Syphilis in Sub-Saharan Africa

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Introduction

Caitlin Barker.

Infamous throughout history as one of the most unpleasant, harmful, and silent of sexually transmitted diseases, Syphilis remains a major health issue in the world's most neglected and troubled regions. Although now relatively rare in the United States, with approximately 36,000 cases reported a year and only around 30 fatalities, an estimated 492,000 infants in Sub-Saharan Africa die each year from congenital syphilis [2].

Syphilis presents a severe diagnostic challenge to health care workers around the world, due to the broad and inconclusive nature of its symptoms. Furthermore, this “great imitator” of a disease can also remain unnoticed in infected people for years, thus helping it spread from person to person through sexual contact. Because of this, effective and cheap syphilis screening is essential to its eradication.

Just as syphilis tends to be most prevalent in some of the world's poorest places, it is also strongly correlated with the HIV virus. We will examine the ways in which syphilis can act as a facilitator for the deadly AIDS-causing virus, and how health workers are attempting to address this issue. We will also look at congenital syphilis, and why it is that such an easily-preventable disease still kills thousands every year.

Fig. 1 The syphilis bacterium, treponema pallidum attaching to a testicular cell. Source: The Encyclopedia Britannica, online.

Treponema Pallidum and Transmission

Syphilis is caused by infection of a bacterium called treponema pallidum, a bacterium of the spirochete phylum. Like all spirochetes, it is corkscrew-shaped and Gram-negative [5].After a person is infected with the bacterium through direct contact with a syphilis sore (which are often unrecognizable in certain stages), the incubation period for treponema pallidum can range from ten to ninety days, with an average of twenty-ones days before the first symptoms appear [1].

Transmission occurs primarily through sexual contact, and both oral, vaginal, and anal sex can result in transmission if a syphilis sore is allowed to come in contact with any mucous membranes of the infected persons' partner. This means that even when condoms are used properly, syphilis can still be spread if the sore is located in an area not covered by the condom. Because sores can be located on the lips and mouth as well as the external genitals, vagina, anus, and rectum, there are many possibilities for transmission. [5].

In addition to physical contact during sexual activity, it is also possible for infected pregnant women to pass it on to the baby they are carrying. Known as congenital syphilis, this is the cause of thousands of infant deaths in Sub-Saharan Africa, and must be treated quickly and effectively if the baby is to be saved. Due to the high likelihood of transmission from mother to fetus (scientists currently estimate that it is between 60% and 80%), women should be tested for syphilis before they become pregnant. [1].

Stages, Diagnosis, and Treatment

Primary Stage
After infection and the roughly month-long incubation period, the first external signs of syphilis appear. The beginning of the so-called “primary stage” of the infection is marked by the appearance of a chancre, or occasionally multiple chancres. Chancres are small, round, firm, sores which are usually painless and can often either go unnoticed or are mistaken for something else. They always appear at the spot where the syphilis bacterium, treponema pallidum, entered the body. Because the chancre will heal without any treatment after three to six weeks, many people mistakenly believe that the problem is gone, and they do not need to seek treatment. However, if the chancre was allowed to heal naturally, the infection will progress into the secondary stage. [4]

Secondary Stage
After the chancre heals, a rash will begin to develop on one or several areas of the body. This rash generally does not cause itching, and can often either appear to be a symptom of a great variety of other things, or be so faint that the infected person doesn't notice it. This, naturally, makes it difficult to diagnose correctly and contributes to the disease's nickname, the “great imitator”. However, the kind of rash most associated with syphilis is located on the palms of the hands and bottoms of the feet, and consists of characteristic rough, reddish brown spots.[1]
Although less common than the rash, other symptoms associated with the secondary stage of the infection include sore throat, headaches, weight loss, muscle aches, fever, and fatigue. Like the rash, these symptoms are certainly not unique to syphilis, and often do not aid in correct diagnosis of the disease. However, like the chancre, these symptoms will eventually disappear even without treatment, at which point the infection progresses to its final, latent stage.[4]

Late and Latent Stags
If the symptoms of the secondary stage are allowed to heal on their own, without treatment, the syphilis will enter its hidden, or latent stage. Eerily enough, this final and more serious stage is characterized by its complete invisibility and lack of symptoms. Although you cannot see it externally, the infection remains within the person, and can stay there for several years.[4]
In about 15% of syphilis patients, the disease progresses out of the latent stage after about ten to twenty years, and progresses to the latest stages of the infection. The symptoms of these are quite serious, and include damage of the internal organs, brain nerves, blood vessels, heart, eyes, joints, bones, and liver. People in the late stages of syphilis may also experience paralysis, numbness, gradual blindness, dementia, difficulty coordinating muscular movements, and sometimes even death.[4]

Diagnosis
If an infected person or their doctor is able to notice and identify a chancre, a special dark-field microscope can be used to detect the presence of syphilis bacteria in material removed from the chancre. However, another common method by which doctors are able to diagnose syphilis is through a simple blood test, which detects syphilis antibodies found in the blood stream shortly after infection [4].
For places where people do not have easy access to advanced microscopes or safe and accurate blood tests, a newly-developed syphilis screening test has recently been developed. Consisting of a treponemal antigen-impregnated strip of paper, all that is required of the patient is a simple finger prick, and results are given within just a few minutes. Because this method requires neither doctors, advanced equipment, nor refrigeration, efforts are being made to implement these cheap tests($0.93 to $1.44) in Sub-Saharan Africa, where diagnosis is the key to prevention. [3]

Treatment
If syphilis is caught in its early stages, treatment is very straightforward. For a person who has been infected with syphilis for less than a year, treatment consists solely of a single injection of intramuscular penicillin, a kind of antibiotic. Because some people are severely allergic to penicillin, they will need the addition of penicillin desensitization before they can undergo the standard treatment procedure. However, because there are no home remedies or over-the-counter drugs that can effectively cure syphilis, people allergic to penicillin have no alternatives [1]. It is important that the patient not partake in sexual behavior until the sores are completely healed, because even after penicillin injection, the sores are still contagious. Also, it is important to remember that people can become re-infected with syphilis, so safe sexual habits and frequent testing is strongly advised. [4]

Syphilis and HIV

As one can easily imagine, HIV and syphilis are strongly linked through the simple fact that both are sexually transmitted diseases obtained through dangerous sexual behavior. Thus, people who do not take the preventative measures necessary to protect themselves from one of the STDs are often at risk for the other as well. Furthermore, circumstances that facilitate high levels of HIV (such as limited access to health care and education and lack of women's rights) also contribute to high levels of other STDs, such as syphilis.

From a biological standpoint, however, there is a particularly strong correlation between HIV and syphilis, resulting in an estimated two-to-five-fold increase in contracting HIV if exposed to it when syphilis is also present [4]. First and foremost, the open sores produced by the syphilis virus are especially good places for the HIV virus to enter the body. In addition, infections such as syphilis that cause breaks in the protective layers of the body break down natural barriers against infection, and the fluid produced by syphilis sores is an excellent means by which to transmit both types of infections.[4]

Luckily, there is an upside to this connection between diseases. Health workers are now working to take advantage of syphilis treatments and screening as an opportunity to council or test the patients for HIV as well, since they are certainly high-risk individuals. The same is true for HIV patients, and many researchers believe that combining HIV treatments such as Prevention of Mother-To-Child-Treatment (PMTCT) with antenatal syphilis screening would prove to be more cost-effective [6].

Congenital Syphilis

Fig. 2 Symptoms of congenital syphilis in a newborn baby. Source: The New Zealand Medical Journal, online.

Congenital syphilis is a devastating disease that is responsible for between 20% and 30% of perinatal deaths in Sub-Saharan Africa [2]. Passed from an infected mother to her growing fetus, syphilis manifests itself in the newborn in much the same way it does in the adult: in three stages of increasing severity. Fig. 2 shows an example of Early Congenital Syphilis, in which the infant has bullous eruptions or a rash on the soles of their feet and palms of their hands, as well as the “old man” look, and fissured lesions all over the body [1]. Later congenital syphilis, which occurs once the child reaches roughly the age of two, can result in blindness, deafness,progressive intellectual deterioration, and death [1].

Luckily, adequate treatment during pregnancy cures both the mother and fetus almost 100% of the time. However, anywhere between 4% and 15% of women in Sub-Saharan Africa are infected with syphilis and the mother is often in the latent stage of syphilis when she becomes pregnant and thus has no idea she is infected [6]. Therefore, it is usually extremely difficult to carry out treatment during the pregnancy. Also, in order to treat congenital syphilis during pregnancy, the mother must take two doses of penicillin (as opposed to one, which is the standard for normal adult syphilis). Occasionally this drug therapy can lead to a severe reaction resulting in spontaneous abortion of the fetus, and so it is not without its dangers [7].

Conclusion

The potential for great harm to both the body of a person infected with Syphilis, as well as their fetus, if they are pregnant, is large enough that the infection should be regarded as a pressing issue in the global health world. Fortunately, syphilis is no longer a problem in the Western world, where it once ran rampant and killed thousands. Once a cure was discovered, however, public health workers and governments alike flew to action to cheaply and easily get rid of the nasty disease. Why, then, is it still so common in Sub-Saharan Africa? Due to the fact that it remains prevalent only in areas of the world which have already been marginalized for other reasons, such as extreme poverty, war, and disease, syphilis is largely ignored as an “less pressing” disease than HIV/AIDS. However, until syphilis is eradicated, HIV will continue to be spread easily via syphilis sores and identical forms of dangerous sexual behavior. Therefore, health workers around the world need to take advantage of newly-developed strategies and inventions (such as the on-the-spot syphilis test) to simultaneously fight both HIV and syphilis.

The Millennium Development Goals (MDGs), set down in 2001 and agreed to be achieved by 2015, call for a two-thirds reduction in child mortality [2]. It is unlikely that this goal will be met without the drastic re-organization of congenital syphilis prevention, which includes primarily universal syphilis screening in women. As with HIV and other STDs, testing for such a stigmatized infection is not easy, and will require increased education and funding. However, several recent studies have shown that widespread implementation of cheap but effective testing methods will save significant numbers of both lives and money, as well as provide health workers with yet another much-needed mechanism through which to address other pressing health issues, such as HIV/AIDS [7].

References

1. "Congenital Syphilis: Infections in Neonates: Merck Manual Professional." The Merck Manuals Online Medical Library. Merck and Co., n.d. Web. 7 Dec. 2009.

2. Peeling, Rosanna, David Mabey, Dan Fitzgerald, and Deborah Watson-Jones. "Avoiding HIV and Dying of Syphilis." The Lancet 364 (2004): 1561-1563. The Lancet. Web. 2 Dec. 2009.

3. "Prevention of Mother-to-Child Transmission of Syphilis." World Health Organization. N.p., n.d. Web. 6 Dec. 2009.

4."STD Facts - Syphilis." Centers for Disease Control and Prevention. CDC, n.d. Web. 7 Dec. 2009.

5. "Syphilis: eMedicine Infectious Diseases." eMedicine - Medical Reference. N.p., n.d. Web. 7 Dec. 2009.

6. Terris-Prestholt, F, D Watson-Jones, K Mugeye, and L Kumaranayake. "Is Antenatal Syphilis Screening Still Cost Effective in Sub-Saharan Africa." Sexually Transmited Infections 375.79 (2003): 375-381. Sexually Transmited Infections. Web. 4 Dec. 2009.

7. Watson-Jones, Deborah, Monique Oliff, Fern Terris-Prestholt, and John Changalucha. "Antenatal Syphilis Screening in Sub-Saharan Africa: Lessons Learned from Tanzania." Tropical Medicine and International Health 10 (2005): 934-943. Tropical Medicine and International Health. Web. 7 Dec. 2009.

Edited by student of Joan Slonczewski for BIOL 191 Microbiology, 2009, Kenyon College.