Ehrlichia is a genus of bacteria that can infect horses, leading to a condition known as equine ehrlichiosis. This disease is transmitted primarily through tick bites and is characterized by symptoms such as fever, lethargy, and edema. Ehrlichia affects the immune system by targeting white blood cells, which can result in various clinical manifestations depending on the severity of the infection. Diagnosis often involves serological tests and polymerase chain reaction (PCR) to detect the presence of the bacteria. Treatment typically includes the administration of antibiotics, such as tetracyclines. This page compiles peer-reviewed research studies and scholarly articles that explore the pathogenesis, epidemiology, diagnosis, and treatment of Ehrlichia infections in horses.
Dutta SK, Mattingly BL, Shankarappa B.The antibody response and the antibody reactivity to component antigens of Ehrlichia risticii were studied in horses with induced Potomac horse fever. These horses had no detectable antibodies to E. risticii in their preinoculation (PrI) sera by indirect fluorescent-antibody assay and enzyme-linked immunosorbent assay (ELISA). All the horses exhibited typical disease features following experimental infection and responded with specific antibodies, as measured by ELISA and indirect fluorescent-antibody assay. A primary antibody response was detected in 70% of the horses, while a secondary-type ...
Palmer JE, Whitlock RH, Benson CE.Equine ehrlichial colitis was experimentally induced in 18 ponies, using Ehrlichia risticii-infected blood. Four ponies (group 1) were treated with oxytetracycline (6.6 mg/kg of body weight, IV, q 12 h), beginning 14 hours before inoculation and continuing for 5 days after inoculation. Four additional ponies (group 2) were treated similarly for 10 days after inoculation. The remaining 10 ponies were used as nontreated, infected controls. Clinical disease was delayed in 3 group-1 ponies and in 4 group-2 ponies. Protective immunity developed in the remaining pony that did not develop clinical di...
Pretzman CI, Rikihisa Y, Ralph D, Gordon JC, Bech-Nielsen S.An enzyme-linked immunosorbent assay (ELISA) for immunoglobulin G (IgG) and IgM in natural and experimental infections of equids with Ehrlichia risticii was developed. Ehrlichial organisms purified from an infected mouse macrophage cell line were used as the antigen. IgM was separated from serum IgG by the expedient of spun-column chromatography, allowing the use of an indirect ELISA for quantitation of both IgG and IgM in the test sera. Among 16 paired sera from horses exhibiting clinical signs of Potomac horse fever, 8 were positive by the indirect fluorescent-antibody test (IFA), 11 were po...
Dutta SK, Myrup AC, Rice RM, Robl MG, Hammond RC.Potomac horse fever, a recently recognized disease of equines, characterized by high fever, leukopenia, and a profuse diarrhea, was studied for its etiology. An Ehrlichia organism was isolated in equine macrophage-fibroblast cell cultures and mouse macrophage cell cultures from the mononuclear cells of blood of infected horses. The agent was continuously propagated in mouse macrophage cell cultures. The organism multiplied in the cytoplasm of mouse macrophage cells and was identified by Giemsa staining, acridine orange staining, and by indirect immunofluorescence with convalescent sera from in...
Lewis GE, Huxsoll DL, Ristic M, Johnson AJ.Dogs (German Shepherd Dogs and Beagles), cates, rhesus macaques (Macaca mulatta), and baboons (Papio anubis) were inoculated with Whrlichia equi, the etiologic agent of equine ehrlichiosis. Within 3 to 7 days after inoculation, morulae were observed in the eosinophils of cats, neurtrophils of macaques and baboons, and in both neutrophils and eosinophils of dogs. The severe disease produced in horses by this agent was not a feature of E equi infection in dogs, cats, macaques, and baboons. However, a susceptible horse, inoculated with the pooled blood of 2 infected macaques, developed severe cli...
Atwill ER, Mohammed HO, Lopez JW, McCulloch CE, Dubovi EJ.To locate counties within New York state with a high seroprevalence among the equine population, to determine host, management, and environmental factors that were associated with seropositivity to Ehrlichia risticii, and to determine evidence for arthropod- or helminth-mediated transmission of E risticii to horses. Methods: Cross-sectional study. Methods: A random sample of 3,000 of the 39,000 equine operations in New York state was selected, and 2,587 horses from 511 operations were tested. Methods: Blood samples were collected from horses and tested for seropositivity, using the indirect fl...
Levi O, Waner T, Baneth G, Keysary A, Bruchim Y, Silverman J, Harrus S.The presence of reacting antibodies to Anaplasma phagocytophilum has previously been demonstrated in Israel, both in humans and the golden jackal (Canis aureus syriacus). This study was undertaken to determine the seroprevalence of A. phagocytophilum antibodies in two additional potential hosts, domestic dogs and horses in order to investigate the possibility of exposure to the organism in Israel. Of 195 dogs tested, 9% were seroreactive with A. phagocytophilum antigen and 30% were seroreactive to Ehrlichia canis. Twenty-nine percent of the dogs seropositive for E. canis were also reactive to ...
Palmer JE, Whitlock RH, Benson CE.Equine ehrlichial colitis was experimentally induced in 18 ponies, using Ehrlichia risticii-infected blood. Four ponies (group 1) were treated with oxytetracycline (6.6 mg/kg of body weight, IV, q 12 h), beginning 14 hours before inoculation and continuing for 5 days after inoculation. Four additional ponies (group 2) were treated similarly for 10 days after inoculation. The remaining 10 ponies were used as nontreated, infected controls. Clinical disease was delayed in 3 group-1 ponies and in 4 group-2 ponies. Protective immunity developed in the remaining pony that did not develop clinical di...
Franzén P, Berg AL, Aspan A, Gunnarsson A, Pringle J.A 19-year-old horse that was one of a group of six horses infected experimentally with Anaplasma phagocytophilum for a study of the pathogenesis of equine granulocytic ehrlichiosis died suddenly two days after first showing clinical signs of disease. The clinical signs and laboratory findings observed before its death were similar to all those of the other infected horses, and to previous reports of this disease. A postmortem examination revealed widespread haemorrhaging in its internal organs, and vasculitis and thrombosis in the kidneys. These changes are consistent with disseminated intrava...
Miranda J, Mattar S.Anaplasma and Ehrlichia species are important tick-borne pathogens that cause disease in cattle, dogs, horses and humans; with little information available about these agents in Colombia. The aim of this study was to provide molecular evidence for the presence of Anaplasma sp. and Ehrlichia sp. species in ticks collected from horses, dogs and cattle in Cordoba, Colombia. In this study, 1.105 ticks were removed from 226 zebu cattle (Bos indicus), 87 dogs (Canis lupus familiaris) and 19 horses (Equus caballus), from different localities of Cordoba. Ticks were identified taxonomically and PCR ass...
Martínez Díaz HC, Gil-Mora J, Betancourt-Ruiz P, Silva-Ramos CR, Matiz-González JM, Villalba-Perez MA, Ospina-Pinto MC, Ramirez-Hernández A....Some hard ticks' species can act as vectors of a wide variety of pathogens of human and animal importance such as Anaplasma, Ehrlichia and Rickettsia spp. In Colombia, a total of forty-six tick species have been described, and some of them have been implicated as vectors of some infectious agents. The department of Cauca is one of the thirty-two departments of Colombia. Most of its population lives in rural areas and depends on agriculture as the main economic activity, favoring exposure to ticks and tick-borne pathogens. Thus, the present study aimed to determine the tick species and tick-bor...
