*3.4.3.1 Oculogenital infections*

Half of the approximately 20 million new sexually transmitted infections (STIs) diagnosed annually in the USA affect those aged 15–24 and both male and female STI rates are on the rise, with the majority of this increase occurring among adolescents [83]. It is estimated that one in four sexually active adolescent girls have a sexually transmitted infection, most commonly *C. trachomatis* (CT) and human papillomavirus (HPV) [84].

From a behavioral and biological point of view, adolescents are presumed to engage in high-risk sexual behavior, such as having multiple partners or not using a condom. And due to the biological factors, it is known that adolescent females are susceptible to sexually transmitted diseases due to cervical ectopy, and lower production of cervical mucous. Studies indicate that *C. trachomatis* infection is more prevalent in patients with cervical ectopy, which is more common in adolescents [85, 86]. In addition, most *C. trachomatis* infection is asymptomatic and adolescents are less likely

#### *Childhood Chlamydia Infections DOI: http://dx.doi.org/10.5772/intechopen.111712*

than adults to apply for sexual health services and have STD screening. Healthcare professionals usually do not feel confident about questioning adolescents and young adults about their sexual behaviors, assessing for STI risks, and screening for STIs. These factors contribute to creating an ongoing reservoir for infection and a lower chance of diagnosis and treatment.

Females infected with Chlamydia may develop cervicitis, urethritis, and proctitis, and males may exhibit urethritis, proctitis, and epididymitis as manifestations. In the majority of cases, heterosexual transmission accounts for a high rate. Since the majority of chlamydia infections, including non-genital infections, are asymptomatic, routine screening of at-risk populations is recommended for preventing transmission to sexual partners and preventing complications of untreated infections. A total of 82 Colombian women were followed for five years using serotyping and polymerase chain reaction (PCR) on cervical-scrap samples; it was stated that untreated, approximately 46% of infections were persistent at one year, 18% at two years, and 6% at four years, and manifesting symptoms were dysuria/pyuria syndrome, vaginal discharge, intermittent bleeding, and moderate abdominal pain [47]. Besides, they noticed that *C. trachomatis* can cause vaginitis in adolescence but not in adults; the squamous epithelium of the adult vagina is not vulnerable, and vaginal discharge is generally indicative of endocervical infection.

In women who do not get treatment, an ascending acute urogenital infection can cause severe, long-lasting pelvic inflammation. This can show up as endometritis, salpingitis, PID, chronic pelvic pain, etc., and it can damage the tubes, which can lead to infertility and ectopic pregnancy. The spectrum of PID associated with *C. trachomatis* infection extends from asymptomatic to a severe, acute disease characterized by perihepatitis and ascites (Fitz-Hugh–Curtis syndrome). It has been discovered that chlamydia screening reduces the incidence of PID [87].

In the USA, a national cross-sectional prospective cohort found that 95% of *C. trachomatis*-infected people had no symptoms. The most common symptoms among infected males were urethral discharge (3%) and dysuria (2%), while the most common symptoms among infected females were vaginal discharge (0.3%) and dysuria (4%). And seropositivity was only in 1% of vaginal discharges [88, 89]. A total of 38% of males reporting urethral discharge and 6% of females reporting dysuria were found to be positive for *C. trachomatis*.

Epididymitis, reactive arthritis (including Reiter syndrome), and transmission to females are the primary complications of chlamydial urethritis in men.

Although asymptomatic rectal and nasopharyngeal carriage of *C. trachomatis* can occur in both infants and adults, *C. trachomatis* is also reported as a cause of proctitis [90, 91].

Inclusion conjunctivitis is an extra-genital manifestation of this STD in both sexes that results from oto-inoculation of the eyes with contaminated genital secretion, typically as acute follicular conjunctivitis. The symptoms are usually a sensation of a foreign body in the eye. In most cases, the infection resolves without complications; however, if left untreated, it can persist for months and cause damage.

### *3.4.3.2 Lymphogranuloma Venereum*

LGV is a STI caused by the L1 to L3 *C. trachomatis* serovars.

The bubonic form of the disease is endemic to tropical and subtropical regions. Classically, LGV starts with a small papule or ulcer and days to weeks after

the primary lesion resolves spontaneously, unilateral inguinal lymphadenitis, and hemorrhagic proctitis develop. Systemic symptoms may accompany it, including fever, myalgia, and headache. Approximately one-third of inguinal buboes drain, and the rest involute slowly. Due to the persistence of chlamydia in anogenital tissues, a small proportion of patients with LGV develop a chronic inflammatory response with fibrosis, which can lead to chronic genital ulcers or fistulas, rectal strictures, or genital elephantiasis.

#### *3.4.4 Trachoma*

Trachoma remains one of the world's primary causes of blindness; approximately 30% of children in a holoendemic region are at risk of blindness due to severe trachoma [47]. Both pannus formation and progressive disease with scarring are thought to be the result of a long-term cycle of active infection and healing over the years.

In areas where trachoma is endemic, infections occur early in life and the disease remains active for several years. Poor hygiene and the presence of eye-seeking insects increase the likelihood of transmission. Inclusion conjunctivitis' characteristic chronic follicular conjunctivitis first appears, then the conjunctivae become more intensely inflamed, and finally, the tarsal conjunctiva fibrosis occurs. Trichiasis (turning of the eyelashes) frequently develops following extensive scarring of the inner surface of the lids. This causes additional corneal ulceration, fibrosis, opacification, and vision loss. Young adolescents with active trachoma can have *C. trachomatis* isolated from conjunctival scrapings and nasopharyngeal cultures.

#### **3.5 Diagnosis**

NAATs such as PCR assays are the guideline-recommended method for pathogen identification in acute *urethritis* [92]. First-catch urine or a urethral swab specimen can be used. NAATs also have more sensitivity and specificity than culture in nasopharyngeal and rectal infections both in males and females [93–96]. For *urogenital infections in females*, NAATs are the most sensitive tests as well and are recommended for laboratory diagnosis.

Both cell culture and nonculture assays are sensitive and specific diagnostic techniques such as direct fluorescent antibody tests (DFA) and NAAT, in the diagnosis of *neonatal chlamydial conjunctivitis* [97, 98]. Because eye discharge alone is not sufficient, conjunctival cells are required, and the specimen should be obtained from the everted eyelid using a dacron-tipped swab.

For *chlamydial infant pneumonia*, cell culture is the definitive standard diagnostic test. Specimens collected from the posterior nasopharynx are recommended or tracheal aspirates and lung biopsy specimens if collected. Chlamydia culture in tissue culture is a sensitive and specific method for detecting neonatal chlamydial infections; however, it is time-consuming and costly and has been largely replaced by NAATs. DFA or NAATs can be used in the same specimens but have lower sensitivity and specificity than culture. Microimmunofluorescent (MIF) serum titer of *C trachomatis*-specific immunoglobulin Ig M > 1:32 is diagnostic.

Only molecular testing that is specific to LGV can provide a definitive diagnosis of LGV (for example, PCR-based genotyping).

Trachoma of the eye is typically diagnosed clinically in countries where the disease is endemic.

When concerning possible sexual child abuse, it is preferred the child be referred for complete evaluation and management to an experienced/specialized pediatrician, clinic, or child advocacy center, with a prompt examination for other SDIs as well. If sexual abuse is suspected, appropriate social service and law enforcement agencies must be contacted to evaluate the situation, ensure the child or adolescent's safety, and provide appropriate counseling.

#### **3.6 Treatment**

Because the elementary body is metabolically inactive, the treatment should target the intracellular form of the organism and have strong intracellular penetration. And, given CT's 36–48-hour intracellular formation cycle, a long therapeutic duration or a long half-life antibiotic should be chosen to assure appropriate levels of the antibiotic.

To prevent *C. trachomatis* infection-related complications, decrease the risk of transmission to sex partners and newborns in pregnant individuals, resolve the symptoms, eradicate the microorganism, and prevent re-infection, screening and treating adolescents and young people are recommended. After starting doxycycline or azithromycin, clinical improvement is achieved in 83–86% of symptomatic patients with cervicitis and urethritis [98]. By the way, because most of the patients are asymptomatic, microbial eradication should be targeted.

*Inclusion conjunctivitis or Pneumonia of infancy*: Erythromycin (50 mg/kg/day in 4 doses) for 10–14 days or Azithromycin (10 mg/kg/day) for 5 days [33]. Empiric antibiotic treatment is recommended for neonatal pneumonia till to diagnostic results are available, but not for conjunctivitis [98].

*Genital infections in adolescents*: CT is shown to be susceptible to tetracyclines, macrolides, and some of fluoroquinolones [99]. Although amoxicillin is effective, penicillins are accused of easing the *in vitro* persistence of the microorganism [100].

If laboratory diagnosis is not possible, symptomatic patients with cervicitis, urethritis, epidydymithis, or acute prostatitis who have had recent known or possible sexual exposure can be offered empiric treatment for CT.

Doxycycline is given as 100 mg twice daily for seven days, or single-dose 1 gram azithromycin is recommended by the CDC in the treatment of genital chlamydia infections [83].

Although doxycycline seems microbiologically more effective than azitromycin, especially in rectal infections [101–103], azitromycin has the advantage of better adherence to treatment with a single dose. Levofloxacin and ofloxacin are the alternative antibiotics recommended.
