Ornithodoros savignyi, the Tick Vector of “Candidatus Borrelia kalaharica” in Nigeria

Cutler, Sally J.; Idris, Jibrin Manu; Ahmed, Akeem Olayiwola; Elelu, Nusirat

doi:10.1128/jcm.00532-18

Cited by 9 publications

(13 citation statements)

References 32 publications

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“…There has been significant increase in the annual temperature of Saudi Arabia over the last few decades [ 79 , 80 ]. Higher temperatures directly influence the transmission efficiency of a vector to a vertebrate host [ 70 , 71 ] and result in closer proximity of the vectors to animal housing and potential exposure to humans [ 81 ].…”

Section: Geographical Aspects Contributing To Virus Spreadmentioning

confidence: 99%

Kyasanur Forest Disease and Alkhurma Hemorrhagic Fever Virus—Two Neglected Zoonotic Pathogens

2020

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Kyasanur Forest disease virus (KFDV) and Alkhurma hemorrhagic fever virus (AHFV) are tick-borne flaviviruses that cause life-threatening hemorrhagic fever in humans with case fatality rates of 3–5% for KFDV and 1–20% for AHFV, respectively. Both viruses are biosafety level 4 pathogens due to the severity of disease they cause and the lack of effective countermeasures. KFDV was discovered in India and is restricted to parts of the Indian subcontinent, whereas AHFV has been found in Saudi Arabia and Egypt. In recent years, both viruses have spread beyond their original endemic zones and the potential of AHFV to spread through ticks on migratory birds is a public health concern. While there is a vaccine with limited efficacy for KFDV used in India, there is no vaccine for AHFV nor are there any therapeutic concepts to combat infections with these viruses. In this review, we summarize the current knowledge about pathogenesis, vector distribution, virus spread, and infection control. We aim to bring attention to the potential public health threats posed by KFDV and AHFV and highlight the urgent need for the development of effective countermeasures.

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Section: Geographical Aspects Contributing To Virus Spreadmentioning

confidence: 99%

Kyasanur Forest Disease and Alkhurma Hemorrhagic Fever Virus—Two Neglected Zoonotic Pathogens

2020

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“…Homogenized ticks were resuspended in proteinase K and lysis buffer at a volume of 1:10 (20 μL in 180 μL for the bigger ticks and 10 μL in 90 μL for smaller ticks) respectively for each sample. Ticks were incubated overnight in the water bath at 56 °C as previously described [ 25 , 30 ].…”

Section: Methodsmentioning

confidence: 99%

“…A final PCR volume of 25 μL containing reaction buffer (1X), dNTPs (0.2 mM each), MgCl 2 2.5 mM), 2 μL DNA template, each primer at (500 mM), probe (250 mM), and 0.15U taq polymerase. Cycling conditions were as follows: 95 °C for 10 min, 40 cycles of 95 °C for 15 s, and 60 °C for 1 min as previously described [ 25 ]. DNA of B. burgdoferi senso stricto B31 strain was used as positive control and nuclease-free water (Invitrogen) as negative control.…”

Section: Methodsmentioning

confidence: 99%

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Comparative Analysis of Tick-Borne Relapsing Fever Spirochaetes from Ethiopia and Nigeria

et al. 2023

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Despite increasing reports of tick-borne diseases in Africa, remarkably, reports of tick-borne relapsing fever (TBRF) in Nigeria are lacking. Ornithodoros savignyi from Nigeria have been reported with the relapsing fever Candidatus Borrelia kalaharica. Conversely, in Ethiopia, the agent of relapsing fever is the louse-borne relapsing fever (LBRF) spirochaete Borrelia recurrentis with no TBRF reported to occur. A total of 389 Ornithodoros ticks, Ethiopia (N = 312) and Nigeria (N = 77), were sampled, together with 350 cattle, and 200 goat sera were collected from Nigeria. Samples were screened for Borrelia spp. by RT-PCR. Reactive samples were confirmed, then sequenced using flagellin B, 16S rRNA, and 16S–23S intergenic spacer region. The prevalence of Borrelia spp. in livestock was 3.8% (21/550) and 14% (3/21) after final molecular confirmation. Of 312 ticks from Ethiopia, 3.5% (11/312) were positive for Borrelia, with 36% (4/11) by conventional PCR. Sequencing revealed that the borreliae in soft ticks was C. B. kalaharica, whilst that found in animals was Borrelia theileri. Soft ticks were confirmed by sequencing 7% (22/312) and 12% (9/77) of the Ethiopian and Nigerian ticks, respectively. Phylogenetic analysis revealed that these were Ornithodoros savignyi. This is the first evidence of C. B. kalaharica in Ethiopia and demonstrates the co-existence of TBRF in a country endemic to LBRF. Important, this might cause a diagnostic challenge given that LBRF is predominantly diagnosed by microscopy, which cannot differentiate these two spirochaetes. Furthermore, we report B. theileri in ruminants in Nigeria, which may also be of veterinary and economic importance.

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“…Most RF cases in the US are caused by Borrelia hermsii and transmitted by Ornithodoros hermsi soft ticks, which typically live in nests of rodents such as ground squirrels, tree squirrels, and chipmunks in coniferous forests at altitudes between a 500 and 2500 m. Soft ticks can acquire RF Borrelia by feeding on infected rodents, the reservoir hosts. Once infected, soft ticks are infectious for life [ 44 ].…”

Section: Endemic Relapsing Fever Borreliosis (Stbrf)mentioning

confidence: 99%

Borreliae Part 2: Borrelia Relapsing Fever Group and Unclassified Borrelia

Trevisan

Cinco

Trevisini

et al. 2021

Biology

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Borreliae of the relapsing fever group (RFG) are heterogenous and can be divided mainly into three groups according to vectors, namely the soft-tick-borne relapsing fever (STBRF) Borreliae, the hard-tick-borne relapsing fever (HTBRF) Borreliae, the louse-borne relapsing fever (LBRF) Borreliae, and the avian relapsing fever ones. With respect to the geographical distribution, the STBRF Borreliae are further subdivided into Old World and New World strains. Except for the Avian relapsing fever group Borreliae, which cause avian spirochetosis, all the others share infectivity in humans. They are indeed the etiological agent of both endemic and epidemic forms of relapsing fever, causing high spirochaetemia and fever. Vectors are primarily soft ticks of Ornithodoros spp. in the STBRF group; hard ticks, notably Ixodes sp., Amblyomma sp., Dermacentor sp., and Rhipicephalus sp., in the HTBRF group; and the louse pediculus humanus humanus in the TBRF one. A recent hypothesis was supported for a common ancestor of RFG Borreliae, transmitted at the beginning by hard-body ticks. Accordingly, STBRF Borreliae switched to use soft-bodied ticks as a vector, which was followed by the use of lice by Borrelia recurrentis. There are also new candidate species of Borreliae, at present unclassified, which are also described in this review.

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Ornithodoros savignyi, the Tick Vector of “Candidatus Borrelia kalaharica” in Nigeria

Cited by 9 publications

References 32 publications

Kyasanur Forest Disease and Alkhurma Hemorrhagic Fever Virus—Two Neglected Zoonotic Pathogens

Kyasanur Forest Disease and Alkhurma Hemorrhagic Fever Virus—Two Neglected Zoonotic Pathogens

Comparative Analysis of Tick-Borne Relapsing Fever Spirochaetes from Ethiopia and Nigeria

Borreliae Part 2: Borrelia Relapsing Fever Group and Unclassified Borrelia

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