Trichinella in pork: current knowledge on the suitability of freezing as a public health measure.
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Animals↗
Biomedical subjects
E Pozio
Publications and source records attributed to E Pozio.
Post-Miocene expansion, colonization, and host switching drove speciation among extant nematodes of the archaic genus Trichinella.
Parasitic nematodes of the genus Trichinella cause significant food-borne illness and occupy a unique evolutionary position at the base of the phylum Nematoda, unlike the free-living nematode Caenorhabditis elegans. Although the forthcoming genome sequence of Trichinella spiralis can provide invaluable comparative information about nematode biology, a basic framework for understanding the history of the genus Trichinella is needed to maximize its utility. We therefore developed the first robust and comprehensive analysis of the phylogeny and biogeographic history of Trichinella using the variation in three genes (nuclear small-subunit rDNA, and second internal transcribed spacer, mitochondrial large-subunit rDNA, and cytochrome oxidase I DNA) from all 11 recognized taxa. We conclude that (i) although Trichinellidae may have diverged from their closest extant relatives during the Paleozoic, all contemporary species of Trichinella diversified within the last 20 million years through geographic colonization and pervasive host switching among foraging guilds of obligate carnivores; (ii) mammalian carnivores disseminated encapsulated forms from Eurasia to Africa during the late Miocene and Pliocene, and to the Nearctic across the Bering Land Bridge during the Pliocene and Pleistocene, when crown species ultimately diversified; (iii) the greatest risk to human health is posed by those species retaining an ancestral capacity to parasitize a wide range of hosts; and (iv) early hominids may have first acquired Trichinella on the African savannah several million years before swine domestication as their diets shifted from herbivory to facultative carnivory.
Animals↗
Epidemiological investigations on Trichinella infections in farmed fur animals of Estonia.
Farming of fur animals represents an important income in Estonia. Even though Trichinella worms does not induce a symptomatic disease in carnivores, the carcasses of skinned animals can increase the biomass of the parasite in the environment, if they are not properly destroyed. The aim of the present survey was to study the prevalence of Trichinella worms in farmed fur animals of Estonia. Of 281 muscle samples from blue foxes (Alopex lagopus), silver foxes (Vulpes vulpes fulva), minks (Mustela vison) and raccoon dogs (Nyctereutes procyonoides), which were collected in eight farms, Trichinella larvae have been detected in 21 animals (8%) from two farms by HCl-pepsin digestion. The highest number of larvae per gram of muscle was found in the front limb muscles. Larvae of the 21 isolates have been identified as Trichinella britovi or Trichinella nativa by a multiplex-PCR analysis.
Animals↗
Trichinella spiralis and Trichinella pseudospiralis mixed infection in a wild boar (Sus scrofa) of Germany.
A wild boar (Sus scrofa) from the island Usedom in Mecklenburg-Western Pomerania (north-east Germany) was detected as Trichinella-positive during routine meat inspection. Encapsulated and non-encapsulated larvae were detected in the muscle tissue by trichinoscopy. In the diaphragm, 922 larvae per g were detected by artificial digestion. Muscle larvae displayed two different sizes of about 700 and 1100 microm. By a multiplex PCR analysis, larvae with a large size were identified as Trichinella spiralis, whereas those of a smaller size were identified as Trichinella pseudospiralis. This is the first finding of a mixed infection of T. spiralis and T. pseudospiralis in a naturally infected animal and it supports the tendency of more frequent detection of the non-encapsulated species T. pseudospiralis in Europe.
Abattoirs↗
Clinical and laboratory aspects of a trichinellosis outbreak in Izmir, Turkey.
Epidemiological, clinical and laboratory data were collected during an outbreak of trichinellosis, which occurred in Izmir, Turkey, between January and March 2004. The source of the infection was raw meatballs made with a mixture of uncooked beef and pork. Of 474 persons who were admitted at the Ataturk Training and Research Hospital during this period with a history of raw meatball consumption, the diagnosis of trichinellosis was confirmed for 154 (32.5%, 87 males and 67 females; mean age 31 years, range 6-67 years). Among persons with a confirmed diagnosis, 79% had myalgia, 77% weakness and malaise, 63% arthralgia, 40% jaw pain, 68% fever, 63% periorbital and/or facial oedema, 49% oedema at the trunk and limb, 42% abdominal pain, 40% nausea and vomiting, 28% diarrhoea, 23% subconjunctival haemorrhage, 25% macular or petechial rash, 4% subungual haemorrhage, 15% cardiac complaints and 0.2% neurological complaints. Nine patients (5.8%) were hospitalised due to severe myalgia (n = 2), high fever (n = 3), neurological manifestations (n = 1), thrombophlebitis (n = 2) and palmar erythema (n = 1). Eosinophilia was present in 88% of the confirmed cases at the admission. Elevated levels of serum creatine phosphokinase, lactic dehydrogenase and aspartate aminotransferase were detected in 72%, 70% and 16% of the confirmed cases, respectively. The seroconversion occurred in most of the infected people between the 4th and 6th weeks after the infection. All of the confirmed cases were treated with mebendazole. People with severe symptoms were treated also with prednisolone (60 mg/day for three days) and those with a moderately severe clinical pattern received a non-steroid anti-inflammatory drug (naproxen sodium, 550 mg/day). All confirmed cases recovered without any clinical sequela.
Adolescent↗
Meat inspection for Trichinella in pork, horsemeat and game within the EU: available technology and its present implementation.
A new EU directive relating to meat inspection for Trichinella, expected to come into force in 2006, imposes important modifications to current legislation. Nevertheless, several issues need more attention. Optimisation of methods, especially concerning sensitivity and digestibility of the meat to be inspected, along with further simplification of the legislation with regard to the number of techniques accepted, is recommended to guarantee that all member states of the EU will be given tools to perform inspection of consumer meat at the same high level. Additionally, there is a need for guidelines and protocols regarding optimal proficiency testing procedures. This paper presents an overview of the current methods for Trichinella meat inspection and their implementation in the EU, listing advantages and disadvantages for each method, including some suggestions for specific points of improvement.
Animals↗
[First report of a human case of trichinellosis due to Trichinella britovi after jackal (Canis aureus) meat consumption in Algeria].
We report a single case of trichinellosis contracted in Algeria (Batna region), in a practising Moslim. Shortly after returning to France in November 2004, the patient developed the typical clinical and biological signs of the disease. Although the patient claimed having only eaten mutton, an unusual host for Trichinella, a meticulous investigation revealed that he also had eaten a grilled leg of jackal (Canis aureus). One of the four Trichinella larvae detected in a muscular biopsy enabled us to identify the parasite as Trichinella britovi by a multiplex PCR analysis. This is the first identification of the etiological agent of sylvatic trichinellosis occurring in North Africa and the first case of symptomatic trichinellosis due to jackal meat consumption in Africa.
Aged↗
Echinococcus multilocularis in north Italy.
Alveolar echinococcosis is a zoonotic infection caused by the metacestode of the tapeworm Echinococcus multilocularis. Fox populations living in the Alpine regions of Italy had been considered free from this parasite until 2002, when two infected foxes were detected in Bolzano province (Trentino Alto Adige region) near Austrian border. A modified nested PCR analysis was used to detect E. multilocularis DNA in faecal samples belonging to red fox populations from five Italian regions. A total of 522 faecal samples were analysed from foxes shot in Valle d'Aosta (N = 65), Liguria (N = 44), Lombardy (N = 105), Veneto (N = 67), and Trentino Alto Adige (N = 241) regions. Among these, 24 samples, all from the Trentino Alto Adige region, were found positive. Moreoever, 1406 faecal samples of red foxes were analyzed by CA-ELISAs commercial test kit. This paper provides an update of the epidemiological knowledge of this parasite in north Italy.
Animals↗
Apicomplexa genes involved in the host cell invasion: the Cpa135 protein family.
The availability of a bulk of genomic data of Apicomplexa parasites is a unique opportunity to identify groups of related proteins that are characteristic of this phylum. The Cpa135 protein of Cryptosporidium parvum is expressed and secreted through the apical complex at the invasive stage of sporozoite. This protein is characterised by an LCCL domain, a common trait of various secreted proteins within Apicomplexa. Using the Cpa135 as a "virtual template", we have identified Cpa135 orthologous genes in four apicomplexan species (Plasmodium falciparum, Theileria parva, Toxoplasma gondii and Eimeria tenella). In addition, the architecture of the deduced proteins shows that the Cpa135-related proteins are a distinct family among the apicomplexan LCCL proteins.
Animals↗
Serodiagnosis of trichinellosis: in-house versus commercial ELISA.
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Adult↗
First isolation of Trichinella britovi from a wild boar (Sus scrofa) in Belgium.
Since 1992, when the European Union Council Directive requires that wild boars (Sus scrofa) hunted in EU for commercial purpose should be examined for Trichinella, the infection has not been detected in wild boars from Belgium, despite serological evidence of the presence of anti-Trichinella antibodies in wildlife and previous reports of Trichinella larvae in this host species. In November 2004, Trichinella larvae were detected in a wild boar hunted near Mettet, Namur province (Southern Belgium). Larvae were identified as Trichinella britovi by polymerase chain reaction methods. This is the first report of the identification of Trichinella larvae from Belgium at the species level. The detection of T. britovi in wildlife in Belgium is consistent with findings of this parasite in other European countries and confirms the need to test game meat for Trichinella to prevent its transmission to humans.
Animals↗
The broad spectrum of Trichinella hosts: from cold- to warm-blooded animals.
In recent years, studies on Trichinella have shown that the host range is wider than previously believed and new Trichinella species and genotypes have been described. Three classes of vertebrates are known to act as hosts, mammals, birds and reptiles, and infected vertebrates have been detected on all continents but Antarctica. Mammals represent the most important hosts and all Trichinella species are able to develop in this vertebrate class. Natural infections with Trichinella have been described in more than 150 mammalian species belonging to 12 orders (i.e., Marsupialia, Insectivora, Edentata, Chiroptera, Lagomorpha, Rodentia, Cetacea, Carnivora, Perissodactyla, Artiodactyla, Tylopoda and Primates). The epidemiology of the infection greatly varies by species relative to characteristics, such as diet, life span, distribution, behaviour, and relationships with humans. The non-encapsulated species Trichinella pseudospiralis, detected in both mammals (14 species) and birds (13 species), shows a cosmopolitan distribution with three distinguishable populations in the Palearctic, Nearctic and Australian regions. Two additional non-encapsulated species, Trichinella papuae, detected in wild pigs and saltwater crocodiles of Papua New Guinea, and Trichinella zimbabwensis, detected in farmed Nile crocodiles of Zimbabwe, can complete their life cycle in both mammals and reptiles. To the best of our knowledge, T. papuae and T. zimbabwensis are the only two parasites known to complete their entire life cycle independently of whether the host is warm-blooded or cold-blooded. This suggests that these two Trichinella species are capable of activating different physiological mechanisms, according to the specific vertebrate class hosting them.
Animals↗
Experimental studies in pigs on Trichinella detection in different diagnostic matrices.
A total of 72 specific pathogen-free (SPF) and Iberian pigs (three animals per group) were inoculated with 200, 1000 or 20,000 muscle larvae of T. spiralis, T. nativa, T. britovi and T. pseudospiralis. For each animal, the muscle larva burden was evaluated in nine muscle samples by digestion. The anti-Trichinella IgG kinetics in blood samples, taken twice prior and at days 5, 10, 15, 20, 25, 30, 40, 50 and 60 post-inoculation, and in muscle juice, obtained at necropsy, was evaluated by an ELISA using an excretory/secretory antigen. The mean larval recovery rate in SPF/Iberian pigs corresponded with the level of inoculum dose, and tongue, diaphragm and masseter were identified as predilection muscles. In SPF and Iberian pigs receiving 20,000 larvae of T. spiralis, an earlier seroconversion was detected from day 25 post-inoculation. At a 10-fold dilution, the muscle juice showed a good test agreement with blood serum.
Animals↗
Evaluation of the infectivity of Trichinella papuae and Trichinella zimbabwensis for equatorial freshwater fishes.
The discovery of Trichinella species infecting poikilotherm vertebrates has opened new possibilities in the epidemiology of this parasite group. The aim of the present work was to investigate the infectivity of the two non-encapsulated species of Trichinella infecting both mammals and reptiles, Trichinella papuae and Trichinella zimbabwensis, for equatorial freshwater carnivore fishes. To this end, two species of piranhas, four Serrasalmus nattereri and four Serrasalmus rhombeus, were each inoculated per os with the two species of Trichinella larvae. Six days post infection (p.i.), one fish of each species inoculated with one of the two species of Trichinella was sacrificed. The intestines and celomatic cavities were searched for worms using dissection microscopy, and the presence of muscle larvae was evaluated by artificial digestion. The other 4 inoculated fish were sacrificed 60 days p.i. and similarly searched for the presence of worms. No larva or adult worms were detected in any organ or tissue at 6 or 60 days p.i. The lack of infectivity of T. papuae and T. zimbabwensis for fish suggests that the entozoic habitat of this animal does not represent a suitable environment for these two Trichinella species. More importantly, these data indicate that freshwater fishes, one of the food resources for crocodiles, caimans and alligators, are unlikely to play a role in the epidemiology of the known species of the genus Trichinella.
Animals↗
Trichinella pseudospiralis from a wild pig in Texas.
In December 2001, the routine inspection of a wild boar intended for human consumption revealed the presence of Trichinella ssp. larvae. Biological, morphological and genetic analyses demonstrated the parasite to be Trichinella pseudospiralis. This is the second report of T. pseudospiralis in the United States and the first report of the parasite in a food animal species in the U.S.
Animals↗
Phylogenetic analysis of encapsulated and non-encapsulated Trichinella species by studying the 5S rDNA tandemly repeated intergenic region.
The identification of sequence regions in the genomes of pathogens which can be useful to distinguish among species and genotypes, is of great importance for epidemiological, molecular, and phylogenetic studies. The 5S ribosomal DNA intergenic spacer region has been identified as a good target to distinguish among eight Trichinella species and genotypes. The recent discovery of two non-encapsulated species in this genus, Trichinella papuae and Trichinella zimbabwensis, which can infect both mammals and reptiles, has suggested analyzing their 5S rDNA. Amplification of the tandem repeats of the 5S rDNA intergenic region of encapsulated species of Trichinella shows a 751bp fragment, whereas the three non-encapsulated species show a fragment of 800bp with T. pseudospiralis showing an additional fragment of 522bp. Although the size of the 800bp PCR fragments of T. papuae and T. zimbabwensis are similar to that of T. pseudospiralis, there are differences in the 5S rDNA intergenic regions among the three non-encapsulated species. Phylogenetic analysis of the 5S rDNA intergenic regions shows a clustering together of the three non-encapsulated Trichinella species that is well separated from the encapsulated ones. In addition, a single PCR-based method allows distinguishing non-encapsulated and encapsulated species.
Animals↗
Trichinella britovi etiological agent of sylvatic trichinellosis in the Republic of Guinea (West Africa) and a re-evaluation of geographical distribution for encapsulated species in Africa.
In West Africa, Trichinella infection was documented in humans and animals from Senegal in the 1960s, and the biological characters of one isolate showed a lower infectivity to domestic pigs and rodents when compared with that of a Trichinella spiralis pig isolate from Europe. To identify the Trichinella species present in West Africa, a survey was conducted in a total of 160 wild animals in the Republic of Guinea. Three Viverridae, one true civet (Viverra civetta) and two African palm civets (Nandinia binotata) from the Fouta Djallon Massif, Pilimini Subprefecture, were found positive by artificial digestion of muscle samples. Trichinella larvae from these three viverrids were identified as Trichinella britovi and no difference was detected in three examined sequences from these African isolates and the reference strain of T. britovi from Europe, indicating common ancestry, an historically continuous geographic distribution, and recent isolation for African and European populations. The detection of T. britovi in West Africa modifies our knowledge about the distribution of encapsulated species of Trichinella in Africa. Thus, Trichinella nelsoni is now considered to have a distribution limited to the Eastern part of the Afrotropical region from Kenya to South Africa. This provides a plausible explanation for the presence of Trichinella T8 in Namibia and South Africa, and further suggests that T. britovi could be the Trichinella species circulating among wild animals of Northern Africa.
Animals↗
Echinococcus multilocularis in red foxes (Vulpes vulpes) of the Italian Alpine region: is there a focus of autochthonous transmission?
Alveolar echinococcosis, caused by the metacestode of Echinococcus multilocularis, is a zoonosis with a wider distribution area than described in the past. Fox populations living in the Alpine regions of Italy had been considered free from this parasite until 2002, when two infected foxes (Vulpes vulpes) were detected in the Bolzano province (Trentino Alto Adige region) near the Austrian border. The aim of this work was to evaluate the prevalence of infection in red fox populations from five Italian regions. A modified nested PCR analysis was used to detect E. multilocularis DNA in faecal samples. Amplicons were confirmed by sequencing. Of 500 faecal samples from foxes shot in Valle d'Aosta (n=57), Liguria (n=44), Lombardy (n=102), Veneto (n=56), and Trentino Alto Adige (n=241) regions, 24 animals, all from the Trentino Alto Adige region, were found positive. Twenty-two positive animals originated from the Bolzano province and two positive animals from the Trento province. Several localities of the Bolzano province, in which positive foxes were detected, are the same as those where alveolar echinococcosis had been described in humans in the second half of the 19th century, suggesting an old endemicity for the investigated area, which is adjacent to endemic areas of Austria. Therefore, the question arises if we are observing an increase and expansion of foci, or if the new records are due to the more sensitive and specific methods used to detect the worm DNA.
Animal Diseases↗