How Does Syphilis Transmission Occur?

Syphilis is a chronic, systemic sexually transmitted disease caused by Treponema pallidum. It is mainly transmitted through sexual routes and can be clinically manifested as primary syphilis, secondary syphilis, tertiary syphilis, latent syphilis, and congenital syphilis (fetal syphilis). It is a disease class listed in the "Control Law of the People's Republic of China on Infectious Diseases" as a category B prevention and management.

Yang Xueyuan	(Chief physician) audit	Dermatological Hospital of Chinese Academy of Medical Sciences
Wang Qianqiu	(Researcher) Review	Department of Sexually Transmitted Diseases, Chinese Academy of Medical Sciences

English name: syphilis
Visiting department: dermatology

Contagious: Have
way for spreading: Sexual transmission, mother and child

Syphilis Epidemiology

Syphilis is prevalent worldwide. According to WHO estimates, there are approximately 12 million new cases worldwide each year, mainly in South Asia, Southeast Asia, and sub-Saharan Africa. In recent years, syphilis has grown rapidly in China and has become the most reported STD with the highest number of reported cases. Of the reported syphilis, latent syphilis predominates, primary and secondary syphilis are also more common, and the number of reported cases of congenital syphilis is also increasing.

Treponema pallidum is contained in the skin and mucous membranes of patients with syphilis. In the case of sexual contact with patients with syphilis, patients without syphilis can get disease if the skin or mucous membrane is slightly damaged. Rarely can be transmitted by blood transfusion or route. Acquired syphilis (nurtured) Early syphilis patients are the source of infection. More than 95% of them are transmitted through dangerous or unprotected sex, and a few are transmitted through kissing, blood transfusion, and contaminated clothing. Fetal syphilis is transmitted by pregnant women with syphilis. If pregnant women with first, second and early latent syphilis have a higher chance of transmitting to the fetus.

Source of infection

Syphilis is a disease unique to humans. Patients with dominant and recessive syphilis are the source of infection. The skin lesions, secretions, and blood of Treponema pallidum are contained in people infected with syphilis. The first two years after infection are most contagious, and the sexually transmitted infections have fallen significantly after four years. Treponema pallidum can be transmitted to the fetus through the placenta, and pregnant women with early syphilis are at great risk of transmitting it to the fetus.

2. Ways of transmission

Sexual contact is the main route of transmission of syphilis, accounting for more than 95%. Early infection with syphilis is most contagious. With the prolongation of the disease, the infectivity is getting smaller and smaller, and the infectivity of sexual contact more than 4 years after infection is generally considered very weak.

Pregnant women with syphilis can be transmitted to the fetus through the placenta, causing intrauterine infection of the fetus, which can cause miscarriage, premature birth, stillbirth, or childbirth. It is generally believed that the earlier the period of syphilis in pregnant women, the greater the chance of infection to the fetus. Pregnant women are contagious even with asymptomatic recessive syphilis.

Clinical manifestations of syphilis

Acquired dominant syphilis

(1) The hallmark clinical feature of primary syphilis is hard chancre. Common sites are penis, glans, coronal sulcus, foreskin, urethral opening; labia majora, clitoris, cervix; anus, anal canal, etc. Can also be found on the lips, tongue, breasts, etc. Hard chancre is characterized by the appearance of 7 to 60 days after TP infection. Most patients have a single, non-painful, itchy, round or oval ulcer with clear borders, which is higher than the skin surface, and the sore surface is cleaner. Secondary infections have more secretions. There is cartilage-like hardness when touched. It lasts for 4 to 6 weeks and can heal itself. Hard chancre can coexist with secondary syphilis, and it must be distinguished from genital ulcer diseases such as soft chancre, genital herpes, and fixed drug rash. 1 to 2 weeks after the swollen lymph nodes appear in the chin, some patients have inguinal or swollen lymph nodes, which can be single or multiple. Painless.

(2) Second- stage syphilis is characterized by second-stage syphilis and has systemic symptoms. It usually recurs after an asymptomatic period after the hard chancre subsides. TP spreads with blood circulation, causing multiple site damage and multiple lesions. Invasion of skin, mucous membranes, bones, internal organs, cardiovascular, nervous system. When syphilis entered the second phase, the syphilis serology test was almost 100% positive. Systemic symptoms occur before the rash, fever, headache, sore joints, enlarged liver and spleen, and enlarged lymph nodes. The incidence is about 25% in men; about 50% in women. 3 to 5 days improved. Syphilis rash followed, and it recurred. Skin syphilis occurs in 80% to 95% of patients. It is characterized by diverse and recurrent rash types, widespread and symmetrical, painless and itchy, leaving no scars after healing, and rapid extinction treatment. The main types of rashes are spot-like, pimples-like, pustular syphilis, genital warts, and palmar syphilis. Recurrent syphilis After the initial resolution of syphilis, about 20% of patients with secondary syphilis relapse within one year, with circular pimples being the most common. Mucosal damage Mucosal damage occurs in about 50% of patients. Occurs in the lips, mouth, tonsils, and throat. It is a mucosal plaque or mucositis with exudate, or a gray-white membrane and redness and swelling. Syphilitic hair loss accounts for about 10% of patients. Most are sparse, with unclear boundaries, such as worm-like; a few are diffuse. bone and joint damage periostitis, osteitis, osteomyelitis and arthritis. With pain. Secondary eye syphilis Syphilitic iritis, iridocyclitis, choroiditis, retinitis, etc. Often bilateral. Second stage neurosyphilis has no obvious symptoms, cerebrospinal fluid is abnormal, and cerebrospinal fluid is positive for RPR. May have meningitis or meningovascular symptoms. Superficial lymphadenopathy

(3) Tertiary syphilis occurs in 1/3 of untreated dominant TP infections. Among them, 15% are benign late syphilis, and 15% to 20% are severe late syphilis. Skin and mucous membrane damage Nodular syphilis occurs in the scalp, scapula, back and limbs. Gum swollen often occurs in the lower leg, forming deep ulcers and atrophic scars; when it occurs in the forehead, tissue necrosis and perforation; in the case of nasal epiphysis, bone destruction occurs, forming saddle nose; Puncture ulcer; vaginal damage is the appearance of ulcers, which can form bladder vaginal leakage or rectal vaginal leakage. Proximal joint nodules are subcutaneous fibrous nodules that grow slowly in syphilitic fibroids. The symmetry, size varies, firmness, inactivity, no ulceration, normal epidermis, no inflammation, no pain, and can be eliminated. Cardiovascular syphilis mainly invades the aortic arch. Aortic insufficiency can occur, causing syphilis heart disease. The incidence of neurosyphilis is about 10%, which can occur in the early stage or several years, or ten years later. Asymptomatic, syphilitic meningitis, cerebrovascular syphilis, meningeal gum-like swelling, and paralytic dementia can occur. Meningeal swollen meninges are lesions involving one side of the cerebral hemisphere, with symptoms such as increased intracranial pressure, headache, and local brain compression. Parenchymal neurosyphilis is a substantial lesion of the brain or spinal cord. The former forms paralytic dementia. The latter is manifested as degenerative changes in the posterior root and posterior cord of the spinal cord.

2. Acquired recessive syphilis

Acquired TP does not form a dominant syphilis and is asymptomatic, or the symptoms of the syphilis subsides temporarily after a certain period of activity. A positive syphilis serum test and normal cerebrospinal fluid examination are called recessive (latent) syphilis. Early latent syphilis within 2 years after infection; late latent syphilis within 2 years after infection.

3. Pregnancy Syphilis

Pregnancy syphilis is a dominant or recessive syphilis that occurs during pregnancy. During syphilis during pregnancy, TP can be passed to the fetus through the placenta or umbilical vein, forming congenital syphilis in babies born later. The occurrence of arteritis in pregnant women leads to necrosis of placental tissue, which causes miscarriage, premature birth and stillbirth. Only a few pregnant women can give birth to healthy children.

4. Congenital dominant syphilis

(1) Early congenital syphilis The child was thin at birth, symptoms appeared 3 weeks after birth, and lymph nodes were enlarged throughout the body, without adhesion, pain, and stiffness. More syphilitic rhinitis. About 6 weeks after birth, skin lesions appear, which are blister-bulous skin lesions (syphilis pemphigus) or maculopapular, papular scaly lesions. Osteochondritis and periostitis can occur. More liver and spleen enlargement. Thrombocytopenia and anemia. Neurosyphilis can occur. No hard diarrhea occurred.

(2) Late congenital syphilis occurs after 2 years of age. One type is permanent damage to bone, teeth, eyes, nerves and skin caused by early lesions, such as saddle nose, Hao Qinsen teeth, etc., without activity. The other is the clinical manifestations caused by active damage, such as keratitis, neurological hearing loss, abnormal neurological manifestations, changes in cerebrospinal fluid, hepatosplenomegaly, nasal or jaw gum swelling, hydrocephalus, periostitis, Inflammation and skin and mucosal damage.

5. Congenital Latent Syphilis

Born in a mother with syphilis, there is no treatment and no clinical manifestations, but syphilis is seropositive. Those younger than 2 years old are early congenital latent syphilis, and those older than 2 years old are late congenital latent syphilis.

Syphilis diagnosis

Epidemiological history

History of unsafe sexual contact; history of maternal syphilis infection; history of blood transfusion.

2. Clinical manifestations

There are corresponding clinical manifestations of each stage of syphilis. If it is latent syphilis, it has no obvious clinical manifestations.

3. Laboratory inspection

(1) Dark-field microscopy Take the patient's suspicious skin lesions (such as hard chancre, condyloma acuminatum, wet pimples, etc.), check under a dark-field microscope, and see the movable Treponema pallidum, which can be used as the basis for the diagnosis of syphilis.

(2) Serological tests for syphilis There are many methods for serological tests for syphilis. The antigens used are two types of antigens: non-spirospiral antigen (cardiolipin antigen) and Treponema pallidum specific antigen. The former includes rapid plasma reagin ring card test (RPR), toluidine red unheated serology test (TRUST), etc., which can be used for quantitative tests to determine the efficacy and the degree of disease activity. The latter include Treponema pallidum particle agglutination test (TPPA), Treponema pallidum enzyme-linked immunosorbent assay (TP-ELISA), etc., which have strong specificity and are used for confirmation of TP infection.

Detection of Treponema pallidum IgM antibodies: After infection with syphilis, IgM antibodies first appear, and as the disease progresses, IgG antibodies then appear and slowly rise. After effective treatment, IgM antibodies disappeared, while IgG antibodies persisted. TP-IgM antibody cannot pass through the placenta. If the baby is positive for TP-IgM, it means that the baby has been infected. Therefore, the detection of TP-IgM antibody is of great significance for the diagnosis of fetal syphilis.

(3) Cerebrospinal fluid examination Cerebrospinal fluid examination should be performed in patients with syphilis who have neurological symptoms, or those who have failed to treat syphilis. This test is helpful for the diagnosis, treatment and prognosis of neurosyphilis. Inspection items should include: cell count, total protein determination, RPR and TPPA tests.

Differential diagnosis of syphilis

1. Hard chancre of primary syphilis should be distinguished from soft chancre, fixed drug eruption, and genital herpes.

2. Primary syphilitic lymphadenopathy should be distinguished from lymphadenopathy caused by soft chancre and venereal lymphogranuloma.

3. The rash of secondary syphilis should be distinguished from pityriasis rosea, erythema polymorpha, tinea versicolor, psoriasis, and ringworm of the body. Genital warts should be distinguished from genital warts.

Syphilis complications

1. Syphilis pregnant women can infect the fetus, causing stillbirth, miscarriage, premature birth, and congenital syphilis in the baby, which seriously endangers the health of women and children.

2. Treponema pallidum invades the central nervous system and can cause meningeal vascular disease, spinal cord dysentery, and paralytic dementia. Invasion of the cardiovascular system can lead to aortic inflammation, aortic insufficiency, and aortic aneurysms. Severe cases can be fatal.

3. Treponema pallidum damages the bones, eyes, respiratory tract, digestive tract and other systems, causing tissue and organ damage, loss of function, and severe cases leading to disability or other adverse consequences. The prevalence of syphilis has severely affected society. The loss of labor due to illness has increased the social burden. Syphilis can also affect family stability.

Syphilis treatment

Treatment principle

Emphasize early diagnosis, early treatment, regular course of treatment, and sufficient dose. Clinical and laboratory follow-up is performed regularly after treatment. Sex partners must be investigated together. Early syphilis can be cured clinically and eliminate infectivity through thorough treatment. Advanced syphilis treatment can eliminate inflammation in the tissue, but the damaged tissue is difficult to repair.

Penicillin, such as water penicillin, procaine penicillin, benzathine penicillin, etc. is the drug of choice for different stages of syphilis. Those who are allergic to penicillin can choose tetracycline and erythromycin. Some patients may have Jihai reaction at the beginning of penicillin treatment, which can be prevented by starting with a small dose or using other drugs. The serum should be reviewed every 3 months in the first year after syphilis treatment, and every 6 months thereafter for a total of 3 years. Neurosyphilis and cardiovascular syphilis should be followed for life.

2. Early syphilis (including primary and secondary syphilis and early latent syphilis)

(1) Penicillin Therapy, benzathine penicillin G (long-acting cilin), intramuscular injection on both hips, once a week for a total of 2-3 times. Procaine penicillin G, intramuscular injection for 10 to 15 consecutive days, a total of 8 million u to 12 million u.

(2) Those who are allergic to penicillin Tetracycline hydrochloride, taken orally for 15 days. Doxycycline, even for 15 days.

3. Advanced syphilis (including tertiary skin, mucosal, skeletal syphilis, and late latent syphilis) and secondary syphilis

(1) Penicillin Penicillin G, once / week, intramuscularly, 3 times. Procaine penicillin G, intramuscular injection for 20 consecutive days. The treatment can be repeated once every 2 weeks.

(2) Those who are allergic to penicillin Tetracycline hydrochloride, taken orally for 30 days. Doxycycline for 30 days.

4. Neurosyphilis

Should be hospitalized, in order to avoid Jihai's reaction during the treatment, prednisone was administered orally once a day before penicillin injection for 3 consecutive days.

(1) Intravenous drip of penicillin G for 14 days.

(2) Intramuscular injection of procaine penicillin G and probenecid orally for 10 to 14 days.

After the above treatment, benzathine penicillin G was received once a week for 3 weeks.

5. Syphilis during pregnancy

Treatment is given according to the syphilis treatment plan for the corresponding disease period, and one course of treatment is applied in the first 3 months of pregnancy; one course of treatment is applied in the last 3 months of pregnancy. Patients who are allergic to penicillin should be treated with erythromycin, with early syphilis for 15 days, and secondary relapse and late syphilis for 30 days. The babies born should be treated with penicillin.

6. Fetal syphilis (congenital syphilis)

Early congenital syphilis (less than 2 years old) cerebrospinal fluid abnormalities: water agent penicillin G or procaine penicillin G treatment, the specific dose as prescribed by your doctor. Normal cerebrospinal fluid: benzathine penicillin G, one injection (divided into both gluteal muscles). If the cerebrospinal fluid is checked unconditionally, it can be treated according to the cerebrospinal fluid abnormality.

7. Syphilis treatment for pregnant women

(1) Married women with a history of syphilis must undergo a comprehensive syphilis examination before pregnancy. Women who have had an unclean sex life or have been infected with syphilis are advised to go to a regular hospital for a comprehensive syphilis test before planning to become pregnant. Married women who have completed syphilis treatment and whose symptoms of syphilis are not obvious should not be pregnant until the syphilis is cured.

(2) Syphilis examination and treatment during pregnancy: Serological examination of syphilis should be performed in the first 3 months and the end of pregnancy. If infection is found, syphilis should be treated regularly to reduce the chance of fetal syphilis.

8. Jihai response in syphilis treatment

Fever, headache, joint pain, nausea, vomiting, and exacerbation of syphilis may occur within a few hours after the first application of poison treatment. It is a Jihai reaction, and symptoms will usually be relieved within 24 hours. In order to prevent the occurrence of the Jihai reaction, penicillin can be gradually increased from a small dose to a normal amount. For neurosyphilis and cardiovascular syphilis, a short course of prednisone can be given before treatment, and divided into doses. 2 to 4 days after anti-syphilis treatment Disable. Corticosteroids can reduce the fever of the Jihai response, but its effect on local inflammatory responses is uncertain.

9. Diet Precautions

After syphilis, like other infectious diseases, you should eat fresh vitamin-rich vegetables and fruits, eat less greasy diet, avoid spicy food, quit smoking, alcohol, drink plenty of water, which is beneficial to the body's toxins. exclude.

Prognosis of syphilis

After treatment of syphilis, how to judge whether it is cured is usually judged by syphilis serological tests. RPR (Rapid Plasma Reactin Ring Card Test) and TPPA (Treponeema pallidum agglutination test) are commonly used in major hospitals. RPR is a non-specific syphilis serological test, often used to judge the efficacy. TPPA has high sensitivity and specificity in detecting specific Treponema pallidum antibodies in serum. Once the test is positive, whether it is treated or not, or the disease is active, it usually remains positive for life. Its titer change has nothing to do with syphilis activity, so it cannot be used as an index to evaluate the effect or determine recurrence and reinfection. Confirmation test.

For those diagnosed with syphilis, it is best to do quantitative RPR tests before treatment. Only when the titer changes between the two quantitative tests is more than 2 dilutions can the titer decrease be determined. After regular treatment of syphilis patients, the RPR is reviewed every three months, and the RPR is reviewed every six months after half a year. Follow-up is conducted for 2 to 3 years to observe and compare the current and previous RPR titer changes. After 3 to 6 months of treatment, the titer decreased more than 4 times, indicating that the treatment was effective. The titer continued to decline and even turned negative. If the results of three to four consecutive tests are negative, the patient can be considered to have clinically cured the syphilis.

After anti-syphilis treatment, the serum response of patients with syphilis generally has three possible changes:

1. Serum negative conversion.

2. Decreased serum titer does not change, or serum resistance.

3. It becomes positive after turning negative, or rises during continuous decline, indicating recurrence or reinfection.

Different stages of syphilis are treated with different drugs, and the negative response rate of serum may be different. Stage I and II syphilis are treated with any anti-syphilis drug, and the serum negative conversion rate is high, usually ranging from 70% to 95% within 1 to 2 years. After 12 months of regular anti-syphilis treatment of primary syphilis and 24 months of secondary syphilis, the serum response remains positive. It is clinically referred to as serum resistance or serum fixation. The cause may be related to the potential activity in the body. There are factors related to the disease, decreased immunity of the patient, insufficient dose of anti-plum treatment, or drug resistance, and there are no reasons found. For such patients, a comprehensive physical examination including cerebrospinal fluid examination and AIDS examination should be done to find possible causes and give corresponding treatment. If there are no special abnormalities, follow-up observations can be made regularly. Do not blindly give antibiotics for overtreatment.

Syphilis prevention

First of all, health education and publicity should be strengthened to avoid unsafe sex. Secondly, the following precautions and precautions should be taken.

1. Track the patient's sexual partners, find all sexual contacts of the patient, conduct preventive inspections, follow-up observations and perform necessary treatments. Sexual behavior is prohibited before cure.

2. Suspected patients should undergo preventive inspections and syphilis serum tests to detect patients early and treat them promptly.

3. For pregnant women suffering from syphilis, effective treatment should be given in time to prevent the infection of syphilis to the fetus. Unmarried people with syphilis are best cured before getting married.

4. If blood donation is needed, go to a regular blood collection point, and a comprehensive blood test is required before blood donation to prevent infection. If blood transfusion is needed, the blood transfusion unit needs to show a test certificate of the blood transfusion to prevent unnecessary trouble.

5. Patients with syphilis should pay attention to the combination of work and rest, carry out the necessary functional exercises, maintain a good attitude, and facilitate rehabilitation.

6. Pay attention to the details of life and prevent the infection of others: Early syphilis patients are more infectious. Although the infectivity of late syphilis gradually decreases, they must be carefully protected. Wash your underwear and towels separately, boil and sterilize, and take a bath without sharing the same pot with others. When hard chancre or vulvar or perianal genital warts occur, you can use Chinese herbal medicine decoction to clear the heat and detoxify, dehumidify and kill insects and wash the bath.

7. Patients with syphilis should not have sex before they are cured, and condoms must be used if they occur.