Once thought to be on the verge of extinction, syphilis began a resurgence in the Lower Mainland in the summer of 1997. According to the health board, it is centered (approximately two-thirds of known cases) among sex trade workers in the Downtown Eastside of Vancouver and their sexual contacts. Traditional public health control measures previously employed against this disease failed to control the outbreak. The mass azithromycin treatment initiative (targeting 4,000 people in each of the two weeks) is intended to interrupt disease transmission in the high-risk groups through treatment of incubating or infectious syphilis. Azithromycin was chosen for this initiative because it can be given orally and has fewer side effects than the standard syphilis treatment of IM bicillin.

The health board intends to conduct extensive follow-up studies in order to determine the effectiveness of the mass treatment program. More formal studies will also be undertaken by the BC Centre for Disease Control, with the results not expected to be released until sometime this autumn.

Several recent studies link syphilis with an increased likelihood of transmission of HIV. These studies demonstrated that in a sexual partnership involving individuals where one was HIV-negative and the other positive, the probability of transmission of HIV was likely to be higher when another sexually transmitted disease (STD) is present in one or both individuals. This heightened probability of HIV transmission, called the ‘cofactor effect’, is especially pronounced for STDs such as syphilis.

For those unfamiliar with the disease or perhaps needing a brief refresher course, syphilis is a systemic illness caused by a corkscrew-shaped bacterium known scientifically as Treponema pallidum. The bacterium requires moisture to exist, so continuous moisture is a necessity for the transfer of the microorganism from one person to another. The most common means of such transmission is sexual intercourse, and it is this dependence on moisture that classifies syphilis as an STD. In the body’s tissues the bacteria reproduce and remain present for the lifetime of the infected person unless destroyed by treatment.

It is important to note that a person infected with syphilis may exhibit no outward symptoms. However, in most cases following initial infection a sore develops anywhere from 10 to 90 days later, and may appear on any part of the body that has been in contact with the sexual fluids of the person transmitting the disease. Sometimes, the sore will not be noticed. In both men and women, the sore will go away on its own within 10 to 40 days, leaving no scar.

After this initial phase of the disease, about half the persons infected will exhibit clinical manifestations characteristic of the second stage of syphilis, notably a rash typically appearing anywhere from four to eight weeks after the appearance of the sore. It may look like other rashes, like measles. It can appear anywhere on the body, but is most often found on the belly, genitals, palms of the hands and soles of the feet.

Following the secondary phase, a latent period ensues that may last from a few months to a lifetime, during which no outward sign of syphilis is recognisable. While most patients with latent syphilis do not progress any further, about one in four may be expected to develop the third and final stage of the disease, also known as tertiary syphilis. About half of those who go on to this stage will become incapacitated or die. Moreover, if left untreated syphilis can spread and cause damage to the brain, heart and other organs. Pregnant women can pass it to an unborn child with severe consequences.

A particularly virulent and malignant strain of syphilis known as Lues Maligna (hereafter referred to as "malignant" syphilis), has recently been observed on the increase among HIV-infected individuals, especially those who are also intravenous drug users. It is characterised as an explosive, widespread form of secondary syphilis whose symptoms include fever, headache and muscle pain along with the appearance of grotesque multiple lesions on the skin. Malignant syphilis typically develops six weeks to one year after primary infection, and seems to be affect men more than women. It also tends to attack the liver, and researchers have also identified a correlation between malignant syphilis and hepatitis.

If treated aggressively the outcome of persons who develop malignant syphilis is usually good. However, in rare cases fatalities have been reported despite treatment with penicillin. Ironically azithromycin, the drug being used as part of the Vancouver mass treatment campaign, was found to be ineffective in combating malignant syphilis in a penicillin allergic patient, according to a recent study. In this particular case physicians were ultimately successful in treating the disease through a combination of other drugs. Since only a very small number of people are actually allergic to penicillin, and an even smaller percentage suffer from the malignant form of the disease, no significant impact on the efficacy of the treatment program is expected.