Cystic echinococcosis in slaughtered cattle in Sardinia: a retrospective epidemiological study and spatial analysis.

Cystic echinococcosis (CE) in cattle was found in 246 out of all 377 municipalities in Sardinia, Italy. Out of 32,685 bovines slaughtered in Sardinia in 2009, 1,360 were found to be positive for CE with a registered average prevalence of 4.2%. Of these animals, 896 (66%) had lived on the same farm from birth to slaughter, thus linking the infection to the farm with certainty, while 413 (30%) had lived on two different farms (one transfer) and 51 (4%) on three (two transfers). As it was not possible to assess in which farm the animals acquired the infection, all farms having kept infected cattle were considered as suspected sources of CE infection. Based on this classification, 534 farms were listed as definitely infected with a further 495 suspected to also be infected. Scan statistics was used with the Bernoulli model to detect and evaluate clusters of infected farms and also clusters of "non-cases". For the spatial analysis, 1,029 farms (534 + 495) were considered as positive with the number of non-infected farms from which negative results were available (8,457) as controls. A most likely cluster was detected at latitude 39.47861 N and longitude 8.58216 E in a centroid of 97.92 km radius and a secondary cluster was detected at latitude 40.58890 N and longitude 8.98400 E in a centroid of 15.44 km radius. To address the issue of sensitivity and consistency of the results, we ran multiple scans with various max-sizes as this allowed us to achieve more valid, consistent results and to highlight the core clusters.

Geographic information systems: a useful tool to approach African swine fever surveillance management of wild pig populations.

The epidemiological surveillance of African swine fever in wild pig populations requires the previous collection of numerous samples of biological materials for virological and serological testing from each animal that has been killed during the hunting season. The number of samples needs to demonstrate the absence of the disease at a prevalence level of 5% (and confidence level of 95%) in the area subject observed. Since the typology of the territory suitable for maintaining wild pig populations and the precise location can be identified, it is possible to pinpoint specific areas within Sardinia where organised sampling is undertaken. The results from tests are used to estimate the prevalence of the disease in the wild pig population in the place of origin. Areas were identified using the geographic information system technology with support from maps in the field. The correct localisation of seropositivity has led to the redefinition of high-risk areas for African swine fever. Results from the outbreaks and the surveillance of the wild pig population has confirmed the decreasing role of the wild boar in maintaining the disease.

Use of geographic information systems technology in the epidemiological surveillance of African swine fever.

Geographic information systems (GIS) proved to be very useful during the last two outbreaks of African swine fever in Sardinia and enabled comprehensive the implementation and organisation of the epidemic surveillance system. The knowledge of the precise location of the centre of infection made it possible to characterise all centres of infection and led to the mapping of possible routes of origin and spread of the virus from one case to another. GIS provided valuable and essential information to determine areas that required restrictions and offered an effective model of synergy between epidemiological data and legislative requirements during the epidemic.