Renate Edelhofer

Use of purified tachyzoite surface antigen p38 in an ELISA to diagnose bovine neosporosis

Affinity-purified 38 kDa surface antigen of Neospora caninum tachyzoites was used to develop an enzyme-linked immunosorbent assay (ELISA) to diagnose N. caninum-associated abortion in cattle. The specificity of this antigen was demonstrated by using sera from cattle experimentally infected with other apicomplexan parasites. In a panel of field sera, serological differences could be demonstrated between herds with epidemic and endemic abortions. Optimal ELISA cut-offs were determined for the detection of association between seropositivity and abortion in herds with N. caninum-associated abortions. These optimal cut-offs differed markedly when only sera from either endemic or epidemic cases were used for cut-off determination. It may thus be appropriate to apply different cut-offs in serological tests depending on the abortion pattern to be analysed.

Clinical symptoms and diagnosis of encephalitozoonosis in pet rabbits.

Infections with Encephalitozoon cuniculi in rabbits are observed at increasing frequency and are known as opportunistic infections in immunocompromised humans. 191 pet rabbits with suspected encephalitozoonosis, presented at the Animal Hospital of the Veterinary University of Vienna (Austria), were included in this study. Rabbits were serologically examined for antibodies against E. cuniculi (144 positive out of 184 rabbits with suspected encephalitozoonosis compared to 14 positive out of 40 clinically healthy rabbits tested as part of a standard health check) and Toxoplasma gondii (8 positive out of 157). Of the 144 seropositive rabbits with clinical signs, 75% showed neurological symptoms, 14.6% demonstrated phacoclastic uveitis and 3.5% suffered from renal failure. 6.9% of the animals had combined symptoms. Vestibular disease dominated within the rabbits that showed neurological symptoms. Polymerase chain reaction (PCR) could not detect parasite DNA in urine or cerebrospinal fluid (CSF), but did so in 4 out of 5 samples of liquefied lens material in cases with phacoclastic uveitis due to lens capsule rupture. Additionally further diagnostic procedures, such as inspection of the external ear canal (N=69), radiography of the tympanic bullae (N=65) were performed to rule out differential diagnosis. 54.2% of the patients exhibiting neurological symptoms recovered within a few days, while 87.5% of the rabbits suffering from renal failure died or had to be euthanized.

Prevalence of antibodies against Toxoplasma gondii in pigs in Austria--an evaluation of data from 1982 and 1992.

To obtain information on the prevalence of antibodies againstToxoplasma gondii in pigs in Austria, 4697 blood samples from pigs were collected in the years 1982 and 1992 and tested by an indirect fluorescence antibody test. The results of the studies show that due to modern fattening systems the prevalence of infections withT. gondii in slaughtered pigs has obviously decreased in Austria during the last 10 years. The investigations indicate a significant difference in the rate of infection fection of pigs between 1982 (13.7%) and 1992 (0.9%). Additionally, the prevalence ofT. gondii antibodies in breeding sows (1982, 43.4%; 1992, 4.3%) was higher than that in fattening pigs (1982, 12.2%; 1992, 0.8%).

Seroprevalence of Toxoplasma gondii and Neospora caninum infection of cats in Hungary.

Blood samples were collected from 330 cats in Hungary in order to evaluate their seroconversion to Toxoplasma gondii and Neospora caninum using the indirect fluorescent antibody test (IFAT). The overall prevalence of toxoplasmosis was 47.6%, the prevalence being 22.4% among urban, 50% among suburban and 61.3% among rural animals. Significantly more cats had high IFAT titres (1:640 to 1:5120) in the countryside. Female cats were more frequently infected with T. gondii than males (53.3% vs. 39.3%), and seropositivity increased with the age of animals. The prevalence (0.6%) and titre (1:40) of antibodies to N. caninum was low. Sixty-two cats were also screened for seroconversion to feline infectious peritonitis (FIP) virus. Higher titres to T. gondii were more frequently detected among FIP-positive cats, but this difference was non-significant due to the small number of cats with concurrent infection.

Evaluation of a commercial ELISA kit for detection of antibodies against Toxoplasma gondii in serum, plasma and meat juice from experimentally and naturally infected sheep

BackgroundToxoplasmosis is one of the most common food borne zoonoses worldwide, and can be a serious life-threatening disease in the congenitally infected fetus and in immunosupressed patients. Among food animals, sheep along with goats and pigs possess the highest incidence of T. gondii cysts in meat, and play a major role as a source of human infection.MethodsIn this study, a new commercial ELISA kit (PrioCHECK® Toxoplasma Ab SR, Prionics Schlieren-Zurich, Switzerland) for the detection of anti-T. gondii antibodies in serum, plasma and meat juice of sheep, was evaluated by comparing it with the indirect fluorescent antibody test (IFAT), indirect haemagglutination test (IHA) and real-time PCR, on samples from experimentally inoculated and naturally exposed sheep.ResultsThe commercial ELISA detected the infection status in 50% and 100% of sheep orally inoculated with 10,000 T. gondii oocysts (n = 6), from two or three weeks post infection (wpi), respectively, both on serum and plasma samples. Meat juice from all experimentally inoculated sheep collected at slaughter (12 wpi) showed positive ELISA values. In naturally exposed sheep (n = 396), the ELISA showed a very good agreement with IFAT (kappa = 0.91-1.0) and IHA (kappa = 0.96-1.0) performed on serum; and a positive correlation was observed between ELISA values and IFAT titers. By a Receiver Operating Characteristics (ROC) curve analysis, the commercial ELISA had relative sensitivities between 93.33% and 100%, and relative specificities between 96.87% and 100% respect to IFAT and IHA, depending on the considered cut-off value and animal groups tested. Furthermore, the ELISA correctly recognized all animals reacting positive in real-time PCR. The ELISA results on meat juice agreed with those on serum samples in all experimentally inoculated animals, and in 94 out of 96 (97.9%) naturally exposed sheep, when meat juice was tested at a 1:10 dilution.ConclusionThe commercial ELISA kit evaluated in this study could represent a valuable tool to improve the surveillance and reporting system for T. gondii in sheep populations at the farm level or for diagnosis at the slaughterhouse, contributing to the control of this widespread zoonosis.

Seroprevalence of canine babesiosis in Hungary suggesting breed predisposition

Six hundred fifty-one blood samples were collected from urban and rural dogs in various parts of Hungary to measure antibody levels to Babesia canis with indirect fluorescent antibody test. Thirty-seven (5.7%) of the sera showed positivity with titers between 1:80 and 1:10,240. Seroconverted dogs were found in 13 locations of the country. It is concluded that canine babesiosis is becoming more prevalent in Eastern Hungary. Seropositivity increased then declined with age, reaching a maximum in case of 3.1- to 5-year-old dogs. Prevalence of antibodies to B. canis was significantly higher among german shepherds and komondors. This suggests a genetic predisposition of german shepherd dogs to chronic babesiosis (carrier status) with long-term maintenance of their seropositivity. On the other hand, heavy-coated komondors are phenotypically more suitable for repeated exposure to ticks, potentially infected with B. canis. This is the first report on the seroprevalence of canine babesiosis in Hungary.

Babesia divergens-like organisms from free-ranging chamois (Rupicapra r. rupicapra) and roe deer (Capreolus c. capreolus) are distinct from B. divergens of cattle origin – An epidemiological and molecular genetic investigation

In 2005 and 2006, three adult female chamois (Rupicapra r. rupicapra) were found dead with signs of acute babesial infection in the eastern Swiss Alps. PCR on DNA extracted from blood or spleen of the carcasses revealed sequence identity of the amplified part of the 18S rRNA gene with GenBank entries attributed to Babesia divergens of cattle origin or B. capreoli of wild ruminant origin which have never been described before in this region. Examination of 424 blood samples from 314 head of cattle from this area by IFAT, microscopy and PCR provided no evidence for babesial infection. Six of 887 ticks collected from cattle were PCR-positive, and sequencing revealed Babesia sp. genotype EU1 in five and B. divergens/B. capreoli in one of them. A Babesia isolate of chamois, two isolates of roe deer from the same region and one isolate of a roe deer from the north-western Swiss Alps were genetically compared with two Swiss B. divergens isolates of cattle origin by analysing the genomic rDNA locus. Whereas the near full length sequences of the 18S rRNA gene were virtually identical among all six isolates (>99.4% identity), distinct differences between the two isolates from cattle on the one hand and the four isolates from free-ranging ruminants on the other hand were observed in the sequences of the internal transcribed spacers 1 and 2 (ITS1, ITS2) and part of the 28S rRNA gene. These results indicate that, albeit genetically very closely related, these babesial organisms from cattle and from free-ranging ruminants indeed are distinguishable organisms with different host specificities, and they support the use of the discrete species name B. capreoli for the B. divergens-like organisms from chamois and roe deer.

Imported non-endemic, arthropod-borne and parasitic infectious diseases in Austrian dogs

ZusammenfassungHINTERGRUND: Die steigende Anzahl von nach Österreich importierten, nicht endemischen, durch Arthropoden übertragenen und seltenen parasitären Infektionserkrankungen bei Hunden ist die Grundlage für diese Studie. METHODEN: Die Anzahl und der Auslandsaufenthalt der Hunde, sowie die Infektionen wurden bei 174 Hunden an der Veterinärmedizinischen Universität Wien dokumentiert. Symptomatische Hunde mit bekannter Herkunft oder Aufenthalt im Ausland wurden in die Studie inkludiert. Die Hunde wurden auf Leishmaniose, Ehrlichiose, Dirofilariose und Rickettsiose getestet. ERGEBNISSE: Neben der caninen Leishmaniose, der Ehrlichiose, der Herzwurminfektion und der kutanen Filariose wurden Infektionen mit Rickettsia conorii, Cordylobia anthropophaga und Pentastomiden in 47% der Fälle diagnostiziert. Mischinfektionen traten bei 10% der untersuchten Hunde auf. SCHLUSSFOLGERUNGEN: Das Verbringen von nicht endemischen Erregern und deren Vektoren nach Österreich stellt ein zunehmendes Risiko für diese Hunde dar. Eine direkte Übertragung vom Hund auf den Menschen ist unwahrscheinlich und die relevantesten Vektoren sind in Österreich nicht heimisch. Eine mögliche Steigerung des Risikos in Österreich könnte aus der weiteren Zunahme von importierten Hunden gemeinsam mit infizierten Vektoren resultieren. Zusätzlich steigt die Wahrscheinlichkeit einer Endemisierung von neuen Vektoren bei anhaltender Klimaerwärmung.SummaryBACKGROUND/AIMS: An increasing number of imported non-endemic arthropod-borne diseases and other rare parasitic diseases in dogs in Austria were the basics for this report. Number and species of imported pathogens as well as the origin of the carrying dogs were of special interest. METHODS: Symptomatic dogs that have been in a foreign country before were included to the study. 174 dogs, presented at the Veterinary University of Vienna, were analysed for their origin or stay in a foreign country (n = 26) and type of infection. The age and breed distribution was recorded. Dogs were tested for leishmaniosis, ehrlichiosis, filariosis and infection by Rickettsia conorii. RESULTS: Overall infection rate was 47% in the tested dogs. Mixed infections were diagnosed in 10% of dogs included. Infestation by Cordylobia anthropophaga and Pentastomida was documented. CONCLUSIONS: The introduction of non-endemic pathogens, and sometimes their vectors, by dogs is documented in Austrian dogs. Direct transmission from dogs to humans is very unlikely and most of the vectors (Phlebotomus spp.) are not native in Austria. A future risk may arise from an increasing number of imported dogs, carrying these vectors that may be host to various pathogens, to areas still free of those pathogens. A further problem is the probability, that these vectors may become native when climate conditions are going to be favourable to them.

Improved disease resistance after Babesia divergens vaccination.

Abstract The efficacy of a new inactivated vaccine against Babesia divergens was evaluated by means of inoculation tests. The infection was initiated by i.v. injection of blood containing 2 × 109 living parasites into splenectomized and non-splenectomized calves. Clinical status and hematological parameters were determined. Serology examinations for antibodies against B. divergens were carried out by indirect fluorescent antibody test (IFAT). Non-vaccinated and splenectomized animals exhibited experimental infections. In vaccinated and splenectomized animals, clinical symptoms and prolonged incubation periods were observed.

SEROLOGICAL EVIDENCE FOR BABESIA CANIS INFECTION OF HORSES AND AN ENDEMIC FOCUS OF B. CABALLI IN HUNGARY

In order to evaluate the seroconversion of horses to Babesia caballi and B. canis in Hungary, blood samples were collected from 371 animals on 23 different locations of the country. The presence of antibodies to B. caballi was screened with a competitive ELISA. All 29 positive samples came from one region (the Hortobágy). The prevalence of infection did not show correlation with sexes, and reached 100% in the age group of 2-5 years. Babesia canis-specific antibodies were demonstrated by IFAT in 6.74% of animals kept in 7 regions. The titres were low or medium level (1:40 to 1:160), indicating that the horses had previously been exposed to this piroplasm, but their infection must have been limited. The highest seropositivity rate was observed in the age group of 3-4 years, and males (stallions and geldings) were significantly more frequently infected than females. However, neither B. caballi nor B. canis could be identified in the peripheral blood samples of infected horses by PCR. Since most of the B. caballi-positive horses remained negative in the B. canis IFAT, whereas seroconversion solely to B. canis was detected in several regions of the country, serological cross-reaction between the two species can be discounted. This is the first serological evidence of horses being naturally infected with B. canis, supporting the view that piroplasms are less host specific than previously thought.