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The distribution of Alaria-spp.-mesocercariae within the host is relevant for the examination via Alaria spp. mesocercariae migration technique (AMT) regarding predilection sites and may indicate an interaction between parasite and host. Naturally Alaria-exposed frogs of Pelophylax species (n = 13) were examined for systemic distribution and localization-specific parasite density of Alaria spp. mesocercariae. The frogs were necropsied and their body was divided into the following localizations: inner organs, head, torso, forelimbs, and hind limbs. The localizations were analyzed individually and in toto using Alaria spp. mesocercariae migration technique. Our results showed neither statistical differences concerning the number of mesocercariae in the different localizations nor in respect of the rate of positive localizations. Therefore, an accumulation in a particular predilection site seems unlikely. Further research on a representative sample is necessary before final conclusions can be drawn.

Several methods for the detection of Trichinella in meat are legally prescribed in regulation (EC) No 2075/2005, which prescribes the magnetic stirrer method for pooled sample digestion (MSM) as the reference method. However, the MSM's multistage protocol requires several preparatory steps that seem to be accountable for the loss of larvae. Here we present a modified MSM (mMSM) based on: (1) an inversion of the optical path using inverse microscopy; and (2) a modified larval counting basin (mLCB, ‘Trichoview’). This enables one to examine samples of up to 40 ml and reduces the examination area from 72 to 10.3 cm2. Preparatory steps that might cause the loss of Trichinella larvae are eliminated from the new protocol. Correspondingly, the overall analytical time is reduced. In a direct and blinded comparison using 60 digest samples containing spiked vital Trichinella larvae (1–90 L1), both methods performed well for both small and large numbers of L1. However, 1278 of 1285 L1 (99.4%) were detected using the mMSM, while MSM recovered only 1225 L1 (95.3%). The improvement stems largely from samples with small numbers of L1: in all samples spiked with fewer than 10 L1, the recovery rate of mMSM was 100% compared to only 93% with MSM. Our data suggest that the use of the mMSM can improve the recovery rate by about 4% and therefore reduce the chances of a false-negative result in a sample containing 5 larvae by a factor of about 4.

Trichinosis (Trichinellosis) is a zoonotic disease acquired by eating raw or not adequately processed pork or wild game infected with the larvae of the roundworm genus Trichinella. According to European regulations, animals susceptible to Trichinella have to be examined for infestation. To evaluate the performance of laboratories in Germany, inter-laboratory comparisons known as "ring trials" were introduced by the Federal Institute for Risk Assessment in 2004. The current method of analysis makes use of tolerance zones based on the number of larvae in the sample, but does not permit one to determine if a given lab can detect an infested sample reliably, as required by the quality assurance recommendations of the International Commission on Trichinellosis (ICT). A new way of analysing the ring trial data is presented here, which is based on Bayesian hierarchical models. The model implements the ICT requirement by providing an estimate for the probability that a given lab would fail to detect a sample containing, say, five larvae. When applied to the 87 labs that participated in Germany's 2009 ring trials, it turns out this probability is greater than 10% for 21 of them, although only 10 of these in fact returned a false negative result. Such a new method is required to abide by the ICT requirements and make ring trials effective.

Proficiency testing (PT) is the use of inter-laboratory comparisons to determine the performance of individual laboratories for specific tests or measurements, and to monitor a laboratory's performance. Participation in proficiency testing provides laboratories with an objective means of assessing and demonstrating the reliability of the data they are producing. To ensure the reliability of Trichinella detection and meat hygiene within the European Union and afford optimal protection to the consumer, PT is conducted under the direction of the European National Reference Laboratories for Trichinella. Evaluation of data from the national PT showed that lab-internal shortcomings are frequent. These shortcomings are specifically related to: (1) improper sample collection and preparation; (2) incorrect transposition and application of the protocol as laid down in Annex I, Chapter I, Nr. 3 (a-g) of the Commission Regulation (EC) No. 2075/2005; (3) insufficient sedimentation times; and (4) improper equipment.(e.g. Prost and Nowakowski, 1990; Rossi and Pozio, 2008; Forbes and Gajadhar, 1999; Rossi and Pozio, 2008). To test the hypothesis that both method based errors as well as internal lab errors can influence the accuracy and precision of the magnetic stirrer method for pooled sample digestion (MSM), we initiated a study to evaluate the analytical uncertainty of the MSM. Results presented here are based on: (i) data from PT in Germany (2008, 2009, and 2010); (ii) within-lab performance conducting high volumes of MSM; (iii) larval recovery experiments; and (iv) statistical evaluation of data resulting from these procedures. Quantitative data from the PT show that on average only 60% of Trichinella larvae were detected. Even laboratories that showed relatively good performance (>80% larva recovery, no false negative or false positive results), frequently reported samples with an unexpectedly low larval count (loss of >2 larvae). In our own laboratory, high numbers of repeated analyses of standards and re-analyses of residual fluids indicated that these outliers could be described by a binomial distribution based on a laboratory-specific Trichinella-detection probability. Results of recovery experiments indicate that only a part of the total larval losses can be attributed to lab-internal shortcomings inasmuch as a significant number of L1 could be isolated from the residual and washing fluids.