Seroprevalence and associated risk factors for vector-borne pathogens in dogs from Egypt

Abstract

Background: Dogs play an important role as reservoirs of many zoonotic vector-borne pathogens worldwide, yet reports of canine vector-borne diseases (CVBDs) in Egypt are scarce.

Methods: Serum samples were collected from pet dogs (n = 500) of the three most common breeds (German Shepherd, Rottweiler and Pit Bull) in five Governates of Cairo (n = 230), Giza (n = 110), Al-Qalyubia (n = 60), Al-Gharbia (n = 60) and Kafr El-Sheikh (n = 40) with a hot desert climate. The presence of antibodies to Anaplasma spp. (A. phagocytophilum, A. platys), Ehrlichia spp. (E. canis, E. chaffeensis, E. ewingii), Borrelia burgdorferi (s.l.) and Dirofilaria immitis were assessed using IDEXX SNAP^® 4Dx^® ELISA tests. For each pathogen, risk factors (i.e. geographical area, keeping condition, sex, age, breed, tick infestation, weekly sanitation of dog enclosures and application of ectoparasiticides) were evaluated by logistic regression approach.

Results: In total, 18.2% (n = 91, 95% CI 15.1-21.8) of dogs scored seropositive for at least one pathogen, the most frequent being Ehrlichia spp. (n = 56; 11.2%; 95% CI 8.7-14.3) followed by Anaplasma spp. (n = 33; 6.6%, 95% CI 4.7-9.1), Borrelia burgdorferi (s.l.) (n = 9; 1.8%, 95% CI 0.9-3.4) and D. immitis (n = 7; 1.4%, 95% CI 0.9-2.9). In the tested population, 15.4% (95% CI 12.5-18.8) of dogs were exposed to a single pathogen while 2.4 (95% CI 1.4-4.2) and 0.4% (95% CI 0.1-1.4) were simultaneously exposed to two or three pathogens, respectively. Major risk factors associated with VBDs were living outdoors (Anaplasma spp., P = 0.0001; Ehrlichia spp., P = 0.0001), female sex (Ehrlichia spp., P = 0.005), German Shepherd breed (Anaplasma spp., P = 0.04; Ehrlichia spp., P = 0.03), tick infestation (Anaplasma spp., P = 0.0001; Ehrlichia spp., P = 0.0001; B. burgdorferi (s.l.), P = 0.003; D. immitis, P = 0.02), irregular sanitation (Anaplasma spp., P = 0.0001; Ehrlichia spp., P = 0.0001; B. burgdorferi (s.l.), P = 0.002; D. immitis, P = 0.01) and not using ectoparasiticides (Anaplasma spp., P = 0.0001; Ehrlichia spp., P = 0.0001; B. burgdorferi (s.l.), P = 0.007).

Conclusion: To our knowledge, this is the first large-scale seroepidemiological study of CVBDs in Egypt. Considering that all of the detected pathogens are potentially zoonotic, effective ectoparasite control strategies, regular examination of pet dogs and successful chemoprophylaxis are advocated.

Keywords: Anaplasma; Borrelia; Canine vector-borne pathogens; Dirofilaria; Egypt; Ehrlichia; One-health; Zoonosis.

Fig. 1

Map indicating Governorates where animals included in the study were sampled