Epidemic typhus


Epidemic typhus, also known as louse-borne typhus, is a form of typhus so named because the disease often causes epidemics following wars and natural disasters where civil life is disrupted. Epidemic typhus is spread to people through contact with infected body lice, in contrast to endemic typhus which is usually transmitted by fleas.
Though typhus has been responsible for millions of deaths throughout history, it is still considered a rare disease that occurs mainly in populations that suffer unhygienic extreme overcrowding. Typhus is most rare in industrialized countries. It occurs primarily in the colder, mountainous regions of central and east Africa, as well as Central and South America. The causative organism is Rickettsia prowazekii, transmitted by the human body louse. Untreated typhus cases have a fatality rate of approximately 40%.
Epidemic typhus should not be confused with murine typhus, which is more endemic to the United States, particularly Southern California and Texas. This form of typhus has similar symptoms but is caused by Rickettsia typhi, is less deadly, and has different vectors for transmission.

Signs and symptoms

Symptoms of this disease typically begin within 2 weeks of contact with the causative organism. Signs/symptoms may include:
  • Fever
  • Chills
  • Headache
  • Confusion
  • Cough
  • Rapid breathing
  • Body/muscle aches
  • Rash
  • Nausea
  • Vomiting
After 5–6 days, a macular skin eruption develops: first on the upper trunk and spreading to the rest of the body.
Brill–Zinsser disease, first described by Nathan Brill in 1913 at Mount Sinai Hospital in New York City, is a mild form of epidemic typhus that recurs in someone after a long period of latency. This recurrence often arises in times of relative immunosuppression, which is often in the context of a person suffering malnutrition or other illnesses. In combination with poor sanitation and hygiene in times of social chaos and upheaval, which enable a greater density of lice, this reactivation is why typhus generates epidemics in such conditions.

Complications

Complications are as follows:
Feeding on a human who carries the bacterium infects the louse. R. prowazekii grows in the louse's gut and is excreted in its feces. The louse transmits the disease by biting an uninfected human, who scratches the louse bite and rubs the feces into the wound. The incubation period is one to two weeks. R. prowazekii can remain viable and virulent in the dried louse feces for many days. Typhus will eventually kill the louse, though the disease will remain viable for many weeks in the dead louse.
Epidemic typhus has historically occurred during times of war and deprivation. For example, typhus killed millions of prisoners in German Nazi concentration camps during World War II. The unhygenic conditions in camps such as Auschwitz, Theresienstadt, and Bergen-Belsen allowed diseases such as typhus to flourish. Situations in the twenty-first century with potential for a typhus epidemic would include refugee camps during a major famine or natural disaster. In the periods between outbreaks, when human to human transmission occurs less often, the flying squirrel serves as a zoonotic reservoir for the Rickettsia prowazekii bacterium.
In 1916, Henrique da Rocha Lima proved that the bacterium Rickettsia prowazekii was the agent responsible for typhus. He named it after his colleague Stanislaus von Prowazek, who had along with himself become infected with typhus while investigating an outbreak, subsequently dying, and H. T. Ricketts, another zoologist who had died from typhus while investigating it. Once these crucial facts were recognized, Rudolf Weigl in 1930 was able to fashion a practical and effective vaccine production method. He ground up the insides of infected lice that had been drinking blood. It was, however, very dangerous to produce, and carried a high likelihood of infection to those who were working on it.
A safer mass-production-ready method using egg yolks was developed by Herald R. Cox in 1938. This vaccine was widely available and used extensively by 1943.

Diagnosis

IFA, ELISA or PCR positive after 10 days.

Treatment

The infection is treated with antibiotics. Intravenous fluids and oxygen may be needed to stabilize the patient. There is a significant disparity between the untreated mortality and treated mortality rates: 10-60% untreated versus close to 0% treated with antibiotics within 8 days of initial infection. Tetracycline, chloramphenicol, and doxycycline are commonly used.
Some of the simplest methods of prevention and treatment focus on preventing infestation of body lice. Completely changing the clothing, washing the infested clothing in hot water, and in some cases also treating recently used bedsheets all help to prevent typhus by removing potentially infected lice. Clothes left unworn and unwashed for 7 days also result in the death of both lice and their eggs, as they have no access to a human host. Another form of lice prevention requires dusting infested clothing with a powder consisting of 10% DDT, 1% malathion, or 1% permethrin, which kill lice and their eggs.
Other preventive measures for individuals are to avoid unhygienic, extremely overcrowded areas where the causative organisms can jump from person to person. In addition, they are warned to keep a distance from larger rodents that carry lice, such as rats, squirrels, or opossums.

History

History of outbreaks

Before 19th century

During the second year of the Peloponnesian War, the city-state of Athens in ancient Greece had an epidemic, known as the Plague of Athens, which killed, among others, Pericles and his two elder sons. The plague returned twice more, in 429 BC and in the winter of 427/6 BC. Epidemic typhus is proposed as a strong candidate for the cause of this disease outbreak, supported by both medical and scholarly opinions.
The first description of typhus was probably given in 1083 at La Cava abbey near Salerno, Italy. In 1546, Girolamo Fracastoro, a Florentine physician, described typhus in his famous treatise on viruses and contagion, De Contagione et Contagiosis Morbis.
Typhus was carried to mainland Europe by soldiers who had been fighting on Cyprus. The first reliable description of the disease appears during the siege of the Emirate of Granada by the Catholic Monarchs in 1489 during the Granada War. These accounts include descriptions of fever and red spots over arms, back and chest, progressing to delirium, gangrenous sores, and the stench of rotting flesh. During the siege, the Catholics lost 3,000 men to enemy action, but an additional 17,000 died of typhus.
Typhus was also common in prisons, where it was known as Gaol fever or Jail fever. Gaol fever often occurs when prisoners are frequently huddled together in dark, filthy rooms. Imprisonment until the next term of court was often equivalent to a death sentence. Typhus was so infectious that prisoners brought before the court sometimes infected the court itself. Following the Black Assize of Oxford 1577, over 510 died from epidemic typhus, including Speaker Robert Bell, Lord Chief Baron of the Exchequer. The outbreak that followed, between 1577 and 1579, killed about 10% of the English population.
During the Lent assize held at Taunton, typhus caused the death of the Lord Chief Baron of the Exchequer, the High Sheriff of Somerset, the sergeant, and hundreds of other persons. During a time when there were 241 capital offences, more prisoners died from 'gaol fever' than were put to death by all the public executioners in the realm. In 1759 an English authority estimated that each year a quarter of the prisoners had died from gaol fever. In London, typhus frequently broke out among the ill-kept prisoners of Newgate Gaol and moved into the general city population.

19th century

Epidemics occurred in the British Isles and throughout Europe, for instance, during the English Civil War, the Thirty Years' War, and the Napoleonic Wars. Many historians believe that the typhus outbreak among Napoleon's troops is the real reason why he stalled his military campaign into Russia, rather than starvation or the cold. A major epidemic occurred in Ireland between 1816 and 1819, and again in the late 1830s. Another major typhus epidemic occurred during the Great Irish Famine between 1846 and 1849. The Irish typhus spread to England, where it was sometimes called "Irish fever" and was noted for its virulence. It killed people of all social classes since lice were endemic and inescapable, but it hit particularly hard in the lower or "unwashed" social strata. It was carried to North America by the many Irish refugees who fled the famine. In Canada, the 1847 North American typhus epidemic killed more than 20,000 people, mainly Irish immigrants in fever sheds and other forms of quarantine, who had contracted the disease aboard coffin ships. As many as 900,000 deaths have been attributed to the typhus fever during the Crimean War in 1853–1856, and 270,000 to the 1866 Finnish typhus epidemic.
In the United States, a typhus epidemic struck Philadelphia in 1837. The son of Franklin Pierce died in 1843 of a typhus epidemic in Concord, New Hampshire. Several epidemics occurred in Baltimore, Memphis, and Washington, D.C. between 1865 and 1873. Typhus fever was also a significant killer during the American Civil War, although typhoid fever was the more prevalent cause of US Civil War "camp fever." Typhoid is a completely different disease from typhus. Typically more men died on both sides of disease than wounds.
Rudolph Carl Virchow, a physician, anthropologist, and historian attempted to control an outbreak of typhus in Upper Silesia and wrote a 190-page report about it. He concluded that the solution to the outbreak did not lie in individual treatment or by providing small changes in housing, food or clothing, but rather in widespread structural changes to directly address the issue of poverty. Virchow's experience in Upper Silesia led to his observation that "Medicine is a social science". His report led to changes in German public health policy.