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Biomedical subjects

A Joachim

Publications and source records attributed to A Joachim.

At least 19 recordsLinked to original sources
PubMed2006

Efficacy of various anticoccidials against experimental porcine neonatal isosporosis.

The efficacies of 20 mg/kg body weight (BW) of toltrazuril (Toltra) 2 days post-infection (dpi), 2 mg/kg BW of diclazuril 2 and 3 dpi and 200 mg/kg BW of sulphadimidine 2, 3 and 4 dpi were compared in a model for piglet isosporosis. Weight gain (first 4 weeks of life) and diarrhoea and oocyst excretion from 4 to 11 dpi were evaluated (10-12 piglets/group). Additionally, animals were killed and examined for pathohistological changes of the small intestines 5, 7, 11 and 14 dpi (n = 3 per group and time point) and lengths of the intestinal villi. Diarrhoea (semi-liquid or liquid faeces) was seen from 5 dpi in all groups except Toltra, and the differences in prevalence and intensity of diarrhoea were statistically significant (p < 0.05) between Toltra and the other groups, which were similar (trial 1). Oocyst excretion was greatly reduced in the Toltra group, which was also statistically significant for the mean and median excretion rates and the percentage of excreting piglets between Toltra and the other groups (p < 0.05). Weight gain was highest in Toltra (p < 0.05). Histopathology revealed mostly villous necrosis and atrophy in the small intestines except the duodenum, which peaked at 7 dpi, in all groups except Toltra. Between 5 and 11 dpi, the Toltra group had significantly longer villi than the other groups. Reduced weight gain and diarrhoea caused by Isospora suis was controlled by a single application of Toltra in the pre-patent period, while neither diclazuril nor sulphadimidine improved the clinical picture of isosporosis.

Animals↗
PubMed2006

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.

Animals↗
PubMed2006

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.

Animals↗
PubMed2005

Isospora suis: an experimental model for mammalian intestinal coccidiosis.

Piglets experimentally infected with 10,000 oocysts of Isospora suis in three identical trials (n = 50) were examined clinically and coproscopically from 5 to 11 days post-infection (d.p.i.), weighed in weekly intervals until the fourth week of life and compared to age-matched asymptomatic controls (n = 17). Furthermore, 17 infected piglets were histologically examined on days 5-14 p.i. Infected animals had a significantly lower weight gain than the controls and showed diarrhoea throughout, with maximum prevalence and intensity on 6 d.p.i. Half of the animals had diarrhoea for only 2 days or less. The number of diarrhoea days was negatively correlated with weight gain. Oocyst excretion started on 5 d.p.i. with peak prevalences and declined afterwards; a smaller peak was seen on 10 d.p.i. All animals excreted parasites at least once, and most of them excreted for 5-7 days. Oocyst excretion intensity paralleled the prevalence and ranged from 220 to 251,501 oocysts per gram of faeces (opg). Most samples contained 4 x 10(3) to 4 x 10(4) opg. The opg values were negatively correlated with faecal scores (samples with diarrhoea contained less oocysts) of the same day and the previous day. Histologically, necrosis followed by atrophy of the villi was most pronounced in the early stage of infection throughout the jejunum and ileum but declined thereafter. On 14 d.p.i., villous atrophy was still noticeable in the jejunum. Histology is difficult to quantify and requires large animal numbers, although the effects are visible for some time. Weight gain and faecal score can be affected by other factors than parasite infection. From the compiled data, we conclude that the established model is suitable to study piglet isosporosis with oocyst excretion being the most reliable parameter, although individual variations are considerable. A negative correlation between excretion and diarrhoea may be responsible for the difficulties in the detection of the parasite in field samples.

Animals↗
PubMed2005

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.

Animals↗
PubMed2005

Ecdysis of Oesophagostomum: possible involvement of eicosanoids and development of a bioassay.

Bioassays were developed and applied to test the role of eicosanoids and pH changes in ecdysis of Oesophagostomum dentatum. Exsheathment (80-100%) was achieved by subjecting third-stage larvae (L3) either to chlorine (hypochlorite assay) for 5 min or by incubating them in HCl followed by addition of NaHCO3 (pH-change assay) with subsequent cultivation at 38.5 degrees C/10% CO2 for 1 week. Addition of the lipoxygenase (LOX) inhibitor diethylcarbamacine (DEC) to the larvae resulted in a reduction of the exsheathment rates which could be restored by the addition of leukotrienes (LT)B4, LTC4, LTD4 and LTE4. Addition of the cyclooxygenase (COX) inhibitor acetylsalicylic acid (ASA) also resulted in decreased exsheathment rates both in the hypochlorite and in the pH-change assays in a dose-dependent manner. However, the primary COX products (prostaglandins) were not able to reverse this effect, in contrast to LTC4. It was concluded that: (1) both tests are suitable for bioassaying the effect of substances on exsheathment, and (2) eicosanoids involved in the control of exsheathment of L3 of O. dentatum are primarily LT.

Animals↗
PubMed2005

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.

Animal Husbandry↗
PubMed2004

Effects of end-inspiratory and end-expiratory pressures on alveolar recruitment and derecruitment in saline-washout-induced lung injury -- a computed tomography study.

BACKGROUND: Lung protective ventilation using low end-inspiratory pressures and tidal volumes (VT) has been shown to impair alveolar recruitment and to promote derecruitment in acute lung injury. The aim of the present study was to compare the effects of two different end-inspiratory pressure levels on alveolar recruitment, alveolar derecruitment and potential overdistention at incremental levels of positive end-expiratory pressure. METHODS: Sixteen adult sheep were randomized to be ventilated with a peak inspiratory pressure of either 35 cm H2O (P35, low VT) or 45 cm H2O (P45, high VT) after saline washout-induced lung injury. Positive end-expiratory pressure (PEEP) was increased in a stepwise manner from zero (ZEEP) to 7, 14 and 21 cm of H2O in hourly intervals. Tidal volume, initially set to 12 ml kg(-1), was reduced according to the pressure limits. Computed tomographic scans during end-expiratory and end-inspiratory hold were performed along with hemodynamic and respiratory measurements at each level of PEEP. RESULTS: Tidal volumes for the two groups (P35/P45) were: 7.7 +/- 0.9/11.2 +/- 1.3 ml kg(-1) (ZEEP), 7.9 +/- 2.1/11.3 +/- 1.3 ml kg(-1) (PEEP 7 cm H2O), 8.3 +/- 2.5/11.6 +/- 1.4 ml kg(-1) (PEEP 14 cm H2O) and 6.5 +/- 1.7/11.0 +/- 1.6 ml kg(-1) (PEEP 21 cm H2O); P < 0.001 for differences between the two groups. Absolute nonaerated lung volumes during end-expiration and end-inspiration showed no difference between the two groups for given levels of PEEP, while tidal-induced changes in nonaerated lung volume (termed cyclic alveolar instability, CAI) were larger in the P45 group at low levels of PEEP. The decrease in nonaerated lung volume was significant for PEEP 14 and 21 cm H2O in both groups compared with ZEEP (P < 0.005). Over-inflated lung volumes, although small, were significantly higher in the P45 group. Significant respiratory acidosis was noted in the P35 group despite increases in the respiratory rate. CONCLUSION: Limiting peak inspiratory pressure and VT does not impair alveolar recruitment or promote derecruitment when using sufficient levels of PEEP.

Animals↗
PubMed2004

Pulmonary gas distribution during ventilation with different inspiratory flow patterns in experimental lung injury -- a computed tomography study.

BACKGROUND: There is still controversy about the optimal inspiratory flow pattern for ventilation of patients with acute lung injury. The aim of this study was to compare the effects of pressure-controlled ventilation (PCV) with a decelerating inspiratory flow with volume-controlled ventilation (VCV) with constant inspiratory flow on pulmonary gas distribution (PGD) in experimentally induced ARDS. METHODS: Sixteen adult sheep were randomized to be ventilated with PCV or VCV after surfactant depletion by repeated bronchoalveolar lavage. Positive end-expiratory pressure (PEEP) was increased in a stepwise manner from zero end-expiratory pressure (ZEEP) to 7, 14 and 21 cm H(2)O in hourly intervals. Respiratory rate, inspiration-to-expiration ratio and tidal volume were kept constant. Central hemodynamics, gas exchange and airway pressures were measured. Electron beam computed tomographic (EBCT) scans of the entire lungs were performed at baseline (preinjury) and each level of end-expiratory pressure during an inspiratory and expiratory hold maneuver. The lungs were three-dimensionally reconstructed and volumetric assessments were made separating the lungs into four subvolumes classified as overinflated, normally aerated, poorly aerated and nonaerated. RESULTS: Pressure-controlled ventilation led to a decrease in peak airway pressure and an increase in mean airway pressure. No differences between groups were found regarding plateau pressures, hemodynamics and gas exchange. Recruitment, defined as a decrease in expiratory lung volume classified as nonaerated, was similar in both groups and predominantly associated with PEEP. Overinflated lung volumes were increased with PCV. CONCLUSIONS: In this model of acute lung injury, ventilation with decelerating inspiratory flow had no beneficial effects on PGD when compared with ventilation with constant inspiratory flow, while the increase in overinflated lung volumes may raise concerns regarding potential ventilator-associated lung injury.

Animals↗
PubMed2004

Human cryptosporidiosis: an update with special emphasis on the situation in Europe.

The genus Cryptosporidium consists of different species and genotypes which infect a wide range of hosts, including humans. The parasite is ubiquitous and lack of differentiation between the species and strains has made it difficult to track down sources of human and animal infections. Genetic analysis of strains and isolates has led to the redescription of Cryptosporidium with special consideration of the host specificity and possible ways of transmission to humans. Infection with the small oocysts usually occurs directly by faecal-oral transmission, water- or food-borne. In Europe water from different sources is frequently contaminated with oocysts. Generally, humans are most frequently infected with C. hominis in an anthroponotic cycle (especially in cases of infections imported from highly endemic (sub-) tropical regions) and the animal genotype (type II) of C. parvum in a zoonotic cycle which seems to play a major role in autochthonous infections in Switzerland, the UK and probably other European countries. Other species (such as C. felis or the avian species C. meleagridis and C. baileyi) and genotypes are rare in humans and mostly restricted to immunocompromised individuals who are highly susceptible to serious opportunistic cryptosporidial infections.

Animals↗
PubMed2003

Prevalence and control of bovine cryptosporidiosis in German dairy herds.

In a 5-year survey regarding its prevalence and importance in five German state veterinary laboratories Cryptosporidium was diagnosed annually in 19-36% of faecal samples either submitted to the laboratories or taken post mortem. In approximately half of the cases no other enteropathogens were detected. However, only 73% of 30 laboratories participating in a questionnaire survey routinely tested for this parasite, and the majority of researchers considered cryptosporidiosis to be of minor importance. In a placebo-controlled field study 152 suckling calves were treated daily against cryptosporidiosis either with sulfadimidine or with halofuginone (Halocur, Intervet) over 1 week. Treatment by oral drench started at the onset of diarrhoea in the herd. Oocyst excretion, faecal consistency and health status were recorded five times for a 3-week period. Oocyst excretion peaked 7-14 days in the placebo group after the onset of diarrhoea, and during that period prevalence and intensity of excretion were significantly lower in the halofuginone-treated group compared to the sulfadimidine and the placebo control groups. The health status (diarrhoea, dehydration) declined in all groups but was significantly (P<0.05-0.001) better in the halofuginone group in the first 2 weeks. Halofuginone effectively (P<0.05-0.001) reduced oocyst excretion and improved the health status of the treated animals, while sulfadimidine had no effect against Cryptosporidium.

Animals↗
PubMed2003

Comparison of viability assays for Cryptosporidium parvum oocysts after disinfection.

In order to test various viability assays for Cryptosporidium parvum oocysts were used to infect HCT-8 cells in vitro or baby mice. Infected cells were either stained with fluorescent anti-Cryptosporidium-antibody or lysed and subjected to C. parvum-specific PCR after 48 h. Titrations with infective oocysts were performed and compared to oocysts disinfected with Neopredisan for 2 h at varying concentrations. Caecal smears and histological sections from infected animals were examined in parallel. The number of foci of parasite development in vitro after immunofluorescent staining correlated well with the infection dose. PCR was less quantifiable and the results were not always reproducible, especially when low infection doses were used. Disinfection resulted in a dose-dependent reduction of oocyst infectivity when compared to the controls in all three assays. The infection of cells cultured in vitro with oocysts of C. parvum provides a suitable tool for the estimation of viability after treatment with chemical disinfectants. Immunofluorescence is easy to perform and gives quantitative results, while PCR-based detection of parasite DNA, although possible, requires the use of more sophisticated tools for quantification.

Animals↗
PubMed2002

Fasciola hepatica alters coagulation parameters in sheep plasma in vivo and in vitro.

The blood-sucking activities of the liver fluke, Fasciola hepatica, are likely to cause alterations in coagulation during the course of infection; and the effect of F. hepatica on various coagulation parameters was studied during the course of acute and chronic fasciolosis of sheep over a period of 17 weeks. Whole blood and plasma samples from infected sheep (with 800 metacercariae each) and uninfected controls were collected weekly until 17 weeks post-infection (w.p.i.) and the activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) were determined. Additionally, adult F. hepatica were recovered from bile ducts, incubated for the production of excretory/secretory products (ESP) or homogenised and the effect of fluke products on APTT, PT and TT was determined. Anaemia was evident in infected sheep from 8 w.p.i. until 17 w.p.i. Plasma APTT was accelerated during 8, 9, 12, 14, 16 and 17 w.p.i., while PT was prolonged at 8-11 w.p.i. and TT at 10, 14 and 17 w.p.i. Addition of worm ESP or homogenate to plasma resulted in an enhancement of the intrinsic pathway (APTT) together with a prolongation of the extrinsic and common pathways (PT, TT) of coagulation. It was concluded that F. hepatica contains and releases substances that may contribute to coagulation changes in vivo. Further characterisation of the active substance(s) in vitro revealed heat inactivation, a size >30 kDa and inhibition by the proteinase inhibitors Complete and EDTA for the APTT-accelerating substance(s). The TT-deceleration, in contrast, was increased after heating.

Animals↗
PubMed2002

Variation in clinical and parasitological traits in Pietrain and Meishan pigs infected with Sarcocystis miescheriana.

Future prophylaxis needs new concepts, including natural disease resistance of hosts against infectious agents. Genomic approaches to detect and improve disease resistance in farm animals and the molecular mechanisms involved in host-parasite interactions depend to a high degree on the trait differences between founder breeds, i.e. on the animal model. The present study evaluates differences in susceptibility/resistance against Sarcocystis miescheriana in the European Pietrain (PI) and the Chinese Meishan (ME) pig breeds, based on 25 individuals, infected orally with 5x10(4) sporocysts of S. miescheriana. Significant differences appeared in clinical, serological, haematological and parasitological findings. The major discriminating period post infection (p.i.) was between days 42 and 45. Severity of signs was negatively correlated with specific immunoglobulin titres during the first 3 weeks p.i. and positively with the load of bradyzoites in muscle tissues of the pigs. Loads of bradyzoites in muscle tissues were 20 times higher in PI than in ME. Sarcocystis-specific differences between the two breeds were in the range of 1-2 standard deviations. The study lays the foundation for further experiments to analyse chromosomal regions, candidate genes, and thus the molecular basis of Sarcocystis susceptibility/resistance as a model for host-parasite interaction in protozoan infectious disease.

Animals↗
PubMed2002

The role of Isospora suis as a pathogen in conventional piglet production in Germany.

In order to evaluate the prevalence of Isospora suis in conventional piglet production in Germany, pooled faecal samples from 327 pig litters from 18 pig production units (20-320 sows each) were examined. At least 10 litters from each farm were investigated. I. suis was present on 83% of the farms and 42.5% of the litters, the infection rate being highest in the third week of age (48.2%). I. suis was found more frequently in samples of diarrhoea than in firm faeces (49.2% compared to 22.2%). Twenty naturally infected piglets from six of these farms underwent examination post mortem, including histology, virology and bacteriology. Histological examination revealed atrophy of the villi in various degrees, mild crypt hyperplasia, fusion of the villi, metaplastic epithelium, erosions and necrosis, especially in the medium and the posterior jejunum and in the ileum. Asexual and sexual developmental stages of the parasite were found in varying numbers in the epithelium of the whole of the small intestine. Bacteria and viruses were mostly excluded as the cause of diarrhoea, and it was concluded that I. suis was the primary pathogen inducing distinct changes and clinical symptoms of diarrhoea.

Animal Husbandry↗
PubMed2001

Occurrence of helminths in pig fattening units with different management systems in Northern Germany.

The helminth infections on 13 pig fattening farms with different management systems (complete or partial all-in-all-out system or continuous fattening) in North-Western Germany were investigated over at least three fattening periods. Pooled faecal samples were taken from pens once before and three times after anthelmintic treatment. At the beginning of fattening 34.9% of the samples contained helminth eggs, mainly from Oesophagostomum spp. (27.5%). Ascaris suum eggs were found in 10.5% of the samples, while other parasites were only rarely found. The number of pig-supplying farms was positively correlated with the helminth infection prevalence. Immediately after deworming, all pen samples were free of helminth eggs. However, the prevalences increased again, and by the end of fattening A. suum was found in 33.0% and strongylids in 6.0% of the samples. Pens harbouring A. suum-excreting pigs at the beginning of fattening had higher infection levels at the end, and this was also the case for nodular worms. The final prevalence of Ascaris was higher in partial exchange systems than in complete all-in-all-out systems and in old pig houses compared to new ones. Transmission of both Ascaris and Oesophagostomum was highest in autumn and winter. Thus, a single anthelmintic treatment at the beginning of fattening could not prevent infection during fattening, and the state of infection at the beginning was associated with the helminth burden at slaughter. Therefore, the purchase of parasite-free pigs in combination with appropriate hygiene management may minimise the initial infection pressure and keep subsequent infection of the herd at a minimum.

Animal Husbandry↗