Toxoplasma gondii in animals and the environment

Toxoplasma gondii is an obligate intracellular parasite capable of infecting virtually all warm-blooded species, including humans, but cats are the only definitive hosts. Humans or animals acquire T. gondii infection by ingesting food or water contaminated with sporulated oocysts or by ingesting tissue cysts containing bradyzoites. Toxoplasmosis has the highest human incidence among zoonotic parasitic diseases, but it is still considered an underreported zoonosis. The importance of T. gondii primary infection in livestock is related to the ability of the parasite to produce tissue cysts in infected animals, which may represent important sources of infection for humans. Consumption of undercooked mutton and pork are considered important sources of human Toxoplasma gondii. The first aim of this thesis was to develop a rapid and sensitive in- house indirect ELISA for the detection of antibodies against T. gondii in sheep sera. ROC-curve analysis showed high discriminatory power (AUC=0.999) and high sensitivity (99.4%) and specificity (99.8%) of the method. The ELISA was used to test a batch of sheep sera (375) collected in the Forli-Cesena district. The overall prevalence was estimated at 41.9% demonstrating that T. gondii infection is widely distributed in sheep reared in Forli-Cesena district. Since the epidemiological impact of waterborne transmission route of T.gondii to humans is now thought to be more significant than previously believed, the second aim of the thesis was to evaluate PCR based methods for detecting T. gondii DNA in raw and finished drinking water samples collected in Scotland. Samples were tested using a quantitative PCR on 529 bp repetitive elements. Only one raw water sample (0.3%), out of the 358 examined, tested T. gondii positive demonstrating that there is no evidence that tap water is a source of Toxoplasma infection in Scotland.

Role of the environment in the development of canine atopic dermatitis in Labrador and golden retrievers

Canine and human atopic dermatitis are multifaceted diseases whose clinical development may be influenced by several factors, such as genetic background, environment, secondary infections, food and psychological effects. The role of the environment has been extensively examined in humans but remains unclear in dogs. The aim of this study was to examine environmental factors in two genetically close breeds, Labrador and golden retrievers. Using standard criteria, atopic dogs in Switzerland and Germany were selected and compared with healthy individuals. Information on environmental factors was collected using a 46-question survey encompassing date and place of birth, way of life at the breeder's and owner's home, food and treatments. Univariate and multivariate logistic regression were used to assess the association between potential risk factors and disease status. The following parameters were associated with an increased risk of disease development: living in a shed during puppyhood, adoption at the age of 8-12 weeks and washing the dog regularly. In contrast, the following factors were associated with a lower risk: living in a rural environment, living in a household with other animals and walking in a forest. These associations do not prove causality but support the primary hypothesis that certain environmental factors may influence the development of canine atopic dermatitis. Further studies are warranted to confirm these results and conclusions.

Preference for structured environment in zebrafish (Danio rerio) and checker barbs (Puntius oligolepis)

Information about the welfare and husbandry of pet and laboratory fish is scarce although millions of fish are sold in pet shops and used in laboratory research every year. Inadequate housing conditions can cause behavioural problems also in fish since they are complex animals with sophisticated behaviour. In this study, we investigated the influence of environmental complexity on compartment preference and behaviour in zebrafish (Danio rerio) and checker barbs (Puntius oligolepis). For the preference test, large aquaria were divided by two semi-transparent walls of Plexiglas into an empty compartment, a structured compartment enriched with plants and clay pots, and a smaller compartment in-between, where food was provided. For observation, the empty and structured compartments were divided into six zones of similar size by defining three vertical layers and two horizontal areas (back vs. front area). Seven groups of six to nine zebrafish and seven groups of seven or eight checker barbs were observed on four days each (within a time period of ten days) to assess compartment use and activity, and to assess behavioural diversity and use of zones within compartments. Both zebrafish and checker barbs showed a significant preference for the structured compartment. Nevertheless, in neither species did behavioural diversity differ between the empty and structured compartment. Zebrafish used all zones in both compartments to the same extent. Checker barbs, however, used the structured compartment more evenly than the empty compartment, where they mainly used the lower and middle zones. These results suggest that zebrafish and checker barbs have a preference for complex environments. Furthermore, they indicate that the behavioural and ecological needs of fish may vary depending on species, and recommendations for husbandry should be specified at species level. (C) 2011 Elsevier B.V. All rights reserved.

Food-safety hazards in the pork chain in Nagaland, North East India: implications for human health.

Pork occupies an important place in the diet of the population of Nagaland, one of the North East Indian states. We carried out a pilot study along the pork meat production chain, from live animal to end consumer. The goal was to obtain information about the presence of selected food borne hazards in pork in order to assess the risk deriving from these hazards to the health of the local consumers and make recommendations for improving food safety. A secondary objective was to evaluate the utility of risk-based approaches to food safety in an informal food system. We investigated samples from pigs and pork sourced at slaughter in urban and rural environments, and at retail, to assess a selection of food-borne hazards. In addition, consumer exposure was characterized using information about hygiene and practices related to handling and preparing pork. A qualitative hazard characterization, exposure assessment and hazard characterization for three representative hazards or hazard proxies, namely Enterobacteriaceae, T. solium cysticercosis and antibiotic residues, is presented. Several important potential food-borne pathogens are reported for the first time including Listeria spp. and Brucella suis. This descriptive pilot study is the first risk-based assessment of food safety in Nagaland. We also characterise possible interventions to be addressed by policy makers, and supply data to inform future risk assessments.

Campylobacter spp., Yersinia enterocolitica, and Salmonella enterica and their simultaneous occurrence in German fattening pig herds and their environment.

Campylobacter spp., Salmonella enterica, and Yersinia enterocolitica are common causes of foodborne infections in humans with pork as a potential source. Monitoring programs at farm level are, to date, only implemented for S. enterica, while epidemiological knowledge of the other two pathogens is still lacking. This study aimed to assess the pathogen load (in the pigs' environment) in fattening pig herds, their simultaneous occurrence, and the occurrence of Campylobacter spp. and Y. enterocolitica in herds in different Salmonella risk categories. In 50 fattening pig herds in northern Germany, four pooled fecal samples and 10 swab samples from the pigs' direct environment (pen walls, nipple drinkers), indirect environment (hallways, drive boards), and flies and rodent droppings were collected from each herd and submitted for cultural examination. Campylobacter spp. were detected in 38.1% of fecal, 32.7% of direct environment, 5.3% of indirect environment, and 4.6% of flies/pests samples collected, and Y. enterocolitica in 17.1, 8.1, 1.2, and 3.1% and S. enterica in 11.2, 7.7, 4.1, and 1.5%, respectively. For Campylobacter spp., Y. enterocolitica, and S. enterica, 80, 48, and 32% of herds were positive, respectively; 22 herds were positive for both Campylobacter spp. and Y. enterocolitica, 12 for Campylobacter spp. and S. enterica, and 7 for Y. enterocolitica and S. enterica. There was no significant association between the pathogens at herd level. Campylobacter spp. and Y. enterocolitica were found more often in samples from the low Salmonella risk category (odds ratio, 0.51; confidence interval, 0.36 to 0.73, and 0.3, 0.17 to 0.57), and this was also the case for Y. enterocolitica at herd level (odds ratio, 0.08; confidence interval, 0.02 to 0.3). This study provides evidence that the pigs' environment should be accounted for when implementing control measures on farms against Campylobacter spp. and Y. enterocolitica. An extrapolation from the current Salmonella monitoring to the other two pathogens does not seem feasible.

Weeds and endangered herbs have unforeseen dispersal helpers in the agri-environment: gastropods and earthworms

Agri-environmental schemes involving organic farming or set-aside management aim at promoting biodiversity and restoring ecosystem functioning in agrarian landscapes. Application of pesticides in these crop fields is strongly regulated facilitating the spread of weeds but also allowing for the establishment of endangered herbs and a variety of animals.Recent studies found gastropods and earthworms to be legitimate dispersers of seeds of wild plants. We assumed that both groups also playa significant role in the spread and establishment of wild plants within crop fields. Therefore, we are conducting a series of experiments in three different study systems on (1) the role of earthworms and gastropods as dispersers of rare herbs and weeds in an organic rye field in Germany, (2) the seed feeding behavior of gastropods of plants sown in fallow ground in Switzerland, and (3) weed dispersal in irrigated rice fields by golden apple snails in the Philippines.

A Multidisciplinary Team Experience with Food Insecurity & Failure to Thrive

Food insecurity (FI) affects millions of people in the United States and is associated with medical problems, as well as poorer physical and emotional-behavioral adjustment. Failure to thrive is a condition where children fail to gain an appropriate amount of weight, and it can cause long-term effects on cognitive and psychomotor development. While the extent to which FI may contribute to FTT is unclear, FI may contribute both directly through inadequate caloric or nutrient intake and indirectly through increased family stress, parental depression and a chaotic family environment. We present an overview of how FI and FTT may interact, followed by a case study from our multidisciplinary clinic for children with FTT. The importance of screening for FI as well as FTT is discussed. We describe ways for individuals, organizations, and agencies to help reduce the effects of FI in both individuals and their communities.

Occurrence and Genetic Characteristics of Third-Generation Cephalosporin-Resistant Escherichia coli in Swiss Retail Meat

Prevalence and genetic relatedness were determined for third-generation cephalosporin-resistant Escherichia coli (3GC-R-Ec) detected in Swiss beef, veal, pork, and poultry retail meat. Samples from meat-packing plants (MPPs) processing 70% of the slaughtered animals in Switzerland were purchased at different intervals between April and June 2013 and analyzed. Sixty-nine 3GC-R-Ec isolates were obtained and characterized by microarray, PCR/DNA sequencing, Multi Locus Sequence Typing (MLST), and plasmid replicon typing. Plasmids of selected strains were transformed by electroporation into E. coli TOP10 cells and analyzed by plasmid MLST. The prevalence of 3GC-R-Ec was 73.3% in chicken and 2% in beef meat. No 3GC-R-Ec were found in pork and veal. Overall, the blaCTX-M-1 (79.4%), blaCMY-2 (17.6%), blaCMY-4 (1.5%), and blaSHV-12 (1.5%) β-lactamase genes were detected, as well as other genes conferring resistance to chloramphenicol (cmlA1-like), sulfonamides (sul), tetracycline (tet), and trimethoprim (dfrA). The 3GC-R-Ec from chicken meat often harbored virulence genes associated with avian pathogens. Plasmid incompatibility (Inc) groups IncI1, IncFIB, IncFII, and IncB/O were the most frequent. A high rate of clonality (e.g., ST1304, ST38, and ST93) among isolates from the same MPPs suggests that strains persist at the plant and spread to meat at the carcass-processing stage. Additionally, the presence of the blaCTX-M-1 gene on an IncI1 plasmid sequence type 3 (IncI1/pST3) in genetically diverse strains indicates interstrain spread of an epidemic plasmid. The blaCMY-2 and blaCMY-4 genes were located on IncB/O plasmids. This study represents the first comprehensive assessment of 3GC-R-Ec in meat in Switzerland. It demonstrates the need for monitoring contaminants and for the adaptation of the Hazard Analysis and Critical Control Point concept to avoid the spread of multidrug-resistant bacteria through the food chain.

Ethiopia's Food Reserve Policies and Practice

Ethiopia has for a long time been one of the world’s most food-insecure countries. Efforts by the government and a multitude of sponsors including NGOs have developed an array of institutions and instruments to mitigate the negative impact of production and supply disruptions. Public stockpiles are one such tool, the use of which is rapidly increasing worldwide. This brief field study examines the Ethiopian policies and practice in context, including various instruments operated by farmers, processors and traders. The study finds that the multiple objectives assigned to food reserves as well as the present management structure may not be well-suited at a time of high world market prices and when international food aid is dwindling, and as the international regulatory trade and investment environment remains a matter of unfinished business from a global food security perspective. A comprehensive study of various options for improvements would lay out policy alternatives for public authorities and stakeholders.

Erosion in relation to nutrition and the environment.

When considering the erosive potential of a food or drink, a number of factors must be taken into account. pH is arguably the single most important parameter in determining the rate of erosive tissue dissolution. There is no clear-cut critical pH for erosion as there is for caries. At low pH, it is possible that other factors are sufficiently protective to prevent erosion, but equally erosion can progress in acid of a relatively high pH in the absence of mitigating factors. Calcium and phosphate concentration, in combination with pH, determine the degree of saturation with respect to tooth minerals. Solutions supersaturated with respect to enamel or dentine will not cause them to dissolve, meaning that given sufficient common ion concentrations erosion will not proceed, even if the pH is low. Interestingly, the addition of calcium is more effective than phosphate at reducing erosion in acid solutions. Today, several calcium-enriched soft drinks are on the market, and acidic products with high concentrations of calcium and phosphorus are available (such as yoghurt), which do not soften the dental hard tissues. The greater the buffering capacity of the drink or food, the longer it will take for the saliva to neutralize the acid. A higher buffer capacity of a drink or foodstuff will enhance the processes of dissolution because more release of ions from the tooth mineral is required to render the acid inactive for further demineralization. Temperature is also a significant physical factor; for a given acidic solution, erosion proceeds more rapidly the higher the temperature of that solution. In recent years, a number of interesting potentially erosion-reducing drink and food additives have been investigated.

Swiss Policies for more Food Security

Resource-poor yet blissful Switzerland is also one of the most food-secure countries in the world: there are abundant food supplies, relatively low retail prices in terms of purchasing power parity, with few poverty traps. Domestic production covers 70% of net domestic consumption. A vast and efficient food reserve scheme insures against import disruptions. Nonetheless, the food security contribution by the four sectoral policies involved is mutually constrained: our agriculture is protected by the world’s highest tariffs. Huge subsidies, surface payments, and some production quotas substitute market signals with rent maximisation. Moreover, these inefficiencies also prevent trade and investment policies which would keep markets open, development policies which would provide African farmers with the tools to become more competitive, and supply policies which would work against speculators. The paralysing effect of Swiss agricultural policies is exacerbated by new “food security subsidies” in the name of “food sovereignty” while two pending people’s initiatives might yet increase the splendid isolation which in effect reduce Swiss farmer competitiveness and global food security. Is there a solution? Absent a successful conclusion of the Doha Round (WTO) or a Transatlantic Trade and Investment Partnership Agreement (TTIP) further market openings and a consequent “recoupling” of taxpayer support to public goods production remain highly un-likely. To the very minimum Switzerland should resume the agricultural reform process, join other countries trying to prevent predatory behaviour of its investors in developing countries, and regionalise its food reserve.

Cross-cultural equivalence and associations among food insecurity and parental influences of children's fruit and vegetable consumption

Over the past several decades, the prevalence of obesity has dramatically increased. Cause for concern has increased because overweight and obesity are major contributors to morbidity and mortality. Intervention research aimed at reducing the prevalence of obesity has identified the family, specifically the parent, as a key component of the home environment. However, findings from dietary behavior change interventions have been disheartening because few studies have reported meaningful change, suggesting methodological and/or measurement issues within the intervention process. A lack of appropriate mediators and cross-cultural equivalence may partially explain the reason for little change.^ The study aims were to (1) evaluate the psychometric properties and assess the cross cultural equivalence of the Food Insecurity Scale (paper 1) and the modified Parent Feeding Practices Questionnaire (paper 2) and to assess the overall relationships among food insecurity, parent mediators, and parent behaviors towards children's dietary behavior (paper 3) through structural equation modeling and tests of invariance. The study aims were accomplished through conducting secondary analyses using baseline data from English- and Spanish-speaking Hispanic women who participated in the Healthy Families: Step by Step (BHF) study.^ Results indicated that although the FIS and the mPFPQ exhibited sound psychometric properties, the instruments exhibited a lack of invariance across language spoken groups. The lack of invariance was more pronounced in the FIS. Results also supported the theoretical framework identifying parent's perceived barriers and self-efficacy as mediators of parent's behaviors toward improving children's health eating. Results did not suggest that the relationships were moderated by food insecurity.^ In conclusion, the identification of differential item functioning in food insecurity and parent feeding practices may be beneficial in enhancing tailored interventions through the incorporation of cultural differences into the change mechanisms. However, future research needs to be conducted to determine if the lack of invariance demonstrates the existence of item bias or if it is a reflection of true difference among the language spoken groups. Additionally, obesity intervention studies targeting parent/family barriers and parent self-efficacy to provide/encourage healthy diets may result in an increase in parent behaviors which promote healthy eating behaviors among children. Future research should also examine a more complete causal pathway to determine whether parental changes in the mediators ultimately lead to an increase in healthy dietary behavior among children.^

Lipid, carbon and nitrogen content and fatty acid composition of Temora longicornis females and different food species during the experiment

Temora longicornis, a dominant calanoid copepod species in the North Sea, is characterised by low lipid reserves and high biomass turnover rates. To survive and reproduce successfully, this species needs continuous food supply and thus requires a highly flexible digestive system to exploit various food sources. Information on the capacity of digestive enzymes is scarce and therefore the aim of our study was to investigate the enzymatic capability to respond to quickly changing nutritional conditions. We conducted two feeding experiments with female T. longicornis from the southern North Sea off Helgoland. In the first experiment in 2005, we tested how digestive enzyme activities and enzyme patterns as revealed by substrate SDS-PAGE (sodium dodecylsulfate polyacrylamide gel electrophoresis) responded to changes in food composition. Females were incubated for three days fed ad libitum with either the heterotrophic dinoflagellate Oxyrrhis marina or the diatom Thalassiosira weissflogii. At the beginning and at the end of the experiment, copepods were deep-frozen for analyses. The lipolytic enzyme activity did not change over the course of the experiment but the enzyme patterns did, indicating a distinct diet-induced response. In a second experiment in 2008, we therefore focused on the enzyme patterns, testing how fast changes occur and whether feeding on the same algal species leads to similar patterns. In this experiment, we kept the females for 4 days at surplus food while changing the algal food species daily. At day 1, copepods were offered O. marina. On day 2, females received the cryptophycean Rhodomonas baltica followed by T. weissflogii on day 3. On day 4 copepods were again fed with O. marina. Each day, copepods were frozen for analysis by means of substrate SDS-PAGE. This showed that within 24 h new digestive enzymes appeared on the electrophoresis gels while others disappeared with the introduction of a new food species, and that the patterns were similar on day 1 and 4, when females were fed with O. marina. In addition, we monitored the fatty acid compositions of the copepods, and this indicated that specific algal fatty acids were quickly incorporated. With such short time lags between substrate availability and enzyme response, T. longicornis can successfully exploit short-term food sources and is thus well adapted to changes in food availability, as they often occur in its natural environment due seasonal variations in phyto- and microzooplankton distribution.