Serological and Molecular Detection of Anaplasma spp. in Blood From Healthy Horses: A Preliminary Study of Horses in East Texas

Russell, Alyssa B.; Shost, Nichola; Burch, Megan; Salazara, Luis Lopez; Fikes, K.; Bechelli, Jeremy; Suagee-Bedore, J.K.

doi:10.1016/j.jevs.2021.103757

Cited by 2 publications

(1 citation statement)

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“…In a recent study of horses with suspected tick‐borne illness in Pennsylvania, only 41.3% of horses had positive A. phagocytophilum antibody titers (≥1:50) on IFA assay 10 . Seropositivity rates as high as 100% have been reported in apparently healthy horses from central New York and western New Jersey 16 . Antibody response to acute infection with A. phagocytophilum in the horse takes several weeks, 17 and the lower seropositivity rate in clinically affected horses could represent a risk factor for development of clinical EGA.…”

Section: Discussionmentioning

confidence: 99%

Transfer of naturally acquired specific passive immunity against Anaplasma phagocytophilum in foals in Southeastern Pennsylvania and Northern Maryland

Rule

Boyle

Stefanovski

et al. 2023

Veterinary Internal Medicne

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BackgroundEquine granulocytic anaplasmosis (EGA) is a common disease in adult horses, but clinical disease in foals is rarely reported. The relationship between equine maternal and neonatal antibodies to Anaplasma phagocytophilum is unclear.Hypothesis/ObjectivesThat mares in an endemic region would be seropositive for A. phagocytophilum and that mare and foal serum IgG concentrations for A. phagocytophilum would correlate. Additionally, we hypothesized that foal IgG concentrations for A. phagocytophilum acquired by passive immunity would decline by 6 months of age.AnimalsTwenty‐two healthy mare‐foal pairs.MethodsThis prospective observational study investigated serum IgG concentrations specific for A. phagocytophilum in mares and foals using an immunofluorescent antibody test (IFA). The association between foal titer (as a binary variable) and age in months was assessed using a mixed‐effects logistic regression.ResultsA positive correlation between newborn foal antibody titers and mare titers was identified at both the pre‐foaling (τa = 0.38, τb = 0.50, P = .009) and foaling timepoints (τa = 0.36, τb = 0.47, P = .01). In A. phagocytophilum seropositive neonates, it was unlikely that a positive titer would be detected by 3 months of age (OR = 0.002, P = .02, 95% CI: 0.00001‐0.38). Three out of 20 foals seroconverted between 3 and 6 months of age.Conclusions and Clinical ImportanceTransfer of specific passive immunity to A. phagocytophilum occurred in 80% of foals born to seropositive mares and declined by 3 months of age. A. phagocytophilum infection should be considered in foals displaying clinical signs consistent with EGA.

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Section: Discussionmentioning

confidence: 99%