Diarrhea In Foals Research Articles

Epidemiological investigation of equine rotavirus B outbreaks in horses in central Kentucky

Using metagenomic sequencing we identified equine rotavirus group B (ERVB) of ruminant origin in foal diarrhea outbreaks in the 2021 foaling season. To further investigate ERVB occurrence and determine its environmental stability, we collected mare and foal fecal samples from different farms in central Kentucky during the 2022 foaling season. The RT-qPCR-based analyses showed that ERVB genome was detected in 16.67% (42/252) of surveyed mare samples and 26.56% (34/128) of foal samples. Furthermore, 94.12% (16/17) of collected soil samples and 100% (13/13) of water samples obtained from the ERVB-positive farm premises also tested weakly positive. In addition, ERVB genome fragments were detected in 58.33% (7/12) of indoor samples collected from the equipment/barn/hospital wards during the outbreak period. Finally, the seroprevalence study showed 87% (113/130) of surveyed horse serum samples were positive for ERVB antibodies. Despite unsuccessful attempts in ERVB cultivation, phylogenetic analyses showed that fecal ERVB strains representing 2022 and 2023 foal diarrhea outbreaks, like 2021 strains, were more closely related to ruminant rotavirus B than other viruses. Further sequence analyses revealed that none of the three viral capsid proteins, the primary targets of virus-neutralizing antibodies, exhibited notable mutations among ERVB strains circulated over the past three years. Our data demonstrated that ERVB was widespread in horses on affected farms with extreme stability in the farm environment. These findings continue to support the need for future surveillance of ERVB in horses and the surrounding environment, and the development of effective countermeasures to protect horses against this new viral disease.

PSI-17 Anti-endotoxin immunoglobulin (Ig) Y time course of oral passive transfer and impacts on growth performance in foals

Abstract Foal diarrhea is the leading cause of morbidity in neonatal foals and is often caused by various environmental pathogens. The adaptive immune system of foals depends on postpartum Ig absorption from maternal colostrum. To date, there lacks an easy way to supplement the immune system before intestinal closure. Thus, an anti-endotoxin IgY supplement derived from hyperimmunized hens may provide pathogen-specific protection if successful in passive transfer. Therefore, the objective was to determine the effects of an oral anti-endotoxin IgY on growth, stress, and passive transfer in neonatal foals with the hypothesis that IgY would successfully cross the gut barrier, positively impact growth, and ameliorate stress. To test this, Quarter Horse foals (n = 11) were randomly assigned based on foaling date to one of two treatment groups for a 28-d trial. Upon signs of impending parturition, mares were moved to box stalls (3.7 × 7.3 m) and parturition was attended. At birth, foals were assigned to either the control (CON; n = 5) or treatment group (TRT; n = 6). Foals assigned to TRT were supplemented with 40 g egg-derived anti-endotoxin IgY oral supplement (Camas, Inc.) dissolved in 50 mL ddH20 at 20 min after nursing and again at 12 h postpartum. The CON foals received isovolumetric ddH2O. Beginning at h 24, and daily thereafter, TRT foals received 1 g egg-derived anti-endotoxin IgY diluted in 5 mL ddH2O. Blood samples were collected from foals prior to nursing at h 0 and following the first oral treatment at h 2, 6,12, 24 and d 3, 7, 14, 21, 28. Harvested serum was analyzed for IgG, IgA, IgY, and cortisol by commercial ELISA. Data were analyzed using PROC MIXED in SAS v9.4 with repeated measures of time. Vital signs were similar for all foals regardless of treatment (P > 0.24) and all growth parameters increased over time (P < 0.01). There tended to be a treatment × time interaction for wither height (P = 0.10) where TRT wither height was greater at d 28 (P = 0.07). There was a treatment × time interaction (P < 0.01) for serum IgY concentrations where CON foals had undetectable concentrations for the duration of the study and TRT foals peaked on d 7 with detectable l concentrations remaining on d 28. Cortisol, however, was not influenced by treatment (P > 0.29), and IgG and IgA concentrations were only influenced by time (P < 0.01). In conclusion, despite having no effect on vital signs and stress, IgY is passively absorbed following oral administration to neonatal foals without negatively impacting the passive transfer of maternal IgG or IgA, lending to future work on pathogen-specific protection against foal diarrhea.

Effects of fecal microbiota transplantation on clinical outcomes and fecal microbiota of foals with diarrhea.

Diarrhea in foals can be associated with disruption of the intestinal microbiota (dysbiosis). Effective management of intestinal dysbiosis in foals has not been demonstrated. Fecal microbiota transplantation (FMT) in foals with diarrhea influences the intestinal microbiota and improves clinical and clinicopathological outcomes. Twenty-five foals <6 months of age with diarrhea and systemic inflammatory response syndrome at 3 veterinary hospitals. A prospective randomized placebo-controlled cohort study. Foals in the FMT group (n = 19) or control group (n = 9) received FMT or electrolyte solution once daily for 3 days. Fecal samples were obtained on Day 0 (D0), D1, D2, D3, and D7. Within group and between group data analyses were performed for clinical, clinicopathological, and microbiota variables. Treatment had no effect on survival (FMT 79%; control 100%, P = .3) or resolution of diarrhea (FMT 68%; control 55%, P = .4). On D3, the white blood cell count of the FMT group was lower than the control group (D3 FMT group median 6.4 g/L [5-8.3 g/L]; D3 control group median 14.3 g/L [6.7-18.9 g/L] P = .04). Heart rate reduced over time in the FMT group (D0 median 80 bpm [60-150 bpm]; D2 median 70 bpm [52-110 bpm] [P = .005]; and D3 median 64, [54-102 bpm] [P < .001]). Phylum Verrucomicrobiota, genus Akkermansia, and family Prevotellaceae were enriched in the FMT group on D1 (linear discriminate analysis > 4). In foals with diarrhea, FMT appears safe and can be associated with some clinical and microbiota changes suggestive of beneficial effect.

Genetic and antigenic characterization of two diarrhoeicdominant rotavirus A genotypes G3P[12] and G14P[12] circulating in the global equine population.

Equine rotavirus species A (ERVA) G3P[12] and G14P[12] are two dominant genotypes that cause foal diarrhoea with a significant economic impact on the global equine industry. ERVA can also serve as a source of novel (equine-like) rotavirus species A (RVA) reassortants with zoonotic potential as those identified previously in 2013-2019 when equine G3-like RVA was responsible for worldwide outbreaks of severe gastroenteritis and hospitalizations in children. One hurdle to ERVA research is that the standard cell culture system optimized for human rotavirus replication is not efficient for isolating ERVA. Here, using an engineered cell line defective in antiviral innate immunity, we showed that both equine G3P[12] and G14P[12] strains can be rapidly isolated from diarrhoeic foals. The genome sequence analysis revealed that both G3P[12] and G14P[12] strains share the identical genotypic constellation except for VP7 and VP6 segments in which G3P[12] possessed VP7 of genotype G3 and VP6 of genotype I6 and G14P[12] had the combination of VP7 of genotype G14 and VP6 of genotype I2. Further characterization demonstrated that two ERVA genotypes have a limited cross-neutralization. The lack of an in vitro broad cross-protection between both genotypes supported the increased recent diarrhoea outbreaks due to equine G14P[12] in foals born to dams immunized with the inactivated monovalent equine G3P[12] vaccine. Finally, using the structural modelling approach, we provided the genetic basis of the antigenic divergence between ERVA G3P[12] and G14P[12] strains. The results of this study will provide a framework for further investigation of infection biology, pathogenesis and cross-protection of equine rotaviruses.

Supplementation of Foals with a Saccharomyces cerevisiae Fermentation Product Alters the Early Response to Vaccination.

Feed supplements supporting animal welfare and performance are becoming increasingly important. Immunomodulatory effects of such products have been observed in many species. The aim of this study was to analyze whether food supplementation with a Saccharomyces cerevisiae fermentation product (SCFP) affects the occurrence of foal diarrhea in early life, and whether the SCFP feeding has an impact on the immediate response to a parenteral vaccination at the age of 6-9 months. Eleven foals received the SCFP (OLI) and eleven foals were fed a placebo (PLA) for 29 days. Growth, diarrhea, and diarrhea severity were observed until day 30. After weaning, at the age of 6-9 months, foals were vaccinated parenterally against influenza and tetanus. The supplementation had no statistically significant effect on diarrhea duration and severity. On the day of vaccination, PLA and OLI foals did not differ significantly regarding numbers of circulating blood leukocyte subsets. However, the response to vaccination differed significantly between OLI and PLA foals. In OLI foals, the numbers of the major leukocyte fractions (granulocytes, lymphocytes, monocytes, CD4+ T cells, CD8+ T cells, CD21+ B cells, and MHC-II+/CD21- cells) increased significantly 24 h after vaccination but remained unchanged in PLA foals. The observed results suggest that early life supplementation with an SCFP may affect the early immune response to an initial vaccination.

Equine rotaviruses: A review of old and new

SummaryRotaviral infection is the most common cause of foal diarrhoea, leading to severe dehydration and electrolyte derangements, which, left untreated, can be rapidly fatal. Until 2021, equine rotaviruses of group A (ERVA) were considered to be the only rotaviruses affecting horses; however, equine rotavirus group B (ERVB) has recently been identified in association with neonatal foal diarrhoea outbreaks. ERVA has been observed globally in many countries with large equine industries. Equine rotaviruses (ERV) are extremely contagious. Foals as young as 12 hours of age can show clinical signs. These clinical signs include inappetence, dullness, colic and characteristic watery diarrhoea that can be orange‐yellow to reddish‐brown in colour. Nowadays diagnosis relies mainly on qPCR—a test limited by the fact that PCR is a directed test requiring a priori knowledge of a pathogen's genome. The mainstay of therapy for rotaviral diarrhoea is supportive care since treatment directly targeting the virus itself is not available. Prevention relies on proper biosecurity protocols and, in the case of ERVA, vaccination of mares. Currently, researchers at the University of Kentucky are working on developing a vaccine for ERVB.

Evaluation of glutaraldehyde coagulation test and colostrum BRIX refractometer compared with SNAP foal IgG test in neonatal foals.

Prompt diagnosis of passive transfer failure in the neonatal period is important for early treatment. To compare the diagnostic performance of serum glutaraldehyde coagulation test (GCT) and colostrum BRIX% for failure to transfer passive immunity (FTPI) diagnosis with the results of SNAP foal test and to evaluate the results of serum GCT and colostrum BRIX% measurements in foals with diarrhoea in the 0-1 month period. In vitro experiments. Excess serum and colostrum (n: 298) from samples collected from newborn foals and their dams for clinical purposes were used. Foals were classified as FTPI positive (IgG < 8 g/L) or negative (IgG ≥ 8 g/L) using the SNAP foal test. We compared the sensitivity and specificity of serum GCT and colostrum BRIX % for diagnosing FTPI in all foals and in the sub-group of foals which developed diarrhoea within the first month of life was noted. The relationships between the results of the serum GCT and colostrum BRIX% and diarrhoea in foals with and without FTPI were evaluated. Serum GCT and colostrum BRIX % were statistically significantly different (p < 0.05) between the foals without FTPI and with FTPI classified according to the SNAP test. Using a cut-off value for serum GCT of >10, sensitivity was 100% (95% CI 92.9%-100%) and specificity 100% (98.3%-100%) while with a cut-off value of ≤24, with colostrum BRIX% of ≤24 sensitivity was 92% (80.9%-97.8%), and specificity was 98% (95.3-99.3). In the sub-group of foals without FTPI using a colostrum BRIX% cut-off value of ≤26 the sensitivity for prediction of diarrhoea in the 0-1 month period was only 72.4% (52.8-87.3, p < 0.001) with specificity 54.3% (47.6-61.1) but the test performance was not robust (ROC AUC 0.61). The number of repeated measurements in the evaluation of serum GCT, and colostrum BRIX% was low. More clinical problems could be examined. The serum GCT, and colostrum BRIX%, both economical and practical to use in the field, gave results comparable with the SNAP foal IgG test. The ability to accurately predict diarrhoea in the first month of life with these tests was limited.

Quadruplex Real-Time TaqMan® RT-qPCR Assay for Differentiation of Equine Group A and B Rotaviruses and Identification of Group A G3 and G14 Genotypes.

Equine rotavirus A (ERVA) is the leading cause of diarrhea in foals, with G3P[12] and G14P[12] genotypes being the most prevalent. Recently, equine G3-like RVA was recognized as an emerging infection in children, and a group B equine rotavirus (ERVB) was identified as an emergent cause of foal diarrhea in the US. Thus, there is a need to adapt molecular diagnostic tools for improved detection and surveillance to identify emerging strains, understand their molecular epidemiology, and inform future vaccine development. We developed a quadruplex TaqMan® RT-qPCR assay for differentiation of ERVA and ERVB and simultaneous G-typing of ERVA strains, evaluated its analytical and clinical performance, and compared it to (1) a previously established ERVA triplex RT-qPCR assay and (2) standard RT-PCR assay and Sanger sequencing of PCR products. This quadruplex RT-qPCR assay demonstrated high sensitivity (>90%)/specificity (100%) for every target and high overall agreement (>96%). Comparison between the triplex and quadruplex assays revealed only a slightly higher sensitivity for the ERVA NSP3 target using the triplex format (p-value 0.008) while no significant differences were detected for other targets. This quadruplex RT-qPCR assay will significantly enhance rapid surveillance of both ERVA and ERVB circulating and emerging strains with potential for interspecies transmission.

Characterization and Genomic Analysis of a Novel Lytic Phage DCp1 against Clostridium perfringens Biofilms

Clostridium perfringens (C. perfringens) is one of the foremost pathogens responsible for diarrhea in foals. As antibiotic resistance increases, phages that specifically lyse bacteria are of great interest to us with regard to C. perfringens. In this study, a novel C. perfringens phage DCp1 was isolated from the sewage of a donkey farm. Phage DCp1 had a non-contractile short tail (40 nm in length) and a regular icosahedral head (46 nm in diameter). Whole-genome sequencing indicated that phage DCp1 had a linear double-stranded DNA genome with a total length of 18,555 bp and a G + C content of 28.2%. A total of 25 ORFs were identified in the genome, 6 of which had been assigned to functional genes, others were annotated to encode hypothetical proteins. The genome of phage DCp1 lacked any tRNA, virulence gene, drug resistance gene, or lysogenic gene. Phylogenetic analysis indicated that phage DCp1 belonged to the family Guelinviridae, Susfortunavirus. Biofilm assay showed that phage DCp1 was effective in inhibiting the formation of C. perfringens D22 biofilms. Phage DCp1 could completely degrade the biofilm after 5 h of interaction. The current study provides some basic information for further research on phage DCp1 and its application.

Prevalence, genetic characteristics, and antimicrobial resistance of Clostridioides difficile isolates from horses in Korea

ObjectivesClostridioides difficile is an etiological agent of enteric diseases in humans and animals. Animals are considered a potential reservoir due to the genetic and antimicrobial resistance similarities between human and animal C. difficile isolates. In this study, we evaluated the genetic characteristics and antimicrobial resistance profiles of C. difficile isolated from 942 fecal samples collected from horses in South Korea during 2019–2020. MethodsThe C. difficile isolates were tested for toxin genes including tcdA (A), tcdB (B), and cdtAB (CDT) and deletions of the tcdC gene by PCR. In addition, ribotyping, multilocus sequence typing, and antimicrobial susceptibility tests were performed. ResultsTwenty-three (2.4%) C. difficile isolates were associated with diarrhea in foals under 1 year old during the spring–summer period. Of these, 82.6% were toxigenic strains, determined to be A+B+CDT+ (52.1%) or A+B+CDT‒ (30.4%). All isolates were susceptible to metronidazole and vancomycin, and resistant to cefotaxime and gentamicin, and 76.2% were multidrug resistant (MDR). RT078/ST11/Clade 5 was the most common genotype (47.8%), which was also found in animals and humans worldwide. All RT078/ST11/Clade 5 strains were toxigenic and had deletions of the tcdC gene. About half of these strains were resistant to moxifloxacin, and 63.6% were MDR. ConclusionsC. difficile isolates in this study consisted mostly of toxigenic and MDR strains, and their genetic properties were highly similar to human C. difficile isolates. These results suggest high possibilities of zoonotic transmission and can provide knowledge for establishing strategies for the treatment and prevention of C. difficile infection.

Characterization and complete genome analysis of a bacteriophage vB_EcoM_DE7 infecting donkey-derived Escherichia coli

A lytic bacteriophage vB_EcoM_DE7 (hereafter designated DE7) that could infect donkey-derived Escherichia coli was isolated. The bacteriophage was examined by transmission electron microscopy, and the result showed that DE7 belonged to the family Myoviridae. The microbiological characterization revealed that DE7 was stable over a broad range of pHs (3 ∼10) at 40-50 °C. The latent period was 10 min, and the burst size was 43 PFUs/infected cell. The whole-genome sequencing showed that DE7 was a dsDNA virus and had a genome of 86,130 bp. The genome contained 124 predicted open reading frames (ORFs), 35 of which had known functions, including DNA replication and modification, transcriptional regulation, structural and packaging proteins, and host cell lysis. Twenty tRNA genes were identified, but no genes associated with bacterial pathogenicity, lysogeny and drug resistance were identified. BLASTN analysis revealed that phage DE7 had a high sequence identity (96%) with Salmonella phage vB_SPuM_SP116, but it could not lyse any Salmonella strain tested in this study. DE7 was classified as a Felix O1-like virus based on its general characterization and genomic information. Since phage DE7 exhibited high efficacy in lysing E. coli and lacked genes associated with bacterial virulence, antimicrobial resistance and lysogeny, it could be potentially used to control foal diarrhoea caused by E. coli.

Enterocytozoon bieneusi Genotypes and Infections in the Horses in Korea.

Enterocytozoon bieneusi is a microsporidian pathogen. Recently, the equestrian population is increasing in Korea. The horse-related zoonotic pathogens, including E. bieneusi, are concerns of public health. A total of 1,200 horse fecal samples were collected from riding centers and breeding farms in Jeju Island and inland areas. Of the fecal samples 15 (1.3%) were PCR positive for E. bieneusi. Interestingly, all positive samples came from Jeju Island. Diarrhea and infection in foals were related. Two genotypes (horse1, horse2) were identified as possible zoonotic groups requiring continuous monitoring.

Gut Microbiota Manipulation in Foals-Naturopathic Diarrhea Management, or Unsubstantiated Folly?

Diarrhea in foals is a problem of significant clinical and economic consequence, and there are good reasons to believe microbiota manipulation can play an important role in its management. However, given the dynamic development of the foal microbiota and its importance in health and disease, any prophylactic or therapeutic efforts to alter its composition should be evidence based. The few clinical trials of probiotic preparations conducted in foals to date show underwhelming evidence of efficacy and a demonstrated potential to aggravate rather than mitigate diarrhea. Furthermore, recent studies have affirmed that variable but universally inadequate quality control of probiotics enables inadvertent administration of toxin-producing or otherwise pathogenic bacterial strains, as well as strains bearing transferrable antimicrobial resistance genes. Consequently, it seems advisable to approach probiotic therapy in particular with caution for the time being. While prebiotics show initial promise, an even greater scarcity of clinical trials makes it impossible to weigh the pros and cons of their use. Advancing technology will surely continue to enable more detailed and accurate mapping of the equine adult and juvenile microbiota and potentially elucidate the complexities of causation in dysbiosis and disease. In the meantime, fecal microbiota transplantation may be an attractive therapeutic shortcut, allowing practitioners to reconstruct a healthy microbiota even without fully understanding its constitution.

Identification of a Ruminant Origin Group B Rotavirus Associated with Diarrhea Outbreaks in Foals.

Equine rotavirus group A (ERVA) is one of the most common causes of foal diarrhea. Starting in February 2021, there was an increase in the frequency of severe watery to hemorrhagic diarrhea cases in neonatal foals in Central Kentucky. Diagnostic investigation of fecal samples failed to detect evidence of diarrhea-causing pathogens including ERVA. Based on Illumina-based metagenomic sequencing, we identified a novel equine rotavirus group B (ERVB) in fecal specimens from the affected foals in the absence of any other known enteric pathogens. Interestingly, the protein sequence of all 11 segments had greater than 96% identity with group B rotaviruses previously found in ruminants. Furthermore, phylogenetic analysis demonstrated clustering of the ERVB with group B rotaviruses of caprine and bovine strains from the USA. Subsequent analysis of 33 foal diarrheic samples by RT-qPCR identified 23 rotavirus B-positive cases (69.69%). These observations suggest that the ERVB originated from ruminants and was associated with outbreaks of neonatal foal diarrhea in the 2021 foaling season in Kentucky. Emergence of the ruminant-like group B rotavirus in foals clearly warrants further investigation due to the significant impact of the disease in neonatal foals and its economic impact on the equine industry.

Diarrhoea in foals

Diarrhoea is one of the most common clinical complaints in foals and can be associated with significant morbidity and mortality. Clinical presentation can vary from mild, transient diarrhoea through to severe enterocolitis with significant systemic complications. There are numerous infectious and non-infectious aetiologies, the prevalence of which varies between age groups. Supportive care for foals with diarrhoea includes fluid therapy, antimicrobials, ulcer protection and analgesia. It is important that treatment is initiated promptly and re-evaluated frequently in response to clinical progression, particularly in neonates that are susceptible to rapid deterioration. Many causes of diarrhoea in foals are contagious and strict biosecurity protocols should be implemented to try and control the spread of disease.

Equine rotavirus infection

ABSTRACTThis review briefly describes the virus classification, clinical signs, epidemiology, diagnosis, disinfection, and vaccines related equine group A rotavirus (RVA) infection. Equine RVA is one of the most important pathogens causing diarrhoea in foals. The main transmission route is faecal–oral, and the clinical signs are diarrhoea, fever, lethargy, and anorexia (decreased suckling). Some human RVA rapid antigen detection kits based on the principles of the immunochromatographic assay are useful for the diagnosis of equine RVA infection. The kits are used in daily clinical practice because of their rapidity and ease of handling. Equine RVA is a non-enveloped virus and is more resistant to disinfectants than enveloped viruses such as equine influenza virus and equine herpesvirus. Although amphoteric soaps and quaternary ammonium compounds are commonly used in veterinary hygiene, they are generally ineffective against equine RVA. Alcohol products, aldehydes, and chlorine- and iodine-based compounds are effective against equine RVA. Inactivated vaccines have been used for equine RVA infection in some countries. Pregnant mares are intramuscularly inoculated with a vaccine, and thus their colostrum has abundant antibodies against RVA at the time of birth. According to G and P classification defined in accordance with the VP7 and VP4 genes, respectively, the predominant equine RVAs circulating in horse populations globally are G3P[12] and G14P[12] equine RVAs, but the vaccines contain only the G3P[12] equine RVA strain. Ideally, a G14P[12] equine RVA should be added as a vaccine strain to obtain a better vaccine effect.

PSIV-2 Changes in free glutamine and glutamate in mare milk during early lactation

Abstract Glutamine plays an important role in neonatal health. This amino acid serves as a nitrogen and amine carrier between tissues, as a major energy source and as a precursor for nucleic acids and proteins in rapidly proliferating intestinal cells. This study aimed to evaluate changes over time in free Gln and Glu concentrations in mare milk in early lactation and their relationship with foal gut health. Thirteen Thoroughbred mare and foal pairs were studied. Milk samples were collected at 12 h, 3, 5, 7, 10, 14, and 21 d after parturition and daily milk yield was estimated at 7 and 14 d postpartum. Milk samples were centrifuged (10 min, 3500 x g, 4 °C) to remove fat, then centrifuged twice (5 min, 10,000 x g, 22 °C) to remove protein. Free Glu and Gln were analyzed in triplicate using a membrane-based glutaminase and glutamate oxidase method (YSI 2700 Analyzer, YSI Life Sciences, OH). Daily fecal scores were recorded to monitor foal diarrhea and body weights were recorded weekly. Mixed model ANOVA with repeated measures (SAS 9.4) were used to evaluate changes over time in free Gln and Glu. Relationships between variables were assessed using regression analyses and Pearson’s correlation coefficient. Free Gln and Glu changed over time (P &amp;lt; 0.0001). Glutamine increased from 12 h to 5 d, (0.24±0.11 mmol/L and 1.09±.11 mmol/L, respectively; P &amp;lt; 0.05) then decreased to 0.90±0.11 mmol/L by 21 d postpartum. In contrast, free Gln was the lowest at 12 h (0.36±0.04 mmol/L) and continued increasing through 21 d postpartum (0.80±0.04 mmol/L; P &amp;lt; 0.05). Bouts of diarrhea were negatively related to milk Gln (P &amp;lt; 0.05) and foal ADG was positively related to milk Glu (P &amp;lt; 0.05). These results suggest that Gln may have a role in foal gut health while Glu may influence foal growth.

Applications, challenges, and strategies in the use of nanoparticles as feed additives in equine nutrition.

The rapid expansion of nanotechnology has been transforming the food industry by increasing market share and expenditure. Although nanotechnology offers promising benefits as feed additives, their usage in equines is primarily geared toward immunotherapy, hyper-immunization techniques, drug delivery systems, grooming activities, and therapeutic purposes. Nanoparticles could be engaged as alternatives for antibiotic feed additives to prevent foal diarrhea. Gold nanoparticles are proved to provide beneficial effects for racehorses by healing joint and tendon injuries. Because of the poor bioavailability of micro-sized mineral salts, the usage of nano-minerals is highly encourageable to improve the performance of racehorses. Nano-Vitamin E and enzyme CoQ10 for equines are no longer a simple research topic because of the increased commercial availability. Employing nanotechnology-based preservatives may offer a promising alternative to other conventional preservatives in preserving the quality of equine feed items, even during an extended storage period. While nanoparticles as feed additives may provide multitudinous benefits on equines, they could elicit allergic or toxic responses in case of improper synthesis aids or inappropriate dosages. The safety of nano-feed additives remains uninvestigated and necessitates the additional risk assessment, especially during their usage for a prolonged period. To adopt nano-feed additives in horses, there is an extreme paucity of information regarding the validity of various levels or forms of nanoparticles. Further, the currently available toxicological database on the topic of nano-feed additives is not at all related to equines and even inadequate for other livestock species. This review aims to provide new insights into possible future research pertaining to the usage of nano-feed additives in equines.

Molecular analyses of G3A/G3B and G14 equine group A rotaviruses detected between 2012 and 2018 in Japan.

Equine group A rotaviruses (RVAs) cause diarrhoea in foals. We investigated the G genotypes of 360 RVA-positive samples obtained from diarrhoeic foals between 2012 and 2018 in the Hidaka district of Hokkaido, Japan, through sequence analysis of VP7. All samples were classified into genotypes G3A, G3B and G14. G3B RVAs were detected until 2016, and G3A RVAs were detected from 2016 to 2018. G14 RVAs were detected from 2012 to 2018. Although G3B RVAs had been circulating in Japan for a long time, G3A RVAs suddenly emerged in 2016, and have replaced G3B RVAs since 2017. Molecular analyses of VP7 and VP4 showed that these Japanese G3A RVAs are closely related to North American G3A RVAs detected in 2017. Additionally, whole-genome analyses suggested that genetic reassortments occurred between G3A and G14 RVAs in NSP1, NSP2, NSP4 and NSP5.

Development and evaluation of a one-step multiplex real-time TaqMan\xae RT-qPCR assay for the detection and genotyping of equine G3 and G14 rotaviruses in fecal samples

BackgroundEquine rotavirus A (ERVA) is the leading cause of diarrhea in neonatal foals and has a negative impact on equine breeding enterprises worldwide. Among ERVA strains infecting foals, the genotypes G3P[12] and G14P[12] are the most prevalent, while infections by strains with other genomic arrangements are infrequent. The identification of circulating strains of ERVA is critical for diagnostic and surveillance purposes, as well as to understand their molecular epidemiology. Current genotyping methods available for ERVA and rotaviruses affecting other animal species rely on Sanger sequencing and are significantly time-consuming, costly and labor intensive. Here, we developed the first one-step multiplex TaqMan® real-time reverse transcription polymerase chain reaction (RT-qPCR) assay targeting the NSP3 and VP7 genes of ERVA G3 and G14 genotypes for the rapid detection and G-typing directly from fecal specimens.MethodsA one-step multiplex TaqMan® RT-qPCR assay targeting the NSP3 and VP7 genes of ERVA G3 and G14 genotypes was designed. The analytical sensitivity was assessed using serial dilutions of in vitro transcribed RNA containing the target sequences while the analytical specificity was determined using RNA and DNA derived from a panel of group A rotaviruses along with other equine viruses and bacteria. The clinical performance of this multiplex assay was evaluated using a panel of 177 fecal samples and compared to a VP7-specific standard RT-PCR assay and Sanger sequencing. Limits of detection (LOD), sensitivity, specificity, and agreement were determined.ResultsThe multiplex G3 and G14 VP7 assays demonstrated high specificity and efficiency, with perfect linearity. A 100-fold difference in their analytical sensitivity was observed when compared to the singleplex assays; however, this difference did not have an impact on the clinical performance. Clinical performance of the multiplex RT-qPCR assay demonstrated that this assay had a high sensitivity/specificity for every target (100% for NSP3, > 90% for G3 VP7 and > 99% for G14 VP7, respectively) and high overall agreement (> 98%) compared to conventional RT-PCR and sequencing.ConclusionsThis new multiplex RT-qPCR assay constitutes a useful, very reliable tool that could significantly aid in the rapid detection and G-typing of ERVA strains circulating in the field.