Serology in horse research involves the study and analysis of blood serum to detect the presence of antibodies or antigens associated with infectious diseases and other health conditions. It is a diagnostic tool used to identify immune responses to pathogens, vaccination status, and exposure to specific diseases. Serological tests in equine research can include enzyme-linked immunosorbent assays (ELISA), complement fixation tests, and virus neutralization tests. These tests help in understanding the epidemiology of diseases, monitoring herd health, and informing vaccination strategies. This page compiles peer-reviewed research studies and scholarly articles that explore the methodologies, applications, and implications of serological testing in equine medicine.
DOLL ER, WALLACE E, RICHARDS MG.Manninger and Csontos reported that mares inoculated with equine abortion virus developed a transient fever 2 to 4 days after pharyngeal or intravenous inoculation and that an uninoculated horse in contact with the experimentally inoculated mares contracted a febrile disease resembling equine influenza. Also, mares that had aborted virus-infected fetuses were resistant to inoculation with equine influenza virus. From these observations, they proposed that virus abortions were a manifestation of infection of pregnant mares by the equine influenza virus. In reports on equine virus abortions, Kre...
TOMCSIK J, SCHWARZWEISS H.1. From beef stroma pretreated at room temperature with acetone and alcohol, a fraction was isolated with boiling 100% alcohol which, in a dilution of 1:500,000, combines with the sheep blood agglutinin of human serum produced during serum sickness. Using the terminology of Schiff, this fraction corresponds to the heterogenetic serum sickness antigen; it could be separated to a large extent from the heterogenetic mononucleosis antigen which also occurs in beef stroma.
2. The so-called serum sickness antigen also occurs heterogenetically in guinea pig kidney and it could also be isolated from ...
Olitsky PK, Harford CG.Young (12 to 15 day old) mice are approximately as susceptible to the virus of equine encephalomyelitis, Eastern or Western strain, when it is given intraperitoneally as are adult mice when the virus is injected intracerebrally. With this susceptibility by the intraperitoneal route as a basis, the injection of immune serum-virus mixtures intraperitoneally was found to result in protection in dilutions which give rise to infection after intracerebral inoculation. The difference of protective power by the two indicated routes was shown not to depend on the amount of inoculum nor on the age of th...
Elmahallawy EK, Hassan MF, Cano-Terriza D, Albalawi NO, Fajardo T, Gouda AA, Atiba A, Hendawy A, Villena I, Barakat AM, Alzaylaee H, Almería S....Toxoplasmosis, caused by the intracellular protozoan (), continues to be a widespread parasitic zoonotic disease globally. The seroepidemiology of infection in Egyptian equids, particularly donkeys, remains insufficiently explored. The present study was designed to assess the seroprevalence of in equines from Northern Egypt. Unassigned: A total of 360 serum samples from two equine species (157 horses and 203 donkeys) were obtained during 2023. The Modified Agglutination Test (MAT, cut-off of 1:25) was used to screen for the anti- antibodies. The study also analyzed potential risk factors th...
Crisman EC, Furr M, Ramachandran A.To determine the seroprevalence of Francisella tularensis in horses in Oklahoma and to describe factors associated with seropositivity. Unassigned: In this observational study, 238 frozen equine serum samples were tested for F tularensis by microagglutination assay (MAT). Samples were collected from 36 of 77 Oklahoma counties from 2021 through 2023. Exclusion criteria included insufficient sample quantity, cross-reactivity to Brucella abortus, and county outside of Oklahoma. The Fisher exact test was used to compare the proportion of positive tests by year, river basin, and topographic region....
Duaso J, Perez-Ecija A, Navarro A, Martínez E, De Las Heras A, Mendoza FJ.Equine piroplasmosis (EP) is an endemic parasitic disease in southern European countries, such as Spain. Andalusia, the most southwestern region of Europe, is the community with the highest number of registered horses and farms in Spain and one of the main international exporters of Andalusian (Spanish Purebred) horses worldwide. Considering the current expansion of this disease and the possible effect of climate change on its prevalence, studying the EP prevalence in this region is compelling. Molecular (PCR) and serological methods (cELISA and IFAT) were used to study the true and apparent p...
Picanço EMB, Assis FFV, Peleja PL, Sousa ABB, Barrêto Júnior RA, Lima RF, Neves KAL, Minervino AHH.This study aimed to determine the prevalence of antibodies against equine brucellosis in three distinct equid groups (farm animal, urban carthorse, and sport horse) in Western Pará, Brazil, and to identify associated risk factors. A cross-sectional study, involving 75 farms across 14 municipalities, sampled 1069 equids composed of urban carthorses and sport horses. Serum samples were tested for antibodies against spp. using the buffered acidified plate antigen (BAPA) test for screening, followed by the serum agglutination in tubes with 2-mercaptoethanol (2-ME) for confirmation. Univariate an...
Gonzalez-Obando J, Jaimes-Dueñez J, Zuluaga-Cabrera A, Forero JE, Diaz A, Rojas-Arbeláez C, Ruiz-Saenz J.Equine influenza is a highly contagious disease caused by the equine influenza virus (EIV). The occurrence of EIV outbreaks in America is associated with low levels of vaccination coverage. In Colombia, no seroprevalence evaluation has been carried out to estimate the distribution of the virus within the country. Our aim was to perform a sero-epidemiological survey of equine influenza infections and to identify associated risk factors in horses from four departments of Colombia. Serological testing was carried out by using an ELISA for the detection of IgG antibodies against the influenza A vi...
Busquets N, Gardela J, José-Cunilleras E, Solé A, Salvador MJ, Obón E, Molina-López R, Aranda C, Montalvo T, Corbella I, Bou-Monclús MA....West Nile virus (WNV), mainly transmitted by mosquitoes, poses significant health risks to humans and horses, particularly in endemic regions. The first detection of WNV lineage 2 in Spain was in 2017 in Catalonia (northeastern Spain). In 2023, WNV was confirmed in a young yellow-legged gull and a probable human case was notified within the urban settings. We aimed to define the zone of WNV circulation in the Barcelona Metropolitan Area where these infections occurred and the effectiveness of the One Health approach for early WNV detection. The Catalan WNV surveillance and control programs in...
Ganbaatar O, Batbaatar V, Kimura T, Ganzorig S, Tseren-Ochir EO, Suzuki Y, Takai S.ELISA antibody titers against Rhodococcus equi strain ATCC 6939 were measured in serum samples collected from 644 horses aged 1-21 years at 13 provinces and the capital of Mongolia, of which 631 (98%) samples showed values of approximately zero. The mean antibody titers in the 14 areas ranged from -0.08 to -0.01. Nine samples (1.4%) exhibited titers of 0.1-0.2, and surprisingly, four horses (0.6%) each aged 2, 5, 8, and 9 years demonstrated positive values in the range of 0.3-0.8. Considering the age resistance characteristic of this disease, the positive horses were hypothesized to exhibit no...
Motta D, Aymée L, Roussouliéres I, Di Azevedo MIN, Jacob JCF, Lilenbaum W.Leptospirosis is a zoonotic disease caused by spirochetes of the genus Leptospira. Equine genital leptospirosis (EGL) has been described as a chronic and silent syndrome, presenting reproductive alterations such as abortion, stillbirth, placentitis, embryonic loss, repeat breeding syndrome, and subfertility. This study aimed to investigate the genital Leptospira infection in naturally infected mares with poor reproductive performance, as well as to genetically characterize the agents. A total of 41 mares with a history of poor reproductive performance were selected. Sera were collected for ser...
Cardoso TL, Wozeak DR, Pereira IL, da Silva Ribeiro LD, Rodrigues RO, Hartwig DD.Leptospirosis is a globally distributed zoonosis that affects both humans and animals, with being the main causative agent. In horses, the disease is associated with considerable economic losses. The Microscopic Agglutination Test (MAT) is the reference test for diagnosis but has limitations, emphasizing the need for effective diagnostic alternatives. In this study, was evaluated the use of a recombinant chimera, composed of ErpY-like and LemA proteins, as an antigen for ELISA-based detection of equine leptospirosis. The chimera was successfully expressed, purified and tested on 915 horse ser...
Acevedo-Jiménez GE, Morales-González C, Akbarin MM, Rodríguez-Murillo C, González-Fernández VD, Avila-De la Vega LM, García-Flores MM....Equine infectious anemia virus (EIAV) is a globally significant equine pathogen, and its control relies on effective serological surveillance. The agar gel immunodiffusion (AGID) test, the WOAH-prescribed method, has limitations in sensitivity. This study developed and validated an indirect ELISA using a synthetic peptide derived from a conserved region of the EIAV gp90 surface glycoprotein. The assay was evaluated using 773 horse sera from the Metropolitan Zone of the Valley of Mexico and compared to the AGID test. The gp90-EIAV ELISA demonstrated a sensitivity of 85.3 % and a specificity o...
Badr C, Arbi M, Souiai O, Larbi I, Nsiri J, Elbehi I, Bouslama Z, Bennour MA, Essaied MS, Ines Khosrof , Chabchoub A, Ben Aoun B, Ghram A, Lachheb J.Equine influenza (EI) is a highly contagious viral respiratory disease affecting equids, with the potential of causing widespread outbreaks across Europe, the Americas, Asia, and other regions of the world. In Tunisia, in the spring of 2021, an EI virus outbreak occurred in a farm housing purebred Arabian horses that exhibited respiratory signs. This outbreak led to a national lockdown on horse movements and the cancellation of equestrian events. A total of 432 serum samples, collected from 2018 to 2021, were tested using ELISA competition assay. In addition, 100 Nasal swabs were collected dur...
Valderrama-Martinez C, Packham A, Smith W, Mendoza-Flores JE, Zheng S, Chigerwe M, Plancarte M, Aleman M.Long-term freezing storage can alter the stability of proteins, thereby compromising accurate determination of indirect fluorescent antibody test (IFAT) titers that support the diagnosis of equine protozoal myeloencephalitis. Objective: Assess the effect of long-term storage at -80°C on IFAT against S. neurona and N. hughesi in equine serum and cerebrospinal fluid (CSF). Methods: Paired serum and CSF (n = 46), and serum only (n = 25) samples. Methods: Prospective study of samples stored 6-12, 13-18, and 19-24 months. Comparing antibody titers across time points, McNemar and Wilcoxon...
Chinyere CN, Ajaebili AC, Peter-Ajuzie IK, Galadima HB, Daodu OB, Fatola OI, Okolo CC, Alaba BA, Akinniyi OO, Omoniwa DO, Edeh ER, Olorunfemi AB....African horse sickness (AHS) is a severe, infectious arthropod-borne disease of equids caused by the AHS virus (AHSV). It is endemic in Sub-Saharan Africa, and several sporadic outbreaks of the disease have been reported in Nigeria in the past 5 decades. Following a recent outbreak of the disease in Lagos State, this study was conducted to investigate the prevalence of (AHSV) antibodies in apparently healthy horses and some selected wildlife sampled in four geographical regions of Nigeria. Using a competitive enzyme-linked immunosorbent assay, 575 serum samples collected from horses in five ...
Nemoto M, Kawanishi N, Kamei R, Furusho K, Kawauchi K, Yabuuchi Y, Oue Y, Uchida Y, Nishiura H, Reedy SE, Chambers TM, Li F, Bannai H, Yamanaka T....In April and May 2025, outbreaks of equine influenza occurred for the first time in 17 years in Japan. Equine influenza virus (EIV) of the H3N8 subtype was mainly detected in heavy draft horse populations in Kumamoto Prefecture and the Tokachi area of Hokkaido. In total, 10 EIVs were isolated from infected horses and then were used for genetic and serological analyses. Phylogenetic analysis of all eight genes revealed that all Japanese isolates were clustered with the Florida sublineage clade 1 (Fc1) viruses and were closely related to North American Fc1 viruses detected in 2024-2025. The resu...
Şahinkesen İ, Bilge-Dağalp S.Equine herpesvirus 1 (EHV-1) and Equine herpesvirus 4 (EHV-4) are major viral pathogens of horses that contribute to respiratory disease, abortion, and neurological disorders, leading to economic losses in the equine industry. Accurate serological diagnosis is critical for disease surveillance and control. This study aimed to develop and validate an in-house enzyme-linked immunosorbent assay (ELISA) for detecting antibodies against EHV-1 and EHV-4 in horse sera. Serum samples previously confirmed by virus neutralization test (VNT) and a commercial ELISA were used to optimize the assay. Cut-off...
Carey KJ, Smith I, Hartley CA, Bailey KE, McIntosh K, Broder CC, Gilkerson JR.Hendra virus (HeV) is a high consequence pathogen that causes severe respiratory and/or neurological disease in both horses and humans with high mortality. The equine vaccine, Equivac® HeV, is a recombinant soluble version of the G glycoprotein of HeV (HeV-sG) that elicits a potent HeV-neutralising antibody response in adult horses and also provides indirect protection for humans. Maternally derived HeV-G specific antibodies could interfere with subsequent foal vaccination, although other factors such as foal age and the suitability of vaccination protocols that have been optimised for adult ...
McLinden LA, Kemp-Symonds JG, Daly JM, Blanchard AM, Waller AS, Freeman SL.Infection with Streptococcus equi subspecies equi (S. equi) is characterised by acute disease, with about 10% of infected animals remaining persistently infected. Clinically, infection with S. equi cannot readily be distinguished from infection caused by other respiratory pathogens, including Streptococcus equi subspecies zooepidemicus (S. zooepidemicus), equine influenza virus, and equine herpes virus. Screening protocols, with appropriate quarantining facilities, are important to detect horses infected with S. equi and avoid strangles outbreaks. Virulent strains of S. zooepidemicus can also ...
