Evidence of the presence of Borrelia burgdorferi in dogs and associated ticks in Egypt

R Elhelw,D Hamza,M Elhariri,H Farag,M Abuowarda,E Ismael

doi:10.1186/s12917-020-02733-5

Abstract

BackgroundBorrelia burgdorferi is the spirochete that causes Lyme Borreliosis (LB), which is a zoonotic tick-borne disease of humans and domestic animals. Hard ticks are obligate haematophagous ectoparasites that serve as vectors of Borrelia burgdorferi. Studies on the presence of Lyme borreliosis in Egyptian animals and associated ticks are scarce.MethodsThis study was conducted to detect B. burgdorferi in different tick vectors and animal hosts. Three hundred animals (dogs=100, cattle=100, and camels=100) were inspected for tick infestation. Blood samples from 160 tick-infested animals and their associated ticks (n=1025) were collected and examined for the infection with B. burgdorferi by polymerase chain reaction (PCR) and sequencing of the 16S rRNA gene. The identified tick species were characterized molecularly by PCR and sequencing of the ITS2 region.ResultsThe overall tick infestation rate among examined animals was 78.33% (235/300). The rate of infestation was significantly higher in camels (90%), followed by cattle (76%) and dogs (69%); (P = 0.001). Rhipicephalus sanguineus, Rhipicephalus (Boophilus) annulatus, and both Hyalomma dromedarii and Amblyomma variegatum, were morphologically identified from infested dogs, cattle, and camels; respectively. Molecular characterization of ticks using the ITS2 region confirmed the morphological identification, as well as displayed high similarities of R. sanguineus, H. dromedarii, and A. Variegatu with ticks identified in Egypt and various continents worldwide. Just one dog (1.67%) and its associated tick pool of R. sanguineus were positive for B. burgdorferi infection. The 16S rRNA gene sequence for B. burgdorferi in dog and R. sanguineus tick pool showed a 100% homology.ConclusionAnalyzed data revealed a relatively low rate of B. burgdorferi infection, but a significantly high prevalence of tick infestation among domesticated animals in Egypt, which possesses a potential animal and public health risk. Additionally, molecular characterization of ticks using the ITS2 region was a reliable tool to discriminate species of ticks and confirmed the morphological identification.

Highlights

Borrelia burgdorferi is the spirochete that causes Lyme Borreliosis (LB), which is a zoonotic tick-borne disease of humans and domestic animals
Prevalence of tick infestation in the studied animals Rhipicephalus sanguineus was detected in 69% of sampled dogs, Rhipicephalus (Boophilus) annulatus was detected in 76% of sampled cattle, and both Hyalomma dromedarii and Amblyomma variegatum were detected in 90% of examined camels
Species identification and phylogenetic analysis of ticks Ninety percent of examined camels from Cairo (Bassatin abattoir) and Matrouh governorates were infested with two species; H. dromedarii (93.3%) and A. variegatum (6.6%)

Summary

Introduction

Borrelia burgdorferi is the spirochete that causes Lyme Borreliosis (LB), which is a zoonotic tick-borne disease of humans and domestic animals. Lyme disease (LD) or the tick-borne relapsing fever (TBRF) is an emerging tick-borne multi-systemic zoonotic bacterial disease that has a worldwide distribution, caused by spirochetes of the Borrelia burgdorferi group and transmitted by ticks of the Ixodes ricinus complex [1]. Clinical signs differ according to the species of B. burgdorferi complex prevailing in the area, but most human patients show erythema migrans accompanied by flu-like symptoms [2, 3]. Dogs, act as sentinels for Lyme disease [4]. 5–10% of infected dogs show clinical signs. There is a significant underestimation of the Lyme disease prevalence in dogs, which represents a risk for disease spreading [5]. A previous survey on domestic animals detected borrelial DNA only in the adult ticks, mostly infesting sheep and cattle [6]

Methods

Results

Discussion

Conclusion