RISK FACTORS FOR PEDIATRIC TUBERCULOSIS INFECTION AND

DISEASE FOLLOWING EXPOSURE TO ADULT SOURCE CASES ON THE

PRAIRIES

Catherine Paulsen1, Courtney Heffernan1, L. Duncan Saunders2

Vern Hoeppner3, Richard Long1,2

1Department of Medicine, University of Alberta, 2School of Public Health, University of Alberta 3Department of Medicine, University of Saskatchewan

The “DTT” Project These data were collected as part of the “The

Determinants of Tuberculosis Transmission in the Canadian-born Population of the Prairie Provinces” or “DTT” project

This project was based on the understanding that:i. most cases of TB on the prairies occur in two

population groups, Aboriginal peoples and the foreign-born and

ii. ongoing transmission is a major obstacle to TB elimination in Aboriginal peoples 

Potential Canadian-born Transmitters on the Prairies in 2007-2008

30 Month Transmission Window

2007

20081

2

3

4

248

Possible vs Probable Transmitters

Characteristics of Probable Transmitters with and without Pediatric Contacts

Probable Transmitter Characteristic

Cases with Pediatric Contacts

(n=72)

Cases without Pediatric Contacts

(n=35)

p-value

Age (yrs.)15-44

>44

 49 (76.6%)23 (53.5%)

 15 (23.4%)20 (46.5%)

 0.013

SexMale

Female

 35 (59.3%)37 (77.1%)

 24 (40.7%)11 (22.9%)

 0.051

 Population Group

First NationsMétisOther

 46 (74.2%)15 (55.6%)11 (61.1%)

 16 (25.8%)12 (44.4%))7 (38.9%)

  

0.19

Community TypeFirst Nations Reserve

Métis SettlementMajor Metropolitan

Non-Major Metropolitan

 35 (83.3%)15 (65.2%)11 (42.3%)11 (68.8%)

 7 (16.7%)8 (34.8%)15 (57.7%)5 (31.2%)

  

0.006

LatitudeNorth of 53rd ParallelSouth of 53rd Parallel

 52 (69.3%)20 (62.5%)

 23 (30.7%)12 (37.5%)

 0.49

Proportion of Probable Transmitters with 0,1, 2 etc. Pediatric Contacts

0 1 2 3 4 5 6 7 8 9 ≥100

5

10

15

20

25

30

35

Number of Pediatric Contacts

Prop

orti

on o

f Pro

babl

e Tr

ansm

itte

rs (

%)

Contact-Numerous Transmitters

Of the pediatric contacts, 302 (59%) were attached to just 13 (18%) potential transmitters

Of these 13 contact-numerous transmitters: 9 were Female; 4 were Male 10 lived in First Nations Reserves; 2 in Métis

Settlements, 1 in a major metropolitan area 10 were 15-44 years of age; 3 were ≥ 45

Risk Factors for Transmission Events Among Fully Assessed Contacts

 Characteristic of Probable Transmitter 

Secondary Cases, TST Converters &

New TST Positives(n=151)

 Negative(n=174)

 p-value

Age of Transmitter15-44

>44

 117 (49.4%)34 (38.6%)

 120 (50.6%)54 (61.4%)

 0.085

Sex of TransmitterMale

Female

 57 (32.6%)94 (62.7%)

 118 (67.4%)56 (37.3%)

 <0.001

Population Group of Transmitter

First NationsMétisOther

 121 (50.0%)25 (62.5%)5 (11.6%)

  121 (50.0%)15 (37.5%)38 (88.4%)

  

<0.001

Smear Status of TransmitterPositive

Negative

 149 (47.0%)

2 (14.3%)

 162 (52.1%)12 (85.7%)

 0.014

Cavitation Status of Transmitter

CavitaryNon-Cavitary

 105 (45.7%)46 (48.4%)

 125 (54.3%)49 (51.6%)

  

0.65

Source Province of TransmitterAlberta

Saskatchewan

 29 (18.7%)

122 (71.8%)

 126 (81.3%)48 (28.2%)

 <0.001

Latitude of TransmitterNorth of 53 ParallelSouth of 53 Parallel

 118 (45.9%)33 (48.5%)

 139 (54.1%)35 (51.5%)

 0.70

 

Characteristics of Contacts with Transmission Events

Characteristic New TST Positive(n=70)

TST Converters(n=59)

Secondary Cases(n=22)

p-value

Age0-4

5-14

 29 (51.8%)41 (43.1%)

 16 (28.6%)43 (45.3%)

 11 (19.6%)11 (11.6%)

 0.10

SexMale

Female

 38 (46.3%)32 (46.4%)

 33 (40.3%)26 (37.7%)

 11 (13.4%)11 (15.9%)

  0.89

ProvinceAlberta

Saskatchewan

 10 (34.5%)60 (49.2%)

 14 (48.3%)45 (36.9 %)

 5 (17.2%)

17 (13.9%)

 0.36

Conclusions from this Preliminary Analysis

1/3 of probable transmitters had no pediatric contacts; while a few had many, many contacts

Transmitters with pediatric contacts were more likely to be younger, female and living on reserve

Probable transmitters were more likely to transmit to children if they were female, First Nations or Métis, smear-positive, and residing in Saskatchewan

Type of transmission event did not vary by age, sex or location of the child

Future Directions Data from Manitoba is forthcoming, and will be

incorporated into the analysis Logistic regression will be used to model

pediatric transmission events

Lessons learned will be shared and responded to at multiple levels: community, FNIHB Region, Province, and Interprovincial TB Working Group

AcknowledgementsWe would like to acknowledge the support and dedicated work of the many staff and students in Alberta & Saskatchewan. This study was funded by grants from the Canadian Institutes of Health Research (CIHR) and Health Canada’s First Nations and Inuit Health Branch (FNIHB) .

Questions?