Equine Infectious Anemia (EIA) is a viral disease affecting horses, caused by the Equine Infectious Anemia Virus (EIAV), a member of the Lentivirus genus. The disease is characterized by intermittent fever, anemia, edema, and weight loss, though some horses may remain asymptomatic carriers. Transmission occurs primarily through blood-feeding insects such as horseflies and deerflies, or through contaminated instruments. EIA is diagnosed using serological tests, with the Coggins test being a commonly used method for detection. There is no vaccine or cure for EIA, and management primarily focuses on prevention and control measures to limit transmission. This page assembles peer-reviewed studies and scholarly articles that explore the pathogenesis, epidemiology, diagnostic methods, and management strategies related to Equine Infectious Anemia.
de Boer GF, Osterhaus AD, van Oirschot JT, Wemmenhove R.The prevalence of antibodies to various viruses was investigated in a series of serum samples collected from horses in the Netherlands between 1963 and 1966 and from 1972 onwards. Neutralizing antibodies to equine rhinopneumonitis virus, equine arteritis virus and to equine rhinovirus types 1 and 2 were detected in respectively 76%, 14%, 66% and 59% of the equine serum samples tested. The observed incidence of serum samples positive to equine adenovirus in the complement fixation test was 39%. Precipitating antibodies to equine infectious anaemia virus were detected only in serum samples from ...
de Boer GF, Osterhaus AD, van Oirschot JT, Wemmenhove R.The prevalence of antibodies to various viruses was investigated in a series of serum samples collected from horses in the Netherlands between 1963 and 1966 and from 1972 onwards. Neutralizing antibodies to equine rhinopneumonitis virus, equine arteritis virus and to equine rhinovirus types 1 and 2 were detected in respectively 76%, 14%, 66% and 59% of the equine serum samples tested. The observed incidence of serum samples positive to equine adenovirus in the complement fixation test was 39%. Precipitating antibodies to equine infectious anaemia virus were detected only in serum samples from ...
Rice NR, Coggins L.In the endogenous reverse transcriptase reaction, equine infectious anemia virus is able to synthesize complementary DNA (cDNA) of 8,000 nucleotides in high yield. After 2 h in 50 muM dNTP, about 2.8 mug of cDNA per mg of protein is produced, almost 30% of which is long cDNA. The system thus compares favorably with the other two well-characterized endogenous reaction systems, Moloney murine leukemia virus and avian sarcoma virus. Elongation rates of 100 to 150 nucleotides per min have been observed; these rates are comparable to those seen with purified avian myeloblastosis virus reverse trans...
Charman H, Long C, Coggins L.Three structural proteins of equine infectious anemia virus were purified, labeled with 125I, and utilized in radioimmunoassays with horse sera and antisera to heterologous retroviruses. Whereas radioimmunoassay titers for the major protein, p25, were 500- to 1,000-fold higher than titers in immunodiffusion, for clinical purposes these two procedures were equivalent. Antibodies to two low-molecular-weight proteins, p12 and p10, were also found in infected horses, but with a lower frequency and lower titers. As a rule, only sera positive for p25 also contained antibody to p12 and p10. Antisera ...
Issel CJ, Adams WV.In 1975, a survey was conducted in East Baton Rouge Parish, Louisiana, to determine the prevalence of equine infectious anemia. Using the agar gel immunodiffusion test, 94 of 1,398 horses (6.7%) were found to be infected. Infection rates were especially high in areas where clinical cases of equine infectious anemia had been diagnosed. Clinical signs compatible with the disease were noted in 1 of the 94 seropositive horses. The sample set of 1,398 horses represented 22% of the census population obtained during the 1971 Venezuelan equine encephalomyelitis vaccination campaign.
Klevjer-Anderson P, Cheevers WP, Crawford TB.Equine dermal fibroblasts persistently infected with equine infectious anemia virus (EIAV) show no alterations in cell morphology or growth kinetics when compared to uninfected cells. The percentage of cells immunofluorescent positive for viral proteins fluctuated, depending upon the stage of the cell cycle, while production of extracellular virus was uniform throughout the cell cycle, increasing only as the cell number increased. This was shown in log versus stationary phase cultures as well as in cultures synchronized by sterum starvation. The establishment of productive infection did not re...
Rice NR, Simek S, Ryder OA, Coggins L.Equine infectious anemia virus (EIAV) recently has been shown to possess a high-molecular-weight RNA genome and a virion reverse transcriptase. We completed the demonstration that EIAV is a retrovirus by showing the presence of proviral DNA in equine cells infected in vitro, but not in normal horse DNA. These studies were performed by using a highly representative cDNA probe synthesized by the virion polymerase. It was found that this cDNA reassociated extensively, and with high thermal stability, with either viral RNA or DNA extracted from infected cells, but showed no detectable reassociatio...
Shen DT, Gorham JR, Jones RH, Crawford TB.Laboratory-colonized mosquitoes, Culex tarsalis, aedes aegypti, Culiseta inornata, and Anopheles free-borni, and the biting gnat, Culicoides variipennis, were exposed to equine infectious anemia virus. Exposure to the virus was by intrathoracic inoculation for mosquitoes and by oral ingestion of an infective blood meal through a membrane for C variipennis. After various intervals, groups of 15 to 20 insects were homogenized and inoculated into susceptible ponies. Positive immunodiffusion test results were used as criterion for equine infectious anemia infection in ponies. Virus was not detecte...
Gonda MA, Charman HP, Walker JL, Coggins L.Scanning and transmission electron microscopy were used to study in detail the morphogenesis and replication of equine infectious anemia virus (EIAV) in cultured, persistently infected equine fetal kidney fibroblasts. The EIAV was shown by thin-section electron microscopy to resemble morphologically more closely the members of the genus Lenti-virus in the family Retroviridae than other genera. Scanning electron microscopy demonstrated budding virus on only about 5% of the equine fetal kidney fibroblasts; however, the entire surface of these cells was involved in viral replication. Except where...
McIlwraith CW, Kitchen DN.Neurologic signs and neuropathologic lesions associated with a case of equine infectious anemia in a 7 year old Quarter-horse mare were studied. Clinical signs included depression, disorientation, circling, knuckling at the fetlock and hypermetria. The neuropathologic lesions were characterized by a granulomatous ependymitis, subependymal encephalitis, choroiditis and hydrocephalus. These lesions were associated with signs of neurologic dysfunction which were the cause of the prominent clinical features.
McGuire TC, Crawford TB.Equine fibroblasts persistently infected with equine infectious anemia virus acquire a new cell membrane antigen demonstrable by indirect radioimmunoassay, using infected horse serum as an antibody source.
Kemen MJ, McClain DS, Matthysse JG.Equine infectious anemia virus was transmitted from an acutely ill and an inapparently infected pony to uninfected ponies by the interrupted feeding of horse flies (tabanids). Transmission from acutely ill ponies was not accomplished following: (1) the interrupted feeding of a single horse fly, (2) bites of horse flies that had fed on an acutely affected pony 24 hours earlier, (3) bites of horse flies that had oviposited after feeding on an acutely affected pony, or (4) the inoculation of larval material derived from horse flies that had fed to repletion. It was concluded that horse fly transm...
Etcheverrigaray ME, Oliva GA, Zabala Suárez JE.Twenty seven per cent of 238 serum samples obtained from horses with clinical diagnosis were positive for the immunodifusion test, while 17% of the 452 sera obtained from asintomatic horses were positive. Twenty one per cent of the 870 sera studied were positive.
Tekerlekov P, Dilovski M, Enchev S, Peneva I.Coggins' immune diffusion test was modified, and was applied as a screening one in the study of the epizootic status. The positive reactions were characterized by the production of a precipitation line between the antigen and the respective serum that was tested. The appearance of such a line was associated with that formed with the use of the positive control serum, pointing to a reaction of identity. With the weakly positive reactions the ends of the precipitin lines, formed with the use of the positive control serum, were found to deviate slightly toward the site where the antigen had been ...
McConnel MB, Katada M, McConnell S, Moore R.Electron microscopy was used to demonstrate the presence of viral particles in primary cultures of leukocytes taken from a horse after SC inoculation with the Wyoming strain of equine infectious anemia virus. Unlike previous studies, the exposure virus was not passaged through cell culture prior to horse inoculation. Cultures were begun approximately 1 week before and 1 week after the 1st pyrexic period after inoculation. In both samples, viral particles and cytoplasmic alterations were observed resembling those previously reported in equine infectious anemia virus and other retravirus-infecte...
Hallauer C.1. Equine infectious anemia (EIA) is an immunologically-medicated disease. Immune complexes formed in blood and tissues are responsible for most symptoms and lesions (anemia, splenomegaly, lymphadenopathy, glomerulonephritis, etc.). In addition, a state of cellular hypersensitivity of the delayed type is involved in the pathogenesis. 2. Periodical attacks of pyrexia and clinical illness in the presence of immunity are caused by antigenically-modified variants of virus. By means of immunosuppressive treatments similar relapses of fever associated with the appearance of new virus variants can be...
Shen DT, Crawford TB, Gorham JR, McGuire TC.Twelve chemicals and commercial disinfectants were tested for inactivation of equine infectious anemia virus. In the presence of 10% bovine serum, all chemicals inactivated 4 log10 (based on 0.1 ml) of the virus within 5 minutes at 23 C. A reduction of at least 4 log10 was observed when the virus was exposed for 1 minute to substituted phenolic disinfectants (3 commercial preparations and sodium orthophenylphenate), halogen derivatives (iodophor and sodium hypochlorite), chlorhexidine, and 70% ethanol. Sodium hydroxide (5%), 2% formalin, and 2% glutaraldehyde were slower to inactivate the viru...
Coggins L, Auchnie JA.Equine infectious anemia (EIA) has been enzootic in Hong Kong since the end of World War II. In 1972, a serologic survey of the horses at the Hong Kong Jockey Club indicated 23% prevalence of EIA. Disease control measures were instituted, and the spread of infection was reduced. In 1976, the prevalence of EIA was believed to be sufficiently low to implement procedures for eradication of EIA from all horses in Hong Kong. A correlation between EIA and poor performance of racehorses was demonstrated.
Lin YZ, Deng XL, Shen N, Lü XL, Zhao LP, Kong XG, Shao YM, Zhou JH.To develop a flow cytometry using (5-carboxyfluorescein diacetate succinmidyl ester, CFSE) to detect the proliferation of specific T lymphocytes from equine infectious anemia virus (EIAV). Methods: Peripheral blood mononuclear cells (PBMC) were isolated, stained with CFSE and incubated with EIAV for 5 days. After interacted with either CD4(+) or CD8(+) antibody, the cells were detected for proliferated population, which contained serially 2-fold reduced CFSE in CD4(+) and CD8(+) T lymphocytes. Results: The concentration of CFSE, and the type, concentration and reaction time of EIAV-specific an...
Asseged BD, Habtemariam T, Tameru B, Nganwa D.Deriving horse oocytes in the USA is hampered by the lack of abattoirs processing horse carcasses which could provide abundant quantities of ovaries from slaughtered mares. Therefore, several cloning industries in the USA are attempting to import cloned horse embryos from Canada. Like any agricultural commodity, cloned embryos pose a risk of introduction of exotic animal diseases into the importing country. Under such circumstances, risk assessment could provide an objective, transparent, and internationally accepted means for evaluating the risk. This quantitative risk assessment (QRA) was in...
Han X, Zhang P, Yu W, Xiang W, Li X.The Chinese EIAV vaccine is an attenuated live virus vaccine obtained by serial passage of a virulent horse isolate (EIAV) in donkeys (EIAV) and, subsequently, in donkey cells in vitro. In this study, we compare the env gene of the original horse virulent virus (EIAV) with attenuated strains serially passaged in donkey MDM (EIAV) and donkey dermal cells (EIAV). Genetic comparisons among parental and attenuated strains found that vaccine strains contained amino acid substitutions/deletions in gp90 that resulted in a loss of three potential N-linked glycosylation sites, designated g5, g9, and g1...
Han X, Zou J, Wang X, Guo W, Huo G, Shen R, Xiang W.The Chinese EIAV vaccine is an attenuated live-virus vaccine obtained by serial passage of a virulent horse isolate (EIAV(L)) in donkeys (EIAV(D)), and subsequently in donkey cells in vitro. In this study, we compare the env gene of the original horse virulent virus (EIAV(L)) with attenuated strains serially passaged in donkey MDM (EIAV(DLV)), and donkey dermal cells (EIAV(FDDV)). Genetic comparisons among parental and attenuated strains found that vaccine strains contained amino acid substitutions/deletions in gp90 that resulted in a loss of three potential N-linked glycosylation sites, desig...
McGuire TC.Isolated equine immunoglobulin (Ig)G(T) antibodies to equine infectious anemia virus P26 antigen did not precipitate with antigen when the ratio of antibody to antigen was high. However, at lower ratios of antibody to antigen precipitation occurred. In addition, complement-fixation by IgG and P26 antigen was inhibited by high concentrations of IgG(T). The unusual reaction pattern noted with IgG(T) antibodies was still detectable by the immunodiffusion test for equine infectious anemia virus. In situations of nonprecipitability by IgG(T), the adjacent positive control line was inhibited, and th...
Kong XG, Pang H, Sugiura T, Sentsui H, Onodera T, Matsumoto Y, Akashi H.Equine infectious anemia virus (EIAV) core proteins were obtained from a baculovirus expression system. Recombinant baculoviruses (rBVs) highly expressed the Gag precursor and p26 antigens in an rBV-infected Sf21 cell culture supernatant. Enzyme-linked immunosorbent assay (ELISA) and agar gel immunodiffusion (AGID) were conducted using the expressed proteins to detect antibodies from experimentally infected horses. The expressed antigens showed low background levels, high specificity and sensitivity in ELISA and AGID. The results of the serological tests using the expressed antigens were ident...
Palomba E, Martone F, Meduri A, Vaccaro A, Damiani N.A description is given of an outbreak of equine infectious anaemia (E.I.A.) in Campania [at Naples and Aversa (Caserta)]; it was diagnosed by clinical, pathological and serological examinations (Coggins test). Using the serum of 45 horses with E.I.A. and 11 healthy horses (controls), numerous investigations were carried out on: enzymes, intrinsic coagulation factors, lipids and other substances. The results obtained were very interesting and show that in this disease there are significant increases in many enzymes (LDH, LAP, gamma-GT, CPK, PK and ALD) and copper. Insignificant increases were f...
Murakami K, Sentsui H, Shibahara T, Yokoyama T.Three horses were experimentally infected with equine infectious anemia virus (EIAV). All horses were febrile after inoculation with EIAV and then developed chronic symptoms with intermittent fever. The febrile period was characterized by a rise in body temperature with reduced PBL and erythrocyte counts. Flow cytometric analysis showed that the reduced number of lymphocytes was due to significant decreases in CD4+ and CD8+ T cells in the absence of any change in B cell number. At the end of the febrile period the body temperature began to recover and numbers of CD4+ and CD8+ T cells showed a ...
Liu C, Cook SJ, Craigo JK, Cook FR, Issel CJ, Montelaro RC, Horohov DW.Unlike other lentiviruses, EIAV replication can be controlled in most infected horses leading to an inapparent carrier state free of overt clinical signs which lasts for many years. While the resolution of the initial infection is correlated with the appearance of virus specific cellular immune responses, the precise immune mechanisms responsible for control of the infection are not yet identified. Since the virus undergoes rapid mutation following infection, the immune response must also adapt to meet this challenge. We hypothesize that this adaptation involves peptide-specific recognition sh...
Liu Q, Wang XF, Du C, Lin YZ, Ma J, Wang YH, Zhou JH, Wang X.Integration is an important feature of retroviruses and retrovirus-based therapeutic transfection vectors. The non-primate lentivirus equine infectious anaemia virus (EIAV) primarily targets macrophages/monocytes . Investigation of the integration features of EIAV strains, which are adapted to donkey monocyte-derived macrophages (MDMs), is of great interest. In this study, we analysed the integration features of EIAV in equine MDMs during infection. Our previously published integration sites (IS) for EIAV in fetal equine dermal (FED) cells were also analysed in parallel as references. Sequenc...
Swardson CJ, Lichtenstein DL, Wang S, Montelaro RC, Kociba GJ.To characterize infection of bone marrow-derived macrophages (BMDM) with equine infectious anemia virus (EIAV) by determining virus production, effects on viability, and induction of cytokines. Methods: BMDM obtained from bone marrow of 6 clinically normal adult horses. Methods: BMDM were infected with EIAV at a multiplicity of infection of 8. Cell viability, percentage of cells with detectable viral protein, reverse transcriptase activity, and concentrations of infective virus (focus-forming units/ml), interleukin 6, and tumor necrosis factor-alpha were measured in culture supernatant samples...
Wöhrl BM, Howard KJ, Jacques PS, Le Grice SF.A comparative study of recombinant 51- and 66-kDa subunits comprising equine infectious anemia virus reverse transcriptase (EIAV RT) is reported. Both polypeptides sedimented as stable homodimers (molecular mass, 102 and 132 kDa, respectively) when analyzed by rate sedimentation through glycerol gradients. Consistent with their dimer composition, each preparation displayed considerable levels of both RNA- and DNA-dependent DNA polymerase activity on different homopolymeric template/primer combinations. However, a detailed analysis of the polymerization products indicated qualitative difference...
Soutullo A, García MI, Bailat A, Racca A, Tonarelli G, Malan Borel I.Equine infectious anemia virus (EIAV) is a lentivirus causing a persistent infection in horses characterized by recurrent febrile episodes and high levels of viremia associated with a novel antigenic strain of the virus. The virus contains two envelope glycoproteins, gp90 and gp45, and four internal proteins, p26, p15, p11 and p9. Considering that the most infected horses are able to restrict EIAV replication to very low levels and that gp45 and p26 contain highly conserved epitopes among lentiviruses, it would be necessary to identify those conserved epitopes stimulating cellular and humoral ...
Dominguez M, Münstermann S, Murray G, Timoney P.The 'high-health, high-performance' (HHP) horse concept has been developed by the World Organisation for Animal Health (OIE) together with the F6ddration Equestre Internationale and the International Federation of Horseracing Authorities. This concept is outlined in the OIE Terrestrial Animal Health Code (Chapter 4.16). It aims to address impediments to the international movement of competition horses through a harmonised, practically feasible, globally applicable framework based on simplified certification requirements for the temporary importation of HHP horses and for their return to their ...
Cao XZ, Lin YZ, Li L, Jiang CG, Zhao LP, Lv XL, Zhou JH.The threshold hypothesis of attenuated lentiviral vaccine considers that the type of host response to infections of lentiviruses depends on the viral load. To evaluate the correlation between viral loads of the attenuated vaccine strain of equine infectious anemia virus (EIAV) and their effects to induce protective immunity, longitudinal plasma viral loads in groups of horses inoculated with either an attenuated EIAV vaccine strain (EIAV(DLV125)) or sub-lethal dose of an EIAV virulent strain (EIAV(LN40)) were compared. Similar levels of plasma viral loads ranging from 10(3)-10(5) copies/mL wer...
Pang H, Kong XG, Sentsui H, Kono Y, Sugiura T, Hasegawa A, Akashi H.Six strains of equine infectious anemia virus (EIAV) were recovered from febrile and non-febrile stages of a horse experimentally infected with the P337-V70 strain given once to a horse. The env gp90 genes of the isolates, the P337-V70 and P337-V26, avirulent virus derived from the P337-V70 strain, were sequenced. A comparison of the gp90 gene sequences revealed that amino acid variations among the viruses tested showed as high as 8.2 to 11.5%. In addition, the comparison also indicated that the isolates that recovered from the non-febrile stage were contained in nucleotide insertions in the p...
de Arruda Coutinho LC, de Jesus AL, de Paiva Fontes KF, Coimbra EC, Mariz FC, de Freitas AC, de Cássia Carvalho Maia R, de Castro RS.Equine Infectious Anemia (EIA) is a persistent lentivirus infection of horses which causes a chronic clinical condition with worldwide importance in veterinary medicine. The p26 protein is usually prepared for use as an antigen in serological tests for EIA diagnosis since it is a well-conserved gene sequence and very immunogenic. In view of the ability of yeast to make post-translational modifications of proteins, this study was carried out to allow Pichia pastoris to be used for the expression of a synthetic codon-optimized EIAV p26 gene. The gene was cloned into pPICZαA vector after appropr...
Wang J, Wen S, Zhao R, Qi J, Liu Z, Li W, An J, Wood C, Wang Y.The conjugation of small ubiquitin-like modifier (SUMO) to the target protein, namely, SUMOylation, is involved in the regulation of many important biological events including host-pathogen interaction. Some viruses have evolved to exploit the host SUMOylation machinery to modify their own protein. Retroviral Gag protein plays critical roles in the viral life cycle. The HIV-1 p6 and the Moloney murine leukemia virus CA have been reported to be conjugated with SUMO. In this study, we report for the first time, to our knowledge, the covalent conjugation of equine infectious anemia virus (EIAV) G...
Kaiser A, Meier HP, Doherr MG, Perler L, Zanoni R, Gerber V.Since 1991, no cases of Equine Infectious Anemia (EIA) have been reported in Switzerland. Risk factors for introduction of the virus into Switzerland are still present or have even increased as frequent inapparent infections, large numbers of imported horses, (since 2003) absence of compulsory testing prior to importation, EIA cases in surrounding Europe, possible illegal importation of horses, frequent short-term stays, poor knowledge of the disease among horse owners and even veterinarians. The aim of this study was to provide evidence of freedom from EIA in imported and domestic horses in S...
Boldbaatar B, Bazartseren T, Koba R, Murakami H, Oguma K, Murakami K, Sentsui H.In the current study, primers described previously and modified versions of these primers were evaluated for amplification of full-length gag genes from different equine infectious anemia virus (EIAV) strains from several countries, including the USA, Germany and Japan. Each strain was inoculated into a primary horse leukocyte culture, and the full-length gag gene was amplified by reverse transcription polymerase chain reaction. Each amplified gag gene was cloned into a plasmid vector for sequencing, and the detectable copy numbers of target DNA were determined. Use of a mixture of two forward...
Carpenter TE, McBride MD, Hird DW.We examined the risk of importing and mistakenly releasing equine infectious anemia virus (EIAV)-infected horses into California. A computer simulation model was constructed to evaluate current and alternative quarantine station procedures; 150,000 iterations were performed to simulate 15 different scenarios of 10,000 horses imported into the state over a 14-year period. Simulation results showed that under current conditions of low EIAV prevalence in exporting countries, increasing the quarantine period would not decrease the number of EIAV-infected horses mistakenly released from quarantine....
Sentsui H, Wu D, Murakami K, Kondo T, Matsumura T.Recombinant equine interferon-gamma (reIFN-gamma) was prepared using a baculovirus expression system and its antiviral activity was investigated using several equine viruses. The reIFN-gamma suppressed the replication of all equine viruses used in the present experiment in horse cell cultures, but did not affect the growth of host cells at concentrations of less than 1000 u/ml. A strong antiviral effect was observed, especially against RNA viruses. Equine picornavirus, equine rhinovirus and equine arteritis virus could not be propagated at all in 100 u/ml reIFN-gamma when 100 TCID(50) of infec...
Ma J, Zhang Z, Yao Q, Su C, Yin X, Wang X.Rev, an important accessory protein of equine infectious anaemia virus (EIAV), induces the nuclear export of incompletely spliced viral mRNAs. Rev is translated from the tat-rev mRNA through leaky scanning of the tat CUG. In this study, the function of the Kozak sequence at the beginning of the rev ORF was investigated. Deletion or attenuation of the Kozak sequence resulted in expression of an N-terminal 11 aa-truncated Rev in addition to WT Rev. Truncated Rev displayed weaker promotion of Gag expression and processing than WT Rev. Furthermore, EIAV rescued from an infectious molecular clon...
Montelaro RC, West M, Ivey M.Representative glycoproteins including fetuin, protein A, ovalbumin, alpha 1 acid glycoprotein, and the major glycoprotein of equine infectious anemia virus were labelled with 125I by the chloramine-T or Bolton-Hunter procedure and their binding to immobilized Con A or lentil lectin compared to untreated samples of each glycoprotein. Glycoprotein modification was no greater than one substituted residue per protein molecule. Yet the radioiodinated glycoproteins typically displayed only 0-50% of the lectin binding observed with untreated samples. These results indicate that lectin glycoprotein b...
Thomas RJ.An antigen for the gel diffusion test for equine infectious anaemia (EIA) was prepared from the spleen of a horse experimentally infected with the CQ strain of the virus. The antigen produced a single, distinct line of precipitation when tested against a range of known positive serums, and did not react with pre-inoculation and known negative serums. Extracts prepared from uninfected spleens displayed no reaction when similarly tested. Serum from 34 of 451 Queensland horses contained detectable levels of antibody to EIA virus. The positive serums were from horses in widely separated areas of t...
Hammond SA, Issel CJ, Montelaro RC.Equine immunological research is hindered by the lack of a simple yet reliable general protocol by which to assay CTL activity specific for viral or parasitic antigens. We present here the first comprehensive analysis of the parameters necessary to reliably culture equine T cells and to analyze the antigen specific cytolytic activity of T lymphocytes utilizing the equine infectious anemia virus (EIAV) infection of outbred ponies as a source for in vivo primed T lymphocytes. Effective long-term in vitro culture of equine T cells was determined to require minimally 200 U/ml of recombinant human ...
Darcel C.Diseases caused by lymphoid leukosis virus (LLV), a retrovirus, take a long time after infection to develop and have a wide variety of pathological manifestations. This long latent period is characteristic of 'persistent virus infections'. Disease produced by LLV infection and its underlying mechanisms is compared with 'persistent' infections caused by other retroviruses in birds and mammals of veterinary importance. The diseases considered for comparison are those caused by reticuloendotheliosis, feline leukaemia, bovine leukosis and equine infectious anaemia viruses. There are significant ch...
