Spatio-temporal optimization of sampling for bluetongue vectors (<em>Culicoides</em>) near grazing livestock

BACKGROUND: Estimating the abundance of Culicoides using light traps is influenced by a large variation in abundance in time and place. This study investigates the optimal trapping strategy to estimate the abundance or presence/absence of Culicoides on a field with grazing animals. We used 45 light traps to sample specimens from the Culicoides obsoletus species complex on a 14 hectare field during 16 nights in 2009. FINDINGS: The large number of traps and catch nights enabled us to simulate a series of samples consisting of different numbers of traps (1-15) on each night. We also varied the number of catch nights when simulating the sampling, and sampled with increasing minimum distances between traps. We used resampling to generate a distribution of different mean and median abundance in each sample. Finally, we used the hypergeometric distribution to estimate the probability of falsely detecting absence of vectors on the field. The variation in the estimated abundance decreased steeply when using up to six traps, and was less pronounced when using more traps, although no clear cutoff was found. CONCLUSIONS: Despite spatial clustering in vector abundance, we found no effect of increasing the distance between traps. We found that 18 traps were generally required to reach 90% probability of a true positive catch when sampling just one night. But when sampling over two nights the same probability level was obtained with just three traps per night. The results are useful for the design of vector monitoring programmes on fields with grazing animals

Quantifying the potential for bluetongue virus transmission in Danish cattle farms

We used a mechanistic transmission model to estimate the number of infectious bites (IBs) generated per bluetongue virus (BTV) infected host (cattle) using estimated hourly microclimatic temperatures at 22,004 Danish cattle farms for the period 2000–2016, and Culicoides midge abundance based on 1,453 light-trap collections during 2007–2016. We used a range of published estimates of the duration of the hosts’ infectious period and equations for the relationship between temperature and four key transmission parameters: extrinsic incubation period, daily vector survival rate, daily vector biting rate and host-to-vector transmission rate resulting in 147,456 combinations of daily IBs. More than 82% combinations of the parameter values predicted > 1 IBs per host. The mean IBs (10–90th percentiles) for BTV per infectious host were 59 (0–73) during the transmission period. We estimated a maximum of 14,954 IBs per infectious host at some farms, while a best-case scenario suggested transmission was never possible at some farms. The use of different equations for the vector survival rate and host-to-vector transmission rates resulted in large uncertainty in the predictions. If BTV is introduced in Denmark, local transmission is very likely to occur. Vectors infected as late as mid-September (early autumn) can successfully transmit BTV to a new host until mid-November (late autumn)

Quantifying Dispersal of European Culicoides (Diptera: Ceratopogonidae) Vectors between Farms Using a Novel Mark-Release-Recapture Technique

Studying the dispersal of small flying insects such as Culicoides constitutes a great challenge due to huge population sizes and lack of a method to efficiently mark and objectively detect many specimens at a time. We here describe a novel mark-release-recapture method for Culicoides in the field using fluorescein isothiocyanate (FITC) as marking agent without anaesthesia. Using a plate scanner, this detection technique can be used to analyse thousands of individual Culicoides specimens per day at a reasonable cost. We marked and released an estimated 853 specimens of the Pulicaris group and 607 specimens of the Obsoletus group on a cattle farm in Denmark. An estimated 9,090 (8,918-9,260) Obsoletus group specimens and 14,272 (14,194-14,448) Pulicaris group specimens were captured in the surroundings and subsequently analysed. Two (0.3%) Obsoletus group specimens and 28 (4.6%) Pulicaris group specimens were recaptured. The two recaptured Obsoletus group specimens were caught at the release point on the night following release. Eight (29%) of the recaptured Pulicaris group specimens were caught at a pig farm 1,750 m upwind from the release point. Five of these were recaptured on the night following release and the three other were recaptured on the second night after release. This is the first time that movement of Culicoides vectors between farms in Europe has been directly quantified. The findings suggest an extensive and rapid exchange of disease vectors between farms. Rapid movement of vectors between neighboring farms may explain the the high rate of spatial spread of Schmallenberg and bluetongue virus (BTV) in northern Europe

Bluetongue Virus Serotype 1 Outbreak in the Basque Country (Northern Spain) 2007–2008. Data Support a Primary Vector Windborne Transport

BACKGROUND: Bluetongue (BT) is a vector-borne disease of ruminants that has expanded its traditional global distribution in the last decade. Recently, BTV-1 emerged in Southern Spain and caused several outbreaks in livestock reaching the north of the country. The aim of this paper was to review the emergence of BTV-1 in the Basque Country (Northern Spain) during 2007 and 2008 analyzing the possibility that infected Culicoides were introduced into Basque Country by winds from the infected areas of Southern Spain. METHODOLOGY/PRINCIPAL FINDINGS: We use a complex HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory) model to draw wind roses and backward wind trajectories. The analysis of winds showed September 28 to October 2 as the only period for the introduction of infected midges in the Basque Country. These wind trajectories crossed through the areas affected by serotype 1 on those dates in the South of the Iberian Peninsula. Additionally meteorological data, including wind speed and humidity, and altitude along the trajectories showed suitable conditions for Culicoides survival and dispersion. CONCLUSIONS/SIGNIFICANCE: An active infection in medium-long distance regions, wind with suitable speed, altitude and trajectory, and appropriate weather can lead to outbreaks of BTV-1 by transport of Culicoides imicola, not only over the sea (as reported previously) but also over the land. This shows that an additional factor has to be taken into account for the control of the disease which is currently essentially based on the assumption that midges will only spread the virus in a series of short hops. Moreover, the epidemiological and serological data cannot rule out the involvement of other Culicoides species in the spread of the infection, especially at a local level

Neemagrimed: una “Best Practice” in agricoltura biologica.

Il neem cake, scarto del processo estrattivo dei semi di neem, è un prodotto dalle straordinarie potenzialità. La partnership del progetto “Neemagrimed”, premiato come “Best Practice” di agricoltura biologica ad EXPO 2015, ha sviluppato studi e ricerche per validare l’efficacia del prodotto come insetticida, fertilizzante e nematocida in alternativa a prodotti non più autorizzati dalle normative europee. La divulgazione dei risultati ottenuti ha permesso il trasferimento e la diffusione dell’uso del prodotto tra i coltivatori e gli allevatori biologici e tradizionali. La validazione e la promozione del riuso, di uno scarto industriale, implicano l’innovazione e l’efficientamento della intera filiera produttiva

SCREENING FOR TICK-BORNE AND TICK-ASSOCIATED VIRUSES IN TICKS COLLECTED IN SARDINIA, ITALY

Ticks are important vectors of many pathogens, including arboviruses also known as tickborne viruses (TBVs). Climate changes are promoting ticks and TBVs spread with the diffusion of new pathogens, as the CCHFV that in the last decade colonized the Southwest Europe, as indicated by human cases reported in Spain and the evidence of virus circulation in animals of Corsica (France). Sardinia is an Italian island close to Corsica, it is a site of intense passage of birds migrating along major routes between Africa and Europe, thus representing a site potentially exposed to the risk for introduction of CCHFV or other TBVs. This study was designed to determine the presence of TBVs and/or tick-associated viruses in ticks collected in Sardinia. A total of 217 ticks were collected from different districts belonging to the north western, south-west and central Sardinia, all areas are of great naturalistic importance and show a wide diversity in geology, vegetation, landscape features and agro-ecology. Ticks were collected from domestic animals, wild mammals, and vegetation. Three ticks were also collected from human. Morphological identification of ticks was performed by taxonomic keys. Each sample was longitudinally incised, and only one half of tick was homogenated by mechanical tissue lyser. Nucleic acids were extracted with (Promega). One aliquote was subject to one-step real-time RT-PCR for the detection of CCHFV, using AgPath-ID One-Step RT-PCR Kit (Thermo Scientific). Each sample was also tested for nairoviruses, phleboviruses and flaviviruses using a Pan-PCR approach. Preliminary results did not show the presence of CCHFV while the Pan-PCR-based screening is still ongoing and results will be presented

Daily peer review of abnormal cervical smears in the assessment of individual practice as an additional method of internal quality control

An important internal quality control system used in the Cancer Prevention and Research Institute cytopathology laboratory in Florence is the peer review procedure, based on the review of all abnormal cytological smears which routinely emerge. Peer review is an important training opportunity for all cytologists, especially for those with less experience. This article shows the results of the peer review procedure