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Why syphilis infection rates oscillate
Newsdesk
denied treatment for syphilis]. If the same system is giving prevention messages, it’s likely that the messages won’t be trusted”, says lead author Laura Bogart, a health psychologist at the RAND Corporation. Bogart and colleagues conducted a telephone survey of 500 black Americans aged 15–44 across the USA. Those surveyed were asked whether they agreed or disagreed with a series of questions about HIV/AIDS beliefs. The authors found that more black men than women believe in conspiracy theories, and that those who do are significantly less likely to use condoms regularly. Phil Wilson, executive director of the Black AIDS Institute in Los Angeles, CA, notes that: “Conspiracy
theories create an environment of fatalism, disempower people, and allow them to not take personal responsibility—all of which undermine condom use”. People who believe the government is “out to get them” no matter what they do are less likely to use a condom, Wilson told TLID. “As for disempowerment, if I feel like I don’t have the power to protect myself, or that my life is not worth protecting, then I’m not going to undermine my pleasure with a condom. Finally, if I’m convinced there’s this big bogeyman out there, it’s not my fault if I get infected with HIV/AIDS, so I don’t need to worry about wearing a condom.” The fact that African Americans who believe in the conspiracy are dismissed
out of hand or considered “crazy” compounds the problem, Wilson continued. “We have to acknowledge that there is an experience base that leads to a conspiracy theory; it doesn’t come out of folklore. Slavery was real, Tuskegee was real, other forms of brutality and discrimination are real.” Solutions include bolstering the black AIDS infrastructure and “increasing the number of credible black voices that are dealing with HIV/AIDS”, Wilson suggests. “Most importantly, whether HIV/AIDS is a conspiracy or not, African Americans are dying of this disease. We have to find a way to save our lives without regard to where virus came from.”
Marilynn Larkin
Why syphilis infection rates oscillate
http://infection.thelancet.com Vol 5 March 2005
chronised between US cities with time, suggesting an increasingly connected countrywide sexual network. Grassly believes that the development of partial immunity to syphilis explains the oscillating infection rates. Immediately after an epidemic, he explains, herd immunity is high and the infection cannot easily spread. Over time, immunity dwindles in previously exposed individuals and younger, unexposed people become sexually active. Eventually, population immunity is low enough to allow a new epidemic to occur. Gonorrhoea infections do not induce immunity, so gonorrhoea incidence does not oscillate like that of syphilis, he says. However, comments Matthew Golden (University of Washington Center for AIDS and STD, Seattle, WA, USA), “the syphilis epidemic currently affecting MSM throughout the developed world is not adequately explained by periodicity. Most of the available evidence suggests that MSM’s behaviour has changed and enhanced efforts to persuade persons at risk to adopt safer sexual behaviours remain critical.”
Rights were not granted to include this image in electronic media. Please refer to the printed journal.
Jackie Lewin, EM Unit, Royal Free Hospital/SPL
Cyclical oscillations in the incidence of syphilis in the USA over the past half century may be explained by considering how the infectious agent interacts with its host, rather than by invoking exogenous factors, such as changes in sexual behaviour (Nature 2005; 433: 417–20). However, stresses Nicholas Grassly (Imperial College London, UK), “our results do not mean that the current epidemic in syphilis among men who report sex with men [MSM] is due only to natural causes. This epidemic, at least partly, reflects increases in risky behaviour.” To study the link between sexual behaviour and the incidence of sexually transmitted diseases, Grassly and coworkers examined US syphilis and gonorrhoea incidence data collected between 1941 and 2002. “When we started this work”, explains Grassly, “we expected the syphilis and gonorrhoea incidences to show similar patterns”. Instead, gonorrhoea infection rates remained pretty constant over the study period, but syphilis rates oscillated with a 8–11-year periodicity. In addition, these oscillations became more syn-
A colony of Treponema pallidum, the cause of syphilis
The involvement of partial immunity in the dissemination of syphilis in populations is worth highlighting, adds Sevgi Aral (US Centers for Disease Control and Prevention, Atlanta, GA, USA), “but timely and accurate diagnosis and treatment, and reduction of high-risk behaviours remain our most important prevention and control tools”.
Jane Bradbury 135
denied treatment for syphilis]. If the same system is giving prevention messages, it’s likely that the messages won’t be trusted”, says lead author Laura Bogart, a health psychologist at the RAND Corporation. Bogart and colleagues conducted a telephone survey of 500 black Americans aged 15–44 across the USA. Those surveyed were asked whether they agreed or disagreed with a series of questions about HIV/AIDS beliefs. The authors found that more black men than women believe in conspiracy theories, and that those who do are significantly less likely to use condoms regularly. Phil Wilson, executive director of the Black AIDS Institute in Los Angeles, CA, notes that: “Conspiracy
theories create an environment of fatalism, disempower people, and allow them to not take personal responsibility—all of which undermine condom use”. People who believe the government is “out to get them” no matter what they do are less likely to use a condom, Wilson told TLID. “As for disempowerment, if I feel like I don’t have the power to protect myself, or that my life is not worth protecting, then I’m not going to undermine my pleasure with a condom. Finally, if I’m convinced there’s this big bogeyman out there, it’s not my fault if I get infected with HIV/AIDS, so I don’t need to worry about wearing a condom.” The fact that African Americans who believe in the conspiracy are dismissed
out of hand or considered “crazy” compounds the problem, Wilson continued. “We have to acknowledge that there is an experience base that leads to a conspiracy theory; it doesn’t come out of folklore. Slavery was real, Tuskegee was real, other forms of brutality and discrimination are real.” Solutions include bolstering the black AIDS infrastructure and “increasing the number of credible black voices that are dealing with HIV/AIDS”, Wilson suggests. “Most importantly, whether HIV/AIDS is a conspiracy or not, African Americans are dying of this disease. We have to find a way to save our lives without regard to where virus came from.”
Marilynn Larkin
Why syphilis infection rates oscillate
http://infection.thelancet.com Vol 5 March 2005
chronised between US cities with time, suggesting an increasingly connected countrywide sexual network. Grassly believes that the development of partial immunity to syphilis explains the oscillating infection rates. Immediately after an epidemic, he explains, herd immunity is high and the infection cannot easily spread. Over time, immunity dwindles in previously exposed individuals and younger, unexposed people become sexually active. Eventually, population immunity is low enough to allow a new epidemic to occur. Gonorrhoea infections do not induce immunity, so gonorrhoea incidence does not oscillate like that of syphilis, he says. However, comments Matthew Golden (University of Washington Center for AIDS and STD, Seattle, WA, USA), “the syphilis epidemic currently affecting MSM throughout the developed world is not adequately explained by periodicity. Most of the available evidence suggests that MSM’s behaviour has changed and enhanced efforts to persuade persons at risk to adopt safer sexual behaviours remain critical.”
Rights were not granted to include this image in electronic media. Please refer to the printed journal.
Jackie Lewin, EM Unit, Royal Free Hospital/SPL
Cyclical oscillations in the incidence of syphilis in the USA over the past half century may be explained by considering how the infectious agent interacts with its host, rather than by invoking exogenous factors, such as changes in sexual behaviour (Nature 2005; 433: 417–20). However, stresses Nicholas Grassly (Imperial College London, UK), “our results do not mean that the current epidemic in syphilis among men who report sex with men [MSM] is due only to natural causes. This epidemic, at least partly, reflects increases in risky behaviour.” To study the link between sexual behaviour and the incidence of sexually transmitted diseases, Grassly and coworkers examined US syphilis and gonorrhoea incidence data collected between 1941 and 2002. “When we started this work”, explains Grassly, “we expected the syphilis and gonorrhoea incidences to show similar patterns”. Instead, gonorrhoea infection rates remained pretty constant over the study period, but syphilis rates oscillated with a 8–11-year periodicity. In addition, these oscillations became more syn-
A colony of Treponema pallidum, the cause of syphilis
The involvement of partial immunity in the dissemination of syphilis in populations is worth highlighting, adds Sevgi Aral (US Centers for Disease Control and Prevention, Atlanta, GA, USA), “but timely and accurate diagnosis and treatment, and reduction of high-risk behaviours remain our most important prevention and control tools”.
Jane Bradbury 135