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1.
Rickettsia felis is associated with fever, headache, myalgia, and macular rash in some infected humans and has been detected in the cat flea (Ctenocephalides felis) in many countries around the world. While some naturally exposed cats have been assessed for antibodies against R felis, to our knowledge, no one has reported use of polymerase chain reaction (PCR) to attempt to amplify R felis DNA from client-owned cats and the fleas collected from them. In this study, we assayed 92 pairs of cat blood and flea extracts from Alabama, Maryland and Texas, using PCR assays that amplify a region of the citrate synthase gene (gltA) and the outer membrane protein B gene (ompB). Of the 92 pairs, 62 of 92 (67.4%) flea extracts and none of the cat blood samples were positive for R felis DNA.  相似文献   

2.
Female Beagles were inoculated intradermally with a sublethal dose of Rickettsia rickettsii and R montana. Three dogs (group 1) were inoculated with 2 X 10(2) plaque-forming units (PFU) of R rickettsia and were treated with tetracycline beginning on postinoculation day (PID) 12; 3 dogs (group 2) were inoculated with 2 X 10(2) PFU of R rickettsii but were not treated; 3 dogs (group 3) were inoculated with 2 X 10(2) PFU of R montana. Group-3 dogs failed to seroconvert and were inoculated a second time on PID 68. Groups 1 and 2 dogs inoculated with R rickettsii became depressed and developed occasional inappetence, fever, hematochezia, and ocular lesions. These dogs had a decrease in PCV and RBC count, an initial decrease in WBC count followed by leukocytosis, and a decrease in platelet count. Group-3 dogs inoculated with R montana remained healthy. After R rickettsii inoculation, the serologic response to spotted fever group (SFG) rickettsial antigens (R rickettsii, R rhipicephali, R montana, and R bellii) was similar. The antibody response to R rickettsii was first detected on PID 9, with peak titers reached by PID 20. Serum titers to R rickettsii remained stable or decreased one dilution through PID 120. Of 4 SFG rickettsial antigens, the highest serologic response was to R rickettsii. A cross-reacting antibody response with R rhipicephali and R montana was nearly identical and was only slightly less than the response to R rickettsii. Cross-reacting antibodies to R belli were of lower mean titer and of shorter duration than were cross-reacting antibodies to other SFG rickettsiae.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

3.
A survey for the prevalence of Rocky Mountain spotted fever antibodies in dogs from a well-defined endemic area in Columbus, Ohio (Franklin County), was conducted during the summer of 1981. Seventy-three blood samples from dogs in this area were tested by microimmunofluorescence for antibodies to Rickettsia rickettsii and other rickettsial antigens. Thirty-three (45.2%) of these samples were positive for R rickettsii, with titers ranging from 1:8 to 1:2,048. For comparison, 137 blood samples from dogs at the Franklin County Dog Pound also were tested. One dog (0.7%) from the comparison group was seropositive to R rickettsii, with a 1:64 titer. The results indicated a nidus of this disease within the city of Columbus, Ohio.  相似文献   

4.
Flea infestations are common in Thailand, but little is known about the flea-borne infections. Fifty flea pools and 153 blood samples were collected from client-owned cats between June and August 2009 from veterinary hospitals in Bangkok, Thailand. Total DNA was extracted from all samples, and then assessed by conventional PCR assays. The prevalence rates of Bartonella spp. in blood and flea samples were 17% and 32%, respectively, with DNA of Bartonella henselae and Bartonella clarridgeiae being amplified most commonly. Bartonella koehlerae DNA was amplified for the first time in Thailand. Hemoplasma DNA was amplified from 23% and 34% of blood samples and flea pools, respectively, with 'Candidatus Mycoplasma haemominutum' and Mycoplasma haemofelis being detected most frequently. All samples were negative for Rickettsia felis. Prevalence rate of B. henselae DNA was increased 6.9 times in cats with flea infestation. Cats administered flea control products were 4.2 times less likely to be Bartonella-infected.  相似文献   

5.
Spotted fever is a disease caused by bacteria from the genus Rickettsia of the spotted fever group (SFG). Rickettsia rickettsii is likely the main agent of Brazilian spotted fever (BSF). With the objective of gathering information on the circulation of SFG rickettsiae in Londrina, Parana state, ticks from dogs and horses and also blood from dogs, horses and humans were collected in a neighbourhood of the city which presented potential for circulation of rickettsiae between hosts and vectors. Amblyomma cajennense, Dermacentor nitens, and Rhipicephalus sanguineus ticks were subjected to Polymerase Chain Reaction targeting a fragment of the Rickettsia gltA gene. This specific gene encodes the enzyme citrate synthase of Rickettsia spp., and results on all ticks were negative. Human and animal sera were tested by Indirect Immunofluorescence Assay in which R. rickettsii and R. parkeri were used as antigens. Sera from 4.7% human, 2.7% canine and 38.5% equine were positive for R. rickettsii. For R. parkeri, 0.9% human, 2.7% canine and 11.5% equine samples were positive. All samples reactive to R. parkeri also reacted to R. rickettsii. An epidemiological questionnaire was applied, but there were no statistically significant results. Comparison of our serological results with previous studies in Brazil, among BSF endemic and non-endemic areas, indicates that there is no established rickettsial infection in the study area, a statement corroborated with our molecular analysis. Nonetheless, as humans of the present study are highly exposed to tick infestations, health education within the population is needed to obtain efficient tick control.  相似文献   

6.
The objective of this study was to determine the prevalence rates for select infectious agents of cats presented to the Royal (Dick) School of Veterinary Studies at the University of Edinburgh, Scotland. Whole blood, serum, and oral mucosal and nail bed swabs were collected. While Ehrlichia species, Anaplasma species or Rickettsia felis DNA were not amplified from any cat, 44.2% of the cats had evidence of infection or exposure to either a Bartonella species (15.3% were seropositive and 5.8% polymerase chain reaction (PCR) positive), a haemoplasma (28.6% PCR positive), and/or Toxoplasma gondii (19.2% seropositive). No Bartonella species DNA was amplified from the nail or oral mucosal swabs despite a 5.8% amplification rate from the blood samples. This finding likely reflects the absence of Ctenocephalides felis infection from our study population, as this organism is a key component for Bartonella species translocation in cats. The results from this study support the use of flea control products to lessen exposure of cats (and people) to Bartonella species and support discouraging the feeding of raw meat to cats and preventing them from hunting to lessen T gondii infection.  相似文献   

7.
Objectives To define the prevalence of Bartonella spp., Rickettsia felis, Mycoplasma haemofelis, ‘Candidatus Mycoplasma haemominutum’ (Mhm) and ‘Candidatus Mycoplasma turicensis’ (Mtc) in cats and their fleas in eastern Australia. Design and procedure Conventional PCR assays that detect Bartonella spp., M. haemofelis, Mhm, Mtc, Rickettsia spp., Ehrlichia spp., Anaplasma spp. and Neorickettsia spp. were performed on DNA extracted from blood and fleas collected from 111 cats. Cat sera were assayed by ELISA for IgG of Bartonella spp. Results DNA of M. haemofelis, Mtc and Mhm was amplified from 1 (0.9%), 1 (0.9%) and 17 cats (15.3%), respectively. Only DNA of Mhm was amplified from the 62 of 111 pooled flea samples (flea sets; 55.9%). Overall, the prevalence rates for Bartonella spp. DNA in the cats and the flea sets was 16.2% (18 cats) and 28.8% (32 flea sets), respectively. Bartonella spp. IgG was detected in 42 cats (37.8%), of which 11 (26.2%) were positive for Bartonella spp. DNA in their blood. R. felis DNA was amplified from 22 flea sets (19.8%), but not from cats. Overall, DNA of one or more of the organisms was amplified from 27% (30) of cats and 67.6% (75) of the flea sets. Conclusions This is the first Australian study to determine the prevalence of R. felis and B. clarridgeiae in both fleas and the cats from which they were collected. Flea-associated infectious agents are common in cats and fleas in eastern Australia and support the recommendation that stringent flea control be maintained on cats.  相似文献   

8.
The carriage of Bartonella, Rickettsia felis and haemoplasma species was investigated in cat fleas (Ctenocephalides felis) collected from 121 cats and dogs in the United Kingdom. DNA extracted from fleas was analysed using genus and species-specific PCR and amplicons were characterised using DNA sequencing. Fifty percent of flea samples were PCR positive for at least one pathogen. Twenty one percent were positive for R. felis, 17% for Bartonella henselae, 40% for haemoplasma species and 20% were infected with more than one of the pathogen species studied. It is clear from the results in this study that companion cats and dogs are commonly infested with Ct. felis carrying bacterial pathogens of significance to human and animal health. These findings raise the possibility that Ct. felis found on dogs and cats are a potential source of infection with such pathogens for humans.  相似文献   

9.
Rickettsioses and bartonelloses are arthropod-borne diseases of mammals with widespread geographical distributions. Yet their occurrence in specific regions, their association with different vectors and hosts and the infection rate of arthropod-vectors with these agents remain poorly studied in South-east Asia. We conducted entomological field surveys in the Lao PDR (Laos) and Borneo, Malaysia by surveying fleas, ticks, and lice from domestic dogs and collected additional samples from domestic cows and pigs in Laos. Rickettsia felis was detected by real-time PCR with similar overall flea infection rate in Laos (76.6%, 69/90) and Borneo (74.4%, 268/360). Both of the encountered flea vectors Ctenocephalides orientis and Ctenocephalides felis felis were infected with R. felis. The degrees of similarity of partial gltA and ompA genes with recognized species indicate the rickettsia detected in two Boophilus spp. ticks collected from a cow in Laos may be a new species. Isolation and further characterization will be necessary to specify it as a new species. Bartonella clarridgeiae was detected in 3/90 (3.3%) and 2/360 (0.6%) of examined fleas from Laos and Borneo, respectively. Two fleas collected in Laos and one flea collected in Borneo were co-infected with both R. felis and B. clarridgeiae. Further investigations are needed in order to isolate these agents and to determine their epidemiology and aetiological role in unknown fever in patients from these areas.  相似文献   

10.
Antibodies to spotted fever-group rickettsiae in dogs in North Carolina   总被引：1，自引：0，他引：1  
A seroepidemiologic survey was conducted to determine the prevalence of antibodies reactive with 4 spotted fever-group (SFG) rickettsiae in sera of dogs from various geographic regions in North Carolina. Serum specimens were obtained from 600 dogs, and antibody titers were determined, using microimmunofluorescence. Data analysis (setting as the criterion for a positive result, a Rickettsia rickettsii titer greater than or equal to 1:64) overestimated the actual prevalence of canine exposure to this rickettsia. When data were analyzed by considering each dog's serologic response to all 4 rickettsial antigens simultaneously, the prevalence rate for exposure to R montana was 15%, to R rhipicephali was 11%, and to R rickettsii was 5%. A definitive exposure to R bellii was not observed, and the identification of the specific inciting rickettsia could not be established for 13% of the dogs, because of identical highest titers to 2 or more antigens. Our data indicate that canine exposure to R rhipicephali is prevalent in the eastern coastal region, whereas exposure to R montana takes place uniformly throughout the state. Rickettsia rickettsii exposure appears to be more prevalent in the central Piedmont region, but rarely is encountered in the western mountains. Regional seroprevalence for canine R rickettsii exposure approximates that for human exposure. Our findings support earlier suggestions that dogs may serve as environmental sentinels for establishing the geographic prevalence of foci of spotted fever.  相似文献   

11.
New endemic areas of spotted fever-like rickettsial disease have been found in south-eastern Australia (Gippsland, Victoria and Flinders Island, Tasmania). The rickettsia responsible is currently unknown although it may be Rickettsia australis. To investigate serological evidence of rickettsial exposure in various wild animal species, a competitive ELISA was developed which detected antibodies to R. australis. It was based on inhibition of an indirect ELISA detecting antibody to R. australis in guinea pig sera. Pre- and post-infection sera from 2 dogs, 2 rabbits, 5 mice and 6 rats, experimentally infected with R. australis, were tested by competitive ELISA. The results showed that all pre-infection sera were negative and all post-infection sera positive for antibody to R. australis. To test the utility of the competitive ELISA for detecting natural rickettsial infection in non-laboratory animals, 51 dog sera, negative for rickettsial antibody by immunofluorescence (IF) and 20 IF positive dog sera (collected from various locations on the east coast of Australia) were tested. Compared to the IF test the competitive ELISA was 90% sensitive and 96% specific. This new test has potential for detecting antibody to R. australis in the sera of different wild animal species.  相似文献   

12.
The kinetics of specific IgM and IgG antibody response was characterized in four 9-month-old Beagles after inoculation of 2 x 10(2) plaque-forming units (PFU) of Sheila Smith strain of Rickettsia rickettsii. Immunoglobulin M antibodies were first detected by indirect immunofluorescence on postinoculation (PI) day 9, peaked by PI day 20, and were no longer detectable by PI day 80. Immunoglobulin G antibodies became detectable between PI days 22 and 28, peaked by PI day 42, and decreased gradually through PI day 130. Subsequent challenges with R rickettsii on PI days 216 (2 x 10(2) PFU/dog) and 1,029 (5 x 10(4) tissue culture infective dose [TCID50]/dog) resulted in slightly different serologic responses. The initial challenge exposure failed to increase the concentration of IgG antibodies and induced only low concentrations of IgM antibodies. After the second challenge inoculation, IgM antibodies were not detectable and the concentration IgG antibodies increased slightly. Clinical abnormalities and seroconversion were documented in control dogs following each challenge exposure. Examination of acute and convalescent serum samples from 55 dogs in which Rocky Mountain spotted fever was suspected clinically suggested that sole evaluation of IgM antibodies in acute-phase serum would result in inaccurate diagnoses because of false-positive and -negative results. Use of a composite conjugate that detects IgM and IgG antibodies to R rickettsii appears to be satisfactory for diagnostic purposes; however, concurrent quantitation of IgM antibodies may facilitate serodiagnosis in a select group of dogs in which a four-fold increase in convalescent antibody titer is not detected by use of the composite conjugate.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

13.
This study was initiated to determine the degree of susceptibility of dogs to virulent and nonvirulent spotted fever-group rickettsiae and to evaluate dogs as sources of infection for ticks. Dogs were exposed either by inoculation (syringe) or by infective tick bite to the following rickettsial serotypes: (1) Rickettsia rickettsii (Wachsmuth and Sawtooth female 2 strains), (2) R montana (M/5-6 B strain), and (3) R rhipicephali (3-7-female 6 strain). Results indicated that dogs inoculated with 1,000 or 10,000 egg infective doses of virulent R rickettsii developed a rickettsemia that was detectable as early as 4 days after inoculation to as late as 10 days. Conversely, none of the dogs inoculated with R montana (M/5-6 B) or R rhipicephali (3-7-female 6) or exposed to ticks infected with these strains developed detectable rickettsemia, fever, or other observable clinical signs. None of the 394 ticks that fed on rickettsemic dogs (R rickettsii) infected by inoculation became infected, and only 3 of 348 ticks (0.9% infection rate) were infected after feeding on dogs which had been infected by tick bite. All ticks fed on dogs exposed to R rhipicephali and R montana were shown to be free of rickettsiae. The largest concentrations of plaque-forming units (PFU) in Vero cell culture from undiluted whole blood were found on day 6 and on day 7 in dogs that were inoculated with 10,000 and 1,000 R rickettsii, respectively, of the Sawtooth female 2 strain. The highest rickettsial concentration observed for the dog infected by tick feeding was on day 9.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

14.
Ctenocephalides felis were killed and collected from 92 cats in Alabama, Maryland, and Texas. The fleas and blood from the corresponding cat were digested and assessed in polymerase chain reaction assays that amplify DNA of Ehrlichia species, Anaplasma phagocytophilum, Neorickettsia risticii, Mycoplasma haemofelis, 'Candidatus M haemominutum' and Bartonella species. DNA consistent with B henselae, B clarridgeiae, M haemofelis, or 'Candidatus M haemominutum' was commonly amplified from cats (60.9%) and their fleas (65.2%). Results of this study support the recommendation to maintain flea control on cats in endemic areas.  相似文献   

15.
The purpose of this study was to determine whether there are associations between Bartonella species antibody (enzyme-linked immunosorbent assay (ELISA) and Western blot (WB)) and polymerase chain reaction assay results in cats with and without fever. Afebrile control cats (39/93; 42.0%) were more likely to have Bartonella species antibodies than cats with fever (29/93; 31.2%). The difference in prevalence of Bartonella species deoxyribonucleic acid (DNA) in blood of cats with fever (14/81; 17.3%) as compared to afebrile control cats (6/81; 7.4%) approached statistical significance (P=0.0571). Bartonella species ELISA or WB results frequently did not correlate to the presence or absence of Bartonella species DNA in blood. The results of this study indicate that in cats, Bartonella species antibody tests cannot predict whether fever is due to Bartonella species infection and should not be used to determine the Bartonella species infection status.  相似文献   

16.
The present research evaluated the presence of Rickettsia spp. on ectoparasites of horses and dogs (using PCR techniques), and their sera (using immunofluorescence assay) in El Valle de Antón town in Panama. A total of 20 horses and 20 dogs were sampled, finding four species of ectoparasites on dogs (the ticks Rhipicephalus sanguineus, Amblyomma ovale, Amblyomma oblongoguttatum, and the flea Ctenocephalides felis), and two tick species on horses (Amblyomma cajennense and Dermacentor nitens). DNA of Rickettsia amblyommii was found in pools of A. cajennense, D. nitens, and R. sanguineus, while Rickettsia felis was detected in C. felis pools. Overall, 70% (14/20) and 65% (13/20) of the horses and dogs, respectively, were seroreactive (titer ≥ 64) to spotted fever group rickettsiae. Sera from six dogs and five horses reacted to R. amblyommii antigens with titers at least four-fold higher than those for the other antigens tested (Rickettsia bellii, Rickettsia parkeri, Rickettsia rhipicephali, R. felis, and R. rickettsii). These serological results, coupled with our molecular findings, suggest that these dogs and horses were infected by Rickettsia amblyommii. More studies need to be realized afford to identify the Rickettsia species responsible for other serological and molecular positive results, and their ecological importance.  相似文献   

17.
Blood samples and ticks were obtained from dogs to assess canine exposure to spotted fever-group (SFG) rickettsiae during 1978-1980 in southern Connecticut. Of the 1,576 dog sera screened by microimmunofluorescence. 174 (11.0%) contained specific antibodies at titers greater than or equal to 1:64 against Rickettsia montana (n = 34), R rickettsii (n = 31), R rhipicephali (n = 19), or the unclassified 369-C rickettsia (n = 90). End points greater than or equal to 1:8,192 to R rickettsii and to R rhipicephali were recorded for 6 and 3 sera, respectively. Seropositivity rates from southwestern and southeastern Connecticut were similar (about 11%), with positive sera obtained from each region in nearly all months of the investigation. Rates were between 10% for dogs 2 to 7 years old and 14% for those greater than or equal to 8 years. Eight of 629 Dermacentor variabilis, 1 of 18 Ixodes dammini, and 2 of 3 Amblyomma americanum were positive by direct immunofluorescence for SFG rickettsiae. Thirteen D variabilis contained unidentified, long, bacillus-like organisms that differed from the short, ovoid (coccal) forms typical fo the spotted-fever agent, R rickettsii. With the exposure to infected ticks and production of type-specific antibodies against at least 4 SFG antigens, dogs may serve as suitable enzootic or epizootic indicators of rickettsial activity.  相似文献   

18.
OBJECTIVE: To determine whether dogs in New York, NY are naturally infected with Rickettsia akari, the causative agent of rickettsialpox in humans. DESIGN: Serologic survey. ANIMALS: 311 dogs. PROCEDURE: Serum samples were obtained from dogs as a part of a study on Rocky Mountain spotted fever and borreliosis or when dogs were examined at area veterinary clinics for routine care. Dog owners were asked to complete a questionnaire inquiring about possible risk factors at the time serum samples were obtained. Samples were tested for reactivity to spotted fever group rickettsiae by use of an enzyme immunoassay (EIA). Twenty-two samples for which results were positive were tested by use of an indirect immunofluorescence antibody (IFA) assay followed by confirmatory cross-absorption testing. RESULTS: Results of the EIA were positive for 24 (7.7%) dogs. A history of tick infestation and increasing age were significantly associated with whether dogs were seropositive. Distribution of seropositive dogs was focal. Seventeen of the 22 samples submitted for IFA testing had titers to R rickettsii and R akari; for 11 of these, titers to R akari were higher than titers to R rickettsii. Cross-absorption testing indicated that in 6 of 7 samples, infection was caused by R akari. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that dogs can be naturally infected with R akari. Further studies are needed to determine the incidence of R akari infection in dogs, whether infection is associated with clinical illness, and whether dogs can serve as sentinels for human disease.  相似文献   

19.
Canine Rocky Mountain spotted fever: a kennel epizootic   总被引：2，自引：0，他引：2  
Within a period of 5 consecutive days after the initial observation of illness was made, 7 of 12 Siberian Husky dogs developed clinical signs of Rickettsia rickettsii infection. One dog died and was necropsied. Clinical signs of infection consisted of lethargy, anorexia, ocular and nasal discharges, and neurologic disorder (incoordination and rolling). Scleral blood vessel injection, fever, lymphadenomegaly, splenomegaly, and increased bronchovesicular lung sounds were prominent findings. Clinical laboratory test results identified decreased platelet numbers, variable neutrophil counts, increased serum alkaline phosphatase activity, hyponatremia, hypokalemia, and bilirubinuria. Diagnosis of Rocky Mountain spotted fever was confirmed by serologic evaluation of acute and convalescent sera, using the micro-immunofluorescence technique, and R rickettsii antigen was determined by demonstration of intracellular rickettsial organisms in vascular endothelial cells of brain and lung (stained with carbol-basic fuchsin and aqueous malachite green) and by demonstration of spotted fever-group rickettsiae in tissues by direct fluorescent antibody technique. Near-simultaneous naturally occurring tick-borne infection of 7 dogs with R rickettsii documents an unreported occurrence.  相似文献   

20.
Although cats and their arthropod parasites can sometimes be important sources of zoonotic diseases in humans, the extent of exposure among various cat populations to many potential zoonotic agents remains incompletely described. In this study, 170 domestic cats living in private homes, feral cat colonies, and animal shelters from California and Wisconsin were evaluated by serology to determine the levels of exposure to a group of zoonotic vector-borne pathogens. Serological positive test results were observed in 17.2% of cats for Rickettsia rickettsii, 14.9% for R akari, 4.9% for R typhi, 11.1% for R felis, and 14.7% for Bartonella henselae. Although vector-borne disease exposure has been documented previously in cats, the evaluation of multiple pathogens and diverse cat populations simultaneously performed here contributes to our understanding of feline exposure to these zoonotic pathogens.  相似文献   

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