Hepatitis E virus infection: an emerging occupational risk?

BACKGROUND: Hepatitis E virus (HEV) infection is endemic in many developing countries, causing substantial morbidity. Transmission is primarily faeco-oral and is associated with both sporadic infections and epidemics in areas where poor sanitation and weak public health infrastructures exist. Recently, it has become clear that HEV is also an endemic disease in industrialized countries. Moreover, a porcine reservoir and growing evidence of zoonotic transmission have been reported in these countries, suggesting the possibility of occupational transmission to man. AIMS: To summarize the current knowledge on the epidemiology and prevention of transmission of HEV infection in occupational settings. METHODS: The following key words were used to explore PubMed: hepatitis E, disease, epidemiology, profession(al), occupation(al). RESULTS: After screening of the results, 107 publications were retained. In non-endemic regions, seroprevalence varied from a few per cent (2-7.8%) in Europe, Japan and South America to 18.2-20.6% in the USA, Russia, UK, southern France and Asia. A meta-analysis of 12 cross-sectional studies evaluating HEV immunoglobulin G (IgG) seroprevalence in individuals occupationally exposed to swine showed greater odds of seropositivity in the exposed group but also a high degree of heterogeneity. A funnel plot suggested publication bias. CONCLUSIONS: There was a significant association between occupational exposure to swine and HEV IgG seroprevalence, but the level of prevalence detected depended also on the type of HEV IgG kits used. Further research, including on mechanisms and risk factors for infection, as well as the development of better serological tests for identification of infection, is required.

A large community outbreak of gastroenteritis associated with consumption of drinking water contaminated by river water, Belgium, 2010.

SUMMARY On 6 December 2010 a fire in Hemiksem, Belgium, was extinguished by the fire brigade with both river water and tap water. Local physicians were asked to report all cases of gastroenteritis. We conducted a retrospective cohort study among 1000 randomly selected households. We performed a statistical and geospatial analysis. Human stool samples, tap water and river water were tested for pathogens. Of the 1185 persons living in the 528 responding households, 222 (18·7%) reported symptoms of gastroenteritis during the time period 6-13 December. Drinking tap water was significantly associated with an increased risk for gastroenteritis (relative risk 3·67, 95% confidence interval 2·86-4·70) as was place of residence. Campylobacter sp. (2/56), norovirus GI and GII (11/56), rotavirus (1/56) and Giardia lamblia (3/56) were detected in stool samples. Tap water samples tested positive for faecal indicator bacteria and protozoa. The results support the hypothesis that a point-source contamination of the tap water with river water was the cause of the multi-pathogen waterborne outbreak.

Epidemiology of pertussis in children of Flanders Belgium: can healthcare professionals be involved in the infection?

Pertussis is a communicable disease whose registration incidence in the Flemish region of Belgium has increased since 2003. Originally, this increment was obvious only in the province of Antwerp, but since 2012, there has also been an increase in the registered cases of pertussis in other Flemish provinces. The overall registration incidence for pertussis in Flanders was 5·6 per 100 000 in 2012. The majority of these cases were identified among young children, but older children and adults were also affected. Increased awareness, new diagnostic tools, better registration, waning immunity, and circulation of new strains were most likely associated with the increase in reporting. Although many of the pertussis infections we studied occurred within family units, several healthcare workers who had been in contact with young children were also identified as sources of pertussis. A number of these were index cases, while others were secondary infections. Finally, a fatal neonatal pertussis case is presented to illustrate the severity of the disease in young unvaccinated children.

Usefulness of the European Epidemic Intelligence Information System in the management of an outbreak of listeriosis, Belgium, 2011.

A cluster of time-linked cases and the identification of a clonal strain suggest the occurrence of an outbreak of listeriosis in Belgium in 2011, presumably due to the consumption of hard cheese made with pasteurised milk and produced by a Belgium manufacturer. The outbreak clone was identified as Listeria monocytogenes serovar 1/2a, sensitive to arsenic and cadmium and of multilocus sequence typing MLST-type 37. Food investigation of this outbreak was facilitated by the European Epidemic Intelligence Information System and data exchanged between French and Belgium listeriosis surveillance systems.

Outbreak of Shigella sonnei infections in the Orthodox Jewish community of Antwerp, Belgium, April to August 2008.

In the beginning of April 2008 three cases of Shigella sonnei infection were identified among the Orthodox Jewish community of Antwerp, Belgium. We conducted a descriptive study and a household cohort study to identify potential risk factors. Stool samples were cultured and antibiotic susceptibility of the isolates was determined. Between April and August 2008, 42 cases were registered. All characterised isolates (n=20) shared an identical pulsed-field gel electrophoresis profile and were indistinguishable from one of the twelve main strains detected in Israel in 2008, where the index case's father had stayed before the outbreak. The secondary attack rate in households was 8.5% (95% confidence interval (CI): 4.3­12.7). Multivariate analysis identified the following risk factors for secondary spread: households with more than three children (adjusted relative risk (RR): 9.17; 95% CI: 1.21­69.13), children younger than five years (adjusted RR: 5.45; 95% CI: 2.44­12.62), and children younger than 12 years assisting in washing younger siblings (adjusted RR: 5.45; 95% CI: 2.44­12.17). Rigorous hand washing, use of disposable towels, information for parents and caregivers, and exclusion of symptomatic children from day care, preschool and school for a minimum of 48 hours were implemented.

Shigellosis outbreak linked to canteen-food consumption in a public institution: a matched case-control study.

On 13 November 2009, the authorities of Flemish Brabant, Belgium, received an alert concerning a potential outbreak of Shigella sonnei at a public institution. A study was conducted to assess the extent, discover the source and to implement further measures. We performed a matched case-control study to test an association between shigellosis and canteen-food consumption. Water samples and food handlers' faecal samples were tested. The reference laboratory characterized the retrospectively collected Shigella specimens. We found 52 cases distributed over space (25/35 departments) and time (2 months). We found a matched odds ratio of 3·84 (95% confidence interval 1·02-14·44) for canteen-food consumption. A food handler had travelled to Morocco shortly before detection of the first laboratory-confirmed case. Water samples and food handlers' faecal samples tested negative for Shigella. Confirmed cases presented PFGE profiles, highly similar to archived isolates from Morocco. Foodborne transmission associated with the canteen was strongly suspected.

An outbreak of measles in orthodox Jewish communities in Antwerp, Belgium, 2007-2008: different reasons for accumulation of susceptibles.

From August 2007 to May 2008, an outbreak of at least 137 cases of measles occurred in some orthodox Jewish communities in Antwerp, Belgium. The outbreak was linked to outbreaks in the same communities in the United Kingdom and in Israel. The reasons for this outbreak were diverse: cultural factors, misinformation on vaccination by some medical doctors and the lack of a catch-up vaccination programme in private Jewish schools. The identification of smaller susceptible groups for measles transmission and vaccination of these groups represent a major challenge for the measles elimination programme.

Outbreak of verocytotoxin-producing E. coli O145 and O26 infections associated with the consumption of ice cream produced at a farm, Belgium, 2007.

In October 2007, an outbreak of verocytotoxin-producing Escherichia coli (VTEC) O145 and E. coli O26 occurred among consumers of ice cream produced and sold in September 2007 at a farm in the province of Antwerp (Belgium). The ice cream was consumed at two birthday parties and also eaten at the farm. Five children, aged between two and 11 years, developed haemolytic uraemic syndrome (HUS), and seven other co-exposed persons contracted severe diarrhoea. In three of the five HUS cases VTEC O145 infections were laboratory confirmed, one in association with VTEC O26. Identical isolates of E. coli O145 and O26 were detected with PCR and PFGE in faecal samples of patients and in ice cream leftovers from one of the birthday parties, in faecal samples taken from calves, and in samples of soiled straw from the farm at which the ice cream was produced. Ice cream was made from pasteurised milk and most likely contaminated by one of food handlers.

An outbreak of nosocomial hepatitis B virus infection in a nursing home for the elderly in Antwerp (Belgium).

After notification of a case of fulminant hepatitis B virus (HBV) infection in a 83-year-old female resident of a nursing home to the Flemish Health Inspectorate, a seroepidemiological study and a retrospective cohort study were conducted among the 94 residents and 47 nursing staff to assess the extent of HBV transmission and to identify risk factors. Susceptible residents were vaccinated against HBV and their serological response to hepatitis B vaccination determined. From December 2002 to April 2003, five residents with acute hepatitis B infection were identified with an attack rate of 5.5% and a case fatality rate of 40%. Three other residents were identified as HBV surface antigen and e-antigen positive carrier. None of the nursing staff tested positive for acute HBV infection or HBV carriage. Diabetic patients who were exposed to a shared finger-stick device for blood sampling were 10.7 times more likely to contract an acute HBV infection (RR 10.7; 95% CI 1.3-91.3). Other potential risk factors were undergoing podiatric care and being exposed to the shared razor blade of the hairdresser. The transmission of the infection could be controlled by restricting the use of finger-stick capillary sampling devices to individual patients, assigning separate glucometers to individual patients and, implementation of standard infection-control recommendations like wearing gloves and performing hand hygiene by the nursing staff, assigning separate podiatric sets to individual patients. HBV vaccination of the residents with three doses of HBV vaccine has not induced a sufficient degree of protection. The outbreak stresses the need for appropriate and generally applied standard procedures in nursing homes to prevent bloodborne pathogens.

An outbreak of Legionnaire's disease among visitors to a fair in Belgium in 1999.

This paper describes an outbreak of Legionnaire's disease at Kapellen in Belgium among visitors of the annual fair. The investigation started on 13th November 1999 after a respiratory physician notified the health authorities of the province of Antwerp of presumptive cases of legionellosis. The annual commercial fair at Kapellen, a small town in northern Belgium, was held 10 days previously and attracted 50,000 visitors. Stand employees (professionals or volunteers), technical staff of the hall and visitors at the fair were affected cases. An exploratory case-control study was conducted to trace the source of the epidemic. To complete the inventory study and to evaluate other risk factors, a cohort study of exhibitors and staff was conducted. Ninety-three people met the case definition, 41 of whom were considered as confirmed, 14 as presumptive cases and 38 as possible/clinical cases. Five people died. Further testing at the reference laboratory confirmed all strains to be Legionella pneumophila serogroup 1. The sensitivity for culture was low (29.2%), and sensitivity for seroconversion was high (90.9%). For urinary antigen test, a sensitivity with Biotest EIA of 65.6% was found, and the sensitivity of polymerase chain reaction (PCR) was 85.7%. In all cases, the individual had visited the fair. Those individuals working in the central areas of the tent, near the aerosol-producing devices, were at higher risk of disease. Legionella was detected by PCR on swabs of the surfaces of the whirlpool. Although not fully proven, an aerosol-producing device was the most probable source of the outbreak.

The difficult quest for data on "vanishing" vaccine-preventable infections in Europe: the case of measles in Flanders (Belgium).

We aimed to describe the impact of vaccination on the epidemiology of measles infection in Flanders (Belgium), to document probable vaccination coverage based on this evidence, compare these epidemiological data with those generated by a mathematical model and estimate the costs of morbidity from measles. In contrast to previous analyses, we included the costs of long-term care for sequelae due to encephalitis and subacute sclerosing panencephalitis (SSPE). We estimated the direct health care costs per average measles case at 227, 212, 210, 200 and 194 for the age groups of 0-4, 5-9, 10-14, 15-19 and > or=20 years, respectively. Excluding long-term care lowers these estimates by 22-51%, depending on the age group. By including indirect time costs, we arrive at total costs per measles case of 320, 305, 210, 200 and 625, respectively. In addition to registering vaccination coverage more rigorously in the future, it seems necessary to undertake seroprevalence studies to document the age-specific immunity to measles. By using such information, current vaccination strategies can be adapted to prevent future outbreaks and to help eliminate measles from Europe in an efficient way. We noted throughout that many of the data sources are flawed. Better and accessible data bases are required to improve the reliability of similar studies in the future.

An outbreak of diarrhoeic shellfish poisoning in Antwerp, Belgium.

In Antwerp, Belgium, 403 cases of diarrhoeic shellfish poisoning were reported after consumption of blue mussels. Symptoms included diarrhoea, vomiting, abdominal pain, and nausea. The analysis of faecal specimens from patients allowed diagnosis exclusions for bacteria and viruses. Mouse-assays revealed the presence of biotoxins specific of dinoflagellates, which were identified and quantified by LC-MS. The mussels were imported from Denmark, and were part of a batch presenting high concentrations of okadaic acid above the regulatory limits.

An outbreak of legionnaire s disease among visitors to a fair in Belgium, 1999.

Ninety-three cases of legionnaires disease (43 confirmed, 12 presumptive, and 38 possible/ clinical) were identified in an outbreak associated with a trade fair in Kapellen, Belgium in November 1999. Five cases died. Epidemiological investigation showed

Analysis of foodborne disease in Belgium in 1997.

Foodborne disease represents a major problem for public health in industrialized countries, albeit with a low lethality. Foodborne diseases are defined as a group of viral, bacterial or parasitic gastrointestinal infections transmitted by means of food. Proper food-hygiene practices and surveillance of individual diseases and in particular outbreaks are the first steps in targeting their prevention. The incidence of this illness is difficult to estimate. In the Netherlands a yearly incidence of gastrointestinal infections of 500 per 1,000 inhabitants is estimated, of which most are foodborne. To set up priorities in the actions to undertake, to establish the most frequent risks, to develop preventive efforts and to answer to international requirements, accurate data on foodborne disease from Belgium are required. In order to co-ordinate the initiatives in the Belgian context, a working group was set up in 1995. In 1997 a total of 2,013 persons with foodborne disease were identified as part of 140 outbreaks, 22 of which occurred with 10 cases or more. Salmonella Enteritidis (88 outbreaks) was identified as the main pathogen in foodborne disease, followed by S. Typhimurium (11), S. Hadar (4). Eggs and meat products were identified as the main food-items involved, although it remains difficult to obtain proper intervention studies allowing to identify the specific cause(s). In 1997, a total of 12,732 human Salmonella isolates and 5,617 Campylobacter isolates were identified by the respective national reference laboratories. Salmonella isolates from Belgium accounted in 1997 for more than a fifth of all Salmonella isolates in the EU. The final objective of the working group is the implementation of a surveillance system for all risk factors concerned with the development of food-related illness, including an early warning system and an efficient analysis of microbiological criteria relating to human health, food and food production, including livestock. An essential element of this surveillance is communication of the results, risks and measures for prevention between all the departments, institutions and public health authorities concerned.

A cluster of airport malaria in Belgium in 1995.

In Europe 64 cases of airport malaria have been registered between 1969 and 1996, most of them in France, Switzerland and Belgium. In the summer of 1995 six cases of airport malaria occurred at the International airport of Brussels, Belgium. Of the six patients three were airport employees, three were occasional visitors. One patient died, the diagnosis was made by PCR amplification and DNA sequencing after exhumation. Two different species of Plasmodium were detected, and infections occurred on at least two different floors of the airport. An inquiry revealed that the cabin of airplanes is correctly sprayed, according to WHO recommendations, but that the inside of the hand luggage, the cargo hold, the animal compartment, the wheel bays and container flights remain possible shelters for infected mosquitoes. In a case of fever of unknown origin, airport malaria should be considered in the differential diagnosis, especially during hot summers, and when thrombocytopenia is present. Additional antimosquito measures should be generalised, encompassing highly exposed personnel, container content and handling buildings, animal cages, wheel bays, and the boundary between the sorting and the reception of luggage.

Outbreak of measles among adolescents, Belgium, 1996.

Measles was very common in Belgium before 1985, affecting 95% of children before they reached the age of 15 years. In 1984 the incidence of measles, calculated using data from a general practitioner surveillance system, was 823/100 000 inhabitants (2). Wi

A psittacosis outbreak in Belgian customs officers.

In March 1994, health authorities in Antwerp, Belgium, were informed that a member of a team of 15 customs officers had developed psittacosis. The customs officer concerned had been admitted to hospital with pneumonia 10 days after exposure to parakeets t