What is Plague?
Plague can affect people in three main ways.- Bubonic plague initially affects the lymph nodes, usually in the groin area. Gangrene so affected individuals that the loss of extremities like fingers, toes, and the nose provoked the expression “black death" in medieval times.
- Septicaemic plague infects the entire body through the bloodstream.
- Secondary pneumonic plague involves the lungs. This last kind of plague, while not common, is especially dangerous because it can be passed from person to person easily through respiratory droplets, the kind coughed and sneezed out and spread like with the flu virus.
All kinds of plagues are caused by the same bacteria, Yersinia pestis. Bubonic plague and septicaemic plague can spread to the lungs resulting in secondary pneumonic plague. Approximately 30 to 60 percent of people untreated for plague will die.
Plague Transmission
Plague is transmitted by fleas infected with Yersinia pestis bacteria. The bacteria is picked up from rats and other animals, especially rodents like ground squirrels, but also rabbits, hares, carnivorous wild animals and domestic cats. Fleas, and especially the oriental rat flea, Xenopsylla cheopsis, are the main carrier of plague in most of the world, although the human flea, Pulex irritans, is the usual culprit of plague transmission in the Andean region of South America.About.com's Guide to Weather describes the role of the weather in unleashing a plague epidemic in AD 541 that killed half of the population of the Roman empire.
Plague in the World
Plague is found almost anywhere there is interaction between wild rodents and domestic rats. The western part of the United States, most of South America, most of Africa except West Africa, central and Southeast Asia, and southeastern Europe bordering the Caspian Sea are the main plague hot spots. Natural plague may also occur in other parts of the world such as Russia and Kazakhstan. Although plague is found in many countries, today more than 98% of human plague cases and deaths are found in Africa.About.com's Guide to Medieval History has a great series on the history of the plague and its impact on the world before the time of antibiotics. The Centers for Disease Control in the United States has a great plague page with more information about plague than you'll probably ever want.
Plague and Cats
If you have a pet cat, just keep your cat free of fleas to reduce the chances your cat could spread plague. Keep in mind that from 1977 to 1994 there were only 17 cases of primary plague pneumonia spread by pet cats.Plague and Bioterrorism
Plague is a potential bioterrorism weapon as it can be manufactured quite easily and the methods to spread it through the air already exist. Plague bacteria could theoretically be spread with an aerosol causing people to get pneumatic plague that could spread to other people. If many people suddenly come down with plague symptoms, an alert should be made for both plague and anthrax.Plague Symptoms
About 3 to 7 days after a flea bite, the following flu-like symptoms may appear. Beware: These symptoms could easily be caused by a number of other diseases. Symptoms vary depending on the kind of plague. Bubonic plague victims typically have a swollen lymph node that may open up to drain called a bubo, but people with septacaemia or pneumonic plague may not have a bubo at all.- Fever
- Chills
- Feeling ill
- Numbness is some parts of the body
- Nausea
- Sore throat
- Headache
Diagnosis
Initial diagnosis of plague may be based on the identification, under a microscope, of plague bacteria in fluid aspirated from swollen lymph nodes, sputnum, or cerebro-spinal fluid, CSF. Positive identification of plague bacteria in those samples should be further confirmed with FA or ELISA. Plague bacteria cultured from aspirated buboes, blood, CSF and/or sputnum or a four times or greater increase in antibody titer tests confirm the diagnosis of plague. A test called PHA, passive hemagglutinin test, is frequently used to determine plague in the blood. A rapid dipstick test is available for use when laboratory support is not available, but laboratory diagnosis should follow this quick check. Your physician should be aware of areas that are endemic for plague in considering a diagnosis. Likewise, doctors should know if the patient has been visiting other regions or countries.Plague Treatment
Almost everyone suffering from plague survives if treated as soon as possible, so rapid diagnosis is very important. Patients are treated with antibiotics and supportive therapy as necessary. Streptomycin is the drug of choice, or gentamicin where streptomycin is unavailable. Tetracyclines and chloramphenicol are treatment alternatives. Chloramphenicol may also be used to treat plague meningitis. Other drugs that may be used to treat plague are doxycycline and trimethoprim-sulfamethoxazole. Buboes, the infected lymph nodes, may need to be drained.Plague and Travel Restrictions
For travelers disembarking from a plague infected ship or aircraft, the first action taken will be disinsection; that’s right, getting rid of insects. The aim is to eliminate fleas that may be crawling around the body or in the clothes and luggage. Afterwards the travelers may be monitored for 6 days until it is clear that they are not infected with plague.For people coming from an area with pneumonic plague, they must be isolated for six days before embarking on an international trip.
A patient is considered infectious if they have pneumonic plague and will be isolated until completing 48 hours of the proper antibiotic treatment. Even if the patient shows signs of getting better, the doctor may wish to keep the patient in an isolation ward for about a week or longer.
Just for Fun: The Origin of Boo boo
After a quick search on the Internet, I saw I was not alone in thinking that the term bubo could have been the origins of the term boo boo. The endearing term for little cuts and scrapes on children may have its origins in the sores arising from bubonic plague, buboes.