impaginato piccolo - Società Italiana di Parassitologia (SoIPa)

other EU countries, yet the impact of this pathogen on
human health in Europe is unknown. In animals, which
are the only reservoir of this parasite in Europe, the
infection is widespread in cattle, sheep and goats, yet
the prevalence greatly varies by type of breeding, characteristics
of the habitat, and climate.
Anisakidae
In Europe, anisakiasis mainly occurs in Western countries,
where there is a higher consumption of sea fish.
Approximately 2,000 cases have been documented in
Europe, mostly in France, the Netherlands, and Spain
(Bouree et al., 1995; Smith, 1999; Audicata et al.,
2002), although dozens of cases have been also documented
in Belgium, Italy, and the United Kingdom
(Mattiucci et al., 2007). In the last years, there has
been a marked increase in prevalence, probably
because of the use of new diagnostic techniques, in particular,
endoscopy. However, the increase in prevalence
is probably also related to two other factors: i) the
growing preference for raw or lightly cooked seafood;
and ii) the increasing population size of potential definitive
hosts, although this second factor should be
proved with more convincing data, since the published
results are contrasting. A very large number of fish and
cephalopod species act as hosts for Anisakis spp. (200
fish and 25 cephalopod species) and Pseudoterranova
(75 fish species in the North Atlantic only), and the
global market easily allows that infected fish originating
from far sea are consumed in EU few hours after
fishing.
Trichinella
In Europe, the source of human trichinellosis varies by
country. In the original 15 EU countries, in the past 30
years only in France, Germany, Italy and Spain, human
infections for the consumption of autochthonous
domestic and/or wild animals have been reported
(Pozio, 2007). In the new Member States, outbreaks of
trichinellosis for the consumption of local animals have
occurred in Bulgaria, Estonia, Latvia, Lithuania,
Poland, Romania, and the Slovak Republic (Pozio,
2007). Today in Western Europe, there are increasingly
reports of trichinellosis among immigrants from
Eastern countries, who acquire the infection in the
country of origin. The most prevalent species is
Trichinella britovi, which has been detected in all countries
but Cyprus, Denmark, Ireland, Luxembourg,
Malta, and the UK (Pozio, 2007). The second most
prevalent species is T. spiralis, which circulates prevalently
among wild boars and domestic pigs. T. britovi is
more widespread than T. spiralis in sylvatic carnivores
(89% vs. 11%), whereas T. spiralis is more widespread
than T. britovi in both sylvatic swine (62% vs. 38%)
and domestic swine (82% vs. 18%) and in rodents
(75% vs. 25%). Trichinella nativa is restricted to carnivorous
mammals of countries of the Scandinavian
peninsula and Estonia, and seldom it has been documented
in Latvia and Lithuania (Pozio, 2007).
Trichinella pseudospiralis shows a sporadic distribution
in sylvatic animals of Bulgaria, Denmark, France,
E. Pozio - Foodborne parasitic zoonoses
Finland, Germany, Hungary, Italy, and Sweden, though
infections have also been documented in domestic pigs
and synanthropic rats of the Slovak Republic (Pozio and
Murrell, 2006; www.iss.it/site/Trichinella/index.asp).
Control prospects
21
This brief review shows the broad spectrum of foodborne
parasitic zoonoses circulating in EU countries
and the prevalence of these zoonoses in humans.
However, from a practical standpoint, the control
strategies that have been developed in Europe are limited
and only concern a few of the pathogens, whereas
most of them are not subject to any form or control or
there are only control regulations in some Member
States. Furthermore, most of the diseases induced by
these pathogens are not subject to mandatory notification
or are subject to mandatory notification in some
countries only.
In general, very little attention has been placed on the
epidemiology of foodborne parasitic zoonoses caused
by protozoa. One of the main causes of this indifference
is probably the lack of an inexpensive, rapid, and
simple method for detecting animals infected with
these pathogens which can be used at the slaughterhouse.
None of the zoonotic protozoa is subject to controls in
livestock, at the farm or slaughterhouse, or in derived
food products during their processing. Only in some
EU countries (e.g., Denmark, Germany, the
Netherlands, Sweden, and the UK), the detection of
Cryptosporidium sp. in humans or in water resources
should be notified to regional health authorities, yet
never if the parasite is detected in animals. However,
there has been increasing interest in T. gondii, because
of its pathogenicity to both humans and animals and
for the economic loss resulting from abortions in sheep,
goats and pigs. To this regard, initial attempts have
been made to produce Toxoplasma-free pigs (e.g., in
Denmark and the Netherlands), although the type of
pigsty that should be built to avoid contamination of
the pigsty environment with T. gondii oocysts shed by
cats entails breeding the pigs indoors for the entire
breeding period, which is in contrast with the new regulations
on animal welfare, which require that pigs
have outdoor access.
The control of zoonotic parasitic infections in both saltwater
and freshwater fish only consists of visually
examining few fish from each stock at the fish market
by the veterinary services. Only in few cases, the muscle
tissues of fish are tested by candling. Evidently, this
control approach cannot prevent infected fish from
reaching the consumer. Thus preventive measures can
only be based on consumer education and to appropriately
frozen fish which should be consumed raw (at
least -20 in the core of the fish product for at least 52
hours); smoking and marination are insufficient. Dry
salting can be successfully used, providing that the salt
reaches all of the edible parts of the fish in concentrated
form, but it is difficult to establish a protocol.
In livestock, most of the zoonotic parasites (e.g.,