Gelatin medium for preserving of Trichinella spp. for quality control in laboratories - estimation of larvae viability

INTRODUCTION AND OBJECTIVE

Official food control laboratories ensure food safety using reliable, validated methods. Council Regulations (EC) No. 853/2004, 854/2004 and 882/2004 of the European Parliament established hygiene rules the production of food of animal origin, together with requirements for official controls. This leads to detailed requirements for Trichinella control set out in Commission Implementing Regulation (EU) 2015/1375 of 10 August 2015. These regulations require the laboratory to participate in proficiency testing (PT) to confirm their competence and improve the quality of testing, and require the PT Organizer to use methods for the preparation and preservation of parasite larvae in order to evaluate and improve detection. Traditional methods of preparing such larvae expose them to rapid degradation, making it necessary to simultaneously isolate the larvae and place them in meatballs to ensure quality.

MATERIAL AND METHODS

We developed a technique for preserving of Trichinella spp. for quality control such as PT sample preparation. The procedure protects larvae against toxic oxygen activity and bacterial destruction via a gelatin barrier. To estimate the viability of larvae preserved by this method, gelatin capsules with 10 larvae of T. spiralis in each were stored (4-8 °C) during 45 days of an experiment. Samples were tested at 2 day intervals (3 samples each day of testing).

RESULTS

In total, 75 samples were tested. Larvae remained alive up to 3 weeks. The number of living larvae diminished after 27 days through day 43, after which no living larvae were observed.

CONCLUSIONS

The gelatin medium procedure facilitated easy, high-throughput sample preparation and supported 100% recovery for 3 weeks. The method allows fast, efficient and accurate PT sample preparation.

Echinococcus multilocularis genetic diversity based on isolates from pigs confirmed the characteristic haplotype distribution and the presence of the Asian-like haplotype in Central Europe

Introduction

The aim of the study was to determine the genetic diversity of Echinococcus multilocularis in pigs in highly endemic areas in Poland, as well as to attempt to confirm the occurrence and geographical distribution of haplotypes characteristic for these areas, which were previously described on the basis of examination of adult tapeworms isolated from foxes.

Material and Methods

Twenty samples of E. multilocularis larval forms were obtained from pigs' livers in four provinces of Poland. Genetic analyses were conducted on sequences of two mitochondrial genes: cox1 and nad2.

Results

Seven haplotypes were found for the cox1 gene (OQ874673-OQ874679) and four haplotypes for nad2 (OQ884981-OQ884984). They corresponded to the haplotypes described earlier in foxes in Poland (some of them differing only in one nucleotide). The analysis showed the presence of the Asian-like haplotype in both the cox1 and nad2 genes. The remaining haplotypes were grouped in the European clade. The geographical distribution of haplotypes identified in the pig samples was noticed to bear a similarity to the distribution of haplotypes previously isolated from foxes in the same regions.

Conclusion

The characteristic geographical distribution of E. multilocularis haplotypes in Central Europe (including the presence of the Asian-like haplotype) previously described in the population of definitive hosts (foxes) has now been confirmed by the analysis of samples from non-specific intermediate hosts (pigs).

Comparison of the effectiveness of selected essential oils with mineral oil and spinosad on Dermanyssus gallinae

It seems that essential oils can be a good ingredient in effective preparations against Dermanyssus gallinae. Dermanyssus affects animal health leading to financial losses and bird welfare issues. Collected mites were treated with various essential oils in four (20, 50, 80 and 100%) concentrations at a dose of 0.28 mg/cm2. The direct toxicity of the essential oils, mineral oil and spinosad to D. gallinae was tested in the laboratory. Eucalyptus oil was the most toxic essential oil in all concentrations to D. gallinae (87.6 - 97.6% mortality at all four concentrations), while geranium, pine and rosemary oils showed mortality rates of 14.2 - 68.2%. High mortality after 48 hours of contact was also recorded for the oil of cloves at 80% dilution (85.1% mortality), lavender 100% (94.2% mortality). Similarly, the thyme essential oil produced 83.5 - 93.2% mortality in three concentrations: 50, 80 and 100%. The mineral oil was the least effective oil against mites. Spinosad showed high effectiveness against D. gallinae.

Molecular Confirmation of Massive Taenia pisiformis Cysticercosis in One Rabbit in Poland

The aim of this study was to provide molecular characterization, together with phylogenetic analysis, of Taenia pisiformis cysts isolated from rabbit. On the basis of morphological features and molecular analysis, the cysticerci were identified as T.pisiformis metacestodes. PCR was performed with three different protocols to obtain partial sequences of 12S ribosomal RNA (12S rRNA), NADH dehydrogenase subunit 1 (nad1), and cytochrome oxidase subunit 1 (cox1) of Taenia spp. The products from the PCRs were sequenced. Interpretation of the sequencing results of the obtained amplicons, by comparing them with the GenBank database, proved that the causative agent, in this case, was T. pisiformis. The phylogenetic analysis of the received sequences identified a new haplotype. The received data can be used to supplement the species description. To our knowledge, this is the first molecular confirmation of T. pisiformis metacestodes infection in the rabbit, in Poland.

The First Record of Echinococcus ortleppi (G5) Tapeworms in Grey Wolf (Canis lupus)

The aim of this study is to confirm the presence and molecular identification of Echinococcus tapeworms in wolves from south-eastern Poland. An investigation was carried out on the intestines of 13 wolves from south-eastern Poland. The small intestines were divided into three equal segments. Each segment was separately examined using the sedimentation and counting technique (SCT). The detected Echinococcus tapeworms were isolated and identified by PCRs and sequencing (nad1 and cox1 genes). Additionally, DNA isolated from the feces of wolves positive for Echinococcus tapeworms was examined with two diagnostic PCRs. The intestines of one wolf were positive for E. granulosus s.l. when assessed by SCT; the intestine was from a six-year-old male wolf killed in a communication accident. We detected 61 adult tapeworms: 42 in the anterior, 14 in the middle, and 5 in the posterior parts of the small intestine. The PCRs conducted for cox1 and nad1 produced specific products. A sequence comparison with the GenBank database showed similarity to the deposited E. ortleppi (G5) sequences. An analysis of the available phylogenetic sequences showed very little variation within the species of E. ortleppi (G5), and identity ranged from 99.10% to 100.00% in the case of cox1 and from 99.04% to 100.00% in the case of nad1. One of the two diagnostic PCRs used and performed on the feces of Echinococcus-positive animals showed product specific for E. granulosus. This study showed the presence of adult E. ortleppi tapeworms in wolves for the first time.

Tritrichomonas Foetus: A Study of Prevalence in Animal Hosts in Poland

Tritrichomonas foetus is described as a pathogen of cattle and cats and also exhibits commensalism with pigs. In order to estimate the prevalence and determine the risk factors for parasite infection, specimens from animal hosts (cat, pigs, and cattle) from Poland were investigated. To our best knowledge, this is the first such study to examine samples from wild boars (Sus scrofa) for the presence of T. foetus. Data were collected from 117 cats, 172 pigs, 236 wild boars, and 180 cattle. The sensitivity of T. foetus identification was increased by using two molecular assays: PCR and loop-mediated isothermal amplification (LAMP). The prevalence of feline tritrichomonosis was 20.51%, and statistically significant differences were obtained between groups of animals regarding age, breed, number of cats, diarrhea, and place of living. Positive PCR and LAMP results for T. foetus were estimated for 16.28% of pigs, and the obtained data were significantly correlated with age. Conversely, no significant differences were observed concerning the farm size factor. In our survey, no cases of bovine tritrichomonosis were found, which is consistent with the data from the other countries of the European Union. Similarly, all wild boar samples were also T. foetus-negative according to LAMP and PCR.

First case of Trichinella spiralis infection in beavers (Castor fiber) in Poland and Europe

Background

This is the first report of the finding of Trichinella spiralis in beaver meat (Castor fiber) in Poland and Europe. In Poland, the beaver is a strictly protected animal species, except the few regions where high population density leads to economic losses. In these areas, the reduction culling of the animals was introduced. This uncommon hunting game animal is consumed and treated as a delicacy by hunters. However, currently, there is a lack of knowledge on possible risk factors for humans associated with the consumption of beaver meat. This paper presents the result of the study on the occurrence of nematodes of the genus Trichinella in beavers.

Methods

In total, 69 beavers were examined for the presence of Trichinella spp. The 50g samples were taken from each animal and digested separately, according to a procedure based on the EU reference method. The larva DNA was examined by PCR and sequencing.

Results

One of the 69 examined beavers was infected. Only one Trichinella larva was detected by the digestion method. The result of PCR confirms the presence of T. spiralis in beaver meat.

Conclusions

This case further confirms the ability of these typical herbivores to be infected with Trichinella spp. This is the second confirmed case of Trichinella spp. infection in beavers in Europe and the first of T. spiralis.

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First report of the presence of Trichinella spiralis larva in beaver meat.

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Detection of Trichinella spiralis by digestion method and confirmed by PCR and sequencing.

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New parasitic risks factor for humans associated with consumption of beaver meat.

Tritrichomonas Foetus as a Causative Agent of Tritrichomonosis in Different Animal Hosts

Tritrichomonas foetus is a protozoan parasite that has been traditionally identified as a cause of reproductive tract disease in cattle and gastrointestinal tract infection in cats. Moreover, T. foetus is also well known as a commensal of the nasal cavity, intestines, and stomach in swine. In this review we describe T. foetus as a pathogen dangerous to more than one animal host, diagnostic and taxonomic aspects of this infection, and the extent to which isolates from different hosts share genetic identity.

Intraspecific genetic variation in Trichinella spiralis and Trichinella britovi populations circulating in different geographical regions of Poland

Trichinella spiralis and Trichinella britovi are species of nematodes which are responsible for the majority of Trichinella infections in the world and the most prevalent in Poland. The most abundant species – T. spiralis, is considered to be more genetically homogeneous in Europe than T. britovi. The aim of the present study was to determine the genetic variability in T. spiralis and T. britovi populations based on nuclear 5S rDNA intergenic spacer region (5S rDNA) and cytochrome c oxidase 1 (COX1) gene sequences. For the study, 55 isolates of T. spiralis and 50 isolates of T. britovi isolated from wild boars, pigs, brown rat and a red fox were analyzed. Based on the analysis of both genes, the genetic variability within populations of T. spiralis and T. britovi differed. In T. spiralis, two single nucleotide polymorphisms (SNPs) were observed in the 612 bp 5S rDNA gene fragment, and one SNP was detected in the 700 bp COX1 gene fragment. In T. britovi, 17 single nucleotide variations (SNVs) were detected in the 5S rDNA gene fragment (among them 16 SNPs), while COX1 sequence analysis revealed the occurrence of 20 SNVs between the sequences tested (among them 19 SNPs).

For the majority of T. spiralis isolates the investigated larvae presented uniform haplotypes. In contrast, most of the isolates of T. britovi consisted of larvae of different haplotypes. Geographical analysis showed that each region exhibited different haplotype composition and richness. Warmińsko-Mazurskie and Zachodniopomorskie regions were the richest in haplotypes (15 and 16 haplotypes, respectively). We used heatmaps showing a characteristic pattern for each region graphically. This may allow to differentiate regions based on the occurrence of particular haplotypes. Furthermore, a PCA analysis on the SNP level yielded biplots that show that certain haplotypes/genotypes are associated with (clusters of) regions.

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The genetic variability within the Polish T. britovi population is high.

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5S rDNA and COX1 variability in T. spiralis is low compared to T. britovi.

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T. britovi variability may correlate to geographical origin.

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Heatmap and PCA analysis could be helpful analytical tool for epidemiological investigations.

First report of Echinococcus multilocularis in cats in Poland: a monitoring study in cats and dogs from a rural area and animal shelter in a highly endemic region

BACKGROUND

Alveolar echinococcosis is a dangerous zoonotic disease caused by larval forms of Echinococcus multilocularis. In its life-cycle, the principal definitive host is the red fox; however, domesticated carnivorous animals (dogs and cats) can also act as definitive hosts. Until now, there were no data concerning this infection in cats in Poland. The aim of this study was to estimate the prevalence of E. multilocularis in cats and dogs originating from rural areas and animal shelters in a region characterised by a high prevalence of E. multilocularis in red foxes.

METHODS

Samples of faeces were collected from 67 cats and 268 dogs from a rural area (villages and animal shelters) of a highly endemic region in southeastern Poland. Samples were examined using nested PCR (E. multilocularis), multiplex PCR (E. multilocularis, Taenia spp.) and PCR [E. granulosus (s.l.)]. Additionally, faeces were examined microscopically (flotation). Moreover, intestines from 110 red foxes shot in the investigated area were examined (sedimentation and counting technique).

RESULTS

Positive PCR results for E. multilocularis were obtained in 4 cats (6.0%) and 4 dogs (1.5%). There were no significant differences between groups of animals (from a shelter and with an owner) concerning the prevalence of E. multilocularis in both cats and dogs. Taenia spp. were found in 10 cats (14.9%) (Taenia taeniaeformis and T. hydatigena) and 26 dogs (9.7%) (T. hydatigena, T. serialis, T. taeniaeformis, T. crassiceps, T. pisiformis and T. ovis) and Mesocestoides litteratus was found in 4 cats (6.0%) and 3 dogs (1.1%). All samples were negative for E. granulosus by PCR. Taking into consideration PCR and flotation results, 29 cats (43.3%) and 73 dogs (27.2%) were infected with helminths (26.9 and 11.9%, respectively, were infected with tapeworms). The highly endemic status of the investigated area was confirmed by examination of red foxes: 48.2% of examined red foxes were infected with E. multilocularis.

CONCLUSIONS

To the best of our knowledge, this study reports the presence of E. multilocularis in cats for the first time in Poland and confirms the role of dogs in this infection in highly endemic areas.

Parasitological contamination with eggs Ascaris spp., Trichuris spp. and Toxocara spp. of dehydrated municipal sewage sludge in Poland

The objective of the present study was to evaluate the contamination of sewage sludge produced by municipal waste treatment plants in Poland by viable eggs of intestinal parasites of the genera Ascaris, Toxocara and Trichuris (ATT). Ninety-two municipal, mechanical-biological sewage treatment plants located within Poland were selected. These plants belonged to types of agglomerations: group 0 (large), group 1 (medium), group 2 (smaller) and group 3 (small). Samples were collected at the final stage of sewage treatment after the addition of flocculent to sludge, followed by dehydration. The samples were examined by a method adjusted to examine sewage sludge dehydrated using polyelectrolytes. The viability of the isolated eggs was evaluated based on incubation in a moist chamber. Live eggs of intestinal nematodes were found in 99% of samples. Most samples were contaminated by the eggs of Ascaris spp. (95%) and Toxocara spp. (96%). However, Trichuris spp. eggs were detected in 60% of samples. The mean number of eggs in 1 kg of dry mass (eggs/kg d.m.) was 5600 for Ascaris, 3700 for Toxocara and 1100 for Trichuris. The highest number of ATT eggs was detected in samples from sewage treatment plants located in south-eastern and central Poland. The highest number of ATT eggs was found in sewage sludge produced in large sewage treatment plants (agglomeration Groups 0 and 1), with mean values of 15,000 and 8900 eggs/kg d.m. The present study is the first parasitological investigation conducted on a large number of samples (92 samples) taken from various types of municipal sewage treatment plants located throughout Poland (16 regions) after the common introduction of polyelectrolytes during sewage sludge dehydration. The results of this study indicate that sludge produced in municipal sewage treatment plants is highly contaminated with parasite eggs.

Negative effect of flocculant (cationic acrylamide) on detectability of the nematode eggs in sewage sludge

The use of sewage sludge in agriculture brings the risk of microbiological and parasitological contamination of soil, ground and surface water, as well as cultivated plants. Therefore prior the application to the soil, sewage sludge must be examined, among others, for the presence of live eggs of intestinal parasites. However, the efficiency of commonly used for this purpose parasitological methods is not satisfactory. This is probably due to the presence of flocculants in the sediments used in the dehydration process. The objective of the study was analysis of the effect of flocculant (cationic acrylamide) on the possibilities of isolation of parasite eggs from dehydrated sewage sludge. For this purpose 10 samples of sewage sludge were prepared: 5 containing flocculant and 5 without flocculant. Samples were tested by flotation method according to Quinn. From sewage sludge free of flocculant, 67.8 eggs were isolated, on average, whereas from sludge containing flocculant - only 2.8 eggs. The experiments confirmed that the isolation of eggs from sewage sludge containing flocculant (cationic acrylamide) is much more difficult than from sludge free from this substance and therefore the simple parasitological methods should not be used to examine the dehydrated sewage sludge.

Occurrence of Trichinella spp. in rats on pig farms

INTRODUCTION

The highest risk of trichinellosis for human is considered in eating meat products containing live larvae, mostly from wild boars or pigs. Spreading of Trichinella spp. may occur in various ways, one of which is transmission by vectors. The rat is considered to be the most common vector for Trichinella parasite. The population of rats living on pig farms can play an important role in maintaining or spreading the parasite to other animals.

OBJECTIVE

The aim of presented survey was to investigate the occurrence of Trichinella spp. in rats on farms with pigs infected with this parasite.

MATERIAL AND METHODS

From pig farms selected for study, the muscles of collected rats were investigated by magnetic stirrer digestion method to assess occurrence of Trichinella in the rat population. Isolated Trichinella parasites were identified under stereomicroscope and multiplex PCR were performed for species identification.

RESULTS

Rats infected with Trichinella spp. were discovered on three of five investigated pig farms. The mean extent of invasion in rats from the studied farms was 23.33%. The calculated medium intensity of invasion was 4.09 lpg (larvae per gram) (SD 5.41). All larvae of Trichinella discovered from rats were identified as T.spiralis.

CONCLUSIONS

The results obtained indicate that in farms with a high prevalence of Trichinella invasion in pigs there are very likely to be found rats infected by this nematode. This suggests possibility to maintain the invasion in herd and spread into neighborhood farms.

Prevalence of intestinal helminths of red foxes (Vulpes vulpes) in central Europe (Poland): a significant zoonotic threat

BACKGROUND

The red fox (Vulpes vulpes) is widely distributed in the world; in central Europe, it is the most numerous wild species of the family Canidae. It can play the role of a definitive host for many intestinal parasites, including zoonotic helminths. Poland, with its geographical location (central Europe), is an interesting area for parasitological investigations of this species. The aim of this study was to evaluate and compare the prevalence of intestinal helminths in red foxes in different regions of Poland.

METHODS

Intestines of 473 red foxes from four different regions were examined using the sedimentation and counting technique (SCT). In addition, 344 samples of faeces were examined using flotation.

RESULTS

Overall, intestinal helminths were found in 98.9% of red foxes. The average prevalence of detected parasites was as follows: Mesocestoides spp. (84.1%); hookworms (67.9%); Alaria alata (61.5%); Toxocara/Toxascaris (49.5%); Taenia spp. (42.5%); Echinococcus multilocularis (25.6%); and Trichuris vulpis (2.3%). The prevalence of the majority of parasite species was similar in each region. Significant differences between regions were observed in the case of E. multilocularis: a low prevalence in the south-western and northern regions (0% and 0.9%, respectively) and a high prevalence in the south-east and northeast (39.3% and 42.7%, respectively). In the case of A. alata, important differences were found between northern (96.5% and 93.7% in northern and northeast regions, respectively) and southern regions (15.2% and 24.7% for south-western and south-east regions, respectively). The percentage of positive samples obtained with coproscopic examination (except for Trichuris) was significantly lower than that obtained with SCT. Analysis of the prevalence estimated in individual regions with the use of both methods (flotation and SCT) showed a high correlation for all parasite species (except for Mesocestoides spp.). The flotation method also allowed us to detect the eggs of the lung nematode Eucoleus aerophilus (syn. Capillaria aerophila) (76.2% of positive foxes).

CONCLUSIONS

This study showed a very high percentage of red foxes infected with intestinal helminths in different parts of Poland. Depending on the location, some differences were observed regarding the prevalence of dangerous zoonotic parasites, which should be considered in the assessment of infection risk for humans.

Viability assessment of Ascaris suum eggs stained with fluorescent dyes using digital colorimetric analysis

The aim of the study was to develop a method for the colorimetric evaluation of nematode eggs using appropriate instruments. The materials for the study were live and dead (inactivated) eggs of the Ascaris suum. Viability of the eggs was assessed using four different kits for fluorescent staining (for each technique, a series of photos were taken). Images of stained eggs were analysed using graphic software with RGB (red-green-blue) function. The viability of the eggs was assessed according to the relative positions of the distributions of colour intensities of live or dead eggs - distributions area's overlap index (DAOI), and distributions area's separation index (DASI) were calculated. Computer analysis of the intensity of green colour was not satisfactory. However, analysis of images in the spectrum of red colour proved useful for the effective differentiation between live or dead eggs. The best parameters were observed using the Annexin V FITC Apoptosis Detection Kit (DASI = 41 and 67). The investigation confirmed the usefulness of fluorescent dyes used in conjunction with digital analysis for the assessment of the viability of A. suum eggs. The use of computer software allowed a better objectivity of the assessment, especially in the case of doubtful staining.

Intestinal helminths of raccoon dogs (Nyctereutes procyonoides) and red foxes (Vulpes vulpes) from the Augustów Primeval Forest (north-eastern Poland)

Introduction: The aim of the study was to determine the prevalence of intestinal helminths in red foxes (Vulpes vulpes) and raccoon dogs (Nyctereutes procyonoides) in the Augustów Primeval Forest (north-eastern Poland), with particular regard to zoonotic parasites.

Material and Methods: Intestines from 53 raccoon dogs and 66 red foxes were examined with the use of sedimentation and counting technique (SCT). Samples of faeces from 51 red foxes and 50 raccoon dogs were examined with the use of flotation method.

Results: Parasitic helminths were found by SCT in 98.5% of red foxes and 96.2% of raccoon dogs. Both species were infected with: Alaria alata (93.9% and 94.3%, respectively), hookworms (68.2% and 83.0%), Apophallus spp. (7.6% and 15.1%), Mesocestoides spp. (57.6% and 24.5%), Taenia spp. (40.9% and 1.9%), and Toxocara/Toxascaris nematodes (33.3% 15.1%). Echinococcus multilocularis was detected only in red foxes (6.1%), but trematodes Echinostomatidae and nematodes Molineus spp. only in raccoon dogs (18.9% and 41.5%, respectively). Additionally, Capillaria spp. eggs were detected by flotation method in 78.4% of foxes and 20.0% of raccoon dogs.

Conclusion: The study showed a very high percentage of red foxes and raccoon dogs infected with intestinal helminths in the Augustów Primeval Forest. Moreover, dangerous zoonotic parasites also were found, which should be taken into consideration in the assessment of infection risk for humans in this region.

Effectiveness of Selected Stages of Wastewater Treatment in Elimination of Eggs of Intestinal Parasites

The objective of the study was to determine the degree of municipal wastewater contamination with intestinal parasite eggs of the genera Ascaris, Toxocara, and Trichuris at individual stages of treatment, and indication of potentially weak points in the hygienisation of sewage sludge. The study was conducted in 17 municipal mechanical-biological wastewater treatment plants which, to a slight degree, differed in the technological process of wastewater treatment and the method of hygienisation of sewage sludge. The selected treatment plants, located in seven regions, included five classified as large agglomerations (population equivalent - PE >100 000), ten as medium-size (PE 15 000-100 000), and two as smaller size with PE 10 000 - 5000. The largest number of viable eggs of Ascaris spp., Toxocara spp., and Trichuris spp. was found in the sewage sludge collected from the primary settling tank. A slightly lower number of the eggs were found in the samples of excess sludge, which indicates that the sedimentation process in the primary settling tank is not sufficiently long to effectively separate parasites’ eggs from the sewage treated. The number of eggs of Ascaris spp. and Toxocara spp. in the fermented sludge was nearly 3 times lower than that in the raw sludge. The effectiveness of hygienisation of dehydrated sewage sludge by means of quicklime was confirmed in two wastewater treatment plants, with respect to Ascaris spp. eggs, in three plants with respect to Toxocara spp. eggs, and in one plant with respect to Trichuris spp. eggs. The mean reduction of the number of eggs was 65%, 61%, and 100%, respectively. In one wastewater treatment plant, a reduction in the number of viable eggs of Ascaris and Trichuris species was also noted as a result of composting sludge by 85% and 75%, respectively. In the remaining treatment plants, no effect of hygienisation of sewage sludge was observed on the contents of viable eggs of these nematodes.

Assessment of viability of the nematode eggs (Ascaris, Toxocara, Trichuris) in sewage sludge with the use of LIVE/DEAD Bacterial Viability Kit

Sewage sludges from wastewater treatment plants may contain live parasite eggs, which can be a source of humans and animals infection. According to the current rules, parasitological examination includes detection of the Ascaris spp., Trichuris spp. and Toxocara spp. eggs and estimation of their viability. The viability assessment based only on the incubation and observation of isolated egg is long and imprecise. The aim of this study was to develop sensitive and less labour-intensive methods for assessing viability of Ascaris spp., Toxocara spp. and Trichuris spp. eggs in sewage sludge. For this purpose, LIVE/DEAD Kit was used. Firstly, the possibility of distinguishing between live and dead eggs in water was assessed. Secondly, an appropriate amount of dyeing mixture needed to distinguish the live and dead eggs in the sewage sludge was determined using experimentally enriched samples and naturally contaminated samples of sludge. Eggs were isolated from the samples by own method which was a combination of flotation and sedimentation, preceded by a long mixing. After the last stage of the procedure, sediment containing the eggs of parasites was stained by LIVE/DEAD kit according to the manufacturer instructions, but with the use of different variants of dyes mixture concentration. The investigation showed that live and dead eggs of these three parasites could be differed by this method with the use of proper concentration of dyes. Live eggs were stained in green (Ascaris and Trichuris) and green-blue (Toxocara). However, all types of dead eggs were red coloured. The study demonstrated that after some modifications (resulted from the nature of the samples) the LIVE/DEAD kit is useful for assessing the viability of Toxocara, Ascaris and Trichuris eggs occurring in the sludge.

Occurrence of Cryptosporidium oocysts and Giardia cysts in effluent from sewage treatment plant from eastern Poland

Cryptosporidium spp. and Giardia lamblia (synonyms: Giardia duodenalis, Giardia intestinalis) are emerging protozoa causing disease in humans and animals worldwide. These parasites can pose a serious threat to immunocompromised people, for whom the symptoms are more severe and may include abdominal pain, watery diarrhoea, nausea, headaches, malaise, and fever. One of the sources of these parasites can be treated wastewater from wastewater treatment plants (WTPs). Samples of treated wastewater (effluent), each of 10 L volume, were collected from 13 municipal WTPs located in eastern Poland. Cryptosporidium oocysts and Giardia cysts were separated by the immunomagnetic method. The presence and/or concentration of protozoan (oo)cysts in effluent samples were determined by direct immunofluorescent microscopy, nested PCR and Real Time PCR. Viability of (oo)cysts was determined by double-staining with the use of Live/Dead BacLight kit (Invitrogen). Cryptosporidium spp. oocysts were detected in 8 WTPs (61.5%) and Giardia spp. cysts in 11 WTPs (84.6%) by microscopic analysis. Both pathogens were detected in samples from 7 WTPs. Median concentrations of Cryptosporidium and Giardia (oo)cysts in 13 examined samples were 2.2/L and 6.6/L, respectively, while mean concentrations were 28.5/L and 113.6/L, respectively. In positive samples, Cryptosporidium oocysts concentrations ranged from 0.4 - 154.1 oocysts per litre, and Giardia cysts concentrations ranged from 0.7 - 660 cysts per litre. By nested PCR, Giardia DNA was detected in 4 samples of the 13 examined, (30.8%) while Cryptosporidium DNA was never detected. In Real Time PCR, positive results for Giardia were obtained in 5 samples (38.5%) and in none of the samples for Cryptosporidium, with the exception of one equivocal result. Viable (oo)cysts of Cryptosporidium and Giardia were detected in 3 out of 4 samples examined, in the ranges of 12.5 - 60% and 50 - 100% of total (oo)cysts, respectively. In view of our preliminary study, the presence of oocysts and cysts (largely viable) in effluents from WTPs imply a risk of transmission of waterborne protozoan parasites to humans. Therefore, additional wastewater purification procedures are necessary.