A population-based prevalence study of hepatitis A, B and C virus using oral fluid in Flanders, Belgium.

Ten years after the first seroprevalence study performed in Flanders, the aim of this cross sectional study was to follow the evolution of hepatitis A, B and C prevalence. The prevalence of hepatitis A antibodies, hepatitis B surface antigen and hepatitis C antibodies was measured in oral fluid samples collected by postal survey. Using the National Population Register, an incremental sampling plan was developed to obtain a representative sampling of the general population. A total of 24,000 persons were selected and 6,000 persons among them contacted in a first wave. With 1834 participants a response rate of 30.6% was achieved. The prevalence was weighted for age and was 20.2% (95% CI 19.43-21.08) for hepatitis A, 0.66% (95% CI 0.51-0.84) for hepatitis B surface antigen and 0.12% (95% CI 0.09-0.39) for hepatitis C. The prevalence of hepatitis A and C in the Flemish population is lower in 2003 compared with the results of the study performed in 1993. The difference may be due to a real decrease of the diseases but also to differences in the methodology. The prevalence of hepatitis B surface antigen remains stable. Considering the 30% response rate and the high quality of the self-collected samples as reflect of a good participation of the general population, saliva test for prevalence study is a good epidemiological monitoring tool.

Use of DNA arrays for the analysis of outbreak-related strains of Listeria monocytogenes.

We evaluated the discriminative power and usefulness of the DNA array technology as compared to DNA macrorestriction pattern analysis for monitoring epidemiologically related clusters of Listeria monocytogenes strains that differ slightly in DNA macrorestriction patterns. We show that this approach allows clarifying the genetic basis of the pattern variations. In the reported outbreak, the differences were due to phage excision, showing the power of this technique in epidemiological studies.

[Bioterrorism and health security in the European Union]. / Bioterrorisme et sécurité sanitaire dans l'Union Européenne.

A PROGRAM OF ACTION AND COOPERATION: Since 2001, a series of measures have been taken by the Member States, the European Union and the International authorities to reinforce the preparation and response to biological and chemical terrorist acts. It is essential that the Member States can mutually consult and coordinate their preparation and response as widely as possible. THE ROLE OF THE HEALTH SECURITY COMMITTEE: Together with the health security committee, the European Union has setup a mechanism of consultation and coordination that can be recommend and guide joint action in an emergency, and guarantee the coherence of the counter-actions throughout the Union. This is a committee also constitutes the framework within which the emergency strategies and model-simulations are exchange, and in which assistance in the form of expertise and other resources can be obtained among the Member States. IN THE YEARS TO COME: The future European Centre for the prevention and control of disease, the implantation and functioning of which will start in Sweden in 2005, will play a fundamental part in the harmonisation of the European response to any eventual terrorist acts, whether biological or chemical.

Bichat guidelines for the clinical management of viral encephalitis and bioterrorism-related viral encephalitis.

Most of the viruses involved in causing encephalitis are arthropod-borne viruses, with the exception of arenaviruses that are rodent-borne. Even if little information is available, there are indications that, most of these encephalitis-associated viruses could be used by aerosolisation during a bioterrorist attack. Viral transfer from blood to the CNS through the olfactory tract has been suggested. Another possible route of contamination is by vector-borne transmission such as infected mosquitoes or ticks. Alphaviruses are the most likely candidates for weaponisation. The clinical course of the diseases caused by these viruses is usually not specific, but differentiation is possible by using an adequate diagnostic tool. There is no effective drug therapy for the treatment of these diseases and treatment is mainly supportive, but vaccines protecting against some of these viruses do exist.

Bichat guidelines for the clinical management of Q fever and bioterrorism-related Q fever.

Q fever is a zoonotic disease caused by Coxiella burnetii. Its interest as a potential biological weapon stems from the fact that an aerosol of very few organisms could infect humans. Another route of transmission of C. burnetii could be through adding it to the food supply. Nevertheless, C. burnetii is considered to be one of the less suitable candidate agents for use in a bioterrorist attack; the incubation is long, many infections are inapparent and the mortality is low. In the case of an intentional release of C. burnetii by a terrorist, clinical presentation would be similar to naturally occurring disease. It may be asymptomatic, acute, normally accompanied by pneumonia or hepatitis, or chronic, usually manifested as endocarditis. Most cases of acute Q fever are asymptomatic and resolve spontaneously without specific treatment. Nevertheless, treatment can shorten the duration of illness and decrease the risk of complications such as endocarditis. Post-exposure prophylaxis is recommended after the exposure in the case of a bioterrorist attack.

Bichat guidelines for the clinical management of glanders and melioidosis and bioterrorism-related glanders and melioidosis.

Glanders and melioidosis are two infectious diseases that are caused by Burkholderia mallei and Burkholderia pseudomallei respectively. Infection may be acquired through direct skin contact with contaminated soil or water. Ingestion of such contaminated water or dust is another way of contamination. Glanders and melioidosis have both been studied for weaponisation in several countries in the past. They produce similar clinical syndromes. The symptoms depend upon the route of infection but one form of the disease may progress to another, or the disease might run a chronic relapsing course. Four clinical forms are generally described: localised infection, pulmonary infection, septicaemia and chronic suppurative infections of the skin. All treatment recommendations should be adapted according to the susceptibility reports from any isolates obtained. Post-exposure prophylaxis with trimethoprim-sulfamethoxazole is recommended in case of a biological attack. There is no vaccine available for humans.

Bichat guidelines for the clinical management of brucellosis and bioterrorism-related brucellosis.

Interest in Brucella species as a biological weapon stems from the fact that airborne transmission of the agent is possible. It is highly contagious and enters through mucous membranes such as the conjunctiva, oropharynx, respiratory tract and skin abrasions. It has been estimated that 10-100 organisms only are sufficient to constitute an infectious aerosol dose for humans. Signs and symptoms are similar in patients whatever the route of transmission and are mostly non-specific. Symptoms of patients infected by aerosol are indistinguishable from those of patients infected by other routes. Regimens containing doxycycline plus streptomycin or doxycycline plus rifampin are effective for most forms of brucellosis. Isolation of patients is not necessary. Trimethoprim-sulfamethoxazole and fluoroquinolones also have good results against Brucella, but are associated with high relapse rates when used as monotherapy. The combination of ofloxacin plus rifampicin is associated with good results. Even if there is little evidence to support its utility for post-exposure prophylaxis, doxycycline plus rifampicin is recommended for 3 to 6 weeks.

Bichat guidelines for the clinical management of botulism and bioterrorism-related botulism.

Botulism is a rare but serious paralytic illness caused by botulinum toxin, which is produced by the Clostridium botulinum. This toxin is the most poisonous substance known. It 100,000 times more toxic than sarin gas. Eating or breathing this toxin causes illness in humans. Four distinct clinical forms are described: foodborne, wound, infant and intestinal botulism. The fifth form, inhalational botulism, is caused by aerosolised botulinum toxin that could be used as a biological weapon. A deliberate release may also involve contamination of food or water supplies with toxin or C. botulinum bacteria. By inhalation, the dose that would kill 50% of exposed persons (LD50) is 0.003 microgrammes/kg of body weight. Patients with respiratory failure must be admitted to an intensive care unit and require long-term mechanical ventilation. Trivalent equine antitoxins (A,B,E) must be given to patients as soon as possible after clinical diagnosis. Heptavalent human antitoxins (A-G) are available in certain countries.

Bichat guidelines for the clinical management of haemorrhagic fever viruses and bioterrorism-related haemorrhagic fever viruses.

Haemorrhagic fever viruses (HFVs) are a diverse group of viruses that cause a clinical disease associated with fever and bleeding disorder. HFVs that are associated with a potential biological threat are Ebola and Marburg viruses (Filoviridae), Lassa fever and New World arenaviruses (Machupo, Junin, Guanarito and Sabia viruses) (Arenaviridae), Rift Valley fever (Bunyaviridae) and yellow fever, Omsk haemorrhagic fever, and Kyanasur Forest disease (Flaviviridae). In terms of biological warfare concerning dengue, Crimean-Congo haemorrhagic fever and Hantaviruses, there is not sufficient knowledge to include them as a major biological threat. Dengue virus is the only one of these that cannot be transmitted via aerosol. Crimean-Congo haemorrhagic fever and the agents of haemorrhagic fever with renal syndrome appear difficult to weaponise. Ribavirin is recommended for the treatment and the prophylaxis of the arenaviruses and the bunyaviruses, but is not effective for the other families. All patients must be isolated and receive intensive supportive therapy.

Bichat guidelines for the clinical management of tularaemia and bioterrorism-related tularaemia.

Francisella tularensis is one of the most infectious pathogenic bacteria known, requiring inoculation or inhalation of as few as 10 organisms to initiate human infection. Inhalational tularaemia following intentional release of a virulent strain of F. tularensis would have great impact and cause high morbidity and mortality. Another route of contamination in a deliberate release could be contamination of water. Seven clinical forms, according to route of inoculation (skin, mucous membranes, gastrointestinal tract, eyes, respiratory tract), dose of the inoculum and virulence of the organism (types A or B) are identified. The pneumonic form of the disease is the most likely form of the disease should this bacterium be used as a bioterrorism agent. Streptomycin and gentamicin are currently considered the treatment of choice for tularemia. Quinolone is an effective alternative drug. No isolation measures for patients with pneumonia are necessary. Streptomycin, gentamicin, doxycycline or ciprofloxacin are recommended for post-exposure prophylaxis.

Bichat guidelines for the clinical management of smallpox and bioterrorism-related smallpox.

Smallpox is a viral infection caused by the variola virus. It was declared eradicated worldwide by the Word Health Organization in 1980 following a smallpox eradication campaign. Smallpox is seen as one of the viruses most likely to be used as a biological weapon. The variola virus exists legitimately in only two laboratories in the world. Any new case of smallpox would have to be the result of human accidental or deliberate release. The aerosol infectivity, high mortality, and stability of the variola virus make it a potential and dangerous threat in biological warfare. Early detection and diagnosis are important to limit the spread of the disease. Patients with smallpox must be isolated and managed, if possible, in a negative-pressure room until death or until all scabs have been shed. There is no established antiviral treatment for smallpox. The most effective prevention is vaccination before exposure.

Bichat guidelines for the clinical management of anthrax and bioterrorism-related anthrax.

The spore-forming Bacillus anthracis must be considered as one of the most serious potential biological weapons. The recent cases of anthrax caused by a deliberate release reported in 2001 in the United States point to the necessity of early recognition of this disease. Infection in humans most often involves the skin, and more rarely the lungs and the gastrointestinal tract. Inhalational anthrax is of particular interest for possible deliberate release: it is a life-threatening disease and early diagnosis and treatment can significantly decrease the mortality rate. Treatment consists of massive doses of antibiotics and supportive care. Isolation is not necessary. Antibiotics such as ciprofloxacin are recommended for post-exposure prophylaxis during 60 days.

Bichat guidelines for the clinical management of plague and bioterrorism-related plague.

Yersinia pestis appears to be a good candidate agent for a bioterrorist attack. The use of an aerosolised form of this agent could cause an explosive outbreak of primary plague pneumonia. The bacteria could be used also to infect the rodent population and then spread to humans. Most of the therapeutic guidelines suggest using gentamicin or streptomycin as first line therapy with ciprofloxacin as optional treatment. Persons who come in contact with patients with pneumonic plague should receive antibiotic prophylaxis with doxycycline or ciprofloxacin for 7 days. Prevention of human-to-human transmission via patients with plague pneumonia can be achieved by implementing standard isolation procedures until at least 4 days of antibiotic treatment have been administered. For the other clinical types of the disease, patients should be isolated for the first 48 hours after the initiation of treatment.

Epidemiology of hepatitis C in Belgium: present and future.

Based on currently available epidemiological data, Belgium appears to belong to the low endemicity countries for hepatitis C, with an estimated annual incidence of 3/100,000 clinical cases; a survey among the Flemish population showed an overall seroprevalence of 0.87% (1993-1994). There was no statistically significant difference in anti-HCV prevalence between men and women. A significant increase of the anti-HCV prevalence with increasing age was observed. In the French Community there was an overall seroprevalence of 0.6%. Developing surveillance for hepatitis C has proven to be difficult, since it requires confirmation tests. Techniques detecting hepatitis C antibodies in saliva will replace the need for serum samples, making prevalence studies more accessible.

The dioxin crisis as experiment to determine poultry-related campylobacter enteritis.

In June 1999, the dioxin crisis, caused by dioxin-contaminated feed components, exploded in Belgium, resulting in withdrawal of chicken and eggs from the market. Through the sentinel surveillance system, a decrease in Campylobacter infections during June 1999 was noticed. A model was generated with the reports from preceding years (1994 to 1998), and a prediction of the number of infections in 1999 was calculated. The model shows a significant decline (40%) in the number of infections, mainly because of the withdrawal of poultry. The use of a disaster as an epidemiologic tool offers a unique opportunity to observe exceptional changes in the occurrence of infections or other diseases.

The European Programme for Intervention Epidemiology Training.

The European Programme for Intervention Epidemiology Training (EPIET) provides practical experience in infectious disease epidemiology. EPIET aims to create a network of professionals throughout Europe trained to use a standard approach in intervention ep