Editing Epidemic typhus (section)

=== 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.<ref name=":2">{{Cite journal|last=Lindenmann|first=Jean|date=2002|title=Typhus Vaccine Developments from the First to the Second World War (On Paul Weindling's 'Between Bacteriology and Virology...')|journal=History and Philosophy of the Life Sciences|publisher=Stazione Zoologica Anton Dohrn – Napoli|volume=24|issue=3–4|pages=467–485|doi=10.1080/03919710210001714513|pmid=15045834|JSTOR=}}</ref> Vaccines for typhus, like other vaccines of the time, were classified as either living or killed vaccines.<ref name=":2"/> 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.<ref name=":2"/>

Attempts to create a living vaccine of classical, [[louse]]-borne, typhus were attempted by French researchers but these proved unsuccessful.<ref name=":2"/> Researchers turned to [[murine typhus]] to develop a live vaccine.<ref name=":2"/> 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.<ref name=":2"/>

While the French were making advancements with live vaccines, other European countries were working to develop killed vaccines.<ref name=":2"/> During [[World War II]], there were three kinds of potentially useful killed vaccines.<ref name=":2"/> All three killed vaccines relied on the cultivation of ''[[Rickettsia prowazekii]]'', the organism responsible for typhus.<ref name=":2"/> The first attempt at a killed vaccine was developed by [[Germany]], using the ''[[Rickettsia prowazekii]]'' found in louse feces.<ref name=":2"/> 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]].<ref name=":2"/>

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.<ref name=":2"/>

The last technique was an extended development of the previously known method of growing murine typhus in rodents.<ref name=":2"/> It was discovered that rabbits could be infected, by a similar process, and contract classical typhus instead of murine typhus.<ref name=":2"/> Again, while proven to produce suitable ''[[Rickettsia prowazekii]]'' for vaccine development, this method was not used to produce wartime vaccines.<ref name=":2"/>

During WWII, the two major vaccines available were the killed vaccine grown in lice and the live vaccine from [[France]].<ref name=":2"/> Neither was used much during the war.<ref name=":2"/> 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.<ref name=":2"/>

The Germans worked to develop their own live vaccine from the urine of typhus victims.<ref name=":2"/> While developing a live vaccine, Germany used live ''[[Rickettsia prowazekii]]'' to test multiple possible vaccines' capabilities.<ref name=":2"/> They gave live ''[[Rickettsia prowazekii]]'' to concentration camp prisoners, using them as a control group for the vaccine tests.<ref name=":2"/>

The use of [[DDT]] as an effective means of killing lice, the main carrier of typhus, was discovered in [[Naples]].<ref name=":2"/>