Christian Moliin Outzen Kapel

A multiplex PCR for unequivocal differentiation of all encapsulated and non-encapsulated genotypes of Trichinella

We have developed a single PCR test for the simple and unequivocal differentiation of all currently recognised genotypes of Trichilnella. Partial DNA sequence data were generated from internal transcribed spacers ITS1 and ITS2, and from the expansion segment V region of the ribosomal DNA repeat from five species of Trichinella and two additional genotypes, designated T5 and T6. Five different PCR primer sets were identified which, when used simultaneously in a multiplex PCR, produce a unique electrophoretic DNA banding pattern for each species and genotype including three distinct genotypes of Trichinella pseudospiralis. The banding patterns for each parasite genotype consist of no more than two well-defined DNA fragments, except isolates of T. pseudospiralis which generate multiple, closely migrating bands. The expansion segment V-derived primer set contributes at least one fragment to each genotypic pattern and, therefore, functions both as a means for differentiation as well as an internal control for the PCR. The reliability and reproducibility of each DNA banding pattern were verified using multiple geographical isolates of each Trichinella genotype. The technique was developed further to distinguish genotypes at the level of single muscle larvae using a nested, multiplex PCR, whereby the entire internal transcribed spacer region as well as the gap region of the expansion segment V of the large subunit ribosomal DNA are amplified concurrently in a first-round PCR using primer sets specific for each region, followed by the multiplex PCR for final diagnosis.

Trichuris suis ova therapy for allergic rhinitis: A randomized, double-blind, placebo-controlled clinical trial

BACKGROUND Parasitic helminth infections can protect against allergic airway inflammation in experimental models and have been associated with a reduced risk of atopy and a reduced course of asthma in some observational studies. Although no clinical evidence exists to support the use of helminth therapy for allergic disease, the helminth Trichuris suis has demonstrated efficacy in treatment of inflammatory bowel disease. OBJECTIVE To determine efficacy of helminth therapy for allergic rhinitis. METHODS We conducted a double-blind, placebo-controlled, parallel group trial in which 100 subjects age 18 to 65 years with grass pollen-induced allergic rhinitis were randomly assigned to ingest a total of 8 doses with 2500 live T suis ova or placebo with an interval of 21 days. The primary outcome was a change in mean daily total symptom score for runny, itchy, sneezing nose (maximum change, 9.0) or in percentage of well days during the grass pollen season. RESULTS Treatment with T suis ova (N = 49) compared with placebo (N = 47) caused transient diarrhea peaking at day 41 in 33% of participants (placebo, 2%), and increased eosinophil counts (P < .001) and T suis-specific IgE (P < .05), IgG (P < .001), IgG(4) (P < .003), and IgA (P < .001), whereas there was no significant change in symptom scores (0.0; 95% CI, -0.5 to 0.4; P = .87), well days (3%; 95% CI, -9% to 14%; P = .63), total histamine (P = .44), grass-specific IgE (P = .76), or diameter of wheal reaction on skin prick testing with grass (P = .85) or 9 other allergens. CONCLUSION Repeated treatment with the helminth T suis induced a substantial clinical and immunologic response as evidence of infection, but had no therapeutic effect on allergic rhinitis.

Early Divergent Strains of Yersinia pestis in Eurasia 5,000 Years Ago

Summary The bacteria Yersinia pestis is the etiological agent of plague and has caused human pandemics with millions of deaths in historic times. How and when it originated remains contentious. Here, we report the oldest direct evidence of Yersinia pestis identified by ancient DNA in human teeth from Asia and Europe dating from 2,800 to 5,000 years ago. By sequencing the genomes, we find that these ancient plague strains are basal to all known Yersinia pestis. We find the origins of the Yersinia pestis lineage to be at least two times older than previous estimates. We also identify a temporal sequence of genetic changes that lead to increased virulence and the emergence of the bubonic plague. Our results show that plague infection was endemic in the human populations of Eurasia at least 3,000 years before any historical recordings of pandemics.

Host diversity and biological characteristics of the Trichinella genotypes and their effect on transmission.

The host spectra and biological diversity of the Trichinella genotypes are reviewed. While all genotypes appear to reproduce equally well in carnivore hosts, their infectivity and persistence in omnivores and herbivores show remarkable differences. Most of the genotypes found in wildlife have low infectivity for pigs and some persist only for a few weeks; in herbivores this tendency is even more profound, but malnourished, environmentally stressed, or otherwise immuno-suppressed hosts are likely to be more susceptible to Trichinella genotypes that would otherwise cause no, or only low level infection in that particular host species. In the domestic habitat (e.g. domestic pig farms), Trichinella spiralis is found almost exclusively, but in the sylvatic habitat the other Trichinella genotypes have found individual ecological niches. Thus, when environmental stress is limited in the domestic habitat, the high reproductive capacity of T. spiralis has a selective advantage, but in nature, the tolerance of other (sylvatic) genotypes to high and low temperatures and decomposition of host tissue might be more important. Parasite distribution according to muscle appear to be independent of the genotype of Trichinella and predilection sites are primarily determined by host species and secondarily by the age and level of infection. The biological diversity of the Trichinella genotypes should definitely be considered when planning experimental studies, as the uniform high infectivity of all genotypes in carnivores probably make them more suited for comparative studies than rodents.

Trichinella spiralis, T. britovi, and T. nativa : infectivity, larval distribution in muscle, and antibody response after experimental infection of pigs

Abstract The infectivity of Trichinella spiralis, T. nativa, and T. britovi was experimentally compared in pigs. Blood sampling was performed weekly, and muscle juices were obtained at slaughter 10 weeks after inoculation. Muscle larvae were found in all of four pigs inoculated with T. spiralis [mean 190 larvae per gram (lpg)] and in three of four pigs inoculated with T. britovi (mean 7 lpg). No larvae were found in pigs inoculated with T. nativa. For T. spiralis and T. britovi, the neck muscle (m. splenius) appears to be a predilection site in addition to the tongue, the diaphragm, and the jaw. High antibody responses were found in all experimental groups, independent of the antigen used, and even in pigs in which no muscle larvae were recovered. The strong and consistent antibody response found with meat juice indicates the usefulness of this material where a blood sample is not obtainable, e.g. meat samples from wild animals. Immunoblotting (Western blots) on slaughter sera revealed no species specificity when comparing homologous versus heterologous staining.

ASSOCIATIONS BETWEEN TRICHINELLA SPECIES AND HOST SPECIES IN FINLAND

Examination of 627 wild animals—raccoon dogs (Nyctereutes procyonoides), red foxes (Vulpes vulpes), European lynxes (Lynx lynx), brown bears (Ursus arctos), wolves (Canis lupus), and badgers (Meles meles)—revealed Trichinella spp. The prevalence varied according to geographical region of Finland (north; southwest, SW; and southeast, SE) and was the highest among lynxes (70%, SW). The risk of trichinellosis was higher in the SE (odds ratio, OR, 19.4) and SW regions (OR 14.3), as compared with the northern region (OR 1), with no difference between the former 2 regions. Foxes (OR 2.1) and lynxes (OR 1.9) had a higher risk than raccoon dogs (OR 1) of being infected. The distribution of different Trichinella species was evaluated in 87 wild and domestic mammals by multiplex polymerase chain reaction. Trichinella spiralis was detected more often in domestic and synanthropic animals than in sylvatic hosts. Trichinella nativa was detected only in wildlife. Trichinella pseudospiralis was found both in sylvatic and synanthropic hosts. Trichinella britovi was detected only in mixed infections with other Trichinella species. The raccoon dog was the sole host for all 4 Trichinella species and also carried the most intense infections.

Changing dietary habits in a changing world: Emerging drivers for the transmission of foodborne parasitic zoonoses

Changing eating habits, population growth and movements, global trade of foodstuff, changes in food production systems, climate change, increased awareness and better diagnostic tools are some of the main drivers affecting the emergence or re-emergence of many foodborne parasitic diseases in recent years. In particular, the increasing demand for exotic and raw food is one of the reasons why reports of foodborne infections, and especially waterborne parasitosis, have increased in the last years. Moreover increasing global demand for protein of animal origin has led to certain farming practices (e.g. aquaculture) increasing in emerging or developing countries, where health monitoring may not be sufficiently implemented. Therefore, high quality epidemiological data are needed which together with biological, economic, social and cultural variables should be taken into account when setting control programs for these increasingly popular production systems in emerging economies. This review focuses on the dietary, social, economic and environmental changes that may cause an increase in human exposure to foodborne parasites. Some examples illustrating these new epidemiological dynamics of transmission foodborne parasitic disease are presented.

Epidemiology of Echinococcus granulosus in Arbil province, northern Iraq, 1990–1998

During the period 1990-1998, 99 cases of human cystic hydatidosis (12.4 cases per year) were surgically treated at the two main hospitals in Arbil province, northern Iraq, and from this the human occurence for the province was estimated to be 2 per 100,000 inhabitants. In the same area, 1270 sheep, 550 goats and 320 cattle were examined at slaughter for hydatid cysts and prevalence rates were found to be 15.0%, 6.2% and 10.9%, respectively. A decreasing tendency in livestock prevalences was found towards the end of the study period. As in humans, most of the hydatid cysts in livestock were located in the liver. Fertility of sheep cysts, i.e. those containing protoscoleces, was found to be significantly higher (64%) than that of goats (35.7%) and cattle (29.8%). The percentage of fertile cysts containing viable protoscoleces varied between 63 and 82% in the livers and between 72 and 79% in the lungs of the different animal species. A total of 97 stray dogs were examined post-mortem in the years 1991, 1992 and 1998, and Echinococcus granulosus worms were found in the intestines of 48 dogs (49.5%). High worm burdens (> 1000) were observed in 37% of the dogs, medium worm burdens (200-1000) in 41%, and low worm burdens (< 200) in 22%. In 1998, the prevalence of canine echinococcosis (24.3%) was found to be significantly lower than in 1991 (70.4%) and 1992 (60.6%). The prevalence of human hydatidosis did not differ significantly over the years, but the study confirmed that hydatidosis is endemic in northern Iraq, and that housewives, labourers and farmers appear to be at the greatest risk of infection.

Symptoms after Ingestion of Pig Whipworm Trichuris suis Eggs in a Randomized Placebo-Controlled Double- Blind Clinical Trial

Symptoms after human infection with the helminth Trichuris suis have not previously been described. Exposure to helminths has been suggested as immune therapy against allergy and autoimmune diseases. We randomized adults with allergic rhinitis to ingest a dose of 2500 T. suis eggs or placebo every 21 days for 168 days (total 8 doses) in a double-blind clinical trial. In a previous publication, we reported a lack of efficacy and a high prevalence of adverse gastrointestinal reactions. The aim of the present study was to present a detailed description of the adverse event data and post-hoc analyses of gastrointestinal reactions. Adverse events and severity (mild, moderate, severe) were recorded daily by subjects, classified by organ using MedDRA 10.0, and event rates compared between subjects on T. suis treatment vs. subjects on placebo. T. suis-specific serum IgG antibodies were measured by a fluoroenzymeimmunoassay (Phadia ApS). During 163 days complete follow-up, subjects ingesting T. suis eggs (N = 49) had a three to 19-fold higher rate of events (median duration, 2 days) with gastrointestinal reactions (moderate to severe flatulence, diarrhea, and upper abdominal pain) compared with placebo subjects (N = 47). The highest incidence of affected subjects was seen from the first few days and until day 42 (3rd dose): 63% vs. 29% for placebo; day 163: 76% vs. 49% for placebo. Seroprevalences increased concurrently in the T. suis group: Day 59, 50%; day 90, 91%; day 170, 93%. The combined duration of episodes with onset before day 42 was ≤14 days in 80% of affected subjects. Age, gender, total IgE, and recent intestinal symptoms at baseline did not predict gastrointestinal side effects. In conclusion, during the first 2 months, repeated ingestions of 2500 T. suis eggs caused frequent gastrointestinal reactions lasting up to 14 days, whereas 4 months further treatment mainly provoked a subclinical stimulation. Trial registration University hospital Medical Information Network trial registry Reg. no. R000001298, Trial ID UMIN000001070.

Sea ice occurrence predicts genetic isolation in the Arctic fox

Unlike Oceanic islands, the islands of the Arctic Sea are not completely isolated from migration by terrestrial vertebrates. The pack ice connects many Arctic Sea islands to the mainland during winter months. The Arctic fox (Alopex lagopus), which has a circumpolar distribution, populates numerous islands in the Arctic Sea. In this study, we used genetic data from 20 different populations, spanning the entire distribution of the Arctic fox, to identify barriers to dispersal. Specifically, we considered geographical distance, occurrence of sea ice, winter temperature, ecotype, and the presence of red fox and polar bear as nonexclusive factors that influence the dispersal behaviour of individuals. Using distance‐based redundancy analysis and the BIOENV procedure, we showed that occurrence of sea ice is the key predictor and explained 40–60% of the genetic distance among populations. In addition, our analysis identified the Commander and Pribilof Islands Arctic populations as genetically unique suggesting they deserve special attention from a conservation perspective.