Epidemiology of Tuberculosis

Tuberculosis and Epidemiology

The epidemiology of TB in a highly populated community in a suburban area in South Africa

Tuberculosis (TB) remains a chief cause of mortality and morbidity across the world (World Health Organization, 2009). In order to establish effectual intervention policies for the control of TB, it is essential to comprehend TB transmission in settings of high burden. In South Africa, the HIV and TB prevalence rates are relatively high with the prevalence rate being above 500 people per 100, 000 population (World Health Organization, 2011). Although there have been topical studies to assess TB infection among young children (Shanaube et al. 2009), there are hardly any data evaluating TB infection in adolescents and older children in communities that have high TB and human immunodeficiency virus problems (Wood et al. 2010). There have been routine uses of tuberculin skin test surveys to test for TB illness in communities, although there are only a few data from surveys using the tuberculin skin test from nations in which both (HIV) infection and TB are prevalent. The research shall be on school-going children aged 5 -- 17 years in a neighborhood that is experiencing an increase in the prevalence of HIV and TB. The school is a government school located within the community where there is a high prevalence of HIV. The hypothesis of this study is that there are high rates of TB infections among adolescents and children in a neighborhood with a high prevalence of HIV among adults.

The research questions for this research shall be:

1. What is the HIV and TB infection prevalence in the community?

2. What is the rate of TB infection among children in the community?

3. What is the relationship between HIV infection prevalence among adults and the rate of infection of TB among children and adults?

Section 2: Research Methods

The researcher will perform Tuberculin skin test survey on a population sample of children who attend school in the community under study, which is comprised of predominantly Xhosa-speaking people who live in a high-density and very poor residential area. The research will involve a cross-sectional survey in 2 stages among the school children who are enrolled and attending the local public primary school. Children will be eligible if they are a resident of the community and are enrolled at the local school. Children in the grades 5-7 will be enrolled in June 2013 and those in grades 2 -- 4 will be enrolled in December 2007. The researchers will seek parental consent and assent for participants who are ?6 years of age will be obtained before enrollment. The researcher will carry out the survey on the school grounds and will collect basic demographic information for each participant. However, the researcher will carry out a TST for all participants regardless of their BCG scar status. A trained nurse will administer polysorbate 80, with the standard of 2 TU of purified protein derivative RT23 that the World Health Organization recommends, intradermally on the left forearm's volar surface. Three days after the inoculation, a trained reader will measure the size of the upshot to the tuberculin. The researcher will note the absence or presence of a reaction, and, where present; the research will involve the measurement of the size of the induration along the perpendicular axis by means of standard calipers.

All the children who have a TST reaction induration of ?10 mm will be recalled for examination for active TB, and those children who have symptoms or signs of active TB will be referred to the neighboring clinic for further management. The researcher will analyze data using STATA, version 9.0. The researcher will calculate the results that the researcher will receive as the mean of the TST reaction induration's 2 diameters: a positive reaction will be defined at the cutoff points of 10-mm and 17.4-mm in discrete analyses. The 10-mm cutoff will be on the basis of the guiding principles for infection in clinical settings, and the 17.4-mm cutoff was determined as the mean induration size but after excluding all individuals who are nonreactive (South African Department of Health, 2004). The Annual Risk of Tuberculosis Infection (ARTI) will be as follows:

1-(1-prevalence) 1/mean age+0.5

The research will include the use of age, in full years, of the patient at their closest birthday thereby a need to add 0.5 to the mean age in calculating the ARTI (South African Department of Health, 2004). The researcher will divide the cohort into clusters of participants in ages of 5 -- 9 years, 10 -- 13 years and 13 -- 17 years, and will calculate ARTI and prevalence overall and for every age group. The researcher will also use Wilcoxon rank-sum tests for comparing of TST results between the various age groups. The use of a x2 test for trend will be for examining for a trend between ARTI and age, as well as for shifts in TB notification rates in a period over the 5-year period. All statistical tests will be 2-sided, with ?=0.05

The researcher will obtain the number of notified TB cases in adolescents and children from the TB register at the community's TB clinic. The TB prevalence rates will be calculated employing the Southern African National Census of 1996 and the house-to-house census that the Desmond Tutu HIV Centre conducted in 2003, 2004, and 2006. In calculating the ratios of prevalence of TB and occurrence of new infections from TB, the researcher will use the ARTI and the TB incidence and prevalence data that are already published with regard to this community (Lawn et al., 2006).

Section 3: The Intervention

Prevention programs will need conceptual frameworks in order to develop interventions and select the most efficient policy. In South Africa, there is a policy that all children should receive a BCG vaccination. Although this policy has been in place since 1960, it is quite common knowledge that only a few people have had the vaccination, although the vaccination may be valuable. In addition, South Africa has other TB control strategies such as the treatment of active disease, case finding, and treatment of latent TB infection (Wood et al., 2011). Despite this, rate of TB infection in South Africa has gone high over the past two decades, the country now has the highest TB burdens in the entire world. The rates of TB infection among children and adolescents are expected to be so high especially in areas that have prevalence rates of HIV and TB in adults (Wood et al., 2011). This is an indication that these strategies to control TB have become unsuccessful, implying a need to improve these strategies and reinforce the existing ones, where possible.

First, there is a need to target reducing the high force of TB infection, particularly in high-density townships. It is paramount to understand that the benefits of enhanced case finding will depend on the existing epidemiology of TB transmission (Zhang, Jiang, and Wang, 2009). Detecting a case of TB, especially in a locale with a 10 will, in addition averts up to 10, secondary cases. The advantages of earlier and increased case finding on the spread of TB should be amplified in significantly high-transmission areas. Lessening the TB infection rates is elementary in attaining the long-term goal of TB control of a stable regression of the disease in succeeding generations (Cobelens et al., 2012). An improved and intensified case-finding programs, as part of the use of community-based interventions in historical TB control measures should be re-explored, in the view of the supplementary advantages increment for reducing transmission.

There is a need to decrease the time of diagnosis by use of advanced technologies such as molecular diagnostic technologies (World Health Organization, 2006; Shimao, 2005). This is because lessening of the infectiousness period has an impact on the prevalence of the infectious TB. This time of infectiousness is a result of delays, which include diagnostic delays, health-seeking behavior and health systems delays in starting effectual chemotherapy. There is a need for an intensified case finding to increase awareness of the usual symptoms of the TB infection. There is also a need for enhanced health systems effectiveness that can further lessen the time to begin effective TB treatment.

Investing in intensive campaigns to lobby for the public's participation in BCG vaccination will be a step forward in encouraging the community members to take their children for vaccination. This will work to reduce the number of TB infections among adolescents and children. There is also a necessity to implement age-specific interventions to interrupt the transmission of TB to infants, young children, school going children and adolescents, and adults. A decrease in TB infection rates among children, and a stable decrease in the number of the children who are latently infected would indicate a decrease in the number of…