Survey of Serum Amyloid A and Bacterial and Viral Frequency Using qPCR Levels in Recently Captured Feral Donkeys from Death Valley National Park (California)

Abstract

Feral donkey removal from state land has raised concerns in terms of disease transmission between equine species. Disease outbreaks may occur as a result of the relocation of animals to new environments. Virus and bacteria DNA load and serum amyloid A derived from the pathogenic processes that they involve were measured in recently captured donkeys. Blood and nasal swabs were collected from 85 donkeys (Death Valley National Park, Shoshone, California); 24 were retested after 30/60 days in the Scenic (Arizona) long-term holding facility co-mingled with feral donkeys from Arizona and Utah. Quantitative Real-Time PCR (qPCR) was performed to detect viral and bacterial genomic material (equine influenza A [EIV], equine rhinitis A and B viruses, AHV-2, AHV-3, AHV-5 and EHV-1, EHV-4, Streptococcus equi subspecies equi and zooepidemicus,). Significant relations between behavior, body condition score, nasal discharge, and coughing were found in donkeys for which AHV-2 and Streptococcus zooepidemicus DNA was detected. Higher SAA concentrations were found in foals. AHV-2 and Streptococcus zooepidemicus DNA concentrations significantly differed between sampling moments (p < 0.05). In conclusion, donkeys do not appear to be a substantial risk for disease transmission to horses but could be if they carried strangles or other processes in which AHV-2 and Streptococcus zooepidemicus were involved.

Detection and Molecular Characterization of Two Gammaherpesviruses from Pantesco Breed Donkeys during an Outbreak of Mild Respiratory Disease

“…Over the years, asinine GHVs have been predominantly reported in donkeys, but they have also been detected in healthy horses and mules [ 2 , 5 , 27 , 28 , 29 ] and in donkeys and horses showing respiratory [ 11 , 17 , 27 , 28 , 30 , 31 , 32 ], neurological [ 12 ], and abortive [ 13 ] signs. However, the evidence of GHV infection in healthy equids makes their role as pathogens questionable.…”

“…Similarly, a higher prevalence of EqGHV-2 and EqGHV-5 was observed in horses with airway inflammation compared to clinical healthy horses [ 34 ], and the occurrence of GHV infection in healthy equids is less common compared to the prevalence of EqGHV2 and EqGHV5 in symptomatic equids [ 2 , 11 , 17 ]. More recently, the relationship between stress and nasal discharge, an increase of viral excretion, and a recrudescence of herpesviral latent infections in feral donkeys or captive Grévy’s zebras was suggested [ 32 , 35 ]. It is therefore possible that in our case, a respiratory infection caused herpesviral reactivation.…”

A Pilot Serosurvey for Selected Pathogens in Feral Donkeys (Equus asinus)

“…A limitation of this testing is the specificity for EHV-1; while infection with asinine herpesvirus 3 (EHV-8) or EHV-9 might generate cross-reactive antibodies based on homology to the target antigen in the EHV-1 assay, evidence of infection with other herpesvirus strains, including EHV-4, might not be detected. However, asinine herpesvirus 2, 3, and 5 were detected in nasal swabs using qPCR in this population of donkeys [ 7 ]. Numerous vaccines are commercially available to protect horses and other equids from EHV-1 infection, including killed virus vaccines, a live virus vaccine, and formulations approved for use during pregnancy to prevent abortion, although there are no current vaccine claims to protect against the neurologic form of disease [ 25 ].…”

“…The comparison serologic data in this study were not sorted in any way to account for these limitations. In addition, this study is not a comprehensive serologic survey of all possible equid pathogens; however, the results of this study and one other study do indicate that these wild equid populations may be extremely naïve and susceptible to many common pathogens upon removal from the wild, and there appears to be an increase in pathogen detection upon introduction to long-term holding facilities [ 7 ].…”

“…Nasal samples were taken from this same population of donkeys to detect viral and bacterial pathogen levels using quantitative real-time PCR (qPCR). The study found little evidence of EHV1, 4, EIV, or Streptococcus equi subspecies equi , but the samples did contain DNA from asinine herpes virus 2, 3, and 5 and Streptococcus equi subspecies zooepidemicus [ 7 ].…”