breath, chest pain, cough, and sometimes bloody or watery sputum. The pneumonia progresses for 2 to 4 days and may cause respiratory failure and shock. Without early treatment, patients may die.

Early treatment of pneumonic plague is essential. To reduce the chance of death, antibiotics must be given within 24 hours of first symptoms. Streptomycin, gentamicin, the tetracyclines, and chloramphenicol are all effective against pneumonic plague.

Antibiotic treatment for 7 days will protect people who have had direct, close contact with infected patients. Wearing a close-fitting surgical mask also protects against infection.

A plague vaccine is not currently available for use in the United States.

Plague Information: Infection Control

6581_lores
During the 1975 Rhodesian, (now Zimbabwe), Marburg epidemiologic investigation, health officials came across this African farmer with an inguinal bubo. Photo: CDC 1975. Caption: CDC/ Dr. J. Lyle Conrad

The epidemiologists uncovered an outbreak of plague amongst the local farmers, and treated these patients with oral antibiotics. Sanitarians were quickly dispatched to spray huts for fleas, and then trap rats carrying the pathogenic agent, Yersinia pestis bacterium.

PHIL_4140_lores
This patient acquired a plague infection through abrasions on his upper right leg. Bubonic plague is transmitted through the bite of an infected flea, or as in this case, exposure to inoculated material through a break in the skin. Symptoms include swollen, tender lymph glands known as buboes. Photo: CDC 1975. Caption: CDC/ CDC/Dr. Jack Poland

6720_lores
This photograph depicts the shaved anterior thoracoabdominal region of a rock squirrel, Spermophilus variegatus, formerly known as Citellus variegatus, which is afflicted with the plague. This squirrel is displaying a petechial rash, which is similar in appearance to those found on humans also afflicted with Yersinia pestis. A petechial rash refers to small, pinpoint, flat lesions of the skin and mucous membranes that are associated with hemorrhages beneath the skin surface. Photo: CDC 1977. Caption: CDC/ William Archibald; Laboratory/ Ft. Collins

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