Detection and Phylogenetic Analysis of Orf Virus and Muskox Rhadinovirus 1 from Muskoxen (Ovibos moschatus) in the Canadian Arctic

Orf virus (genus Parapoxvirus) has been associated with gross skin lesions on muskoxen (Ovibos moschatus) from Victoria Island, Nunavut, Canada, where muskox populations are experiencing population declines. Orf virus causes painful proliferative and necrotizing dermatitis upon viral replication and shedding, which may lead to animal morbidity or mortality through secondary infections and starvation. Herpesvirus, known to cause gross lesions on skin and mucosa during active viral replication, has also been documented in muskoxen but to date has not been associated with clinical disease. Our objective was to characterize the variation of orf virus and herpesvirus in wild muskoxen of the Canadian Arctic. Tissue samples including gross skin lesions from the nose, lips, and/or legs were opportunistically collected from muskoxen on Victoria Island, Nunavut and Northwest Territories, and mainland Nunavut, Canada, from 2015 to 2017. Sampled muskoxen varied in age, sex, location, hunt type, and body condition. Tissues from 60 muskoxen were tested for genetic evidence of orf virus and herpesvirus infection using PCR targeting key viral genes. Tissues from 38 muskoxen, including 15 with gross lesions, were also examined for histological evidence of orf virus and herpesvirus infection. Eleven muskoxen (10 from Victoria Island and one from mainland Nunavut) with gross lesions had microscopic lesions consistent with orf virus infection. Muskox rhadinovirus 1, a gammaherpesvirus endemic to muskoxen, was detected in 33 (55%) muskoxen including 17 with gross lesions. In all tissues examined, there was no histological evidence of herpesvirus-specific disease. Sequencing and characterization of amplified PCR products using phylogenetic analysis indicated that a strain of orf virus, which appears to be unique, is likely to be endemic in muskoxen from Victoria Island and mainland Nunavut. Many of the muskoxen are also subclinically infected with a known muskox-endemic strain of herpesvirus.

Risk factors for Echinococcus multilocularis intestinal infections in owned domestic dogs in a North American metropolis (Calgary, Alberta)

Human alveolar echinococcosis is increasingly documented in Alberta, Canada. Its causative agent, Echinococcus multilocularis (Em), can be transmitted to humans by infected dogs. We assessed the prevalence and associated risk factors for Em infections in domestic dogs in Calgary, Alberta, Canada. In this cross-sectional study that coupled collection and assessment of dog feces with a survey on potential risk factors, 13 of 696 (Bayesian true prevalence, 2.4%; 95% CrI: 1.3-4.0%) individual dogs' feces collected during August and September 2012 were qPCR positive for Em. Sequencing two of these cases indicated that both were from the same Em European strain responsible for human infections in Alberta. Likelihood of intestinal Em was 5.6-times higher in hounds than other breeds, 4.6-times higher in dogs leashed at dog parks than those allowed off-leash, 3.1-times higher in dogs often kept in the backyard during spring and summer months than those rarely in the yard, and 3.3-times higher in dogs living in neighbourhoods bordering Bowmont park than those in other areas of Calgary. This situation warrants surveillance of dog infections as a preventative measure to reduce infections in North America.

Comparative pathogenicity of infectious bronchitis virus Massachusetts and Delmarva (DMV/1639) genotypes in laying hens

Infectious bronchitis (IB) is a highly contagious and acute viral disease of chicken caused by the infectious bronchitis virus (IBV) of the family Coronaviridae. Even with extensive vaccination against IB by the poultry industry, the occurrence of new IBV genotypes is a continuous challenge encountered by the global poultry industry. This experiment was designed to compare the pathogenicity of two IBV strains belonging to Massachusetts (Mass) and Delmarva DMV/1639 genotypes. Specific pathogen-free laying hens were challenged during the peak of production (30 weeks), keeping a mock-infected control group. During 21 days of observation following infection, a significant drop in egg production with miss-shaped and soft shells was observed in the DMV/1639 IBV-infected hens only. The DMV/1639 IBV infected group showed prolonged and higher cloacal viral shedding compared with the Mass IBV-infected group. At the end of the study (21 days post-infection), the viral genome loads in the respiratory, urogenital, and immune tissues were significantly higher in the DMV/1639 IBV-infected group compared with the Mass IBV-infected group. Macroscopic lesions such as distorted ova leading to egg peritonitis were observed only in the DMV/1639 IBV-infected group. Moreover, microscopic lesion scores were significantly higher in the lung, kidney, cecal tonsils, and oviduct of the DMV/1639 IBV-infected group compared with the Mass IBV-infected group. Finally, the apoptosis index in the kidney, ovary, magnum, isthmus, and shell gland was significantly higher in the DMV/1639 IBV-infected group compared with the control and Mass-infected groups. This study examined the pathogenicity of two IBV genotypes that are impacting the layer industry in North America.

Examination of the horizontal gene transfer dynamics of an integrative and conjugative element encoding multidrug resistance in Histophilus somni

Integrative and conjugative elements (ICEs) are self-transferable mobile genetic elements that play a significant role in disseminating antimicrobial resistance between bacteria via horizontal gene transfer. A recently identified ICE in a clinical isolate of Histophilus somni (ICEHs02) is 72 914 base pairs in length and harbours seven predicted antimicrobial resistance genes conferring resistance to tetracycline (tetR-tet(H)), florfenicol (floR), sulfonamide (Sul2), aminoglycosides (APH(3″)-Ib, APH(6)-Id, APH(3')-Ia), and copper (mco). This study investigated ICEHs02 host range, assessed effects of antimicrobial stressors on transfer frequency, and examined effects of ICEHs02 acquisition on hosts. Conjugation assays examined transfer frequency of ICEHs02 to H. somni and Pasteurella multocida strains. Polymerase chain reaction assays confirmed the presence of a circular intermediate, ICE-associated core genes, and cargo genes in recipient strains. Susceptibility testing examined ICEHs02-associated resistance phenotypes in recipient strains. Tetracycline and ciprofloxacin induction significantly increased the transfer rates of ICEHs02 in vitro. The copy numbers of the circular intermediate of ICEHs02 per chromosome exhibited significant increases of ∼37-fold after tetracycline exposure and ∼4-fold after ciprofloxacin treatment. The acquisition of ICEHs02 reduced the relative fitness of H. somni transconjugants (TG) by 28% (w = 0.72 ± 0.04) and the relative fitness of P. multocida TG was decreased by 15% (w = 0.85 ± 0.01).

Knowledge Gaps in the Understanding of Antimicrobial Resistance in Canada

Current limitations in the understanding and control of antimicrobial resistance (AMR) in Canada are described through a comprehensive review focusing on: (1) treatment optimization; (2) surveillance of antimicrobial use and AMR; and (3) prevention of transmission of AMR. Without addressing gaps in identified areas, sustained progress in AMR mitigation is unlikely. Expert opinions and perspectives contributed to prioritizing identified gaps. Using Canada as an example, this review emphasizes the importance and necessity of a One Health approach for understanding and mitigating AMR. Specifically, antimicrobial use in human, animal, crop, and environmental sectors cannot be regarded as independent; therefore, a One Health approach is needed in AMR research and understanding, current surveillance efforts, and policy. Discussions regarding addressing described knowledge gaps are separated into four categories: (1) further research; (2) increased capacity/resources; (3) increased prescriber/end-user knowledge; and (4) policy development/enforcement. This review highlights the research and increased capacity and resources to generate new knowledge and implement recommendations needed to address all identified gaps, including economic, social, and environmental considerations. More prescriber/end-user knowledge and policy development/enforcement are needed, but must be informed by realistic recommendations, with input from all relevant stakeholders. For most knowledge gaps, important next steps are uncertain. In conclusion, identified knowledge gaps underlined the need for AMR policy decisions to be considered in a One Health framework, while highlighting critical needs to achieve realistic and meaningful progress.

The prevalence and levels of enteric viruses in groundwater of private wells in rural Alberta, Canada

The prevalence and levels of enteric viruses in untreated groundwater of private wells used for drinking and/or agricultural practices in rural Alberta were studied using the qPCR panel assay, integrated cell culture with qPCR and cell culture in the volume of 500 liters per sample through serial sampling. Seven viruses were assessed including adenovirus, rotavirus, norovirus, astrovirus, sapovirus, reovirus and JC virus. Five viruses were detected with an overall positive detection rate of 6.33 % (45 of 711 samples). The most frequently detected virus was adenovirus (48.9%, 22/45) followed by rotavirus (44.4%, 20/45), reovirus (20%, 9/45), JC virus (6.7%, 3/45) and norovirus (6.7%, 3/45). There was no significant difference in the positive detection rates, ranging from 1.1% to 3.4% by various well settings used for broiler farms, cow/calf farms, feedlots and rural acreages. Effects of well characteristics (aquifer type, well depth, static level of water, well seal) and well completion lithology on potential viral contamination of groundwater of private wells were also analyzed upon available data. The findings demonstrate that occurrence of enteric viruses is low and viral contamination is sporadic in groundwater of private wells in rural Alberta. Conventional fecal bacterial indicators (coliform and/or E. coli) were not a representative marker for viral contamination in groundwater wells in rural Alberta.

Genetic Characterization of AmpC and Extended-Spectrum Beta-Lactamase Phenotypes in Escherichia coli and Salmonella From Alberta Broiler Chickens

Horizontal gene transfer is an important mechanism which facilitates bacterial populations in overcoming antimicrobial treatment. In this study, a total of 120 Escherichia coli and 62 Salmonella enterica subsp. enterica isolates were isolated from broiler chicken farms in Alberta. Fourteen serovars were identified among Salmonella isolates. Thirty one percent of E. coli isolates (37/120) were multiclass drug resistant (resistant to ≥ 3 drug classes), while only about 16% of Salmonella isolates (10/62) were multiclass drug resistant. Among those, eight E. coli isolates had an AmpC-type phenotype, and one Salmonella isolate had an extended-spectrum beta-lactamase (ESBL)-type beta-lactamase phenotype. We identified both AmpC-type (bla_CMY-2) and ESBL-type (bla_TEM) genes in both E. coli and Salmonella isolates. Plasmids from eight of nine E. coli and Salmonella isolates were transferred to recipient strain E. coli J53 through conjugation. Transferable plasmids in the eight E. coli and Salmonella isolates were also transferred into a lab-made sodium azide-resistant Salmonella recipient through conjugation. The class 1 integrase gene, int1, was detected on plasmids from two E. coli isolates. Further investigation of class 1 integron cassette regions revealed the presence of an aadA gene encoding streptomycin 3’’-adenylyltransferase, an aadA1a/aadA2 gene encoding aminoglycoside 3’’-O-adenyltransferase, and a putative adenylyltransferase gene. This study provides some insight into potential horizontal gene transfer events of antimicrobial resistance genes between E. coli and Salmonella in broiler chicken production.

A knowledge, attitudes, and practices study on ticks and tick-borne diseases in cattle among farmers in a selected area of eastern Bhutan

Livestock farming plays an important role in supporting the livelihood of resource-poor subsistence farmers in Bhutan. However, ticks and tick-borne diseases (TBDs) are one of the major constraints to livestock farming due to their negative effect on health and production. To date, no study has been conducted in Bhutan to assess farmers' knowledge, attitude, and practices (KAP) about ticks and TBDs in cattle, although such information is essential in ensuring the development and adoption of effective prevention and control measures. Therefore, a KAP survey was conducted among 246 cattle owners in the Samkhar sub-district of eastern Bhutan in June 2019, using a structured questionnaire. Based on our scoring criteria, 52% [95%CI: 45.5-58.4] had adequate knowledge about ticks as potential vectors of diseases. Logistic regression analysis showed that the individuals who practiced a stall-feeding system of cattle rearing were 2.8 times [OR = 2.8 (95%CI: 1.66-4.78)] more likely to have adequate knowledge than others. Sixty-eight percent [95%CI: 62.5-74.4] had a favorable attitude toward tick prevention and control programs. Men were 1.95 times [OR = 1.95 (95%CI: 1.09-3.55)] more likely to have a favorable attitude than women, and the individuals who practiced a stall-feeding system were 2.59 times [OR = 2.59 95%CI: 1.45-4.78)] more likely to have a favorable attitude than others, after adjusting for the effect of other variables in the model. Overall, only 38% [95%CI 32.5-45] of the respondents reported tick infestation as one of the most important animal health problems, but 100% reported using acaricides to control ticks in cattle. Despite a high level of acaricide usage, the level of knowledge was low among the farmers interviewed. Findings from this study underline the importance of considering identified knowledge gaps and initiating education efforts to improve the adoption of effective tick prevention and control measures among farmers.

Identification, Distribution, and Habitat Suitability Models of Ixodid Tick Species in Cattle in Eastern Bhutan

Tick infestation is the most reported parasitological problem in cattle in Bhutan. In May and June 2019, we collected ticks from 240 cattle in two districts of Eastern Bhutan. Tick presence, diversity, and infestation prevalence were examined by morphological identification of 3600 live adult ticks. The relationships between cattle, geographic factors, and infestation prevalence were assessed using logistic regression analyses. Habitat suitability for the tick species identified was determined using MaxEnt. Four genera and six species of ticks were found. These were Rhipicephalus microplus (Canestrini) (70.2% (95% confidence interval (CI): 68.7-71.7)), Rhipicephalus haemaphysaloides Supino (18.8% (95% CI: 17.5-20.1)), Haemaphysalis bispinosa Neumann (8.2% (95% CI: 7.3-9.1)), Haemaphysalis spinigera Neumann (2.5% (95% CI: 2-3)), Amblyomma testudinarium Koch (0.19% (95% CI: 0.07-0.4)), and a single unidentified Ixodes sp. Logistic regression indicated that the variables associated with infestation were: longitude and cattle age for R. microplus; latitude for R. haemaphysaloides; and altitude and cattle breed for H. bispinosa and H. spinigera. MaxEnt models showed land cover to be an important predictor for the occurrence of all tick species examined. These findings provide information that can be used to initiate and plan enhanced tick surveillance and subsequent prevention and control programs for ticks and tick-borne diseases in cattle in Bhutan.

A global assessment of Echinococcus multilocularis infections in domestic dogs: proposing a framework to overcome past methodological heterogeneity

Echinococcus multilocularis, the aetiological agent of human Alveolar Echinococcosis, is transmitted between small mammals and wild or domestic canids. Dogs infected with E. multilocularis as dead-end hosts. Whereas E. multilocularis infections in wild hosts and humans have been well-studied in recent decades, infections in domestic dogs are sparsely reported. This literature review and meta-analysis highlighted gaps in the available data and provided a re-assessment of the global distribution of domestic dog E. multilocularis infections. We found 46 published articles documenting the prevalence of E. multilocularis in domestic dogs from 21 countries across Europe, Asia and North America. Apparent prevalence estimates ranged from 0.00% (0.00-0.33%) in Germany to 55.50% (26.67-81.12%) in China. Most studies were conducted in areas of high human Alveolar Echinococcosis. By accounting for reassessed diagnostic sensitivity and specificity, we estimated true prevalence in a subset of studies, which varied between 0.00% (0.00-12.42%) and 41.09% (21.12-65.81%), as these true prevalence estimates were seldom reported in the articles themselves. Articles also showed a heavy emphasis on rural dogs, dismissing urban ones, which is concerning due to the role urbanisation plays in the transmission of zoonotic diseases, especially those utilising pets as definitive hosts. Lastly, population studies on canine Alveolar Echinococcosis were absent, highlighting the relative focus on human rather than animal health. We thus developed a framework for investigating domestic dog E. multilocularis infections and performing risk assessment of dog-associated transmission to fill the gaps found in the literature.

Characterization of water treatment-resistant and multidrug-resistant urinary pathogenic Escherichia coli in treated wastewater

A growing body of evidence has demonstrated that extraintestinal pathogenic E. coli (ExPEC), such as the urinary pathogenic E. coli (UPEC), are common constituents of treated wastewater, and therefore represent a potential public health risk. However, no single virulence gene, or set of virulence genes, can be used to conclusively identify this genetically diverse pathotype. As such we sought to identify and characterize the public health relevance of potential UPEC found in treated sewage/wastewater using a comparative genomics approach. Presumptive wastewater UPEC (W-UPEC) were initially identified by virulence gene screening against 5 virulence genes, and for which isolates containing ≥3 virulence genes were whole genome sequenced (n = 24). Single nucleotide polymorphic (SNP) spanning tree analysis demonstrated that many of these wastewater UPEC (WUPEC) were virtually identical at the core genome (0.4 Mbp) when compared to clinical UPEC (C-UPEC) sequences obtained from NCBI, varying by as little as 1 SNP. Remarkably, at the whole genome level, W-UPEC isolates displayed >96% whole genome similarity to C-UPEC counterparts in NCBI, with one strain demonstrating 99.5% genome similarity to a particular C-UPEC strain. The W-UPEC populations were represented by sequence types (ST) known to be clinically important, including ST131, ST95, ST127 and ST640. Many of the W-UPEC carried the exact same complement of virulence genes as their most closely related C-UPEC strains. For example, O25b-ST131 W-UPEC strains possessed the same 80 virulence genes as their most closely related C-UPEC counterparts. Concerningly, W-UPEC strains also carried a plethora of antibiotic resistance genes, and O25b-ST131strains were designated as extended spectrum beta-lactamase (ESBL) producing E. coli by both genome profiling and phenotypic resistance testing. W-UPEC ST131 strains were found in the effluents of a single treatment plant at different times, as well as different wastewater treatment plants, suggesting a differentially ability to survive wastewater treatment. Indeed, in sewage samples treated with chlorine doses sufficient for inducing a ∼99.99% reduction in total E. coli levels, UPEC represented a significant proportion of the chlorine-resistant population. By contrast, no Shiga toxin-producing E. coli were observed in these chlorinated sewage libraries. Our results suggest that clinically-relevant UPEC exist in treated wastewater effluents and that they appear to be specifically adapted to survive wastewater treatment processes.

Exploring Well Water Testing Behaviour Through the Health Belief Model

Health problems can arise from consuming contaminated well water. Well water testing can help prevent negative health outcomes associated with consuming contaminated water. The aim of this study was to understand the factors influencing well owner decisions to conduct water testing through the theoretical lens of the Health Belief Model. We conducted semi-structured interviews with 20 well owners and used framework analysis to sort and analyse the data. The results demonstrated that well owners' perceived susceptibility to well water contamination was low, while the perceived severity of contamination, benefits of testing, and self-efficacy towards testing were high. Cues to action to promote testing focused on increasing well owner education and awareness through well stewardship programmes and reminders to test. Participants faced some barriers to water testing. Increasing education and awareness about well water contamination and water testing, while reducing logistical barriers to testing, may improve compliance with water testing.

Evaluating the risks associated with Shiga-toxin-producing Escherichia coli (STEC) in private well waters in Canada

Shiga-toxin-producing Escherichia coli (STEC) represent a major concern for waterborne disease outbreaks associated with consumption of contaminated groundwater. Over 4 million people rely on private groundwater systems as their primary drinking water source in Canada; many of these systems do not meet current standards for water quality. This manuscript provides a scoping overview of studies examining STEC prevalence and occurrence in groundwater, and it includes a synopsis of the environmental variables affecting survival, transport, persistence, and overall occurrence of these important pathogenic microbes in private groundwater wells used for drinking purposes.

A Transdisciplinary Approach to Brucella in Muskoxen of the Western Canadian Arctic 1989-2016

Brucella serostatus was evaluated in 3189 muskoxen sampled between 1989 and 2016 from various locations of the Canadian Arctic archipelago and mainland, near the communities of Sachs Harbour and Ulukhaktok, Northwest Territories, and Cambridge Bay and Kugluktuk, Nunavut. Brucella antibodies were found only in muskoxen sampled around Cambridge Bay, both on southern Victoria Island and on the adjacent mainland (Kent Peninsula). Consistent with participatory epidemiology data documented from local harvesters describing increased Brucella-like syndromes (swollen joints and lameness) and a decreased proportion of juveniles, the apparent Brucella seroprevalence in the sampled muskoxen of the Cambridge Bay area increased from 0.9% (95% CI 0.3-2.1) in the period of 1989-2001 to 5.6% (95% CI 3.3-8.9) in 2010-2016. The zoonotic bacteria Brucella suis biovar 4 was also cultured from tissues of muskoxen sampled on Victoria Island near Ulukhaktok in 1996 (n = 1) and Cambridge Bay in 1998, 2014, and 2016 (n = 3). Overall, our data demonstrate that B. suis biovar 4 is found in muskoxen that are harvested for food and by guided hunts on Victoria Island and Kent Peninsula, adding an important public health dimension to this study. Robust participatory epidemiology data on muskox health and diseases greatly enhanced the interpretation of our Cambridge Bay data and, combined with the serological and microbiological data, provide compelling evidence that the prevalence of B. suis biovar 4 has increased in this area since the late 1990s. This study enhances the available knowledge on Brucella exposure and infection in muskoxen and provides an example of how scientific knowledge and local knowledge can work together to better understand disease status in wildlife.

Evidence for the evolution, clonal expansion and global dissemination of water treatment-resistant naturalized strains of Escherichia coli in wastewater

We previously demonstrated the existence of naturalized strains of E. coli in wastewater and herein perform an in-depth comparative whole genome analysis of these strains (n = 17). Fourteen of the Canadian E. coli strains, isolated from geographically separated wastewater treatment plants, were virtually identical at the core genome and were ≥96% similar at the whole genome level, suggesting clonal-relatedness among these isolates. Remarkably, these strains were shown to be extremely similar to the genome of an E. coli isolated from wastewater in Switzerland, suggesting a global distribution of these strains. The genomes of three other Canadian wastewater strains were more diverse but very similar to the genomes of E. coli isolates collected from U.S. wastewater samples. Based on maximum likelihood phylogenetic analysis, wastewater strains from Canada, the U.S. and Switzerland formed a clade separate from other known enteric phylogroups (i.e., A, B1, B2, D, E) and the cryptic clades. All Canadian, Swiss and U.S. wastewater strains possessed a common SNP biomarker pattern across their genomes, and a sub-population (i.e., 14 Canadian and 1 Swiss strain) also possessed a previously identified wastewater-specific marker known as uspC-IS30-flhDC element. Biochemical heat mapping of 518 categories of genes recapitulated phylogeny, with wastewater strains phenotypically clustering separately from enteric and cryptic clades. Wastewater strains were enriched for stress-response genes (i.e., nutrient acquisition/deprivation, DNA repair, oxidative stress, and UV resistance) - elements reflective of their environmental survival challenges. Wastewater strains were shown to carry a plethora of known antibiotic resistance (AR) genes, the patterns of which were remarkably similar among all Canadian, U.S. and Swiss wastewater strains. Virulence gene composition was also similar among all the wastewater strains, with an abundant representation of virulence genes commonly associated with urinary pathogenic E. coli (UPEC) as well as enterohemorrhagic (EHEC) E. coli. The remarkable degree of similarity between all wastewater strains from Canada, Switzerland and the U.S. suggests the evolution and global-dissemination of water treatment-resistant clone of E. coli. These finding, along with others, raise some important concerns about the potential for emergence of E. coli pathotypes resistant to water-treatment.

Exposure to antimicrobial-resistant Escherichia coli through the consumption of ground beef in Western Canada

Emergence and dissemination of antimicrobial resistance (AMR) in food-borne bacteria is a public health issue. Retail meat is considered an important carrier for antimicrobial-resistant Escherichia coli. Currently, resistance of E. coli strains to third generation cephalosporins are of particular concern, with significant potential animal and public health consequences. Resistance to tetracyclines is also a concern, due to high prevalence of this resistance and important co-resistance patterns. However, the actual likelihood of exposure to antimicrobial-resistant bacteria via the consumption of retail meats, beyond the simple frequencies of resistance found in samples of meat at the grocery store, in Canada remains to be investigated. This study was conducted to estimate the potential human exposure to ceftriaxone- and tetracycline-resistant E.coli (CREC and TREC; the hazards of interest) through the consumption of ground beef in Western Canada. Our exposure assessment simulation model included five modules: 1) estimation of prevalence and concentration of the hazards of interest in retail ground beef samples collected by the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS), 2011-2014; 2) potential growth of the hazards during transportation from retail to home; 3) potential growth or reduction of the hazards during home storage; 4) thermal inactivation of the hazards due to cooking; and 5) consumption. The outputs of the model were presented as the probability of consumers' exposure to various threshold levels of the hazards [10 to 10⁶ colony forming units (CFU)] in one serving of cooked ground beef. Overall, the probabilities of exposure to high threshold levels of the hazards (>4 log₁₀ CFU/serving) were estimated to be lower than 0.12% in the study population (2011-2014). The mean probabilities of exposure to at least 1 log₁₀ CFU CREC and TREC in a single meal containing cooked ground beef were 0.067% (SD: 0.001%) and 1.20% (SD: 0.02%), respectively. This probability substantially decreased as the threshold level of exposure increased to ≥6 log₁₀ CFU. The probability of exposure to TREC was consistently greater than that for CREC. Cooking led to a prominent drop in the mean concentration of the hazards (4.7 log₁₀ CFU/g). The findings from this research could inform the policy-making process and provide suggestions for adjustments in future retail surveillance plans. In addition, important knowledge gaps in this area have been highlighted.

Total coliform and Escherichia coli contamination in rural well water: analysis for passive surveillance

With increasing stress on our water resources and recent waterborne disease outbreaks, understanding the epidemiology of waterborne pathogens is crucial to build surveillance systems. The purpose of this study was to explore techniques for describing microbial water quality in rural drinking water wells, based on spatiotemporal analysis, time series analysis and relative risk mapping. Tests results for Escherichia coli and coliforms from private and small public well water samples, collected between 2004 and 2012 in Alberta, Canada, were used for the analysis. Overall, 14.6 and 1.5% of the wells were total coliform and E. coli-positive, respectively. Private well samples were more often total coliform or E. coli-positive compared with untreated public well samples. Using relative risk mapping we were able to identify areas of higher risk for bacterial contamination of groundwater in the province not previously identified. Incorporation of time series analysis demonstrated peak contamination occurring for E. coli in July and a later peak for total coliforms in September, suggesting a temporal dissociation between these indicators in terms of groundwater quality, and highlighting the potential need to increase monitoring during certain periods of the year.

Clostridium difficile infection worsens the prognosis of ulcerative colitis

BACKGROUND

The impact of Clostridium difficile infections among ulcerative colitis (UC) patients is well characterized. However, there is little knowledge regarding the association between C difficile infections and postoperative complications among UC patients.

OBJECTIVE

To determine whether C difficile infection is associated with undergoing an emergent colectomy and experiencing postoperative complications.

METHODS

The present population-based case-control study identified UC patients admitted to Calgary Health Zone hospitals for a flare between 2000 and 2009. C difficile toxin tests ordered in hospital or 90 days before hospital admission were provided by Calgary Laboratory Services (Calgary, Alberta). Hospital records were reviewed to confirm diagnoses and to extract clinical data. Multivariate logistic regression analyses were performed among individuals tested for C difficile to examine the association between C difficile infection and emergent colectomy and diagnosis of any postoperative complications and, secondarily, an infectious postoperative complication. Estimates were presented as adjusted ORs with 95% CIs.

RESULTS

C difficile was tested in 278 (58%) UC patients and 6.1% were positive. C difficile infection was associated with an increased risk for emergent colectomy (adjusted OR 3.39 [95% CI 1.02 to 11.23]). Additionally, a preoperative diagnosis of C difficile was significantly associated with the development of postoperative infectious complications (OR 4.76 [95% CI 1.10 to 20.63]).

CONCLUSION

C difficile diagnosis worsened the prognosis of UC by increasing the risk of colectomy and postoperative infectious complications following colectomy. Future studies are needed to explore whether early detection and aggressive management of C difficile infection will improve UC outcomes.

Invasion, establishment, and range expansion of two parasitic nematodes in the Canadian Arctic

Climate warming is occurring at an unprecedented rate in the Arctic and is having profound effects on host-parasite interactions, including range expansion. Recently, two species of protostrongylid nematodes have emerged for the first time in muskoxen and caribou on Victoria Island in the western Canadian Arctic Archipelago. Umingmakstrongylus pallikuukensis, the muskox lungworm, was detected for the first time in 2008 in muskoxen at a community hunt on the southwest corner of the island and by 2012, it was found several hundred kilometers east in commercially harvested muskoxen near the town of Ikaluktutiak. In 2010, Varestrongylus sp., a recently discovered lungworm of caribou and muskoxen was found in muskoxen near Ikaluktutiak and has been found annually in this area since then. Whereas invasion of the island by U. pallikuukensis appears to have been mediated by stochastic movement of muskoxen from the mainland to the southwest corner of the island, Varestrongylus has likely been introduced at several times and locations by the seasonal migration of caribou between the island and the mainland. A newly permissive climate, now suitable for completion of the parasite life cycles in a single summer, likely facilitated the initial establishment and now drives range expansion for both parasites.

Methodological comparisons for antimicrobial resistance surveillance in feedlot cattle

BACKGROUND

The purpose of this study was to objectively compare methodological approaches that might be utilized in designing an antimicrobial resistance (AMR) surveillance program in beef feedlot cattle. Specifically, four separate comparisons were made to investigate their potential impact on estimates for prevalence of AMR. These included investigating potential differences between 2 different susceptibility testing methods (broth microdilution and disc diffusion), between 2 different target bacteria (non-type-specific E. coli [NTSEC] and Mannheimia haemolytica), between 2 strategies for sampling feces (individual samples collected per rectum and pooled samples collected from the pen floor), and between 2 strategies for determining which cattle to sample (cattle that were culture-positive for Mannheimia haemolytica and those that were culture-negative).

RESULTS

Comparing two susceptibility testing methods demonstrated differences in the likelihood of detecting resistance between automated disk diffusion (BioMIC®) and broth microdilution (Sensititre®) for both E. coli and M. haemolytica. Differences were also detected when comparing resistance between two bacterial organisms within the same cattle; there was a higher likelihood of detecting resistance in E. coli than in M. haemolytica. Differences in resistance prevalence were not detected when using individual animal or composite pen sampling strategies. No differences in resistance prevalences were detected in E. coli recovered from cattle that were culture-positive for M. haemolytica compared to those that were culture-negative, suggesting that sampling strategies which targeted recovery of E. coli from M. haemolytica-positive cattle would not provide biased results.

CONCLUSIONS

We found that for general purposes, the susceptibility test selected for AMR surveillance must be carefully chosen considering the purpose of the surveillance since the ability to detect resistance appears to vary between these tests depending upon the population where they are applied. Continued surveillance of AMR in M. haemolytica recovered by nasopharyngeal swab is recommended if monitoring an animal health pathogen is an objective of the surveillance program as results of surveillance using fecal E. coli cannot be extrapolated to this important respiratory pathogen. If surveillance of E. coli was pursued in the same population, study populations could target animals that were culture-positive for M. haemolytica without biasing estimates for AMR in E. coli. Composite pen-floor sampling or sampling of individuals per-rectum could possibly be used interchangeably for monitoring resistance in E. coli.

Cortisol and corticosterone independence in cortisol-dominant wildlife

Species have traditionally been defined as cortisol-dominant or corticosterone-dominant, depending on the glucocorticoid that is reported. To assess the degree of covariance versus independence between cortisol and corticosterone, 245 serum samples belonging to 219 individuals from 18 cortisol-dominant, non-domesticated species (6 mammalian orders) were compared by mass spectrometry. In these samples, which were elevated above baseline, concentration ranges were overlapping for cortisol and corticosterone although cortisol was dominant in every sample except one of 17 bighorn sheep with a corticosterone-biased cortisol-to-corticosterone ratio of 0.17. As expected, cortisol and corticosterone were strongly associated among species (r(2)=0.8; species with high absolute cortisol tend to have high absolute corticosterone concentrations), with wide variation in the species-average cortisol-to-corticosterone ratio (range 7.5-49) and an even wider ratio range across individuals (0.2-341). However, only 9 out of 13 species with >7 individuals showed a positive association between cortisol and corticosterone among individuals, and repeated measures of the cortisol-to-corticosterone ratio within individuals were weakly associated (CV range 3-136%). We conclude that corticosterone, although at lower concentrations, has the potential to signal independently of cortisol, and should be included in integrated endocrine models of stress responses.

Characterization of antimicrobial resistance and virulence genes in Enterococcus spp. isolated from retail meats in Alberta, Canada

The objective of this study was to characterize antimicrobial resistance (AMR) and virulence genotypes of Enterococcus spp. particularly Enterococcus faecalis isolated from retail meats purchased (2007-2008) in Alberta, Canada. Unconditional statistical associations between AMR pheno- and genotypes and virulence genotypes were determined. A total of 532 enterococci comprising one isolate from each positive sample were analyzed for antimicrobial susceptibility. A customized enterococcal microarray was used for species identification and the detection of AMR and virulence genes. E. faecalis was found in >94% of poultry samples and in about 73% of beef and 86% of pork samples. Enterococcus faecium was not found in turkey meat and its prevalence was 2% in beef and pork and 4% in chicken samples. None of the enterococci isolates were resistant to the clinically important drugs ciprofloxacin, daptomycin, linezolid and vancomycin. Multiresistance (≥3 antimicrobials) was more common in E. faecalis (91%) isolated from chicken and turkey (91%) than those isolated from beef (14%) or pork (45%). Resistance to aminoglycosides was also noted at varying degrees. The most common resistance genes found in E. faecalis were aminoglycosides (aac, aphA3, aadE, sat4, aadA), macrolides (ermB, ermA), tetracyclines (tetM, tetL, tetO), streptogramin (vatE), bacitracin (bcrR) and lincosamide (linB). Virulence genes expressing aggregation substances (agg) and cytolysin (cylA, cylB, cylL, cylM) were found more frequently in poultry E. faecalis and were unconditionally associated with tetM, linB and bcrR resistance genes. Other virulence genes coding for adhesion (ace, efaAfs), gelatinase (gelE) were also found in the majority of E. faecalis. Significant statistical associations were found between resistance and virulence genotypes, suggesting their possible physical link on a common genetic element. This study underscores the importance of E. faecalis as a reservoir of resistance and virulence genes and their potential transfer to humans through consumption of contaminated undercooked meat.

Effect of neuroticism, response style and information processing on depression severity in a clinically depressed sample

BACKGROUND

It is postulated that individuals who score high on neuroticism would ruminate when faced with stress. A ruminative response style to depression is associated with faulty attribution and higher dysfunctional beliefs, which in turn is associated with a higher level of depression and hopelessness. Distraction is associated with less severe depression. Evidence supporting these hypotheses mainly comes from a non-clinical population. Hence it is not clear if these theories apply to clinical depression.

METHOD

One hundred and nine out-patients suffering from unipolar major depressive disorder were recruited to test these theories, using model-fitting analysis technique.

RESULTS

Certain rumination responses to depression were associated with higher levels of depression and hopelessness, faulty attribution and dysfunctional attitudes when gender and the level of depression were controlled. Principal component analysis of the Rumination Scale yielded four factors: 'symptom-based rumination', 'isolation/introspection', 'self-blame' and 'analyse to understand'. Unlike the other factors, 'analyse to understand' did not correlate with the level of depression. Model fitting analysis, though not reflecting entirely the true model, captures most of the hypothesized relationships between important variables. Neuroticism was associated with stress. Rumination was associated with an increased level of dysfunctional beliefs and faulty attribution, which in turn was associated with increased severity of depression. Distraction, in contrast, was associated with lower levels of negative mood.

CONCLUSION

The results of our study support the importance of teaching depressed patients to manage their depressive symptoms by avoiding rumination about their symptoms and engaging in distracting and pleasurable activities.

Childhood Experience of Care and Abuse Questionnaire (CECA.Q). Validation of a screening instrument for childhood adversity in clinical populations

BACKGROUND

Interview measures for investigating adverse childhood experiences, such as the Childhood Experience of Care and Abuse (CECA) instrument, are comprehensive and can be lengthy and time-consuming. A questionnaire version of the CECA (CECA.Q) has been developed which could allow for screening of individuals in research settings. This would enable researchers to identify individuals with adverse early experiences who might benefit from an in-depth interview. This paper aims to validate the CECA.Q against the CECA interview in a clinical population.

METHODS

One hundred and eight patients attending an affective disorders service were assessed using both the CECA interview and questionnaire measures. A follow-up sample was recruited 3 years later and sent the questionnaire. The questionnaire was also compared with the established Parental Bonding Instrument (PBI).

RESULTS

Agreement between ratings on the interview and questionnaire were high. Scales measuring antipathy and neglect also correlated highly with the PBI. The follow-up sample revealed the questionnaire to have a high degree of reliability over a long period of time.

CONCLUSIONS

The CECA.Q appears to be a reliable and valid measure which can be used in research on clinical populations to screen for individuals who have experienced severe adversity in childhood.

Adrenocortical, autonomic, and inflammatory causes of the metabolic syndrome: nested case-control study

BACKGROUND

The causes of metabolic syndrome (MS), which may be a precursor of coronary disease, are uncertain. We hypothesize that disturbances in neuroendocrine and cardiac autonomic activity (CAA) contribute to development of MS. We examine reversibility and the power of psychosocial and behavioral factors to explain the neuroendocrine adaptations that accompany MS.

METHODS AND RESULTS

This was a double-blind case-control study of working men aged 45 to 63 years drawn from the Whitehall II cohort. MS cases (n=30) were compared with healthy controls (n=153). Cortisol secretion, sensitivity, and 24-hour cortisol metabolite and catecholamine output were measured over 2 days. CAA was obtained from power spectral analysis of heart rate variability (HRV) recordings. Twenty-four-hour cortisol metabolite and normetanephrine (3-methoxynorepinephrine) outputs were higher among cases than controls (+ 0.49, +0.45 SD, respectively). HRV and total power were lower among cases (both -0.72 SD). Serum interleukin-6, plasma C-reactive protein, and viscosity were higher among cases (+0.89, +0.51, and +0.72 SD). Lower HRV was associated with higher normetanephrine output (r=-0.19; P=0.03). Among former cases (MS 5 years previously, n=23), cortisol output, heart rate, and interleukin-6 were at the level of controls. Psychosocial factors accounted for 37% of the link between MS and normetanephrine output, and 7% to 19% for CAA. Health-related behaviors accounted for 5% to 18% of neuroendocrine differences.

CONCLUSIONS

Neuroendocrine stress axes are activated in MS. There is relative cardiac sympathetic predominance. The neuroendocrine changes may be reversible. This case-control study provides the first evidence that chronic stress may be a cause of MS. Confirmatory prospective studies are required.

Managing lead exposure and toxicity in cow-calf herds to minimize the potential for food residues

Lead poisoning is commonly diagnosed in cattle. In this study, 3 groups of cattle from different herds accidentally exposed to discarded lead batteries on pasture were intensively studied to determine the extent and severity of exposure. The losses from acute death due to lead toxicity were substantial in all the 3 study groups at 12%, 17%, and 4%. Blood samples were taken from all cattle around the time of the first diagnosis and then later in 2 of the 3 herds to monitor the change in lead concentrations over time. Asymptomatic lead toxicosis was observed in these herds. In these 3 groups, between 4% and 12% of asymptomatic cattle had blood lead concentrations consistent with acute lead poisoning (> 0.35 ppm), and between 7% and 40% of these asymptomatic animals were in the high-normal range (0.1-0.35 ppm). Because of the consistently high number of asymptomatic cattle with elevated lead levels, all cattle potentially exposed to a lead source should be tested before sale or slaughter to minimize the entry of lead into the food chain. The blood lead concentrations, which were monitored for months after the initial diagnosis, decreased slowly after the cattle were removed from the lead source. The prolonged retention of lead may be due to continued release and absorption of lead from metal particles in the reticulum or rumen. The mean reduction in the lead level was 0.046 ppm (95% CI, 0.017-0.075 ppm) every 30 days for these 2 herds. Using a single-component exponential model, the half-life of lead in the animals retested from Herds 1 and 2 was highly variable. The median half-life was 63 days (interquartile range, 34-107 days). One out of 8 pregnant heifers with high blood levels had a stillborn calf. There were no abortions or calf mortalities in this group. Blood samples were'collected from the calves around the time of birth. The concentrations of lead in the blood of the calves exposed in utero were low (0.010-0.095 ppm).

Salivary cortisol during opiate dependence and withdrawal

Seventeen inpatients (14 men, three women) with opiate dependence and polysubstance misuse participated in a longitudinal study of salivary cortisol secretion during and after lofexidine detoxification treatment. Both opiate withdrawal symptoms and salivary cortisol were measured every morning for up to 25 days. Results were compared with a control group of 10 normal volunteers. There was an 80% reduction in withdrawal symptom severity between the first 12 days and the subsequent 12 days of treatment. Salivary cortisol fell from a mean of 22.3 nm/l over days 1-12 to 18.5 nm/l during days 13-25, a reduction of 17%. Salivary cortisol concentration correlated significantly with withdrawal symptom severity. Salivary cortisol levels remained significantly higher than controls for the duration of the study. The study supports a role for hypothalamo-pituitary-adrenal (HPA) activation in opiate withdrawal. The contribution of persistant dysregulation of the HPA, found in this study, to the vulnerability for relapse after abstinence has been achieved, is discussed.

Acquired mind-blindness following frontal lobe surgery? A single case study of impaired 'theory of mind' in a patient treated with stereotactic anterior capsulotomy

Social insight, specifically the ability to represent thoughts and feelings ('theory of mind'), may have a circumscribed and dedicated neurological substrate. Evidence of deficits in 'theory of mind' following acquired lesions would support this idea. Previous studies of lesions resulting from stroke or head injury have been hampered by lack of detailed lesion information and pre-lesion documentation. We report the case of a 76-year-old man who, following a standard surgical procedure to treat bipolar affective disorder, showed evidence of impaired 'theory of mind'. This case, which is the first of its type, may contribute to the search for the brain basis of social insight.

Salivary cortisol profiles in chronic fatigue syndrome

Salivary cortisol profiles (hourly sampling over a 16-hour period) of 10 patients with chronic fatigue syndrome (CFS) but without concurrent depressive disorder were compared with those of 10 healthy volunteers matched for age, sex and menstrual cycle. The mean saliva cortisol concentration over the 16-hour period was slightly but significantly greater in the patients than the controls (p < 0.05). These findings are at variance with earlier reports that CFS is a hypocortisolaemic state and suggest that in CFS the symptom of fatigue is not caused by hypocortisolaemia.

Increased salivary cortisol reliably induced by a protein-rich midday meal

OBJECTIVE

This study was conducted to determine whether an increase in salivary free cortisol would be reliably elicited by a midday meal, thus providing a convenient physiological challenge to the hypothalamic-pituitary-adrenal (HPA) axis, and whether this cortisol release depended on the protein content of the meal.

METHOD

In healthy men, free cortisol was measured in saliva samples taken before and after two identical protein-rich midday meals (39% energy as protein) and compared with a day on which no meal was eaten. Next, in healthy women in a nonclinical setting, salivary cortisol was measured before and after a protein-rich meal (32% energy as protein) on one day and a low-protein meal (5% energy as protein) on another day. Measures of mood, appetite, and psychological well-being were also taken.

RESULTS

An acute meal-dependent increase in salivary cortisol occurred, which was reliable over 2 test days. This increase in cortisol depended on the proportion of protein in the meal, increasing after the high-protein but not the low-protein meal. The extent of this increase in cortisol correlated significantly with poor psychological well-being in women. Some postmeal improvement of mood (positive affect) was associated with the high- but not the low-protein meal.

CONCLUSIONS

The cortisol response to meals may have implications for the effects of meal composition on mood, cognitive function, and food choice. The measurement of free cortisol in saliva provides a psychologically stress-free and reliable technique to assess the cortisol response to a standard protein-rich meal, ie, a physiological challenge to the HPA axis in men and women that could be investigated in naturalistic settings outside the laboratory.

Neurodevelopmental antecedents of early-onset bipolar affective disorder

BACKGROUND

Developmental impairments have been identified as a risk factor for early-onset schizophrenia. Affective symptoms are more common in children and adolescents with disordered neurodevelopmental than in healthy controls.

AIMS

To test the hypothesis that severe early-onset mood disorders are associated with developmental antecedents.

METHOD

We retrospectively identified 38 adolescent cases (15 female, 23 male; mean age 14.4 years, range 11-18) who met ICD-10 Research Diagnostic Criteria for a manic episode, bipolar affective disorder or psychotic depression, and 41 controls (25 female, 16 male, mean age 14.2 years, range 11-18) with depression but without psychotic features.

RESULTS

Cases were significantly more likely to have experienced delayed language, social or motor development (OR 5.5, 95% CI = 1.4-21.6, P = 0.01), in particular those who develop psychotic symptoms (OR 7.2, 95% CI = 1.8-28.6, P = 0.003).

CONCLUSIONS

Compared to early-onset unipolar depression, neurodevelopmental antecedents are over-represented in early-onset bipolar disorder. The validity of this finding was supported by contemporaneous IQ scores that are not subject to the same potential biases as case-note ratings.

How does marriage protect women with histories of affective disorder from post-partum relapse?

Interviews were carried out at 36 weeks antenatal with 63 married couples, in 36 of which the woman had a history of affective disorder and in 27 the woman had no previous psychiatric history. The men's attitudes to their wives were assessed using expressed emotion methodology. Also assessed were psychiatric history, neuroticism, satisfaction with the marital relationship and attitudes to sex, pregnancy and parenthood in both the woman and her partner. Women with psychiatric histories who did not relapse in the six months following delivery had partners who were more positive about them than partners of high-risk women who remained well and control women. This effect is explored further by examining which characteristics of the man and which of the woman contributed to his critical and positive comment score. Criticism of his wife was associated with each partner reporting less marital satisfaction and also with the man's psychiatric history. No characteristic of the woman contributed to her partner's criticism. In contrast, the men's positive comments about their wives were associated with the woman's satisfaction with key aspects of her femaleness. Positive husbands had wives were pleased to be pregnant, happy with their pregnant bodies and enjoying the sexual aspect of the marital relationship. In women with psychiatric histories the time which had elapsed since her last psychiatric admission also influenced his positive comments.

The neuroendocrinology of depression and chronic stress

This chapter will review basic and clinical studies of the social, genetic and developmental influences upon the reactivity of the hypothalamic pituitary adrenal (HPA) axis and the relationship of these to depression. Significant advances have taken place in each of these areas and it is now possible to interlink many of these areas of work. In order to do so, this chapter will be organised into five sections. The first section will show how the neuroendocrinology of chronic stress is characterised by an up-regulation of the central drive to the HPA axis in conjunction with down-regulation of its negative feedback control. The second will show that very similar processes occur in depressive illness. The third section will describe social, developmental and genetic influences on the HPA axis both in experimental animals and in man. The fourth will show how activation of the HPA axis can influence the development of animal models of depression as well as the onset and perpetuation of clinical depression. The final section will draw together an overall hypothesis and indicate the potential for new treatments for depression that arise from this work.

Dependency, matching adversities, length of survival and relapse in major depression

This paper reports the 1-year follow-up of a sample of depressed patients. Social cognitive variables obtained during the index episode, including ideal emotional support, roles and goals investment in various domains and dysfunctional attitudes were used to predict subjects' likelihood for subsequent relapse. More subjects who experienced severe life events in the year were found to have relapsed. However, the predictive value of life events was improved if adversity was in the most invested domain according to the roles and goals questionnaire that subjects filled in during their index episode (matching adversity). Subjects who experienced matching adversity had a 3-fold chance of relapse compared with subjects with nonmatching adversity. The majority of the matching events were in the interpersonal domain. Levels of dysfunctional attitudes alone did not predict relapse. However, matching adversity and the dependency subscale of the dysfunctional attitude scale contributed significantly both to whether or not subjects relapsed and to the number of weeks subjects survived before they relapsed. The higher the level of dependency dysfunctional attitudes, the sooner subjects relapsed. The findings of the follow-up study supported the importance of psychological and social factors in determining relapse.

Continuous administration of human corticotropin-releasing hormone in the absence of glucocorticoid feedback in man

Continuous 24-hour infusions of a maximally stimulating dose (1 microgram/kg/h) of corticotropin-releasing hormone (CRH) have been shown to cause elevations of plasma cortisol and ACTH, but the pattern of results were confounded by serum cortisol causing feedback changes. We have looked at ACTH responses to saline or CRH infusions over 24 h in 6 normal subjects who, in addition, received either placebo or metyrapone, an 11 beta-hydroxylase inhibitor which blocks the formation of cortisol and thus abolishes glucocorticoid feedback. Cortisol and ACTH levels were measured by radioimmunoassay. Before metyrapone, CRH infusion resulted in exaggerated ACTH peaks throughout the day, as compared with normal saline: there was no influence on the noctural rise in ACTH. Following metyrapone alone, absolute cortisol levels were lower but circadian rhythmicity was preserved. Circadian rhythm of ACTH was maintained, with a fall in the evening to 14.5 +/- 4 pg/ml (mean +/- SE) at midnight and an exaggerated rise overnight, reaching a peak level of 90 +/- 33 pg/ml at 07:00 h. Subjects receiving CRH with metyrapone showed a similar pattern of responses, but with further enhanced ACTH levels. The evening fall reached a nadir of 30 +/- 6 pg/ml at 01:00 h. With diminished glucocorticoid feedback the nocturnal rise in ACTH was augmented by CRH infusion, with a morning peak of 193 +/- 21 pg/ml at 07:00 h. Thus, continuous infusion of CRH in the absence of steroid feedback leads to a retention of the circadian rhythmicity in ACTH secretion, reset at a higher absolute level.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatic necrosis associated with halothane anesthesia in an alpaca

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The impact of social cognitive variables on the initial level of depression and recovery

Thirty-seven patients who fulfilled DSM-III-R criteria for Major Depressive Disorder were recruited for a double-blind controlled trial of Desipramine and placebo for 6 weeks. Data about social cognitive variables, including social adversities, investment in roles and goals, general social support and crisis support were collected. Crisis support had a moderating effect on the initial level of depression: the more crisis support the subjects had, the less depressed they were on recruitment. Initial level of depression, the experience of adversity and drugs all contributed significantly to recovery defined as Hamilton Rating for Depression less than 10 at week 6. When recovery was defined as Hamilton score halved or more than halved between week 2 and week 6, subjects' level of ideal emotional support, and whether they had experienced adversity in their most invested domains, contributed significantly to recovery, independent of any drug effects or the initial level of depression. The higher their level of ideal emotional support, the less was the chance of these subjects recovering. The findings of this study pointed to the importance of controlling for psycho-social variables in studies of response to treatment.

Neuroendocrine and psychosocial mechanisms in post-partum psychosis

(1) Results from a study investigating psychosocial and neuroendocrine influences on post-partum psychosis are presented. Subjects were 43 pregnant women with histories of affective disorder (bipolar or schizoaffective disorder, n = 26; major depressive disorder, n = 17), together with 45 pregnant women without any psychiatric history. (2) At 36 weeks antenatal assessments were carried out of the women's psychiatric histories, current psychiatric state and also the occurrence of life events in the preceding year. They were then monitored for 6 months after delivery during which time psychiatric state and any further life events were recorded. Illness was defined according to Research Diagnostic Criteria (RDC); 22 high risk women and 3 control women were categorised as RDC 'cases' during the post-partum follow-up period. Fifteen of the bipolar/schizoaffective women (8 of whom subsequently became ill within 3 months of delivery) and 15 controls (all of whom remained well) also participated in a neuroendocrine test at 4 days post-partum when their growth hormone response to a challenge dose of the dopamine agonist, apomorphine, was measured. (3) The results showed that women with histories of depression and control women who became ill after delivery were three times more likely to have had a life event in the year preceding onset of illness than women from these subgroups who remained well. In contrast, for women with histories of bipolar or schizoaffective disorder, life events appeared to be unimportant. Instead bipolar/schizoaffective women who became ill showed an enhanced growth hormone response to the apomorphine challenge test compared to those who remained well and controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Neuroendocrine mechanisms and the precipitation of depression by life events

It is now generally accepted that stressful life events and chronic difficulties can trigger the onset of depression in predisposed individuals. However, although much is known of the neurobiology of stress, few attempts have been made to provide a biological explanation for the mechanisms whereby life events might trigger depression. Enough is now known of the central control of hypothalamic pituitary adrenal (HPA) function and its response to stress to permit an examination of its role in the neurobiology of the triggering of depression by stress. This evidence is reviewed, and the proposal explored that stress triggers depression by a genomic action of corticosteroids.