Influence of border disease virus (BDV) on serological surveillance within the bovine virus diarrhea (BVD) eradication program in Switzerland.

BACKGROUND: In 2008, a program to eradicate bovine virus diarrhea (BVD) in cattle in Switzerland was initiated. After targeted elimination of persistently infected animals that represent the main virus reservoir, the absence of BVD is surveilled serologically since 2012. In view of steadily decreasing pestivirus seroprevalence in the cattle population, the susceptibility for (re-) infection by border disease (BD) virus mainly from small ruminants increases. Due to serological cross-reactivity of pestiviruses, serological surveillance of BVD by ELISA does not distinguish between BVD and BD virus as source of infection. RESULTS: In this work the cross-serum neutralisation test (SNT) procedure was adapted to the epidemiological situation in Switzerland by the use of three pestiviruses, i.e., strains representing the subgenotype BVDV-1a, BVDV-1h and BDSwiss-a, for adequate differentiation between BVDV and BDV. Thereby the BDV-seroprevalence in seropositive cattle in Switzerland was determined for the first time. Out of 1,555 seropositive blood samples taken from cattle in the frame of the surveillance program, a total of 104 samples (6.7%) reacted with significantly higher titers against BDV than BVDV. These samples originated from 65 farms and encompassed 15 different cantons with the highest BDV-seroprevalence found in Central Switzerland. On the base of epidemiological information collected by questionnaire in case- and control farms, common housing of cattle and sheep was identified as the most significant risk factor for BDV infection in cattle by logistic regression. CONCLUSION: This indicates that pestiviruses from sheep should be considered as a source of infection of domestic cattle and might well impede serological BVD surveillance.

Epidemiological survey on Cryptosporidium in an Equine Perinatology Unit.

The present study aims to evaluate the prevalence, pattern of spread and risk factors for the transmission of cryptosporidiosis in foals and mares hospitalized in a University Equine Perinatology Unit, where a new subtype family of Cryptosporidium horse genotype was described by Caffara et al. (2013). Mares (36) and foals (37) hospitalized during the 2012 foaling season were included. Multiple sampling from each animal was performed (a total of 305 stool samples were collected). One hundred and eleven environmental samples (gauze swabs) were also collected before and after the breeding season. Fourteen foals were found positive for Cryptosporidium spp. by PCR in at least one sample; a total of 35 foal stool specimens were confirmed for the presence of the protozoa. Instead none of the stool specimens from mares were found positive. PCR-RFLP analysis shows Cryptosporidium parvum in 5 stool samples and Cryptosporidium horse genotype in 21. In 9 specimens, from 4 different foals, the profile was suggestive for a mixed infection. The subtyping at gp60 locus showed 2 strains as members of the subtype family IId and six of the subfamily IIa of C. parvum. Twenty isolates were identified as Cryptosporidium horse genotype subtype VIaA15G4. Five gauze swabs collected from the walls of the boxes where the animals were hosted out of 111 environmental samples examined were PCR positive for Cryptosporidium spp. Cryptosporidium parvum was detected in one sample collected before the foaling season, while Cryptosporidium horse genotype profile was observed in 4 wall samples collected at the end of the 2012 foaling season. The prevalence observed in foals (37.8%) was higher than that reported in other studies. These features and the diffusion of the same genotype point out as the EPU, where critically ill foals are hospitalized, can support the spread of cryptosporidiosis. Therefore, the manual tasks and the activities carried out in these facilities are of great importance, as they might favor the diffusion of the infection.

[Development of a real-time RT-PCR for detection of equine influenza virus]. / Entwicklung einer real-time RT-PCR zum Nachweis von equinem Influenzavirus.

Equine influenza is a highly contagious respiratory disease in horses caused by influenza A viruses. In this work a real-time RT-PCR for fast and sensitive diagnosis of equine influenza viruses (EIV) targeting a highly conserved region of the matrix gene was developed. In addition two RT-PCR methods for the amplification of large parts of the matrix- and HA gene were adapted for molecular-epidemiological characterization of viruses. The primers of the real-time RT-PCR had homologies of 99.4% to EIV- and 97.7% to all influenza A viral sequences, whereas the minor groove binder (MGB) probe showed homologies of 99.3% and 99.6%, respectively. These high values allow application of the assay for influenza viruses in other species. Using 20 equine, 11 porcine and 2 avian samples, diagnostic suitability of the assay was confirmed. High specificity for influenza viruses was shown both experimentally and by software simulation. The assay analytical sensitivity was at 10(2)-10(3) copies of RNA and 10(0)-10(1) copies of DNA, respectively. This allows virus detection also in circumstances of minor viral shedding. All amplified EIV sequences were classified phylogenetically within the known lineages.

Presence of Campylobacter and Arcobacter species in in-line milk filters of farms authorized to produce and sell raw milk and of a water buffalo dairy farm in Italy.

The objectives of this study were to investigate the presence of Campylobacter spp. and Arcobacter spp. in dairy herds authorized for the production and sale of raw milk and in a water buffalo dairy farm, and to test the antimicrobial susceptibility of the isolates. A total of 196 in-line milk filters were collected from 14 dairy farms (13 bovine and 1 water buffalo) for detection of Campylobacter spp. and Arcobacter spp. by microbiological culture. For each farm investigated, 1 isolate for each Campylobacter and Arcobacter species isolated was tested using the Etest method (AB Biodisk, Solna, Sweden) to evaluate the susceptibility to ciprofloxacin, tetracycline, chloramphenicol, ampicillin, erythromycin, and gentamicin. A total of 52 isolates were detected in 49 milk filters in 12 farms (85.7%) out of 14 and the isolates were identified as Campylobacter jejuni (6), Campylobacter hyointestinalis ssp. hyointestinalis (8), Campylobacter concisus (1), Campylobacter fetus ssp. fetus (1), Arcobacter butzleri (22), and Arcobacter cryaerophilus (14). The small number of isolates tested for antimicrobial susceptibility precludes any epidemiological consideration but highlights that all Campylobacter isolates were susceptible to macrolides, which are the first-choice drugs for the treatment of campylobacteriosis, and that resistance to fluoroquinolones and tetracycline was detected; for Arcobacter isolates, resistance to ampicillin and chloramphenicol was detected. The sale of raw milk for human consumption by self-service automatic vending machines has been allowed in Italy since 2004 and the presence of C. jejuni in in-line milk filters confirms that raw milk consumption is a significant risk factor for human infection. The high occurrence of emerging Campylobacter spp. and Arcobacter spp. discovered in dairy farms authorized for production and sale of raw milk represents an emerging hazard for human health.

Imported human rabies in Switzerland, 2012: a diagnostic conundrum.

Human rabies is rare in Western Europe. It is not easily recognized in the absence of a history of exposure. We describe the clinical course, diagnosis and follow-up of an imported human rabies case in Switzerland. The patient, a U.S. citizen, presented at an outpatient clinic in Iraq with pain in his right shoulder on July 5, 2012. On July 8 he was transferred to a hospital in the United Arab Emirates, where he exhibited progressive encephalitis with coma. On July 29, he was transferred to a hospital in Switzerland, where he died on July 31, 2012. The autopsy showed severe encephalitis. Rabies was diagnosed by the rapid fluorescent focus inhibition test (RFFIT) and confirmed by fluorescence antibody testing (FAT) in brain smears and immunohistochemistry on paraffin-embedded brain sections. The viral strain was characterized by RT-PCR followed by sequencing and phylogenetic analysis as an American bat rabies strain associated with Tadarida brasiliensis. Close contacts and exposed health care workers received postexposure prophylaxis (PEP).

Occurrence of ε-proteobacterial species in rabbits (Oryctolagus cuniculus) reared in intensive and rural farms.

In order to investigate the occurrence of Campylobacter, Helicobacter and Arcobacter species in caecal contents of rabbits reared in intensive and rural farms, a total of 87 samples from animals belonging to 29 farms were analysed by both cultural and PCR analyses. PCR analysis directly from faecal samples detected 100% positive samples for Campylobacter genus, 3.4% for Helicobacter genus and none for Arcobacter genus. 83 out of 87 animals (95.4%) and all the 29 farms were positive for Campylobacter cuniculorum as also determined by cultural examination. Campylobacter coli and Campylobacter jejuni were isolated only from three animals reared in two rural farms. No Helicobacter and Arcobacter species were isolated. To evaluate a possible genetic variability, one strain of C. cuniculorum from each farm was analysed by Pulsed Field Gel Electrophoresis (PFGE) and Amplified Fragment Length Polymorphism (AFLP). Genotyping revealed that C. cuniculorum population is heterogeneous among the different sources and no dominant clone has spread in the investigated farms. This survey highlighted a high presence of C. cuniculorum with a high rate of intestinal colonization, low presence of C. jejuni-coli, Helicobacter spp. and any Arcobacter spp. in farmed rabbits.

Quantitative risk assessment of verocytotoxin-producing Escherichia coli O157 and Campylobacter jejuni related to consumption of raw milk in a province in Northern Italy.

A quantitative risk assessment was developed to describe the risk of campylobacteriosis and hemolytic uremic syndrome (HUS) linked to consumption of raw milk sold in vending machines in Northern Italy. Exposure assessment considered the microbiological status of dairy farms, expected milk contamination, storage conditions from bulk tank to home storage, microbial growth during storage, destruction experiments, consumption frequency of raw milk, age of consumers, serving size, and consumption preference. The differential risk between milk handled under regulation conditions (4°C throughout all phases) and the worst field handling conditions was considered. The probability of Campylobacter jejuni infection was modeled with a single-hit dose-response beta-Poisson model, whereas for HUS an exponential dose-response model was chosen and two probabilities were used to model the higher susceptibility of children younger than 5 years old. For every 10,000 to 20,000 consumers each year, the models predicted for the best and worst storage conditions, respectively, 2.12 and 1.14 campylobacteriosis cases and 0.02 and 0.09 HUS cases in the 0- to 5-year age group and 0.1 and 0.5 HUS cases in the >5-year age group. The expected pediatric HUS cases do not differ considerably from those reported in Italy by the Minister of Health. The model developed may be a useful tool for extending the assessment of the risk of campylobacteriosis and HUS due to raw milk consumption at the national level in Italy. Considering the epidemiological implications of this study, the risk of illness linked to raw milk consumption should not be ignored and could be reduced by the use of simple measures. Boiling milk before consumption and strict control of temperatures by farmers during raw milk distribution have significant effects on campylobacteriosis and HUS and are essential measures for risk management.

Isolation of glucosidase and phospholipase positive Bacillus circulans on ALOA medium.

AIM: To report the growth of glucosidase and phospholipase positive bacteria on agar Listeria according to Ottaviani and Agosti (ALOA) different from Listeria monocytogenes, Listeria ivanovii and Bacillus cereus. METHODS AND RESULTS: Raw water-buffalo milk was analysed according to EN ISO 11290. Streaking of Fraser broth on ALOA resulted in green colonies with an opaque halo after 48 h at 30°C. Colonies were transferred onto Tryptone soya yeast extract agar and showed cultural characteristics atypical for L. monocytogenes. Results of confirmation tests according to EN ISO 11290 method: negative haemolysis test, weak positive camp test in correspondence with Staphylococcus aureus, no fermentation of rhamnose, fermentation of xylose. Gram staining showed tapered, curved, Gram-positive rods with subterminal to terminal ellipsoidal spores, 0.5-0.7 µm diameter 4-5 µm. API 50CH CHB kit (99.9% percentage of identification) and the sequence of the 833 bp PCR product (portion of 16S rRNA, generic primers 1492-r; p27-f) showed 97% identity with Bacillus circulans ATCC 4513 (GenBank AY724690). CONCLUSIONS: Some B. circulans strains can grow on ALOA, according to ISO 11290, confirmation tests readily differentiate B. circulans from L. monocytogenes. SIGNIFICANCE AND IMPACT OF THE STUDY: The different morphology of the colonies must be kept in mind to select true L. monocytogenes for confirmation test and to avoid overestimation of L. monocytogenes count.

Walking the dog and moving the cat: rabies serology in the context of international pet travel schemes.

Data of 13'469 blood samples from 10'999 dogs and 2'470 cats tested for rabies neutralizing antibodies within the framework of pet travel schemes were analysed for single and combined factors influencing antibody titres and failures. The time span between vaccination and drawing the blood sample was confirmed as a major source of failure in dogs with a proportion of 23 % at 4 months after primary vaccination (single dose). Failures in dogs and cats (titre < 0.5 IU) were significantly reduced after double primary vaccination (2 doses within 7 - 10 days), although failures reached comparable levels in dogs as early as 6 months after vaccination. In contrast, failure after vaccination was generally below 5 % in dogs and absent in cats after a booster applied at earliest 12 months after single primary vaccination. Statistically significant differences between the failures of the vaccine brands «Rabisin¼ (1.5 %), «Defensor¼ (6.7 %), «Nobivac Rabies¼ (11.0 %) and «Rabdomun¼ (18.2 %) were found in dogs but also between the titres induced in cats. Significant differences were found between different dog breeds with some small breeds showing a significantly higher responsiveness. Taken together, a new regimen for rabies vaccination consisting of double primary vaccination with a short interval of 7 - 10 days and a one-year booster appears to be highly recommended for dogs and cats.

Occurrence of Mycobacterium spp. in ornamental fish in Italy.

The occurrence of Mycobacterium spp. in freshwater and marine ornamental fish was studied in Italy from June 2002 to May 2005. Two surveys were carried out, one of aquarium fish sent to the Laboratory for diagnosis, and the other of prevalence of infection by mycobacteria in ornamental fish imported into Italy. Bacterial isolation was carried out from the spleen, kidney and liver, and the isolates were subsequently identified by biochemical tests. In the first survey, 387 fish were examined and Mycobacterium spp. were isolated from 181 (46.8%) fish. In the second survey 127 batches of ornamental fish from different countries were examined. Mycobacterium spp. were isolated from 38 (29.9%) batches. The following species were found: M. fortuitum, M. peregrinum, M. chelonae, M. abscessus, M. marinum, M. gordonae, M. nonchromogenicum and M. interjectum. There was a high prevalence of infection independent of the presence of macroscopic lesions. Mycobacterium fortuitum and M. chelonae were more prevalent than M. marinum in the samples examined.

Occurrence and species level diagnostics of Campylobacter spp., enteric Helicobacter spp. and Anaerobiospirillum spp. in healthy and diarrheic dogs and cats.

In order to study the occurrence and co-infection of different species of Campylobacter, enteric Helicobacter and Anaerobiospirillum in dogs and cats and define a possible association between these microrganisms and gastrointestinal disorders, 190 dogs and 84 cats, either healthy or with diarrhea, were sampled between 2002 and 2003. Thirty-three C. upsaliensis, 17 C. jejuni, 2 C. helveticus, 1 C. lari isolates from dogs and 14 C. helveticus, 7 C. jejuni, 6 C. upsaliensis isolates from cats were identified using species-specific PCR and phenotypic tests. Whole cell protein profile analysis, phenotypic tests, PCR-RFLP of gyrB and a phylogenetic study of partial groEL and 16S rRNA sequences were used to identify 37 H. bilis, 22 H. canis and 14 H. cinaedi in dogs and 12 H. canis, 5 H. bilis and 2 H. cinaedi in cats. Whole cell protein profile analysis, phenotypic tests and species-specific PCR of 16S rRNA were used to identify 14 A. succiniciproducens, 12 A. thomasii isolates and one unidentified Anaerobiospirillum sp. isolate in dogs and 3 A. thomasii isolates in cats. Fifty-two animals (19%) were positive for the isolation of more than one genus. No significant statistical correlation was found between any isolates of Campylobacter, Helicobacter or Anaerobiospirillum spp. or the various co-infection rates, and the presence of diarrhea in either dogs or cats. Campylobacter isolates were also tested for antibiotic resistance using the agar dilution method.

Occurrence and antibiotic susceptibility of Helicobacter pullorum from broiler chickens and commercial laying hens in Italy.

In 2005, in order to investigate the occurrence of Helicobacter pullorum in poultry, the caecal contents collected from a total of 60 animals intensively reared in Italy on 15 different farms (9 farms of broiler chicken and 6 of laying hens) were examined at the slaughterhouse. A modified Steele-McDermott membrane filter method was used. Small, greyish-white colonies of Gram-negative, gently curved, slender rod bacteria were preliminarily identified as H. pullorum by a Polymerase Chain Reaction (PCR) assay based on 16S rRNA and were then subjected to an ApaLI digestion assay to distinguish H. pullorum from Helicobacter canadensis. One isolate from each farm was phenotypically characterized by biochemical methods and 1D SDS-PAGE analysis of whole cell proteins; antibiotic susceptibility was also tested. According to the PCR and PCR-RFLP results, all the animals examined were positive for H. pullorum. The 1D SDS-PAGE whole protein profile analysis showed high similarity among the 15 isolates tested. A monomodal distribution for the Minimum Inhibitory Concentrations (MICs) was found for ampicillin, chloramphenicol, gentamicin and tetracycline. For erythromycin and ciprofloxacin, a bimodal trend having a second peak at >128 micro(-1) and 32 micro(-1) was found. The isolation method used in this study seems to be highly suitable for isolating H. pullorum from chicken caecal contents. Moreover, the detection of a high number of colonies phenotypically similar to H. pullorum suggests that this microorganism, when present, colonizes the caecum at high concentration.

[Rabies-free status of Switzerland following 30 years of rabies in foxes]. / Tollwutfreiheit der Schweiz nach 30 Jahren Fuchstollwut.

The European fox rabies epizootic starting in 1939 at the eastern border of Poland reached Switzerland on March 3, 1967. Rabies spread over large parts of the country until 1977, the year it caused three human deaths. In 1978 the first field trial world-wide for the oral immunization of foxes against rabies was conducted in Switzerland. Initially, the expansion of the vaccination area led to a rapid reduction in rabies cases. However, the 1990s were characterized by a recrudescence of rabies in spite of regular oral immunization of foxes. The last endemic case of rabies was diagnosed in 1996 after an adaptation of the vaccination strategy. A total of 17,109 rabies cases, of which 73% in foxes and 14% in domestic animals were diagnosed, leading to an estimated number of some 25,000 postexposure treatments in humans. To eliminate rabies, a total of 2.8 million baits containing a modified live virus were distributed--mostly by hand--in the field.

[The development of rabies in Switzerland--landscape determines the spread of a wildlife epidemic]. / Der Verlauf der Tollwut in der Schweiz--Landschaft prägt die Ausbreitung einer Wildtierepidemie.

The rabies epidemic that reached Switzerland in 1967 developed in response to landscape factors as long as no efficient control strategies were available. The landscape acted either as barrier to the spread of rabies, or it influenced the density of red foxes and thus the habitat of the epidemic. Following the first cases in the canton of Schaffhausen, the whole northwestern Switzerland was infected followed by the eastern Alps, large parts of the Plateau and the Jura mountains. In 1978, in the canton of Valais, the first campaigns of oral immunization of foxes against rabies started. The design of vaccination campaigns during the next two decades was always closely linked to landscape features. Thus, it was possible to free first the Alps and then the Plateau from rabies and finally, at the end of the 1990s, to eliminate it completely within the country. We describe the entire development of the epidemic within the period of 30 years from the first infection up to the last registered case and the final vaccination campaign.

[The final stage of rabies in Switzerland]. / Die Endphase der Tollwut in der Schweiz.

Since summer 1989, rabies in Switzerland has been restricted to the Jura Mountains in the north-west of the country. Even there, the last endemic focus disappeared in 1990, but a re-infection in the same year caused a new flare-up of the epizootic. Until 1994, the number of rabies cases increased again to 225. Control measures were intensified with doubled vaccination campaigns, increased bait densities, and additional vaccination campaigns to immunize young foxes at the den. As a consequence, the number of cases dropped to 25 in 1995 and to 6 in 1996. On December 21, 1996, the last endemic case of rabies in Switzerland was registered. After two years of continuing vaccination campaigns and surveillance, Switzerland became officially rabies-free at the beginning of 1999. In the present paper, we analyse the final stage of the epizootic. The re-infection in 1990 was caused by infected foxes immigrating from France, but as the immunization of the fox population in Switzerland was insufficient, the disease became again endemic immediately. The lacking herd immunity was partly a consequence of problems related to the vaccination system and even more of the rapid increase of the fox population.