A cross sectional study of the prevalence and intensity of Balantidium coli in pigs was carried out on a Danish research farm. The prevalence of B. coli infection increased from 57% in suckling piglets to 100% in most pig groups > or = 4 weeks old. The mean number of cysts per gram faeces (CPG) of pigs aged 12 weeks and younger were 52 weeks had significantly higher counts of > or = 865 CPG. Although some lactating sows had very high CPG's, no significant differences in CPG could be detected between the intensities of pregnant sows, lactating sows and empty and dry sows. No human cases of B. coli infection have been published in Denmark though it is zoonotic.
Trimellitic anhydride (TMA) is a cause of asthma in man. Dose-dependent TMA-specific IgE, histopathology, and airway responses after sensitization by inhalation were examined in the Brown Norway rat. Rats were exposed to 0.04, 0.4, 4, or 40 mg/m3 TMA aerosol for 10 min, once a week, over 10 weeks. All lower exposures were, subsequently, rechallenged to 40 mg/m3 TMA aerosol. All rats received a sham exposure 1 week prior to the first TMA exposure. Following the sham exposure and weekly after each TMA exposure, TMA-specific IgE and both early-phase airway response (EAR) and late-phase airway response (LAR) were measured using enhanced pause (Penh). All rats sensitized by 40 mg/m3 TMA developed specific IgE, EAR, and LAR to one or more of the challenges to 40 mg/m3 TMA. TMA of 4 mg/m3 induced a much lower, but stable, specific IgE response. EAR and LAR were observed only after a 40 mg/m3 TMA rechallenge in this group, but it was much larger than that observed in the 40 mg/m3 TMA-sensitized and challenged group. Exposure-dependent histopathological changes noted included eosinophilic granulomatous interstitial pneumonia, perivascular eosinophil infiltrates, bronchial-associated lymphoid tissue hyperplasia, and peribronchiolar plasma cell infiltrates.
An experimental rat model to study acute cytomegalovirus infections is described. Eight-week old male Brown Norway rats, immunosuppressed by total body irradiation, were infected with rat cytomegalovirus (RCMV). The effects of infection were determined by survival rates and the presence of virus or viral components in different organs was assayed by plaque test, immunoperoxidase staining, dot-blot DNA hybridization and in situ DNA hybridization. At days 10-post infection nearly 90% of the animals had died. Spleen, liver and bone marrow were heavily infected. Interstitial pneumonia was observed. Pathological findings strongly resembled the full scale of lesions in human CMV infections. Anti-RCMV hyperimmune serum was effective against mortality from RCMV infection and viral spread to lungs and liver was prevented. This model is appropriate for studies on the pathogenesis and antiviral therapy of CMV infections in the immunocompromised host.
Despite of the fact that engine manufacturers develop a new technology to reduce exhaust emissions, insufficient attention given to particulate emissions. However, diesel exhaust particles are a major source of air-borne pollution, contain vast amount of polycyclic aromatic hydrocarbons (PAHs) and may have deleterious effects on the immune system, resulting in the induction and enhancement of pro-allergic processes. In the current study, vehicle emitted particles (VEP) from 2 different types of cars (diesel - D and gasoline - G) and locomotive (L) were collected. Overall, 129 four-week-old, male SPF-class Kunming mice were subcutaneously instilled with either low dose 100, 250 or high dose, 500mg/kg VEP and 15 mice were assigned as control group. The systemic toxicity was evaluated and alterations in the percentages of the CD3, CD4, CD8, CD16, CD25 expressing cells, basophils, eosinophils and neutrophils were determined. Basophil percentages were inversely associated with the PAH content of the VEPs, however basophil sensitization was more important than cell count in VEP exposure. Thus, the effects of VEP-PAHs emerge with the activation of basophils in an allergen independent fashion. Despite the increased percentage of CD4+ T cells, a sharp decrease in basophil counts at 500mg/kg of VEP indicates a decreased inhibitory effect of CD16+ monocytes on the proliferation of CD4+ T cell and suppressed polarization into a Th2 phenotype. Therefore, although the restrictions for vehicles emissions differ between countries, follow up studies and strict regulations are needed.
Prolonged exposure to allergen has been proposed to be important for the development of bronchial hyperresponsiveness and airway remodelling in asthma. The present study was designed to examine the effect of chronic allergen exposure on bronchial responsiveness, eosinophil infiltration, and airway remodelling. We sensitized brown Norway rats with the occupational allergen trimellitic anhydride (TMA) and exposed the animals to TMA conjugated to rat serum albumin (TMA-RSA) on 5 consecutive days each week for 9 weeks, starting 4 weeks after sensitization. IgE and IgG anti-TMA antibodies in serum and bronchial responsiveness to acetylcholine were evaluated before and at weeks 3, 6, and 9 of allergen exposure. Thickness of the airway wall, airway luminal narrowing, and the number of goblet cells and eosinophils in the airway wall were evaluated with an image analysis system in lungs resected after the last assessment of bronchial responsiveness, at the end of the 9-week allergen exposure. All rats developed IgE and IgG anti-TMA antibodies after sensitization. The levels of antibodies increased with allergen exposure until week 6, and then declined. Bronchial hyperresponsiveness to acetylcholine was induced in allergen-exposed rats without ongoing airway eosinophilia. Bronchial hyperresponsiveness induced by chronic allergen exposure via inhalation was accompanied by significantly increased thickness of smooth muscle and airway narrowing in the small airways, and goblet cell hyperplasia in the large airways. We conclude that chronic exposure to allergen can induce bronchial hyperresponsiveness and airway wall remodelling. Airway wall remodelling may contribute to bronchial hyperresponsiveness.
Control and eradication of porcine reproductive and respiratory syndrome virus type 2 using a modified-live type 2 vaccine in combination with a load, close, homogenise model: an area elimination study.
Porcine reproductive and respiratory syndrome virus (PRRSV) causes significant animal and economic losses worldwide. The infection is difficult to control and PRRSV elimination at local level requires coordinated intervention among multiple farms. This case study describes a successful elimination of PRRSV from all 12 herds on the Horne Peninsula, Denmark, using a combination of load, close, homogenise (LCH) using PRRSV type 2 modified-live vaccine, optimised pig flow, and'10 Golden Rules' (10GR) for biosecurity management. To the authors' knowledge, this is the first successful European PRRSV area elimination project documented in detail. The PRRSV type 2 modified-live vaccine was used as part of the LCH method in breeding herds. Complete or partial depopulation was performed in some infected herds. A simplified biosecurity protocol (10GR) based on the McREBEL™ system of pig flow management, was employed in all herds and at all times throughout the study.
At study commencement, all herds were infected with PRRSV, and most were actively shedding virus. In just over 18 months, all 12 herds on the Horne Peninsula were confirmed to be PRRSV negative by polymerase chain reaction testing and negative for antibodies against PRRSV by enzyme-linked immunosorbent assay testing. All herds were subsequently obtained 'Specific Pathogen Free' status for PRRSV.
This study provides compelling evidence suggesting that an area elimination plan combining LCH with PRRSV type 2 vaccination, optimised pig flow, and 10GR for biosecurity management can effectively eliminate PRRSV from a geographic area. Additionally this study confirms the value of a previously unpublished, simplified alternative to the McREBEL system for controlling PRRSV.
We examined the effects of different immunomodulators administered topically on asthmatic responses in a rat model of asthma. Sensitised Brown-Norway rats were administered rapamycin, SAR943 (32-deoxorapamycin), IMM125 (a hydroxyethyl derivative of D-serine(8)-cyclosporine), and budesonide by intratracheal instillation 1 h prior to allergen challenge. Allergen exposure induced bronchial hyperresponsiveness, accumulation of inflammatory cells in bronchoalveolar lavage fluid, and also an increase in eosinophils and CD2+, CD4+ and CD8+ T cells in the airways. Interleukin-2, interleukin-4, interleukin-5, interleukin-10, and interferon-gamma mRNA expression was upregulated by allergen exposure. Budesonide abolished airway inflammation, suppressed the mRNA expression for interleukin-2, interleukin-4, and interleukin-5 (P
OBJECTIVE: To investigate whether DL-alpha-lipoic acid (LA) can offer lenticular protection in diabetic rats. METHOD: 36 Brown-Norway (BN) specific pathogen free (SPF) rats (7 week-old, female), were divided into 3 groups comprising of the diabetes mellitus (DM) group (14 rats), the diabetes mellitus treated with LA (DM + LA) group (14 rats), and the control (CTL) group (8 rats). The diabetic cataract was induced by streptozotocin (STZ) injection. Powdered food mixed with 0.3% LA was given to the DM + LA group, 3 days after STZ injection. Lens density was measured with EAS-1000, blood glucose and lens glutathione concentration was examined. RESULT: 2 weeks after STZ injection, there was a subcapsular reticular opacity in the DM; Lens opacity became more severe and enlarged with increased duration of STZ exposure. 4 weeks later, there was slight lens opacity in the DM + LA group. After 5 weeks, there were significant differences in lens densities between the DM and the DM + LA groups (P 0.05); At 80 days, the concentration of blood glucose in the DM + LA was less than that of in the DM (P 0.05). CONCLUSION: LA ingested orally can effectively reduce STZ-induced blood glucose and inhibit diabetic cataractogenesis in rats.
The combined effect of 9-(1,3-dihydroxy-2-propoxymethyl)guanine (DHPG, ganciclovir) and hyper immune serum (HIS) was studied in two different rat models. In the first model, a lethal generalized rat cytomegalovirus (RCMV) infection was established in immunosuppressed Brown Norway (BN) rats. Treatment with DHPG or hyper immune serum (HIS) effectively reduced both mortality rate and virus titers in the liver and lungs. By combined treatment the effective dose of both DHPG and HIS was reduced to 25%. The fractionary effective dose was 0.5, indicating a moderate synergistic effect on survival. Combined treatment also established a significant reduction of virus titers in lungs and liver (P
In Denmark, a porcine reproductive and respiratory syndrome virus (PRRSV) control programme, comprising vaccination of seropositive herds with a live American type PRRSV vaccine, was started in 1996. In several of these herds, spread of vaccine virus from vaccinated 3-18 week old pigs to non-vaccinated sows was demonstrated by the isolation of vaccine virus from fetuses and stillborn piglets. Surprisingly, sows infected with the American type vaccine strain consistently exhibited significantly stronger serological responses towards European type PRRSV than American type PRRSV. In order to elucidate whether the unexpectedly strong serological reaction towards European-type PRRSV in American type PRRSV infected sows was due to a booster reaction, or reactivation of an unrecognized, latent infection in the sows with European type PRRSV, a challenge study with the vaccine was carried out. In this study, the stronger serological response towards European type PRRSV than towards American type PRRSV was reproduced, and reactivation of the previous natural infection with European PRRSV could neither be demonstrated by virus isolation nor by RT-PCR. So, the increase in antibody titers towards European PRRSV in previously European PRRSV infected pigs after challenge with the vaccine strain seems to be the result of a boosting effect on the immune system, induced by the heterologous vaccine PRRSV strain.