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J P Dubey - One of the best experts on this subject based on the ideXlab platform.
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testing the sarcocystis neurona vaccine using an Equine Protozoal Myeloencephalitis challenge model
Veterinary Parasitology, 2017Co-Authors: William J A Saville, Daniel K Howe, Jennifer K Morrow, J P Dubey, Antoinette E. Marsh, S M Reed, Robert O Keene, Jeffrey D WorkmanAbstract:Equine Protozoal Myeloencephalitis (EPM) is an important Equine neurologic disorder, and treatments for the disease are often unrewarding. Prevention of the disease is the most important aspect for EPM, and a killed vaccine was previously developed for just that purpose. Evaluation of the vaccine had been hampered by lack of post vaccination challenge. The purpose of this study was to determine if the vaccine could prevent development of clinical signs after challenge with Sarcocystis neurona sporocysts in an Equine challenge model. Seventy horses that were negative for antibodies to S. neurona and were neurologically normal were randomly assigned to vaccine or placebo groups and divided into short-term duration of immunity (study #1) and long-term duration of immunity (study #2) studies. S. neurona sporocysts used for the challenge were generated in the opossum/raccoon cycle isolate SN 37-R. Study #1 horses received an initial vaccination and a booster, and were challenged 34days post second vaccination. Study #2 horses received a vaccination and two boosters and were challenged 139days post third vaccination. All horses in study #1 developed neurologic signs (n=30) and there was no difference between the vaccinates and controls (P=0.7683). All but four horses in study #2 developed detectable neurologic deficits. The neurologic signs, although not statistically significant, were worse in the vaccinated horses (P=0.1559). In these two studies, vaccination with the S. neurona vaccine failed to prevent development of clinical neurologic deficits.
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sarcocyst development in raccoons procyon lotor inoculated with different strains of sarcocystis neurona culture derived merozoites
Journal of Parasitology, 2015Co-Authors: E L Dryburgh, J P Dubey, Antoinette E. Marsh, D K Howe, S M Reed, K E Bolten, W Pei, W J A SavilleAbstract:Abstract: Sarcocystis neurona is considered the major etiologic agent of Equine Protozoal Myeloencephalitis (EPM), a neurological disease in horses. Raccoon (Procyon lotor) is considered the most important intermediate host in the life cycle of S. neurona in the United States; S. neurona sarcocysts do mature in raccoon muscles, and raccoons also develop clinical signs simulating EPM. The focus of this study was to determine if sarcocysts would develop in raccoons experimentally inoculated with different host-derived strains of in vitro–cultivated S. neurona merozoites. Four raccoons were inoculated with strains derived from a raccoon, a sea otter, a cat, and a horse. Raccoon tissues were fed to laboratory-raised opossums (Didelphis virginiana), the definitive host of S. neurona. Intestinal scraping revealed sporocysts in opossums who received muscle tissue from raccoons inoculated with the raccoon-derived or the sea otter–derived isolates. These results demonstrate that sarcocysts can mature in raccoons ...
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an update on sarcocystis neurona infections in animals and Equine Protozoal Myeloencephalitis epm
Veterinary Parasitology, 2015Co-Authors: J P Dubey, Daniel K Howe, Martin Furr, Antoinette E. Marsh, S M Reed, W J A Saville, Michael E GriggAbstract:Equine Protozoal Myeloencephalitis (EPM) is a serious disease of horses, and its management continues to be a challenge for veterinarians. The protozoan Sarcocystis neurona is most commonly associated with EPM. S. neurona has emerged as a common cause of mortality in marine mammals, especially sea otters (Enhydra lutris). EPM-like illness has also been recorded in several other mammals, including domestic dogs and cats. This paper updates S. neurona and EPM information from the last 15 years on the advances regarding life cycle, molecular biology, epidemiology, clinical signs, diagnosis, treatment and control.
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prevalence of antibodies to sarcocystis neurona and neospora hughesi in horses from mexico
Parasite, 2013Co-Authors: Michelle R Yeargan, Cosme Alvaradoesquivel, J P Dubey, Daniel K HoweAbstract:Equine Protozoal Myeloencephalitis (EPM) is a debilitating disease of horses caused by Sarcocystis neurona and Neospora hughesi. Sera from 495 horses in Durango State, Mexico were tested for anti-Protozoal antibodies using enzyme-linked immunosorbent assays (ELISAs) based on major surface antigens of these two parasites. Antibodies to S. neurona were detected in 240 (48.5%) of the 495 horse sera tested with the rSnSAG2/4/3 trivalent ELISA. Multivariate analysis showed that exposure to S. neurona was associated with age, feeding grains and crops, and small herd size. Antibodies to N. hughesi were found in 15 (3.0%) of the 495 horse sera tested with the rNhSAG1 ELISA and confirmed by Western blot of N. hughesi tachyzoite antigen. This is the first report of S. neurona and N. hughesi exposure in horses in Mexico, and it affirms that EPM should be in the differential diagnosis for horses exhibiting signs of neurologic disease in this country.
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Prevalence of antibodies to
'EDP Sciences', 2013Co-Authors: Michelle R Yeargan, J P Dubey, Cosme Alvarado-esquivel, Daniel K HoweAbstract:Equine Protozoal Myeloencephalitis (EPM) is a debilitating disease of horses caused by Sarcocystis neurona and Neospora hughesi. Sera from 495 horses in Durango State, Mexico were tested for anti-Protozoal antibodies using enzyme-linked immunosorbent assays (ELISAs) based on major surface antigens of these two parasites. Antibodies to S. neurona were detected in 240 (48.5%) of the 495 horse sera tested with the rSnSAG2/4/3 trivalent ELISA. Multivariate analysis showed that exposure to S. neurona was associated with age, feeding grains and crops, and small herd size. Antibodies to N. hughesi were found in 15 (3.0%) of the 495 horse sera tested with the rNhSAG1 ELISA and confirmed by Western blot of N. hughesi tachyzoite antigen. This is the first report of S. neurona and N. hughesi exposure in horses in Mexico, and it affirms that EPM should be in the differential diagnosis for horses exhibiting signs of neurologic disease in this country
David S Lindsay - One of the best experts on this subject based on the ideXlab platform.
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Diclazuril treatment ineffective at preventing Equine Protozoal Myeloencephalitis relapse in established mouse model.
Journal of Immunology, 2017Co-Authors: Alayna Wagner, Sharon G. Witonsky, David S Lindsay, Leah Kasmark, Caroline M. LeethAbstract:The debilitating and potentially fatal neurologic disease, Equine Protozoal Myoencephalitis (EPM), is one of the most common neurologic diseases seen in the Equine population of the United States. Disease develops as a result of unintentional ingestion of the pathogenic parasite, Sarcocystis neurona . Treatment options consist of the anticoccidial drug Diclazuril and numerous other antiProtozoal drugs. Weeks to months after cessation of antiProtozoal drug treatment and corresponding neurologic improvement, horses may present with clinical disease symptoms again. Little is known whether this reoccurrence of symptoms is from relapse or reinfection. We sought to understand if relapse was possible following appropriate treatment with diclazuril, a commonly used medication for the treatment of EPM. Using a mouse model of Equine EPM, we subjected infected mice to treatment with or without diclazuril for 30 and 60 days. All untreated mice developed neurologic symptoms consistent with S. neurona infection within 30 days post infection. All diclazuril treated mice developed neurologic symptoms cessation of treatment. Cerebellum samples were examined for lesions characteristic of those associated with S. neurona infection and immunohistochemically for presences S. neurona . Sera immunoglobulin levels were analyzed to evaluate treatment’s effect on humoral immunity. In conclusion horses treated appropriately with 60 days of diclazuril may be at risk for relapse and more effective treatment options should be explored.
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Research Article Effects of Experimental Sarcocystis neurona-Induced Infection on Immunity in an Equine Model
2016Co-Authors: Rochelle S. Lewis, David S Lindsay, Siobhan P Ellison, Robert M Gogal, John J. Dascanio, Stephen R. Werre, Naveen Surendran, Meghan E. Breen, Bettina M. Heid, Frank M. AndrewsAbstract:License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Sarcocystis neurona is the most common cause of Equine Protozoal Myeloencephalitis (EPM), affecting 0.5–1 % horses in the United States during their lifetimes. The objective of this study was to evaluate the Equine immune responses in an experimentally induced Sarcocystis neurona infection model. Neurologic parameters were recorded prior to and throughout the 70-day study by blinded investigators. Recombinant SnSAG1 ELISA for serum and CSF were used to confirm and track disease progression. All experimentally infected horses displayed neurologic signs after infection. Neutrophils, monocytes, and lymphocytes from infecte
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Decoquinate Combined with Levamisole Reduce the Clinical Signs and Serum SAG 1, 5, 6 Antibodies in Horses with Suspected Equine Protozoal Myeloencephalitis
2012Co-Authors: Siobhan P Ellison, David S LindsayAbstract:Sarcocystis neurona is an apicomplexan parasite that can cause mortality in domestic and wild animals. It is an important cause of the neurological disease Equine Protozoal Myeloencephalitis (EPM) in the Americas. Different surface antigen (SAG) phenotypes have been observed for S. neurona, and not all isolates of S. neurona contain the genes (SnSAG) to encode all SAGs. Recent studies indicate the presence of antibodies to the antigens SAG 1 and SAG 5 are present in most cases of clinical disease. Using sera from horses with a presumptive diagnosis of EPM, we examined 141 horses for antibodies to disease-associated SAG phenotypes of S. neurona using an indirect ELISA employing recombinant SAG’s 1, 5, and 6 as antigens. An immunochromatic Sarcocystis neurona multiplex antibody detection kit (Centaur, Olathe, KS.) was evaluated for the rapid detection of antibodies to SAG 1, 5, and 6 of S. neurona. One hundred fortyone horses with a presumptive diagnosis of EPM were treated with a combination of decoquinate (0.5 mg/kg) and levamisole (1 mg/kg) in an oral paste, Oroquin-10 (Francks Compounding Labs, Ocala, Fl.), for 10 days and monitored for a treatment response. Successful treatment of EPM was determined by a reduction in clinical signs by clinical neurological examination and a reduction in antibodies 4-6 weeks post treatment. A reduction in clinical signs was seen in 132 (93.6%) horses and reduced antibody titers were observed in 126 (89.3%) horses. The detection of antibody against recombinant SAG’s 1, 5, 6, and a response to decoquinate/ levamisole identified horses with clinical EPM. The rapid detection of SAG phenotype using the multiplex antibody detection kit facilitated identification of significant antibodies and evaluation of a clinical response.
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immune response to sarcocystis neurona infection in naturally infected horses with Equine Protozoal Myeloencephalitis
Veterinary Parasitology, 2006Co-Authors: Jibing Yang, David S Lindsay, F M Andrews, Siobhan P Ellison, Robert M Gogal, Heather Norton, Daniel L Ward, Sharon G. WitonskyAbstract:Equine Protozoal Myeloencephalitis (EPM) is one of the most common neurologic diseases of horses in the United States. The primary etiologic agent is Sarcocystis neurona. Currently, there is limited knowledge regarding the protective or pathophysiologic immune response to S. neurona infection or the subsequent development of EPM. The objectives of this study were to determine whether S. neurona infected horses with clinical signs of EPM had altered or suppressed immune responses compared to neurologically normal horses and if blood sample storage would influence these findings. Twenty clinically normal horses and 22 horses with EPM, diagnosed by the presence of S. neurona specific antibodies in the serum and/or cerebrospinal (CSF) and clinical signs, were evaluated for differences in the immune cell subsets and function. Our results demonstrated that naturally infected horses had significantly (P < 0.05) higher percentages of CD4 T-lymphocytes and neutrophils (PMN) in separated peripheral blood leukocytes than clinically normal horses. Leukocytes from naturally infected EPM horses had significantly lower proliferation responses, as measured by thymidine incorporation, to a non-antigen specific mitogen than did clinically normal horses (P < 0.05). Currently, studies are in progress to determine the role of CD4 T cells in disease and protection against S. neurona in horses, as well as to determine the mechanism associated with suppressed in vitro proliferation responses. Finally, overnight storage of blood samples appears to alter T lymphocyte phenotypes and viability among leukocytes.
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penetration of Equine leukocytes by merozoites of sarcocystis neurona
Veterinary Parasitology, 2006Co-Authors: David S Lindsay, J P Dubey, Jibing Yang, Robert M Gogal, Sheila M Mitchell, Sharon G. WitonskyAbstract:Horses are considered accidental hosts for Sarcocystis neurona and they often develop severe neurological disease when infected with this parasite. Schizont stages develop in the central nervous system (CNS) and cause the neurological lesions associated with Equine Protozoal Myeloencephalitis. The present study was done to examine the ability of S. neurona merozoites to penetrate and develop in Equine peripheral blood leukocytes. These infected host cells might serve as a possible transport mechanism into the CNS. S. neurona merozoites penetrated Equine leukocytes within 5 min of co-culture. Infected leukocytes were usually monocytes. Infected leukocytes were present up to the final day of examination at 3 days. Up to three merozoites were present in an infected monocyte. No development to schizont stages was observed. All stages observed were in the host cell cytoplasm. We postulate that S. neurona merozoites may cross the blood brain barrier hidden inside leukocytes. Once inside the CNS these merozoites can egress and invade additional cells and cause encephalitis.
W J A Saville - One of the best experts on this subject based on the ideXlab platform.
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sarcocyst development in raccoons procyon lotor inoculated with different strains of sarcocystis neurona culture derived merozoites
Journal of Parasitology, 2015Co-Authors: E L Dryburgh, J P Dubey, Antoinette E. Marsh, D K Howe, S M Reed, K E Bolten, W Pei, W J A SavilleAbstract:Abstract: Sarcocystis neurona is considered the major etiologic agent of Equine Protozoal Myeloencephalitis (EPM), a neurological disease in horses. Raccoon (Procyon lotor) is considered the most important intermediate host in the life cycle of S. neurona in the United States; S. neurona sarcocysts do mature in raccoon muscles, and raccoons also develop clinical signs simulating EPM. The focus of this study was to determine if sarcocysts would develop in raccoons experimentally inoculated with different host-derived strains of in vitro–cultivated S. neurona merozoites. Four raccoons were inoculated with strains derived from a raccoon, a sea otter, a cat, and a horse. Raccoon tissues were fed to laboratory-raised opossums (Didelphis virginiana), the definitive host of S. neurona. Intestinal scraping revealed sporocysts in opossums who received muscle tissue from raccoons inoculated with the raccoon-derived or the sea otter–derived isolates. These results demonstrate that sarcocysts can mature in raccoons ...
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an update on sarcocystis neurona infections in animals and Equine Protozoal Myeloencephalitis epm
Veterinary Parasitology, 2015Co-Authors: J P Dubey, Daniel K Howe, Martin Furr, Antoinette E. Marsh, S M Reed, W J A Saville, Michael E GriggAbstract:Equine Protozoal Myeloencephalitis (EPM) is a serious disease of horses, and its management continues to be a challenge for veterinarians. The protozoan Sarcocystis neurona is most commonly associated with EPM. S. neurona has emerged as a common cause of mortality in marine mammals, especially sea otters (Enhydra lutris). EPM-like illness has also been recorded in several other mammals, including domestic dogs and cats. This paper updates S. neurona and EPM information from the last 15 years on the advances regarding life cycle, molecular biology, epidemiology, clinical signs, diagnosis, treatment and control.
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accurate antemortem diagnosis of Equine Protozoal Myeloencephalitis epm based on detecting intrathecal antibodies against sarcocystis neurona using the snsag2 and snsag4 3 elisas
Journal of Veterinary Internal Medicine, 2013Co-Authors: S M Reed, Michelle R Yeargan, Daniel K Howe, Jennifer K Morrow, Amy Graves, Martin Furr, W J A Saville, R J Mackay, A L Johnson, N M WilliamsAbstract:Background Recent work demonstrated the value of antigen-specific antibody indices (AI and C-value) to detect intrathecal antibody production against Sarcocystis neurona for antemortem diagnosis of Equine Protozoal Myeloencephalitis (EPM). Objectives The study was conducted to assess whether the antigen-specific antibody indices can be reduced to a simple serum : cerebrospinal fluid (CSF) titer ratio to achieve accurate EPM diagnosis. Animals Paired serum and CSF samples from 128 horses diagnosed by postmortem examination. The sample set included 44 EPM cases, 35 cervical-vertebral malformation (CVM) cases, 39 neurologic cases other than EPM or CVM, and 10 non-neurologic cases. Methods Antibodies against S. neurona were measured in serum and CSF pairs using the SnSAG2 and SnSAG4/3 (SnSAG2, 4/3) ELISAs, and the ratio of each respective serum titer to CSF titer was determined. Likelihood ratios and diagnostic sensitivity and specificity were calculated based on serum titers, CSF titers, and serum : CSF titer ratios. Results Excellent diagnostic sensitivity and specificity was obtained from the SnSAG2, 4/3 serum : CSF titer ratio. Sensitivity and specificity of 93.2 and 81.1%, respectively, were achieved using a ratio cutoff of ≤100, whereas sensitivity and specificity were 86.4 and 95.9%, respectively, if a more rigorous cutoff of ≤50 was used. Antibody titers in CSF also provided good diagnostic accuracy. Serum antibody titers alone yielded much lower sensitivity and specificity. Conclusions and Clinical Importance The study confirms the value of detecting intrathecal antibody production for antemortem diagnosis of EPM, and they further show that the antigen-specific antibody indices can be reduced in practice to a simple serum : CSF titer ratio.
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risk factors for owner reported occurrence of Equine Protozoal Myeloencephalitis in the us Equine population
Journal of Veterinary Internal Medicine, 2008Co-Authors: Paul S Morley, W J A Saville, Josie L Traubdargatz, Katharine M Benedict, L D Voelker, Bruce A WagnerAbstract:Background: Equine Protozoal Myeloencephalitis (EPM) is a serious and often fatal neurologic disease of horses, but few studies have investigated risk factors. Objectives: To evaluate operation- and individual-level factors associated with likelihood of the occurrence of EPM. Animals: Data were collected as part of a study of the US Equine industry from 1,178 operations representing 83.9% of horses and 51.6% of operations with ≥3 horses in 28 states. Methods: Probability-based sampling was used to enroll representative operations in a cross-sectional study. Interviews were conducted to collect information regarding health and management of horses. A nested case-control study was used to investigate risk factors among individual horses. Interview data were combined with climate data, human population density, and opossum regional ecology categories. Data were analyzed using logistic regression to identify risk factors for the occurrence of EPM. Results: Owners reported that 95% of EPM cases included in this study were diagnosed by veterinarians. Variables associated with EPM occurrence on premises included opossum regional ecology, reported exposure to small wildlife, climate, terrain, housing, choice of bedding material, method of storing feeds, Equine stocking density, and primary use of horses. Among individual horses, age was most strongly associated with disease risk. Associations also were identified with sex, breed, primary use, and participation in competitions. Conclusions and Clinical Importance: Because the risk of EPM occurrence on operations is closely tied to factors that impact exposure to opossums, their feces, and their environment, controlling these exposures may be important in preventing the occurrence of EPM.
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epidemiology of sarcocystis neurona infections in domestic cats felis domesticus and its association with Equine Protozoal Myeloencephalitis epm case farms and feral cats from a mobile spay and neuter clinic
Veterinary Parasitology, 2003Co-Authors: J F Stanek, J P Dubey, David S Lindsay, Roger W Stich, C J Njoku, S M Reed, L M Schmall, G K Johnson, B M Lafave, W J A SavilleAbstract:Abstract Equine Protozoal Myeloencephalitis (EPM) is a serious neurologic disease in the horse most commonly caused by Sarcocystis neurona . The domestic cat ( Felis domesticus ) is an intermediate host for S. neurona . In the present study, nine farms, known to have prior clinically diagnosed cases of EPM and a resident cat population were identified and sampled accordingly. In addition to the farm cats sampled, samples were also collected from a mobile spay and neuter clinic. Overall, serum samples were collected in 2001 from 310 cats, with samples including barn, feral and inside/outside cats. Of these 310 samples, 35 were from nine horse farms. Horse serum samples were also collected and traps were set for opossums at each of the farms. The S. neurona direct agglutination test (SAT) was used for both the horse and cat serum samples (1:25 dilution). Fourteen of 35 (40%) cats sampled from horse farms had circulating S. neurona agglutinating antibodies. Twenty-seven of the 275 (10%) cats from the spay/neuter clinic also had detectable S. neurona antibodies. Overall, 115 of 123 (93%) horses tested positive for anti- S. neurona antibodies, with each farm having greater than a 75% exposure rate among sampled horses. Twenty-one opossums were trapped on seven of the nine farms. Eleven opossums had Sarcocystis sp. sporocysts, six of them were identified as S. neurona sporocysts based on bioassays in γ-interferon gene knockout mice with each opossum representing a different farm. Demonstration of S. neurona agglutinating antibodies in domestic and feral cats corroborates previous research demonstrating feral cats to be naturally infected, and also suggests that cats can be frequently infected with S. neurona and serve as one of several natural intermediate hosts for S. neurona .
S M Reed - One of the best experts on this subject based on the ideXlab platform.
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testing the sarcocystis neurona vaccine using an Equine Protozoal Myeloencephalitis challenge model
Veterinary Parasitology, 2017Co-Authors: William J A Saville, Daniel K Howe, Jennifer K Morrow, J P Dubey, Antoinette E. Marsh, S M Reed, Robert O Keene, Jeffrey D WorkmanAbstract:Equine Protozoal Myeloencephalitis (EPM) is an important Equine neurologic disorder, and treatments for the disease are often unrewarding. Prevention of the disease is the most important aspect for EPM, and a killed vaccine was previously developed for just that purpose. Evaluation of the vaccine had been hampered by lack of post vaccination challenge. The purpose of this study was to determine if the vaccine could prevent development of clinical signs after challenge with Sarcocystis neurona sporocysts in an Equine challenge model. Seventy horses that were negative for antibodies to S. neurona and were neurologically normal were randomly assigned to vaccine or placebo groups and divided into short-term duration of immunity (study #1) and long-term duration of immunity (study #2) studies. S. neurona sporocysts used for the challenge were generated in the opossum/raccoon cycle isolate SN 37-R. Study #1 horses received an initial vaccination and a booster, and were challenged 34days post second vaccination. Study #2 horses received a vaccination and two boosters and were challenged 139days post third vaccination. All horses in study #1 developed neurologic signs (n=30) and there was no difference between the vaccinates and controls (P=0.7683). All but four horses in study #2 developed detectable neurologic deficits. The neurologic signs, although not statistically significant, were worse in the vaccinated horses (P=0.1559). In these two studies, vaccination with the S. neurona vaccine failed to prevent development of clinical neurologic deficits.
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sarcocyst development in raccoons procyon lotor inoculated with different strains of sarcocystis neurona culture derived merozoites
Journal of Parasitology, 2015Co-Authors: E L Dryburgh, J P Dubey, Antoinette E. Marsh, D K Howe, S M Reed, K E Bolten, W Pei, W J A SavilleAbstract:Abstract: Sarcocystis neurona is considered the major etiologic agent of Equine Protozoal Myeloencephalitis (EPM), a neurological disease in horses. Raccoon (Procyon lotor) is considered the most important intermediate host in the life cycle of S. neurona in the United States; S. neurona sarcocysts do mature in raccoon muscles, and raccoons also develop clinical signs simulating EPM. The focus of this study was to determine if sarcocysts would develop in raccoons experimentally inoculated with different host-derived strains of in vitro–cultivated S. neurona merozoites. Four raccoons were inoculated with strains derived from a raccoon, a sea otter, a cat, and a horse. Raccoon tissues were fed to laboratory-raised opossums (Didelphis virginiana), the definitive host of S. neurona. Intestinal scraping revealed sporocysts in opossums who received muscle tissue from raccoons inoculated with the raccoon-derived or the sea otter–derived isolates. These results demonstrate that sarcocysts can mature in raccoons ...
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an update on sarcocystis neurona infections in animals and Equine Protozoal Myeloencephalitis epm
Veterinary Parasitology, 2015Co-Authors: J P Dubey, Daniel K Howe, Martin Furr, Antoinette E. Marsh, S M Reed, W J A Saville, Michael E GriggAbstract:Equine Protozoal Myeloencephalitis (EPM) is a serious disease of horses, and its management continues to be a challenge for veterinarians. The protozoan Sarcocystis neurona is most commonly associated with EPM. S. neurona has emerged as a common cause of mortality in marine mammals, especially sea otters (Enhydra lutris). EPM-like illness has also been recorded in several other mammals, including domestic dogs and cats. This paper updates S. neurona and EPM information from the last 15 years on the advances regarding life cycle, molecular biology, epidemiology, clinical signs, diagnosis, treatment and control.
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accurate antemortem diagnosis of Equine Protozoal Myeloencephalitis epm based on detecting intrathecal antibodies against sarcocystis neurona using the snsag2 and snsag4 3 elisas
Journal of Veterinary Internal Medicine, 2013Co-Authors: S M Reed, Michelle R Yeargan, Daniel K Howe, Jennifer K Morrow, Amy Graves, Martin Furr, W J A Saville, R J Mackay, A L Johnson, N M WilliamsAbstract:Background Recent work demonstrated the value of antigen-specific antibody indices (AI and C-value) to detect intrathecal antibody production against Sarcocystis neurona for antemortem diagnosis of Equine Protozoal Myeloencephalitis (EPM). Objectives The study was conducted to assess whether the antigen-specific antibody indices can be reduced to a simple serum : cerebrospinal fluid (CSF) titer ratio to achieve accurate EPM diagnosis. Animals Paired serum and CSF samples from 128 horses diagnosed by postmortem examination. The sample set included 44 EPM cases, 35 cervical-vertebral malformation (CVM) cases, 39 neurologic cases other than EPM or CVM, and 10 non-neurologic cases. Methods Antibodies against S. neurona were measured in serum and CSF pairs using the SnSAG2 and SnSAG4/3 (SnSAG2, 4/3) ELISAs, and the ratio of each respective serum titer to CSF titer was determined. Likelihood ratios and diagnostic sensitivity and specificity were calculated based on serum titers, CSF titers, and serum : CSF titer ratios. Results Excellent diagnostic sensitivity and specificity was obtained from the SnSAG2, 4/3 serum : CSF titer ratio. Sensitivity and specificity of 93.2 and 81.1%, respectively, were achieved using a ratio cutoff of ≤100, whereas sensitivity and specificity were 86.4 and 95.9%, respectively, if a more rigorous cutoff of ≤50 was used. Antibody titers in CSF also provided good diagnostic accuracy. Serum antibody titers alone yielded much lower sensitivity and specificity. Conclusions and Clinical Importance The study confirms the value of detecting intrathecal antibody production for antemortem diagnosis of EPM, and they further show that the antigen-specific antibody indices can be reduced in practice to a simple serum : CSF titer ratio.
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epidemiology of sarcocystis neurona infections in domestic cats felis domesticus and its association with Equine Protozoal Myeloencephalitis epm case farms and feral cats from a mobile spay and neuter clinic
Veterinary Parasitology, 2003Co-Authors: J F Stanek, J P Dubey, David S Lindsay, Roger W Stich, C J Njoku, S M Reed, L M Schmall, G K Johnson, B M Lafave, W J A SavilleAbstract:Abstract Equine Protozoal Myeloencephalitis (EPM) is a serious neurologic disease in the horse most commonly caused by Sarcocystis neurona . The domestic cat ( Felis domesticus ) is an intermediate host for S. neurona . In the present study, nine farms, known to have prior clinically diagnosed cases of EPM and a resident cat population were identified and sampled accordingly. In addition to the farm cats sampled, samples were also collected from a mobile spay and neuter clinic. Overall, serum samples were collected in 2001 from 310 cats, with samples including barn, feral and inside/outside cats. Of these 310 samples, 35 were from nine horse farms. Horse serum samples were also collected and traps were set for opossums at each of the farms. The S. neurona direct agglutination test (SAT) was used for both the horse and cat serum samples (1:25 dilution). Fourteen of 35 (40%) cats sampled from horse farms had circulating S. neurona agglutinating antibodies. Twenty-seven of the 275 (10%) cats from the spay/neuter clinic also had detectable S. neurona antibodies. Overall, 115 of 123 (93%) horses tested positive for anti- S. neurona antibodies, with each farm having greater than a 75% exposure rate among sampled horses. Twenty-one opossums were trapped on seven of the nine farms. Eleven opossums had Sarcocystis sp. sporocysts, six of them were identified as S. neurona sporocysts based on bioassays in γ-interferon gene knockout mice with each opossum representing a different farm. Demonstration of S. neurona agglutinating antibodies in domestic and feral cats corroborates previous research demonstrating feral cats to be naturally infected, and also suggests that cats can be frequently infected with S. neurona and serve as one of several natural intermediate hosts for S. neurona .
Antoinette E. Marsh - One of the best experts on this subject based on the ideXlab platform.
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testing the sarcocystis neurona vaccine using an Equine Protozoal Myeloencephalitis challenge model
Veterinary Parasitology, 2017Co-Authors: William J A Saville, Daniel K Howe, Jennifer K Morrow, J P Dubey, Antoinette E. Marsh, S M Reed, Robert O Keene, Jeffrey D WorkmanAbstract:Equine Protozoal Myeloencephalitis (EPM) is an important Equine neurologic disorder, and treatments for the disease are often unrewarding. Prevention of the disease is the most important aspect for EPM, and a killed vaccine was previously developed for just that purpose. Evaluation of the vaccine had been hampered by lack of post vaccination challenge. The purpose of this study was to determine if the vaccine could prevent development of clinical signs after challenge with Sarcocystis neurona sporocysts in an Equine challenge model. Seventy horses that were negative for antibodies to S. neurona and were neurologically normal were randomly assigned to vaccine or placebo groups and divided into short-term duration of immunity (study #1) and long-term duration of immunity (study #2) studies. S. neurona sporocysts used for the challenge were generated in the opossum/raccoon cycle isolate SN 37-R. Study #1 horses received an initial vaccination and a booster, and were challenged 34days post second vaccination. Study #2 horses received a vaccination and two boosters and were challenged 139days post third vaccination. All horses in study #1 developed neurologic signs (n=30) and there was no difference between the vaccinates and controls (P=0.7683). All but four horses in study #2 developed detectable neurologic deficits. The neurologic signs, although not statistically significant, were worse in the vaccinated horses (P=0.1559). In these two studies, vaccination with the S. neurona vaccine failed to prevent development of clinical neurologic deficits.
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sarcocyst development in raccoons procyon lotor inoculated with different strains of sarcocystis neurona culture derived merozoites
Journal of Parasitology, 2015Co-Authors: E L Dryburgh, J P Dubey, Antoinette E. Marsh, D K Howe, S M Reed, K E Bolten, W Pei, W J A SavilleAbstract:Abstract: Sarcocystis neurona is considered the major etiologic agent of Equine Protozoal Myeloencephalitis (EPM), a neurological disease in horses. Raccoon (Procyon lotor) is considered the most important intermediate host in the life cycle of S. neurona in the United States; S. neurona sarcocysts do mature in raccoon muscles, and raccoons also develop clinical signs simulating EPM. The focus of this study was to determine if sarcocysts would develop in raccoons experimentally inoculated with different host-derived strains of in vitro–cultivated S. neurona merozoites. Four raccoons were inoculated with strains derived from a raccoon, a sea otter, a cat, and a horse. Raccoon tissues were fed to laboratory-raised opossums (Didelphis virginiana), the definitive host of S. neurona. Intestinal scraping revealed sporocysts in opossums who received muscle tissue from raccoons inoculated with the raccoon-derived or the sea otter–derived isolates. These results demonstrate that sarcocysts can mature in raccoons ...
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an update on sarcocystis neurona infections in animals and Equine Protozoal Myeloencephalitis epm
Veterinary Parasitology, 2015Co-Authors: J P Dubey, Daniel K Howe, Martin Furr, Antoinette E. Marsh, S M Reed, W J A Saville, Michael E GriggAbstract:Equine Protozoal Myeloencephalitis (EPM) is a serious disease of horses, and its management continues to be a challenge for veterinarians. The protozoan Sarcocystis neurona is most commonly associated with EPM. S. neurona has emerged as a common cause of mortality in marine mammals, especially sea otters (Enhydra lutris). EPM-like illness has also been recorded in several other mammals, including domestic dogs and cats. This paper updates S. neurona and EPM information from the last 15 years on the advances regarding life cycle, molecular biology, epidemiology, clinical signs, diagnosis, treatment and control.
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sarcocystis neurona reacting antibodies in missouri feral domestic cats felis domesticus and their role as an intermediate host
Parasitology Research, 2002Co-Authors: H O Turay, Bradd C. Barr, A Caldwell, K R Branson, M K R Cockrell, Antoinette E. MarshAbstract:Sarcocystis neurona is the parasite associated with Equine Protozoal Myeloencephalitis (EPM). Recently, cats (Felis domesticus) have been implicated as a potential intermediate host in the life cycle of S. neurona. This study was initiated to determine whether cats have antibodies that react to S. neurona antigens similar to antibodies from horses with EPM, and to evaluate the role of cats as intermediate hosts in the parasite's life cycle. Nine feral cats were used for analysis. Only one had antibodies reacting to S. neurona antigens. Muscle tissue from this cat, with detectable sarcocysts in the tongue, was fed to an opossum (Didelphis virginiana). The opossum shed sporocysts, which were then fed to gamma-interferon receptor knockout mice. Histopathology, immunohistochemistry, parasite isolation and molecular analysis were used to examine the pathology and associated parasites in the mice. The study suggests that the domestic cat can serve as an intermediate host to S. neurona or a S. neurona-like organsim.
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characterization of a sarcocystis neurona isolate from a missouri horse with Equine Protozoal Myeloencephalitis
Veterinary Parasitology, 2001Co-Authors: Antoinette E. Marsh, Philip J Johnson, Jose A Ramosvara, Gayle C JohnsonAbstract:Abstract Little information is available about antigenic variation of Sarcocystis neurona isolated from horses with Equine Protozoal Myeloencephalitis, nor is there much information available on the specific antibody pattern to S. neurona antigens of horses from different geographic regions where S. neurona isolates have been obtained. This communication reports on the characterization of a new S. neurona isolate, SN-MU1. The isolate was obtained from a 3-year old Thoroughbred that had asymmetrical neurological signs and localized skeletal muscle atrophy. This S. neurona isolate is similar to other S. neurona isolates by molecular analysis of the internal transcribed spacer (ITS-1) region and a random-amplified polymorphic DNA marker, but is phenotypically distinct from the other S. neurona isolates examined. Evaluation of the antibodies from the affected horse and immunohistochemical results suggested that antigenic variation of S. neurona can result in variable antibody–antigen reactivity observed in the S. neurona immunoblot test.