The occurrence of Echinococcus multilocularis in red foxes in lower Saxony: identification of a high risk area by spatial epidemiological cluster analysis

There is considerable interest in the spatial distribution of Echinococcus multilocularis in red foxes (Vulpes vulpes L.), because this parasite causes the zoonoses of alveolar echinococcosis which is potentially of high fatality rate. High risk areas are known from France, Switzerland and the Swabian Alb in Germany for a long time. In this work, the spatial scan statistic is introduced as an instrument for identification and localisation of high risk areas, so called disease clusters in spatial epidemiology. The use of the spatial scan statistic along with data about the distribution of the parasite in 5365 red foxes in Lower Saxony, that were collected during 1991 to 1997, led to the identification of another high risk area. The relative risk for this disease cluster is approximated by RR = 5.03 (CI0.95(RR) = [4.27; 6.58]) for the period of 1991 to 1994 and by RR = 4.45 (CI0.95(RR) = [3.53; 5.59]) for the period of 1994 to 1997, respectively.     

Effects on functions of ovine blood mononuclear cells for each of several fatty acids at concentrations found in plasma of healthy and ketotic ewes

OBJECTIVE: To assess effects on functions of peripheral blood mononuclear cells (PBMC) obtained from ewes for each of several fatty acids represented in ovine plasma at concentrations mimicking those of ketotic or healthy ewes. SAMPLE POPULATION: Blood samples obtained from 6 Sardinian ewes. PROCEDURE: The PBMC were cultured in media that contained oleic (OA), palmitic (PA), stearic (SA), linoleic (LA), or palmitoleic (POA) acid at concentrations similar to those of ketotic or healthy ewes. Synthesis of DNA was stimulated by use of concanavalin A or pokeweed mitogen (PWM). Secretion of IgM was stimulated by use of PWM. RESULTS: High concentrations (900, 450, and 225 micromol/L) of OA significantly inhibited DNA synthesis and IgM secretion of PBMC. Conversely, low concentrations (56 or 28 micromol/L) of OA significantly enhanced DNA synthesis of PBMC. High concentrations of PA (600, 300, 150, 75, 375, or 18.7 micromol/L) and SA (300, 150, or 75 micromol/L) significantly inhibited DNA synthesis of PBMC. High concentrations of PA (600, 300, 150, 75, 375, or 18.7 micromol/L) and SA (300, 150, 75, or 38 micromol/L) also significantly inhibited IgM secretion of PBMC. None of the concentrations of LA and POA affected PBMC functions. CONCLUSION AND CLINICAL RELEVANCE: Impaired immunoresponsiveness of ketotic ewes is likely associated with an increase of plasma concentrations of OA, PA, or SA and not with that of LA or POA. At physiologic concentrations, single fatty acids are likely to participate in modulation of immunoresponsiveness by exerting suppressive or stimulatory effects on immune cells.     

Evaluation of the perioperative stress response in dogs administered medetomidine or acepromazine as part of the preanesthetic medication

OBJECTIVE: To compare the perioperative stress response in dogs administered medetomidine or acepromazine as part of the preanesthetic medication. ANIMALS: 42 client-owned dogs that underwent elective ovariohysterectomy. PROCEDURE: Each dog was randomly allocated to receive medetomidine and butorphanol tartrate (20 microgram/kg and 0.2 mg/kg, respectively, IM) or acepromazine maleate and butorphanol (0.05 and 0.2 mg/kg, respectively, IM) for preanesthetic medication. Approximately 80 minutes later, anesthesia was induced by administration of propofol and maintained by use of isoflurane in oxygen. Each dog was also given carprofen before surgery and buprenorphine after surgery. Plasma concentrations of epinephrine, norepinephrine, cortisol, and beta-endorphin were measured at various stages during the perioperative period. In addition, cardiovascular and clinical variables were monitored. RESULTS: Concentrations of epinephrine, norepinephrine, and cortisol were significantly lower for dogs administered medetomidine. Concentrations of beta-endorphin did not differ between the 2 groups. Heart rate was significantly lower and mean arterial blood pressure significantly higher in dogs administered medetomidine, compared with values for dogs administered acepromazine. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that for preanesthetic medications, medetomidine may offer some advantages over acepromazine with respect to the ability to decrease perioperative concentrations of stress-related hormones. In particular, the ability to provide stable plasma catecholamine concentrations may help to attenuate perioperative activation of the sympathetic nervous system.     

Analgesic effect of meloxicam in canine acute dermatitis--a pilot study

A double-blind trial was performed on 12 client-owned dogs suffering from acute and painful dermatitis. Clinically these cases represented pyotraumatic dermatitis and pyotraumatic folliculitis. Six dogs were injected with meloxicam and 6 were given placebo. Signs of pain were recorded on a visual analogue scale before administering the drug. This was repeated over the following 2-3 days. All dogs were treated with cephalexin orally. Six dogs given meloxicam and cephalexin showed an average decrease of pain on day 2 of 28.3%, whereas the 6 dogs given placebo and cephalexin showed an average decrease of pain on day 2 of 8.3%. When compared in the Wilcoxon two-sample test, using change in percent and absolute change, the 2 groups yielded p = 0.026 and p = 0.064 respectively. These findings indicate that meloxicam has an analgesic effect on acute dermatitis in dogs.     

Factors involved in the early pathogenesis of bovine Staphylococcus aureus mastitis with emphasis on bacterial adhesion and invasion. A review

Staphylococcus aureus is the most important and prevalent contagious mammary pathogen; it causes clinical and subclinical intramammary infection with serious economic loss and herd management problems in dairy cows. In vitro studies have shown that Staphylococcus aureus adheres to mammary epithelial cells and extracellular matrix components and invades into mammary epithelial as well as other mammary cells. Staphylococcus aureus strains from intramammary infection produce several cell surface-associated and extracellular secretory products. The exact pathogenic roles of most of the products and their effects on adhesion and invasion are not well evaluated. It is also known that mammary epithelial cell-associated molecules and extracellular matrix components interact with S. aureus during the pathogenesis of mastitis, but their roles on adhesion and invasion have not been characterized. The adhesion of S. aureus to epithelial cells may involve non-specific physicochemical interactions and/or specific interactions between bacterial cell-associated ligands and host cell surface receptors. In vitro adhesion depends on the S. aureus strain, the growth phase of the bacteria, the growth medium and the origin of the epithelial cells. Adhesion is hypothesized to be a prerequisite and crucial early step for mammary gland infection. Staphylococcus aureus invades mammary epithelial cells. It also invades other cells such as endothelial cells and fibroblasts. Bacteria are found enclosed in membrane bound vacuoles in the cytoplasm of mammary epithelial cells. Recent observations indicate that S. aureus escapes from the phagosome into the cytoplasm and induces apoptosis. The invasion into mammary epithelial cells may occur through an endocytic process that requires involvement of elements of the cytoskeleton or by direct binding of bacteria to epithelial cells through a process mediated by specific receptors that needs de novo protein synthesis by both cells. Thus, the recurrent subclinical infection may result from this intracellular existence of bacteria that are protected from host defenses and effects of antibiotics. This review emphasizes on recent findings on S. aureus adhesion to mammary epithelial cells and extracellular matrix components and invasion into mammary epithelial cells.     

Bovine herpesvirus-1 (BHV-1) recombinant expressing pseudorabies virus (PrV) glycoproteins B and C induces type 1 immune response in BALB/c mice

Bovine herpesvirus 1 (BHV-1) attached poorly and penetrated into a mouse cell line, BALB 3T3/A31, but a recombinant BHV-1/TF7-6, which expresses pseudorabies virus (PrV) gB and gC genes, did attach and penetrated into cells more efficiently. In this study the gene green fluorescent protein (GFP) has been integrated into genome of BHV-1/TF7-6 and its parental line of BHV-1. When the mouse mesenteries were incubated in vitro and infected with BHV-1/TF7-6/GFP, strong fluorescence was observed while BHV-1/GFP infection hardly demonstrated fluorescence, suggesting that BHV-1 recombinant expressing PrV gB and gC can infect mouse tissue cells more efficiently than the parental BHV-1 does. When BALB/c mice were inoculated with purified BHV-1/TF7-6 or its parental BHV-1, the former induced lower level of anti-BHV-1 immunoglobulin G (IgG) than the latter did. When sub-classes of anti-BHV-1 IgG were analyzed, it was found that mice immunized with BHV-1/TF7-6 or the parental BHV-1 demonstrated the same level of IgG2a. Since anti-BHV-1 IgG1 level was lower in mice inoculated with BHV-1/TF7-6, the IgG2a:IgG1 ratio was higher in BHV-1/TF7-6 inoculated mice than in the parental BHV-1 inoculated ones. These results indicate that BHV-1/TF7-6 induces type 1 predominant immune to BALB/c mice.     

Early hepatic immune response in rats infected with Fasciola hepatica

We investigated the phenotype of the T cells (CD4+ and CD8+) that produced Th1 (IFN-gamma) and Th2 cytokines (IL-4 and IL-10) during the firsttwo weeks of experimental fasciolosis in rats. We also followed the kinetics of the cytokine and proliferative responses of hepatic mononuclear cells (HMNC) over the same period. We found that HMNC were more numerous in the infected animals than in the controls. The percentage of CD4+ cells increased significantly after infection, whereas the percentage of CD8+ cells did not change. Moreover, the frequency of the cells producing (CP) cytokine changed after infection. The frequency of CP IFN-gamma on 7 days postinfection (pi) was similar to that in control animals. However, the frequency of CP IFN-gamma was clearly lower on day 14 pi, whereas the frequency of CP IL-4 and CP IL-10 had increased. The CP IL-10-were mostly CD4+. Mitogenic stimulation (phorbol myristate acetate/ionomycin) of HMNC led to an increase in the amounts of the Th2 cytokines in the supernatant on days 7 and 14 pi, with the increase more pronounced on day 14. In contrast, IFN-gamma levels also increased by day 7 pi but then decreased to below control levels by day 14. In addition, HMNC proliferation in response to mitogen followed a similar pattern to IFN-gamma production. These findings suggested that, during the first 2 weeks of infection, F hepatica induced a transient ThO cytokine profile followed by downregulation of the cellular response and the induction of a Th2 cytokine profile.     

Evaluation of the hepatic NK cell response during the early phase of Fasciola hepatica infection in rats

The in situ distribution of NK cells in rat liver during the first 28 days of an experimental infection with F hepatica was investigated. NK cells were distributed homogeneously throughout the hepatic parenchyma in uninfected animals. The total number of hepatic mononuclear cells increased significantly following infection, but the proportion of NK cells did not change. After infection, these cells were found around the portal space, around the centrolobular vein, in the periportal fibrosis and in the band of collagen. However, no NK cells could be detected in or around the granuloma during infection. The frequency of both I L-2- and IFNgamma-producing NK cells was higher on day 7 postinfection (pi) but only the percentage of IFNgamma -CD161+ subsets remained elevated thereafter, whereas the percentage of both IL-2+CD161+ and IL-4+CD161+ subsets returned to the baseline. The number of CD161+IL10+ cells did not change significantly. These results suggest that NK cells could be another source for the early production of IFNgamma but provide no evidence that these cells are involved in early events associated with granuloma formation.     

An outbreak of enzootic bovine leukosis in upper Egypt: clinical,laboratory and molecular-epidemiological studies

In 1989, 220 Holstein Friesian cattle (212 heifers and eight bulls) were imported from Minnesota, USA, to form a closed dairy herd in Arab El-Aoumar, Assiut, Upper Egypt. In November 1996, some abnormal signs such as loss of weight, decreased milk yield, external lymphadenopathy and decreased appetite were observed on this farm. Serological screening by enzyme-linked immunosorbent assay revealed a seroprevalence of antibodies directed against bovine leukaemia virus (BLV) of 37.7% in cattle under 2 years old and of 72.8% in animals more than 2 years old. Diagnosis was confirmed by the detection of BLV proviral DNA using polymerase chain reaction with primers amplifying a fragment of the env gene. Out of 21 tested leucocyte fractions from individual animals, 15 were positive showing a BLV-specific amplicon of 444 base pairs. Analysis of the amplicons for restriction fragment length polymorphisms and DNA sequencing results allowed the isolates to be typed. Since this was the first recorded case of enzootic bovine leukosis in Upper Egypt, strict quarantine measures were adopted and all serologically positive animals in the herd were culled.