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.     

Veterinary aspects of alveolar echinococcosis--a zoonosis of public health significance

Human alveolar echinococcosis (AE), caused by the metacestode stage of Echinococcus multilocularis, is a serious zoonosis which caused up to 100% lethality in untreated patients before the 1970s, when modern methods of treatment were not yet established. AE occurs in large areas of the northern hemisphere mostly with low country-wide prevalences, but high prevalences of up to 4% have been reported from small population groups in highly endemic foci, e.g. from China. AE includes many veterinary aspects which are the topic of this review. Recent studies have shown that E. multilocularis has a wider geographic range than previously anticipated. There is evidence for growing populations of red foxes (Vulpes vulpes) in some areas, for increasing invasion of cities by foxes and also for establishment of the parasite cycle in urban areas. These and other factors may lead to an increased infection risk for humans. Significant progress has been made in the development of sensitive and specific new techniques for the intra vitam and post mortem diagnosis of intestinal E. multilocularis infection in definitive hosts, notably the detection of coproantigen by enzyme-linked immunosorbent assay and of copro-DNA by PCR. Both tests can also be used for the identification of E. multilocularis in faecal samples collected in the environment. Recommendations are given for chemotherapy and chemoprophylaxis of the intestinal infection in definitive hosts. In recent years, infections with the metacestode stage of E. multilocularis have not only been diagnosed in humans in several regions, including at least eight countries in central Europe, but also in animal species which do not play a role in the transmission cycle (wild and domestic pigs, dogs etc.). From 1987 to 2000 our group in Zurich has diagnosed 10 cases of AE in dogs and 15 in captive monkeys. In 2 dogs, concurrent infections of the intestine and of the liver with adult and larval stages of E. multilocularis, respectively, were observed for the first time. Clinical data are presented, and methods of diagnosis and treatment (surgery, chemotherapy) are described. Furthermore, small liver lesions caused by E. multilocularis were diagnosed in 10% of 90 slaughter pigs, and 2.9% of 522 breeding sows had specific serum antibodies against parasite antigens. In view of the unpredictable epidemiological situation, all possible measures for preventing E. multilocularis infections in humans and in domestic animals should be initiated by the veterinary and health authorities.     

Teaching of undergraduate veterinary parasitology in some European countries

A review revealed that at 20 veterinary faculties in European countries parasitology is represented in the curriculum of veterinary medicine with an average of 105 core contact hours, devoted to lectures (58%) and practicals (42%). However, there is a high diversity between faculties with ranges of total contact hours between 48 and 156. Three faculties are close to the minimum of 70 core contact hours recommended by WAAVP (2002), and one faculty is below this limit. In one of the faculties parasitology is completely integrated into interdisciplinary teaching activities, in some others there are developments in this direction which include the risk of dissolving parasitology as a discipline. One faculty with a high degree of integrated teaching has already abolished the parasitological examination. Parasitology is preferentially taught in the years three, four and five of the curriculum, but there is great variation between the faculties. Most teachers in the faculties are veterinarians. In many faculties the large numbers of students and the unsatisfactory academic teaching staff:student ratio represent a significant problem. This problem may increase with more teaching obligations caused by new curricula. Due to the high diversity in content and structure of teaching curricula of veterinary medicine between veterinary faculties in Europe international and even national exchange of students is inhibited. Therefore, and for many other reasons more activities should be initiated towards harmonisation of the study curricula in Europe.     

Experimental infection of calves and sheep with bovine Giardia isolates

9 Giardia-free calves were artificially infected with 1.5-5.1 x 10(6) Giardia cysts originating from Swiss cattle ("bovine isolates"). In 4 of these animals the course of infection was examined. After prepatent periods of 7-8 days all calves excreted high numbers of Giardia cysts for 60-112 days. During patency on 44% of the examination days Giardia cysts and antigen could be detected simultaneously in faecal samples using the flotation method and a sandwich-ELISA, respectively. With the exception of light diarrhoea lasting only for some days at the beginning of patency no other symptoms occurred. Further 5 artificially infected calves were submitted to autopsy. Giardia trophozoites were detected in 4 calves in the jejunum and in 1 animal in the ileum (peroxidase-antiperoxidase method). All animals were simultaneously infected with Campylobacter spp. and/or Rota- and Corona-virus. Electronmicroscopically mucosal attachment sites of Giardia trophozoites had intact microvilli and enterocytes. In various parts of the intestine blunting and flattening of the villi and cellular infiltrations of the mucosa were present. These alterations in calves are generally associated with bacterial and/or viral infections of calves. A Swiss bovine Giardia cyst-isolate was transmitted to 4 Giardia-free conventionally maintained lambs which excreted Giardia cysts after prepatent periods of 10-21 days for 31-61 days.     

Analgesic effect of pre-operative etodolac and butorphanol administration in dogs undergoing ovariohysterectomy

The analgesic, bleeding, and renal effects of dogs pre‐medicated with etodolac with and without butorphanol were evaluated. Twenty‐four 1‐year‐old healthy dogs, weighing 19 ± 3 kg (mean ± SD) were randomly assigned to four treatment groups (n = 6): control (C), etodolac (E), butorphanol (B), and etodolac with butorphanol (EB). Etodolac (12–14 mg kg^?1 PO) was given 1 hour before propofol induction and isoflurane maintenance anesthesia. Butorphanol (0.4 mg kg^?1 IV) was given immediately following endotracheal intubation. Control dogs received only propofol (8 mg kg^?1 to effect) and isoflurane anesthesia. All dogs were mechanically ventilated to maintain Pe ′CO₂ between 35 and 45 mm Hg (4.7–6.0 kPa). Lactated Ringer's solution was given at 10 mL kg^?1 hour^?1 during anesthesia. Plasma cortisol concentrations were assessed 1 day prior to surgery (baseline), immediately prior to anesthesia induction, and every 30 minutes until 5 hours following extubation, and 1 day after surgery. Total duration of anesthesia was 50 minutes and total surgery duration was 30 minutes. Isoflurane concentration area under the curve (AUC) over time during the anesthesia was compared among treatment groups. Buccal mucosal bleeding time (BMBT) was assessed 1 day before E administration and during surgery. Urine GGT to urine creatinine ratio, BUN, and plasma creatinine were taken daily from 1 day before to 3 days after surgery. Behavioral pain scores (numerical rating scale) were assessed by two observers blinded to the treatment during the 5‐hour recovery period at 30 minute intervals until 3 hours, and again at 5 hours after extubation. All data were analyzed using anova . Multiple comparisons were performed if the anova was significant. Alpha value was set at 0.05. Plasma cortisol concentrations significantly increased from time of extubation in all the treatment groups. They did not return to the baseline until 5, 2.5, 1.5, and 1.5 hours after extubation in the C, B, E, and EB groups, respectively. Isoflurane AUC was not significantly different among treatment groups. Dogs treated with EB had significantly less behavioral pain than all other groups throughout the 5‐hour recovery period. No significant difference was found between treatment groups or within treatment groups over time in BMBT, or any renal variables. This study demonstrated that (i) pre‐operative administration of E provides profound analgesia during the post‐operative period without renal or bleeding side‐effects in dogs undergoing OHE; and (ii) a combination of butorphanol–etodolac provides the best analgesic effect during the post‐operative period based on the behavioral pain score.