Tick related diseases in Switzerland, 2008 to 2011.

QUESTION UNDER STUDY: To determine the incidence and determinants of tick related diseases in Switzerland, for example tick bites and Lyme borreliosis in primary care and tick borne encephalitis. METHODS: Analysis of the Swiss data collected by mandatory and facultative surveillance systems for the reporting period of 2008 to 2011. RESULTS: Tick related diseases in Switzerland are common. About 17,000 to 23,000 estimated cases of tick bites lead to a consultation (yearly incidence 254 per 100,000 inhabitants); about 7,000 to 12,000 estimated cases of Lyme borreliosis (yearly incidence 131 per 100,000 inhabitants) and 98 to 172 cases of tick borne encephalitis occur each year (yearly incidence 1.6 per 100,000 inhabitants). The most affected area is the north-eastern part of Switzerland. Whereas cases of tick borne encephalitis are restricted to local endemic areas, cases of Lyme borreliosis and tick bites are spread all over Switzerland. CONCLUSIONS: Tick related diseases are frequent and widespread in Switzerland. They are leading to a considerable usage of the health care system. Thus, tick bite prevention and vaccination against tick borne encephalitis are essential. However, long term follow-up cohort studies with reasonably large study populations after tick bite would be required to elucidate the risk of developing a tick borne disease.

Effects of interventions on the demand for hospital services in an influenza pandemic: a sensitivity analysis.

PRINCIPLES: The evaluation of the capacity of a country's public health system in case of an influenza pandemic is essential for preparedness planning. Only few studies compare existing medical resources with those required during a severe pandemic. METHODS: We perform a sensitivity analysis with the freely available simulation tool InfluSim to explore the expected number of outpatient visits and the hospital bed occupancy in an influenza pandemic in Switzerland. We define plausible ranges for unknown parameter values and take random samples from these ranges. A set of four simulations is run for each parameter constellation, considering no intervention, contact reduction, antiviral treatment or a combination of both interventions. RESULTS: We find that the peak number of outpatient visits of influenza patients would still be manageable by the current number of active physicians with praxis in Switzerland, and that the demand of hospital beds would be only sustainable in the case of a good compliance of the combined interventions. On the other hand, the demand on intensive care unit beds is unsustainably high. CONCLUSIONS: The range of outcomes, resulting from parameter uncertainty, reaches from outpatient and hospitalization values which are half as high as the median to values which double the median. A combination of antiviral treatment and social distancing can considerably mitigate a severe pandemic, but will only bring it under control for the most optimistic parameter constellation combining (mild outbreaks with a high compliance of interventions).