Molecular Detection of Spotted Fever Group Rickettsiae Associated with Ixodid Ticks in Egypt

Abstract

Tick-borne diseases comprise a complex epidemiological and ecological network that connects the vectors, pathogens, and a group of host species. The aim of this study was to identify bacteria from the genus Rickettsia associated with ixodid ticks infesting camels and cows in Egypt. Ticks were collected from 6 different localities: Qina, Giza, Qalet El Nakhl, New Valley, El Arish, and Minufia, from July to October 2008. Species were identified using PCR, followed by sequencing. The gltA and rOmpA genes were used for the initial detection of Rickettsia spp. Further characterization of positive samples utilized primers targeting rOmpB, sca4, and intergenic spacers (mppA-purC, dksA-xerC, and rpmE-tRNA(fMet)). Cows were infested with Hyalomma anatolicum excavatum and Boophilus annulatus. Camels were infested with Hyalomma dromedarii, H. impeltatum, and H. marginatum marginatum. Approximately 57.1% of H. dromedarii ticks collected from Qalet El Nakhl were infected with Rickettsia africae, exhibiting 99.1-100% identity to reference strains. Within H. impeltatum, 26.7% and 73.3% of ticks from El Arish were infected with R. africae and R. aeschlimannii, with 98.3-100% and 97.9-100% identity, respectively. Furthermore, 33.3% of H. marginatum marginatum ticks in Qalet El Nakhl were infected with the same two species as H. impeltatum, demonstrating 99.1-100% and 99.3-100% identity, respectively. By comparing percent identities and phylogenetic relationships, R. africae is identified for the first time in Egypt, in addition to R. aeschlimannii, which exhibits 100% identity with the Stavropol strain in GenBank. In conclusion, the obtained data underscore the medical and veterinary importance of tick-borne rickettsioses, which necessitate further investigation by authorities in Egypt. Moreover, additional characterization of these rickettsial isolates should be performed to designate their strains, using a polyphasic strategy combining genotypic and phenotypic tests, to facilitate their deposition in the rickettsial collection of the WHO and/or ATCC.

Molecular detection of Rickettsia aeschlimannii in Hyalomma spp. ticks from camels (Camelus dromedarius) in Nigeria, West Africa

“…The percentage detected in this study is higher than the prevalence of 17.6% of R. aeschlimannii DNA reported earlier in cattle ticks [Amblyomma variegatum, Rhipicephalus (Boophilus) annulatus and Rhipicephalus evertsi (all: Ixidida: Ixodidae)] from southwest Nigeria (Reye et al, 2012), which suggests that this bacterium is endemic and widely spread in several tick populations in Nigeria. The high incidence of detection of R. aeschlimannii DNA in H. rufipes ticks in this study is similar to that in earlier reports on the same tick species in Senegal, West Africa and in Egypt, North Africa (Mediannikov et al, 2010;Abdel-Shafy et al, 2012). This lends further credence to the role of H. rufipes as a vector of R. aeschlimannii in Africa.…”

“…In this study, R. aeschlimannii was not detected in H. dromedarii ticks, a finding in agreement with the report of Abdel‐Shafy et al . (), who conducted a similar study on camel and cattle ticks in Egypt, but which disagrees with other studies conducted in Sudan, Tunisia, Algeria and Israel, where R. aeschlimannii was detected in H. dromedarii ticks (Loftis et al ., ; Demoncheaux et al ., ; Djerbouh et al ., ; Kleinerman et al ., ). Similarly, H. impressum ticks were negative for R. aeschlimannii DNA in this study, which is in agreement with a previous report (Parola et al ., ).…”

“…All samples positive for Rickettsia spp. gltA were characterized by targeting the 178-189 bp and 630 bp outer membrane protein A (ompA) gene fragments by real-time and conventional PCR, respectively, as previously described (Harrus et al, 2011;Abdel-Shafy et al, 2012). Further, Rickettsia spp.…”

Vector-borne bacteria in blood of camels in Iran: New data and literature review

“…have been detected in camel blood serum with prevalences of up to 83% [21,58] and R. aeschlimannii, R. africae, R. sibirica mongolitimonae and Rickettsia sp. have been identified in several tick species collected from camels [20,[59][60][61][62][63][64][65][66]. Despite this, there are no reports on diseases in camels caused by these organisms.…”

Molecular epidemiology and phylogeny of spotted fever group Rickettsia in camels ( Camelus dromedarius ) and their infesting ticks from Tunisia

“…Moreover, in Africa, several other tick species belonging to Hyalomma genus are involved in the transmission of R. aeschlimannii which may explain its wide distribution in this continent (Beati, Meskini, Thiers, & Raoult, ). Particularly, H. marginatum marginatum and H. m. rufipes were considered as vectors of this rickettsial species in Senegal and Egypt (Abdel‐Shafy, Allam, Mediannikov, Parola, & Raoult, ; Mediannikov et al, ). It has also been reported in Rhipicephalus appendiculatus from South Africa (Pretorius & Birtles, ) and in Haemaphysalis punctata from Spain (Portillo et al, ).…”