**4. Trichomoniasis**

*Trichomonas vaginalis* infects the urogenital tract of men and women, causing trichomoniasis. *Trichomonas vaginalis* is a member of the Phylum Zoomastigina, Class Parabasalia, Order Trichomonadida, and Family Trichomonadidae. *Trichomonas vaginalis* has only one life stage, trophozoites, which display various shapes including pyriform, ameboid, ellipsoidal, ovoidal, and spherical. The organisms measure between 10 – 30 microns. The organism possesses four anterior flagella and a fifth flagellum located posteriorly along the undulating membrane. These flagella of the organism yield the characteristic quivering motion of *T. vaginalis*.

#### **4.1 Epidemiology**

Trichomoniasis is the most common, curable, non-viral sexually transmitted infection worldwide. An estimated 174 million new cases of trichomoniasis occur worldwide each year. The incidence of *Trichomonas vaginalis* infection varies in different countries throughout the world. Incidence in Asian countries varies from 0.7% in rural China to 15.1% in sex workers in Indonesia. In South America, studies report incidence ranging from 4-9%. In Brazil prevalence is thought to have a range of 20 up to 40%. Incidence in African countries ranges from 2-20%. The incidence of trichomoniasis is higher in sexually active women over 25 years of age than in younger women.

#### **4.2 Clinical manifestations**

462 Current Topics in Tropical Medicine

pathogens. The recommended syndromic treatment is a single dose therapy for gonorrhea, plus doxycyline, 100 mg orally twice daily, or tetracycline, 500 mg orally 4 times daily for 14 days, plus metronidazole, 400-500 mg orally twice daily for 14 days. Patients who do not respond to therapy within three days should be referred for a more complete diagnostic

Infants with neonatal conjunctivitis (ophthalmia neonatorum) present with eyes that are red, swollen and accompanied by discharge ("sticky eyes"). *Chlamydia trachomatis* and *N. gonorrhoeae* are the most significant pathogens which cause ophthalmia neonatorum in developing countries although infections from *Staphylococcus aureus*, *Streptococcus pneumoniae*, *Haemophilus* spp., and *Pseudomonas* spp. occur. The oropharynx, urogenital tract, and rectum of neonates may also be affected in *Chlamydia trachomatis* or *N. gonorrhoeae* infection. *Neisseria* conjunctivitis develops within a few days of birth whereas *C. trachomatis* conjunctivitis develops slower, 5-14 days after birth. Neonatal conjunctivitis caused by *N. gonorrhoeae* can lead to blindness when untreated. Coverage should be provided for both of these STIs in settings where definitive diagnosis is not possible, especially where there is evidence of a maternal STI. Treatment should include a single dose therapy for gonorrhea and multiple dose therapy for chlamydia. For gonorrhea a single intramuscular injection of ceftriaxone, 50 mg/kg to a maximum of 125 mg total, should be administered. If ceftriaxone is unavailable, single injections of kanamycin or spectinomycin at 25 mg/kg to a maximum dose of 75 mg total may be used. For chlamydia treatment, erythromycin syrup, 50 mg/kg per day orally, in 4 divided doses for 14 days or trimethoprim, 40 mg with sulfamethoxazole, 200 mg orally twice daily for 14 days are recommended. Gonococcal ophthalmia neonatorum is preventable if a 1% silver nitrate solution or 1% tetracycline

*Trichomonas vaginalis* infects the urogenital tract of men and women, causing trichomoniasis. *Trichomonas vaginalis* is a member of the Phylum Zoomastigina, Class Parabasalia, Order Trichomonadida, and Family Trichomonadidae. *Trichomonas vaginalis* has only one life stage, trophozoites, which display various shapes including pyriform, ameboid, ellipsoidal, ovoidal, and spherical. The organisms measure between 10 – 30 microns. The organism possesses four anterior flagella and a fifth flagellum located posteriorly along the undulating membrane. These flagella of the organism yield the characteristic quivering

Trichomoniasis is the most common, curable, non-viral sexually transmitted infection worldwide. An estimated 174 million new cases of trichomoniasis occur worldwide each year. The incidence of *Trichomonas vaginalis* infection varies in different countries throughout the world. Incidence in Asian countries varies from 0.7% in rural China to 15.1% in sex workers in Indonesia. In South America, studies report incidence ranging from 4-9%. In Brazil prevalence is thought to have a range of 20 up to 40%. Incidence in African countries ranges from 2-20%. The incidence of trichomoniasis is higher in sexually active

evaluation.

**3.7 Neonatal conjunctivitis** 

**4. Trichomoniasis** 

motion of *T. vaginalis*.

**4.1 Epidemiology** 

ointment is applied at birth as a prophylactic measure.

women over 25 years of age than in younger women.

The actual number of new or existing cases of trichomoniasis is not known with complete surety because trichomoniasis is not a reportable disease and because of the significant number of asymptomatic cases. Trichomoniasis is usually asymptomatic in men, although sometimes it can cause non-gonococcal, non-chlamydial urethritis, epididymitis, and prostatitis. Clinical trichomoniasis in women ranges from asymptomatic carriers to flagrant vaginitis. Women have symptomatic disease more often than men. One third of asymptomatic woman will become symptomatic within 6 months of the onset of infection. Symptoms can include a vaginal discharge, vulvovaginal irritation and itching, painful urination or intercourse, foul odor, and lower abdominal pain. The presence or absence and severity of these symptoms determine whether the infection is classified as acute, chronic, or asymptomatic.

#### **4.3 Health sequelae**

Trichomoniasis is associated with a higher risk for other infectious diseases and adverse pregnancy outcomes such as preterm birth, premature rupture of placental membranes, and low birth weight infants. One study has also found an association between *T. vaginalis infection* in pregnancy and mental retardation in children. *Trichomonas vaginalis* infection is associated with pelvic inflammatory disease, especially PID leading to sterility. Trichomoniasis is significantly associated with HSV infection. *Trichomonas vaginalis* infection also increases the risk of human immunodeficiency virus (HIV) acquisition and the Centers for Disease Control and Prevention (CDC) estimates that as much as 20% of HIV transmission in the African American population in the United States may be attributable to *T. vaginalis* infection. *Trichomonas vaginalis* infection also increases the risk of cervical neoplasia and prostate cancer. Exposure to *T. vaginalis* results in a 2-fold increase in the risk of diagnosis of extraprostatic prostate cancer and a 3-fold increase in the risk of cancer that led to cancer-specific death. Thus, although trichomoniasis itself is a curable disease, *T. vaginalis* infection may indirectly be a life threatening disease.

#### **4.4 Diagnosis**

Because of the high prevalence of trichomoniasis, any woman seeking medical care for vaginal discharge should be tested for *T. vaginalis* infection. Trichomoniasis is traditionally diagnosed microscopically (wet mount) by observing mobile protozoa in vaginal secretions, cervical samples, or from urethral or prostatic swabs. However, this method has a relatively low sensitivity and requires immediate evaluation of a wet preparation slide for optimal results. The low sensitivity of this diagnostic method leads to under-diagnosis. The current gold standard for diagnosis of trichomoniasis is culture in Diamonds media and is widely used. Rapid antigen based point-of-care tests and nucleic acid based diagnostic tools are also available. Both of these techniques have high sensitivity and specificity. Papanicolaou (Pap) smear allows for direct visualization in saline prep and can be performed within 10-20 minutes of sample collection but is not widely used. The Whiff test can be performed by mixing vaginal secretions with 10% potassium hydroxide (KOH) to yield a strong fishy odor. This test has a poor specificity due to the fact that bacterial vaginosis can yield a similar result. All of the above mentioned diagnostic methods are applicable for diagnosis in women. In men, culture testing of urethral swabs, urine, or semen and the nucleic acid amplification tests are more sensitive diagnostic tools.

Sexually Transmitted Infections in the Tropics 465

abnormal bleeding, and dysparenia but many women show no signs of infection. Untreated PID can result in chronic pelvic pain, tubal infertility in 10-20% of women, and occasionally potentially fatal ectopic pregnancy. Repeated infections increase the risk of adverse sequelae in both men and women. In rare cases persons with genital chlamydial infection can develop Reiter's syndrome, a triad of reactive arthritis accompanied by conjunctivitis and urethritis. Chlamydial infection, even asymptomatic disease, increases the risk of adverse pregnancy outcomes: premature rupture of membranes, preterm delivery and low birth weight. *Chlamydia* can easily pass to neonates during childbirth causing neonatal conjunctivitis and afebrile pneumonia in approximately 60% of those with infected mothers. The high levels of *Chlamydia* infection worldwide mean that there is substantial neonatal

The *Chlamydia* serotypes which cause LGV are more virulent and more invasive than other chlamydial serotypes. The initial stage is a painless genital papule which heals rapidly and may be unrecognized. The organism then disseminates to regional lymph nodes, usually the inguinal nodes, where they replicate within macrophages and elicit a systemic response. This produces a painful inguinal lymphadenopathy, usually unilateral, by 2-6 weeks after the primary lesion often accompanied by fever, headache, and arthralgias. Rectal infection with LGV is characterized by a severe febrile proctocolitis, mimicking inflammatory bowel disease, with painful defecation, tenesmus, and less commonly a bloody mucopurulent discharge. Untreated LGV results in chronic inflammation with late fibrotic complications such as fistulas of the penis, urethra, and rectum, strictures, and genital lymphoedema and

Empirical evidence of *Chlamydia* infection is based on clinical presentation. The presence of greater than 10 polymorphonuclear leukocytes (PMNs) per 1000X field in vaginal discharge or 5 PMNs/field in urethral discharge is indicative of the cervicitis or urethritis characteristic of *Chlamydia* infection. There are currently no widely available point-of-care tests for *Chlamydia* infections. Most *Chlamydia* infections are detected through screening programs based on nucleic acid amplification testing (NAAT), antigen detection by ELISA, and DNA hybridization. Screening is useful for identifying asymptomatic infected individuals and in confirming symptomatic infections, but the delay in obtaining results means that initial diagnosis will be primarily based on clinical presentation. Traditional diagnostic techniques used for bacterial infections, culture and Gram stain, are of limited value for chlamydial infections. *Chlamydia* is an intracellular pathogen that requires tissue culture to propagate and so this approach is infrequently used even in developed countries. The unique cell wall structure of Chlamydia makes it very difficult to stain, although it is considered Gram negative. Direct fluorescent antibody staining can identify *Chlamydia* in clinical specimens but is not widely available. Where testing is available, all sexually active young adults under 25 years should be screened for *Chlamydia*. All pregnant women should

The recommended regimen for treatment of *Chlamydia* infection is azithromycin, 1 g orally in a single dose, or doxycycline, 100 mg orally twice daily for 7 days. Alternative 7 day regimens are 500 mg erythromycin base orally four times a day, 500 mg levofloxacin orally once daily, or 300 mg ofloxacin orally twice daily. The frequency of *Chlamydia* and

morbidity from perinatally transmitted chlamydial infection.

elephantiasis.

**5.3 Diagnosis** 

be screened for *Chlamydia* as well.

**5.4 Treatment** 
