Table 2. Summary of the main characteristics, advantages, limitations and requirements of the six proposed scenarios for surveillance of Lyme borreliosis across the European Union/European Economic Area.
| Surveillance Scenario | Key indicator for surveillance | Who is reporting | Advantages | Limitations | Requirements |
|---|---|---|---|---|---|
| 1 | Erythema migrans | Hospital physicians/GPs | - Relatively easy recognised and diagnosed, without the need for laboratory confirmation. - Most common manifestation of early LB. - More information on neuroborreliosis multiplication factora. |
- Motivation to report may be low for this mild condition. - Probability of clinically diagnosing EM may differ between low- and high-incidence countries or regions. - In some countries GP/other physicians’ catchment populations may be difficult to achieve or estimate. |
- In each country GPs/other physicians should be reached and motivated to report EM cases. - Accurate administrations of the names and addresses of GPs/other physicians would facilitate this process. - Communication campaigns can be launched by national or regional public health officials. - In case of not comprehensive surveillance, for each reporting GP/physician their catchment population needs to be known (or estimated) to be able to calculate accurate incidence rates. |
| 2 | Neuroborreliosis | Laboratories Hospital physicians/GPs |
- Precise and standardised case definition possible, building upon the EFNS guidelines [22]. - One of the most frequent manifestations of disseminated LB, and because of its severity possibly less susceptible to under-reporting. - In some countries reporting based on laboratory information systems may even further reduce under-reporting. |
- Laboratory diagnostics on CSF not standard in all countries. - Little data on multiplication factor to other manifestations, which may differ between countries because of the heterogeneous distribution of Borrelia genospecies [2-4,22]. - Less sensitive to trends in time than EM because of its lower occurrence rate. |
- National and regional laboratories and/or GPs/other physicians should be able to report cases based upon standardised case definitions. - In case of not comprehensive surveillance, the catchment population of the reporting entities must be known and representative of the total population. - Starting by one or a few central laboratories per country may be sufficient to have standardised and comparable data between countries. |
| 3 | All LB manifestations | Laboratories, hospital physicians/GPs |
- Incidence estimated for the complete spectrum of LB. - Complete information on neuroborreliosis multiplication factor. - Will facilitate assessment of the disease burden of LB in DALYs (e.g. healthy life-years lost), to allow policymakers to compare the impact of LB with other (infectious) diseases [11,31]. |
- Surveillance of all LB manifestations will have a huge reporting burden. For countries with a high incidence of LB, notification of all cases will not be feasible because the workload would be too high for physicians - Diagnosing the disseminated manifestations of LB (other than neuroborreliosis) can be complicated, resulting in a high risk of inconsistencies (and a risk of lack of specificity) in surveillance data. - Standardisation of all LB manifestations might be difficult. - Cumbersomeness of assessing all laboratory and clinical criteria per patient may result in under-reporting. - High costs will be involved in training of personnel, and extensive quality control would be needed to guarantee representativeness and compatibility between countries. |
- In each country GPs/other physicians, complemented by national and regional laboratories, should be reached and motivated to report all LB cases. - Accurate administrations of the names and addresses of GPs/other physicians would facilitate this process. - Communication campaigns can be launched by national or regional public-health officials. - In case of not comprehensive surveillance, for each reporting GP/other physician their catchment population needs to be known (or estimated) to be able to calculate accurate incidence rates. |
| 4 | Seroprevalence | Population-based studies, laboratories, GPs |
- No under-reporting because seroprevalence studies are not dependent on reporting by other entities than laboratories. - Standardisation of laboratory criteria possible in a prospective setting. - Seroprevalence studies provide additional epidemiological data, such as information on risk factors and spatial patterns that can be used to complement data from other notification systems [17,28]. |
- Only seroprevalence (historical exposure) can be measured, and no data on the incidence of LB (active infection) can be derived. - Neither new cases that have emerged recently nor the real disease burden can be assessed through such studies [27]. - In a prospective setting, a complete and representative sampling for this purpose can be expensive. - Different serological tests are available targeting different antibodies and having different sensitivities and specificities. Standardisation among countries is needed if inter-country comparisons is aimed for. |
- Careful design of a seroprevalence study is required to obtain a representative sample of all regions of the country. - There is the need to clearly define and standardise the laboratory methodology and criteria across countries for comparability. |
| 5 | Tick bites | General public | - Hotspots of human exposure to tick bites can be detected with relatively high sensitivity, which can be used to steer regional intervention strategies. - National and regional communication campaigns will improve awareness of the public and physicians of LB. - Characteristics of hotspots can also be compared between countries, and be used as input in a knowledge-based European risk map. |
- Awareness and education of the public is needed to generate a sufficient report rate of tick bites. - The number of tick bite reports over time will be influenced by media attention and thus not always accurately reflect temporal trends of tick bites or LB. - Media attention for online reporting of tick bites will differ between countries, which will complicate quantitative comparison between countries. |
- Public awareness of the risk for LB is needed as a motivation to report tick bites, which requires national and regional media campaigns to inform the public about online reporting. - Communication of the results is needed to inform and motivate the participants. |
| 6 | Tick or reservoir hosts Borrelia prevalence | Research groups | - Complementary to human LB surveillance. - Results would improve the prospective surveillance of LB by providing more insight on the ecological and epidemiological features of LB. - Periodic research studies are already standard in many countries. |
- It is a complicated process to timely collect catchment data with substantial coverage in a relatively standardised manner. - Data on the tick/reservoir Borrelia prevalence is not necessarily associated with the number of LB cases in humans. - Newly invaded tick areas may be missed. These possibly contribute more to increased tick bite risk than established catchment areas and will have a different temporal trend. |
- A European network is needed to standardise sampling and collection protocols and to gather national catchment data on ticks and reservoirs from the national and regional networks that already perform such surveillance. - VectorNetb could possibly facilitate future integration and comparison of these data [33]. - It has already been shown that based on the currently available data in published literature space and time trends of infected tick can be assessed. |
DALY: disability-adjusted life year; EFNS: European Federation of Neurological Societies; EM: erythema migrans; GP: general practitioner; LB: Lyme borreliosis.
a The factor (or factors) permitting estimation of the incidence of all LB manifestations based on surveillance data from another LB manifestation, e.g. estimate the incidence of neuroborreliosis based upon the incidence of EM.
b VectorNet is a joint initiative of the European Food Safety Authority (EFSA) and the European Centre for Disease Prevention and Control (ECDC). The project supports the collection of data on vectors related to both animal and human health in Europe and the Mediterranean basin: http://ecdc.europa.eu/en/healthtopics/vectors/VectorNet/Pages/VectorNet.aspx