The International Trichinella Reference Centre database. Report on thirty-three years of activity and future perspectives.

The International Trichinella Reference Centre (ITRC) is the official laboratory of the International Commission on Trichinellosis, of the World Organization for Animal Health and of the European Union Reference Laboratory for Parasites. The ITRC was established in 1988 as a repository of Trichinella strains and a source of reference materials and information for international scientific research. To date, more than 8000 Trichinella isolates collected throughout the world have been identified at the species or genotype level by the ITRC staff and the information has been stored in a freely accessible database providing the largest collection of data available for scientists involved in the systematics and epidemiology of this parasite. This paper presents a summary of the data collected over 33 years of activity and describes the database functionalities. It finally advocates the potential of the database to improve knowledge of the epidemiology and taxonomy of Trichinella, which in turn may help the international surveillance of Trichinella species.

Rare but evolutionarily consequential outcrossing in a highly inbred zoonotic parasite.

Recurrent self-mating can result in nearly clonal propagation of biological lineages, but even occasional outcrossing can serve to redistribute variation in future generations, providing cohesion among regional populations. The zoonotic parasite Trichinella spiralis has been suspected to undergo frequent inbreeding, resulting in genetically uniform larval cohorts which differ markedly from one another. Here, we explored the extent of inbreeding for this parasite by determining how genetic variation (at variable microsatellite markers) is distributed among 1379 larvae derived from 41 wild boars in Extremadura, Spain. In particular, we sought to determine how much of the genetic variation in this region's parasites occurs among the larvae of any given wild boar, and whether each derives from one, or more, parental lineages. We found strong evidence for inbreeding, resulting in genetically distinct parasite subpopulations among the parasites derived from many pairs of wild boar. Fully two-thirds of these parasite cohorts appear to derive from inbred parents; in 10% of the wild boars, parasites were so inbred as to become absolutely fixed in all of the assayed genetic loci. In spite of this, more than one pair of parents appear to have given rise to the infections in one-third of the sampled wild boars, resulting in mixed infections. These mixed infections should slow losses of heterozygosity and multi-locus polymorphism in any given parasite lineage. Such outcrossing should limit distinctions that would otherwise accumulate among transmission chains, thereby enforcing cohesion through the region's population in spite of its marked departure from panmixia. Conditions of transmission may differ in other regions, where such epidemiological features may engender different evolutionary outcomes.

Proficiency testing to detect Trichinella larvae in meat in the European Union.

According to the Commission Implementing Regulation (EU) 2015/1375 (replacing the Commission Regulation (EC) No 2075/2005), all animals, which are potential carriers of Trichinella spp. larvae, should be tested at the slaughterhouse or game-handling establishments according to one of the approved tests. One of the core duties of the European Union Reference Laboratory for Parasites is to organize proficiency testing (PT), as stated in the Commission Regulation (EC) No. 882/2004 of the European Parliament and of the Council. The aim of this work was to evaluate the results of PTs of the digestion method carried out by the National Reference Laboratories for Parasites (NRLPs) over a nine year period (2007-2015). Participating laboratories received a panel of samples consisting in 35g or 100g of minced pork or horse meat spiked with Trichinella spiralis live larvae. The number of spiked samples varied from 2 to 9 over the years. A negative control was also included in the panel, except during the 2015 PT, when only positive samples were used. The percentage of NRLPs, which passed the PT, increased from 83.3% in 2007 to 100% in 2014. Considering the number of recovered larvae, the heterogeneity in participant's results reduced overtime. The values of the overall mean difference between spiked and recovered larvae decreased during the study period, witnessing a general improvement of NRLPs performance and confirming the effectiveness of PT for a good performance of this test.

A novel Giardia duodenalis assemblage A subtype in fallow deer.

The molecular identification of species and genotypes of Giardia spp. infecting wild mammals represents the most reliable tool to understand the role played by these animals as reservoirs of cysts infectious for human and other animals. Of 139 fecal samples collected from fallow deer (Dama dama L.) hunted in a Natural Reserve of northern Italy, the prevalence of Giardia sp. was 11.5% (16 of 139 animals), and it was higher in fawns than in older animals. Fragments of the betagiardin and triose phosphate isomerase (tpi) genes were successfully polymerase chain reaction amplified and sequenced from 8 isolates. No sequence variation was observed between isolates at the 2 genetic loci. Sequence and phylogenetic analyses identified a Giardia duodenalis subtype that clusters with assemblage A isolates and that shows homologies of 98 and 97% at the beta-giardin and tpi loci, respectively, compared with the A1 subtype. Because the G. duodenalis subtype found in fecal samples of fallow deer has never been detected previously, its role as a pathogen for humans and domestic animals is unknown, but, considering its genetic distinctiveness, it is likely to be low.