Significant increase of Echinococcus multilocularis prevalence in foxes, but no increased predicted risk for humans.

The emergence of the zoonotic tapeworm Echinococcus multilocularis, causative agent of alveolar echinococcosis (AE), poses a public health risk. A previously designed risk map model predicted a spread of E. multilocularis and increasing numbers of alveolar echinococcosis patients in the province of Limburg, The Netherlands. This study was designed to determine trends in the prevalence and worm burden of E. multilocularis in foxes in a popular recreational area in the southern part of Limburg to assess the risk of infection for humans and to study the prevalence of E. multilocularis in dogs in the adjacent city of Maastricht. Thirty-seven hunted red foxes were tested by the intestinal scraping technique and nested PCR on colon content. Additionally, 142 fecal samples of domestic dogs from Maastricht were analyzed by qPCR for the presence of E. multilocularis. In foxes, a significantly increased prevalence of 59% (95% confidence interval 43-74%) was found, compared to the prevalence of 11% (95% CI 7-18%) in 2005-2006. Average worm burden increased to 37 worms per fox, the highest since the first detection, but consistent with the prediction about the parasite population for this region. Updated prediction on the number of AE cases did not lead to an increase in previous estimates of human AE cases up to 2018. No dogs in the city of Maastricht tested positive, but results of questionnaires showed that deworming schemes were inadequate, especially in dogs that were considered at risk for infection.

Prevalence of livestock-associated MRSA in broiler flocks and risk factors for slaughterhouse personnel in The Netherlands.

To determine methicillin-resistant Staphylococcus aureus (MRSA) carriage in poultry and slaughterhouse personnel, 40 Dutch broiler flocks, in six slaughterhouses and 466 personnel were sampled. Of the employees, 26 were positive (5.6%), indicating a higher risk of exposure when compared to the general Dutch population (0.1%). This risk was significantly higher for personnel having contact with live animals (5.2%) - especially hanging broilers on the slaughterline (20.0%) - than for all other personnel (1.9%). Conventional electric stunning conferred a significantly higher risk of MRSA carriage for employees than CO2 stunning (9.7% vs. 2.0%). A total of 405 broilers were sampled upon their arrival at the slaughterhouse, of which 6.9% were positive. These broilers originated from 40 Dutch slaughter flocks of which 35.0% were positive. MRSA contamination in the different compartments of slaughterhouses increased during the production day, from 8% to 35%. Of the 119 MRSA isolates, predominantly livestock-associated MRSA ST398 was found, although 27.7% belonged to ST9 (spa type t1430). There is an increased risk of MRSA carriage in personnel working at broiler slaughterhouses, particularly those having contact with live animals.

High prevalence of methicillin resistant Staphylococcus aureus in pigs.

Recently methicillin resistant Staphylococcus aureus (MRSA) was isolated from pigs and pig farmers in The Netherlands. In order to assess the dissemination of MRSA in the Dutch pig population, we screened 540 pigs in 9 slaughterhouses, where a representative portion of Dutch pigs (63%) was slaughtered in 2005. We found 209 (39%) of the pigs to carry MRSA in their nares. Forty-four of 54 groups of 10 consecutive pigs (81%), each group from a different farm, and all slaughterhouses were affected. All MRSA isolates belonged to 1 clonal group, showing Multi-Locus Sequence Type 398 and closely related spa types (mainly t011, t108 and t1254). Three types of the Staphylococcal Chromosome Cassette (SCCmec) were found: III (3%), IVa (39%) and V (57%). All 44 tested isolates (1 isolate per group) were resistant to tetracycline, reflecting the high and predominant use of tetracyclines in pig husbandry. Twenty-three percent of the isolates were resistant to both erythromycin and clindamycin and 36% to kanamycin, gentamicin and tobramycin but only a single isolate was resistant to co-trimoxazole and none to ciprofloxacin and several other antibiotics. The percentage of MRSA positive pigs was significantly different among slaughterhouses and among groups within slaughterhouses, indicating a high prevalence of MRSA in pigs delivered from the farms as well as cross contamination in the slaughterhouses.

Surveillance of Salmonella spp. and Campylobacter spp. in poultry production flocks in The Netherlands.

In The Netherlands, a national programme for the surveillance of zoonotic bacteria in farm animals has been operative since 1997. We describe the results of the surveillance of Salmonella spp. in flocks of laying hens and broilers and of Campylobacter spp. in broiler flocks in the period 1999-2002. The prevalence of Salmonella spp. in laying-hen flocks has significantly decreased from 21.1% in 1999 to 13.4% in 2002. This decreasing trend might indicate that the control measures taken by the poultry industry were effective. S. Enteritidis was the predominant serovar in laying hens accounting for one third of the positive flocks. Although prevalence estimates for Salmonella spp. in broiler flocks did not yield a significant decreasing trend in 1999-2002, a decrease in Salmonella prevalence to 11% was measured in 2002. During the study period, S. Paratyphi B var. Java emerged in broilers to become the predominant serovar in 2002 accounting for one third of the positive flocks. The prevalence of Campylobacter spp. in broiler flocks did not increase nor decrease continuously between 1999 and 2002, which roughly corresponds with the monitoring results from the poultry industry. In this period, the estimated flock prevalence roughly averaged around 20%, with C. jejuni being the predominant species. The approach of monitoring presented in this paper can serve as a blueprint for monitoring schemes in farm animal populations to be developed in the context of the EC Zoonoses Directive.

Risk factors for the presence of Campylobacter spp. in Dutch broiler flocks.

The campylobacter status of 495 broiler flocks sampled in The Netherlands between April 1997 and December 2000 was related to farm- and flock-specific information obtained from questionnaires to identify potential risk factors for campylobacter presence. Approximately 30% of the flocks tested positive for Campylobacter spp. in at least one pooled faecal sample. Multivariable logistic regression showed significant risk increments for: ages 29-35 days (OR = 2.34) and 36-42 days (OR = 3.96) compared to 22-28 days; > or =5 broiler houses on the premises (OR = 3.02); the presence of other farm animals on the farm (OR = 1.88); the presence of animals on farms within 1 km (OR = 9.56); and summer (OR = 3.48) and fall (OR = 2.59) compared to winter. Furthermore, hatcheries differed (ORs from 5.42 to 20.2), although this variable showed strong collinearity with the variables explaining feed mill and integrated poultry operations. We also identified interaction in which an increased risk from children entering the broiler house (OR = 28.0) was diminished by the use of broiler-specific workclothes. Population attributable fractions (PAFs) suggested that animals on farms within 1 km (PAF = 0.76) and hatchery (PAF = 0.67) had the highest impacts on campylobacter presence in Dutch broiler flocks. These factors, however, lack an easy interpretation of the mechanism behind the suggested effect.

Marker antigens to assess exposure to molds and their allergens. II. Alternaria alternata.

The estimation of exposure to molds and their products in the indoor environment, which may lead to the occurrence of allergies or respiratory complaints, by means of enumeration of viable parts is inadequate. Therefore, other methods must be developed. When grown under various circumstances (22 degrees C and 30 degrees C, high and low water activity) under laboratory conditions, Alternaria alternata produces one antigen that can be found under all studied growth conditions in extracts of the water-soluble portion of the mycelium. This common antigen may serve as marker antigen for exposure to A. alternata and its allergens. In extracts of the culture filtrate, three antigens, designated index antigens, have been identified that together may have the function of marker for the exposure to allergens of A. alternata.

Marker antigens to assess exposure to molds and their allergens. I. Aspergillus fumigatus.

BACKGROUND: Exposure to molds and mold products in the indoor environment may lead to allergies, asthma, or respiratory complaints in general. Enumeration of viable parts of molds in the environment is insufficient to estimate exposure. Therefore, other methods have to be developed. METHODS: Aspergillus fumigatus (Af) was grown under various circumstances (22 degrees C and 30 degrees C, high and low water activity) in the laboratory. At various moments during culture, extracts were taken, and antigen and allergen content was examined by acrylamide electrophoresis and immunoblot. RESULTS: In extracts of the culture filtrate, two antigens were found to be produced under all studied growth conditions (common antigens). In the extracts of the water-soluble portion of the mycelium, one common antigen was found. CONCLUSIONS: The three common antigens may serve as marker antigens for exposure to Af and its products. In view of the simultaneous presence of two of these common antigens with Af allergens, these two marker antigens may be used to estimate exposure to allergens of Af.

Immunoblotting technique for the detection of allergens of Aspergillus fumigatus: influence of Nonidet P-40 on the sensitivity.

Immunoblotting provides a useful technique for the study of antigens, antibodies and allergens. To overcome problems regarding the loss of antigenic properties during the blotting and developing procedures, several solutions have been described. The inclusion of Nonidet P-40, recommended to increase the sensitivity of developing procedures for immunoblots, in an existing procedure for the detection of allergens of Aspergillus fumigatus, however, led to decreased sensitivity of the method.