Background
Canine vector-borne diseases (CVBDs) represent a wide group of diseases of major significance for canine health. In addition to their veterinary importance, many of these diseases are of great zoonotic concern, posing a risk of potential transmission to humans. To date, there has been scant knowledge regarding the prevalence, distribution and risk factors of CVBDs in Greece. Therefore, the objectives of the present study were to update the current knowledge on the seroprevalence of
Dirofilaria immitis
,
Anaplasma
spp.,
Ehrlichia
spp. and
Borrelia burgdorferi
(
sensu lato
) in dogs in Greece and, furthermore, to assess possible environmental and any other risk factors associated with these infections. A total of 1000 apparently healthy and randomly selected dogs, presented in veterinary clinics, were involved at the national level (
n
= 66 municipalities). Serum samples were obtained from each individual dog and were tested using the SNAP
®
4Dx
®
Plus kit from IDEXX Laboratories. Possible risk factors were assessed using binary regression models, including dogs’ lifestyle, climatological parameters and the altitude of the region.
Results
Overall, 21.8% (95% CI: 19.4–24.5%) of the sampled dogs were found to be seropositive to at least one of the four pathogens examined. The most prevalent pathogen was
Ehrlichia
spp. (12.5%, 95% CI: 10.6–14.7) followed by
D. immitis
(9.0%, 95% CI: 7.8–11.5) and
Anaplasma
spp. (6.2%, 95% CI: 4.9–7.9). The lowest prevalence (0.1%) was recorded for
B. burgdorferi
(
s.l.
) where only one dog was found to be positive. Among the examined risk factors, low mean temperature was found to increase the prevalence of
Ehrlichia
spp. (
P
≤ 0.001) and
Anaplasma
spp. (
P
≤ 0.001), while low minimum temperature increased the prevalence of
D. immitis
(
P
≤ 0.001). In addition, low total annual rainfall had an effect of the prevalence of
Ehrlichia
spp. (
P
≤ 0.01). Altitude also had a significant effect on the prevalence of
D. immitis
(
P
≤ 0.05) and
Anaplasma
spp. (
P
≤ 0.01).
Conclusions
To our knowledge, this is the first large-scale seroepidemiological study of CVBDs in Greece. It has been evidenced that environmental factors such as temperature, rainfall and altitude can influence the prevalence and distribution of CVBDs.