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.