Evaluation of Anaplasma phagocytophilum infection in experimentally inoculated sheep and determination of Anaplasma spp seroprevalence in 8 free-ranging sheep flocks in California and Oregon

Gorman, Jennifer K.; Hoar, Bruce R.; Nieto, Nathan C.; Foley, Janet E.

doi:10.2460/ajvr.73.7.1029

Cited by 10 publications

(5 citation statements)

References 26 publications

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“…and is therefore suitable to diagnose also antibodies against A. phagocytophilum [ 60 , 61 ]. Cross-reactivity between A. phagocytophilum and A. marginale was described with the IFAT and this probably also occurs with A. ovis [ 62 , 63 ]. Therefore, species distinction based on serology is impossible with these methods.…”

Section: Discussionmentioning

confidence: 99%

Anaplasma phagocytophilum and Anaplasma ovis–Emerging Pathogens in the German Sheep Population

et al. 2021

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Knowledge on the occurrence of pathogenic tick-borne bacteria Anaplasma phagocytophilum and Anaplasma ovis is scarce in sheep from Germany. In 2020, owners from five flocks reported ill thrift lambs and ewes with tick infestation. Out of 67 affected sheep, 55 animals were clinically examined and hematological values, blood chemistry and fecal examinations were performed to investigate the underlying disease causes. Serological tests (cELISA, IFAT) and qPCR were applied to all affected sheep to rule out A. phagocytophilum and A. ovis as a differential diagnosis. Ticks were collected from selected pastures and tested by qPCR. Most animals (n = 43) suffered from selenium deficiency and endoparasites were detected in each flock. Anaplasma spp. antibodies were determined in 59% of examined sheep. Seventeen animals tested positive for A. phagocytophilum by qPCR from all flocks and A. phagocytophilum was also detected in eight pools of Ixodes ricinus. Anaplasma phagocytophilum isolates from sheep and ticks were genotyped using three genes (16S rRNA, msp4 and groEL). Anaplasma ovis DNA was identified in six animals from one flock. Clinical, hematological and biochemical changes were not significantly associated with Anaplasma spp. infection. The 16S rRNA analysis revealed known variants of A. phagocytophilum, whereas the msp4 and groEL showed new genotypes. Further investigations are necessary to evaluate the dissemination and health impact of both pathogens in the German sheep population particularly in case of comorbidities.

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Section: Discussionmentioning

confidence: 99%

Anaplasma phagocytophilum and Anaplasma ovis–Emerging Pathogens in the German Sheep Population

et al. 2021

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“…A high detection rate was also reported from five sheep flocks (n = 156) in Hungary, with 99.4% seropositive animals [2] and from a sheep flock (n = 357) from Idaho (USA) with an antibody response to A. ovis of 94.8% [5]. In contrast, the presence of antibodies to Anaplasma species varied from 0% to 43.3% among eight sheep flocks in California and Oregon (USA) determined by cELISA and indirect immunofluorescence assay [6]. The mean antibody levels in sheep from the northern federal states (SH, LS) were significantly lower compared to the levels from sheep in the West (NRW) and the South (BW, BAV) of Germany.…”

Section: Occurrence Of Anaplasma Spp In German Small Ruminant Flocksmentioning

confidence: 66%

“…However, reports about the focal occurrence of A. ovis in Central European countries like Hungary, Slovakia and Germany are increasing [2][3][4]. Both pathogens are also present in the US sheep population, but detailed information about the dissemination is lacking [5,6].…”

Section: Introductionmentioning

confidence: 99%

Seroprevalence and Risk Factors of Anaplasma spp. in German Small Ruminant Flocks

Rubel

Schoneberg

Wolf

et al. 2021

Animals

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Knowledge about the distribution of Anaplasma spp. in small ruminants from Germany is limited. Therefore, serum samples were examined from 71 small ruminant flocks (2731 sheep, 447 goats) located in the five German federal states: Schleswig-Holstein (SH), Lower Saxony (LS), North Rhine-Westphalia (NRW), Baden-Wuerttemberg (BW) and Bavaria (BAV). Antibodies to Anaplasma spp. were determined by a cELISA based on the MSP5 antigen. A risk factor analysis at animal and flock level was also performed. Antibodies to Anaplasma spp. were detected in 70/71 flocks without significant difference in the intra-flock prevalence (IFP) between the federal states. The mean antibody levels from sheep were significantly lower in northern Germany (LS, SH) compared to west (NRW) and south Germany (BW, BAV). Sheep had a 2.5-fold higher risk of being seropositive than goats. Females and older animals (>2 years) were more likely to have antibodies to Anaplasma spp. in one third and one quarter of cases, respectively. Flocks used for landscape conservation had a five times higher risk of acquiring an IFP greater than 20%. Cats and dogs on the farms increased the probability for small ruminant flocks to have an IFP of above 20% 10-fold and 166-fold, respectively. Further studies are necessary to assess the impact of Anaplasma species on the health of small ruminants in Germany.

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“…Despite this reorganization, phenotypic and preliminary genetic data strongly support the presence of multiple distinct strains. For example, strains in Europe commonly cause clinical disease in small hoofstock, but North American strains are neither particularly infectious nor virulent based on data from experimental infections of sheep or cattle (Pusterla et al, 1997; Stuen, 2007; Gorman et al, 2012). Similarly, in England, 2 genetically distinct subpopulations of A. phagocytophilum coexist in separate enzootic cycles, one involving deer and I. ricinus ticks and the other involving field voles and I. trianguliceps (Bown et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Unique strains of Anaplasma phagocytophilum segregate among diverse questing and non-questing Ixodes tick species in the western United States

Rejmanek

Freycon

Bradburd

et al. 2013

Ticks and Tick-borne Diseases

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The emerging tick-borne pathogen Anaplasma phagocytophilum infects humans, domestic animals, and wildlife throughout the Holarctic. In the western U.S., the ecology of A. phagocytophilum is particularly complex, with multiple pathogen strains, tick vectors, and reservoir hosts. A recent phylogenetic analysis of A. phagocytophilum strains isolated from various small mammal hosts in California documented distinct clustering of woodrat strains separate from sciurid (chipmunk and squirrel) strains. Here, we identified strains of A. phagocytophilum in various Ixodes tick species in California and related these genotypes to those found among reservoir and clinical hosts from the same areas. The sequences from all of the nidicolous (nest-dwelling) Ixodes ticks grouped within a clade that also contained all of the woodrat-origin A. phagocytophilum strains. Two of the I. pacificus sequences were also grouped within this woodrat clade, while the remaining five belonged to a less genetically diverse clade that included several sciurid-origin strains as well as a dog, a horse, and a human strain. By comparing A. phagocytophilum strains from multiple sources concurrently, we were able to gain a clearer picture of how A. phagocytophilum strains in the western U.S. are partitioned, which hosts and vectors are most likely to be infected with a particular strain, and which tick species and reservoir hosts pose the greatest health risk to humans and domestic animals.

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Evaluation of Anaplasma phagocytophilum infection in experimentally inoculated sheep and determination of Anaplasma spp seroprevalence in 8 free-ranging sheep flocks in California and Oregon

Abstract: Infection with A phagocytophilum in mature sheep generally resulted in subclinical disease. Higher Anaplasma spp seroprevalence in sheep in the Sierra Nevada foothills corresponded to the geographic distribution of anaplasmosis reported for dogs, horses, and humans.

Cited by 10 publications

References 26 publications

Anaplasma phagocytophilum and Anaplasma ovis–Emerging Pathogens in the German Sheep Population

Anaplasma phagocytophilum and Anaplasma ovis–Emerging Pathogens in the German Sheep Population

Seroprevalence and Risk Factors of Anaplasma spp. in German Small Ruminant Flocks

Unique strains of Anaplasma phagocytophilum segregate among diverse questing and non-questing Ixodes tick species in the western United States

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