Rabies is one of the most well known zoonotic diseases in the world, and is transmissible between a wide range of animals from dogs, cats, bats, etc. and can infect any mammal.

Group: Group V ((−)ssRNA)
Order: Mononegavirales
Family: Rhabdoviridae
Genus: Lyssavirus
Species: Rabies lyssavirus

History:

Rabies was first recorded way back in the Mesopotamian Empire in 2000 B.C. In this culture, if an owner with a rabid dog did not take proper precautions against the dog biting others they would be fined. Rabies came to the new world in 1769 starting with a case in Boston. The majority of cases, 99%, are transferred between infected dogs and humans through bites, specifically the saliva. Rabies is considered one of the most concerning diseases of history and modem time. In 1885 a vaccine was developed in France by Louis Pasteur and Emile Roux for humans.

Facts about Rabies:

• One of the worst parts about rabies if its prevalence throughout the world and ability to rapidly disseminate.
• Rabies is present on all continents other than Antarctica
• Almost 99% fatal for human already showing symptoms or humans who are un-vaccinated
• Vaccination within 6 days of infections has been seen to have a 100% success rate for survival.
• In 2010, 26,000 people diseased from rabies within the world. This is a significant decrease from the 54,000 deaths in 1990.
• Well-known for its neurotropic effects- infecting nerve cells and altering human behaviors by shutting down the nervous system
• First signs and symptoms of the flu such as fever, headache and dizziness, but can progress to confusion, anxiety and agitation.
• Many people who are infected completely depersonalize in the later stages, reverting to pure “rage” personalities, attacking, biting scratching people and foaming at the mouth.
• Rabies infection is the main disease cited in sci-fi and fantasy for “zombie-like” behaviors and many story lines utilize signs and symptoms similar to rabies as zombie indicators. So… the zombie apocalypse is coming!
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Yersinia pestis is one of the most infamous microorganisms in the world- known commonly by the disease it causes: plague.

History of Yersinia pestis

The plague is first recorded during the Byzantine Empire during the reign of Justinian I, during 541 A.D. and continued to outbreak over the next 200 years, leaving over 25 million people dead (Rosen, 2007). Most commonly known for sweeping through the Old World during the Middle Ages and known as “The Black Death”, plague is on of the scariest infections in history. Starting in China during the 1300’s, this outbreak spread across trade routes and decimated an estimated 60% of all European populations (Benedictow, 2008). More recently, during the tail end of the 1800’s, plague was carried by ship routes throughout the world and had a 10 million mortality. The disease is carried by small animals such as rats, mice and squirrels, and jumps to humans through bites from fleas. The availability of small animal hosts quickly enables the transmission to a host of populations through carrier-mediated transmission.

Facts about Yersinia pestis and Plague

• There are three types of plague
  • Bubonic– characterized by sudden onset of fever headache, chills with tender lymph nodes. Results from the bite of a flea and localized to the nearest lymph nodes. If not treated, can spread to the rest of the body.
  • Septicemic– symptoms include fever, chills, abdominal pain, shock and bleeding into skin and organs. Skin and surrounding tissue may become necrotic (dead) and turn black. Transmissible from a flea bite or handling infected animals.
  • Pneumonic– symptoms include fever, chills, weakness and a rapid onset of pneumonia with secondary symptoms of chest pain, coughing and bloody mucous. Transmissible through inhaling infectious droplets, or from untreated bubonic or septicemic infections.
• Can be treated with modern day antibiotics
• Majority of modern day infections are confined to Sub-Saharan Africa or Madagascar, but cases have been seen in the United States (Arizona Included!), Europe, and India
• Plague vaccines were available, but were decommissioned. Currently, there are several different kinds of vaccines being developed but none available for use!
• Plague is considered to be one of the first uses of bioterrorism- many invading armies would catapult bodies infected with plague into cities to kill the opposition.
• Estimates of the plague say it has a mortality rate of 90-95%
• Some historians attribute social upsets to the plague such as the Fall of Rome, the beginnings of the Renaissance and lost of influence of the Catholic Church leading to Protestantism.

References

Benedictow, Ole J. 2004. The Black Death 1346-1353: The Complete History. Woodbridge: Boydell Press.

Centers for Disease Control and Prevention. 2015. Yersinia Pestis. National Center for Emerging and Zoonotic Infectious Diseases (NCEZID). Division of Vector-Borne Diseases (DVBD)

Khan, I. A. (2004). Plague: the dreadful visitation occupying the human mind for centuries. Transactions of the Royal Society of Tropical Medicine and Hygiene, 98(5), 270-277.

Rosen, William (2007), Justinian’s Flea: Plague, Empire, and the Birth of Europe. Viking Adult; pg 3; ISBN 978-0-670-03855-8.