Tick-borne diseases in horses refer to illnesses transmitted by tick vectors, affecting equine health through various pathogens. These diseases can lead to a range of clinical symptoms, including fever, lethargy, and lameness, depending on the specific pathogen involved. Common tick-borne diseases affecting horses include Lyme disease, equine piroplasmosis, and anaplasmosis. Diagnosis often involves serological tests, PCR assays, and clinical evaluation. Understanding the ecology of ticks and their interaction with horses is essential for managing and preventing these diseases. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, pathogenesis, diagnosis, and management of tick-borne diseases in horses.
Moltmann UG, Mehlhorn H, Schein E, Rehbein G, Voigt WP, Zweygarth E.The development of Babesia equi (Piroplasmia) in the vertebrate host was studied by electron microscopy. The tick-borne sporozoites initiated an exoerythrocytic schizogony in lymphocytes in vivo and in vitro. In lymphocyte cultures the schizonts of B. equi lay as fissured bodies directly within the host cell forming numerous cytomeres. These cytomeres were bordered by a single membrane and contained polymorphous nuclei. Merozoite differentiation was initiated at several places by protrusions appearing at the periphery of the cytomeres. The cytoplasm of the schizont merged progressively into th...
Schein E, Rehbein G, Voigt WP, Zweygarth E.The vertebrate development of Babesia equi from infected Hyalomma marginatum in Morocco was investigated in vitro and in vivo. It was demonstrated that the sporozoites of B. equi initiate a phase of exo-erythrocytic schizogony in lymphocytes both in vitro and in vivo. On the other hand, sporozoites did not invade erythrocytes in vitro. The complete vertebrate life cycle of B. equi was simulated in vitro, from the invasion of lymphocytes by sporozoites, to the development of macro- and microschizonts, the invasion of erythrocytes by merozoites, and the subsequent intra-erythrocytic schizogony. ...
Donnelly J, Joyner LP, Frank C.Racehorses imported into Kuwait were tested for serum antibodies to Babesia equi and B. caballi by complement fixation (CF) and indirect fluorescent antibody (IFA) tests. The prevalence of B. equi was high (77.1% by IFA) whereas that of B. caballi was much lower (11.4%). Data for B. equi showed that infection was acquired after about 6 months at risk and that in the following 12 months animals had antibody levels detectable by both CF and IFA tests by 24 months the CF reaction was no longer detectable. Estimates of incidence and inoculation rates were calculated and found to be consistent with...
Barban PS, Minaeva VM, Pantiukhina AN, Startseva MG.A comparative study was made of the serological properties and virus-neutralizing activity of antiencephalitis gamma-globulin and Fab-fragments isolated from it by gel-filtration. Horse immunoglobulins against the autumno-summer tick-borne encephalitis virus could be disintegrated with the aid of papaine to monovalent Fab-fragments which (according to the complement fixation reaction, the test of suppression of the complement fixation, and the HAIT) retained the serological activity whose level was compared with that of the serological activity of gamma-globulin. Fab-fragments possessed a mark...
Erbsloh JK.A short account is given of babesiosis (equine biliary fever) caused by the tick-borne protozoan Babesia equi and B. caballi, endemic in the Cape Province of South Africa. The clinical picture, diagnosis and treatment are described. In the absence of any prophylactic measures, prognosis is poor; control of the parasites in the tick-infested areas is essential.
Grigor'eva IA, Sergeevich EA, Lyskovtsev MM, Oleneva AG, Pushkarev VV.Dry erythrocytic diagnostic agents were obtained under experimental conditions for determination of antiglobulins forming in the organism of man and animals under the effect of serum preparations from the blood of horses and homologoum immunoglobulins. A study was made of the sera of 100 patients with tick-borne encephalitis treated with heterologous and homologous immunoglobulins of directed action; in response to the administration of horse gamma-globulin antiglobulins (in titres below 1 : 10000) appeared in the serum; they circulated in the blood for long periods and inhibited the accumulat...
Bast TF, Whitney E, Benach JL.In September 1970 three horses in eastern Long Island were clinically diagnosed
as having Eastern equine encephalomyelitis (EEE). At this time, EEE virus was isolated
from the blood clots of three migrating Northern Yellow-shafted Flickers, and from the brain
and liver of another Northern Yellow-shafted Flicker (Colaptes auratus lutetts). Following
this episode, a I-year arbovirus survey was conducted beginning in September 1970. Serologic
surveys indicated widespread prevalence of EEE antibodies in the avian population and also
low grade activity in various mammals. Powassan and St. Lou...
Fernandes TA, Paulino PG, Dos Santos Juliano D, Rabello CA, de Oliveira NVB, de Souza Santana M, Peckle M, Massard CL, da Costa Angelo I, Jacob JCF....Equine piroplasmosis (EP) is a reportable disease according to the World Organization for Animal Health (WOAH), caused by Babesia caballi, Theileria equi and T. haneyi. This syndrome is prevalent in tropical and subtropical regions, including various areas in Brazilian. This study examines EP in the Distrito Federal, Brazil, focusing on prevalence, epidemiological characteristics, and circulating genotypes. Epidemiological data and whole blood samples were collected from horses in the Distrito Federal. DNA was analyzed using qPCR for Theileria sp. and B. caballi, followed by cPCR for 18S rDNA ...
Sun Y, Yu YT, Castillo XO, Anderson R, Wang M, Sun Q, Tallmadge R, Sams K, Reboul G, Zehr J, Brown J, Wang X, Marra N, Stanhope B, Grenier J....Fever of unknown origin (FUO) without a respiratory component is a frequent clinical presentation in horses. Multiple pathogens, both tick-borne and enteric, can be involved as etiologic agents. An additional potential mechanism is intestinal barrier dysfunction. This case-control study aimed to detect and associate microbial taxa in blood with disease state. Areas known for a high prevalence of tick-borne diseases in humans were chosen to survey horses with FUO, which was defined as fever of 101.5°F or higher with no signs of respiratory illness or other recognisable diseases. Blood samples ...
Serpa PBS, Bogers S, Byron C, Cardona G, Patton M.A 1-year-old American Quarter horse was presented with acute onset of right hind lameness. On physical examination, there was synovial effusion of the right tarsocrural joint. Synovial fluid cytology revealed a marked eosinophilic synovitis. Serology indicated evidence of acute and chronic infection with Borrelia burgdorferi, although PCR of the synovial fluid was negative. The filly was treated with phenylbutazone and oxytetracycline, and repeated synovial cytology indicated improvement. The filly was discharged with a prescription of minocycline for 30 days. Despite initial improvement, recu...
Pinn-Woodcock TL, Aprea MS, Lejeune M, Tomlinson JE.A common diagnostic approach for febrile horses is to test for a panel of potential pathogens. Panels are curated by expert opinion and vary between diagnostic laboratories. Objective: To report the results of a newly developed equine fever diagnostic panel (EFDP) between 2019 and 2023 and evaluate the frequency of positive results. Methods: Retrospective descriptive study. Methods: The EFDP requires submission of whole blood, nasal swab, and faecal samples, and includes PCR tests for 12 pathogens that can present as fever without localising signs of illness or infection. Submission metadata a...
Pádua GT, Tavares MA, de Lima NJ, Paula WVF, Dos Santos GC, Neves LC, Bittencourt RBM, Paludo RLDR, Cardoso ERN, da Silva BBF, Pádua BR....This study sought to investigate the presence of anti- spp. antibodies in georeferenced serum samples from equids across all regions of the state of Goiás, while also presenting variables that indicate risk factors for the circulation of rickettsiae, and evaluating the presence of rickettsial DNA in ticks collected from equids and the surrounding environment in the municipalities of Uruaçu and Porangatu, located in the northern region of the state. A total of 1156 equid serum samples provided by the Goiás Agricultural Defense Agency (Agrodefesa) were analyzed for antibodies against 4 antig...
Bianchi D, Santos RRD, Peleja PL, de Sousa ABB, da Silva Evangelista M, de Almeida Júnior JS, Barata LES, Moraes WP, Minervino AHH. (tropical horse tick) is a tick species commonly found parasitizing horses and other equids in the Amazon region, causing economic losses. Currently, tick control is based on chemical acaricides, usually in a power formulation for topical use. However, its indiscriminate use results in the emergence of resistant tick lineages. Several plant compounds have been tested for their acaricide activity. In the Amazon, several plants are used for oil extraction, resulting in the production of solid residue (waste) that may contain chemical molecules with biological activities. Thus, we aimed to test ...
Crisman EC, Furr M, Ramachandran A.To determine the seroprevalence of Francisella tularensis in horses in Oklahoma and to describe factors associated with seropositivity. Unassigned: In this observational study, 238 frozen equine serum samples were tested for F tularensis by microagglutination assay (MAT). Samples were collected from 36 of 77 Oklahoma counties from 2021 through 2023. Exclusion criteria included insufficient sample quantity, cross-reactivity to Brucella abortus, and county outside of Oklahoma. The Fisher exact test was used to compare the proportion of positive tests by year, river basin, and topographic region....
Duaso J, Perez-Ecija A, Navarro A, Martínez E, De Las Heras A, Mendoza FJ.Equine piroplasmosis (EP), caused by and , is a worldwide tick-borne disease with severe economic, commercial, and sanitary implications for equids. Although diagnosis is based on direct (blood smear or PCR) or indirect (serology) methods, these techniques are expensive, laborious, and false-negative and false-positive results can be yielded. Biochemistry blood profiles are routinely performed in horses. Biochemical parameters and ratios could be a reliable complementary diagnostic tool to assist clinicians in EP diagnosis, mainly in endemic areas, or for discarding similar disorders (piro-li...
Duaso J, Perez-Ecija A, Navarro A, Martínez E, De Las Heras A, Mendoza FJ.Equine piroplasmosis (EP) is an endemic parasitic disease in southern European countries, such as Spain. Andalusia, the most southwestern region of Europe, is the community with the highest number of registered horses and farms in Spain and one of the main international exporters of Andalusian (Spanish Purebred) horses worldwide. Considering the current expansion of this disease and the possible effect of climate change on its prevalence, studying the EP prevalence in this region is compelling. Molecular (PCR) and serological methods (cELISA and IFAT) were used to study the true and apparent p...
Chatanga E, Ahedor B, Atabek B, Kainga H, Kapalamula T, Razemba T, Nakao R, Nonaka N, Sivakumar T, Yokoyama N.Equine piroplasmosis (EP) is a tick-borne disease caused by Theileria equi, Theileria haneyi, and Babesia caballi in equids, such as horses, donkeys, mules, and zebras. A comprehensive understanding of the epidemiology of T. equi and B. caballi is vital for EP management. The present study surveyed T. equi and B. caballi infections in donkeys and horses in Malawi. Blood samples were collected from 185 equines, including 178 donkeys in Lilongwe (n = 136) and Dedza (n = 42) districts, and seven horses in Lilongwe district. The blood samples were used to measure hematocrit values and prepare ...
Hacilarlioglu S, Bilgic HB, Karagenc T, Aydin HB, Toker H, Kanlioglu H, Pekagirbas M, Bakirci S.Equine piroplasmosis (EP), caused by and , is a tick-borne disease posing significant threats to equine health and the horse industry worldwide. Other vector-borne blood parasites, including , spp., and spp., can also infect horses; however, their prevalence remains poorly characterized in Türkiye. This study aimed to determine the molecular prevalence of , , , spp., and spp. in equids from the Western Aegean Region of Türkiye. Blood samples were collected from 388 clinically healthy equines across İzmir, Aydın, Denizli, and Muğla provinces. Species-specific PCR assays were performed...
Mège M, Bonsergent C, Viry L, Dhune M, Lecollinet S, Malandrin L.Equine piroplasmosis is a major tick-borne horse disease, caused by the intracellular development of piroplasms (Theileria equi sensu lato and Babesia caballi), with significant economic and sanitary consequences. In 2024, 203 blood samples were collected in Guadeloupe (Caribbean) from asymptomatic horses. Using an 18S rRNA nested PCR (nPCR) specific for each equine genus parasite, 79 samples tested positive for Theileria equi and 9 for Babesia caballi, resulting in respective prevalence of 38.9% and 4.4%. Three horses were co-infected. For B. caballi, 18S rRNA sequence analysis revealed the p...
Soliman AM, Elhawary NM, Helmy NM, El-Seify MA, Amer MM, Mohamed S, Memon FU, Rashid MHO, Gadelhaq SM.Equine piroplasmosis represents one of the main and serious health problems affecting the equines industry globally, caused by a tick-borne protozoa called and . This study aimed to identify and genotype within the equine population from Giza Governorate, Egypt, by comparing the obtained results using the available diagnostic methods. Unassigned: We collected 116 apparently healthy horses from the study area during the first half of 2019 to identify using real-time PCR (qPCR), targeting the gene. The results were compared with those from microscopic examination of Giemsa-stained blood sme...
Clark KF, Lemcke RA, Gasiorowski JC, Wagner B.Lyme arthritis, a well-documented subtype of arthritis in humans and dogs, is caused by Borrelia burgdorferi and spread primarily through ticks (Ixodes spp.). While Lyme disease in horses is known to cause a variety of clinical signs, its involvement in the development of equine arthritis is controversial. As climate change enables tick populations to expand, more horses could be exposed to B. burgdorferi; therefore, a greater understanding of how Lyme disease affects joints is critical to preserving soundness. Objective: To determine if systemic, naturally occurring Lyme disease had a discern...
Posada-Guzmán MF, Jiménez-Rocha AE, Sánchez-Bermúdez JF, Romero-Zúñiga JJ, Dolz G.Equine piroplasmosis, caused by Babesia caballi and Theileria equi, is endemic in Costa Rica. However, the presence of these hemoparasites in tick vectors has not been documented in the country. Objective: To identify tick species infesting horses in four Indigenous communities and to determine the presence of B. caballi and T. equi DNA in ticks from piroplasmosis-positive horses. Methods: Ticks (n = 1063) were collected from 129 horses in four Indigenous communities. Species identification and sex classification were performed. From 76 PCR-positive horses, 203 ticks were analyzed for B. cabal...
da Silva Rocha MB, Avelar BR, Martins Dos Santos GC, Ferreira TP, de Sousa Vieira T, de Oliveira GF, Gomes BT, Klafke GM, Correia TR, Cid YP, Scott FB.The objective of this study was to standardize a stall-trial methodology for horses in order to evaluate the pharmacokinetics and efficacy of a 1 % fipronil pour-on formulation against Dermacentor nitens. Brazilian pony breed horses were housed in individual stalls within a covered barn and artificially infested with D. nitens larvae on alternate days from day -31 to -1 before treatment. The animals were treated on day 0 with a fipronil 1 % pour-on at a dose of 1 mg/Kg body weight. To determine the therapeutic efficacy, the number of engorged females naturally detached from control and t...
Qin S, Kulabieke T, Mizhamuhan D, Zhang M, Jin M, Abula G, Pi M, Wang H, Zhang Y, Guo Q.Equine theileriosis, caused by the protozoan parasite , represents a significant economic threat to the equine industry. In Xinjiang, China, an endemic area for this disease, systematic research on the genetic diversity of has been notably lacking. The aim of this study was to obtain molecular epidemiological data pertaining to the parasite in selected regions of Xinjiang, China, and analyze the genetic characteristics (including rRNA, , and genes) and genotype distribution patterns of isolates from these regions, providing a scientific basis for developing targeted prevention and control s...
Dorrego A, Olvera-Maneu S, Jose-Cunilleras E, Gago P, Raez A, Rivera B, Oporto A, Gonzalez S, Cruz-Lopez F.The forest fly ) is an obligate haematophagous dipteran insect (order Diptera) that primarily infests horses and may contribute to the circulation of vector-borne pathogens. This study aimed to investigate the presence of , s.l., , and , important vector-borne pathogens of equids, in forest flies collected from horses in endemic areas of Spain. A total of 170 forest flies were collected from 39 equids across four geographical regions in Spain (Segovia, Madrid, Toledo, and Menorca) and blood samples were collected from 27 of these horses. All flies were morphologically and molecularly identifi...
Cardillo NN, Villarino NF, Kappmeyer LS, Chung CJ, Suarez CE, Bastos RG.Equine piroplasmosis (EP) is a tick-borne disease of equids caused by the intraerythrocytic apicomplexan parasites Theileria equi, Babesia caballi and the recently identified Theileria haneyi. Acute cases can be severe, with anemia, jaundice, abortion or sudden death. Survivors remain lifelong carriers, serving as reservoirs for tick-borne and iatrogenic transmission. No vaccines are currently available, and control strategies rely heavily on accurate diagnostics and chemotherapeutic intervention. Imidocarb dipropionate (ID) is the current standard of care for both acute treatment and radical ...
Machado RZ, André MR, Pereira JG, Oliveira MDSC, Ribeiro LSDS, Toledo CZP, Gonçalves LR.Equine Piroplasmosis (EP) is a tick-borne disease caused by the protozoan parasites Babesia caballi, Theileria equi, and Theileria haneyi, characterized by intravascular hemolysis and associated systemic illness. Although T. equi and B. caballi have been widely reported in some regions of Brazil, data from other states are limited. Additionally, despite reports of T. equi genotype C, currently recognized as T. haneyi, has been identified in Brazil, there are no investigations using T. haneyi-specific molecular tools. This study assessed the presence of these three agents in horses from Baixada...
Kwak ML, Echigo H, Hoketsu T, Taya Y, Numata H, Shiraki Y, Kelava S, Markowsky G, McInnes D, Hayashi N, Nonaka N, Kawai M, Nakao R.The control of ticks is challenging owing to their ubiquity, complex ecologies, and difficulties relating to costs and non-target impacts of chemical control programs. Nature-based solutions centre around co-opting natural processes and biodiversity to address socio-environmental problems; and in some cases, rewilded species can provide nature-based solutions. In northern Japan, the winter ecology of ticks is poorly studied, though some species are believed to overwinter under the snow. Winter grazing activity of rewilded horses may disturb overwintering ticks, exposing them to sub-zero temper...
Mota RA, Silito IS, Martins MP, Oliveira PRF, Melo RPB, Vieira da Silva V, Jorge FR, Martins TF, Labruna MB.Tick-borne diseases are among the most widespread vector-borne infections, including zoonoses caused by bacterial and protozoal microorganisms. This study consisted of a serosurvey for Rickettsia spp. in 270 horses from 11 farms in the coastal region of Pernambuco, Brazil. Through the indirect immunofluorescence assay (IFA) based on antigens of five Rickettsia species, 164 (60.7%) horses were seroreactive to Rickettsia spp., with seroreactivity among farms ranging from 10 to 100%. Through molecular analysis, all 270 horse blood DNA samples tested negative by PCR assays targeting Anaplasmatacea...
Gholmohammadi S, Malekifard F, Yakhchali M.Ticks are important ectoparasites in equids, causing economic losses in animal husbandry in Iran and worldwide. This study was aimed to determine frequency and species diversity of hard ticks in equids in Ardabil province, during the four seasons in 2021. A total of 240 equids (187 horses, 53 donkeys) were randomly selected and examined. Ixodid ticks were collected from body surface of examined animals and identified. Of all examined equids, 32.5% horses, and 4.58% donkeys were infested with a total number of 412 ixodid ticks. Tick indices (tick number per animal) were 4.62. There was signific...
Silva-Ramos CR, Niño Rodríguez JA, Gil-Mora J, Betancourt-Ruiz P, Martínez-Díaz HC, Forero-Becerra E, Matiz-González JM, Bolaños E, Olaya-M LA....Babesia species are tick-borne protozoan parasites which affect several animal species. Babesia spp. infections are significantly important for veterinary medicine, affecting a wide range of domestic animal species such as dogs, cattle, and horses. In Colombia, studies of Babesia spp. infections in domestic animals are scarce. Thus, the aim of the present study was to explore the circulation of these parasites among domestic canines, bovines and equines from the department of Cauca. Methods: Between August and November, 2017, active domestic animal sampling of cattle was performed in eight rur...
Montini M, Torrents J, Nava S, Sebastian PS. ticks collected on horses from the North-West of Argentina were analyzed for the presence of the Piroplasm agents and . A total of 97 adult ticks from four different provinces (Jujuy, Santiago del Estero, Salta, Tucumán) were included in this study. Genomic DNA was isolated, and conventional PCR assays were applied for the detection of the 18S rDNA gene of and species. One sample corresponding to a male of collected in Tapia, Tucumán Province, resulted positive. Phylogenetic analyses carried out with the obtained 18S rDNA partial gene sequences resulted in the identification of . Althou...
Kloster H, Stormo C, Haaland AH, Stuen S, Kjelland V. ticks play a crucial role as carriers of diseases, transmitting pathogens to vertebrate hosts, including horses. This study aimed to investigate the seroprevalence of IgG antibodies against sensu lato (s. l.), , and tick-borne encephalitis virus (TBE-virus) in equine sera collected in southern Norway. In total, sera from 331 horses stabled in four counties (Agder, Vestfold and Telemark, Vestland, and Viken) were analyzed by immunoblot. In total, 66% of the horses were IgG-seropositive for antibodies against one or multiple tick-borne pathogens. The highest seroprevalence was detected against...
de Albuquerque CV, da Silva Andrade M, de Freitas MS, Paulino PG, Santos HA, de Tarso Landgraf Botteon P.Equine Piroplasmosis (EP) and Equine Granulocytic Anaplasmosis (EGA) are diseases that affect horses, transmitted by ixodid ticks, causing a nonspecific febrile syndrome. Equine Piroplasmosis is endemic in Brazil, and most horses are in enzootic stability. Serological and molecular studies carried out on horses in Brazil have shown the presence of Anaplasma phagocytophilum, however, the clinical relevance of this infection has not yet been established. The present study aims to evaluate the importance of Babesia caballi, Theileria equi, and A. phagocytophilum as etiological agents in horses wi...
