Table 1

Univariable analysis for identification of environmental factors associated with a positive diagnosis of Aspergillus species in air samples during the first 12-month period: May 1, 2012 to April 23, 2013

VariableCategoryNegativePositiveCrude OR95% CIP value
N = 421 (100%)N = 62 (100%)
Park geographyWest65 (15)4 (6)1ReferenceNA
Central93 (22)22 (34)3.841.27, 11.640.01
East263 (63)36 (60)2.220.77, 6.450.14
InfrastructureIndoor with HEPA and other infection control measures109 (26)6 (10)1ReferenceNA
Indoor without HEPA and other infection control measures130 (31)31 (50)4.331.75, 10.72< 0.01
Outdoor182 (43)25 (40)2.51.00, 6.250.05
InfrastructureIndoor with HEPA and other infection control measures109 (26)6 (10)1ReferenceNA
Indoor without HEPA and other infection control measures130 (31)31 (50)4.331.75, 10.72< 0.01
Outdoor182 (31)25 (40)2.51.00, 6.250.05
OutdoorNo239 (57)37 (60)1ReferenceNA
Yes182 (43)25 (40)0.890.52, 1.530.66
Outside accessNo124 (29)14 (23)1ReferenceNA
Yes297 (71)48 (77)1.430.76, 2.680.26
Sunlight exposureNo161 (38)23 (37)1ReferenceNA
Yes260 (62)39 (63)1.050.61, 1.820.86
Pool presentNo134 (32)27 (44)1ReferenceNA
Yes287 (68)35 (56)0.610.35, 1.040.06
Substrate humidNo294 (70)38 (61)1ReferenceNA
Yes127 (30)24 (39)1.460.84, 2.540.17
Fans onNo250 (59)49 (79)1ReferenceNA
Yes171 (41)13 (21)0.390.20, 0.74< 0.01
Substrate typeConcrete360 (85)54 (87)1ReferenceNA
Dirt39 (9)7 (11)1.20.51, 2.810.68
Snow22 (6)1 (2)0.30.04, 2.240.24
Organic matter in areaNo325 (77)37 (60)1ReferenceNA
Yes96 (23)25 (40)2.211.31, 3.99< 0.01
Wood substrate in areaNo292 (69)35 (56)1ReferenceNA
Yes129 (31)27 (44)1.751.02, 3.000.04
Construction in areaNo413 (98)60 (97)1ReferenceNA
Yes8 (2)2 (3)1.720.36, 8.290.49
Construction in parkNo310 (74)47 (76)1ReferenceNA
Yes111 (26)15 (34)0.890.48, 1.650.71
Warm months of June to OctoberNo237 (56)36 (58)1ReferenceNA
Yes184 (44)26 (42)0.930.54, 1.590.79
Ave temperature (C)11.7 to 16.7163 (39)26 (42)1.310.67, 2.530.42
17.2 to 18.9131 (31)16 (29)1ReferenceNA
19.4 to 25.6127 (30)20 (29)1.290.64, 2.590.47
Ave humidity (%)29 to 64159 (38)30 (48)1.460.72, 2.990.29
65 to 7193 (22)12 (19)1ReferenceNA
72 to 81169 (40)20 (33)0.920.43, 1.950.82
Wind directionOn shore351 (83)48 (67)1ReferenceNA
Along shore70 (17)14 (23)1.460.77, 2.800.25
Wind speed (mph)2 to 5157 (37)32 (52)1ReferenceNA
6 to 12264 (63)30 (48)0.560.33, 0.950.03
Precipitation (inches)0462 (100)621ReferenceNA
0.01 to 0.030 (0)0NDNDND
Animal variablesNo210 (50)24 (39)1ReferenceNA
Yes211 (50)38 (61)1.580.92, 2.710.1
Aspergillosis case in the areaNo407 (97)61 (98)1ReferenceNA
Yes13 (3)1 (2)0.480.06, 3.680.47
Breeding seasonNo383 (91)57 (92)1ReferenceNA
Yes38 (9)5 (8)0.880.34, 2.330.8
  • *During June to October, the monthly average temperature is above the annual average temperature (17.7°C) and the monthly average rainfall is less than 13 mm (0.5 inches) in San Diego, CA.

  • HEPA, high-efficiency particulate air filtration system; NA, not applicable; ND, not determined.