Epidemic typhus

Signs and symptoms

Symptoms include severe headache, a sustained high fever, cough, rash, severe muscle pain, chills, falling blood pressure, stupor, sensitivity to light, delirium and death. A rash begins on the chest about five days after the fever appears, and spreads to the trunk and extremities. A symptom common to all forms of typhus is a fever which may reach 39 °C (102 °F).

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 which recurs in someone after a long period of latency (similar to the relationship between chickenpox and shingles). This recurrence often occurs in times of relative immunosuppression, which is often in the context of malnutrition and other illnesses. In combination with poor sanitation and hygiene which leads to a greater density of lice, this reactivation is why typhus forms epidemics in times of social chaos and upheaval.

Transmission

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 disease is then transmitted to an uninfected human who scratches the louse bite (which itches) 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 hundreds of thousands of prisoners in Nazi concentration camps during World War II. The deteriorating quality of hygiene in camps such as Auschwitz, Theresienstadt, and Bergen-Belsen created conditions where diseases such as typhus flourished. 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.

Henrique da Rocha Lima in 1916 then proved that the bacterium Rickettsia prowazekii was the agent responsible for typhus; he named it after H. T. Ricketts and Stanislaus von Prowazek, two zoologists who had died from typhus while investigating epidemics. Once these crucial facts were recognized, Rudolf Weigl in 1930 was able to fashion a practical and effective vaccine production method by grinding 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.

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. Infection can also be prevented by vaccination.

Some of the simplest methods of prevention and treatment focus on preventing infestation of body lice. Complete change of 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 also left unworn and unwashed for 7 days also cause both lice and their eggs to die, as they have no access to their 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.

History

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.

Before a vaccine was developed during World War II, typhus was a devastating disease for humans and has been responsible for a number of epidemics throughout history. These epidemics tend to follow wars, famine, and other conditions that result in mass casualties.

During the second year of the Peloponnesian War (430 BC), the city-state of Athens in ancient Greece was hit by a devastating 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 a strong candidate for the cause of this disease outbreak, supported by both medical and scholarly opinions.

Typhus also arrived in Europe with soldiers who had been fighting on Cyprus. The first reliable description of the disease appears during the Spanish siege of Moorish Granada in 1489. 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 Spaniards lost 3,000 men to enemy action but an additional 17,000 died of typhus.

Typhus was also common in prisons (and in crowded conditions where lice spread easily), 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. It was so infectious that prisoners brought before the court sometimes infected the court itself. Following the Assize held at Oxford in 1577, later deemed the Black Assize, over 300 died from epidemic typhus, including Sir 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 Court held at Taunton (1730) typhus caused the death of the Lord Chief Baron, as well as the High Sheriff, the sergeant, and hundreds of others. 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 then moved into the general city population.

Epidemics occurred throughout Europe and occurred during the English Civil War, the Thirty Years' War and the Napoleonic Wars. During Napoleon's retreat from Moscow in 1812, more of his soldiers died of typhus than were killed by the Russians. A major epidemic occurred in Ireland between 1816–19, and again in the late 1830s, and yet 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. In Canada, the typhus epidemic of 1847 killed more than 20,000 people from 1847 to 1848, mainly Irish immigrants in fever sheds and other forms of quarantine, who had contracted the disease aboard coffin ships.

In America, a typhus epidemic killed the son of Franklin Pierce in Concord, New Hampshire in 1843 and struck in Philadelphia in 1837. 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.

Physician, anthropologist, historian Rudolph Carl Virchow’s attempt to control an outbreak of typhus in Upper Silesia and his subsequent 190 page report included the observation that the solution to the outbreak did not lie in individual treatment or small changes in housing, food or clothing provided, but rather in widespread structural changes that directly addressed the issue of poverty. Virchow’s experience in Upper Silesia led to the observation that “Medicine is a social science”. His report led to changes in German public health policy.

During World War I typhus caused three million deaths in Russia and more in Poland and Romania. Delousing stations were established for troops on the Western front but the disease ravaged the armies of the Eastern front, with over 150,000 dying in Serbia alone. Fatalities were generally between 10 and 40 percent of those infected, and the disease was a major cause of death for those nursing the sick. Between 1918 and 1922 typhus caused at least 3 million deaths out of 20–30 million cases. In Russia after World War I, during a civil war between the White and Red armies, typhus killed three million, largely civilians. During World War II typhus struck the German Army as it invaded Russia in 1941. In 1942 and 1943 typhus hit French North Africa, Egypt and Iran particularly hard. Typhus epidemics killed inmates in the Nazi Germany concentration camps; infamous pictures of typhus victims' mass graves can be seen in footage shot at Bergen-Belsen concentration camp. Thousands of prisoners held in appalling conditions in Nazi concentration camps such as Auschwitz, Theresienstadt, and Bergen-Belsen also died of typhus during World War II, including Anne Frank at the age of 15 and her sister Margot. Even larger epidemics in the post-war chaos of Europe were only averted by the widespread use of the newly discovered DDT to kill the lice on millions of refugees and displaced persons.

Following the development of a vaccine during World War II, epidemics have usually occurred in Eastern Europe, the Middle East and parts of Africa, particularly Ethiopia, where its eradication was the focus of major research efforts by Naval Medical Research Unit Five.

In one of its first major outbreaks since World War II, epidemic typhus reemerged in 1995 in a jail in N’Gozi, Burundi. This outbreak followed the outbreak of a civil war in 1993 that caused the displacement of 760,000 people. Refugee camps were crowded and unsanitary, often far from towns and medical services.

A 2005 study found discovered higher seroprevalence of R. prowazekii in homeless populations in two shelters in Marseille, France, noting the “hallmarks of epidemic typhus and relapsing fever”.

Biological weapon

Typhus was one of more than a dozen agents that the United States researched as potential biological weapons before President Richard Nixon suspended all non-defensive aspects of the U.S. biological weapons program in 1969.

Poverty and displacement

The CDC lists the following areas as active foci of human epidemic typhus: Andean regions of South America, some parts of Africa; on the other hand, the CDC only recognizes an active enzootic cycle in the United States involving flying squirrels (CDC). Though epidemic typhus is commonly thought to be restricted to areas of the developing world, serological examination of homeless persons in Houston found evidence for exposure to the bacterial pathogens that cause epidemic typhus and murine typhus. A study involving 930 homeless people in Marseilles, France found high rates of seroprevalence to R. prowazekii and a high prevalence of louse-borne infections in the homeless.

Typhus has been increasingly discovered in homeless populations in developed nations. Typhus among homeless populations is especially prevalent as these populations tend to migrate across states and countries, spreading the risk of infection with their movement. The same risk applies to refugees, who travel across country lines, often living in close proximity and unable to maintain necessary hygienic standards to avoid being at risk for catching lice possibly infected with typhus.

Because the typhus-infected lice live in clothing, the prevalence of typhus is also affected by weather, humidity, poverty and lack of hygiene. Lice, and therefore typhus, are more prevalent during colder months, especially winter and early spring. In these seasons, people tend to wear multiple layers of clothing, giving lice more places to go unnoticed by their hosts. This is particularly a problem for poverty-stricken populations as they often do not have multiple sets of clothing, preventing them from practicing good hygiene habits that could prevent louse infestation.

Due to fear of an outbreak of epidemic typhus, the US Government put a typhus quarantine in place in 1917 across the entirety of the US-Mexican border. Sanitation plants were constructed that required immigrants to be thoroughly inspected and bathed before crossing the border. Those who routinely crossed back and forth across the border for work were required to go through the sanitation process weekly, updating their quarantine card with the date of the next week’s sanitation. These sanitation border stations remained active over the next two decades, regardless of the disappearance of the typhus threat. This fear of typhus and resulting quarantine and sanitation protocols dramatically hardened the border between the US and Mexico, fostering scientific and popular prejudices against Mexicans. This ultimately intensified racial tensions and fueled efforts to ban immigrants to the US from the Southern Hemisphere because the immigrants were associated with the disease.

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