Migratory pattern of zoonotic Toxocara cati and T. canis in experimentally infected pigs.

BACKGROUND: Over a billion people are infected with Toxocara canis or T. cati, the roundworms of dogs and cats. Historically, T. canis has been considered the main species responsible for human toxocarosis, but as serodiagnosis cannot discriminate between the two species, this remains unresolved. We used pigs as a relevant large animal model for human infection to assess the migratory pattern of T. cati and T. canis. METHODS: Pigs were inoculated with T. cati or T. canis eggs or PBS (negative controls) and necropsied 14 or 31 days later. Different organs and tissues were examined for parasites and pathological changes. RESULTS: Overall, the two parasite species had a similar migration pattern reaching multiple organs and tissues, including the mesenteric lymph nodes, liver, lungs, and diaphragm. We recovered larvae of both species in the brain, suggesting that T. cati also can cause neurological toxocarosis in humans. Both species induced systemic eosinophilia and histopathological changes in the lungs, livers, and mesenteric lymph nodes. CONCLUSION: This study emphasises the importance of T. cati as a zoonotic agent and the need to develop diagnostic methods that can differentiate between sources of infection in humans.

Dietary seaweed (Saccharina latissima) supplementation in pigs induces localized immunomodulatory effects and minor gut microbiota changes during intestinal helminth infection.

Brown seaweeds have a rich bioactive content known to modulate biological processes, including the mucosal immune response and microbiota function, and may therefore have the potential to control enteric pathogens. Here, we tested if dietary seaweed (Saccharina latissima) supplementation could modulate pig gut health with a specific focus on parasitic helminth burdens, gut microbiota composition, and host immune response during a five week feeding period in pigs co-infected with the helminths Ascaris suum and Oesophagostomum dentatum. We found that inclusion of fermented S. latissima (Fer-SL) at 8% of the diet increased gut microbiota α-diversity with higher relative abundances of Firmicutes, Tenericutes, Verrucomicrobia, Spirochaetes and Elusimicrobia, and lower abundance of Prevotella copri. In the absence of helminth infection, transcription of immune-related genes in the intestine was only moderately influenced by dietary seaweed. However, Fer-SL modulated the transcriptional response to infection in a site-specific manner in the gut, with an attenuation of infection-induced gene expression in the jejunum and an amplification of gene expression in the colon. Effects on systemic immune parameters (e.g. blood lymphocyte populations) were limited, indicating the effects of Fer-SL were mainly localized to the intestinal tissues. Despite previously documented in vitro anti-parasitic activity against pig helminths, Fer-SL inclusion did not significantly affect parasite egg excretion or worm establishment. Collectively, our results show that although Fer-SL inclusion did not reduce parasite burdens, it may modify the gut environment during enteric parasite infection, which encourages continued investigations into the use of seaweeds or related products as novel tools to improve gut health.

Condensed tannins, novel compounds and sources of variation determine the antiparasitic activity of Nordic conifer bark against gastrointestinal nematodes.

The antiparasitic potential of plants could offer a vital solution to alleviating the costs of gastrointestinal nematode (GIN) infections in ruminant production globally. Leveraging known bioactive molecules, however, is complex, where plant species, extraction processes and seasonality impact bioavailability and efficacy. This study assessed the impact of a comprehensive set of factors on the antiparasitic activity of Norwegian conifers to identify bark compounds specific against GIN. Antiparasitic activity was determined using in vitro assays targeting morphologically distinct life stages of ovine GIN: the egg hatch assay and larval motility assay. In depth characterisation of the chemical composition of the bark extracts was carried out using chromatographic separation, UV-absorbance, and molecular mass profiles to identify compounds implicated in the activity. Three key findings emerged: (1) the activity of bark extracts varied markedly from 0 to 100% antiparasitic efficacy, owing to tree species, extraction solvent and seasonality; (2) the GIN exhibited species-and stage-specific susceptibility to the bark extracts; (3) the presence of condensed tannins, amongst other compounds, was associated with anthelmintic activity. These findings add new insights into urgently needed alternative parasite control strategies in livestock.

Assessing welfare risks in unowned unsocialised domestic cats in Denmark based on associations with low body condition score.

BACKGROUND: Populations of unowned unsocialised cats are present worldwide. Generally, there is concern about their welfare. Low body condition score (BCS) is a potentially relevant indicator that is relatively easy to assess: emaciated cats are likely to have welfare problems while thin cats may be at risk of becoming emaciated. The objective of this study was to assess the association of low BSC with a selection of factors relating to the host, disease, and infection in unowned unsocialised domestic cats. We necropsied 598 euthanised unowned unsocialised cats from Denmark. We recorded each cat's age-group, sex, and neuter status, together with its pregnancy status, the season and location of trapping, as well as gross lesions at necropsy. We also tested for feline immunodeficiency virus and feline leukaemia virus, recorded presence of ectoparasites, and a subsample of the cats were also tested for endoparasites. Cats with no or sparse adipose deposits were categorised as having low BCS, and logistic regression was used to determine the factors associated with low BCS. RESULTS: Of the cats, 11.4% had low BCS. Season, age-group and sex were associated with low BCS and confounded potential associations with other variables. Intact adult males and females in spring and early summer were at highest risk of low BCS. When these factors were taken into account, cats with biting lice had 2.8 (95% confidence interval (CI) 1.4-5.4) times higher odds of low BCS, and cats with gastro-intestinal findings (i.e., enlarged mesenteric lymph nodes, abdominal hernia, diarrhoea, obstructive foreign bodies, or diaphragmatic hernia) had 50 (95% CI 10-417) times higher odds of low BCS, than cats with no such findings. Cats with low BCS were primarily adult intact cats with tooth lesions and skin lesions, ear mite infection, and positive test result for feline immunodeficiency virus. CONCLUSIONS: The results highlight associations that can be used to define a risk profile: low BCS, notably in summer-autumn, in an unowned unsocialised cat was associated with underlying, less visible problems. Thus, low BCS can be more than a step towards being emaciated; it can also be an indicator of other underlying welfare problems.

The role of cooking practices in the transmission of the foodborne parasite Taenia solium: A qualitative study in an endemic area of Southern Tanzania.

The pork tapeworm Taenia solium is a zoonotic food-borne parasite endemic in many developing countries causing human cysticercosis and taeniosis as well as porcine cysticercosis. It mainly affects the health of rural smallholder pig farmers and their communities, resulting in lower health status, reduced pork quality, and economic loss due to condemnation of pigs or low pricing of pork. This qualitative study aimed to identify key food related practices linked to consumption of pork at village level, of importance for transmission of taeniosis. We used an interpretivist-constructivist paradigm in a multiple case study of exploratory qualitative research design. Data was acquired through guided and probing interviews with 64 pork cooks, and 14 direct observations in four villages in a T. solium endemic area of Mbeya Region in the Southern Highlands of Tanzania. The study showed that the informants were members of communities of practice through their pork cooking practices, one community of practice for the restaurant cooks and one for the home cooks, learning, sharing, and distributing their cooking skills. Furthermore, the analysis showed that the pork cooks generally had some awareness of there being something undesirable in raw pork, but they had very diverse understandings of what it was, or of its potential harm. Major potential transmission points were identified in restaurants and in home kitchens. It appears that the pork cooks act according to socio-cultural and economic factors guiding them in their actions, including pressure from customers in restaurants, the family values of tradition in the home kitchens, and the culturally guided risk perception and appraisal. These practices might generate potential transmission points. Future research on interventions aimed at preventing the spread of T. solium taeniosis should recognise the importance of tradition and culture in risky food practices.

Evaluation of a novel multiplex qPCR method for rapid detection and quantification of pathogens associated with calf diarrhoea.

AIMS: Diarrhoea is a common health problem in calves and a main reason for use of antimicrobials. It is associated with several bacterial, viral and parasitic pathogens, most of which are commonly present in healthy animals. Methods, which quantify the causative agents, may therefore improve confidence in associating a pathogen to the disease. This study evaluated a novel commercially available, multiplex quantitative polymerase chain reaction (qPCR) assay (Enterit4Calves) for detection and quantification of pathogens associated with calf-diarrhoea. METHODS AND RESULTS: Performance of the method was first evaluated under laboratory conditions. Then it was compared with current routine methods for detection of pathogens in faecal samples from 65 calves with diarrhoea and in 30 spiked faecal samples. The qPCR efficiencies were between 84%-103% and detection limits of 100-1000 copies of nucleic acids per sample were observed. Correct identification was obtained on 42 strains of cultured target bacteria, with only one false positive reaction from 135 nontarget bacteria. Kappa values for agreement between the novel assay and current routine methods varied between 0.38 and 0.83. CONCLUSION: The novel qPCR method showed good performance under laboratory conditions and a fair to good agreement with current routine methods when used for testing of field samples. SIGNIFICANCE AND IMPACT OF STUDY: In addition to having fair to good detection abilities, the novel qPCR method allowed quantification of pathogens. In the future, use of quantification may improve diagnosis and hence treatment of calf diarrhoea.

Administration of spruce bark (Picea abies) extracts in young lambs exhibits anticoccidial effects but reduces milk intake and body weight gain.

BACKGROUND: Eimeria spp. are widespread apicomplexan parasites known to cause coccidiosis in livestock, resulting in reduced animal welfare and productivity, particularly in sheep. The treatment options are limited, and there is an emerging development of resistance against registered pharmaceuticals. Spruce bark is rich in plant secondary metabolites (PSM), such as condensed tannins, which are bioactive compounds previously shown to have antiparasitic activity. Here, we examined the anticoccidial properties of bark extract of Norway spruce (Picea abies) against a field isolate of ovine Eimeria spp. by treating Eimeria-infected pre-ruminant lambs with water-extracted bark daily for 12 days. We hypothesised that the bark extract would reduce the faecal oocyst excretion and, consequently, the severity of diarrhoea. RESULTS: Oral administration of spruce bark extract significantly reduced the excretion of Eimeria oocysts in milk-fed lambs post treatment till the end of the trial 22 days post infection. This difference in oocyst excretion between the treated and the untreated infected animals increased with time. Compared to the untreated and the sham-infected control group, the group treated with bark extract had softer faeces and reduced milk intake during the treatment period. After discontinuing the treatment, the treated animals got a more solid and formed faeces compared to that of the untreated control group, and the milk intake increased to the level of the sham-infected, untreated control group. The bark extract treated animals had a lower body weight and a lower mean daily body weight gain throughout the whole duration of the experiment. CONCLUSIONS: Bark extract from Norway spruce showed marked anticoccidial properties by reducing the faecal oocyst count and associated diarrhoea in young lambs. Simultaneously we experienced detrimental effects of the treatment, displayed as reduced feed intake and daily body weight gain. Therefore, we suggest conducting similar studies with lower bark extract dosage to explore the possibilities of a better trade-off to reduce the negative impact while maintaining the antiparasitic effect.

Extracts of pine bark (Pinus sylvestris) inhibit Cryptosporidium parvum growth in cell culture.

The widespread apicomplexan parasite Cryptosporidium parvum is responsible for severe gastrointestinal disease in humans and animals. The treatment options are limited, and the efficacy of available drugs is low. Bark contains condensed tannins (CT), which are bioactive compounds previously shown to inhibit parasite development. Here, we examined the anti-cryptosporidial properties of bark extract of Scots pine (Pinus sylvestris) against C. parvum by means of an in vitro growth inhibition test. We hypothesised that bark extracts would have dose-dependent inhibitory effects on the development of C. parvum in cell culture.Bark extracts from Scots pine extracted with acetone, methanol, and water as solvents were investigated using human colorectal adenocarcinoma cells infected with C. parvum. Oocysts were inoculated onto the cell monolayer and bark extract was added at seven different concentrations. Parasite growth inhibition was quantified by qPCR.The acetone and methanol extracts demonstrated a sigmoid dose-dependent inhibition of C. parvum. The IC50 values were 244.6 and 279.1 µg dry matter extract/mL, and 25.4 and 24.1 µg CT/mL, for acetone and methanol extracts, respectively. The IC50 for both extracts were similar, both with regard to the dry matter concentration of each extract and to CT concentrations.Given the limited treatment options available for Cryptosporidium spp., the evidence generated in our study encourages further investigation into the in vitro and in vivo effects of pine bark extracts against C. parvum.

Bio-Guided Fractionation and Molecular Networking Reveal Fatty Acids to Be Principal Anti-Parasitic Compounds in Nordic Seaweeds.

Widespread use of antimicrobial drugs has led to high levels of drug-resistance in pathogen populations and a need for novel sources of anti-bacterial and anti-parasitic compounds. Macroalgae (seaweed) are potentially a rich source of bioactive compounds, and several species have traditionally been used as vermifuges. Here, we investigated the anti-parasitic properties of four common cold-water Nordic seaweeds; Palmaria palmata (Rhodophyta), Laminaria digitata, Saccharina latissima and Ascophyllum nodosum (Ochrophyta, Phaeophyceae). Screening of organic extracts against helminths of swine (Ascaris suum) and sheep (Teladorsagia circumcincta) revealed that S. latissima and L. digitata had particularly high biological activity. A combination of molecular networking and bio-guided fractionation led to the isolation of six compounds from extracts of these two species identified in both fermented and non-fermented samples. The six isolated compounds were tentatively identified by using MS-FINDER as five fatty acids and one monoglyceride: Stearidonic acid (1), Eicosapentaenoic acid (2), Alpha-Linolenic acid (3), Docosahexaenoic acid (4), Arachidonic acid (5), and Monoacylglycerol (MG 20:5) (6). Individual compounds showed only modest activity against A. suum, but a clear synergistic effect was apparent when selected compounds were tested in combination. Collectively, our data reveal that fatty acids may have a previously unappreciated role as natural anti-parasitic compounds, which suggests that seaweed products may represent a viable option for control of intestinal helminth infections.

Anthelmintic resistance in small ruminants in the Nordic-Baltic region.

Gastrointestinal nematodes (GIN) in small ruminants result in production losses, and consequently economic losses, and are an animal welfare problem in most countries in the Nordic-Baltic region. Intensive use of anthelmintics to control helminth infections has led to anthelmintic resistance (AR), which has become a major issue in many European countries. Several studies have been performed in countries in the Nordic-Baltic region (e.g. Denmark, Sweden, Norway and Lithuania) showing increasing/emerging levels of AR. The aim of this paper is to provide an overview of the problem of AR on sheep and goat farms in the Nordic-Baltic region. This region has a limited number of registered anthelmintics. However, researchers in this area have discovered some surprising findings, such as ivermectin (IVM) resistance on a farm that had never used IVM. In Sweden there is evidence of macrocyclic lactone (ML)-resistant Haemonchus contortus being introduced with sheep imported from the Netherlands. As elsewhere in the world, the livestock trade appears to be contributing to the spread of AR in the region and isolated cases of multidrug-resistant cases have also been reported. This is surprising given that the frequency of treatments here is much lower than in other countries where sheep production is economically more important. The prevailing nematodes are Haemonchus, Teledorsagia and Trichostrongylus, while on some farms Haemonchus is dominant and clinical haemonchosis has increasingly been observed in recent decades. The reasons for this are unclear, but are probably related to this parasite's propensity to rapidly develop drug resistance and a general lack of awareness of the problem, possibly in combination with global warming and the increased livestock trade within the EU. In addition, domestic interactions through contacts with wildlife ruminants, alpacas may also be a contributing factor for transmission of AR.

Increasing importance of anthelmintic resistance in European livestock: creation and meta-analysis of an open database.

Helminth infections are ubiquitous in grazing ruminant production systems, and are responsible for significant costs and production losses. Anthelmintic Resistance (AR) in parasites is now widespread throughout Europe, although there are still gaps in our knowledge in some regions and countries. AR is a major threat to the sustainability of modern ruminant livestock production, resulting in reduced productivity, compromised animal health and welfare, and increased greenhouse gas emissions through increased parasitism and farm inputs. A better understanding of the extent of AR in Europe is needed to develop and advocate more sustainable parasite control approaches. A database of European published and unpublished AR research on gastrointestinal nematodes (GIN) and liver fluke (Fasciola hepatica) was collated by members of the European COST Action "COMBAR" (Combatting Anthelmintic Resistance in Ruminants), and combined with data from a previous systematic review of AR in GIN. A total of 197 publications on AR in GIN were available for analysis, representing 535 studies in 22 countries and spanning the period 1980-2020. Reports of AR were present throughout the European continent and some reports indicated high within-country prevalence. Heuristic sample size-weighted estimates of European AR prevalence over the whole study period, stratified by anthelmintic class, varied between 0 and 48%. Estimated regional (country) prevalence was highly heterogeneous, ranging between 0% and 100% depending on livestock sector and anthelmintic class, and generally increased with increasing research effort in a country. In the few countries with adequate longitudinal data, there was a tendency towards increasing AR over time for all anthelmintic classes in GIN: aggregated results in sheep and goats since 2010 reveal an average prevalence of resistance to benzimidazoles (BZ) of 86%, macrocyclic lactones except moxidectin (ML) 52%, levamisole (LEV) 48%, and moxidectin (MOX) 21%. All major GIN genera survived treatment in various studies. In cattle, prevalence of AR varied between anthelmintic classes from 0-100% (BZ and ML), 0-17% (LEV) and 0-73% (MOX), and both Cooperia and Ostertagia survived treatment. Suspected AR in F. hepatica was reported in 21 studies spanning 6 countries. For GIN and particularly F. hepatica, there was a bias towards preferential sampling of individual farms with suspected AR, and research effort was biased towards Western Europe and particularly the United Kingdom. Ongoing capture of future results in the live database, efforts to avoid bias in farm recruitment, more accurate tests for AR, and stronger appreciation of the importance of AR among the agricultural industry and policy makers, will support more sophisticated analyses of factors contributing to AR and effective strategies to slow its spread.

TITLE: Importance croissante de la résistance aux anthelminthiques chez les ruminants européens : création et méta-analyse d'une base de données ouverte. ABSTRACT: Les helminthes sont omniprésents dans les systèmes de production de ruminants au pâturage et sont responsables de coûts et de pertes de production importants. La résistance aux anthelminthiques (RA) des parasites est maintenant répandue dans toute l'Europe, bien qu'il existe encore des lacunes dans nos connaissances dans certaines régions et certains pays. La RA est une menace majeure pour la pérennité de la production moderne de ruminants, en diminuant la productivité, en compromettant la santé et le bien-être des animaux, et en augmentant les émissions de gaz à effet de serre au travers d'une augmentation du parasitisme et des intrants agricoles. Une meilleure compréhension de l'étendue de la RA en Europe est nécessaire pour développer et préconiser des approches de lutte antiparasitaire plus durables. Une base de données intégrant des informations publiées et non publiées en Europe concernant la RA des nématodes gastro-intestinaux (NGI) et de la douve du foie (Fasciola hepatica) a été compilée par les membres de l'action européenne COST « COMBAR ¼ (« Combattre la résistance aux anthelminthiques chez les ruminants ¼) et combinée avec les données d'une précédente étude systématique concernant la RA des NGI. Au total, 197 publications sur la RA des NGI étaient disponibles pour analyse, représentant 535 études dans 22 pays et couvrant la période 1980­2020. Des signalements de RA étaient présents sur tout le continent européen et certains rapports indiquaient une forte prévalence nationale. Les estimations heuristiques pondérées par la taille de l'échantillon de la prévalence de la RA en Europe sur toute la période d'étude, stratifiées par classe d'anthelminthiques, variaient de 0 à 48 %. La prévalence régionale (nationale) estimée était très hétérogène, variant entre 0 % et 100 % selon le secteur de l'élevage et la classe d'anthelminthique, et augmentait généralement avec les efforts de recherche dans le pays. Dans les quelques pays disposant de données longitudinales adéquates, il y avait une tendance à l'augmentation de la RA au fil du temps pour toutes les classes d'anthelminthiques des NGI : les résultats agrégés chez les ovins et caprins depuis 2010 révèlent une prévalence moyenne de résistance aux benzimidazoles (BZ) de 86 %, aux lactones macrocycliques sauf moxidectine (ML) de 52 %, au lévamisole (LEV) de 48 % et à la moxidectine (MOX) de 21 %. Tous les genres principaux de NGI ont survécu au traitement dans diverses études. Chez les bovins, la prévalence de la RA variait selon les classes d'anthelminthiques de 0 à 100 % (BZ et ML), 0 à 17 % (LEV) et 0 à 73 % (MOX), et Cooperia et Ostertagia ont survécu aux traitements. Une RA suspectée chez F. hepatica a été signalée dans 21 études portant sur 6 pays. Pour les NGI, et encore plus pour F. hepatica, il y avait un biais d'échantillonnage en faveur des exploitations individuelles suspectées de RA, et l'effort de recherche était biaisé vers l'Europe occidentale et en particulier le Royaume-Uni. La capture continue des résultats futurs dans la base de données, en direct, les efforts pour éviter les biais dans le recrutement des exploitations, des tests plus précis pour la RA et une meilleure appréciation de l'importance de la RA parmi l'industrie agricole et les décideurs politiques, soutiendront des analyses plus sophistiquées des facteurs contribuant à la RA, et des stratégies efficaces pour ralentir sa propagation.

Evidence for mitochondrial pseudogenes (numts) as a source of contamination in the phylogeny of human whipworms.

Trichuris trichiura and T. suis are whipworms of humans and pigs, respectively, but it has recently been suggested that humans may be infected with multiple genotypes or species of Trichuris and cross-infection with Trichuris of pig origin has also been reported. In addition, the species status of Trichuris in non-human primates is unsettled and it is unknown how many whipworm species we share with other primates. Herein, we inferred the phylogeny of Trichuris collected from human, baboon and pig based on nuclear (18S and beta-tubulin) and mitochondrial (cox1) genes and evaluated the use of three PCR linked restriction fragment length polymorphism (PCR-RFLP) to identify worms. We found that all baboon worms clustered with human worms and that all these primate worms are different from T. suis. In general, there was an agreement between the phylogeny established based on the nuclear and mtDNA genes. However, we found evidence for non-targeted cox1 gene amplification for a subset of the human worms and suggest the presence of mitochondrial pseudogenes (numts) of pig cox1 gene in the human Trichuris genome. In conclusion, phylogenetic characterization of human whipworm based on the cox1 gene alone may be problematic without suitable preceded measures to avoid the numts amplification.

Feeding of carob (Ceratonia siliqua) to sheep infected with gastrointestinal nematodes reduces faecal egg counts and worm fecundity.

The present study explored the anthelmintic effects of condensed tannins (CT) in carob (Ceratonia siliqua) pods fed to sheep against gastrointestinal nematodes. Three independent in vivo trials tested whether i) carob pod (CaBP)-containing feed had an anthelmintic effect and if yes, which was the optimal concentration in the diet; ii) whether this effect could be attributed to tannins through the polyethylene glycol (PEG) test and iii) whether there were any synergistic effects when combined with another tannin-containing feed (e.g. sainfoin). In all trials 6-month old nematode-naive lambs, experimentally infected with both Haemonchus contortus and Trichostrongylus colubriformis, were used. Faecal egg counts (FEC) were performed regularly and at the end of each trial adult worm counts (AWC) and female worm fecundity were recorded. In trial 1, 35 lambs (five groups of seven lambs) were fed different CaBP concentrations ranging from 0% to 12 % w/w. FEC declined up to 39.2 % only in the group fed with 12 %CaBP, while a declining trend (P < 0.06) was demonstrated for the AWC of T. colubriformis, which was associated with the increasing concentration of CaBP in feed. Female worm fecundity was reduced in groups fed CaBP for both parasites, however this was only significant for H. contortus (P < 0.001), in a dose dependent manner. In trial 2, four groups of six infected lambs each were used, which received the carob diets CaBP or CaBP + PEG, and the tannin-free diets with or without PEG (C or C + PEG). Results showed that FEC of Groups C, C + PEG, and CaBP + PEG were comparable throughout the trial, while the group receiving only CaBP showed lower FEC from DAY 25 onwards. AWC showed a reduction (67.7 %) only for H. contortus (P < 0.03). Reversal of the anthelmintic effect of CaBP after PEG administration suggested that CT contributed to the anthelmintic action. However, no effect of CaBP was observed on T. colubriformis AWC and on female worm fecundity for both species. Finally, for trial 3 four groups of six lambs each received a diet based on CaBP, sainfoin (S) or a combination (CaBP + S) and were compared to a control (C) diet of lucerne. On DAY 37 FEC values in groups CaBP + S and S tended to be lower compared to the two other groups (C, CaBP), while for AWCs no significant differences were observed for both parasites. The fecundity of H. contortus and T. colubriformis demonstrated significant differences between the treated and control groups, with lower values in the animals receiving CaBP + S. Overall, the results supported the hypothesis that carob had an anthelmintic effect due to its CT, but there was no clear indication of a synergistic effect with sainfoin.

Mebendazole treatment persistently alters the size profile and morphology of Trichuris trichiura eggs.

The soil transmitted whipworm, Trichuris trichiura affects about half a billion people globally. Diagnosis is based on identification of characteristic lemon-shaped eggs in stool samples. Occasionally large Trichuris eggs have been reported and have been ascribed to variation within T. trichiura or zoonotic infection with T. vulpis from dogs. We observed that the egg size profile changed markedly after anthelmintic treatment, and remained so, in a human individual self-infected with T. trichiura. The large eggs were detected with two standard diagnostic methods, Kato-Katz thick smear and salt-flotation (McMaster) method. It is therefore important to bear in mind that the morphology of parasite eggs may vary, e.g. in response to previous drug treatment. Large Trichuris eggs in human stool samples should not be diagnosed as T. vulpis infection without confirmation by other means.

Patterns of Fasciola hepatica infection in Danish dairy cattle: implications for on-farm control of the parasite based on different diagnostic methods.

BACKGROUND: Bovine fasciolosis is an economically important livestock disease in Europe, and represents a particular challenge for organic farms, where cattle are grazed extensively and the use of anthelmintic is limited. A two-year longitudinal study was conducted on two conventional and two organic Danish dairy farms to examine the current temporal trend of F. hepatica infection on-farm, and to gather data of practical relevance for parasite control. Data were collected both at the herd and individual level using currently available diagnostic methods: a commercial serum antibody ELISA, a commercial copro-antigen ELISA, faecal egg counts, and monthly bulk tank milk (BTM) ELISA. The temporal patterns (animal age, farm-level temporal trends and seasonality) in the animal-level test results were analysed by generalised additive mixed models (GAMM). RESULTS: Patterns of infection differed substantially between the farms, due to different grazing management and anthelmintic use. However, animals were first infected at the age of 1.5-2 years (heifers), and most at-risk animals sero-converted in autumn, suggesting that summer infections in snails prevail in Denmark. Our results also suggest that the lifespan of the parasite could be over 2 years, as several cows showed signs of low grade infection even after several years of continuous indoor housing without access to freshly-cut grass. The serum antibody ELISA was able to detect infection first, whereas both copro-antigen ELISA and faecal egg counts tended to increase in the same animals at a later point. Decreasing BTM antibody levels were seen on the two farms that started anthelmintic treatment during the study. CONCLUSIONS: While important differences between farms and over time were seen due to varying grazing management, anthelmintic treatment and climatic conditions, the young stock was consistently seen as the main high-risk group and at least one farm also had suspected transmission (re-infection) within the lactating herd. Careful interpretation of test results is necessary for older cows as they can show persistent infections several years after exposure has stopped. Rigorous treatment regimens can reduce BTM ELISA values, but further research is needed to develop a non-medicinal approach for sustainable management of bovine fasciolosis.

Assessment of the societal cost of Taenia solium in Angónia district, Mozambique.

BACKGROUND: The zoonotic parasite Taenia solium is endemic in Angónia district, Tete province, Mozambique, though the burden of the disease complex is unknown. METHODS: As part of two cross-sectional studies on human and porcine cysticercosis in the area, unique epidemiological and cost data were collected in Angónia district, Mozambique in 2007. These data provided the basis for the assessment of the societal cost of T. solium in the district, which estimates the impact of the disease on human and pig populations and includes both health and economic approaches in the analysis. RESULTS: Approximately 0.7% (95% Uncertainty Interval (UI), 0.4-0.9) and 0.4% (95% UI, 0.2-0.6) of the total population in the district was estimated to suffer from neurocysticercosis (NCC)-associated epilepsy and headache. The estimated average number of disability-adjusted life years (DALYs) due to NCC-associated epilepsy and headache was 6 (95% UI, 4-8) per thousand persons per year. The total annual costs due to T. solium cysticercosis were estimated at 90,000 USD (95% UI, 39,483-201,463) of which 72% (95% UI, 45-91) were costs linked to human cysticercosis and 28% (95% UI, 9.5-55) to pig production losses. The annual economic burden per NCC-associated epilepsy case in the district amounted to 33 USD (95% UI, 10-76). CONCLUSIONS: In this highly endemic area of Mozambique a large number of individuals suffer from symptoms associated with NCC. Healthy years of life are lost and people are left living with disabilities. Infected pork poses a serious risk to the community and affects the economy of smallholder farmers. Cost for treatment and hospitalization of patients with NCC-associated epilepsy, and lack of productivity and inability of suffering patients to work, further hinder socioeconomic development. Feasible solutions framed within a country specific algorithm and stepwise approaches are needed to control the parasite in the country.

Balancing knowledge and basic principles in veterinary parasitology - Competencies for future Danish veterinary graduates.

Veterinary parasitology has always been considered to be relevant and interesting by the Danish veterinary students. Students have to acquaint themselves with many new, small creatures with complicated and varied life cycles and with intricate Latin names that are difficult to pronounce, as only a few parasites have Danish names. In our veterinary curriculum, zoology has disappeared as a discipline, and parasitology has gradually moved from the third year to the beginning of the second year, which implies that, for example, pathology and pharmacology are "unknown fields". The number of contact hours in veterinary parasitology has been gradually cut to 24 lectures (35 min each) and practical exercises (24 h), including 9 h on coprology. The course is taught and examined jointly with bacteriology and virology in a 8-week course. As a comprehensive course, it has become increasingly difficult to get students to acquire enough active knowledge of the most common parasites and an understanding of the basic principles in relation to, for example, transmission and control. Even though information is readily accessible through books and on-line resources, we still believe that a competent clinician should know a range of parasites by heart as an active resource for their work. The dilemma has been tackled (partly) by introducing a veterinary paraclinical refresher course of 18 h (half practicals and half lectures) in the fourth study year. The focus here is on host(herd)-oriented clinical and diagnostic parasitology. The students can also now select a One Health track for six months in which zoonotic parasites are obviously a relevant topic.

Farm-level risk factors for Fasciola hepatica infection in Danish dairy cattle as evaluated by two diagnostic methods.

BACKGROUND: The prevalence of bovine fasciolosis in Denmark is increasing but appropriate guidelines for control are currently lacking. In order to help develop a control strategy for liver fluke, a risk factor study of farm management factors was conducted and the utility of bulk tank milk (BTM ELISA) as a tool for diagnosis in Danish dairy cattle farms was assessed. METHODS: This case-control study aimed to identify farm-level risk factors for fasciolosis in Danish dairy farms (> 50 animals slaughtered in 2013) using two diagnostic methods: recordings of liver condemnation at slaughter, and farm-level Fasciola hepatica antibody levels in BTM. A case farm was defined as having a minimum of 3 incidents of liver condemnation due to liver fluke at slaughter (in any age group) during 2013, and control farms were located within 10 km of at least one case farm and had no history of liver condemnation due to liver fluke during 2011-2013. The selected farmers were interviewed over telephone about grazing and control practices, and BTM from these farms was collected and analysed by ELISA in 2014. The final complete dataset consisting of 131 case and 63 control farms was analysed using logistic regression. RESULTS: Heifers grazing on wet pastures, dry cows grazing on wet pastures, herd size, breed and concurrent beef cattle production were identified as risk factors associated with being classified as a case farm. With the categorised BTM ELISA result as the response variable, heifers grazing on wet pastures, dry cows grazing on wet pastures, and purchase of cows were identified as risk factors. Within the case and control groups, 74.8 and 12.7% of farms were positive for fasciolosis on BTM ELISA, respectively. The differences are likely to be related to the detection limit of the farm-level prevalence by the BTM ELISA test, time span between slaughter data and BTM, and the relatively low sensitivity of liver inspection at slaughter. CONCLUSIONS: Control of bovine fasciolosis in Denmark should target heifers and dry cows through grazing management and appropriate anthelmintic treatment, and BTM ELISA can be a useful diagnostic tool for fasciolosis in Danish dairy farms.

Trichuris suis secrete products that reduce disease severity in a multiple sclerosis model.

Multiple sclerosis is a chronic inflammatory central nervous system (CNS) disease, which affects about 1 in 1000 individuals in the western world. It has been suggested that this relatively high prevalence is linked to a high level of hygiene, i.e. a reduced exposure to various microorganisms, including parasites. Parasites are known to employ different immunomodulatory and antiinflammatory strategies, which enable them to evade destruction by the immune system. We have investigated the immunomodulation by the swine whipworm, Trichuris suis, by measuring the impact of oral administration of T. suis ova as well as of intraperitoneal administration of T. suis excretory/secretory products on the development and progression of experimental autoimmune encephalomyelitis - an animal model that shares clinical and pathological characteristics with multiple sclerosis. Intraperitoneal administration of excretory/secretory products before disease onset, resulted in a significant decrease in disease severity as well as markedly reduced TH1 and TH17 T-cell responses, centrally in the spinal cord as well as in the periphery, i.e. the spleen. Thus, parenteral administration of T. suis-derived products results in a skewing of the immune response with a significant impact on disease severity in a CNS inflammatory disease model.