Epidemiology and genetic characteristics of tick-borne bacteria in dromedary camels of the world

Selmi, Rachid; Belkahia, Hanène; Sazmand, Alireza; Saïd, Mourad Ben; Messadi, Lilia

doi:10.1016/j.actatropica.2022.106599

Cited by 12 publications

(5 citation statements)

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“…Further, in Ben Said et al (2013 found 29% of tested camels to be seropositive for A. phagocytophilum. Though it remains unknown if camels are definitive or reservoir hosts of A. phagocytophilum (Selmi, 2022) or whether the strains found in camels are also pathogenic, our findings strongly support the epidemiological role of camels in their spread and emergence.…”

Section: Discussionsupporting

confidence: 71%

Tissue-specific localization of tick-borne pathogens in ticks collected from camels in Kenya: insights into vector competence

Khogali,

Bastos,

Bargul

et al. 2024

Front. Cell. Infect. Microbiol.

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BackgroundTick-borne pathogen (TBP) surveillance studies often use whole-tick homogenates when inferring tick-pathogen associations. However, localized TBP infections within tick tissues (saliva, hemolymph, salivary glands, and midgut) can inform pathogen transmission mechanisms and are key to disentangling pathogen detection from vector competence.MethodsWe screened 278 camel blood samples and 504 tick tissue samples derived from 126 camel ticks sampled in two Kenyan counties (Laikipia and Marsabit) for Anaplasma, Ehrlichia, Coxiella, Rickettsia, Theileria, and Babesia by PCR-HRM analysis.ResultsCandidatus Anaplasma camelii infections were common in camels (91%), but absent in all samples from Rhipicephalus pulchellus, Amblyomma gemma, Hyalomma dromedarii, and Hyalomma rufipes ticks. We detected Ehrlichia ruminantium in all tissues of the four tick species, but Rickettsia aeschlimannii was only found in Hy. rufipes (all tissues). Rickettsia africae was highest in Am. gemma (62.5%), mainly in the hemolymph (45%) and less frequently in the midgut (27.5%) and lowest in Rh. pulchellus (29.4%), where midgut and hemolymph detection rates were 17.6% and 11.8%, respectively. Similarly, in Hy. dromedarii, R. africae was mainly detected in the midgut (41.7%) but was absent in the hemolymph. Rickettsia africae was not detected in Hy. rufipes. No Coxiella, Theileria, or Babesia spp. were detected in this study.ConclusionsThe tissue-specific localization of R. africae, found mainly in the hemolymph of Am. gemma, is congruent with the role of this tick species as its transmission vector. Thus, occurrence of TBPs in the hemolymph could serve as a predictor of vector competence of TBP transmission, especially in comparison to detection rates in the midgut, from which they must cross tissue barriers to effectively replicate and disseminate across tick tissues. Further studies should focus on exploring the distribution of TBPs within tick tissues to enhance knowledge of TBP epidemiology and to distinguish competent vectors from dead-end hosts.

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Section: Discussionsupporting

confidence: 71%

Tissue-specific localization of tick-borne pathogens in ticks collected from camels in Kenya: insights into vector competence

Khogali,

Bastos,

Bargul

et al. 2024

Front. Cell. Infect. Microbiol.

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“…The authors suggested that this was because of the common practice of keeping camels together with other ruminants in the same shelter in arid and semiarid regions [ 111 ]. Since the platelets of the camels in the aforementioned studies were not infected [ 103 , 111 ], it has been recommended that further research through in vitro culture and experimental studies are required to understand the paradox of A. platys -like infection in camels [ 112 ]. In north Tunisia, an A. platys -like organism was detected in 3.5% of cattle, 11% sheep and 22.8% of goats using heminested groEL PCR, RFLP assay and sequencing [ 113 ].…”

Section: Molecular Epidemiology and Genetic Diversity Of An...mentioning

confidence: 99%

Anaplasma Species in Africa—A Century of Discovery: A Review on Molecular Epidemiology, Genetic Diversity, and Control

Kolo

2023

Pathogens

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Anaplasma species, belonging to the family Anaplasmataceae in the order Rickettsiales, are obligate intracellular bacteria responsible for various tick-borne diseases of veterinary and human significance worldwide. With advancements in molecular techniques, seven formal species of Anaplasma and numerous unclassified species have been described. In Africa, several Anaplasma species and strains have been identified in different animals and tick species. This review aims to provide an overview of the current understanding of the molecular epidemiology and genetic diversity of classified and unclassified Anaplasma species detected in animals and ticks across Africa. The review also covers control measures that have been taken to prevent anaplasmosis transmission on the continent. This information is critical when developing anaplasmosis management and control programs in Africa.

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“…A plethora of Bartonella species, with multiple genotypes and ‘ Candidatus ’ species, have been reported in domestic ruminants and dromedary worldwide (Dahmani et al., 2017; Gonçalves et al., 2020; Selmi et al., 2022), namely B. bovis , Bartonella chomelii , B. henselae , Bartonella schoenbuchensis , Bartonella capreoli , B. melophagi , ‘ Candidatus B. davousti’, and ‘ Candidatus B. dromedarii’ (Boularias et al., 2020; Ereqat et al., 2016; Gonçalves et al., 2020; Selmi et al., 2020). These infections can vary in clinical presentation, with some cases associated with endocarditis while others remain asymptomatic (Maillard et al., 2007).…”

Section: Introductionmentioning

confidence: 99%

“…Recent studies have provided additional evidence regarding ticks' involvement in Bartonella transmission. Specifically, a mounting body of evidence supports the transovarial and transstadial transmission of bartonellae within ixodid ticks (e.g., Rhipicephalus sanguineus sensu lato) (Selmi et al., 2022; Wechtaisong et al., 2021).…”

Section: Introductionmentioning

confidence: 99%

Bartonella species in dromedaries and ruminants from Lower Shabelle and Benadir regions, Somalia

Osman,

Hassan‐Kadle,

Dias

et al. 2024

Zoonoses and Public Health

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BackgroundBartonellosis, caused by bacteria of the genus Bartonella, is a zoonotic disease with several mammalian reservoir hosts. In Somalia, a country heavily reliant on livestock, zoonotic diseases pose significant public health and economic challenges. To the best of our knowledge, no study has been performed aiming to verify the occurrence of Bartonella spp. in Somalia. This study investigated the occurrence and molecular characterization of Bartonella in dromedary (Camelus dromedarius, Linnaeus, 1758), cattle, sheep, and goats from Somalia.Materials and Methods530 blood samples were collected from various animals (155 dromedary, 199 goat, 131 cattle, and 45 sheep) in Benadir and Lower Shabelle regions. DNA was extracted for molecular analysis, and a qPCR assay targeting the NADH dehydrogenase gamma subunit (nuoG) gene was used for Bartonella screening. Positive samples were also subjected to PCR assays targeting seven molecular markers including: nuoG, citrate synthase gene (gltA), RNA polymerase beta‐subunit gene (rpoB), riboflavin synthase gene (ribC), 60 kDa heat‐shock protein gene (groEL), cell division protein gene (ftsZ), and pap31 and qPCR targeting the 16‐23S rRNA internal transcribed spacer (ITS) followed by Sanger sequencing, BLASTn and phylogenetic analysis.ResultsOut of 530 tested animals, 5.1% were positive for Bartonella spp. by the nuoG qPCR assay. Goats showed the highest Bartonella occurrence (17/199, 8.5%), followed by sheep (6/44, 6.8%), cattle (4/131, 3.1%), and dromedary (1/155, 1.9%). Goats, sheep, and cattle had higher odds of infection compared to dromedary. Among nuoG qPCR‐positive samples, 11.1%, 14.8%, 11.1%, and 25.9% were positive in PCR assays based on nuoG, gltA, and pap31 genes, and in the qPCR based on the ITS region, respectively. On the other hand, nuoG qPCR‐positive samples were negative in the PCR assays targeting the ribC, rpoB, ftsZ, and groEL genes. While Bartonella bovis sequences were detected in cattle (nuoG and ITS) and goats (gltA), Bartonella henselae ITS sequences were detected in dromedary, goat, and sheep. Phylogenetic analysis placed gltA Bartonella sequence from a goat in the same clade of B. bovis.ConclusionThe present study showed, for the first time, molecular evidence of Bartonella spp. in dromedary and ruminants from Somalia and B. henselae in sheep and goats globally. These findings contribute valuable insights into Bartonella spp. occurrence in Somali livestock, highlighting the need for comprehensive surveillance and control measures under the One Health approach.

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Epidemiology and genetic characteristics of tick-borne bacteria in dromedary camels of the world

Cited by 12 publications

References 106 publications

Tissue-specific localization of tick-borne pathogens in ticks collected from camels in Kenya: insights into vector competence

Tissue-specific localization of tick-borne pathogens in ticks collected from camels in Kenya: insights into vector competence

Anaplasma Species in Africa—A Century of Discovery: A Review on Molecular Epidemiology, Genetic Diversity, and Control

Bartonella species in dromedaries and ruminants from Lower Shabelle and Benadir regions, Somalia

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