A STUDY ON THE INFLUENCE OF HIV INFECTION IN PULMONARY TUBERCULOSIS PATIENTS ON THE SE CONDARY TRANSMISSION OF PLJLMONARY TUBERCULOSIS TO HOUSEHOLD CONTACTS
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Date
2001
Authors
WAN MOHD ZAHIRUDDIN, WAN MOHAMMAD
Journal Title
Journal ISSN
Volume Title
Publisher
Pusat Pengajian Sains Perubatan Universiti Sains Malaysia
Abstract
Introduction: The Human Immunodefiency Virus (HIV) epidemic has had a profound
influence on the transmission of tuberculosis (TB). The potential for HIV -associated TB
cases to transmit M.tuberculosis and to produce a secondary increase in TB morbidity is
unknown. Objectives: To compare the prevalence of M.tuberculosis infection among
household contacts of HIV-positive and HIV-negative pulmonary TB (PTB) patients, and to
identify potential variables that associated with the transmission. Materials and Methods:
A cross-sectional study was carried out to review records of tuberculin (Mantoux) tests
administered during routine contact investigations at the Chest Clinic, Kota Bharu Hospital,
Kelantan from 1999 through 2000. HIV status of patients was based on the result of ELISA
tests while information on household contacts were recorded during house visit. Results:
One hundred and sixty eight contacts to 67 HIV -negative patients and 62 contacts to 22 cases
of HIV -positive PTB patients were included. Thirty-two percents (20/62) of contacts of HIVpositive
PTB had a positive tuberculin compared with 49.4 % (83/168) of contacts to HIVnegative
patients (crude Odds Ratio (OR) = 0.48 95% Confidence Interval (el) 0.26 - 0.90, p
= O. 020). HIV -infected PTB patients in this study had a less severe form of pulmonary
lesion without cavitations. The difference in tuberculin response among the household
contacts of each group was still significant after performing multivariate logistic regression
analysis to adjust for the severity of PTB and other potential variables associated with
infectiousness of TB (adjusted OR = 0.43, 95% CI 0.18 - 0.95 P = 0.04). Adult contacts,
crowding of house, longer duration of stay with index. cases, presence of sputum positive and
cavitations on chest X-ray in index cases showed higher odds of being tuberculin positive
among household contacts but the differences were not significant. Conclusion: The study
has shown that HIV -infected PTB were less infectious to their household contacts than HIVnegative
patients. The study suggests that the more advanced HIV -associated
immunosuppresion among the PTB index cases, the less infectious is the PTB. The
transmissibility of TB may depend on the stage of HIV infection i.e patients who are
immunosuppressed are less likely to cavitate and have milder pulmonary lesions, and
therefore are less infectious than those patients who are at an early stage of HIV infection.
The presence of HIV in the community may not necessitate a change in the current policy in
the management of contacts in the general population.
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Keywords
EPIDEMIOLOGY AND BIOSTATISTICS