Disparities in Spatial Prevalence of Feline Retroviruses due to Data Aggregation: A Case of the Modifiable Areal Unit Problem
Table 1
(a) Descriptive characteristics of sampled cat population tested for FIV and FeLV infections in the US and Canada. (b) Descriptive statistics of FIV and FeLV seroprevalence (%), number of positive cats (cases), and number of cats tested for state, county, and postal code aggregation level.
(a)
Factors
Testeda
FIV positive
Prevalence (95% CI)b
FeLV positive
Prevalence (95% CI)b
Testing site
Veterinary clinic
19314
674
3.5 (3.2–3.8)
617
3.2 (2.9–3.4)
Shelter
9600
241
2.5 (2.2–2.8)
166
1.7 (1.5–2.0)
Age
Juvenile
15461
160
1.0 (0.9–1.2)
198
1.3 ( 1.1–1.5)
Adult
13453
755
5.6 (5.2–6.0)
585
4.4 (4.0–4.7)
Sex
Male intact
8649
372
4.3 (3.9–4.8)
240
2.8 (2.4–3.1)
Male castrated
6027
299
5.0 (4.4–5.5)
198
3.3 (2.9–3.8)
Female intact
9211
139
1.5 (1.3–1.8)
198
2.2 (1.9– 2.5)
Female spayed
4987
102
2.1 (1.7–2.5)
144
2.9 (2.4–3.4)
Unknown
40
3
7.5 (1.7–20.4)
3
7.5 (1.7–20.4)
Outdoor exposure
No
7142
99
1.4 (1.1–1.7)
136
1.9 (1.6–2.3)
Yes
17968
708
3.9 (3.7–4.2)
565
3.1 (2.9–3.4)
Unknown
3804
108
2.8 (2.3–3.4)
82
2.2 (1.7–2.7)
Health status
Healthy
22311
507
2.3 (2.1– 2.5)
379
1.7 (1.5–1.9)
Sick
6092
389
6.4 (5.8–7.0)
391
6.4 (5.8–7.1)
Unknown
511
19
3.7 (2.3–5.7)
13
2.5 (1.4–4.3)
Total number of cats tested for FIV and FeLV infection. Cats were tested at the same time for both FIV and FeLV infections.
bCI: confidence intervals for seroprevalence estimates with α = 0.05.
(b)
Infection
Aggregation level
Characteristicsa
Total
Mean
SDb
Range
FIV
State
Seroprevalence
3
2
0–13
Cases
915
18.67
35.14
0–221
Tested
28914
590.08
903.01
8–5732
County
Seroprevalence
4
5
0–50
Cases
915
2.64
5.28
0–59
Tested
28914
83.57
125.81
1–958
Postal code
Seroprevalence
4
7
0–100
Cases
915
1.43
1.78
0–26
Tested
28914
45.11
61.58
1–838
FeLV
State
Seroprevalence
3
3
0–20
Cases
783
15.98
25.25
0–145
Tested
28914
590.08
903.01
8–5732
County
Seroprevalence
3
4
0–33
Cases
783
2.26
4.24
0–47
Tested
28914
83.57
125.81
1–958
Postal code
Seroprevalence
3
6
0–100
Cases
783
1.22
2.12
0–19
Tested
28914
45.11
61.58
1–838
The descriptive statistics for seroprevalence pertain to mean value among states, counties, or postal codes. For example, min. and max. seroprevalence estimates for FIV among states are 0 and 13, respectively.
bStandard deviation.
