In the English language Wikipedia article on the Recreation and Amusement Association, an organization for prostitution to Allied troops occupying Japan after World War II, it's claimed that sexually transmitted disease was rampant amongst the troops occupying Japan:
From the beginning of the Occupation, some Allied military officials cooperated with the Japanese government's system. According to the governors of Chiba and Kanagawa prefectures, American commanders contacted them in September 1945 and requested the establishment of brothels for their troops, offering US military police help if necessary. American medical officers established prophylactic stations in red-light districts and inside the larger brothels that distributed tens of thousands of condoms a week.
Despite these precautions, the problem of sexually transmitted diseases (STDs; primarily gonorrhea and syphilis) became a serious public health issue. By early 1946, nearly a quarter of all US occupation forces were estimated to be infected, and nearly half of some units. The Australian 34th Infantry Brigade had a rate of 55% infection. [emphasis added]
In response, GHQ imposed strict STD check procedures for prostitutes, placed certain brothels with high rates of infection off-limits to troops, and helped re-establish clinics and laboratories (many of which had been destroyed during the war) to diagnose infections. Most importantly, the 8th Army authorized the free dispersal of penicillin to infected prostitutes despite a serious shortage of the drug in the US and orders from Washington that it only be given to Japanese "as a life saving measure."
Citation 31 is "Tanaka Yuki (2002). Japan's Comfort Women: Sexual Slavery and Prostitution During World War II and the U.S. Occupation. Routledge.". This book received a mixed review at http://intersections.anu.edu.au/issue9/morris_review.html . Not universally bad, not universally good.
I'm skeptical that infection rates were as high as was claimed. (This is regarding allied troops from western countries such as Australia and the United States, not the Soviet Union)
For the high rates to occur, a very high proportion of soldiers would be having sex with someone who they weren't married to, and either not be using condoms, or have had their condoms fail on them.
Sex outside of marriage, let alone sex with a prostitute, would go against the Christian or Jewish religious norms of most western allied troops of that era. In addition, unless condoms were failing at a massive rate, a high infection rate would indicate that a lot of soldiers were choosing not to use sexual protection even with women who have a lot of partners.
The motivation I suspect for inflated numbers is to make western countries look bad, and also to make Japan's actions during World War II seem not so bad in comparison.
Was the rate of sexually transmitted disease as high as 55% in allied troops from western countries?