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

Abstract

A B S T R A C TDespite close association between camels and humans, molecular based studies on vector-borne pathogens infecting camels are scarce compared to other animals in Iran. The current study was carried out to investigate the occurrence of vector-borne bacteria in the blood of dromedaries by molecular tools. A total of 200 peripheral blood samples were collected from apparently healthy animals. Microscopic examination was performed on Giemsa-stained blood smears, and drops of blood were spotted on Whatman FTA ® cards for molecular analyses. Genomic DNA was extracted from the cards, and PCR amplification followed by sequencing of positive samples was carried out for the detection of Anaplasmataceae, spotted fever group (SFG) rickettsiae, Bartonella spp. and Borrelia spp. Intra-cytic forms of any blood pathogens could not be detected by light microscopy. PCR results revealed 30 animals (15%) to be infected with Anaplasmataceae bacteria. Analyses of sequences revealed a strain of Anaplasma sp. identical to Candidatus Anaplasma camelii isolated from camels, cattle and deer in Asia and Africa. Neither SFG rickettsiae, nor Borrelia or Bartonella species were found. Further studies for determining epidemiological role of camels and its zoonotic potential are recommended. This paper reviews the current knowledge on camels' tickborne bacteria including microscopy, serology and molecular studies.confirmed by DNA sequencing in camels are Candidatus Anaplasma camelii (genetically close to A. platys), A. phagocytophilum and A. ovis [10][11][12][13][14][15][16][17][18]. Clinical signs of natural infections are described as fever, pale and icteric conjunctiva suggestive of anaemia, dullness, anorexia, diarrhoea, loss of appetite, emaciation, coughing, lacrimation, rough hair coat, abortion, and/or infertility [7,19]. Intramuscular administration of oxytetracycline at 20 mg/kg as specific therapy and injectable B-complex, iron, folic acid and hydroxycobalamin as supportive therapy is the recommended therapeutic regimen [7,19]. Infection with and antibodies against several species of Rickettsia [20,21], as well as infection with Bartonella [22] and Borrelia [23,24] have been also documented.According to official estimates, around 183,900 camels live in Iran [25]. Given the growing scientific and public health interest in camels, we investigated the occurrence of selected vector-borne bacteria;https://doi.

Ticks and associated pathogens in camels (Camelus dromedarius) from Riyadh Province, Saudi Arabia

“…However, these results do not allow drawing any definitive conclusions about the occurrence of those pathogens in the sampled population, also considering the temporary nature of parasitemia in the blood of infected animals. To date, DNA of Theileria equi, T. annulata, T. mutans, T. ovis and B. caballi have been detected in blood of dromedaries [18,[52][53][54][55]. There is limited knowledge on piroplasms specific for camels and due to lack of experimental infections and molecular characterisation, the taxonomic status of some species such as Theileria camelensis [56], Theileria dromedarii [57], Theileria assiutis [58] and Babesia cameli [59] remain unresolved.…”

“…Although genus Anaplasma includes six recognized species, A. phagocytophilum is the major zoonotic pathogen [16]. Apart from humans, A. phagocytophilum has been detected in dogs, horses, cats, sheep, goats, cattle and camels [17,18]. In addition, three new possible Anaplasma species, Anaplasma odocoilei [19], Anaplasma capra [20] and "Candidatus Anaplasma camelii" [21] have recently been reported from deer, goats and camels, respectively.…”

Ticks and associated pathogens in camels (Camelus dromedarius) from Riyadh province, Saudi Arabia

“…The other two species herein identified in camels, H. impeltatum and H. excavatum, usually parasitize cattle and sheep [8,51] and their finding in camels might be due to the husbandry practices in desert areas where all livestock share common inhabitancy, wandering in nature searching for water sources and grazing land. caballi have been detected in blood of dromedaries [18,[52][53][54][55]. There is limited knowledge on piroplasms specific for camels and due to lack of experimental infections and molecular characterisation, the taxonomic status of some species such as Theileria camelensis [56], Theileria dromedarii [57], Theileria assiutis [58] and Babesia cameli [59] remain unresolved.…”

Ticks and associated pathogens in camels (Camelus dromedarius) from Riyadh province, Saudi Arabia

“…Though genus Anaplasma includes six recognized species, A. phagocytophilum is the major zoonotic pathogen [16]. Apart from humans, A. phagocytophilum has been detected in dogs, horses, cats, sheep, goats, cattle and camels [17,18]. In addition, three new possible Anaplasma species, Anaplasma odocoilei [19], Anaplasma capra [20] and Candidatus Anaplasma camelii [21] have recently been reported from deer, goats and camels, respectively.…”

“…To date DNA of Theileria equi, T. annulata, T. mutans, T. ovis and Babesia caballi have been detected in blood of dromedaries[18,[50][51][52][53]. There is shortage of knowledge on piroplasms specific for camels and due to lack of experimental infections and molecular characterisation, the taxonomic status of some species such as Theileria camelensis[54], Theileria dromedarii [55], Theileria assiutis[56] and Babesia cameli[57] remain unresolved.…”