Abstract: Equine clinical larval cyathostominosis is caused by simultaneous mass emergence of previously inhibited larvae from the mucosa of the colon. Clinical signs include diarrhoea, colic, weight loss and malaise, and in up to 50% of cases, the disease results in death. Cyathostominae spend a large part of their life cycle as larval stages in the intestinal mucosa. Definitive diagnosis is difficult due to the lack of diagnostic methods for pre-patent infection. In the present study, the enzyme-linked immunosorbent assay (ELISA) was used to investigate isotype responses to larval cyathostominae somatic antigen. Measurement of anti-larval IgG(T) responses appeared to have the most immunodiagnostic potential. An increase in IgG(T) response was detected to crude larval antigen by 5 weeks post-infection (PI) in individual infected ponies. Subsequently, IgG(T) responses to larval and adult somatic extracts were examined by Western blotting using sera from experimentally-infected horses and helminth-naive animals (n=6). Two antigen complexes, designated A and B, in larval somatic antigen were recognised specifically by the infected animals by 7 weeks PI. Sera taken from 23 endemically-infected animals, whose cyathostominae burdens had been enumerated, were also used to identify putative diagnostic antigens. Eighteen horses had positive mucosal worm burdens (range 723-3,595,725) and all but two of these animals had serum IgG(T) antibody specific to either complex. Moreover, IgG(T) responses specific to antigen complexes A and B were absent in all five parasite negative horses that were tested. Serum IgG(T) responses to either of the two complexes were identified in five clinical cases tested. IgG(T) responses to adult antigen somatic extracts were more heterogeneous, with no clear pattern between experimentally-infected ponies and helminth-free controls. The results indicate that increases in serum IgG(T) to mucosal larvae occur in the pre-patent period and that two antigenic complexes within somatic preparations of these stages have immunodiagnostic potential.
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This research investigates equine clinical larval cyathostominosis in horses. Specifically, it studies the possible immunodiagnostic potential of increases in serum IgG(T) in response to this infection.
Background
Equine clinical larval cyathostominosis is a serious infection in horses, caused by a mass emergence of inhibited larvae from the colon’s mucosa. It results in clinical signs like diarrhoea, colic, weight loss, malaise, and in severe cases, may lead to death.
Cyathostominae, the worms causing this infection, spend a significant part of their life cycle as larval stages in the intestinal mucosa of the horse.
The diagnosis of this infection is challenging due to the lack of diagnostic methods for the early stages of infection.
Methodology
The study used the enzyme-linked immunosorbent assay (ELISA) to investigate isotype responses to larval cyathostominae somatic antigen. This antigen is produced by the larvae of cyathostominae present in the horse’s intestine.
Two antigen complexes, A and B, were specifically recognised by infected animals. These complexes were identified in somatic preparations of these larval stages – confirming their potential for immunodiagnosis.
Results
An increase in IgG(T) response, part of the immune response, was detected to larval antigen 5 weeks post-infection in individual infected ponies. The IgG(T) response refers to a subtype of immunoglobulin G (a type of antibody) that is specific to the antigen.
IgG(T) responses were subsequently examined using Western blotting, a common method for detection of specific proteins, in serum samples from both experimentally infected horses and worms naive animals.
In a sample of 23 endemically-infected animals, all but two of those with positive mucosal worm burdens (ranging from 723 to 3,595,725) had serum IgG(T) antibodies specific to either complex A or B.
All five parasite-negative tested horses lacked IgG(T) responses specific to antigen complexes A and B.
Five clinical cases tested showed IgG(T) responses to either of the two complexes.
IgG(T) responses to adult antigen somatic extracts were more heterogeneous with no clear pattern between experimentally infected ponies and helminth-free controls.
Conclusion
The results suggest that increases in serum IgG(T) occur in the pre-patent (asymptomatic) stage of infection, indicating their potential use in early detection and diagnosis of the infection.
Two antigenic complexes within somatic preparations of larval stages have been identified as having immunodiagnostic potential.
Cite This Article
APA
Dowdall SM, Matthews JB, Mair T, Murphy D, Love S, Proudman CJ.
(2002).
Antigen-specific IgG(T) responses in natural and experimental cyathostominae infection in horses.
Vet Parasitol, 106(3), 225-242.
https://doi.org/10.1016/s0304-4017(02)00085-7
Department of Veterinary Clinical Science, Faculty of Veterinary Science, University of Liverpool, Leahurst, South Wirral CH64 7TE, UK. sdowdall@liverpool.ac.uk
Louro M, Kuzmina TA, Bredtmann CM, Diekmann I, de Carvalho LMM, von Samson-Himmelstjerna G, Krücken J. Genetic variability, cryptic species and phylogenetic relationship of six cyathostomin species based on mitochondrial and nuclear sequences. Sci Rep 2021 Apr 15;11(1):8245.
Seeber PA, Kuzmina TA, Greenwood AD, East ML. Effects of life history stage and climatic conditions on fecal egg counts in plains zebras (Equus quagga) in the Serengeti National Park. Parasitol Res 2020 Oct;119(10):3401-3413.
Paz-Silva A, Francisco R, Rodríguez I, Francisco I, Cazapal-Monteiro CF, Arias MS, Suárez JL, Sánchez-Andrade R. Isolation of potentially useful antigens from cyathostomin third-stage larvae by using a fast protein liquid chromatography one-step method. Clin Vaccine Immunol 2011 Sep;18(9):1462-6.