A clinical evaluation of children under the age of five years who are household contacts of adults with sputum positive tuberculosis in Harare, Zimbabwe

OBJECTIVE: To determine the prevalence and risk factors for transmission of tuberculosis in children under five years of age who are household contact of sputum smear positive tuberculosis adults in Harare, Zimbabwe. DESIGN: Cross sectional study. SETTING: City Health Infectious Diseases Hospital Outpatient Department. SUBJECTS: 174 children in contact with 102 index cases. MAIN OUTCOME MEASURES: TB infection status in children according to modified WHO classification of tuberculosis. METHODS: Under five year old contacts of sputum smear positive TB adults were recruited over a three month period. A coded questionnaire was used to document the following: socio-demographic profile of caregivers, duration of stay with the index case and presenting complaints. Contacts were evaluated by clinical examination, Mantoux testing, HIV antibody testing and chest radiographs. RESULTS: Of the 174 children in contact with 102 index cases evaluated, 109 (62.6%) were Mantoux positive (> or = 10 mm), 42% had abnormal chest X-ray, with hilar lymphadenopathy being the commonest abnormality. Forty nine percent of the children evaluated had probable TB, 28% had suspected TB and 23% had no TB. High alcohol acid fast load (AAFB) in the index case was independently associated with probable and suspected TB (OR 2.27 95% CI (1.05 to 4.87). CONCLUSION: The documented high transmission rate among under five years contacts in the study justifies the need for strengthening contact tracing and appropriate therapeutic management of identified children.