Brussels, 06 Jul 2005
The European Network for Diagnostics of Imported Viral Diseases (ENIVD) has presented the results and conclusions of its external quality assurance activities (EQA) carried out in the last five years.
These activities aim at identifying appropriate rapid and sensitive diagnostic tests, essential for the early preparedness and response in the event of viral outbreaks.
The threat posed by emerging and re-emerging communicable diseases is a major concern at national and international levels. Lifestyle changes, migration and above all travel, with 1,600 million air travellers per year, are the main reasons for this unprecedented emergence of infections.
Outbreaks of Ebola haemorrhagic fever in West and Central Africa in recent years, West Nile fever in the United States in 1999 and severe acute respiratory syndrome (SARS) in China in 2002, serve as reminders that severe infections can be imported into Europe by travellers coming from regions with a high incidence and then spread quickly. The import of suspected or confirmed cases of viral haemorrhagic fever (VHF) and SARS reported in the last few years, in different European countries, support these concerns.
Clinicians and clinical microbiology laboratories play an important role in the early detection of disease, the identification of the putative agent, and notification of the appropriate authorities. The improvement of diagnostics of these imported and emerging virus infections is the most important step in detecting the pathogens and dealing with them.
To be effective in this role, laboratories must be specially prepared to handle viral agents safely, and need, among other things, the appropriate rapid and sensitive diagnostic tests to counterbalance the risk of false diagnosis inherent to the difficulty of identifying appropriately unfamiliar symptoms. Furthermore, this possibility increases the risk of disease transmission.
More recently, since the anthrax incidents in the US in 2001 and recent worldwide terror attacks, the authorities have become aware of the need to be prepared for dealing with citizens exposed to or infected with bioterrorism (BT) agents. This preparedness includes the rapid detection and surveillance of putative agents, followed by prompt response and communication.
The early recognition of a bioterrorist event also depends on trained medical and laboratory staff and specific and sensitive laboratory techniques allowing the identification of potential BT agents. As it is impossible to foresee which pathogens might be used by terrorists, it is imperative that efforts for BT preparedness be coordinated with disease surveillance and outbreak response activities. Closer cooperation between global organisations, such as the World Health Organization (WHO), or the European Union and individual countries is also needed.
Because of such emerging problems, and due to the great number of viral pathogens, in the late nineties, it appeared necessary to establish, at European level, a network of collaboration in this field. In 1998, the European Network for Diagnostics of Imported Viral Diseases (ENIVD) was established.
ENIVD fulfils many of the important tasks required for the surveillance and control of imported, rare and emerging viral infections, such as the exchange of expertise and the organisation of external quality assurance (EQA) programmes, both of which are needed to improve diagnostics. Countries with no diagnostic resources of their own can count on the cooperation of expert laboratories for a quick and reliable diagnosis for these kinds of infections.
ENIVID has just presented the results and conclusions of the EQA activities, focused on the diagnostics of infections with hantavirus, dengue virus, filovirus, Lassa virus, orthopox virus and the SARS-coronavirus (SARS-CoV). Carried out between 1999 and 2004, these activities involved 93 laboratories from 41 countries, including laboratories from outside Europe.
Regular quality assurance for diagnostic assays allows the participating laboratories to improve their diagnostic assays, leading to an improvement of the resulting surveillance data for the most common important pathogens such as dengue, or endemic pathogens such as Hanta.
Without this close cooperation within the network, the recent imported VHF cases (Lassa, Netherlands; Yellow Fever, Belgium) would not have been diagnosed as quickly as they were. This significantly reduced the major public concern regarding these threats, which usually arises when speculations regarding unidentified infectious agents are made.
The results of the EQA studies suggest that there is a need to improve many of the assays in order to ameliorate laboratory diagnostic capabilities. Comparative testing of well-characterised samples provides all participating laboratories with the opportunity to examine their weaknesses and improve methodologies.
Several proficiency panels for the EQA of viral diagnostics have been produced for viral pathogens of high prevalence, such as HIV, herpes simplex virus, cytomegalovirus and enteroviruses. These panels are offered throughout Europe by commercial organisations such as the UK NEQAS and INSTAND e.V., or at the initiative of scientific societies such as the European Union Quality Control Concerted Action.
However, and probably due to the fact that these research lines are unlikely to lead to commercially viable products, a number of rare but nevertheless dangerous viral agents are left behind these efforts to improve the reliability and quality of diagnostic output.
To overcome this gap, the ENIVD has begun to generate reference materials for rare viruses that are of public health interest. Samples are available through the ENIVD for the development and validation of diagnostic tests, and the results generated by the participants in the EQA studies will be a valuable resource for others wishing to establish or improve their own tests.
Furthermore, laboratories that require help to improve their diagnostic assays can be supplied with additional diagnostic material or be advised by a competent expert laboratory from the network
For further information, please consult the following web address: