Diagnosis of equine monocytic ehrlichiosis (Potomac horse fever) by indirect immunofluorescence.
Abstract: The recent establishment of a system for the continuous in vitro propagation of Ehrlichia risticii, the causative agent of equine monocytic ehrlichiosis (EME; synonym, Potomac horse fever), has facilitated the development of an indirect fluorescent antibody test for the diagnosis of this disease under laboratory and field conditions. The field diagnostic application of the test has aided in the recognition of the disease in 16 states of the United States and in 1 province of Canada. A limited epidemiologic study conducted between January and September 1985, in an area where the disease is known to be enzootic, revealed that conversion from seronegative to seropositive status is not always accompanied by clinical manifestations of the disease. Confirmatory findings in experimentally inoculated horses suggest the existence of clinically undetectable infections.
Publication Date: 1986-07-01 PubMed ID: 3525479
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- Journal Article
- Research Support
- Non-U.S. Gov't
- Clinical Findings
- Diagnosis
- Diagnostic Technique
- Disease Diagnosis
- Disease Etiology
- Disease Outbreaks
- Disease Surveillance
- Epidemiology
- Equine Diseases
- Equine Health
- Field Study
- Horses
- Immunofluorescence Assay
- Infection
- Infectious Disease
- Laboratory Methods
- Potomac Horse Fever
- Serodiagnosis
- Seroprevalence
- Veterinary Medicine
- Veterinary Research
Summary
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The study discusses the use of an indirect fluorescent antibody test to diagnose Potomac horse fever, a condition caused by the Ehrlichia risticii bacteria. The research also highlights that infection of the disease may occur without showing any clinical symptoms, as revealed through epidemiological studies and experimental inoculations.
Indirect Fluorescent Antibody Test for Diagnosis
- The researchers developed an indirect fluorescent antibody test to detect the presence of Ehrlichia risticii, the bacteria that causes Potomac horse fever also known as equine monocytic ehrlichiosis (EME).
- The process and success of this diagnostic test were made possible by the continuous in vitro propagation system for Ehrlichia risticii, which was recently established.
Epidemiological Study and Field Diagnostic Application
- The diagnostic test was applied on the field level to identify cases of the disease. This facilitated the identification of this disease in 16 U.S states as well as in a Canadian province.
- The researchers conducted a limited epidemiological study from January to September 1985, in an area where the disease is endemic.
Observations and Findings
- The study revealed that infection with Ehrlichia risticii does not necessarily result in visible clinical symptoms of the disease.
- The transition status from seronegative to seropositive i.e., from not having antibodies against Ehrlichia risticii in the blood, to having them, is not always accompanied by observable clinical signs of EME.
- The existence of ‘clinically undetectable infections’ was confirmed in experimentally inoculated horses, suggesting that horses can be infected without showing any signs of the disease.
Implications
- The research presents a robust diagnostic tool to detect Ehrlichia risticii infection in horses, which is crucial in effectively controlling the spread of the disease.
- The findings highlight the complexity of equine monocytic ehrlichiosis, indicating the need for further research on asymptomatic cases and their potential role in disease transmission.
Cite This Article
APA
Ristic M, Holland CJ, Dawson JE, Sessions J, Palmer J.
(1986).
Diagnosis of equine monocytic ehrlichiosis (Potomac horse fever) by indirect immunofluorescence.
J Am Vet Med Assoc, 189(1), 39-46.
Publication
Researcher Affiliations
MeSH Terms
- Animals
- Antigens, Bacterial / immunology
- Ehrlichia / immunology
- Fluorescent Antibody Technique
- Horse Diseases / diagnosis
- Horse Diseases / microbiology
- Horses / microbiology
- Rickettsiaceae Infections / diagnosis
- Rickettsiaceae Infections / immunology
- Rickettsiaceae Infections / veterinary
- Serologic Tests
Citations
This article has been cited 17 times.- Baird JD, Arroyo LG. Historical aspects of Potomac horse fever in Ontario (1924-2010). Can Vet J 2013 Jun;54(6):565-72.
- Gibson KE, Pastenkos G, Moesta S, Rikihisa Y. Neorickettsia risticii surface-exposed proteins: proteomics identification, recognition by naturally-infected horses, and strain variations. Vet Res 2011 Jun 2;42(1):71.
- Pritchard J. Alberta. Potomac horse fever. Can Vet J 1989 Mar;30(3):256.
- Mott J, Rikihisa Y, Zhang Y, Reed SM, Yu CY. Comparison of PCR and culture to the indirect fluorescent-antibody test for diagnosis of Potomac horse fever. J Clin Microbiol 1997 Sep;35(9):2215-9.
- Magnarelli LA, Anderson JF. Serologic evidence of canine and equine ehrlichiosis in northeastern United States. J Clin Microbiol 1993 Nov;31(11):2857-60.
- Pretzman CI, Rikihisa Y, Ralph D, Gordon JC, Bech-Nielsen S. Enzyme-linked immunosorbent assay for Potomac horse fever disease. J Clin Microbiol 1987 Jan;25(1):31-6.
- Rikihisa Y, Johnson GC, Burger CJ. Reduced immune responsiveness and lymphoid depletion in mice infected with Ehrlichia risticii. Infect Immun 1987 Sep;55(9):2215-22.
- Rikihisa Y, Pretzman CI, Johnson GC, Reed SM, Yamamoto S, Andrews F. Clinical, histopathological, and immunological responses of ponies to Ehrlichia sennetsu and subsequent Ehrlichia risticii challenge. Infect Immun 1988 Nov;56(11):2960-6.
- Dutta SK, Mattingly BL, Shankarappa B. Antibody response to Ehrlichia risticii and antibody reactivity to the component antigens in horses with induced Potomac horse fever. Infect Immun 1989 Oct;57(10):2959-62.
- Shankarappa B, Dutta SK, Sanusi J, Mattingly BL. Monoclonal antibody-mediated, immunodiagnostic competitive enzyme-linked immunosorbent assay for equine monocytic ehrlichiosis. J Clin Microbiol 1989 Jan;27(1):24-8.
- Hahn NE, Fletcher M, Rice RM, Kocan KM, Hansen JW, Hair JA, Barker RW, Perry BD. Attempted transmission of Ehrlichia risticii, causative agent of Potomac horse fever, by the ticks, Dermacentor variabilis, Rhipicephalus sanguineus, Ixodes scapularis and Amblyomma americanum. Exp Appl Acarol 1990 Jan;8(1-2):41-50.
- Thaker SR, Dutta SK, Adhya SL, Mattingly-Napier BL. Molecular cloning of Ehrlichia risticii and development of a gene probe for the diagnosis of Potomac horse fever. J Clin Microbiol 1990 Sep;28(9):1963-7.
- Dilbeck PM, Evermann JF, Crawford TB, Ward AC, Leathers CW, Holland CJ, Mebus CA, Logan LL, Rurangirwa FR, McGuire TC. Isolation of a previously undescribed rickettsia from an aborted bovine fetus. J Clin Microbiol 1990 Apr;28(4):814-6.
- Kaylor PS, Crawford TB, McElwain TF, Palmer GH. Passive transfer of antibody to Ehrlichia risticii protects mice from ehrlichiosis. Infect Immun 1991 Jun;59(6):2058-62.
- Biswas B, Mukherjee D, Mattingly-Napier BL, Dutta SK. Diagnostic application of polymerase chain reaction for detection of Ehrlichia risticii in equine monocytic ehrlichiosis (Potomac horse fever). J Clin Microbiol 1991 Oct;29(10):2228-33.
- Rikihisa Y. The tribe Ehrlichieae and ehrlichial diseases. Clin Microbiol Rev 1991 Jul;4(3):286-308.
- Ristic M, Holland CJ, Khondowe M. An overview of research on ehrlichiosis. Eur J Epidemiol 1991 May;7(3):246-52.
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