Molecular prevalence of Borrelia burgdorferi, Ehrlichia canis, and Coxiella burnetii in dogs and associated ticks in Egypt: Emerging One Health challenging zoonoses

Abstract

Background and aim: Tick-borne pathogens pose a significant problem in canines, other animals, and humans worldwide. This study aimed to estimate the prevalence of Borrelia burgdorferi, Ehrlichia canis, and Coxiella burnetii in dogs and associated ticks in Egypt.

Materials and methods: Blood samples from 110 tick-infested dogs and 550 whole ticks (divided into 110 pools) were collected and tested for the targeted pathogens using polymerase chain reaction (PCR).

Results: Of the 110 dog blood samples, B. burgdorferi DNA was detected in three samples, E. canis in six samples, and C. burnetii in one kenneled dog. Among the 110 tick pools, B. burgdorferi was detected in four pools, E. canis in 12 pools, and C. burnetii in three pools from kenneled dogs. The overall prevalence of the three agents in dog and tick samples were 3.18%, 8.18%, and 1.81%, respectively. Simultaneous positive PCR reactions in both dogs and their associated tick pools were observed in four cases. B. burgdorferi and E. canis were simultaneously detected in two dogs and two tick pools, whereas C. burnetii was detected in one dog but not in any tick pools. The three agents were simultaneously detected in one dog, but none were found in the corresponding tick pools. A mixed infection of C. burnetii and B. burgdorferi was observed in one dog and one tick pool.

Conclusion: Molecular diagnosis is the most reliable method for detecting B. burgdorferi, E. canis, and C. burnetii in dogs and associated ticks. E. canis showed the highest prevalence in both dog and tick samples followed by B. burgdorferi while C. burnetti showed the lowest prevalence. The potential transmission of these diseases from companion dogs to humans through ticks presents a significant challenge for the One Health concept.

Keywords: Rhipicephalus; borreliosis; coxillosis; ehrlichiosis; pets.

Figure-1

A Google map illustrating the sampling locations [Source: Google Earth].

Figure-2

The dog-brown tick (Rhipicephalus sanguineus) collected from household and kenneled dogs. Photos showing the whole tick (left) and mouth with the front part (right) magnified using a stereomicroscope (10× magnification).

Figure-3

Polymerase chain reaction amplification results for specific detection of E. canis in dog blood samples and tick pools DNA based on the PER2 of 16S rRNA gene primer. M: 100-bp DNA size marker; 1 and 2 lanes: Tick DNA; lanes 3–7: Dog blood DNA; and P: Positive control DNA. Lanes 1–7 show the positive 451-bp amplicons specific for E. canis. E. canis=Ehrlichia canis.

Figure-4

PCR analysis of the B. burgdorferi Bp gene in DNA extracted from dog blood and brown tick pools. Lanes 1–4: Positive 577-bp amplicons specific for B. burgdorferi from household dogs and attached ticks; lane 5: positive control DNA and M: DNA size marker (100 bp). B. burgdorferi=Borrelia burgdorferi. PCR=Polymerase chain reaction.

Figure-5

Nested PCR detection of the Coxiella burnetii htpAB-IS1111 gene in DNA extracted from dog blood and attached brown tick pools. M: DNA size marker (100 bp); lanes 3–6: DNA from dog blood samples and tick pools showing positive 260-bp specific amplicons; lane 1: Positive control DNA and lane 2: Negative control (master mix, primers, and nuclease-free water). PCR=Polymerase chain reaction.