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A comparative study of single Theileria lestoquardi and mixed infections with Theileria ovis.
Al-Hamidhi, Salama; Elshafie, Elshafie I; Yaghfoori, Saeed; Morrison, W Ivan; Johnson, Eugene H; Babiker, Hamza A.
Afiliación
  • Al-Hamidhi S; Department of Biochemistry, College of Medicine and Health Sciences, Sultan Qaboos University, AlKhoud 123, PO Box 35, Muscat, Oman.
  • Elshafie EI; Department of Animal and Veterinary Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Muscat, Oman.
  • Yaghfoori S; Central Veterinary Research Laboratories, Al Amarat, P.O. Box 8067, Khartoum, Sudan.
  • Morrison WI; Laboratory for Hormozgan Veterinary, Bandar Abbas, Iran.
  • Johnson EH; Division of Infection and Immunity, The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK.
  • Babiker HA; Department of Animal and Veterinary Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Muscat, Oman.
Parasit Vectors ; 14(1): 370, 2021 Jul 20.
Article en En | MEDLINE | ID: mdl-34284816
ABSTRACT

BACKGROUND:

Epidemiological surveys in Oman have revealed a high prevalence of the co-occurrence of the pathogenic Theileria lestoquardi and the non-pathogenic Theileria ovis among sheep in the Barka region, Oman. Our most recent data illustrated an interaction and reduced mortality risk in animals co-infected with T. lestoquardi and T. ovis, suggesting that the latter confers protection against pathogenicity of T. lestoquardi. The present study extends the above findings and examines disease outcomes; clinical markers, hematological parameters, and parasite density in mixed and single T. lestoquardi infections.

METHODS:

A total of 390 blood samples were collected from 16 sheep pens located in Barka, Oman between July and November 2019. Theileria spp. were detected and quantified using qPCR assay targeting 18S rRNA, and the extent of genetic diversity was estimated by a panel of T. lestoquardi specific micro- and mini-satellites. The association of some disease markers with the presence of Theileria spp. and genetic diversity was tested.

RESULTS:

Theileria spp. were detected in 75 (19.2%) sheep; of these 65 (86.7%) had mixed infections (T. lestoquardi plus T. ovis), 8 (10.6%) were infected with T. lestoquardi alone, and 2 (2.7%) with only T. ovis. Exotic breeds had a higher risk for Theileria spp. infection. The density (18S rRNA gene copies) of both parasites was higher in single infection against mixed infection, and there was a relatively lower density of T. lestoquardi in mixed infections. However, there was no difference in hematological indices between single T. lestoquardi and mixed infections. High genetic diversity was observed among T. lestoquardi in Barka, with no differences of T. lestoquardi in single and mixed infections. The extent of diversity seen in Barka was higher (He = 0.772) than that reported in Oman in 2019 (He = 0.582), with distinct T. lestoquardi genotypes.

CONCLUSION:

The lower density of T. lestoquardi as mixed infection with T. ovis compared to single infection supports the hypothesis that T. ovis confers protection against lethal T. lestoquardi infection. However, there were no differences in disease correlations (clinical markers, hematological parameters, and density of parasites) or the extent of diversity of T. lestoquardi between the two types of infection. The presence of distinct T. lestoquardi genotypes in Barka, compared to that reported earlier in Oman, likely reflects movement of carrier animals and highlights the need for further analysis of the parasite populations to inform novel approaches for controlling malignant ovine theileriosis.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Contexto en salud: 3_ND Problema de salud: 3_zoonosis Asunto principal: Enfermedades de las Ovejas / Theileriosis / Variación Genética / Ovinos / Theileria Tipo de estudio: Observational_studies / Prevalence_studies / Risk_factors_studies Límite: Animals País/Región como asunto: Asia Idioma: En Revista: Parasit Vectors Año: 2021 Tipo del documento: Article País de afiliación: Omán

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Contexto en salud: 3_ND Problema de salud: 3_zoonosis Asunto principal: Enfermedades de las Ovejas / Theileriosis / Variación Genética / Ovinos / Theileria Tipo de estudio: Observational_studies / Prevalence_studies / Risk_factors_studies Límite: Animals País/Región como asunto: Asia Idioma: En Revista: Parasit Vectors Año: 2021 Tipo del documento: Article País de afiliación: Omán
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