首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 406 毫秒
1.
The seroprevalence and seasonal trend of antibody titers against equine monocytic ehrlichiosis (Potomac horse fever) were determined in apparently healthy horses in selected areas of Illinois in 1986. Sera from 1,367 horses (6 months to 29 years old) were evaluated for the presence of antibodies against Ehrlichia risticii with indirect immunofluorescence. The majority (88%) of the horses were Thoroughbred or Standardbred racehorses. The number of horses with antibodies against E risticii was 229/1,367 (16.75%). The titers in these horses ranged from 1:10 to 1:640. As the year progressed, the number of seropositive horses (titers greater than or equal to 1:10) and the magnitude of the titers increased significantly, both reaching a maximum in July and August, respectively (P less than 0.05). A relationship between seropositivity and gender was not detected. In the year prior to sampling, 56.8% of the seropositive horses had not been ill, whereas 0.8% had diarrhea, an episode of acute abdominal pain, or laminitis. It was concluded that a large number of horses in Illinois are exposed to E risticii, that maximal exposure occurs in July, and that the most common form of the disease in Illinois is not associated with clinical signs.  相似文献   

2.
Antibody titer to Ehrlichia risticii was determined, in 2,549 equine serum samples, using an indirect fluorescent antibody assay. During 1986, samples were obtained from the Minnesota State-Federal Equine Infectious Anemia Diagnostic Laboratory, the Minnesota Racing Laboratory, from horses admitted to the University of Minnesota Veterinary Teaching Hospital, and as a result of field investigations of horses with acute diarrhea. Results of the study revealed antibody prevalence of 33, 24, 47, and 25% for the respective groups. There was no statistical association between seropositive status and age, sex, breed, or clinical problem of horses referred to the teaching hospital. There was an increase in the total percentage of seropositive samples over the duration of the sample collection period, suggesting a seasonal exposure pattern, and E risticii was associated with clinical and subclinical infections in horses of Minnesota.  相似文献   

3.
Infection with the tapeworm Anoplocephala perfoliata has been found to be associated with equine colic in horses in the United Kingdom. Using a matched case-control study design, data collected from 117 pairs of horses in Ontario were examined for evidence of associations between risk of colic and A. perfoliata infection, and between seropositivity to infection and management practices. Cases were horses in southern Ontario diagnosed with colic by local veterinarians, and control horses were from the same stables as cases and were matched by age, breed and gender where possible. Infection status was defined on the basis of positive results upon coprological examination, and/or seropositivity to a 12/13 kDa A. perfoliata secretory protein. Fifty-six percent of the 234 horses were seropositive for A. perfoliata, but eggs were found in samples from only 6% of horses. Horses dependent on pasture for a large part of their diet were significantly more likely to have ELISA optical density levels above 0.600 compared to other horses (odds ratio [OR]=6.38; p=0.029). This finding identified exposure to pasture as an important source of A. perfoliata infection in the horses used in the study. In a subset of 46 pairs of horses for which control horses had no known history of colic, a statistically significant negative association was found between the risk of colic and optical density (OD) levels >0.200-0.600, relative to OD levels < or = 0.090 (OR=0.08; p=0.017). There was no other statistical evidence of an association between the risk of colic and A. perfoliata infection.  相似文献   

4.
Fifty-five horses were inoculated IV and/or SC with materials containing Ehrlichia risticii, ie, infected whole blood, buffy coat cells, or cell culture, to study clinical and hematologic features of equine monocytic ehrlichiosis (Potomac horse fever). Major clinical and hematologic features of induced E risticii infection were biphasic increase in rectal temperature with peak increases of 38.9 C and 39.3 C on postinoculation days (PID) 5 and 12, respectively; depression; anorexia; decreased WBC count (maximal decrease of 47% on PID 12); and diarrhea from PID 14 to PID 18. Increased WBC count was an inconsistent feature, with a maximal increase of 51.5% on PID 20. During times of decreased and increased WBC counts, lymphocyte/neutrophil ratios remained fairly constant. However, not all horses had all clinical and hematologic features, and these features were present in different degrees among horses. Increased rectal temperature, depression, anorexia, and decreased WBC count were more consistent features, whereas diarrhea developed in 73% of the horses. Of 55 horses, 39 (71%) had all clinical and hematologic features of the disease (classic disease), whereas 16 (29%) horses did not have greater than or equal to 1 of these features (nonclassic disease). The E risticii titer in the blood (ehrlichemia) was maximum during the peak increase in rectal temperature. In 55 horses, mortality was 9%. Significant differences (P greater than 0.5) in clinical and hematologic features were not detected between horses that survived and those that died of E risticii infection.  相似文献   

5.
A disease named locally as churrío or churrido equino (i.e., equine scours) has occurred for at least 100 years in Uruguay and southern Brazil in farms along both shores of the Merín lake. This report describes cases of churrido equino and provides serologic, pathologic, and DNA-based evidence indicating that the disease is in fact equine monocytic ehrlichiosis (Potomac horse fever). Results of an epidemiological investigation conducted on an endemic farm are also presented. Clinical signs in 12 horses were fever, depression, diarrhea, dehydration, and sometimes colic and distal hind limb edema. Postmortem findings of 3 horses were of acute enterocolitis. Inclusion bodies containing ehrlichial organisms were found in the cytoplasm of macrophages of the large colon of 1 horse. Eleven of the 12 horses were serologically positive to Ehrlichia risticii (indirect fluorescent antibody assay) and, of 3 paired samples, 2 showed seroconversion. Ehrlichia risticii DNA was identified by a nested polymerase chain reaction in peripheral blood of an affected horse. A healthy horse inoculated with peripheral blood from an affected horse developed the disease and antibodies to E. risticii. The disease had a peak incidence in March (summer) and was statistically associated with a marshy ecosystem near the Merín lake, where large numbers of Pomacea spp. (Ampullariidae) snails were found. Incidence density was almost 8 times higher in nonnative horses than in native horses. It was concluded that the previous diarrheic disease of horses known in Uruguay and southern Brazil as churrido equino is equine monocytic ehrlichiosis.  相似文献   

6.
REASONS FOR PERFORMING STUDY: Clostridium botulinum type C is prevalent in Israel and outbreaks recorded in many species, other than horses. Association between levels of anti-BoNT/C antibodies and equine grass sickness (EGS) have been demonstrated but seroprevalence of anti-BoNT/C antibodies in horses has not been reported nor has EGS been reported in Israel. OBJECTIVES: To determine the seroprevalence of specific anti-BoNT/C antibodies in horses in Israel and to determine whether age, breed and gender, or geographical region of farms are potential risk factors for exposure to BoNT/C. HYPOTHESIS: Anti-BoNT/C antibodies are prevalent among horses in Israel and farm and horse-level variables are associated with increased risk for exposure. METHODS: Serum samples from 198 horses were collected and the levels of specific anti-BoNT/C antibodies were determined using enzyme-linked immunosorbent assay (ELISA). For each categorical variable indicator variables were created and the odds ratio (OR) and 95% confidence intervals (95% CI) for the outcome variable were calculated using a univariable and multivariable logistic regression models. RESULTS: A total of 61 (30.8%) horses were ELISA positive for anti-BoNT/C IgG antibodies. The farm and its geographical region were associated significantly with seropositivity, horse-level variables, such as gender and breed, were also associated with seropositivity. Quarter Horse and Warmblood mares placed in the southern region of Israel had the highest odds to be tested positive for anti-BoNT/C IgG antibodies. CONCLUSIONS AND POTENTIAL RELEVANCE: Several farm and various horse-level risk factors for exposure to BoNT/C, found in this study, could be correlated to previously reported risk factors of EGS. Studies are required to determine the predisposing factors that cause EGS, which is apparently not present in Israel.  相似文献   

7.
Ehrlichia risticii, the agent of Potomac horse fever (PHF), has been recently detected in trematode stages found in snail secretions and in aquatic insects. Based on these findings, horses could conceivably be exposed to E. risticii by skin penetration with infected cercariae, by ingestion of infected cercariae in water or via metacercariae in a second intermediate host, such as an aquatic insect. In order to test this hypothesis, horses were challenged with infectious snail secretions and aquatic insects collected from a PHF endemic region in northern California. Two horses stood with their front feet in water harbouring E. risticii-infected cercariae, 2 horses drank water harbouring E. risticii-infected cercariae, and 6 horses were fed pools of different aquatic insects harbouring E. risticii-infected metacercariae. In this preliminary study, only the one horse infected orally with mature caddisflies (Dicosmoecus gilvipes) developed the clinical and haematological disease syndrome of PHF. The agent was isolated from the blood of the infected horse in a continuous cell line and identified as E. risticii by characterisation of the 16S rRNA gene. Therefore, E. risticii is maintained in nature in a complex aquatic ecosystem and transmission to horses can occur through accidental ingestion of insects such as caddisflies containing infected metacercariae. At present, the small number of horses used in this study does not exclude other insects and free trematode stages as potential sources of infection.  相似文献   

8.
The capability of field-collected American dog ticks, Dermacentor variabilis, to infect horses with Ehrlichia risticii, causative agent of Potomac horse fever (PHF), was examined by allowing adult ticks collected from horse farms with a history of PHF to feed on susceptible horses. More than 500 male and female ticks attached and fed on 3 test horses; however, no clinical or serologic evidence of PHF was observed in treated or control horses. All horses were challenge exposed with E risticii-infective blood by inoculation at 60 to 65 days after ticks fed, and all developed clinical PHF with subsequent seroconversion. The data, therefore, indicated that adult D variabilis, a common parasite of horses on Maryland premises where PHF is enzootic, may not serve as a vector of E risticii.  相似文献   

9.
A serological study of antibodies to Ehrlichia risticii was carried out on 10 species of wild and domestic mammals found on or near 21 horse farms in an area of the USA in which Potomac horse fever is endemic. No antibodies were found in 133 peridomestic rodents (Norway rats and house mice), nor in 108 wild rodents (white-footed mice and meadow voles) captured on farms. Three of the six domestic animal species examined, cats, pigs and a goat, showed serological evidence of exposure to E risticii. Seropositive animals were detected on three of the 21 premises. The eight seropositive cats (of 48 cats tested) were on two farms, and the three seropositive pigs (of 14 tested) were all on one farm which lay some 3 km from where the one seropositive goat (of three tested) was found. None of the 79 dogs, 75 cattle and seven sheep tested had antibodies to E risticii. The significance of these findings is discussed in the light of current understanding of the transmission of Potomac horse fever and of the epidemiology of other related ehrlichial diseases.  相似文献   

10.
Reasons for performing study: Crib‐biting is an equine stereotypy that may result in diseases such as colic. Certain breeds and management factors have been associated. Objectives: To determine: breed prevalence of crib‐biting in US horses; the likelihood that one horse learns to crib‐bite from another; and owner perceptions of causal factors. Methods: An initial postal survey queried the number and breed of crib‐biting horses and if a horse began after being exposed to a horse with this habit. In a follow‐up survey, a volunteer subset of owners was asked the number of affected and nonaffected horses of each breed and the extent of conspecific contact. The likelihood of crib‐biting given breed and extent of contact was quantified using odds ratio (OR) and significance of the association was assessed using the Chi‐squared test. Results: Overall prevalence was 4.4%. Thoroughbreds were the breed most affected (13.3%). Approximately half of owners believed environmental factors predominantly cause the condition (54.4%) and crib‐biting is learned by observation (48.8%). However, only 1.0% of horses became affected after being exposed to a crib‐biter. The majority (86%) of horses was turned out in the same pasture with other horses and extent of contact with conspecifics was not statistically related to risk. Conclusion: This is the first study to report breed prevalence for crib‐biting in US horses. Thoroughbreds were the breed more likely to be affected. More owners believed either environmental conditions were a predominant cause or a combination of genetic and environmental factors contributes to the behaviour. Only a small number of horses reportedly began to crib‐bite after being exposed to an affected individual, but approximately half of owners considered it to be a learned behaviour; most owners did not isolate affected horses. Potential relevance: Genetic predisposition, not just intensive management conditions and surroundings, may be a factor in the high crib‐biting prevalence in some breeds, and warrants further investigation. Little evidence exists to suggest horses learn the behaviour from other horses, and isolation may cause unnecessary stress.  相似文献   

11.
Serosurvey of horses with evidence of equine monocytic ehrlichiosis   总被引：4，自引：0，他引：4  
In August 1986, an extensive serosurvey for prevalence of IgG and IgM antibodies against Ehrlichia risticii, the causative agent of equine monocytic ehrlichiosis (EME), was performed at 2 Ohio racetracks, River Downs (RD) and Beulah Park (BP). Of 840 horses at RD and 574 at BP, 13 and 20%, respectively, were IgG antibody-positive (by indirect fluorescent antibody test results), with antibody titer ranging from 1:20 to 1:10,240. The titer observed at highest frequency at both racetracks was 1:80. A higher proportion of horses was ill at RD (operating during the summer months) than at BP (winter track). Of ill horses, 41% (24/58) at RD and 58% (11/19) at BP were seropositive. At RD, 70% (589/840) of all horses and 95% (102/107) of IgG seropositive horses had been stabled only at RD during the month prior to testing. Analysis of these sera by use of an ELISA to detect IgM antibody against E risticii antigen indicated that at RD, 42% (57/137) of the seropositive horses were IgM seropositive. At BP, 17% (20/120) of seropositive horses were IgM seropositive. The larger number of IgM seropositive horses at RD indicates that more horses were recently infected at RD than at BP (P = 0.0001). Therefore, at least half the seropositive horses at RD seemed to have acquired the infection at RD. These serosurvey data also indicate that at BP and RD, 78% (85/109) and 91% (111/122) of IgG seropositive horses, respectively, had subclinical infection. At less than or equal to 1:40 titer, there was no difference in seropositive rates between healthy and ill horses.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

12.
  相似文献   

13.
OBJECTIVE: To determine seroprevalence of FeLV and FIV infection among cats in North America and risk factors for seropositivity. DESIGN: Prospective cross-sectional survey. ANIMALS: 18,038 cats tested at 345 veterinary clinics (n=9,970) and 145 animal shelters (8,068) between August and November 2004. PROCEDURE: Cats were tested with a point-of-care ELISA for FeLV antigen and FIV antibody. A multivariable random effects logistic regression model was used to identify risk factors significantly associated with seropositivity while accounting for clinic-to-clinic (or shelter) variability. RESULTS: 409 (2.3%) cats were seropositive for FeLV antigen, and 446 (2.5%) cats were seropositive for FIV antibody; 58 (0.3%) cats were seropositive for infection with both viruses. Multivariable analysis indicated that age, sex, health status, and cat lifestyle and source were significantly associated with risk of seropositivity, with adults more likely to be seropositive than juveniles (adjusted odds ratios [ORs], 2.5 and 2.05 for FeLV and FIV seropositivity, respectively), sexually intact adult males more likely to be seropositive than sexually intact adult females (adjusted ORs, 2.4 and 4.66), and outdoor cats that were sick at the time of testing more likely to be seropositive than healthy indoor cats (adjusted ORs, 8.89 and 11.3). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that certain characteristics, such as age, sex, health status, and lifestyle, are associated with risk of FeLV and FIV seropositivity among cats in North America. However, cats in all categories were found to be at risk for infection, and current guidelines to test all cats at the time of acquisition and again during illness should be followed.  相似文献   

14.
Between Jan 1, 1984 and Aug 1, 1990, 27 horses were admitted to the veterinary medical center for evaluation of fistulous withers. Nine (37.5%) of 24 horses tested for antibody to Brucella abortus were seropositive. Horses that tested seropositive were significantly (P = 0.046) more likely to have been pastured with cattle that were seropositive for B abortus, and were significantly (P = 0.010) more likely to have had radiographic evidence of vertebral osteomyelitis than were horses that tested seronegative. Five horses that were seropositive for B abortus were administered strain 19 brucella vaccine sc (n = 1) or iv (n = 4). The horse treated by sc injection of vaccine improved during hospitalization, but was lost to follow-up evaluation. Three (75%) of 4 horses treated by iv injection died, but 1 horse recovered within 4 weeks of treatment.  相似文献   

15.
The 2007 epidemic of equine influenza in Australia provided an opportunity to investigate the effectiveness of on-farm biosecurity measures in preventing the spread of a novel pathogen in a largely naive population. We conducted a case-control study of 200 horse premises from highly affected regions of the state of New South Wales (NSW), to investigate risk factors for the spread of equine influenza onto horse premises, specifically, non-compliance with biosecurity measures recommended to horse owners by the relevant animal health authority, the NSW Department of Primary Industries. The study was restricted to cases occurring during the first seven weeks of the epidemic, a period prior to vaccination and the relaxation of some movement restrictions. Case and control premises were selected from a laboratory testing dataset and interviews were conducted with horse owners and managers on premises between July and November 2009. The proximity of premises to the nearest infected premises was the factor most strongly associated with case status. Case premises were more likely than control premises to be within 5 km and beyond 10 km of an infected premises. Having a footbath in place on the premises before any horses were infected was associated with a nearly four-fold reduction in odds of infection (odds ratio=0.27; 95% confidence interval: 0.09, 0.83). This protective association may have reflected overall premises biosecurity standards related to the fomite transmission of equine influenza. Compliance with certain on-farm biosecurity practices seemingly prevented horses on premises in high risk areas being infected with equine influenza during the 2007 outbreak in Australia. In future outbreaks, in addition to broader disease control measures, on-farm biosecurity practices should be adopted by horse owners and managers to prevent equine influenza spread.  相似文献   

16.
A study was conducted in April through August 1989 whereby 318 horses were tested for immunofluorescent antibody (IFA) titers to Ehrlichia risticii. The state of Colorado was divided into four regions and an approximately equal number of horses was tested in each region. Questionnaires were completed for each horse; a multiple logistic regression model was used to identify risk factors for horses being exposed to E. risticii.

Of the 318 horses tested, 48 (16%) had IFA titers of 1:40 or greater (range 1:40–1:1280). There was no association between the region of Colorado and seropositivity. Other variables which were not identified as risk factors included gender, transportation to other parts of Colorado, transportation to other states and exposure to other horses. When the variables were examined individually, older horses, Quarter horses, horses housed at a boarding stable, and horses having access to pasture or direct access to a stream, pond or lake were more likely to have positive titers. Horses confined to a stall with a run were less likely to be exposed to E. risticii. All apparent associations disappeared when the factors were tested in the multiple logistic regression model.  相似文献   


17.
Serological analysis of blood samples submitted to the Animal Health Trust showed that during 1995, 185 of 9203 unvaccinated horses (2.0 per cent) tested positive for antibodies to equine arteritis virus (EAV), and that during 1996, 46 of 8851 unvaccinated horses (0.52 per cent) tested positive. During both years thoroughbreds were the predominant breed tested and only a small proportion of these (<0.3 per cent), consisting predominantly of imported mares, were seropositive. In contrast, among standardbred horses, from which samples were actively solicited in 1995, 84 of 454 (18.5 per cent) were seropositive. Among standardbreds there was a difference in prevalence between types of horses, with 3.7 per cent of racing horses, 25 per cent of non-racing horses and 41 per cent of stallions testing seropositive. Investigations of seropositive stallions identified during 1994 and 1995 demonstrated that clinically inapparent equine viral arteritis (EVA) had occurred previously in the UK. Of 50 seropositive stallions, nearly half were standardbreds and nearly all had been imported from either North America or the European Union. Whether 34 seropositive stallions were shedding virus in their semen was established either by test mating, by the serology of the covered mares, or by investigation by MAFF following the introduction of the Equine Viral Arteritis Order 1995. Nine of the stallions (26.5 per cent) were identified as presumptive shedders of EAV in semen and among specific breeds, viral shedding was identified in six of 15 (40 per cent) standardbreds and three of nine (33 per cent) warmbloods. In contrast with the outbreak of EVA in the UK in 1993, no signs of disease typical of EAV infection were reported during these investigations, even in mares test mated to stallions shedding the virus.  相似文献   

18.
  相似文献   

19.
Objective To describe management practices and routine preventive care of aged horses in Queensland, Australia, including effects of owner characteristics, affiliation to an equestrian group and retirement of the horse. Methods Owners of horses were contacted via Equestrian Australia (EA) and asked to complete a questionnaire about their aged horses (e.g. age, breed, sex and colour); their use and management, including preventive health care; and use of equine healthcare providers. Results Horses aged 15 years or greater represented one-third of the total horses owned in the population sample. The median age of the horses was 20.7 years (range 15–44 years). Basic husbandry and preventive health care varied depending on demographic region, age of the horse and its use. Affiliation with EA was associated with the breed and use of the horse, but not with management or preventive health care other than frequency of hoof care visits. Retired horses had reduced basic husbandry and preventive health care compared with non-retired horses. There was reduced preventive health care in rural compared with urban areas. The majority (61%) of horses in the current study had not been visited by a veterinarian in the previous 12 months. Conclusion Aged horses constitute a large subgroup of the Australian horse population. Although basic management is at a high level for most aged horses, it appears to be reduced following the horse's retirement and in the more rural areas. There was limited veterinary involvement in preventive healthcare strategies for aged horses, especially in rural areas.  相似文献   

20.
In order to assess the level of Rhodococcus equi infection in southeast Turkey, 679 sera from healthy foals and adult horses and 78 sera from donkeys were tested by indirect ELISA using a R. equi reference strain (ATCC 33701) as antigen. Eighty (11.7%) sera from horses and 9 (11.5%) sera from donkeys with titres >0.85 were positive. The prevalence of seropositive horses in Sanliurfa Province was higher than in Diyarbakir Province; 56 (13.9%) horses in Sanliurfa Province and 24 (8.7%) horses in Diyarbakir Province were defined as seropositive. In Sanliurfa Province 14.5% of female (n=343) and 10.1% of male (n = 59) horses tested were defined as seropositive, while in Diyarbakir Province more males (11.4%, n=114) were seropositive than females (6.7%, n=163). Horses 1 to 5 years of age were found to have the highest seropositivity rate in both provinces. A total of 78 sera from donkeys were investigated in Sanliurfa Province, of which 9 (11.5%) were positive by ELISA. Among the 9 positive sera, 6 (12.8%) were from donkeys 1-5 years old and 3 (13.6%) were from donkeys >5 years of age. No positive sera were found in donkeys less than 1 year old. Five (12.5%) sera of females and 4 (10.5%) sera of males tested were positive. These results indicate the existence of R. equi in the horse populations in Sanliurfa and Diyarbakir Provinces. Similar infection rates were found for donkeys in Sanliurfa. This suggests the importance of serological surveys to diagnose R. equi infection in the region and to prevent the zoonotic risk.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号