Prevalence of HIV infection and risk factors of tuberculin infection among household contacts in an hiv epidemic area: Chiang Rai Province, Thailand

During the course of the HIV epidemic in Chiang Rai Province in Northern Thailand, incidence of tuberculosis also sharply increased. Up to the year 2002, there were no specific interventions for the prevention and control of TB infection among the household contacts of an infected person. The study aimed to identify prevalence of HIV infection and risk factors of tuberculosis infection among household contacts.
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Prevalence of HIV infection and risk factors of tuberculin infection among household contacts in an hiv epidemic area: Chiang Rai Province, Thailand JOURNAL OF SCIENCE, Hue University, N0 61, 2010 PREVALENCE OF HIV INFECTION AND RISK FACTORS OF TUBERCULIN INFECTION AMONG HOUSEHOLD CONTACTS IN AN HIV EPIDEMIC AREA: CHIANG RAI PROVINCE, THAILAND Pornnapa Suggaravetsiri Khon Kaen University, Thailand Juthatip Putthasorn Chiang Rai Prachanukraow Hospital, Chiang Rai Province, Thailand SUMMARY During the course of the HIV epidemic in Chiang Rai Province in Northern Thailand, incidence of tuberculosis also sharply increased. Up to the year 2002, there were no specific interventions for the prevention and control of TB infection among the household contacts of an infected person. The study aimed to identify prevalence of HIV infection and risk factors of tuberculosis infection among household contacts. Methodology: A cross-sectional analytic study was conducted among household contacts of TB cases between January 2001 and January 2002. We collected data using structured interviews, physical examinations, tuberculin skin test (TST), mumps skin test and pre-test and post-test counseling for HIV testing. Results: The prevalence of positive tuberculin skin test among 1,211 household contacts was 57.55% and the HIV positive rate among household contacts was 7.74% (72 out of 930 contacts who did agree to HIV testing). Based on the variables entered into the model, gender, age, HIV status, caregivers of TB patients and living in the same room as the infected patient were significantly related to TB infection. However, the presence of a BCG scar was not significantly associated with TB infection. Conclusion: TB screening every 6 months should be provided to household members and children who had contacts with HIV positive individuals and the introduction of anti TB prophylaxis should be provided to HIV infected persons. Keywords: Tuberculosis, Households, Risk factors, HIV, Thailand 1. Introduction Tuberculosis (TB) and Human immune deficiency virus (HIV) are currently the major leading causes of death worldwide among infectious diseases. It is estimated that TB kills more than two million people each year. This problem is further aggravated by the alarming spread of HIV and the emergence of drug resistance. According to WHO estimates there were 8.8 million new case of TB in 2003 (140/100,000) of which 3.9 million (62/100,000) were positives smear and 674,000 (11/100,000) were infected with 403 HIV. Annually 5% to 15% of HIV- positive individuals develop TB and at least onethird of the world population, that is about 1.9 billion people are infected with TB. Within Chiang Rai province in Northern Thailand, 1990-1998 data revealed that the proportions of TB cases attributable to HIV was 72% among males- and 66% among female patients. The TB notifications increased from 40/100,000 population in 1990 to 144/ 100,000 population in 2002, which amounted to a three- fold increase in TB. This was mostly attributable to HIV. Obviously the problem of TB/HIV is an issue of critical importance, and challenging for investigation and control. Several studies were conducted to explored risk factors among TB patients, household members, and health care workers. However, most of them investigated the risk factors relating to the development of TB rather than its source of infection. This study aimed to identify the risk factors of TB infection among household contacts in a HIV epidemic area, Chiang Rai province, Thailand. 2. Methodology A cross- sectional study was carried out between January 2001 and January 2002. Three hospitals located in the epidemic area of Chiang Rai Province, Chiangrai Prachanukroa, Phan and MaeJan, were the study sites. Tuberculosis index cases (the first suspected case in each household) were diagnosed by chest radiography (CXR) and tested for acid-fast bacilli (AFB) in sputum. TB index cases and the household of each TB index case were visited by a researcher assistant. Household contacts were defined as members of an extended family of the index case who lived in the same house as the TB index case. Specific information about TB infection from the household contacts was collected by their response to a list of typical clinical symptoms of TB. Physical examination, mumps skin test and a tuberculin skin test (TST) were performed at the hospital or at home by well trained nurses. Indurative diameters of mumps skin test and the TST were measured within 48 to 72 hours. An indurative diameter of ≥ 10 mm of TST was considered to be a positive test (TB infection). Double data entry by using the software of Epi-info Version 6.02 (Atlanta, USA) was done to validate the data. The data file then was transferred to STATA 7.0 (Texas, USA) for statistical analysis to calculate the proportion of infection among household contacts and examine the effects of different factors related to ...