The Plague is Back?


Well, actually the Plague never left. It's just now a disease that's been out there, causing occasionally and rarely a case in people, but continuing to infect animals. It's also a disease that we know how to prevent and treat.

The summer of 2015 has a seen a rise in this disease associated with fleas and rodents.  There have been 12 cases and 4 deaths. These cases have been all over the US: Arizona 2, California 1, Colorado 4, Georgia 1, New Mexico 2, Oregon 1, Utah 1.

In the summer of 2016, there has already been a case, in New Mexico.

Previous years have seen cases, but there were more in 2015.

It is the same disease that hundreds of years ago ravaged continents. The Justinian plague took 30-50 million people - about half the world's population - in the 6th century. 800 years later, the Black Death took 50 million lives over just a few years, from 1347 to 1351. 

It's found in places as far apart as Colorado and Madagascar.

The disease has been tamed by controlling fleas and rodents - and through the use of antibiotics.

The disease though has never entirely gone away. The plague remains in some wild rodent populations. The bacteria sometimes jumps to humans. Those with limited access to medical treatment are more at risk.

Around the world, 1000-2000 cases are reported to the WHO each year - with a few from the US each year. Of these, about 500 a year are from one country - Madagascar.

In the last few months of 2014, Madagascar has seen an increase in deaths - close to 50 deaths and over 100 reported cases - including in the capital city. A few cases each year are also identified in the US.

What is the Plague?

The Plague is a disease caused by the bacteria Yersinia pestis. 

It has two main forms.

  • Bubonic Plague is the most common form. It usually occur 2-6 days, or as late as 10 days after exposure (normally a bite from a flea). The disease begins with a sudden high fever, chills, and tender painful swollen lymph nodes (called Buboes, hence the name). The lymph nodes are usually in the groin but sometimes in the underarm or neck. If not treated with antibiotics, it can spread to other parts of the body.
  • Pneumonic Plague is when the bacteria spreads to the lungs when bubonic (or septicemic) plague is left untreated. It can also result from inhaling infectious respiratory droplets from someone with the pneumonic form. This infection would take only 1-3 days to develop. This type, if left untreated, can result in death in 24 hours. It is the only form that can spread person to person. It requires immediate antibiotic treatment. 2% of cases in Madagascar have been pneumonic.

There are other forms of the Plague:

  • Septicemic plague occurs when bacteria spreads throughout the blood, causing sepsis, shock, multi-organ involvement. Sometimes fingers, noses, and parts of skin turn black and are lost. It is less common and very dangerous. Without treatment, most infected die. Very high levels of bacteria are seen in the blood.
  • Plague Meningitis results in inflammation of the meninges which surround the brain and spinal cord due to the same bacteria.
  • Pharyngeal Plague is very uncommon. It looks like tonsillitis with a peritonsillar abscess and lymph nodes in the neck.

How is the Plague spread?

The bacteria is usually only found in wild rodents - prairie dogs, rats, mice, squirrels, and chipmunks. The bacteria jumps from one rodent to another by fleas. These infected fleas can spread the infection to other wild mammals (such as those that might be hunted) or to humans. Hunters can be infected by skinning an infected animal. Hunters and others can also be infected by their dogs who may carry infected fleas. Fleas can also jump person to person. Pneumonic Plague can create respiratory droplets that spread the disease by a cough or a breath from person to person. There is also a concern that it could be aerosolized for weaponization.

How is the Plague Treated?

Pneumonic, Septicemic, and Meningitic Plague need immediate antibiotics. Bubonic Plague also needs antibiotics but is not as immediately dangerous.

Those with very close contact to people sick with the pneumonic plague may be put under observation and may be given antibiotics (prophylaxis) to avoid developing the infection.

The disease can be fatal. Before antibiotics, it led to death in 66%. It often appears in places where medical treatment is harder to obtain and diagnoses may be delayed. As such, the WHO reports an 8-10% mortality rate. However, there are likely cases that result in death without diagnosis or official records.

What happened in Madagascar?

Plague infections and deaths are reported each year from Madagascar. There are 300 - 600 each year (80% of bubonic cases seen worldwide). These cases are usually seen between October and March. Most infections occur in rural areas, but sometimes within the capital, or even with in crowded jails in the capital that rats with fleas.

In the past in Madagascar, multi-drug resistant Plague has been found. The current cases have not been seen to be resistant, but it is always a worry.

Is the Plague found in the US?

It is found largely in the area of Northern New Mexico, northern Arizona, and southern Colorado, as well as in California, southern Oregon, and western Nevada.

An average of 7 cases a year are reported in the US. At least one case a year is found. In 1983, 40 cases were seen and in 2006, 17 cases were seen.

These cases are often associated with hunters skinning animals or with exposure to fleas from wild rodents.

The disease actually has been decimating Prairie Dog populations - and hurting the animals that rely on them, such as certain ferrets and plovers (birds).

The last urban Plague spread by rats in the US was in 1924-5 in Los Angeles

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