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Host density is an important and widely accepted factor influencing microparasites epidemiology. In theory, host density would influence also macroparasite dynamic, although it would be achieved indirectly due to the presence of free-living infective stages of parasites. On this basis, it is expected that macroparasite abundance and prevalence would increase as host density increases, due to the higher probability for a new host to acquire infections from the environment. Nevertheless, some surveys indicate a negative relationship between host density and gastrointestinal helminth abundance in alpine chamois. On the basis of data collected from three different chamois populations, the Authors discuss the possibility that ecological factors different from host density should influence parasite biocoenosis dynamic, leading to the pattern observed in natural chamois-parasite systems.

A deterministic model considering the population dynamic of chamois and three parasite species (gastrointestinal nematodes) is presented. The model considers the logistic growth of host population, exploitation and/or interference competition among different parasite populations and intraspecific competition between parasite individuals. In vertebrates-parasites systems, intraspecific competition is well known and is probably mediated by host immunity. The sensitivity of the parameter alpha (representing the parasite induced host mortality) and the comparison with field data suggest that intraspecific competition plays an important role in determining host and parasites abundances and in stabilizing chamois-parasites relationship.

During the period 1987-1999, 119 wolf cadavers were examined and checked for the presence of Echinococcus granulosus. All the animals were retrieved along the whole Apennines range of distribution of the species in Italy and most of them were illegally killed. Eighteen wolves resulted positive (15%). The mean intensity was 697.5. The force of infection for prevalence was 8.2 year(-1). The prevalence of the parasite was significantly and positively influenced by the local prevalence of cystic echinococcosis (CE) in sheep. Mean intensity was significantly and positively influenced by both the age of the wolf and the prevalence of CE in sheep. A deterministic model was used in order to simulate a purely theoretical sylvatic cycle of the parasites having the wolf as the only definitive host with 15% of prevalence. The expected prevalence of CE in wild intermediate species ranges between 10% and 25%. This prevalence overlaps the one observed in sheep. Even if both the wolf and the wild ungulate populations are increasing, the wolf still acts as a part of the main dog-sheep cycle of the parasite.

0:74 Escherichia coli epidemic in a Roe deer metapopulation of the Northern Apennines, Italy. An epidemic of enteropathogenic (EPEC) E. coli in a in a free living metapopulation of Roe deer Capreolus capreolus of the Northern Apennines (Italy) is described. 40 out of the 132 censued animals were radiocollared. In the radiocollared animals the infection resulted in a morbility of 12.5% (SD 5.2%), with a lethality of 80% (SD 18%) and the whole mortality reached 10%.(SD 4.7%). The E. coli responsible of the infection was classified as 0:74. The pathological lesions and some clinical features of the infection are described.

It is difficult to determine the part that international trade has played in the expansion of vector-borne diseases, because of the multitude of factors that affect the transformation of habitats and the interfaces between vectors and hosts. The introduction of pathogens through trade in live animals or products of animal origin, as well as the arrival of arthropod vectors, is probably quite frequent but the establishment of an efficient transmission system that develops into a disease outbreak remains the exception. In this paper, based on well-documented examples, the authors review the ecological and epidemiological characteristics of vector-borne diseases that may have been affected in their spread and change of distribution by international trade. In addition, they provide a detailed analysis of the risks associated with specific trade routes and recent expansions of vector populations. Finally, the authors highlight the importance, as well as the challenges, of preventive surveillance and regulation. The need for improved monitoring of vector populations and a readiness to face unpredictable epidemiological events are also emphasised, since this will require rapid reaction, not least in the regulatory context.

From 1987 to 1993, 89 wolves (Canis lupus) collected throughout the whole Italian range were examined for intestinal helminth parasites. Twelve species were found, including 5 nematodes (Uncinaria stenocephala, Toxocara canis, Ancylostoma caninum, Trichuris vulpis and Toxascaris leonina) and 7 cestodes (Echinococcus granulosus, Taenia hydatigena, T. multiceps, T. pisiformis, T. ovis, Mesocestoides lineatus and Dipylidium caninum). No significant differences were detected between sexes. T. canis showed higher prevalence and numbers in youngs, while E. granulosus and T. vulpis in adults. Interference between U. stenocephala and A. caninum was detected. Parasite biocenosis was stable in respect to geographical and ecological variables.

One hundred fifteen samples of wolf (Canis lupus) feces were collected during 1994 to 1995 from four free-living populations of the north central Apennines Mountains, Italy. The samples were tested for canine parvovirus by antigen-capture enzyme-linked immunosorbent assay (ELISA), hemagglutination, and virus isolation. Four of these samples were positive by virus isolation as confirmed by electron microscopy. All positive samples were from Casentino Park in Tuscany. This is the first definitive observation of canine parvovirus in wolves from Europe.

We report the results of a 6-year serological and virological monitoring performed in ducks and coots in Italy, in order to assess the degree of influenza A virus circulation in these birds during wintering. A total of 1039 sera collected from 1992 to 1998 was screened by a double antibody sandwich blocking ELISA (NP-ELISA): seroprevalence of antibodies to influenza A viruses was significantly higher in ducks compared to coots (52.2% vs. 7.1%, respectively). The hemagglutination-inhibition (HI) assay, performed on NP-ELISA positive sera, showed that 16.9% of these duck sera and 33.3% of these coot sera had antibodies to at least one influenza virus HA subtype: ducks showed HI antibodies against most of the HA subtypes, except for the H3, H4, H7, and H12; coots were seropositive to the H3 and H10 subtypes, only. From 1993 to 1998, 22 virus strains were obtained from 802 cloacal swabs, with an overall virus isolation frequency of 2.7%. Viruses belonging to the H1N1 subtype were by far the most commonly circulating strains (18/22) and were isolated mainly from ducks (17/18). The remaining viruses were representative of the H10N8, H5N2 and H3N8 subtypes. Our data indicate some differences between influenza A virus circulation in sympatric ducks and coots and a significant antigenic diversity between some reference strains and viruses recently isolated in Italy.