Abstract 492: Docosahexaenoic Acid-Enriched and Oleic Acid-Enriched Canola Oils Reduce Whole Blood Nuclear Factor Kappa-B Gene Expression in Men and Women with Abdominal Obesity

Introduction

As part of the large Canola Oil Multicenter Intervention Trial (COMIT) study, we have recently shown that consumption of a canola oil enriched with docosahexaenoic acid (DHA) under strictly controlled feeding conditions exerts anti-inflammatory effects compared with a control diet rich in linoleic acid (LA) and a diet rich in flax oil and alpha-linolenic acid (ALA).

Objective

In this study, we have investigated the impact of different oils containing various amounts of ALA, LA, oleic acid (OA) and DHA on the expression of key pro- and anti-inflammatory genes in a subset of adults having participated in COMIT.

Methods

COMIT is a randomized, crossover controlled full feeding trial involving 118 men and women with abdominal obesity and at least one other component of the metabolic syndrome who consumed 5 experimental isoenergetic diets (15.5% protein; 35.7% fat; 50.6% carbohydrate) for 4 weeks each. Here we report the impact of 4 of those 5 diets, which provided 60 g/3000 kcal of different oils: 1- High LA corn/safflower oil (CONTROL, 10.6 g OA; 0.2 g ALA; 41.6 g LA), 2- High ALA flax/safflower oil (FLAX, 10.7 g OA; 19.2 g ALA; 22.5 g LA), 3- High oleic canola (HO-CAN, 42.8 g OA; 1.4 g ALA; 8.8 g LA), 4- High DHA canola (DHA-CAN, 37.9 g OA; 1.2 g ALA; 7.6 g LA; 3.5 g DHA). Inflammatory genes expression in whole blood cells was assessed by real-time polymerase chain reaction from samples collected at the end of each diet in a random subset of 10 individuals (6 men, 4 women).

Results

DHA-CAN lowered the mRNA expression of the nuclear transcription factor kappa-B (NF-[[Unable to Display Character: к]]B) compared with CONTROL (-15.2%, P =0.07) and FLAX (-22.4%, P =0.007). NF-[[Unable to Display Character: к]]B gene expression was also lower after HO-CAN compared with FLAX (-16.5%, P =0.02). There was no apparent between-diet difference in mRNA expression of other inflammatory genes (interleukin (IL)-18, IL-1β, tumor necrosis factor-α) and transcription factors (natriuretic peptide receptor C).

Conclusions

Data from this controlled feeding study suggest that anti-inflammatory effects of a DHA-enriched canola oil and oleic acid-enriched canola oil compared with polyunsaturated fatty acids from plant sources are mediated, at least partly, through an alteration in the NF-[[Unable to Display Character: к]]B pathway.

Repeated high-intensity exercise in a professional rugby league

The primary aim of this study was to identify and describe the frequency and duration of repeated high-intensity exercise (RHIE) bouts in Australian professional rugby league (National Rugby League) and whether these occurred at critical times during a game. Time motion analysis was used during 5 competition matches; 1 player from 3 positional groups (hit-up forward, adjustable, and outside back) was analyzed in each match. The ranges of RHIE bouts for the 3 positional groups were hit-up forwards 9-17, adjustables 2-8, and outside backs 3-7. Hit-up forwards were involved in a significantly greater number of RHIE bouts (p < 0.05) and had the shortest average recovery (376 ± 205 seconds) between RHIE bouts. The single overall maximum durations of RHIE bouts for the hit-up forwards, the adjustables, and the outside backs were 64, 64, and 49 seconds. For all groups, 70% of the total RHIE bouts occurred within 5 minutes prior of a try being scored. The present data show that the nature of RHIE bouts was specific to playing position and occurred frequently at critical times during the game. These results can be used to develop training programs that mimic the 'worst case scenarios' that elite rugby league players are likely to encounter.

Australian dingoes are definitive hosts of Neospora caninum

To provide objective data on the potential role of dingoes (Canis lupus dingo) in the life cycle of Neospora caninum in Australia, the production of N. caninum oocysts by experimentally infected canids was investigated. Three dingo pups raised in captivity and three domestic dogs were fed tissue from calves infected with an Australian isolate of N. caninum, Nc-Nowra. Oocysts of N. caninum, confirmed by species-specific PCR, were shed in low numbers by one dingo pup at 12-14 days p.i. The remaining animals did not shed oocysts. Furthermore, the blood from two out of three dingoes tested positive for DNA of N. caninum using PCR tests at 14 and 28 days p.i. Oocyst shedding from the intestinal tract of a dingo demonstrates that dingoes are definitive hosts of N. caninum and horizontal transmission of N. caninum from dingoes to farm animals and wildlife may occur in Australia.

Encroachment of Echinococcus granulosus into urban areas in eastern Queensland, Australia

OBJECTIVE

To investigate the prevalence of Echinococcus granulosus in wild dogs (dingos and dingo-domestic dog hybrids) living in and around human habitation on Fraser Island and in townships of the Maroochy Shire, on Queensland's Sunshine Coast, Australia.

DESIGN

Wild dogs were humanely killed on Fraser Island and in the Maroochy Shire because they were deemed a potential danger to the public. Their intestines were collected and the contents examined for intestinal parasites.

PROCEDURE

Intestines were removed as soon after death as possible, packed in plastic bags and kept frozen until examination. The intestinal contents were washed, sieved and examined microscopically for the presence of helminths, which were identified and counted.

RESULTS

Intestines from 108 wild dogs, 7 foxes and 18 Fraser Island dingoes were examined. Echinococcus granulosus was only present in the wild dogs from Maroochy Shire (46.3%) with worm burdens of between 30 and 104,000. Other helminths included Spirometra erinacei, Dipylidium caninum, Taenia spp., Ancylostoma caninum and Toxocara canis. Two specimens of a trematode (Haplorchinae sp.) usually found infecting fish and seabirds were recovered from a Fraser Island dingo.

CONCLUSION

Dingoes on Fraser Island are not infected with E. granulosus and do not pose a hydatid disease public health risk to residents or visitors. However, wild dogs examined from the Maroochy Shire do present a potential hydatid disease public health risk.

Evaluation of three PCR assays for the identification of the sheep strain (genotype 1) of Echinococcus granulosus in canid feces and parasite tissues

The performance of 3 PCR assays for the identification of the G1 sheep genotype of Echinococcus granulosus was evaluated using tissue and canid fecal samples. The "Dinkel" and "Stefanić" primers were the most sensitive in detecting E. granulosus DNA in feces of necropsied dogs (73.7% and 100%, respectively). The "Abbasi" primers detected 52.6% of E. granulosus infected dogs but were the most species-specific, cross-reacting only with Echinococcus shiquicus (tissue 90.9%; feces 75%). The Stefanić primers were the least specific (tissue, 27.3%; feces, 25%) for E. granulosus. The Dinkel primers also showed inter-species cross-reactivity (tissue, 63.6%; feces, 100%) but were found to be strain-specific for the E. granulosus G1 sheep genotype. Improvement of PCR tests for Echinococcus species and subspecific variants should rely on the use of less-conserved genes and development of protocols that improve the quality and quantity of DNA extracted from feces.

Echinococcus granulosus: variability of the host-protective EG95 vaccine antigen in G6 and G7 genotypic variants

Cystic hydatid disease in humans is caused by the zoonotic parasite Echinococcus granulosus. As an aid to control transmission of the parasite, a vaccine has been produced for prevention of infection in the parasite's natural animal intermediate hosts. The vaccine utilizes the recombinant oncosphere protein, EG95. An investigation into the genetic variability of EG95 was undertaken in this study to assess potential antigenic variability in E. granulosus with respect to this host-protective protein. Gene-specific PCR conditions were first established to preferentially amplify the EG95 vaccine-encoding gene (designated eg95-1) from the E. granulosus genome that also contains several other EG95-related genes. The optimized PCR conditions were used to amplify eg95-1 from several parasite isolates in order to determine the protein-coding sequence of the gene. An identical eg95-1 gene was amplified from parasites showing a G1 or G2 genotype of E. granulosus. However, from isolates having a G6 or G7 genotype, a gene was amplified which had substantial nucleotide substitutions (encoding amino acid substitutions) compared with the eg95 gene family members. The amino acid substitutions of EG95 in the G6/G7 genotypes may affect the antigenicity/efficacy of the EG95 recombinant antigen against parasites of these genotypes. These findings indicate that characterization of eg95 gene family members in other strains/isolates of E. granulosus may provide valuable information about the potential for the EG95 hydatid vaccine to be effective against E. granulosus strains other than the G1 genotype.

Precocious development of hydatid cysts in a macropodid host

This study describes the pathological changes associated with an experimental infection of captive wallabies with Echinococcus granulosus. Adult and juvenile tammar wallabies (Macropus eugenii) were infected orally with 0, 1,000, 2,500 or 8,000 E. granulosus eggs. Lung cyst progression was monitored by chest radiography every 4 months until 16 months p.i. Animals were necropsied from 9 to 16 months after infection. Cysts were detected radiographically from 4 months onwards. The number of cysts per animal varied from one to 10 and the majority (36/40) of cysts established in the lungs. Infection rate was low (35.5%), but cyst development was more rapid and onset of fertility much earlier than has been recorded in sheep. Cyst growth resulted in loss of functional lung capacity, up to an estimated 28% within 14 months of infection. Degenerative changes in cysts were less common in tammars than has been reported in sheep, with gross degeneration of cysts identified in only two animals. Complications associated with lung cyst development included fatal anaphylaxis, pneumothorax and atelectasis. Seven of the 11 infected tammars died or were euthanased as a result of infection during the experiment. From the parasite's perspective, infection of this host allows a shortened life cycle and correspondingly greater biotic potential. We believe this is the first published study that demonstrates the susceptibility of tammar wallabies to hydatid disease and confirms their suitability as a laboratory model for studying the disease in macropodids.

Milbemycin oxime in a new formulation, combined with praziquantel, does not reduce the efficacy of praziquantel against Echinococcus multilocularis in cats

Twenty European domestic cats were each infected with 15,000 protoscoleces of Echinococcus multilocularis extracted from metacestodes grown in experimentally infected common voles (Microtus arvalis). Sixteen days after infection, ten cats were treated with a broad-spectrum anthelmintic and acaricide comprising praziquantel and milbemycin oxime. Five days later treated and untreated cats were euthanized and the intestine examined for E. multilocularis. Five of ten untreated cats were infected with E. multilocularis with worm burdens ranging from 235 to 1920 worms per cat. No E. multilocularis were recovered from any of the treated cats. This study has demonstrated that this new combination broad spectrum anthelmintic and acaricide for cats is highly efficacious against E. multilocularis and the relevance of this is discussed.

Emergence/re-emergence of Echinococcus spp.--a global update

This review provides an update of the biological aspects of the genus Echinococcus and focuses on newly recognized endemic areas. Infection with the intermediate cystic stage of all species of Echinococcus causes disease and incapacity in animals and humans, and in the most serious cases, death of the host. Transmission of Echinococcus to new continents has occurred during European colonisation and the parasite has often taken advantage of Echinococcus-naive wildlife populations in these new environments, incorporating them into its transmission pattern. Echinococcus granulosus consists of a complex of 10 strains. Host specificities of these strains have important implications for transmission and control. As a result of human behaviour and/or political instability in a number of countries Echinococcus is re-emerging as an important public health issue. The importance of wildlife reservoirs in perpetuating transmission and as a source of infection for domestic animals and humans is addressed. The review also refers to the transmission pattern of a recently described new species, Echinococcus shiquicus, from China.

Detection of Echinococcus granulosus coproantigens in faeces from naturally infected rural domestic dogs in south eastern Australia

OBJECTIVE

To investigate the occurrence of Echinococcus granulosus in rural domestic dogs in farming areas around Yass, New South Wales, and Mansfield and Whitfield, Victoria.

DESIGN

Faeces were collected per-rectally from farm dogs voluntarily presented by their owners in four farming districts in New South Wales and two in Victoria.

PROCEDURE

Faeces were collected in the field, an extract prepared from each sample and E granulosus coproantigens detected in an ELISA. Farmers were also questioned about their dog feeding and worming practices.

RESULTS

Echinococcus granulosus coproantigens were detected in 99 of 344 dogs (29%) from 95 farms in south eastern New South Wales and 38 of 217 dogs (17.5%) from 43 farms in Victoria. Cross-reactions between E granulosus coproantigen trapping antibody and coproantigens in faeces from dogs monospecifically infected with other species of intestinal helminthes (Taenia ovis, T hydatigena, T pisiformis, Spirometra ericacei, Dipylidium caninum, hookworm, Toxocara canis, Trichuris vulpis) were not evident. Dietary and worming data revealed many owners fed raw meat and occasionally offal from domestic livestock and wildlife to their dogs and few owners wormed their dogs frequently enough to preclude the chance of patent E granulosus being present in their dogs.

CONCLUSION

Echinococcus granulosus occurs commonly in rural dogs in south eastern Australia and an education program promoting the public health importance of responsible management of rural dogs is urgently needed.

Echinococcus granulosus in Australia, widespread and doing well!

Echinococcus granulosus is the only member of the Genus Echinococcus to occur in Australia. The major biomass of E. granulosus occurs in wildlife. The wildlife transmission cycle is predominantly perpetuated via a predator/prey interaction between wild dogs (dingoes and dingo/domestic dog hybrids) and macropodid marsupials (wallabies and kangaroos). Other wildlife hosts include foxes, wombats and feral pigs. This wildlife reservoir for E. granulosus "spills over" to help maintain a domestic cycle through E. granulosus-infected wild dogs defecating on pasture, transmitting infection to livestock and some farmers and hunters feeding hydatid-infected offal of macropodids or feral pigs to domestic dogs. The potential transmission risk to humans using public picnic and camping areas in parks and forests, especially in the southeastern Australia, could be substantially reduced through regular distribution of baits containing praziquantel. Encroachment of wild dogs and foxes into urban centers presents a new potential path of transmission from wildlife to humans.

Evaluation of the efficacy of emodepside+praziquantel topical solution against cestode (Dipylidium caninum, Taenia taeniaeformis, and Echinococcus multilocularis) infections in cats

Emodepside+praziquantel topical solution was developed to provide broad-spectrum anthelmintic activity against gastrointestinal parasites in cats. Eight controlled studies were conducted to evaluate the efficacy of a topical solution of emodepside (3 mg/kg) and praziquantel (12 mg/kg) (Profender, BayerAG, Leverkusen, Germany) against feline infections with three species of cestodes. Studies featured naturally acquired infections of Dipylidium caninum or Taenia taeniaeformis, or experimental infections with Echinococcus multilocularis that were placebo-controlled, randomized and blinded. Cats were euthanatized and necropsied between 2 and 11 days after treatment, depending on the target parasite. The efficacy of emodepside+praziquantel topical solution was 100% against D. caninum and T. taeniaeformis, and 98.5- 100% against E. multilocularis. No significant systemic or local adverse reactions to treatment were noted in cats that received the combination. Topical treatment of cats with emodepside+praziquantel topical solution was safe and highly effective against cestode infections.

Hydatid control in Australia: where it began, what we have achieved and where to from here

Echinococcus granulosus was imported into Australia with domestic livestock about 200 years ago. It spread rapidly through domestic animals and quickly became a public health problem in the new colony. Control was hampered by ignorance of the transmission pattern. The association between metacestodes and tapeworms was not elucidated until 63 years after the arrival of the First Fleet. Australian wildlife were highly susceptible to infection with E. granulosus and wildlife/domestic animal interaction facilated rapid infiltration of wildlife by E. granulosus. The wildlife reservoir has hampered hydatid control campaigns on mainland Australia but successful eradication has been achieved in the island state of Tasmania where there was no wildlife reservoir. The application of a new recombinant vaccine for sheep in control campaigns and the use of praziquantel baits for controlling infection in dingoes around bush campsites and picnic areas is discussed.

The contribution of spotted-tailed quolls (Dasyurus maculatus) to the transmission of Echinococcus granulosus in the Byadbo Wilderness Area, Kosciuszko National Park, Australia

Scats were collected from 19 wild spotted-tailed quolls (Dasyurus maculatus) caught in a region of south-eastern mainland Australia where hydatidosis (Echinococcus granulosus) occurs commonly in swamp wallabies (Wallabia bicolour) and other wildlife. All scats were tested for coproantigens of E. granulosus tapeworms. None of the scats tested had detectable coproantigens of E. granulosus. These data and previous unsuccessful attempts to experimentally infect other species of dasyruid with E. granulosus suggest that spotted-tailed quolls may be refractory to infection with E. granulosus.

Effect of cyclosporin A on the survival and ultrastructure of Echinococcus granulosus protoscoleces in vitro

Surgical treatment of human hydatidsosis involves the use of various scolicidal agents to kill infective Echinococcus granulosus protoscoleces that may disseminate into the peritoneal cavity during surgery and potentially re-infect the patient. Currently, no scolicidal agent is completely effective in killing intracystic protoscoleces in humans. Cyclosporin A (CsA) has previously been found to be lethal for E. granulosus protoscoleces in vitro. In this study, we further assessed the effectiveness of CsA as a scolicidal agent by testing the toxic effect of CsA at higher doses over various time-periods. Experiments were performed on activated and unactivated protoscoleces cultured in nutrient medium or sheep hydatid cyst fluid. All activated protoscoleces were killed following culture in 100 microg/ml of CsA for 3 days and 50 or 20 microg/ml for 5 days. The lethal effect of CsA on unactivated protoscoleces varied but reached 100% over 15 days in culture with 100 or 50 microg/ml of CsA. Pulse treatment of protoscoleces with 50, 20 or 10 microg/ml of CsA for 5 min or 72 h killed all parasites by day 10 and day 5 respectively. Untreated protoscoleces remained greater than 95 % viable for the duration of experiments. Changes in protoscolex ultrastructure induced by treatment with 10 microg/ml of CsA over 10 days in in vitro culture was assessed by TEM. Protoscolex alterations observed in treated parasites included an increase in cellular vacuolization, swelling of mitochondria, rounding of cells, damage to the tegument, decrease in glycogen, a breakdown of the extracellular matrix and an increase in lipid globules. The untreated protoscoleces, by comparison, had few changes during the 10-day culture period with the exception of large amounts of extracellular glycogen observed in the protoscoleces at culture days 7 and 10. From these results, CsA is clearly an effective scolicidal agent in vitro that may have potential application as a new therapeutic agent in the treatment of human hydatid disease.

Transmission ecology of Echinococcus in wild-life in Australia and Africa

Following the introduction of E. granulosus into Australia with domestic animals during European settlement, the parasite quickly became established in the E. granulosus-naive native animals of the continent. The distribution of E. granulosus in wildlife in Australia is restricted by rainfall, but nevertheless the parasite is currently widespread and highly prevalent in many areas including numerous national parks and privately owned farms. The human population of Africa is rapidly increasing resulting in ever more pressure on wild-life populations and habitat. National parks, reserves and conservation areas now provide important tracts of preserved habitat for maintaining populations of wildlife that are also important in the maintenance of E. granulosus. In some parts of Africa, hydatid-infected humans provide a source of E. granulosus infection to wildlife definitive hosts. In many areas felids may also act as important definitive hosts for E. granulosus with the parasite being maintained in a prey/predator relationship between lions and a range of intermediate hosts. Populations of E. granulosus-infected wild-life both in Australia and Africa act as important reservoirs in perpetuating the transmission of E. granulosus to both domestic animals and humans. In Australia, E. granulosus-infected wild-life is infiltrating urban areas and currently represents a potentially important new public health problem.

Echinococcus granulosus in wildlife in and around the Kosciuszko National Park, south-eastern Australia

OBJECTIVE

To investigate the distribution of Echinococcus granulosus in wild dogs and foxes and hydatidosis in wildlife coexisting with foxes and wild dogs in and around Kosciuszko National Park.

DESIGN

Prospective and ad hoc surveys by necropsy of definitive and intermediate hosts.

PROCEDURE

Wild dogs and foxes were trapped at one location in the Kosciuszko National Park and at 7 locations around the periphery of the Park. Feral pigs, macropodid marsupials, wombats, and feral goats were collected at some of the same locations. The animals were humanely killed, their small intestines removed in the field, the contents collected, preserved and examined microscopically. All internal organs of intermediate hosts were examined for hydatid cysts. Unidentified lesions were examined histologically.

RESULTS

Echinococcus granulosus tapeworms were found in wild dogs from all locations. Prevalence ranged up to 100% with worm burdens up to 300,000 worms. Prevalence in foxes ranged up to 50% in animals recovered from 5 locations. The worm burdens were usually less than 50 E. granulosus per fox. Hydatid cysts were found in all macropodid species. Prevalence (69%) and cyst fertility (100%) were highest in swamp wallabies (Wallabia bicolour). Prevalence of cysts in feral pigs ranged up to 49%. Less than 22% of the cysts were fertile. No cysts were found in any of the wombats or feral goats.

CONCLUSION

Echinococcus granulosus occurs commonly in wildlife in and around the Kosciuszko National Park. High numbers of fertile cysts in swamp wallabies, a favoured dietary item for wild dogs in this region, suggests swamp wallabies are pivotal in maintaining transmission. Physical contact with wild dogs and foxes or accidental contact with wild canid faeces is a public health risk.