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Topic:Ticks

Ticks are ectoparasites that can affect horses by attaching to their skin and feeding on their blood. They are vectors for various pathogens, which can lead to tick-borne diseases in horses. Common tick-borne diseases affecting equines include Lyme disease, equine piroplasmosis, and anaplasmosis. Ticks can cause irritation and skin lesions at the site of attachment, and their presence may lead to secondary infections. Management of ticks in horses involves regular inspection, use of acaricides, and environmental control measures to reduce tick populations. This page compiles peer-reviewed research studies and scholarly articles that investigate the impact of ticks on equine health, the transmission of tick-borne pathogens, and strategies for prevention and control of tick infestations in horses.
Rickettsial spotted fever in capoeirão village, Itabira, Minas Gerais, Brazil.
Revista do Instituto de Medicina Tropical de Sao Paulo    October 25, 2008   Volume 50, Issue 5 297-301 doi: 10.1590/s0036-46652008000500009
Vianna MC, Horta MC, Sangioni LA, Cortez A, Soares RM, Mafra CL, Galvão MA, Labruna MB, Gennari SM.The present study investigated the infection by spotted fever rickettsia in an endemic area for Brazilian spotted fever (BSF; caused by Rickettsia rickettsii) in Minas Gerais State, Brazil. Human, canine and equine sera samples, and Amblyomma cajennense adult ticks collected in a rural area of Itabira City, Minas Gerais State were tested for rickettsial infection. Through Immunofluorescence Assay (IFA) we demonstrated the presence of antibodies anti-R. rickettsii in 8.2%, 81.3% and 100% of the human, canine and equine sera, respectively. None of the 356 tick specimens analyzed were positive fo...
Anaplasma phagocytophilum in horses and ticks: a preliminary survey of Central Italy.
Comparative immunology, microbiology and infectious diseases    September 20, 2008   Volume 33, Issue 1 73-83 doi: 10.1016/j.cimid.2008.08.002
Passamonti F, Veronesi F, Cappelli K, Capomaccio S, Coppola G, Marenzoni ML, Piergili FD, Verini SA, Coletti M.Anaplasma phagocytophilum, the causative agent of granulocytic ehrlichiosis, affects several species of wild and domesticated mammals, including horses. In this work we compared direct and indirect methods to evaluate A. phagocytophilum presence in Central Italy: 135 sera were screened by IFA for A. phagocytophilum and other haemopathogens (Theileria equi and Babesia caballi). Each horse was also tested for A. phagocytophilum 16S rRNA with a nested-PCR technique. In order to examine the risk of A. phagocytophilum transmission, 114 ticks were examined for the presence of A. phagocytophilum by P...
[Control of Anocentor nitens (Neumann, 1897) (Acari: Ixodidae) on equines]. Bello AC, Da Cunha AP, Leite RC, Oliveira PR, Ribeiro AC, Domingues LN, De Freitas CM, Bastianetto E, Dalla Rosa RC.This trial evaluated control practices of Anocentor nitens on equines, using spraying devices and application of acaricide paste formulation in the auricular pavilion and nasal diverticulum. The study was carried out from October 2003 to March of 2008 and the evaluations had been divided in the following stages: Phase 1--out/03 mar/04 and Phases 2, 3, 4 and 5, respectively, correspondents to the month's periods until março/08. It was used score of 0 to 3 to classify infestation levels. From abr/04 to mar/06 was implanted a schedule of acaricide sprayings every seven days and divided in two se...
[Horse Advisory Committee III–infectious complications–tick infestation].
Tijdschrift voor diergeneeskunde    June 27, 2008   Volume 133, Issue 11 478-480 
Werners-Butler CM, Daha TJ, van Door DC, van Duijkeren E, Goehring LS, Houwers DJ, Laan TT, van Maanen C, Picavet T....No abstract available
Persistently infected horses are reservoirs for intrastadial tick-borne transmission of the apicomplexan parasite Babesia equi.
Infection and immunity    May 19, 2008   Volume 76, Issue 8 3525-3529 doi: 10.1128/IAI.00251-08
Ueti MW, Palmer GH, Scoles GA, Kappmeyer LS, Knowles DP.Tick-borne pathogens may be transmitted intrastadially and transstadially within a single vector generation as well as vertically between generations. Understanding the mode and relative efficiency of this transmission is required for infection control. In this study, we established that adult male Rhipicephalus microplus ticks efficiently acquire the protozoal pathogen Babesia equi during acute and persistent infections and transmit it intrastadially to naïve horses. Although the level of parasitemia during acquisition feeding affected the efficiency of the initial tick infection, infected t...
Validation of an in-clinic enzyme-linked immunosorbent assay kit for diagnosis of Borrelia burgdorferi infection in horses. Johnson AL, Divers TJ, Chang YF.Confirmation of Borrelia burgdorferi infection in horses has required enzyme-linked immunosorbent assay (ELISA) or Western blot tests performed by reference laboratories. An in-clinic C6 ELISA SNAP kit has been marketed for dogs. This canine kit was evaluated for horses using serum from experimentally infected ponies. Serum samples originated from 2 previous studies. In the first study, 7 ponies were exposed to B. burgdorferi-infected ticks; 4 ponies served as uninfected controls. Serum samples were obtained bimonthly for 9 months. In the second study, 16 ponies were exposed to B. burgdorferi-...
[Strategic control of Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae) on horses, Minas Gerais, Brazil – Part I]. Cunha AP, Bello AC, Leite RC, Bastianetto E, Ribeiro AC, Freitas CM, Oliveira PR.The aim of this study was to verify the efficiency of a strategic control program of Amblyomma cajennense in horses under field conditions. Acaricide treatments were applied at seven days intervals and divided in two series, the first one beginning in April 2004 (eight treatments), and the second one beginning in July 2004 (five treatments), aiming to control larvae and nymphs of the tick. A pyrethroid chemical base cypermethrin 0.015% was used for spraying the horses. There was a reduction of 44.85% in the adults infestation of the tick in the period of October 2004 to March 2005, and 59.74%,...
Rickettsia infection in five areas of the state of São Paulo, Brazil.
Memorias do Instituto Oswaldo Cruz    December 21, 2007   Volume 102, Issue 7 793-801 doi: 10.1590/s0074-02762007000700003
Horta MC, Labruna MB, Pinter A, Linardi PM, Schumaker TT.This study investigated rickettsial infection in animals, humans, ticks, and fleas collected in five areas of the state of São Paulo. Eight flea species (Adoratopsylla antiquorum antiquorum, Ctenocephalides felis felis, Polygenis atopus, Polygenis rimatus, Polygenis roberti roberti, Polygenis tripus, Rhopalopsyllus lugubris, and Rhopalopsyllus lutzi lutzi), and five tick species (Amblyomma aureolatum, Amblyomma cajennense, Amblyomma dubitatum, Ixodes loricatus, and Rhipicephalus sanguineus) were collected from dogs, cats, and opossums. Rickettsia felis was the only rickettsia found infecting ...
Efficacy of 2,6-dichlorophenol lure to control Dermacentor nitens.
Veterinary parasitology    April 24, 2007   Volume 147, Issue 1-2 155-160 doi: 10.1016/j.vetpar.2007.02.037
Borges LM, Ferreira LA, da Silva LS, de Oliveira RA, Mussi SV, Faria KA, Melo LS, Abud LJ, Costa GL, Soares SF.This study was carried out with the objective of evaluating the efficacy of a 2,6-dichlorophenol (2,6-DCP) lure to control Dermacentor nitens (Acari: Ixodidae). Slow-release formulations of the pheromone formulated with and without cypermethrin were prepared. Olfactometer bioassays were used to define the best dose of the pheromone and to evaluate the effect of cypermethrin with 2,6-DCP attractiveness. Sexually active males were released 15 cm from 2 cmx1 cm pieces of polypropylene treated with different odors: 2,6-DCP in a liposphere system (1.5, 30 and 300 microg--without cypermethrin and 30...
Age-dependent dynamics of Theileria equi and Babesia caballi infections in southwest Mongolia based on IFAT and/or PCR prevalence data from domestic horses and ticks.
Parasitology    February 19, 2007   Volume 134, Issue Pt 7 939-947 doi: 10.1017/S0031182007002405
Rüegg SR, Torgerson P, Deplazes P, Mathis A.Epidemiological factors of tick-borne equine piroplasmoses, caused by Theileria equi and Babesia caballi, were investigated using logistic regression (GLM) and general additive models (GAM) based on the prevalences determined in 510 domestic horses and in ticks in S.W. Mongolia by indirect immunofluorescence antibody test (IFAT) and/or multiplex PCR. Prevalences of T. equi and B. caballi in horses were 66.5% (95% CI: 62.1-70.7) and 19.1% (15.6-22.9), respectively by PCR and 78.8% (74.9-82.3) and 65.7% (61.3-69.9) by IFAT. Of 166 ticks analysed from PCR- and IFAT-negative horses 1 was PCR posit...
New findings on anaplasmosis caused by infection with Anaplasma phagocytophilum.
Annals of the New York Academy of Sciences    December 1, 2006   Volume 1081 360-370 doi: 10.1196/annals.1373.053
Lillini E, Macrì G, Proietti G, Scarpulla M.Ixodes ricinus (I. ricinus) is one of the vectors of Anaplasma phagocytophilum (A. phagocytophilum) in Europe, in which rates of infection range from 1.9% to 34%. In 1998, human granulocytic ehrlichiosis-like (HGE-like) Ehrlichia DNA was detected in Italy, by PCR technique in one I. ricinus nymph out of 55 ticks that were examined. In 1996, 6.3% of 310 human sera in high-risk subjects from Italy were found positive for antibodies to Ehrlichia phagocytophila (E. phagocytophila). In the same year, the authors reported the first case of equine granulocytic ehrlichiosis. In 1997, only 2 out of 563...
Fecal NIRS: detection of tick infestations in cattle and horses.
Veterinary parasitology    November 13, 2006   Volume 144, Issue 1-2 146-152 doi: 10.1016/j.vetpar.2006.09.018
Tolleson DR, Teel PD, Stuth JW, Strey OF, Welsh TH, Carstens GE.Anti-tick treatments are often applied concurrent to routine livestock management practices with little regard to actual infestation levels. Prescription treatments against ticks on grazing cattle would be facilitated by non-invasive detection methods. One such method is fecal near infrared spectroscopy (NIRS). Four studies utilizing cattle (Bos spp.) and one with horses (Equus caballus) fed varying diets and infested with either Amblyomma americanum, A. maculatum, A. cajennense or Dermacentor albipictus were conducted to determine the ability of fecal NIRS to identify samples from animals wit...
Distribution and characterization of Borrelia burgdorferi isolates from Ixodes scapularis and presence in mammalian hosts in Ontario, Canada.
Journal of medical entomology    August 9, 2006   Volume 43, Issue 4 762-773 doi: 10.1603/0022-2585(2006)43[762:DACOBB]2.0.CO;2
Morshed MG, Scott JD, Fernando K, Geddes G, McNabb A, Mak S, Durden LA.The blacklegged tick, Ixodes scapularis Say (Acari: Ixodidae), has a wide geographical distribution in Ontario, Canada, with a detected range extending at least as far north as the 50th parallel. Our data of 591 adult I. scapularis submissions collected from domestic animals (canines, felines, and equines) and humans during a 10-yr period (1993-2002) discloses a monthly questing activity in Ontario that peaks in May and October. The Lyme disease spirochete Borrelia burgdorferi Johnson, Schmidt, Hyde, Steigerwalt & Brenner was detected in 12.9% of I. scapularis adults collected from domesti...
[An epidemiological survey of equine anaplasmosis (Anaplasma phagocytophilum) in southern France].
Revue scientifique et technique (International Office of Epizootics)    April 29, 2006   Volume 24, Issue 3 899-908 
Leblond A, Pradier S, Pitel PH, Fortier G, Boireau P, Chadoeuf J, Sabatier P.Anaplasmosis is caused by the bacterium Anaplasma phagocytophilum and transmitted by Ixodes spp. ticks. According to some reports the disease can be introduced into disease-free zones by migrating birds. The purpose of this study was to evaluate the seroprevalence of A. phagocytophilum in horses in the Camargue. Data concerning 424 horses were gathered and the sera were tested for A. phagocytophilum and for piroplasmoses using an enzyme-linked immunosorbent assay and a complement fixation test, respectively. The seroprevalence rates were 11.3 % for A. phagocytophilum, 64.4 % for Theileria equi...
Seroprevalence of Anaplasma phagocytophilum among healthy dogs and horses in Israel.
Journal of veterinary medicine. B, Infectious diseases and veterinary public health    April 22, 2006   Volume 53, Issue 2 78-80 doi: 10.1111/j.1439-0450.2006.00911.x
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 ...
[Characterization of Rickettsia spp. circulating in a silent peri-urban focus for Brazilian spotted fever in Caratinga, Minas Gerais, Brazil].
Cadernos de saude publica    March 27, 2006   Volume 22, Issue 3 495-501 doi: 10.1590/s0102-311x2006000300004
Cardoso LD, Freitas RN, Mafra CL, Neves CV, Figueira FC, Labruna MB, Gennari SM, Walker DH, Galvão MA.The present study was intended to characterize Rickettsia spp. circulating in arthropod vectors in Caratinga, Minas Gerais, Brazil, by PCR and to investigate the presence of antibodies against the spotted fever Rickettsiae group (SFRG) in dogs and horses. 2,610 arthropods were collected and taxonomically identified. DNA samples obtained from these vectors were submitted to PCR and cycle-sequenced. Ctenocephalides and Amblyomma cajennense showed sequences presenting 100.0% homology with R. felis. A sequence obtained from Rhipicephalus sanguineus showed 99.0% homology with R. felis, and a sequen...
Survey on the subject of equine Lyme borreliosis.
International journal of medical microbiology : IJMM    March 9, 2006   Volume 296 Suppl 40 274-279 doi: 10.1016/j.ijmm.2006.01.004
Gall Y, Pfister K.According to the results of a questionnaire on equine Lyme borreliosis addressing veterinarians in Germany, the existence of the disease was confirmed by more than half of the 118 participants. Practitioners who regarded Borrelia burgdorferi as a pathogen of horses seemed to be more sensitized in terms of the number of annually diagnosed cases as well as the frequency of occurrence of tick infestation with equine patients or prophylactic treatments against ectoparasites by horse owners. Chronically poor performance and diverse orthopaedic problems were the clinical symptoms most often leading ...
Rhythm of engorgement and detachment of Anocentor nitens females feeding on horses.
Veterinary parasitology    February 14, 2006   Volume 137, Issue 3-4 316-332 doi: 10.1016/j.vetpar.2006.01.025
Labruna MB, Amaku M.The present study evaluated the engorgement and drop-off rhythms of Anocentor nitens females feeding on horses. Drop-off rhythm was evaluated at 6h-intervals (06:00, 12:00, 18:00, and 00:00 h) on horses held in stalls or in a pasture. A new method of marking feeding female ticks (the bowknot technique) was developed to evaluate ticks on horses in pasture that attached to different parts of the horse's body. This technique was highly successful, indicating no significant interference on tick engorgement rate or final tick weight, length and reproductive capability. Horses held in the pasture du...
Borrelia burgdorferi infections with special reference to horses. A review.
The veterinary quarterly    January 13, 2006   Volume 27, Issue 4 146-156 
Butler CM, Houwers DJ, Jongejan F, van der Kolk JH.This review discusses the literature on B. burgdorferi infections in view of the rising incidence of this infection in general and the increasing concerns of horse owners and equine practitioners. Lyme disease, the clinical expression of Borrelia infections in man is an important health problem. The geographic distribution of B. burgdorferi infections in equidae should resemble that of human cases because the vector tick involved, Ixodes ricinus, feeds on both species and, indeed, the infection has been established many times in horses. However, a definite diagnosis of the disease "Lyme borrel...
Ability of the vector tick Boophilus microplus to acquire and transmit Babesia equi following feeding on chronically infected horses with low-level parasitemia.
Journal of clinical microbiology    August 6, 2005   Volume 43, Issue 8 3755-3759 doi: 10.1128/JCM.43.8.3755-3759.2005
Ueti MW, Palmer GH, Kappmeyer LS, Statdfield M, Scoles GA, Knowles DP.The protozoan parasite Babesia equi replicates within erythrocytes. During the acute phase of infection, B. equi can reach high levels of parasitemia, resulting in a hemolytic crisis. Horses that recover from the acute phase of the disease remain chronically infected. Subsequent transmission is dependent upon the ability of vector ticks to acquire B. equi and, following development and replication, establishment of B. equi in the salivary glands. Although restriction of the movement of chronically infected horses with B. equi is based on the presumption that ticks can acquire and transmit the ...
Serologic and molecular characterization of Anaplasma species infection in farm animals and ticks from Sicily.
Veterinary parasitology    July 27, 2005   Volume 133, Issue 4 357-362 doi: 10.1016/j.vetpar.2005.05.063
de la Fuente J, Torina A, Caracappa S, Tumino G, Furlá R, Almazán C, Kocan KM.Although Anaplasma marginale was known to be endemic in Italy, the diversity of Anaplasma spp. from this area have not been characterized. In this study, the prevalence of Anaplasma spp. antibodies in randomly selected farm animals collected on the island of Sicily was determined by use of a MSP5 cELISA for Anaplasma spp. and an immunofluorescence test specific for Anaplasma phagocytophilum. Genetic variation among strains of Anaplasma spp. from animals and ticks was characterized using the A. marginale msp1alpha and the Anaplasma spp. msp4 genes. Eight species of ticks were collected and test...
Ticks and tick-borne disease in Guatemalan cattle and horses.
Veterinary parasitology    June 7, 2005   Volume 131, Issue 1-2 119-127 doi: 10.1016/j.vetpar.2005.04.033
Teglas M, Matern E, Lein S, Foley P, Mahan SM, Foley J.Blood samples and ticks were collected from 48 cattle and 74 horses from seven sites in the Peten region of Guatemala. Data on body condition, mucous membrane capillary refill time and tick infestation levels were recorded for each animal in the study. Horses had significantly higher levels of tick infestation than cattle, as well as poorer body condition scores. Seroprevalence of Babesia spp. was 95.8% for B. bovis in cattle, 89.6% for B. bigemina in cattle, and 92.7% for B. equi in horses. Seroprevalence of Anaplasma marginale in cattle was 87.5%, similar to reports in animals from other reg...
Antibiotic treatment of experimentally Borrelia burgdorferi-infected ponies.
Veterinary microbiology    May 3, 2005   Volume 107, Issue 3-4 285-294 doi: 10.1016/j.vetmic.2005.02.006
Chang YF, Ku YW, Chang CF, Chang CD, McDonough SP, Divers T, Pough M, Torres A.The objective of this study is to determine whether doxycycline, ceftiofur or tetracycline could be effectively used to treat equine Lyme disease. Ponies experimentally infected with Borrelia burgdorferi by tick exposure were treated with doxycycline, ceftiofur or tetracycline for 4 weeks (28 days). Doxycyline and ceftiofur treatment were inconsistent in eliminating persistent infection in this experimental model. However, tetracycline treatment seems to eliminate persistent infection. Although serum antibody levels to B. burgdorferi in all ponies declined gradually after antibiotic treatment,...
Rickettsial infection in animals and Brazilian spotted fever endemicity.
Emerging infectious diseases    March 9, 2005   Volume 11, Issue 2 265-270 doi: 10.3201/eid1102.040656
Sangioni LA, Horta MC, Vianna MC, Gennari SM, Soares RM, Galvão MA, Schumaker TT, Ferreira F, Vidotto O, Labruna MB.We compared the rickettsial infection status of Amblyomma cajennense ticks, humans, dogs, and horses in both Brazilian spotted fever (BSF)-endemic and -nonendemic areas in the state of Sao Paulo, Brazil. Most of the horses and few dogs from BSF-endemic areas had serologic titers against Rickettsia rickettsii antigens. In contrast, no dogs or horses from BSF-nonendemic areas had serologic titers against R. rickettsii antigens, although they were continually exposed to A. cajennense ticks. All human serum samples and ticks from both areas were negative by serologic assay and polymerase chain rea...
Successful infestation by Amblyomma pseudoconcolor and A. cooperi (Acari: Ixodidae) on horses.
Annals of the New York Academy of Sciences    December 18, 2004   Volume 1026 232-234 doi: 10.1196/annals.1307.035
Chacon SC, Faccini JL, Bittencourt VR.The host relationships for most species of the genus Amblyomma are poorly known in Brazil. The ability of A. pseudoconcolor and A. cooperi to successfully feed on horses was investigated during ongoing research on the life cycle of these two species, which are primarily associated with wildlife. Results of these experiments suggest that horses are potential hosts for the adult stages of both species.
A cross-sectional study of epizootic lymphangitis in cart-mules in western Ethiopia.
Preventive veterinary medicine    December 8, 2004   Volume 66, Issue 1-4 93-99 doi: 10.1016/j.prevetmed.2004.09.008
Ameni G, Terefe W.A cross-sectional study was conducted to determine the prevalence of epizootic lymphangitis (EL) in 309 cart-mules (cart-pulling mules) in Bako and Ejaji towns, Western Ethiopia using clinical and microbiological examinations, between November 2002 and April 2003. The overall prevalence was 21% (CI=16.6-26%). The clinical, histological and mycological characteristics of EL in a cart-mule were similar with those in a horse. There was significant (chi2=133.5, P=0.001) association between tick infestation and EL lesions in study cart-mules. Amblyoma coherence and Boophilus genera were the ticks c...
Rapid sequential changeover of expressed p44 genes during the acute phase of Anaplasma phagocytophilum infection in horses.
Infection and immunity    November 24, 2004   Volume 72, Issue 12 6852-6859 doi: 10.1128/IAI.72.12.6852-6859.2004
Wang X, Rikihisa Y, Lai TH, Kumagai Y, Zhi N, Reed SM.Anaplasma phagocytophilum immunodominant polymorphic major surface protein P44s have been hypothesized to go through antigenic variation, but the within-host dynamics of p44 expression has not been demonstrated. In the present study we investigated the composition and changes of p44 transcripts in the blood during the acute phase of well-defined laboratory A. phagocytophilum infections in naive equine hosts. Three traveling waves of sequential population changeovers of the p44 transcript species were observed within a single peak of rickettsemia of less than 1 month. During the logarithmic inc...
Amblyomma cajennense ticks induce immediate hypersensitivity in horses and donkeys.
Experimental & applied acarology    August 3, 2004   Volume 33, Issue 1-2 109-117 doi: 10.1023/b:appa.0000030016.33747.99
Szabó MP, Castagnolli KC, Santana DA, de Castro MB, Romano MA.Since host immune reaction to ticks interferes with tick-borne pathogen transmission, it is important to recognize naturally occurring tick-host immune relationships to better understand the epidemiology of such infectious diseases. Amblyomma cajennense is an important tick-borne disease vector in the Neotropical region and horses maintain it in domestic environments. In the present work intradermal testing of A. cajennense tick exposed horses and donkeys using crude tick antigens was used to evaluate the type of hypersensitivity induced by infestations. Animals sensitized by A. cajennense inf...
Detection and identification of equine Theileria and Babesia species by reverse line blotting: epidemiological survey and phylogenetic analysis.
Veterinary parasitology    July 22, 2004   Volume 123, Issue 1-2 41-54 doi: 10.1016/j.vetpar.2004.04.010
Nagore D, García-Sanmartín J, García-Pérez AL, Juste RA, Hurtado A.Specific oligonucleotide probes were designed to develop a new and highly sensitive reverse line blot assay to detect and identify simultaneously different Theileria and Babesia species in horses. The amplified hypervariable V4 region of the 18S rRNA gene was hybridised against different generic and species-specific probes. The survey was conducted over 243 samples of equine blood divided into three different groups: group 1, 24 horses presented as possible clinical piroplasmosis; group 2, 181 clinically healthy free-ranging horses exposed to ticks; group 3, 38 riding horses with unrelated pat...
Prevalence of antibodies to spotted fever group rickettsiae in humans and domestic animals in a Brazilian spotted fever-endemic area in the state of São Paulo, Brazil: serologic evidence for infection by Rickettsia rickettsii and another spotted fever group Rickettsia.
The American journal of tropical medicine and hygiene    July 9, 2004   Volume 71, Issue 1 93-97 
Horta MC, Labruna MB, Sangioni LA, Vianna MC, Gennari SM, Galvão MA, Mafra CL, Vidotto O, Schumaker TT, Walker DH.In serum samples obtained from all the healthy humans, horses, dogs, and donkeys present on three farms in the Pedreira Municipality, an endemic area for Brazilian spotted fever, an indirect immunofluorescence assay (IFA) detected antibodies against Rickettsia rickettsii in 17 (77.3%) horses, 5 (31.3%) dogs (titers ranging from 64 to 4,048), and none of 4 donkeys or 50 humans. Five canine and eight equine sera with high antibody titers to R. rickettsii were also tested by IFA against R. bellii, R. akari, and R. africae antigens. Sera from two horses and two dogs that showed similar high antibo...