outbreak followed the start of the burundian civil war in 1993, which caused the displacement of 760,000 people. refugee camps were crowded and unsanitary, and often far from towns and medical services. 21st century a 2005 study found seroprevalence of r. prowazekii antibodies in homeless populations in two shelters in marseille, france. the study noted the "hallmarks of epidemic typhus and relapsing fever". history of vaccines major developments for typhus vaccines started during world war i, as typhus caused high mortality, and threatened the health and readiness for soldiers on the battlefield. vaccines for typhus, like other vaccines of the time, were classified as either living or killed vaccines. live vaccines were typically an injection of live agent, and killed vaccines are live cultures of an agent that are chemically inactivated prior to use. attempts to create a living vaccine of classical, louse-borne, typhus were attempted by french researchers but these proved unsuccessful. researchers turned to murine typhus to develop a live vaccine. at the time, murine vaccine was viewed as a less severe alternative to classical typhus. four versions of a live vaccine cultivated from murine typhus were tested, on a large scale, in 1934. while the french were making advancements with live vaccines, other european countries were working to develop killed vaccines. during world war ii, there were three kinds of potentially useful killed vaccines. all three killed vaccines relied on the cultivation of rickettsia prowazekii, the organism responsible for typhus. the first attempt at a killed vaccine was developed by germany, using the rickettsia prowazekii found in louse feces. the vaccine was tested extensively in poland between the two world wars and used by the germans for their troops during their attacks on the soviet union. a second method of growing rickettsia prowazekii was discovered using the yolk sac of chick embryos. germans tried several times to use this technique of growing rickettsia prowazekii but no effort was pushed very far. the last technique was an extended development of the previously known method of growing murine typhus in rodents. it was discovered that rabbits could be infected, by a similar process, and contract classical typhus instead of murine typhus. again, while proven to produce suitable rickettsia prowazekii for vaccine development, this method was not used to produce wartime vaccines. during wwii, the two major vaccines available were the killed vaccine grown in lice and the live vaccine from france. neither was used much during the war. the killed, louse-grown vaccine was difficult to manufacture in large enough quantities, and the french vaccine was not believed to be safe enough for use. the germans worked to develop their own live vaccine from the urine of typhus victims. while developing a live vaccine, germany used live rickettsia prowazekii to test multiple possible vaccines' capabilities. they gave live rickettsia prowazekii to concentration camp prisoners, using them as a control group for the vaccine tests. the use of ddt as an effective means of killing lice, the main carrier of typhus, was discovered in naples. society and culture 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 marseille, 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. literature (1847) in jane eyre by charlotte brontë, an outbreak of typhus occurs in jane's school lowood, highlighting the unsanitary conditions the girls live in. (1862) in fathers and sons by ivan turgenev, evgeny bazarov dissects a local peasant and dies after contracting typhus. (1886) in the short story "excellent people" by anton chekhov, typhus kills a russian provincial. (1886) in the strange adventures of captain dangerous by george augustus henry sala: "we convicts were all had to the grate, for the knight and alderman would not venture further in, for fear of the gaol fever;" (1890) in how the other half lives by jacob riis, the effects of typhus fever and smallpox on "jewtown" are described. (1935) hans zinsser's rats, lice and history, although a touch outdated on the science, contains many useful cross-references to classical and historical impact of typhus. (1940) in the don flows home to the sea by mikhail sholokhov, numerous characters contract typhus during the russian civil war. (1946) in viktor frankl's man's search for meaning, frankl, a nazi concentration camp prisoner and trained psychiatrist, treats fellow prisoners for delirium due to typhus, while being occascionally affected with the disease himself. (1955) in vladimir nabokov's lolita, humbert humbert's childhood sweetheart, annabel leigh, dies of typhus. (1956) in doctor zhivago by boris pasternak, the main character contracts epidemic typhus in the winter following the russian revolution, while living in moscow. (1964) in nacht (novel) by edgar hilsenrath, characters imprisoned in a ghetto in transnistria during world war ii are portrayed infected with and dying of epidemic typhus. (1978) in patrick o'brian's novel desolation island, an outbreak of "gaol-fever" strikes the crew while sailing aboard the leopard. (1980–1991) in maus by art spiegelman, vladek spiegelman contracts typhus during his imprisonment at the dachau concentration camp. (1982) there is a typhus epidemic in chile graphically described in the house of the spirits by isabel allende (1996) in andrea barrett's novella ship fever, the characters struggle with a typhus outbreak at the canadian grosse isle quarantine station during 1847. (2001) lynn and gilbert morris' novel where two seas met portrays an outbreak of typhus on the island of bequia in the grenadines, in 1869. (2004) in neal stephenson's the system of the world, a fictionalized sir isaac newton dies of "gaol fever" before being resurrected by daniel waterhouse.