Cases of syphilis doubled from three to six.
There were more cases of syphilis reported, and fewer cases of lead poisoning.
There were 202 reported cases of syphilis in the first six months of the year, Ms. Mullin said.
Cases of syphilis have been on the rise in the US since 2000, with men who have unprotected sex with men especially susceptible, according to the CDC.
By the end of the 1930s, there were 500,000 new cases of syphilis and 700,000 of gonorrhea in the United States every year.
Since 2010 the number of cases of syphilis in Londoners has increased by 163%, with a 22% increase in the year from 2014 to 2015.
Blacks and Hispanics accounted for most new cases of syphilis, according to the city's recent survey, but whites experienced faster rates of increase.
New cases of syphilis are at an all-time low, dropping to 7,000 last year from 50,000 in 1990.
Reported cases of syphilis, known in the south as "Guangdong boils," have increased more than tenfold in the last decade, according to national statistics.
Cases of syphilis in 45 to 64 year-olds rose ten-fold from just 52 in 2000 to 503 in 2009.
Earlier this month, the city's Department of Health and Mental Hygiene reported that in the first 13 weeks of 2007, cases of syphilis more than doubled to 260 from 128 in the same period a year ago.
