History of Epidemics and Outbreaks
The disease is named ‘epidemic typhus’ due to the large-scale epidemics it caused in war zones and regions affected by natural disasters – the term is almost synonymous with the majority of wars throughout history. While the disease was well-described in 1498 during the Granada War. Scholars even suspect that it may have caused the Plague of Athens in 430 BC, a devastating epidemic that killed almost a quarter of the population !
It caused large-scale devastation during the Napoleonic Wars, in Ireland in the early 1800s, and during The Great Irish Famine in the late 1840s. Irish refugees fleeing the famine brought epidemic typhus over to the North American continent. Over 20,000 people, mostly Irish immigrants, in Canada died from the disease during the North American Typhus epidemic of 1847. The United States experienced its first epidemic in 1837 in the city of Philadelphia .
In the 20th century, epidemic louse-borne typhus was the biggest cause of death during World War I. Three million soldiers died in Russia and millions more in countries like Poland and Romania. By World War II, the development of an effective vaccine protected many soldiers. However, millions of prisoners in German Nazi concentration camps like Auschwitz, including Anne Frank, died from epidemic typhus due to the unhygienic conditions and a lack of vaccines , .
Nowadays, epidemic typhus cases are sporadic and found in the cooler mountainous regions of Asia, Africa, and South America. Burundi, Ethiopia, and Uganda have reported the largest number of cases since World War II .
The disease is also known by many other names, including epidemic typhus fever, camp fever, jail fever, gaol fever, war fever, red louse disease, ship fever, and more.
While rare, typhus has not been completely eradicated. Sporadic outbreaks continue to occur.
Who Discovered Epidemic Typhus?
Research work on epidemic typhus fever was fraught with the high risk of contracting the disease.
Charles-Jules-Henri Nicolle, a French physician, was the first to demonstrate that typhus could be transmitted from one person to another by body lice. In 1928, he was awarded the Nobel Prize in Physiology or Medicine for this discovery. During his work, he was infected with the disease and survived ,.
Many others who worked with R. prowazekii, however, succumbed to the infection. For example, Howard T. Ricketts, a researcher from the United States, became infected and died during his work on typhus in Mexico. In Europe, a Czech scientist called Stanislaus von Prowazek died from an epidemic typhus infection during research .
In 1916, Henrique da Rocha Lima, a Brazilian researcher who worked with Prowazek, continued the work on typhus and identified the bacteria as the pathogen causing epidemic typhus. He also introduced “Rickettsia” as a new class of microbes and named it after his colleagues Ricketts and Prowazek in honor of their work .
No story about typhus is complete without the accomplishments and fascinating story of Robert Weigl, a Polish zoologist. In 1920, Weigl created the first typhus vaccine. His success attracted the attention of many world leaders, including Adolf Hitler who allowed Weigl’s lab to flourish even as he invaded Poland. Weigl hired thousands of scientists, immunologists, mathematicians, and more to work in his lab and protect them from being sent to concentration camps or put to death. Weigl and his team smuggled the real vaccines into polish ghettos as part of the Polish resistance, and gallons of a weakened version to the Germans, saving the lives of many ,.
The development of the vaccine and the efforts of Robert Weigl, Hélène Sparrow, and numerous others helped drastically reduce the incidence and prevalence of epidemic typhus ,.
Pathogenicity and Life Cycle
The rickettsia family of bacteria is unique. They are obligate, intracellular, gram-negative coccobacillus parasites and constitute a separate group of bacteria. This is because they can be spread by fleas, ticks, body lice, and other such arthropods. Diseases caused by different varieties of Rickettsial bacteria are grouped together and known as Rickettsial diseases. These include typhus and spotted fever ,.
Body lice that are infected by the Rickettsia prowazekii bacteria are only vectors, not reservoirs. They turn red and die within five to six days of getting infected. At first, the bacteria multiply in the gut of the louse. The gut then detaches, ruptures, and releases the rickettsia bacteria into the feces ,.
A human can get infected if the infected feces come in contact with a bite site or a cut on the skin. It is important to note that the bite of an infected louse does not spread the disease to humans; the infected feces do. Humans may also inhale dried, infected lice feces through the air. Body lice that feed on the blood of a person infected with epidemic typhus can become infected, and the cycle continues .