Canine isosporosis - epidemiology of field and experimental infections.

Isospora spp. are the causative agents of canine isosporosis. Of the 3590 diagnostic samples from Austrian dogs (< or = 2 years old), 8.7% contained Isospora oocysts, 78% of which from dogs up to 4 months of age. Non-haemorrhagic and haemorrhagic diarrhoea were significantly more prevalent in Isospora-infected animals than in coccidia-negative ones. Twelve of 15 litters from a large commercial dog breeding unit (examined from the third to the 10th week of life) also excreted Isospora (average prevalence: 36.4%) in intensities from 333 to 35,000 oocysts per gram of faeces (opg). In experimental trials 26 3-week-old Beagle puppies were infected with low (600-6000), medium (10,000) or high (20,000) dose of Isospora ohioensis-group or Isospora canis field isolates. Additionally 21 puppies were infected as above and treated with a symmetrical triazintrione. Parasitological and clinical parameters were examined. The two Isospora species differed significantly concerning intensity and duration of excretion. The pre-patent period was 6-7 days for I. ohioensis and 10-12 days for I. canis. The latter species showed significantly longer excretion and higher opg. This was not influenced by simultaneous infections with both species. Individual patterns of faecal consistency were very variable, irrespective of the infection dose. Treatment significantly reduced both the intensity and the duration of oocysts excretion as well as diarrhoea in comparison with the infected, untreated group and thus proved to be effective against coccidiosis in experimental infections.

Clonal cultures of Histomonas meleagridis, Tetratrichomonas gallinarum and a Blastocystis sp. established through micromanipulation.

Clonal cultures of Histomonas meleagridis, Tetratrichomonas gallinarum and a Blastocystis sp. were established for the first time. Single microbes were successfully isolated from a mixture of micro-organisms obtained from caecal contents of turkeys, using a micromanipulation approach. The cloned parasites were propagated in vitro and maintained through continuous passages multiplying to high numbers. Identification of the protists was done by morphological investigation identifying various forms of each parasite. PCR and partial sequencing of the small subunit rRNA were used to confirm clonality and to determine the relationship of the cloned parasites with known protozoan parasites. The clonal cultures established by this technique will be useful to gain more insight into the biological repertoire of the organisms. In addition, refined infection experiments in different poultry species can now be performed to elucidate the pathological pathways of the respective protozoa.

Echinococcus multilocularis in Austrian foxes from 1991 until 2004.

The prevalence rates of Echinococcus multilocularis in foxes (n=5600) evaluated in several Austrian surveys conducted between 1991 and 2004 were analysed for spatial and temporal differences. Data from early studies (1993-1997) in which the intestinal scraping technique (IST) was utilized were compared with data from recent (1999-2004) investigations, which made use of the shaking in a vessel technique (SVT), and it was assessed whether or not the infection rates of Austrian foxes had increased between the investigated intervals. In total, data from 85 districts are presented and both the retrospective and recent data are available from 39 of these districts. A Bayesian hierarchical model of parasite prevalences is presented which (i) accounts for differences in the sensitivity of IST and SVT, (ii) incorporates spatial auto-correlation between neighbouring districts, (iii) investigates the possibility of a temporal shift in the infection status of foxes, and (iv) quantifies uncertainty at each level of the model. The national average prevalence rates in the mid-1990s and at the turn of the millennium were 2.4% (95% confidence intervals 1.1-4.8) and 3.9% (95% confidence intervals 1.5-8.4) respectively. Above average prevalence rates were observed in the western and the northern parts of the country. Evidence is also presented for a temporal augmentation of the prevalence rates in some districts in the northern and eastern parts of the country. These findings are in concordance with several investigations in other European states where both newly emerged areas and elevated levels of transmission in existing endemic areas have been found. None of the districts investigated here showed significant evidence of a drop in prevalence.

Epidemiology of Eimeria infections in an Austrian milking sheep flock and control with diclazuril.

In a flock of milking sheep from Styria (Austria), the dynamics of Eimeria oocyst excretion was monitored in the lambing season 2003-2004 and a treatment trial with 1 mg/kg diclazuril (single dose on day 0 of study) was conducted in two groups of early weaned lambs. Adult animals (n = 30 ewes, 30 yearlings) excreted oocysts of different species (weekly prevalences from week -7 ante partum to week 5 post-partum: ewes 20-60%, yearlings 38-73%) in low intensities (< or = 6000 oocyst per gram of faeces, highest values in weeks -1 and -4) without clinical signs. Ewes excreted significantly fewer oocysts than yearlings. Lambs in the first group (n = 32 treated animals, 32 controls) excreted oocysts from the seventh day of sampling (average age on day 0: 28 days), those in the consecutive group (n = 32 treated animals, 30 controls) already excreted oocysts on day 0 (average age: 34 days). Treatment resulted in significant reduction of the overall excretion rates on days 7-21 of study compared with untreated controls. Similarly, the excretion intensities were significantly reduced in the treated groups. Overall excretion rates of the pathogenic species (Eimeria ovinoidalis, Eimeria bakuensis, Eimeria weybridgensis/Eimeria crandallis, Eimeria ahsata) were significantly reduced after treatment. Soft faeces and anal soiling in the lambs were significantly reduced and weight gain was increased. A single treatment of lambs with diclazuril before or shortly after the onset of oocyst shedding was sufficient to control oocyst excretion and improve animal health.

Toxoplasmosis in Pallas' cats (Otocolobus manul) raised in captivity.

Manuls or Pallas' cats (Felis manul, syn. Otocolobus manul) are endangered wild cats from Central Asia kept and bred in many zoos. Despite good breeding success young cats frequently die from acute toxoplasmosis. From 1998 to 2002, a breeding pair in the Schönbrunn Zoo in Vienna, Austria, gave birth to 24 kittens; 58 % of kittens died between the 2nd and the 14th week of life, mostly due to acute toxoplasmosis. The epidemiology of toxoplasmosis in Pallas' cats was examined and a control strategy to protect the kittens from fatal toxoplasmosis was developed. One 12-week-old kitten from a litter of 6 born in 2001 died of generalized toxoplasmosis. This kitten had shed T. gondii oocysts that were bioassayed in mice. Toxoplasma gondii was isolated in tissue culture inoculated with tissues of these mice. The surviving animals were immediately treated with clindamycin for 16 weeks; they acquired a natural infection and seroconverted by the end of this time without clinical signs.

Occurrence of Isospora suis in Germany, Switzerland and Austria.

Nationwide surveys for the occurrence of Isospora suis were carried out in Germany, Austria and Switzerland including a questionnaire regarding herd size, health status and management practices and a coccidiosis sampling kit for pooled faecal samples from litters of suckling piglets. A total of 184 veterinary practices participated in the survey and returned 1745 samples (331 kits) from 324 farms in the north (n = 98), south (n = 84), centre/east (n = 42) and west (n = 10) of Germany, Austria (n = 61) and Switzerland (n = 29) with larger farms in north and centre/east (average number of sows: 270 and 500) and smaller ones in the south (95), Austria (60) and Switzerland (43). Larger farms tended to have better hygienic standards (slatted floors, disinfection of the farrowing units). The majority of the participating farms (93.5%) reported problems with diarrhoea in piglets at 2-3 weeks of age, significantly associated (P < 0.001) with uneven weaning weights (94.9%). Toltrazuril (5%; Baycox) was used only rarely; however, in these farms unevenness of weaning weights was less frequently observed (P = 0.011). A 76.2% of the farms were positive for I. suis (samples contained mostly low or moderate oocyst numbers), especially in the south (P < 0.001). Oocysts were more frequently found in samples from farms with reported diarrhoea (P = 0.011), uneven weight gain (P = 0.019) or in herds of small size (P < 0.001). Disinfection, floor type or treatment with toltrazuril did not affect the frequency of observation of oocysts.

Prevalence of antibodies against Neospora caninum and Toxoplasma gondii in dogs and foxes in Austria.

Sera from 1770 dogs and 94 red foxes from Austria were examined for antibodies against Neospora caninum using the indirect immunofluorescent antibody test (IFAT). 3.6% of the dogs were seropositive with titres ranging from 1:50 to 1:6400. Dogs from rural areas were significantly more often seropositive for N. caninum than those from the urban area of Vienna (5.3% versus 2.1%). There were no significant differences in sex or breed, but a slight increase in seropositivity with age was apparent, indicating postnatal infection. None of the foxes had antibodies against N. caninum. Additionally, sera from 242 dogs and 94 foxes were examined for antibodies against Toxoplasma gondii using the IFAT. Thirty-five percent foxes and 26% of the dogs were positive; 1.7% of the dogs were positive for both parasites. This is the first report of the prevalence of N. caninum infections in dogs and foxes in Austria.

A spontaneous and fatal jejunal intussusception in a European brown hare associated with Eimeria leporis.

A recently dead adult female European brown hare (Lepus europaeus Pallas) was found in the wild with no evidence of trauma or external injury. Necropsy revealed symptoms consistent with endotoxic shock and a haemorrhagic jejuno-jejunal intussusception with a necrotic intussusceptum. Small, unattached nodules were present extensively in the jejunal lumen and within the intussuscipiens. These nodules proved to be masses of unsporulated Eimeria leporis oocysts. Review of the literature reveals E. leporis to be a common parasite of wild hares, with protracted pathogenic potential under some circumstances. This is the first report of intussusception in this species and the most severe lesion seen associated with E. leporis. This case suggests that E. leporis may be more harmful to the wild European brown hare population than previously supposed.

Detection of the protozoan Neospora caninum using in situ polymerase chain reaction.

A new method to detect the protozoan Neospora caninum using indirect in situ polymerase chain reaction (PCR) is described. In situ PCR combines the advantages of the extraordinarily high sensitivity and specificity of PCR and the in situ representation of immunohistochemical methods. We describe an indirect in situ PCR, whereby the amplified products were detected using a primed in situ (PRINS) reaction with hapten-labeled nucleotides and visualized using fluorochrome-labeled antibodies. This technique was carried out in both infected cell cultures and formalin fixed, paraffin embedded tissues. Clear signals were obtained in the N. caninum positive samples using in situ PCR, whereas control slides with Toxoplasma gondii infected tissues always yielded negative results.

Serological detection of Capillaria hepatica by indirect immunofluorescence assay.

In this paper, a serological assay for the detection of antibodies to Capillaria hepatica, a zoonotic parasite, is described. In the past, the only way of detecting Capillaria hepatica was to perform a liver biopsy. The indirect immunofluorescence (IIF) assay, based on liver sections of naturally infected mice and human serum samples, is suitable for detecting early stages of human infections and for screening purposes. No cross-reactivity with other parasitic infections was detected. We have applied the IIF assay to serum samples of 60 employees of the Zoological Garden of Vienna, Schönbrunn, Austria, and found one positive and one questionable sample.

Monthly and seasonal fluctuations in abomasal nematode worm burden of naturally infected cattle in Austria.

From October 1980 until September 1981, 191 abomasa of naturally infected cattle were obtained from the slaughter-houses of Mürzhofen and Graz in the province of Styria, and of Wiener Neustadt in the province of Lower Austria and examined to study the monthly and seasonal occurrence of hypobiosis in Ostertagia ostertagi and Trichostrongylus axei. Infections in pastured animals (cows, steers and heifers) were compared with those in stabled animals (bulls fed on green forage and silage). Except for 10 bulls fed on silage all animals were parasitized. The results indicate that in Austria inhibited early fourth stage larvae of Ostertagia accumulate during the winter. Pastured animals showed a higher intensity of infection than stabled animals. Cows less than 3 and greater than 5 years of age had higher worm counts than those between these ages. There was a simultaneous accumulation of third stage larvae and adult worms of Trichostrongylus axei in autumn in steers and heifers. In bulls fed on green forage a higher adult worm burden was seen in winter. No significant correlation existed between the number of worm nodules in the abomasal mucosa and the various developmental stages of the worms. The count of in-utero immature eggs was higher in stabled than in pastured animals. No significant correlation between the number of in-utero eggs and that of female worms was noticeable. Numbers of mature Ostertagia eggs rose in spring, while in fall and winter the immature eggs predominated. An increase in the uterine egg count was observed in Trichostrongylus in autumn. Statistical analyses of our data show that the most decisive factor influencing the numbers of inhibited and adult Ostertagia as well as in-utero eggs is the system of animal management.

[Trombiculid mite--Neotrombicula autumnalis (Shaw 1790)--in veterinary medicine. Nervous systems in dogs following massive infestation]. / Zur Bedeutung der Herbstgrasmilbe--Neotrombicula autumnalis (Shaw 1790)--in der Veterinärmedizin: Nervale Symptome bei Hunden nach massiver Infestation.

Initially the biology of chigger mites and the clinical course of Trombiculosis is reviewed. This is followed by a case study dealing for the first time with nervous symptoms associated with this disease. Twenty-four hours after a massive infestation of at least 2000 larvae of N. a. autumnalis two male Yorkshire terriers of approximately three years of age showed initial stages of paresis of the rear extremities in a few hours. The lameness worsened to such an extent that the front extremities were also affected and the dogs could no longer stand. After repeated acaricide treatments and symptomatic therapy these nervous symptoms disappeared within three days.

[Diagnosis of an infestation with Collyriclum faba (Bremser, 1831) in a starling (Sturnus vulgaris L.) in Vienna]. / Nachweis eines Befalles mit Collyriclum faba (Bremser, 1831) bei einem Star (Sturnus vulgaris L.) in Wien.

A massive infestation with Collyriclum faba (Bremser, 1831) was found in a young starling from Vienna. Always two trematodes formed cysts mainly in the subcutaneous tissues around the cloaca. In the presented starling there were additional cysts on the inner surface of the abdominal and thoracical wall, in the lung and on the rectum.

Morantel sustained release bolus: a new approach for the control of trichostrongylosis in Austrian cattle.

The efficacy of a morantel sustained release bolus to control gastrointestinal parasitism during two consecutive grazing seasons was assessed in replacement dairy heifers raised under field conditions in Austria. Thirty calves were randomly allotted into two equal groups and maintained throughout the 1979 summer pasturing season on adjacent pastures of equal size with identical grazing history. Twenty-four of the thirty calves used in 1979 were monitored throughout 1980, each animal remained in the same treatment group as the previous year and grazed the same pastures as the previous year. In both 1979 and 1980 the bolus was administered to each animal in the treated group one week before turnout onto spring pastures, while the control animals received no anthelmintic treatment during either year. The efficacy of the bolus was assessed by comparison of faecal worm egg counts, herbage larval counts, worm counts from tracer and principal trial animals, weight gains and by the incidence of clinical disease found in both tracer and trial animals throughout the grazing season. Milk production was also monitored for all animals in both treatment groups during the first lactation. The system of treatment used in the present study with the morantel sustained release bolus was highly effective in preventing a significant buildup of infective larvae on pasture to the end of the grazing season in both years. In 1979 worm counts of tracer calves grazed on the treated pastures in mid-August were similar to those recorded at the beginning of the season, while worm counts in the control tracers were five times the total found at the beginning of the season. In 1979 the bolus-treated calves outperformed the control group by 34.8 kg (P less than 0.001) over the 168-day grazing period. These results demonstrated that administration of the bolus to calves at the time of turnout onto spring pastures was most effective both in controlling parasites within the cattle themselves and in reducing the level of parasite contamination. During the second grazing season (1980) no beneficial effect in weight gain was observed due to the second bolus treatment. Weight gains realized during the first year, however, largely remained through the second year and the bolus-treated heifers reached breeding weight on average 19 days earlier. No difference in milk yield was observed between the treated and control animals during thier first year of lactation.

[Seasonal rhythm of the discharge of Dictyocaulus viviparus, Varestrongylus sagittatus and Elaphostrongylus cervi larvae from the red deer (Cervus elaphus)]. / Jahresrhythmus in der Larvenausscheidung von Dictyocaulus viviparus, Varestrongylus sagittatus und Elaphostrongylus cervi bei Rotwild (Cervus elaphus).

The discharging of the first larvae of Distyocaulus viviparus, Varestrongylus sagittatus and Elaphostrongylus cervi is regulated by a seasonal rhythm. This rhythm was studied in a deer population of 150 +/- 10 animals over a period of 4 years. The maximum discharges of D. viviparus are in May and June and those of the 2 other species are in the time from February to April. Very good results of treatment were achieved with 3 X 7.5 mg and 5 X 3 mg Fenbendazole/kg live weight against D. viviparus and E. cervi. A dose of 5 X 3 mg Fenbendazole proved to have quite a good effect against V. sagittatus. The most favourable time of treatment is late November or early December.