Molecular screening of ticks for the presence of Rickettsia species: A public health concern

Tick-borne rickettsioses are emerging and re-emerging diseases of public health concern caused by over 30 species of Rickettsia. Ticks are obligate hematophagous arthropods with over 700 species of Ixodid ticks known worldwide. The escalating geographical dispersal of tick vectors and concomitant increase in the incidences of tick-borne diseases have fueled interest in the ecology of tick-borne pathogens. This review focuses on aspects of the Rickettsia pathogen, including biology, taxonomy, phylogeny, genetic diversity, epidemiology of the disease, and the role of vertebrate host in the perpetuation of rickettsioses in Africa. Our review also highlights some of the species of Rickettsia that are responsible for disease, the role of tick vectors (both hard and soft ticks) and the species of Rickettsia associated with diverse tick species across the continent. Additionally, this article emphasizes the evolutionary perspective of rickettsiae perpetuation and the possible role of amplifying vertebrate host and other small mammals, domestic animals and wildlife in the epidemiology of Rickettsia species. We also specifically, discussed the role of avian population in the epidemiology of SFG rickettsiae. Furthermore, we highlighted tick-borne rickettsioses among travelers due to African tick-bite fever (ATBF) and the challenges to surveillance of rickettsial infection, and research on rickettsiology in Africa. Our review canvasses the need for more rickettsiologists of African origin based within the continent to further research towards understanding the biology, characterization, and species distribution, including the competent tick vectors involved in their transmission of rickettsiae across the continent in collaboration with established researchers in western countries. We further highlighted the need for proper funding to encourage research despite competing demands for resources across the various sectors. We finalize by discussing the similarities between rickettsial diseases around the world and which steps need to be taken to help foster our understanding on the eco-epidemiology of rickettsioses by bridging the gap between the growing epidemiological data and the molecular characterization of Rickettsia species.

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“…sanguineus ticks collected from cattle and Rh. appendiculatus in sheep (83). The detection of this bacteriumin South Africa and in Rh.…”

Section: Southern Africamentioning

confidence: 98%

Unraveling the epidemiological relationship between ticks and rickettsial infection in Africa

Onyiche

Labruna²,

Saito³

2022

Front. Trop. Dis

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“…Several studies on ticks have been previously conducted in South Africa, which have shown that varieties of SFG are in circulation in the country 89,90 . Similarly, a recent study conducted by Essbauer et al 21 showed that different species of pathogenic Rickettsia are in circulation in the country.…”

Section: Domesticated Animalsmentioning

confidence: 99%

Evidence of pathogenic zoonotic tick-borne Rickettsia and Borrelia spp.  in some communal farms in the Eastern Cape Province, South Africa

Adelabu

Iweriebor

Okoh

et al. 2019

Preprint

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BackgroundThe abundance of tick populations in South Africa represents a probable risk for both animal and human health. Rickettsia and Borrelia are well-known significant agents of emerging human tick-borne infectious diseases throughout the world. Nevertheless, the epidemiology of their infections has been underreported in South Africa, Therefore, the aim of this study was to profile for zoonotic Rickettsia and Borrelia species from ticks infesting domesticated animals in the Eastern Cape, South Africa. Morphological and molecular identification techniques were conducted on 1,200 tick samples collected from domestic animals before screening for the target bacterial pathogens. ResultsThe molecular identification of the tick samples was based on the amplification of the 12S rRNA mitochondrial DNA while detection of Rickettsia and Borrelia species were carried out by amplifying fragments of gltA, ompA and ompB genes for Rickettsia and flaB gene for Borrelia spp. Thereafter, the positive ticks, Borrelia and Rickettsia ompB amplicons were sequenced and further analysed. Eight species of ticks belonging to three genera; Rhipicephalus, Amblyomma, and Haemaphysalis were identified. A total of 320 (27%) samples were confirmed positive for Rickettsia out of which 74 (23%) were positive for both ompA and ompB genes. Phylogenetic analysis of ompB revealed a high homology to rickettsial reference strains from GenBank, while there was no positive result for Borrelia. The generated sequences showed 99.1 to 100% homology with R. africae-KX227790 (100 %), R. parkeri - KY113111 (99.8 %), R .peacock (99.3 %) and R. slovaca - KJ675445, JX683122 (99.1 %) representative sequences in GenBank. ConclusionThe findings from this study revealed that ticks collected from domesticated animals were parasitized by Rickettsia species with possible zoonotic potential, which is detrimental to human health if bitten by infected ticks.

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“…Also, the populace living in proximity with domesticated animals, in the study area is at high risk of rickettsial infections, if bitten by infected ticks, as the presence of genetic materials of the organisms detected in this study indicates probable zoonotic potential, hence systematic study is further required to establish the detection of these pathogens from human samples. Eastern Cape32,90,91 followed by Rhipicephalus species33,92 . The detection of R. africae genetic material in A. hebraeum and Riphicephalis species in this study is corroborated by the findings of Yawa et al32 , thus confirming the role of A .hebraeum and Riphicephalis spp.…”

mentioning

confidence: 99%

Evidence of pathogenic zoonotic tick-borne Rickettsia and Borrelia spp. in some communal farms in the Eastern Cape Province, South Africa

Adelabu

Iweriebor

Okoh

et al. 2019

Preprint

Self Cite

View full text Add to dashboard Cite

The abundance of tick populations in South Africa represents a probable risk for both animal and human health. Rickettsia and Borrelia are well-known significant agents of emerging human tick-borne infectious diseases throughout the world. Nevertheless, the epidemiology of their infections has been underreported in South Africa, Therefore, the aim of this study was to profile for zoonotic Rickettsia and Borrelia species from ticks infesting domesticated animals in the Eastern Cape, South Africa. Morphological and molecular identification techniques were conducted on 1,200 tick samples collected from domestic animals before screening for the target bacterial pathogens. The molecular identification of the tick samples was based on the amplification of the 12S rRNA mitochondrial DNA while those of Rickettsia and Borrelia species were carried out by amplifying fragments of glt A, omp A and omp B genes for Rickettsia and fla B gene for Borrelia spp. Thereafter, the positive ticks, Borrelia and Rickettsia omp B amplicons were sequenced and further analysed. Eight species of ticks belonging to three genera; Rhipicephalus, Amblyomma, and Haemaphysalis were identified. A total of 320 (27%) samples were confirmed positive for Rickettsia out of which 74 (23%) were positive for both omp A and omp B genes. Phylogenetic analysis of omp B revealed a high homology to rickettsial reference strains from GenBank, while there was no positive result for Borrelia. The generated sequences showed 99.1 to 100% homology with R. africae -KX227790 (100%), R. parkeri - KY113111 (99.8%), R .peacock (99.3%) and R. slovaca - KJ675445, JX683122 (99.1%) representative sequences in GenBank. The findings from this study revealed that ticks collected from domesticated animals were parasitized by Rickettsia species with possible zoonotic potential, which is detrimental to human health if bitten by infected ticks.

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Molecular screening of ticks for the presence of Rickettsia species: A public health concern

Cited by 3 publications

References 55 publications

Unraveling the epidemiological relationship between ticks and rickettsial infection in Africa

Unraveling the epidemiological relationship between ticks and rickettsial infection in Africa

Evidence of pathogenic zoonotic tick-borne Rickettsia and Borrelia spp.  in some communal farms in the Eastern Cape Province, South Africa

Evidence of pathogenic zoonotic tick-borne Rickettsia and Borrelia spp. in some communal farms in the Eastern Cape Province, South Africa

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Molecular screening of ticks for the presence of Rickettsia species: A public health concern

Cited by 3 publications

References 55 publications

Unraveling the epidemiological relationship between ticks and rickettsial infection in Africa

Unraveling the epidemiological relationship between ticks and rickettsial infection in Africa

Evidence of pathogenic zoonotic tick-borne Rickettsia and Borrelia spp. &nbsp;in some communal farms in the Eastern Cape Province, South Africa

Evidence of pathogenic zoonotic tick-borne Rickettsia and Borrelia spp. in some communal farms in the Eastern Cape Province, South Africa

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Evidence of pathogenic zoonotic tick-borne Rickettsia and Borrelia spp. in some communal farms in the Eastern Cape Province, South Africa