Syphilis: Epidemiology and Treatment - Essay Example

Syphilis is a sexually transmitted disease (STD) caused by Treponema pallidum. Its epidemiology has shown some changes especially its association with HIV, yet it is still a major health problem. Congenital syphilis is associated with high infant mortality and morbidity. Clinically syphilis passes into stages, primary, secondary, tertiary and latent syphilis. Penicillin is still the mainstay of treatment although there are alternatives. Syndromic treatment should be focused upon in countries where no diagnosis facilities are available. 1. Introduction The first report of a syphilis epidemic was in the mid 1490s when it occurred among French soldiers laying siege to Naples. Many famous historical characters thought to have died from or suffered from syphilis like Nietzsche, Beethoven, Lincoln, C. Columbus and Ivan the terrible. Yet, syphilis still represents a sizeable morbidity. Some factors are specifically blamed for the last 20 years outbreaks of syphilis, among which the increased internet use to find sex partners and the increased prevalence of methamphetamine substance abuse are predominant (Barry and Klausner 2006 pp.22&24). 2. Definition Syphilis is a chronic, yet, a curable infectious disease, caused by a spirochete (Treponema pallidum). The disease is sexually transmitted (STD); besides, the organism crosses the placental barrier infecting the foetus and causes congenital syphilis. Most patients, especially in early stages) are unmindful they have the disease, which caused the disease to reappear noticeably especially after the appearance of AIDS (WHO/TDR 2006 p. 8). 3. Epidemiology The WHO / TDR report (2006) estimates there are nearly 12 million new syphilis cases per year, the majority of which in south and south East Asia (33%), sub-Saharan Africa (25%) and Latin America. As Chen and colleagues (2007) suggested syphilis incidence rate are higher in rapidly developing countries, in China, the rate has increased 25 folds since the early 1990s. In the US, incidence rates show 25% increase since 2000 with Europe and Asia showing similar rise in incidence rates (Renton et al, p. 494). 3.1 Cycling of syphilis epidemics An epidemic cycling is an expression of the dynamics of an infectious disease, drawn by analysing longitudinal data sets of an infectious disease. Analysis may prove that temporal changes in data reflect a series of periodic, yet continuous fluctuations; alternatively, analysis may signify that only many outbreaks occurred (Breban et al 2008 p.577). Whether syphilis epidemics show cycling is a controversial question, Gersovitz and Hammer (2004) consider cycling is the result of social and behavioural human factors; while Grassly et al (2005) believe cycling is because of changes in the disease biology. Breban et al (2008) represent a group of researchers who advocate there is no convincing evidence that neither syphilis epidemics cycle nor the transmission model predict a cycling behaviour. 3.2 The changing pattern of syphilis epidemiology Peterman and colleagues (2005) observed the current epidemic in the US and Europe is mainly because of the increased incidence of infection in men having sex with other men (MSM), who are HIV infected and practicing unsafe sex. This represents a behavioral risk factor, which needs to address specifically. 3. Aetiology The causative microorganism is Treponema pallidum whose only natural vectors are humans, monkeys and higher apes. The organism is very thin to take gram stain; therefore, examination is by dark-field microscopy for wet mounts or by silver stain in fixed specimens. The bacterium has 6 to 14 spirals tapered at both ends. The organism is motile because of six axial fibrils, three attached at each end and all six overlap in the middle. Culture is very difficult and produces a very poor outcome; thus, is not clinically useful (Hook 2007 p.1683). Infection occurs mainly through sexual contact, non-sexual transmission occurs through transfusion of contaminated blood or trans-placental (Soares et al 2004 p. 2). 4. Natural History The incubation period of Treponema pallidum is 21 days in average (10 to 90 days). Firstly, a painless papule develops at the inoculation site, which ulcerates to form a clean-based ulcer (chancre). If untreated, the chancre stays for 2 to 6 weeks then heals. Several weeks later, the disease passes to a secondary stage with systemic manifestations of low-grade fever, headache, malaise, generalized lymphadenopathy and muco-cutaneous rash with possible involvement of visceral organs. This stage may occur in the presence of the healing primary chancre or alternatively, several months after its disappearance. Secondary lesions heal within 2 to 6 weeks, and infection passes to a latent phase. Relapsing lesion taking the form of either stages occur in 20% of cases of latent syphilis. In the pre-antibiotic era, third stage destructive lesions (gumma) involve mainly the eyes, the central nervous system, the heart, the palate, or the skin; occur in nearly one third of patients. When these lesions appear is variable and may take up to 25 years. Gumma lesions are now rare and are much less reported than in the past (Hook 2007 p.1683). 5. Diagnosis In addition to the clinical stages mentioned before, figure (1) (see appendix) illustrates the clinical manifestations of every syphilitic stage (Kent and Romanelli 2008 p. 228). Congenital syphilis is a multi-organ systemic disease that may cause grave consequences unless syphilitic mothers receive treatment in early pregnancy. Nearly 70% of syphilitic mothers transmit the disease to their foetuses and 40% of pregnancies of untreated mothers end in stillbirths. Treponema pallidum infects the foetus starting from 14th week of pregnancy; on delivery, many infants may not show specific signs. The earliest sign of disease is rhinitis (snuffles) similar to that of exanthemata by the age of 2 years, other early signs include maculopapular rash, jaundice with hepatosplenomegaly, Hutchinson's disease, interstitial keratitis and sensory-neural hearing loss. Saddle nose and perforated hard palate occur late and are manifestations of gumma stage (Walker and Walker 2007 p. 200). Table 2 (see appendix) shows the laboratory tests for diagnosing syphilis (Kent and Romanelli 2008 p. 230). 6. Treatment Penicillin still represents the mainstay of syphilis treatment, 2.4 mega-units benzathine penicillin administered intramuscular as a single dose; or weekly for two to three weeks is recommended. In case a patient is allergic to penicillin, the alternatives are 100 mg doxycycline b.i.d for two weeks, 500 mg tetracycline q.i.d for two weeks (Goh 2005 p. 450). Riedner et al (2005) suggested a 2 gm either single dose of azithromycin or divided into two doses separated by week duration is as effective as penicillin to treat syphilis. However, Katz and Klausner (2008) suggested that many cases of syphilis treatment with azithromycin are because of bacterial resistance developed against the drug. Patient follow up after treatment is as important as receiving treatment, which should be on clinical on serological grounds. Non-treponemal tests (VDRL and RPR) are commonly in use, as treponemal tests will maintain a false positive result for a long time although the disease may well be eradicated with effective treatment (Kent and Romanelli 2008 p. 232). In areas with no facilities to diagnose, or diagnosis costs are too high, syndromic management of syphilis and other similar diseases as chancroid or lymphogranuloma venereum are necessary. Although the protocol design is based on the geographical location and the main causes of genital ulcers, or STDs in that country, yet essentially it consists of benzathine penicillin in a single dose as described and a single dose of ciprofloxacin. Azithromycin in 1 gm single dose or erythromycin 500 mg q.i.d. for 1 week are good alternatives (Goh 2005 p.451). Table 3 (see appendix) shows the different treatment regimens for syphilis. Appendix Adapted from Kent and Romanelli (2008). Table 2: Tests for the diagnosis of syphilis (Kent and Romanelli 2008 p. 230). Table 3: Treatment regimens for syphilis (Kent and Romanelli 2008 p. 231). References Barry PM and Klausner JD, 2006. The impact of STIs. MLO Med Labs Obs, 38 (10), 22, 24-25. Breban R, Supervie V, Okano JT, Vardavas, R and Blower S, 2008. Is there any evidence that syphilis epidemics cycle Lancet Infect Dis, (8), 577-581. Chen ZQ, Zhang GC, Gong XD, Lin C et al, 2007. Syphilis in China: results of a national surveillance program. The Lancet, (369 (9556)), 132-138. Gersovitz M and Hammer JS, 2004. The economical control of infectious diseases. The Economic Journal, (114), 1-27. Goh BT, 2005. Syphilis in adults. Sexually Transmitted Infections, (81), 448-452. Grassly NC, Fraser C and Garnett GP, 2005. Host immunity and synchronized epidemics of syphilis across the United States. Nature, (433), 417-421. Hook EW, 2007. Chapter 340: Syphilis. In Ausiello DA and Goldman L, ed. Cecil Textbook of Medicine. St. Louis: Saunders. 1683-1685. Katz KA and Klausner JD, 2008. Azithromycin resistance in Treponema pallidum. Current Opinion in Infectious Diseases, (21), 83-91. Kent ME and Romanelli F, 2008. Reexamining Syphilis: An Update on Epidemiology, Clinical Manifestations and Management. Ann Pharmacother, (42), 226-236. Peterman TA, Heffelfinger JD, Swint EB and Groseclose SL, 2005. The Changing Epidemiology of Syphilis. Sexually Transmitted Diseases (October supplement), 32(10), S4-S10. Renton A, Gzirishvilli D, Gotsadze G and Godinho J, 2006. Epidemics of HIV and sexually transmitted infections in Central Asia: Trends, drivers and priorities for control. International Journal of Drug Policy, 17(6), 494-503. Riedner G, Rusizoka M, Todd J, Maboko L et al, 2005. Single-Dose Azithromycin versus Penicillin G Benzathine for the Treatment of Early Syphilis. N Engl J Med, (353), 1236-1244. Schmid G, 2004. Economic and programmatic aspects of congenital syphilis prevention. Bulletin of the World Health Organization, (82), 402-409. Soares AB, Gonzaga HFS, Jorge MA and Barraviera SR, 2004. Oral Manifestations of Syphilis: A Review. J. Venom Anim. Toxins incl. Trop. Dis., 10(1), 2-9. Walker GJA and Walker DG, 2007. Congenital syphilis: A continuing but neglected problem. Seminars in Fetal & Neonatal Medicine, (12), 198-206. WHO/TDR Special Program for Research & Training in Tropical Diseases, 2006. The use of Rapid Syphilis Tests [Online]. Available from: http://apps.who.int/tdr/svc/publications/tdr-research-publications/use-rapid-syphilis-tests, Not Available in Print Version. [Cited 4/08/2009] Read More