Infection dynamics and persistence of hepatitis E virus on pig farms - a review.

BACKGROUND: Hepatitis E virus (HEV) genotype 3 and 4 is a zoonosis that causes hepatitis in humans. Humans can become infected by consumption of pork or contact with pigs. Pigs are the main reservoir of the virus worldwide and the virus is present on most pig farms. MAIN BODY: Though HEV is present on most farms, the proportion of infected pigs at slaughter and thus the level of exposure to consumers differs between farms and countries. Understanding the cause of that difference is necessary to install effective measures to lower HEV in pigs at slaughter. Here, HEV studies are reviewed that include infection dynamics of HEV in pigs and on farms, risk factors for HEV farm prevalence, and that describe mechanisms and sources that could generate persistence on farms. Most pigs become infected after maternal immunity has waned, at the end of the nursing or beginning of the fattening phase. Risk factors increasing the likelihood of a high farm prevalence or proportion of actively infected slaughter pigs comprise of factors such as farm demographics, internal and external biosecurity and immunomodulating coinfections. On-farm persistence of HEV is plausible, because of a high transmission rate and a constant influx of susceptible pigs. Environmental sources of HEV that enhance persistence are contaminated manure storages, water and fomites. CONCLUSION: As HEV is persistently present on most pig farms, current risk mitigation should focus on lowering transmission within farms, especially between farm compartments. Yet, one should be aware of the paradox of increasing the proportion of actively infected pigs at slaughter by reducing transmission insufficiently. Vaccination of pigs may aid HEV control in the future.

Cardiorespiratory fitness in a representative sample of Belgian firefighters.

BACKGROUND: An important aspect of occupational health surveillance of firefighters is cardiorespiratory fitness. In Belgium, representative data on firefighters' cardiorespiratory fitness assessed in a standardized way are lacking. AIMS: To report data on cardiorespiratory fitness, body mass index (BMI) and total body fat percentage in a large cohort of Belgian firefighters; to relate the data on cardiorespiratory fitness to the new Belgian criteria and to explore the relationship of cardiorespiratory fitness with age, BMI and total body fat. METHODS: VO2-max was assessed in male firefighters by maximal exercise test on a treadmill. Total body fat percentage was assessed by dual-energy X-ray absorptiometry. Stratified analyses of mean VO2-max and proportions of subjects that did not meet the criteria were performed for different age, total body fat percentage and BMI categories. Relationships between VO2-max and the continuous variables were explored in univariate (correlation coefficients) and multivariate analyses (multiple linear regression analysis). RESULTS: In 1225 participating firefighters (96% participation rate), mean VO2-max was 46.5 ml/kg/min. Percentages of subjects that did not meet the criteria ranged from 1 to 83% depending on age, BMI and total body fat percentage. Both in univariate and multivariate analyses, strongly significant relationships were found between VO2-max and age, BMI and total body fat percentage, the latter being the strongest predictor. CONCLUSIONS: The study provided representative data on cardiorespiratory fitness, BMI and total body fat percentage for Belgian firefighters. The findings suggest the need for a structural approach on healthy eating and regular physical exercise in firefighters.

[Osteoradionecrosis of the jaw, presumably caused by a removable partial denture]. / Osteoradionecrose van de mandibula, vermoedelijk veroorzaakt door een frameprothese.

An 81-years-old man developed a severe osteoradionecrosis of the mandible following surgery and radiotherapy in the head and neck area as a result of a carcinoma at the front ofthe floor of the mouth. Presumably, the osteoradionecrosis had been developed by an injury of the oral mucosa due to a removable partial denture. There are no uniform guidelines for the treatment of osteoradionecrosis of the jaw bones. Treatment modalities vary from removal of sequesters, sometimes long-term use of antibiotics, treatment with hyperbaric oxygen and wide surgical resection with or without reconstruction of the jaw.

Low prevalence of methicillin-resistant Staphylococcus aureus (MRSA) at hospital admission in the Netherlands: the value of search and destroy and restrictive antibiotic use.

In the Netherlands, less than 1% of clinical isolates of Staphylococcus aureus are methicillin-resistant (MRSA). A national search and destroy policy prevents MRSA from becoming endemic. Some MRSA outbreaks cannot be related to patients at risk for MRSA carriage. This study was designed to measure the prevalence of MRSA among patients without risk factors for MRSA carriage at the time of admission to the hospital. In four Dutch hospitals, patients admitted to non-surgical departments in the period 1999-2000 were screened for MRSA nasal carriage. Nasal swabs were streaked on 5% sheep blood agar (BA), submerged in a selective broth, and incubated for two to three days at 35 degrees C. Colonies suspected of being S. aureus were identified with an agglutination test. Susceptibility testing was performed by an automated system and additional oxacillin disk diffusion. Methicillin resistance was confirmed by a DNA hybridization test and mecA PCR. MRSA strains were genotyped by pulsed-field gel electrophoresis (PFGE). Twenty-four percent (2332/9859) of the patients were S. aureus nasal carriers. Only three (0.03%) patients were MRSA carriers. These patients were not repatriated, nor known to be MRSA carriers before screening. Genotyping revealed that the strains were not clonally related and were not related to MRSA outbreaks in the hospital where the patients were admitted. We conclude that at routine admission to a Dutch hospital (excluding high-risk foreign admissions) the MRSA prevalence is low (0.03%), due to the Dutch search and destroy policy and restrictive antibiotic prescribing.

Pediatric renal transplantation in the Netherlands.

In the Netherlands, pediatric kidney transplantation programs are available in four centers. We retrospectively analyzed the results obtained over the past decade. Between 1985 and 1995, 231 patients (139 boys) received 269 transplants, including 61 repeat. The recipients were aged 1.9-21.8 yrs (mean 10.9), the donors 0.3-63.3 yrs (median 11.4, mean 19.7). Immunosuppression consisted of corticosteroids, cyclosporin A and azathioprine, in various combinations and dosages. The patient survival during follow-up was 97%. The overall graft survival was 73% at 1 yr and 60% at 5 yrs after transplantation. Major causes of graft loss were acute rejection (21%), thrombosis (12%) and chronic rejection (28%). Acute rejection episodes were noted in 74% of all grafts. First acute rejection episodes had a moderate predictive value for graft loss (relative risk (RR), compared to rejection-free grafts, 5.9). First rejection episodes occurring later than 3 months after transplantation were considerably more predictive (RR 18.3) than early ones. Grafts from living related donors (n = 35) yielded a superior 5-yr graft survival (77%) and remained free of rejection more often than grafts from adult cadaveric donors(43% vs. 25%). The results of pre-emptive transplants were excellent (n = 13, 5-yr survival 100%). Repeat transplants had the same results as primary transplants. Recipients younger than 4 yrs showed a poor 5-yr graft survival of 38% (n = 13). Single kidney grafts from donors younger than 4 yrs (n = 35) had a 5-yr graft survival of 44%. In contrast, kidneys from these young donors did well if transplanted en bloc (n = 10, 5-yr graft survival 89%). These overall results are in line with those of others. The results may be improved by expansion of immunosuppressive therapy in the first year and by thrombosis prophylaxis in high-risk patient-donor combinations. Better results may be expected from more extensive use of living related donations, pre-emptive transplantation and en bloc transplantation instead of single kidneys of young donors.

Examination of Raynaud's phenomenon in traumatic vasospastic disorders.

Certain types of occupation-related vibrations can cause traumatic vasospastic disorders. Findings from clinical examination are often normal at the office consultation. Measurements of finger blood flow using plethysmography while the local ambient temperature is changed can give important information about the severity of traumatic vasospastic disorder and the concomitant disability. This technique can also be used for follow-up of the finger blood flow after withdrawal from vibrations.