Septicemic plague

The usual symptoms are:[1][2]

• Abdominal pain
• Bleeding under skin due to blood clotting problems
• Bleeding from mouth, nose or rectum
• Gastrointestinal symptoms, including nausea, vomiting, which can be with blood, and diarrhea
• Fever
• Chills
• Low blood pressure
• Organ failure
• Shock
• Death of tissue (gangrene) in extremities, mostly fingers, nose, and toes
• Difficulty breathing

These symptoms are common to many human illnesses, and are not considered, in and of themselves, to signify infection with any form of plague.

It is important to note that septicemic plague may be asymptomatic, and may cause death absent of any symptoms.

A doctor or veterinarian will perform a physical exam which includes asking about the medical history and possible sources of exposure.[4] The following possible test could include:

• Blood samples (detecting antibodies)
• Culture samples of body fluids (check for the bacteria Yersinia pestis)
• Kidney and liver testing
• Checking lymphatic system for signs of infection
• Examining body fluids for abnormal signs
• Checking for swelling
• Checking for signs of dehydration
• Checking for fever
• Checking for lung infection[5]

The following steps and precautions should be used to avoid infection of the septicemic plague:[1][5]

• Caregivers of infected patients should wear masks, gloves, goggles and gowns
• Take antibiotics if close contact with infected patient has occurred
• Use insecticides throughout house
• Avoid contact with dead rodents or sick cats
• Set traps if mice or rats are present around the house
• Do not allow family pets to roam in areas where plague is common
• Flea control and treatment for animals (especially rodents)

Starting antibiotics early is a first step in treating septicemic plague in humans. One of the following antibiotics may be used:

• Streptomycin
• Gentamicin
• Tetracycline or Doxycycline
• Chloramphenicol
• Ciprofloxacin

Lymph nodes may require draining and the patient will need close monitoring.[1]

In animals, antibiotics such as tetracycline or doxycycline can be used. Intravenous drip may be used to assist in dehydration scenarios. Flea treatment can also be used. In some cases euthanasia may be the best option for treatment and to prevent further spreading.[5]

Untreated septicemic plague is almost always fatal. Early treatment with antibiotics reduces the mortality rate to between 4 and 15 percent. Death is almost inevitable if treatment is delayed more than about 24 hours, and some people may even die on the same day they present with the disease.

In 2015, Taylor Gaes, a 16-year-old in Larimer County in northern Colorado, contracted septicemic plague and subsequently died after being bitten by a flea that had bitten a rodent on his family's rural property.[6] Only three people in Colorado had contracted the bacteria in the previous thirty years.[7]

Septicemic plague was the least common of the three plague varieties that occurred during the Black Death from 1348 to 1350[8] (the other two being bubonic plague and pneumonic plague). Like the others, septicemic plague spread from the East through trade routes on the Black Sea and down to the Mediterranean Sea.

Major port cities and trade centers such as Venice and Florence were hit the hardest. The massive loss of working population in Europe following the Black Death, resulting in increased economic bargaining power of the serf labour force, was a major precipitating factor for the Peasants' Revolt of 1381.

Septicemic plague is a zoonosis,[9] a disease that generally is acquired by humans from animals, such as rodents and carnivores. Goats, sheep and camels also may carry the bacteria. Cats rarely develop clinical signs but can be infected. Areas west of the Great Plains of North America are one region where plague-infected animals commonly occur. Plague-infested animals are found in many other countries as well, especially in developing countries where health controls are not effective.

Animals that commonly carry plague bacteria are largely rodents and Leporidae, but carnivores sometimes also become infected by their prey. Prey animals are not immune to the disease, and outbreaks of various strains of plague, such as sylvatic plague, have on occasion devastated populations of black-tailed prairie dogs and black-footed ferrets.[10]

Plague has been active in black-tailed prairie dog populations since the 1960s. In the United States outbreaks only occur in the western States and they are devastating, with mortality rates near 100% because the animals have no immunity to the plague. Survivors are the ones that happened not to become infected and colonies that recover from a plague outbreak remain at risk.[11]

Because black-footed ferrets prey on black-tailed prairie dogs, wild ferret populations also fall victim to sylvatic plague. An outbreak can kill nearly 100% of ferrets in a population, and surviving ferrets commonly face starvation because the prairie dogs are their main prey. Spray-and-vaccinate campaigns have aimed at preventing the spread of the plague among these animals.[12]

Similar septicemic problems occur in many countries across the world, especially in developing countries where spending on health systems is very low and health controls are not effective.