Abstract
Rickettsioses including their pathogens, vectors, and hosts have an epidemiological importance and zoonotic importance. The objective of the present article was to define the prevalence and genotypic properties of Rickettsia in camels and their ticks in Egypt. Sixty one blood samples and 99 adult ticks were taken from camel hosts from Cairo, Giza and Sinai, during a period extending from 2013 to 2014. Based on the morphological identification of both male and female tick specimens, 91.9 % of the collected ticks were Hyalomma dromedarii. The prevalence of Rickettsia in camels using Gimenez staining technique and PCR was 0 and 41 %, respectively. The rickettsiae infection in ticks recorded 10.1 and 1.01 %, by Gimenez stain and PCR, respectively. Further, the phylogenetic analysis was conducted based on the sequences of OmpA and gltAgenes and three intergenic spacers (mppA, dksA and rpmE) of Rickettsia species. The phylogenetic analyses revealed a novel strain of Rickettsia africae in Hyalomma marginatum that was collected from camel in Sinai province. In addition, the phylogenetic analysis based on Clustal omega suggested that Rickettsia sequences which detected in camels were R. africae. Moreover, the highest Rickettsial infection rate was recorded in age groups of 17 to 19 years (80.0 %), Abady camel breeds (56.8 %) and ticks-infested camels (42.8 %). Concerning hematological changes, macrocytic anemia and leucopenia were recorded in camels with rickettsioses. The molecular characterization of Rickettsia detected in camels and their tick vectors will help in a better understanding of the epidemiological approach of rickettsioses in Egypt.
Highlights
Rickettsioses are considered emerging and re-emerging zoonotic vector-borne diseases (Parola and Raoult, 2001; Dantas-Torres et al, 2012; Kernif et al, 2012b; Parola et al, 2013)
The present results revealed that the Egyptian new isolates were similar to R. africae (KX819299, KX819298, KX819297, KX819295 and KX819296) and closely matching to the reference counterparts previously recorded in Saini-Egypt (HQ335132.1, HQ335126.1, HQ335143.1, HQ335138.1 and HQ335144.1), respectively (Table 3).the partial sequence of outer membrane protein A (OmpA) gene of Rickettsia amplified from camel showed 48.68 % similarity with R. africae accession no
The results revealed that the Rickettsia spp. detected in camel from Sinai province was closely matching to R. africae
Summary
Rickettsioses are considered emerging and re-emerging zoonotic vector-borne diseases (Parola and Raoult, 2001; Dantas-Torres et al, 2012; Kernif et al, 2012b; Parola et al, 2013). Ticks are considered secondary to mosquitoes in their ability to transmit diseases (Hillyard, 1996) They are the main vectors and reservoirs of Rickettsia spp.; especially SFG Rickettsiae that were transmitted transstadially through the developmental stages and transovarial (Raoult and Roux, 1997; Anderson and Magnorelli, 2008; Socolovschi et al, 2009b). SFG were detected in Rhipicephalus sanguineus and Hyalomma spp. from Sinai (Lange et al, 1992; Loftis et al, 2006ab). The objectives of this study were the determination of the prevalence of tick-borne rickettsioses in camels and their ixodid tick vectors at different provinces in Egypt, in addition the molecular characterization of novel genotypes of Rickettsia compared to the previously published genotypes. The genotypic relationship between these Rickettsia species and previously recorded worldwide is targeted by OmpA, gltA, mppA, dksA and rpmE sequences alignment with GenBank related records
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