Helminth parasites in pigs: New challenges in pig production and current research highlights

Helminths in pigs have generally received little attention from veterinary parasitologists, despite Ascaris suum, Trichuris suis, and Oesophagostomum sp. being common worldwide. The present paper presents challenges and current research highlights connected with these parasites. In Danish swine herds, new indoor production systems may favour helminth transmission and growing knowledge on pasture survival and infectivity of A. suum and T. suis eggs indicates that they may constitute a serious threat to outdoor pig production. Furthermore, it is now evident that A. suum is zoonotic and the same may be true for T. suis. With these ‘new’ challenges and the economic impact of the infections, further research is warranted. Better understanding of host–parasite relationships and A. suum and T. suis egg ecology may also improve the understanding and control of human A. lumbricoides and T. trichiura infections. The population dynamics of the three parasites are well documented and may be used to study phenomena, such as predisposition and worm aggregation. Furthermore, better methods to recover larvae have provided tools for quantifying parasite transmission. Thus, an on-going study using helminth naïve tracer pigs has surprisingly demonstrated that soil infectivity with A. suum and T. suis increases during the first 2–3 years after pasture contamination. Though all three helminth species stimulate the Th2 arm of the immune system, Oesophagostomum seems weakly immunogenic, perhaps via specific modulation of the host immune system. A. suum and T. suis potently modulate the host immune response, up-regulating Th2 and down-regulating Th1. As a consequence, A. suum may compromise the efficacy of certain bacterial vaccines, whereas T. suis, which establish only short-term in humans, is a favourite candidate for down-regulating autoimmune Th1-related diseases in man. Some basic research findings have offered new possibilities for future sustainable control measures. For example, the heredity of host resistance to A. suum and T. suis is so high that breeding for resistant pigs may be a possibility. Experimental studies have demonstrated that fermentable dietary carbohydrates have an antagonistic effect on Oesophagostomum and to a lesser extent on T. suis and A. suum, whereas egg-destroying microfungi may be used to inactivate the hard-shelled A. suum and T. suis eggs in the environment. Helminth control in Denmark has previously relied solely on anthelmintic treatment in herds with low helminth transmission. When indoor transmission rates increase, or in outdoor herds with high pasture contamination levels, medication may advantageously be combined with sustainable control measures, such as selected pig genomes, bioactive forages, and egg-destroying microfungi. © 2011 Elsevier B.V. All rights reserved

A phosphorylcholine-containing glycolipid-like antigen present on the surface of infective stage larvae of Ascaris spp. is a major antibody target in infected pigs and humans

BACKGROUND: The pig parasite Ascaris suum plays and important role in veterinary medicine and represents a suitable model for A. lumbricoides, which infects over 800 million people. In pigs, continued exposure to Ascaris induces immunity at the level of the gut, protecting the host against migrating larvae. The objective of this study was to identify and characterize parasite antigens targeted by this local immune response that may be crucial for parasite invasion and establishment and to evaluate their protective and diagnostic potential. METHODOLOGY/PRINCIPAL FINDINGS: Pigs were immunized by trickle infection for 30 weeks, challenged with 2,000 eggs at week 32 and euthanized two weeks after challenge. At necropsy, there was a 100% reduction in worms recovered from the intestine and a 97.2% reduction in liver white spots in comparison with challenged non-immune control animals. Antibodies purified from the intestinal mucus or from the supernatant of cultured antibody secreting cells from mesenteric lymph nodes of immune pigs were used to probe L3 extracts to identify antibody targets. This resulted in the recognition of a 12kDa antigen (As12) that is actively shed from infective Ascaris L3. As12 was characterized as a phosphorylcholine-containing glycolipid-like antigen that is highly resistant to different enzymatic and chemical treatments. Vaccinating pigs with an As12 fraction did not induce protective immunity to challenge infection. However, serological analysis using sera or plasma from experimentally infected pigs or naturally infected humans demonstrated that the As12 ELISA was able to detect long-term exposure to Ascaris with a high diagnostic sensitivity (98.4% and 92%, respectively) and specificity (95.5% and 90.0%) in pigs and humans, respectively. CONCLUSIONS/SIGNIFICANCE: These findings show the presence of a highly stage specific, glycolipid-like component (As12) that is actively secreted by infectious Ascaris larvae and which acts as a major antibody target in infected humans and pigs

Inventering av Gislavedsleden

Över hela västvärlden blir hälsoproblem som hänger ihop med övervikt och för lite rörelse allt vanligare, därför har många länder börjat med att försöka få befolkningen att röra sig mer. Vandring kan vara en lösning på detta problem och därför har man i Jönköpings län börjat se över sitt vandringsledssystem. Gislaveds kommun, i Jönköpings län, har uppmärksammat detta problem och inlett ett arbete med att hitta lösningar för en modernisering och restaurering av Gislavedsleden. Syftet med denna uppsats är att utföra en observationsstudie och analys av Gislavedsleden och framlägga åtgärdsförslag där de behövs. Med hjälp av Rainer Brämers empiriska undersökningar om vandring och vandringsleder, Patrik Grahns parkkaraktärer och Kevin Lynch analysmetod studeras ledens upplevelsevärden. Analysen resulterar i förändringsförslag som kan förbättra ledens upplevelsevärden. I uppsatsen uppmärksammas även att leden inte stödjer rundvandring eller kortare etapper på grund av dålig tillgänglighet, ett problem som leden delar med många andra vandringsleder i Jönköpings län. Även ledens större kontext tas i beaktande så som hur det går att ta sig till och från leden och om den har kapacitet att användas av en större brukargrupp eller på nya sätt. Uppsatsens slutsats visar att ett gemensamt regelverk och en gemensam standard skulle underlätta för att utveckla och förbättra gamla leder eller användas som riktlinjer för skapandet av nya leder. Med en gemensam standard kan vandringsleder länkas samman och vandringen blir en bättre upplevelse i sin helhet. Den använda analysmetoden och de förslag för åtgärder som presenteras för Gislavedsleden, kan användas för vidare arbete eller forskning kring utvecklandet av en nationell standard för svenska vandringsleder

A molecular mechanism directly linking E-cadherin adhesion to initiation of epithelial cell surface polarity

Mechanisms involved in maintaining plasma membrane domains in fully polarized epithelial cells are known, but when and how directed protein sorting and trafficking occur to initiate cell surface polarity are not. We tested whether establishment of the basolateral membrane domain and E-cadherin–mediated epithelial cell–cell adhesion are mechanistically linked. We show that the basolateral membrane aquaporin (AQP)-3, but not the equivalent apical membrane AQP5, is delivered in post-Golgi structures directly to forming cell–cell contacts where it co-accumulates precisely with E-cadherin. Functional disruption of individual components of a putative lateral targeting patch (e.g., microtubules, the exocyst, and soluble N-ethylmaleimide–sensitive factor attachment protein receptors) did not inhibit cell–cell adhesion or colocalization of the other components with E-cadherin, but each blocked AQP3 delivery to forming cell–cell contacts. Thus, components of the lateral targeting patch localize independently of each other to cell–cell contacts but collectively function as a holocomplex to specify basolateral vesicle delivery to nascent cell–cell contacts and immediately initiate cell surface polarity

Molecular Epidemiology of Ascariasis: A Global Perspective on the Transmission Dynamics of Ascaris in People and Pigs

Background The roundworm Ascaris lumbricoides infects 0.8 billion people worldwide, and Ascaris suum infects innumerable pigs across the globe. The extent of natural cross-transmission of Ascaris between pig and human hosts in different geographical settings is unknown, warranting investigation. Methods Adult Ascaris organisms were obtained from humans and pigs in Europe, Africa, Asia, and Latin America. Barcodes were assigned to 536 parasites on the basis of sequence analysis of the mitochondrial cytochrome c oxidase I gene. Genotyping of 410 worms was also conducted using a panel of microsatellite markers. Phylogenetic, population genetic, and Bayesian assignment methods were used for analysis. Results There was marked genetic segregation between worms originating from human hosts and those originating from pig hosts. However, human Ascaris infections in Europe were of pig origin, and there was evidence of cross-transmission between humans and pigs in Africa. Significant genetic differentiation exists between parasite populations from different countries, villages, and hosts. Conclusions In conducting an analysis of variation within Ascaris populations from pig and human hosts across the globe, we demonstrate that cross-transmission takes place in developing and developed countries, contingent upon epidemiological potential and local phylogeography. Our results provide novel insights into the transmission dynamics and speciation of Ascaris worms from humans and pigs that are of importance for control program

En utmaning för interkommunal och multifunktionell landskapsplanering

En utmaning för interkommunal och multifunktionell landskapsplanering: Ett vattendrag i det Skånska landskapet En landskapsplanerare måste ta hänsyn till allt fler aspekter i sin planering. Planeringen ska bland annat baseras på delaktighet av de inblandade, ta hänsyn till miljö, framtidens klimat och det allt större behovet av tätortsnära rekreationsområden. Syftet med detta arbete är att, genom att titta på Segeå se om ett vattendrag kan användas som rekreationsområde som höjer de sociala värdena för tätorterna. Allt fler flyttar till städerna vilket skapar behov av att bygga fler bostäder samtidigt som de nationella miljömålen ställer krav på myllrande våtmarker, levande sjöar och vattendrag, god bebyggd miljö, ett rikt odlingslandskap och mycket mer. Städerna förtätas medan behovet av rekreationsytor blir allt mera påtagligt. Hoppet är att vattendrag kan blir länken mellan stad och land, stadsnära rekreationsområden, men även lösningen till en del av översvämningsproblematiken som följer på framtidens klimatförändringar. Ett stort projekt som ett vattendrag innefattar många inblandade kommuner, markägare och andra intressenter, som kan leda till konflikt och fördröjning i planering och utförande, men det kan också vara en styrka då man delar på kostnaderna. Ett vattendrag har många av de aspekter som anses vara bra för den mentala hälsan samtidigt som den också ger möjligheter till motion. Samtidigt verkar det som om en del klimatanpassningsåtgärder främjar den biologiska mångfalden, samtidigt som de jämnar ut flöden och förskönar vattendragets utseende. Olika styrdokument från kommunerna kan försvåra kommunikationen men samtidigt är visionen den samma vilket kan göra ett sådant projekt mera genomförbart. Omsorgsfull planering och stor transparens är förutsättningen för genomförandet av ett sådant projekt som kan gagna många. Stora infrastrukturella och administrativa gränser kan bilda barriärer som man förhoppningsvis kan övervinna genom tvärvetenskapligt och interkommunalt samarbete. Att genomföra ett projekt av denna storlek är enklare om man delar upp det i olika etapper. För att få många olika infallsvinklar till problematiken ingick det en litteraturstudie, studier av kartmaterialet av området, en fysisk inventering av större delen av ån, kontakt med olika kommuner och Region Skåne samt studier av två referensobjekt. För analysen och presentationen användes GIS.A challenge to intermunicipal and multifunctional landscape planning: A river in the Scanian landscape A landscape planner has to think of many aspects when planning. Planning has to be based on public participation, show consideration to the environment, future climate change and the ever bigger need of having recreation areas near cities. The purpose of this work is to look at the river Segeå, to see if riparian landscape can add to the social values of urban recreation areas. More and more people are moving to the cities which creates the need for building more housing areas at the same time as national policy craves environmental quality objectives such as thriving wetlands, flourishing lakes and streams, a good urban environment and a varied agricultural landscape. Urban densification makes the need for recreation areas more apparent. There is hope that rivers can be the links which connect the cities with the country side, through recreation areas, that also serve as flooding planes for flooding which may be caused by predicted future climate change. A big project such as this contains many municipalities, land owners and other stakeholders who can cause conflicts and slow down planning procedures and the realizations of the plans, but it can also be an advantage when it comes to sharing the costs. Riparian landscape has many of the aspects that are thought to have positive influence on our mental health at the same time as it can be used for exercise. It seems that some of the climatic adaptions considered in this paper are both beneficial for the bio diversity, create a more beautiful river site and at the same time can balance the water flow. The municipalities use different documents as policy instruments for local planning which can complicate communication but their vision for the river seems to be the same which is positive and makes the project possible. Careful planning and transparency are a necessity for the realization of such a project that can be beneficial for many. The implementation of a project this size will be simpler if it is broken up into different stages. To be able to gain as much insight as possible on the subject the study consisted of a wide collection of literature, a study of maps, an onsite visit of almost the entire river area, contact with different municipalities and the Scanian Regional Council and the study of two reference objects. GIS was used for some of the analysis and the presentation of the material

Helminth parasites in pigs: challenges and current research highlights

Helminths in pigs have generally received little attention from veterinary parasitologists, despite Ascaris suum, Trichuris suis, and Oesophagostomum sp. being common worldwide. The present paper presents challenges and current research highlights connected with these parasites. In Danish swine herds, new indoor production systems may favour helminth transmission and growing knowledge on pasture survival and infectivity of A. suum and T. suis eggs indicates that they may constitute a serious threat to outdoor pig production. Furthermore, it is now evident that A. suum is zoonotic and the same may be true for T. suis. With these ‘new’ challenges and the economic impact of the infections, further research is warranted. Better understanding of host-parasite relationships and A. suum and T. suis egg ecology may also improve the understanding and control of human A. lumbricoides and T. trichiura infections. The population dynamics of the three parasites are well documented and may be used to study phenomena, such as predisposition and worm aggregation. Furthermore, better methods to recover larvae have provided tools for quantifying parasite transmission. Thus, an on-going study using helminth naïve tracer pigs has surprisingly demonstrated that soil infectivity with A. suum and T. suis increases during the first 2-3 years after pasture contamination. Though all three helminth species stimulate the Th2 arm of the immune system, Oesophagostomum seems weakly immunogenic, perhaps via specific modulation of the host immune system. Ascaris suum and T. suis potently modulate the host immune response, up-regulating Th2 and down-regulating Th1. As a consequence, A. suum may compromise the efficacy of certain bacterial vaccines, whereas T. suis, which establish only short-term in humans, is a favourite candidate for down-regulating autoimmune Th1-related diseases in man. Some basic research findings have offered new possibilities for future sustainable control measures. For example, the heredity of host resistance to A. suum is so high that breeding for resistant pigs may be a possibility. Experimental studies have demonstrated that fermentable dietary carbohydrates have an antagonistic effect on Oesophagostomum and to a lesser extent on T. suis and A. suum, whereas egg-destroying microfungi may be used to inactivate the hard-shelled A. suum and T. suis eggs in the environment. Helminth control in Denmark has previously relied solely on anthelmintic treatment in herds with low helminth transmission. When indoor transmission rates increase, or in outdoor herds with high pasture contamination levels, medication may advantageously be combined with sustainable control measures, such as selected pig genomes, bioactive forages, and egg-destroying microfungi