Infectious disease surveillance of apparently healthy horses at a multi-day show using a novel nanoscale real-time PCR panel

Abstract

In the United States, horses are used for a variety of purposes including recreation, exhibition, and racing. As farm, performance, and companion animals, horses are a unique species from a zoonotic disease risk perspective, and the risks of subclinical infections spreading among horses can pose challenges. Using a nanoscale real-time PCR platform, we investigated the prevalence of 14 enteric pathogens, 11 Escherichia coli genes, and 9 respiratory pathogens in fecal samples from 97 apparently healthy horses at a multi-day horse event. In addition, sugar flotation test was performed for fecal parasites. E. coli f17 was commonly detected, prevalent in 59% of horses, followed closely by Streptococcus equi subsp. zooepidemicus (55%). Additional pathogens recognized included betacoronavirus, Campylobacter jejuni, Cryptosporidium sp., E. coli O157, equine adenovirus 1, equine rhinitis B virus, and others. The use of PCR data may overestimate the true prevalence of these pathogens but provides a sensitive overview of common pathogens present in healthy horses. Our results prompt the continued need for practical biosecurity measures at horse shows, both to protect individuals interacting with these horses and to minimize transmission among horses.

Frequency of Detection of Respiratory Pathogens in Clinically Healthy Show Horses Following a Multi-County Outbreak of Equine Herpesvirus-1 Myeloencephalopathy in California

“…Clinically healthy sport horses were found to be qPCR positive for common respiratory pathogens, with a weekly frequency ranging between 5.0 and 17.9% and an overall frequency of 9.9%, suggesting silently shedding horses are present in sport horse populations. EHV-4, EIV, and ERBV had frequencies of qPCR-positive swabs within the previously reported ranges of 0–3.2%, 0–1%, and 0–7.1%, respectively, for different populations of healthy horses [ 3 , 5 , 6 , 7 , 8 , 9 , 10 ]. EHV-1 and S. equi had frequencies at or above the highest previously reported frequencies of 3.8% and 0.6%, respectively [ 2 , 12 ].…”

“…Less characterized respiratory pathogens had qPCR positive swabs at frequencies also within previously reported ranges of 3–77.4% for EHV-2; 3–84.4% for EHV-5; and 19.7–79% for S. zooepidemicus [ 3 , 5 , 6 , 7 , 8 , 9 , 10 ]. The high detection rates determined for EHV-2, EHV-5, and S. zooepidemicus reflect the ubiquitous occurrence of these respiratory pathogens in show horses.…”

“…Subclinical infections with respiratory pathogens have been indicated as a possible explanation for outbreaks of disease [ 3 ], and horses shedding virus without clinical disease (silent shedder) have been identified as possible sources of transmission and spread [ 4 ]. The rate of silent shedders for respiratory pathogens is highly dependent on population age and use, as well as the specific pathogen tested, with reported frequencies ranging from 0 to 4% [ 2 , 3 , 5 , 6 , 7 , 8 , 9 , 10 ]. The stress of transport and competition may increase susceptibility to respiratory pathogens or even allow for latent viral infections to become active again [ 7 , 11 ].…”

Outbreak of feline infectious peritonitis (FIP) in shelter-housed cats: molecular analysis of the feline coronavirus S1/S2 cleavage site consistent with a ‘circulating virulent–avirulent theory’ of FIP pathogenesis

“…RNA from feces was extracted using methods previously reported. 27 Quantitative PCR analysis was performed and cycle threshold (Ct) values of positive samples are summarized in Table 2 .…”

Sandwich-Based Immunosensor for Dual-Mode Detection of Pathogenic F17–Positive Escherichia coli Strains

“…In fact, we recently found that camels affected by diarrhea expressed a higher prevalence of fimbriae F17 than clinically healthy camels (46.5% vs. 14.5%) [ 9 ]. Several other studies also reported the association of this adhesin with diarrhea and/or sepsis observed in newborn alpacas [ 10 ], calves [ 11 , 12 , 13 , 14 ], lambs [ 5 , 15 ] and horses [ 16 ]. All this justifies the growing interest in this virulence factor as a therapeutic target and for the design of diagnostic tools such as ELISA and biosensing platforms.…”