Passive versus active tuberculosis case finding and isoniazid preventive therapy among household contacts in a rural district of Malawi.
METHODS
Thyolo district, rural Malawi.


OBJECTIVE
To compare passive with active case finding among household contacts of smear-positive pulmonary tuberculosis (TB) patients for 1) TB case detection and 2) the proportion of child contacts aged under 6 years who are placed on isoniazid (INH) preventive therapy.


METHODS
Cross-sectional study.


METHODS
Passive and active case finding was conducted among household contacts, and the uptake of INH preventive therapy in children was assessed.


RESULTS
There were 189 index TB cases and 985 household contacts. Human immunodeficiency virus (HIV) prevalence among index cases was 69%. Prevalence of TB by passive case finding among 524 household contacts was 0.19% (191/100000), which was significantly lower than with active finding among 461 contacts (1.74%, 1735/100000, P = 0.01). Of 126 children in the passive cohort, 22 (17%) received INH, while in the active cohort 25 (22%) of 113 children received the drug. Transport costs associated with chest X-ray (CXR) screening were the major reason for low INH uptake.


CONCLUSIONS
Where the majority of TB patients are HIV-positive, active case finding among household contacts yields nine times more TB cases and is an opportunity for reducing TB morbidity and mortality. The need for a CXR is an obstacle to the uptake of INH prophylaxis.
Zachariah
R
R
Operational Research (HIV/TB), Medical Department, Médecins sans Frontières-Brussels Operational Centre, Brussels, Belgium. zachariah@internet.lu
Spielmann
M P
MP
Harries
A D
AD
Gomani
P
P
Graham
S M
SM
Bakali
E
E
Humblet
P
P
D000293:Adolescent; D000328:Adult; D000368:Aged; D000995:Antitubercular Agents / Q000627:therapeutic use; D002675:Child, Preschool; D015897:Comorbidity; D016358:Contact Tracing / Q000379:methods*; D003430:Cross-Sectional Studies; D005260:Female; D015658:HIV Infections / Q000453:epidemiology; D006801:Humans; D007538:Isoniazid / Q000627:therapeutic use; D008295:Malawi / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012424:Rural Population; D014397:Tuberculosis, Pulmonary / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000517:prevention & control*
D000995:Antitubercular Agents; D007538:Isoniazid