Chlamydia: Method of Transmission, Pathogenesis, and Diagnosis - Research Paper Example

Chlamydia Etiological Agent Chlamydia is a bacterial infection caused by Chlamydia trachomatis. The Genus is Chlamydia while the species name is C. trachomatis. According to the CDC (2014a), Chlamydia is a nationally notifiable disease in the United States. In America, the disease infects about 2.8 million individuals annually, and it is characterized by a high proportion of asymptomatic cases. Globally, Chlamydia is the most commonly reported sexually transmitted disease (Malik, Hakim, Shukla, & Rizvi, 2006). Most of the infections occur in sexually active adults and young adults. In addition, it affects both men and women. Additionally, about 30 to 50 percent of the women in the United States have been exposed to the bacterium at one point in their life. Additionally, Chlamydia ascends to the upper genital tract if left untreated in about 40 percent of the cases. As a result, C. trachomatis is known to be one of the major causes of acquired infertility. Generally, due to the high prevalence and adverse complication of untreated infections Chlamydia remains a major public health problem in industrialized countries (Dean, et al., 2009). Method of Transmission As aforementioned, Chlamydia is transmitted from one individual to another through oral and sexual contact. Penetrative sexual intercourse is the primary mode of transmission. Chlamydia is transmitted through the vagina, anus, and oral sexual intercourse with an disease-ridden partner (Malhotra, Sood, Mukherjee, Muralidhar, & Bala, 2013). Infected individuals are the reservoirs of the infection. According to Breguet (2006), Mother to Child Transmission (MCT) can occur during vaginal delivery. In addition, conjunctivitis can occur on the occasion that a person touches his or her eyes with infected hands. The infections occur in the urethra, cervix, throat, rectum, eyes, throat, penis, and cervix (Breguet, 2006). Pathogenesis According to the CDC (2007), a quarter of the females infected and half of the males do not present with any symptoms. In this regard, it is referred to as the ‘silent’ disease. However, in the population that presents with symptoms, they usually occur within 1 to 3 weeks after infection. Additionally, the symptoms tend to present differently in both men and women. The urethra and the cervix are the major organs affected in women. After an infection, women present with symptoms such as abnormal vaginal discharge and pain when passing urine. An infection of the cervix and fallopian tubes is characterized by symptoms such as pain during copulation, abnormal vaginal bleeding, abdominal pain, vomiting, and fever (CDC, 2007). In the males, the symptoms include abnormal discharge from the penis, and pain when passing urine. In some cases, patients present with swollen testicles. In the case of rectal infection, patients present with bleeding, abnormal discharge, and pain. According to Darville and Hiltke (2010), the pathogenic mechanism of C. trachomatis remains vague. However, the available research data indicate that an infection with the bacteria results in the inflammation of the host epithelial cells after the production of immunogenic antigens. The human CD4 Th1-interferon-g-producing cells play a major role in protecting individuals from an infection. Moreover, the infection mediates both the cell and humoral mediated immune responses in the hosts. The host’s body also produces chemokines and cytokines after the bacteria causes an inflammation of the epithelial cells (Malhotra, Sood, Mukherjee, Muralidhar, & Bala, 2013). After the release, the cytokines act on the neutrophils, T-lymphocytes, and monocytes. The process leads to the activation, vasodilation, and enhanced permeability of the aforementioned cells. The process also activates the production of cytokines from other cells. Neutrophils play an important role in inhibiting the spread of the bacteria beyond the genitalia. IgA also plays a vital role in the preventing the penetration of the bacteria to other organs. According to Darville and Hiltke (2010), a single acute infection with the bacteria does not result in grave consequences. However, recurrent infections with the organisms cause persistence presence of the bacteria in the cells of the host resulting in chronic infections. Diagnosis Either the diagnosis of the infection can be clinical or laboratory based. A clinical diagnosis is based on the symptoms mentioned. Various tests are conducted in the laboratory to determine the presence of the bacteria in the human body. Cell culture is the gold standard in the diagnosis of Chlamydia (Malhotra, Sood, Mukherjee, Muralidhar, & Bala, 2013). In this technique, an embryonated hen’s egg is used to enhance the bacterial growth and this is due to the obligate intracellular characteristic of the pathogen. The Enhanced Eagles Minimal Essential Medium (EMEM) is used to culture the pathogen and it is incubated for two to three days. However, this technique is labor intensive and expensive. The second laboratory diagnosis technique is the Direct Fluorescent Test (DFA), which involves the identification of Chlamydia antibodies. It is a rapid test and feasible in many settings. Enzyme Linked Immunosorbant Assay (ELISA) test is also used in the diagnosis (Malhotra, Sood, Mukherjee, Muralidhar, & Bala, 2013). The test is used in the identification of trachomatis antigen in human serum. Commercial kits are used for this test. However, the ELISA has poor sensitivity compared to cell culture. Cytology is another cost effective test in the diagnosis of Chlamydia. Technical and microscopic methods are used to assess the results of the clinical specimen in cytology. Molecular methods through PCR can also be employed in the laboratory diagnosis. Other techniques include; Leukocyte enterase test, rapid point of care test, and serology testing (Malhotra, Sood, Mukherjee, Muralidhar, & Bala, 2013). Treatment The CDC (2007) indicates that the treatment of a Chlamydia infection is dependent on the site and complexity of infection. Uncomplicated infections are easier to treat and oral azithromycin (1 dose daily), or oral doxycycline (two doses daily) are used to clear the bacterium. The treatments should be taken for seven days. Other recommended regimens include erythromycin and ofloxacin (CDC, 2007). Azithromycin or amoxicillin doses are recommended for pregnant women. All partners should be screened and treated for the infection. Furthermore, they should abstain from sexual intercourse until the infection is cleared. Prevention and Control Methods Previous attempts to develop protective vaccines have been unsuccessful (Malhotra, Sood, Mukherjee, Muralidhar, & Bala, 2013). Based on the guidelines of the CDC, prevention and control methods can be either primary or secondary. Primary prevention involves community health education on the impacts of risky sexual behavior and prevention of the acquisition of the pathogen (CDC, 2014b). Additionally, educational health programmes should be introduced in schools to educate the adolescents on safe sexual practices. Secondary prevention and control methods involve screening women for the asymptomatic disease in an effort to prevent further spread. Doctors encourage routine screening of the infection among the sexually active females below 25 years. In addition, expectant females should be investigated for Chlamydia. However, screening is not recommended for men (CDC, 2014b). Recent Outbreaks In reference to the Morbidity and Mortality Weekly Report (MMWR) released on September 26 2014, Chlamydia infections in the population are monitored through the National Health and Nutrition Examination Survey (NHANES) (CDC, 2014b). Based on data collected from 2000 to 2012, the prevalence of the disease in individuals aged 14-39 years was 1.7 percent (C. I 1.4%-2.0%) (CDC, 2014b). The prevalence in males was 1.4 percent, while in females 2 percent. Additionally, with reference to the infection, variations were reported on the race and ethnicity. Non-Hispanic Blacks were reported to have to the highest prevalence in the entire population. The proportion of females aged 14 to 24 years with Chlamydia was reported to be 4.7 percent (CDC, 2014b). Graphics Figure 1: Gender differences in the prevalence of Chlamydia in the United States References Darville, T., & Hiltke, T. J. (2010). Pathogenesis of Genital Tract Disease Due to Chlamydia trachomatis. The Journal of Infectious Diseases, 201 (S2), S114–S125. Breguet, A. (2006). Chlamydia. New York: Rosen Publishing Group. CDC. (2007). Chlamydia. Atlanta, Georgia: CDC. CDC. (2014a). Prevalence of Chlamydia trachomatis genital infection among persons-MMWR. Atlanta Georgia: Centers for Disease Control and Infection. CDC. (2014b). Prevalence of Chlamydia trachomatis genital infection among persons aged 14–39 years-United States, 2007–2012. Retrieved from: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6338a3.htm Dean, D., Bruno, W. J., Wan, R., Gomes, J. P., Devignot, S., Mehari, T., Spratt, B. G. (2009). Predicting phenotype and emerging strains among Chlamydia trachomatis infections. Emerging Infectious Diseases, 15 (9), 1385-1394. Malhotra, M., Sood, S., Mukherjee, A., Muralidhar, S., & Bala, M. (2013). Genital Chlamydia trachomatis: An update. Indian Journal of Medical Research, 138 (3), 303–316. Malik, A., Hakim, J. S., Shukla, I., & Rizvi, M. (2006). Chlamydia trachomatis infection & female infertility. Indian Journal of Medical Research, 123 (44), 770-775. Read More