Table 2 Prevalence of Dirofilaria immitis antigen in dogs from southern Portugal according to independent variables and their categories

Gender

169

p = 0.297

  Female

79 (46.7)

6.3

2.1–14.2

  Male

90 (53.3)

12.2

6.3–20.8

Breed

167

p = 0.071

  Defined

93 (55.7)

5.4

1.8–12.1

  Mongrel

74 (44.3)

14.9

7.7–25.0

Fur length

81

p = 1.0

  Short

47 (58.0)

6.4

1.3–17.5

  Medium or long

34 (42.0)

5.9

0.7–19.7

Age (months)

155

p = ND

  [2–11]

31 (20.0)

0.0^a

0.0–11.2

  [12–83]

74 (47.7)

9.5

3.9–18.5

  [84–204]

50 (32.3)

16.0^a

7.2–29.1

Lifestyle

170

p = 0.352

  Domestic

157 (92.4)

8.9

5.0–14.5

  Stray

13 (7.6)

15.4

1.9–45.4

Housing

161

p = 1.0

  Exclusively or mainly indoors

69 (42.9)

8.7

3.3–18.0

  Mainly or exclusively outdoors

92 (57.1)

9.8

4.6–17.8

Macrocyclic lactones*

143

p = 0.128

  Yes

23 (16.1)

0.0

0.0–14.8

  No

120 (83.9)

10.8

5.9–17.8

Leishmania spp.

170

p = 1.0

  Negative

139 (81.8)

9.4

5.1–15.4

  Positive

31 (18.2)

9.7

2.0–25.7

Total

170

9.4

5.5–14.8