Epidemic typhus

Did You Know?

• Brill–Zinsser disease is a mild form of epidemic typhus that recurs after a long period of latency, often in times of immunosuppression.
• Symptoms include fever, chills, headache, confusion, cough, rapid breathing, body aches, rash, nausea, and vomiting.
• Complications can include myocarditis, endocarditis, pneumonia, meningitis, encephalitis, and septic shock.

Transmission

The disease starts when a louse bites a person infected with Rickettsia prowazekii. Inside the louse, the bacteria multiply in its gut and pass out with its droppings. When that louse later bites someone else, the bite itches. The person scratches, and the infected feces get ground into the scratch. It takes one to two weeks for symptoms to show. The bacteria can stay alive and dangerous in dried louse feces for days. Typhus eventually kills the louse, but the bacteria survive for weeks inside the dead insect. Outbreaks have flared up in wartime and poverty, like in Nazi concentration camps during World War II, where poor sanitation in places such as Auschwitz, Theresienstadt, and Bergen-Belsen let typhus spread. In the 2000s, refugee camps after famines or natural disasters pose similar risks. Between outbreaks, flying squirrels act as a natural reservoir for the bacteria. In 1916, Henrique da Rocha Lima proved that Rickettsia prowazekii causes typhus. He named it after Stanislaus von Prowazek, who died from the disease while researching it, and H. T. Ricketts, another scientist who died from typhus. In 1930, Rudolf Weigl made a vaccine by grinding up infected lice that had fed on blood, but making it was dangerous. A safer vaccine, grown in egg yolks, was created by Herald R. Cox in 1938 and became widely used by 1943.

Treatment

The infection is treated with antibiotics such as tetracycline, chloramphenicol, and doxycycline. Intravenous fluids and oxygen may be needed to stabilize the patient. Untreated mortality ranges from 10 to 60 percent, while treatment with antibiotics within 8 days of initial infection reduces mortality to close to zero. Prevention focuses on avoiding louse infestation: completely changing clothing, washing infested clothing in hot water, and treating bedsheets. Clothes left unworn and unwashed for 7 days kill lice and their eggs. Dusting clothing with powders containing 10% DDT, 1% malathion, or 1% permethrin also kills lice and their eggs. Individuals should avoid unhygienic, extremely overcrowded areas and keep distance from larger rodents such as rats, squirrels, or opossums.

History

Epidemic typhus is one of the leading theories for what caused the Plague of Athens during the Peloponnesian War, a disease that took the lives of Pericles and his two oldest sons in 430 BC. The illness struck Athens again in 429 BC and in the winter of 427/6 BC. The earliest known written account of typhus may date to 1083 at La Cava abbey near Salerno, Italy. In 1546, the Florentine doctor Girolamo Fracastoro included a description of typhus in his work on contagion, De Contagione et Contagiosis Morbis. Soldiers returning from Cyprus brought typhus to mainland Europe. The first dependable record of the disease comes from the 1489 siege of the Emirate of Granada, where accounts note fever, red spots on the arms, back, and chest, followed by delirium, gangrenous sores, and the smell of rotting flesh. During that siege, 3,000 Catholic soldiers died in combat, but 17,000 more perished from typhus. In crowded, unsanitary prisons, where lice thrived, typhus was called Gaol fever. The Black Assize of Oxford in 1577 saw over 510 deaths from epidemic typhus, including Speaker Robert Bell. The outbreak that followed from 1577 to 1579 killed roughly one in ten people in England. At the Lent assize in Taunton in 1730, typhus killed the Lord Chief Baron of the Exchequer, the High Sheriff of Somerset, the sergeant, and hundreds more. By 1759, an English official estimated that a quarter of all prisoners died from gaol fever each year.

Society and culture

Typhus was one of more than a dozen agents the United States researched as potential biological weapons before President Richard Nixon suspended non-defensive aspects of the program in 1969. The CDC lists the Andean regions of South America and parts of Africa as active foci of human epidemic typhus, and recognizes an active enzootic cycle in the United States involving flying squirrels. Serological examination of homeless persons in Houston found evidence of exposure to the bacterial pathogens causing epidemic typhus and murine typhus. A study of 930 homeless people in Marseille, France, found high rates of seroprevalence to Rickettsia prowazekii and a high prevalence of louse-borne infections. Typhus has been increasingly discovered in homeless populations in developed nations, as these populations migrate and often cannot maintain necessary hygienic standards. The prevalence of typhus is affected by weather, humidity, poverty, and lack of hygiene, with lice and typhus more prevalent during colder months when people wear multiple layers of clothing.