Abebe et al. BMC Public Health 2012, 12:504 http://www.biomedcentral.com/1471-2458/12/504 microscopy, culture and/or cytology suggested TB indi- vidually or in combination. FNA FNA was performed using a 22-gauge needle attached to a 10-cc syringe. The aspirates were macroscopically eval- uated for caseation. Two smears were prepared from each aspirate and air dried on site. The remainder of the aspirate was washed into 1 ml physiological saline for culture and transported to Jimma University Specialized Hospital in a cold box. FNA samples were kept at −20°C till transported in cold box by postal system to Armauer Hansen Research Institute (AHRI) in Addis Ababa for culture. All samples were transported within a maximum of 5 days. One slide of a smear was stained with the Ziehl- Neelsen method [7] and examined for the presence of AFB by an experienced laboratory technician. The sec- ond smear was stained with Wright stain and cytological analysis was done by the study pathologists at Jimma University. TB lymphadenitis diagnosis by cytology was made by observation of the presence of epitheloid cell granulomas and caseous necrosis with or without Lan- ghan’s giant cells [8,9]. Culture At the AHRI, the FNA samples were processed by the standard N-acetyl L-cysteine (NALC)-NaOH method [10] and concentrated at 3000 × g for 15 minutes. The sediment was reconstituted to 2.5 ml with phosphate buffer pH 6.8, to make the inoculums for the cultures. Two Lowenstein-Jensen slants, one containing 0.75% glycerol and the other containing 0.6% pyruvate, were inoculated with the sediment and incubated at 37°C. Cultures were considered negative when no colonies were seen after 8 weeks of incubation. HIV Screening All consenting TB lymphadenitis suspects were tested for HIV after counseling. Testing for HIV was done as per Ethiopian national guidelines. HIV screening was performed using the KHB test (Shanghai Kehua Bio- Engineering Ltd, Shanghai, China; 2008). A positive sam- ple was retested using the STAT-PAK test (Chembio Diagnostic System Inc, Medford, NY, USA; 2008). Data analysis Data were double entered using Epi-data version 3.1 (Epi-data, Norway, 2006). For analysis, the data were exported to SPSS version 15.0 statistical software (SPSS Inc. Chicago, 2007). Descriptive analysis was done for the socio-demographic variables and prevalence of TB lymphadenitis. Logistic regression was done to assess factors independently associated with TB lymphadenitis Page 3 of 7 in terms of the crude odds ratio and its 95% confidence interval (CI). A p-value less than or equal to 0.05 was considered significant. Ethical consideration The study was approved by the ethical review commit- tees of Jimma University, AHRI and the Institute of Tropical Medicine in Belgium. A workshop was held with the local community leaders, Kebele chair persons and Woreda health offices representatives to create awareness about the purpose of the study. Written con- sent was obtained from the study participants. First the head of the house gave consent. Subsequently depending on the information from the head of the house all the suspects gave consent before administering the question- naire and undergoing FNA. New TB cases identified were immediately referred to the nearby health facility for treatment. Results Characteristics of the TB lymphadenitis suspects A total of 30,040 individuals 15 years or older in 10,882 households were screened for TB lymphadenitis. Com- plete data were available from 9 Kelebes (27,597 indivi- duals 15 years or older) while one Kebele was excluded from analysis because of incomplete data. After inter- view 87 TB lymphadenitis suspects were identified. The mean age (±SD) of the suspects was 33.1 (±11.3) years. Most (72.4%) were women and married (81.6%). Thirty one (35.6%) lived in close contact with animals and 45 (53.5%) used to drink raw milk. Prevalence of TB Lymphadenitis On the basis of FNA smear microscopy for AFB, cy- tology and culture 16 (18.4%) of the lymph nodes were diagnosed as tuberculous. Smears were positive in 2, cul- ture in 6 and cytology in 13 of the suspects. The micro- scopic features of FNA cytology of the TB lymphadenitis showed epithelial histocytes with giant cells in 8 cases, epithelial histocytes with caseous necrosis in 2 cases and caseous necrosis alone in 3 cases. Three of these 16 cases were positive by both culture and FNA cytology. The mycobacteria isolated in 6 cases were identified as Mycobacterium tuberculosis based on RD typing. The remaining 10 cases that were negative on culture but positive on smear and/or cytomorphology were also con- sidered to be tuberculous. The distribution of TB lymph- adenitis cases per kebele is indicated in Table 1. The prevalence of TB lymphadenitis was 58.0 per 100,000 people (16/27,597) (95% CI 35.7-94.2). Other diagnosis of the lymph nodes include: reactive lymphadenitis (57), pyogenic lymphadenitis (6), benign mesenchymal neo- plasia (6) and non-specific lymphadenitis (5).