Field sampling methods for mosquitoes, sandflies, biting midges and ticks

Abstract

ECDC and EFSA have the mandate to assess the risk of infectious diseases affecting public and animal health and strengthen the capacity for their prevention and control in the EU. Vector-borne diseases, as a specific group of a (re-)emerging infections, pose a threat to European public health and require particular attention. One important aspect of preparedness for vector-borne diseases is the monitoring or surveillance of the introduction, establishment and spread of the main disease vectors. An efficient surveillance or monitoring campaign starts with the development of a well-considered sampling strategy. Depending on the target species, a range of sampling methods is available. This implies that different teams use different approaches and as operational vector sampling methods often lack standardisation, quantitative comparisons across different settings are very hard to make. This also implies that teams starting a disease surveillance project can get overwhelmed by the sheer amount of options and may end up choosing a strategy that is less than ideal to meet their objectives. Although some guidelines exist on the sampling of invasive and native mosquito species in Europe [1–3], there is no summary document on sampling strategies for the various vector species. In the framework of VectorNet, pan-European field campaigns were established to collect data on the presence/absence or seasonal distribution of mosquitoes, sandflies, biting midges and ticks. To standardise the efforts across different teams and to ensure comparable outcomes, a set of protocols were developed for every species group. These protocols describe a uniform way to sample specimens for the four above-mentioned groups. The protocols also describe the conservation of specimens, identification and quality control. Depending on the vector group, the protocols are subdivided according to activity (e.g. flying vs resting mosquitoes and sandflies), life stage (mosquitoes), or species (ticks). Each section describes in detail which traps should be used to meet specific study objectives, how to select a sampling site, when to sample and how long or how often, how to collect the samples, how to preserve them, how to identify them, and how to assess quality.