Strongyle faecal egg counts in Swiss horses: A retrospective analysis after the introduction of a selective treatment strategy

The standard parasite management of horses based on regular anthelmintic treatments, now practiced for decades has resulted in a worrying expansion of resistant helminth populations, which may considerably impair control on the farm level. The aim of the present study was to obtain a retrospective (year 2010 - 2016) nationwide analysis of faecal egg count (FEC) data from the Swiss adult horse population, related to horse age and geographic region. Thirteen labs provided a total of 16,387 FEC data of horses aged four to 39 years (average: 13.6 years). The annual number of performed FEC tests increased from 38 to 4,939 within the observation period. Independent of the annual sample size the yearly patterns of the FEC were very similar. Seventy-eight percent (n = 12,840) of the samples were negative and 90 % (n = 14,720) showed a FEC below 200 strongyle eggs per gram (EPG) of faeces. The annual mean strongyle FEC ranged between 60 and 88 EPG with a total mean of 75 EPG. Horses aged 4-7 years showed a significantly (p < 0.00001) higher mean FEC compared with the other age groups, differences were not significant among the older horses. Based on ZIP codes, samples were allocated by 70.0 %, 6.0 % and 0.2 % to the German-, French- and Italian-speaking regions of Switzerland, respectively. With 222 EPG the mean FEC in the French part of Switzerland was significantly higher (p < 0.05) than in the German-speaking region (60 EPG). Eggs of Parascaris spp., anoplocephalids and Strongyloides westeri were found in 0.36 %, 0.32 % and 0.01 % of the samples, respectively. Based on 3,813 questionnaire feedbacks from owners in 2017 covering a total of 12,689 horses, sixty-eight percent (n = 8,476) were dewormed without diagnosis, two percent (n = 240) were not dewormed at all, whereas for 30 % (n = 3,721) the selective anthelmintic treatment (SAT) concept was applied. The SAT implementation rate differed significantly (p < 0.0005) between regions, with 33 %, 20 % and 25 % for the German-, French- and Italian-speaking areas, respectively. The rate of horses spending 16-24 h on pasture per day was significantly higher in the French-speaking region compared to the German-speaking part of Switzerland (p < 0.0001). In addition, pasture hygiene was practiced at a significantly lower rate in the French-speaking part compared to the German- and Italian-speaking regions (both p < 0.0001). Overall, the shift towards the SAT-concept represents a very promising development with respect to mitigating the further spread of anthelmintic resistance.

Molecular signature of CD34+ hematopoietic stem and progenitor cells of patients with CML in chronic phase

In this study, we provide a molecular signature of highly enriched CD34+ cells from bone marrow of untreated patients with chronic myelogenous leukemia (CML) in chronic phase in comparison with normal CD34+ cells using microarrays covering 8746 genes. Expression data reflected several BCR-ABL-induced effects in primary CML progenitors, such as transcriptional activation of the classical mitogen-activated protein kinase pathway and the phosphoinositide-3 kinase/AKT pathway as well as downregulation of the proapoptotic gene IRF8. Moreover, novel transcriptional changes in comparison with normal CD34+ cells were identified. These include upregulation of genes involved in the transforming growth factorbeta pathway, fetal hemoglobin genes, leptin receptor, sorcin, tissue inhibitor of metalloproteinase 1, the neuroepithelial cell transforming gene 1 and downregulation of selenoprotein P. Additionally, genes associated with early hematopoietic stem cells (HSC) and leukemogenesis such as HoxA9 and MEIS1 were transcriptionally activated. Differential expression of differentiation-associated genes suggested an altered composition of the CD34+ cell population in CML. This was confirmed by subset analyses of chronic phase CML CD34+ cells showing an increase of the proportion of megakaryocyte-erythroid progenitors, whereas the proportion of HSC and granulocyte-macrophage progenitors was decreased in CML. In conclusion, our results give novel insights into the biology of CML and could provide the basis for identification of new therapeutic targets.

A phase II study for selection of clinical and molecular predictors for survival in patients (pts) with advanced NSCLC treated with erlotinib

17066

Background: The primary objective of the ongoing phase II study was to find clinical and molecular predictors for survival. Consequently, we prospectively examined gene and protein expression and EGFR mutation profiles of tumor cells, and clinical variables. Methods: Pts with advanced NSCLC (stage IIIb/IV) previously treated with platinum-based chemotherapy received 150mg/day erlotinib (Tarceva an EGFR tyrosine-kinase inhibitor) orally until disease progression. For molecular analyses, biopsies were taken from the primary lung tumor prior to erlotinib treatment. Pure tumor cells were isolated using laser-capture microdissection. For expression analysis, a microarray of 8793 genes (Human Focus Array, Affymetrix) was used. Data were analyzed using VSN method and significance analysis of microarrays. Results: In an interim analysis, clinical data were available for 36 of 43 so far included pts in the ongoing phase II study. For 36 pts, the tumor responses were: 1 CR (3%), 4 PR (11%), 11 SD (30%) and 19 PD (53%), and the median survival was 20 wks. Overall survival was significantly better in pts with rash than without rash: 9.2 vs 4.3 months. In a 14 months follow up, all of the responding pts survived while the median survival for pts with SD or PD was 11.4 and 4.0 months, respectively. Comparing gene expression profiles of tumors from 6 pts with a response or SD with those from 13 pts with tumor progression, we could not identify genes that were differentially expressed with sufficient significance. In 20 tumor samples evaluated for EGFR protein expression and mutation analysis, 19 expressed EGFR (IHC). A base exchange in exon 18 (2166G>A; A722A) and 20 (2547A>G; Q787Q) of the EGFR already described as a single nucleotide polymorphism was seen in 4 samples performing SSCP gel electrophoresis and sequencing. Conclusions: Rash, a side effect with erlotinib, was significantly associated with better survival. No activating EGFR mutations were found indicating that the response in 14% of pts is independent of mutations. For identification of genes predictive for response to erlotinib, a larger sample number is necessary.

No significant financial relationships to disclose.

Diagnosis of fetal infection with porcine parvovirus by in situ hybridization

In situ hybridization (ISH) for the diagnosis of fetal infection with porcine parvovirus (PPV) was compared with immune electron microscopy (IEM) and serology by immunofluorescence (IF) for its sensitivity and its applicability in a routine diagnostic laboratory. The technique was applied to the examination of sections of formalin-fixed paraffin-embedded tissues from 68 fetuses. Fifty-three of these fetuses were diagnosed serologically since they had a crown rump length of more than 17 cm, i.e. they were mature enough to mount a humoral immune response; 38 were positive and 15 negative. Eleven out of 15 smaller fetuses examined for the presence of viral antigen by immune electron microscopy (IEM) were positive and 4 were negative. Heart and lung were found to be the most suitable organs for in situ hybridization. In situ hybridization yielded a positive result in 8 of the 11 IEM positive fetuses and in 33 of the 38 serologically positive fetuses. No signal was detected in any of the 4 IEM or the 13 serologically negative fetuses. Expenses for IEM were estimated to be 179% of the expenses for ISH. Expenses for serology by IF on the other hand were 67% of the expenses for ISH. From this it was concluded that the most efficient way to diagnose a fetal infection with PPV was serology by IF, if possible with samples from several fetuses and that the other techniques, IEM or ISH, ought to be reserved for those cases where no immunocompetent fetuses were available for diagnosis.

Panleukopenia-like syndrome of FeLV caused by co-infection with FeLV and feline panleukopenia virus

To study the effect of interferon on feline leukemia virus (FeLV) infection, 30 specific pathogen free (SPF) cats were infected with the apathogenic FeLV A Glasgow. Unexpectedly, between 5 and 8 weeks after FeLV infection, all 19 cats with persistent FeLV infection but not the FeLV-negative cats died from a panleukopenia-like syndrome. No feline panleukopenia virus (FPLV) antigen was found in feces by latex agglutination, enzyme-linked immunosorbent assay (ELISA) or immunoelectron microscopy. No enteropathogenic bacteria were found. Histopathology revealed changes resembling those of FPLV infection such as destruction of crypts and pancytopenia of bone marrow. Neither clinical signs nor seroconversion to FPLV could be induced by transmitting intestinal extracts to two SPF cats. However, FPLV antigen was demonstrated by immunofluorescence assay in intestinal cryostat sections of diseased animals. FPLV could also be demonstrated in intestinal extracts by immunoelectron microscopy, by latex agglutination and ELISA after anti-FPLV antibodies were removed from immune-complexed FPLV by ultracentrifugation over a CsCl gradient at pH 2.0. From these experiments it was concluded that the panleukopenia-like syndrome of FeLV may not be caused by FeLV alone but at least in some cases by co-infection with FeLV and FPLV. In addition, some form of 'cooperation' between FeLV and FPLV must be postulated because neither virus alone induced symptoms.

Preliminary characterization of a monoclonal antibody specific for a viral 27 kD glycoprotein family synthesized in porcine epidemic diarrhoea virus infected cells

We describe a new monoclonal antibody No. 204 (mcAb 204) which recognized a family of four polypeptides, consisting of a 27kD, a 24/23kD double band and a 19kD protein present within PEDV infected cell lysates. These proteins were identified by immunoprecipitation as well as by staining of immunoblots. In infected Vero cell cultures, the synthesis of the 27kD protein was initiated between 6 and 8 hours post inoculation. The 24/23kD double band and the 19kD protein were only detectable later. At least the 27 and the 24/23kD proteins were apparently glycosylated and present in purified virions. Pulse-chase as well as solubilization experiments indicated that the faster migrating bands represented processed products of the 27kD glycoprotein. The nature of the processing is not known at present. We suggest that the 27kD protein family may represent the integral membrane protein M of PEDV. Since this protein is highly abundant in virions as well as in infected cells, and since mcAb 204 is able to react with its antigen under various conditions, this monoclonal antibody may be useful to further studies of the M-protein of PEDV. In addition, it may provide a useful tool for routine diagnosis.

[The infectious causes of abortion and stillbirth in swine in Switzerland]

Fetuses and placentae of 171 cases of porcine abortion, stillbirth and mummification were examined for pathological lesions, bacterial infections and PPV (porcine parvovirus) infection. Furthermore IgG (immunoglobulin G) levels were determined in fetal body fluids. Selected maternal sera were tested for antibodies against Leptospira, Aujeszky's disease and hog cholera. PPV infection was diagnosed in 29.2% of all cases. Bacterial abortion was diagnosed in 8.2%. Indications for an infectious agent were demonstrated in about 10% of the cases. The etiology of the abortion could not be identified in 52%. Inflammatory alterations in association with the isolation of bacteria consisted of neutrophilic infiltration and necrosis and were of particular value to differentiate bacterial contamination from infection. Infiltrations of mononuclear leucocytes in brain, leptomeninx, kidney or myocard were observed in about 50% of the fetuses with PPV infection. IgG levels were consistently elevated in fetuses serologically positive for PPV, but also in two fetuses, where no infectious agent could be identified.