Figures
- FIGURE 1
Age- and sex-adjusted incidence of paediatric tuberculosis (TB) by population group and time period in Alberta, 1990–2014. Population figures are from Statistics Canada. CBO: Canadian-born “other”; RFN: registered First Nations; FB: foreign born.
- FIGURE 2
Paediatric tuberculosis (TB) cases by 5-year period and population group in Alberta, 1990–2014. CBO-CB: Canadian-born “other” with Canadian-born parents; CBO-FB: Canadian-born “other” with one or more foreign-born parents; RFN: registered First Nations; FB: foreign born.
- FIGURE 3
Paediatric tuberculosis (TB) in Alberta by method of detection and strategically placed TB elimination activities. The dotted lines highlight contacts with a single International Classification of Diseases Ninth Revision (ICD-9) code of 010.0 (primary tuberculous complex). Of the CBO-FB children without a source case in Alberta (n=9), five could, on the basis of their travel history or their unique Mycobacterium tuberculosis DNA fingerprints, be reasonably said to have acquired their infection overseas. PTB: pulmonary TB; CBO-CB: Canadian-born “other” with Canadian-born parents; CBO-FB: Canadian-born “other” with one or more foreign-born parents; RFN: registered First Nations; FB: foreign born; ME: molecular epidemiology; CNS: central nervous system; LTBI: latent TB infection.
Tables
- TABLE 1
The incidence of paediatric tuberculosis (TB) in Alberta by population group and age, 1990–2014
Grouping Cases n (%) Observation person-years (×100 000)# Incidence rate RRadj (95% CI) Unadjusted Adjusted (95% CI)¶ By population group Overall 176 (100) 159.37 1.10 1.20 (1.01–1.20) CBO 61 (36) 143.85 0.42 0.54 (0.39–0.66) 1.00 RFN 56 (34) 7.50 7.46 8.34 (6.13–11.07) 16.37 (10.91–24.48) FB 59 (30) 8.01 7.36 9.29 (6.43–12.95) 18.25 (11.59–28.30) By age and population group 0–4 years Overall 78 (100) 5.31 1.47 1.47 (1.16–1.83) CBO 39 (50) 4.95 0.79 0.79 (0.56–1.08) 1.00 RFN 23 (29) 0.22 10.48 10.48 (6.64–15.72) 13.31 (7.59–22.85) FB 16 (21) 0.13 12.22 12.22 (6.99–19.85) 15.53 (8.10–28.44) 5–14 years Overall 98 (100) 10.63 0.92 0.92 (0.75–1.12) CBO 22 (22) 9.43 0.23 0.23 (0.15–0.35) 1.00 RFN 33 (34) 0.53 6.21 6.22 (4.29–8.75) 26.70 (15.10–48.10) FB 43 (44) 0.67 6.41 6.41 (4.64–8.64) 27.50 (16.09–48.28) RRadj: age-sex adjusted incidence rate ratio; CBO: Canadian-born “other”; RFN: registered First Nations; FB: foreign born. #: based upon Canadian censuses conducted in 1986, 1991, 1996, 2001, 2006 and 2011, as well as registered First Nations population estimates provided by Indian and Northern Affairs Canada; ¶: adjusted rates by population group were standardised by age and sex, while adjusted rates by age and population group were standardised by sex.
- TABLE 2
Demographic and clinical characteristics of paediatric tuberculosis (TB) cases by population group in Alberta, 1990–2014
Characteristics Population group Total p-value# RFN CBO-CB CBO-FB FB Cases 56 18 43 59 176 Age years 0.001 <5 23 (41) 10 (56) 29 (67) 16 (27) 78 (44) 5–14 33 (59) 8 (44) 14 (33) 43 (73) 98 (56) Sex 0.09 Female 25 (45) 10 (56) 30 (70) 35 (59) 100 (57) Male 31 (55) 8 (44) 13 (30) 24 (41) 76 (43) Disease site 0.03 Pulmonary 51 (91) 14 (78) 36 (84) 41 (70) 142 (81) Extrapulmonary¶ 5 (9) 4 (22) 7 (16) 18 (31) 34 (19) Method of detection <0.001 Contact tracing 52 (93) 14 (78) 27 (63) 15 (25) 108 (61) Symptoms 4 (7) 4 (22) 14 (33) 37 (63) 59 (34) Other screening+ 0 (0) 0 (0) 2 (5) 7 (12) 9 (5) Culture status 0.47 Positive 22 (39) 6 (33) 16 (37) 34 (58) 78 (44) Negative 32 (57) 9 (50) 24 (56) 25 (42) 90 (51) Unknown§ 2 (4) 3 (17) 3 (7) 0 (0) 8 (5) Data are presented as n or n (%), unless otherwise stated. CBO-CB: Canadian-born “other” with Canadian-born parents; CBO-FB: Canadian-born “other” with foreign-born parents; RFN: registered First Nations; FB: foreign born. #: Pearson's Chi-squared test or Fisher's exact test if cells contain values <5; ¶: Extrapulmonary includes all cases with an International Classification of Diseases Ninth Revision (ICD-9) code of 013 (TB of meninges and the central nervous system) and/or 018 (miliary TB) with or without disease in other sites. It also includes the single ICD-9 codes 014 (TB of the intestines, peritoneum and mesenteric glands), 015 (TB of the bones and joints), 016 (TB of the genito-urinary system) and 017 (TB of other organs); +: other screening includes immigration medical evaluations, international adoptee screening and incidental findings; §: unknown means that no diagnostic specimens were submitted.
- TABLE 3
Culture status of paediatric tuberculosis (TB) cases in Alberta by demographic and clinical characteristics, 1990–2014
Characteristics Total Culture specimen p-value# OR (95% CI) Negative Positive Cases 168 90 (54) 78 (46) Age years 0.01 <5 71 46 (65) 25 (35) 1 5–14 97 44 (45) 53 (55) 2.21 (1.16–4.21) Sex 0.23 Female 93 46 (50) 47 (51) 1 Male 75 44 (59) 31 (41) 0.69 (0.37–1.27) Population group 0.20 CBO-CB 15 9 (60) 6 (40) 1 CBO-FB 40 24 (60) 16 (40) 1.00(0.30–3.36) RFN 54 32 (59) 22 (41) 0.97(0.30–3.11) FB 59 25(42) 34(58) 0.49(0.15–1.56) Disease site 0.02 Pulmonary 136 79 (58) 57 (42) 1 Extrapulmonary 32 11 (34) 21 (66) 0.38 (0.17–0.85) Method of detection <0.001 Symptoms 58 19 (33) 39 (67) 1 Contact tracing¶ 101 69 (68) 32 (32) 0.22 (0.11–0.45) Other screening+ 9 2 (22) 7 (78) 1.71 (0.32–9.01) Data are presented as n or n (%), unless otherwise stated. CBO-CB: Canadian-born “other” with Canadian-born parents; CBO-FB: Canadian-born “other” with foreign-born parents; RFN: registered First Nations; FB: foreign born; OR: odds ratio (crude and unadjusted for any other variables in the table). #: Pearson's Chi-squared test or Fisher's exact test if cells contain values <5. ¶: of the 101 children whose method of detection was contact tracing and who had one or more specimens submitted for culture, 85 had primary pulmonary TB complex alone (see figure 3). Of these only 22 (25.9%) were culture-positive. +: other screening includes immigration medical evaluations, international adoptee screening and incidental findings.
- TABLE 4
Utility of conventional epidemiology (CE) for the identification of paediatric tuberculosis (TB) source cases
Characteristic Total Source case identified by CE OR (95% CI) Yes No Cases 176 111 (63) 65 (37) Age years <5 78 54 (69) 24 (31) 1.0 5–14 98 57 (58) 41 (42) 1.62 (0.87–3.03) Sex Female 100 59 (59) 41 (41) 1.0 Male 76 52 (68) 24 (32) 0.66 (0.35–1.24) Population group CBO 61 43 (71) 18 (30) 1.0 RFN 56 53 (95) 3 (5) 0.14 (0.04–0.50) FB 59 15 (25) 44 (75) 7.01 (3.14–15.66) Method of detection Contact tracing 108 107 (99) 1 (1)# Symptoms 59 4 (4)¶ 55 (97) Other screening+ 9 0 (0) 9 (100) Data is presented as n or n (%), unless otherwise stated. CBO: Canadian-born “other”; RFN: registered First Nations; FB: foreign born; OR: odds ratio. #: this child was a close contact of a relative who lived in a neighbouring province-there was no source case in Alberta; ¶: four children were index cases with symptoms and their source cases were identified through reverse contact tracing; +: other screening includes immigration medical evaluations, international adoptee screening and incidental findings.
- TABLE 5
Utility of molecular epidemiology (ME) for the identification of paediatric tuberculosis (TB) source cases
Characteristic Total# Source case identified by CE No source case identified by CE Subtotal Identified by ME Subtotal Identified by ME¶ Cases 78 35 34 (97) 43 6 (14) Age years <5 25 11 11 (100) 14 4 (29) 5–14 53 24 23 (96) 29 2 (7) Sex Female 47 20 19 (95) 27 3 (11) Male 31 15 15 (100) 16 3 (19) Population group CBO 22 12 11 (92) 10 4 (40) RFN 22 20 20 (100) 2 1 (50) FB 34 3 3 (100) 31 1 (3) Method of detection Symptoms 39 4 4 (100) 35 6 (17) Contact tracing 32 31 30 (97) 1 0 (0) Other screening+ 7 0 0 (0) 7 0 (0) Data are presented as n or n (%), unless otherwise stated. CE: conventional epidemiology; CBO: Canadian-born “other”; RFN: registered First Nations; FB: foreign born. #: total culture-positive cases; ¶: odds ratios of paediatric TB cases with source cases identified by ME only versus paediatric TB cases without source cases identified by ME or CE for various characteristics are as follows: age 5–14 years (0.1852 (95% CI 0.03–1.17)); male sex (1.8462 (95% CI 0.33–10.49)); FB population group (0.0467 (95% CI 0.005–0.47)); detection by symptoms (3.7458 (95% CI 0.19–73.45)). +: other screening includes immigration medical evaluations, international adoptee screening and incidental findings.
