Abstract: The oomycete Aphanomyces astaci causes crayfish plague, a disease threatening native European crayfish. It is carried and transmitted by American crayfish species, which are the original hosts of A. astaci . In recent years, environmental DNA (eDNA) methods have been successfully implemented to monitor the spread of both A. astaci and its hosts. However, still little is known about how population density and other environmental factors influence the detectability of this host-pathogen complex. In a mesocosm experiment, we tested the influence of crayfish density, temperature and food availability on the detectability of eDNA for A. astaci and its host, signal crayfish Pacifastacus leniusculus . We also compared eDNA results with crayfish population density measured by catch per unit effort (CPUE) from two lakes with varying crayfish density and A. astaci prevalence. The mesocosm experiment revealed that a limited set of controlled factors can substantially change the detectable amount of eDNA, even though the physical presence of the target organisms remains the same. In cold, clear water, eDNA quantities of both targets increased far more than in a linear fashion with increased crayfish density. However, the presence of food decreased the detectability of crayfish eDNA, presumably through increased microbial-induced eDNA degradation. For A. astaci , where eDNA typically represents living spores, food did not affect the detectability. However, high water temperature strongly reduced it. The increased complexity and variability of factors influencing eDNA concentration under natural conditions, compared to a controlled experimental environment, suggests that establishing a reliable relationship between eDNA quantities and crayfish density is difficult to achieve. This was also supported by field data, where we found minimal correspondence between eDNA quantity and CPUE data. A comparison between quantitative real-time PCR (qPCR) analysis and droplet-digital PCR (ddPCR) analysis revealed higher detection success of the targets in field samples when using qPCR. Overall, our results support eDNA as an effective tool for presence-absence monitoring, but it seems less suited for biomass quantification and population density estimates. Detection of A. astaci and P. leniusculus is not influenced uniformly by respective environmental factors. Consequently, we recommend a strategy of monitoring both targets, where the detection of one may point towards the presence of the other.

Abstract: 〈 p 〉 〈 strong 〉 List of Abstract Titles and authors: 〈 br / 〉 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 1. Psychosis: A matter of mental effort? 〈 /strong 〉 〈 /p 〉 〈 p 〉 M Borg, Y Y van der Zee, J H Hsieh, H Temmingh, D J Stein, F M Howells 〈 /p 〉 〈 p 〉 〈 strong 〉 2.In search of an affordable, effective post-discharge intervention: A randomised control trial assessing the influence of a telephone-based intervention on readmissions for patients with severe mental illness in a developing country 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 U A Botha, L Koen, M Mazinu, E Jordaan, D J H Niehaus 〈 /p 〉 〈 p 〉 〈 strong 〉 3. The effect of early abstinence from long-term methamphetamine use on brain metabolism using 1H-magnetic resonance spectro-scopy (1H-MRS) 〈 /strong 〉 〈 /p 〉 〈 p 〉 A Burger, S Brooks, D J Stein, F M Howells 〈 /p 〉 〈 p 〉 〈 strong 〉 4. The effect of 〈 em 〉 in utero exposure  〈 /em 〉 to methamphetamine on brain metabolism in childhood using 1H-magnetic resonance spectroscopy (1H-MRS) 〈 /strong 〉 〈 /p 〉 〈 p 〉 A Burger, A Roos, M Kwiatkowski, D J Stein, K A Donald, F M Howells 〈 /p 〉 〈 p 〉 〈 strong 〉 5. A prospective study of clinical, biological and functional aspects of outcome in first-episode psychosis: The EONKCS Study 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 B Chiliza, L Asmal, R Emsley 〈 /p 〉 〈 p 〉 〈 strong 〉 6. Stimulants as cognitive enhancers - perceptions v. evidence in a very real world 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 H M Clark 〈 /p 〉 〈 p 〉 〈 strong 〉 7. Pharmacogenomics in antipsychotic drugs 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 Ilse du Plessis 〈 /p 〉 〈 p 〉 〈 strong 〉 8. Serotonin in anxiety disorders and beyond 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 Ilse du Plessis 〈 /p 〉 〈 p 〉 〈 strong 〉 9. HIV infection results in ventral-striatal reward system hypo-activation during cue processing 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 S du Plessis, M Vink, J A Joska, E Koutsilieri, A Bagadia, D J Stein, R Emsley 〈 /p 〉 〈 p 〉 〈 strong 〉 10. Disease progression in schizophrenia: Is the illness or the treatment to blame? 〈 /strong 〉 〈 /p 〉 〈 p 〉 R Emsley, M J Sian 〈 /p 〉 〈 p 〉 〈 strong 〉 11. Serotonin transporter variants play a role in anxiety sensitivity in South African adolescents 〈 /strong 〉 〈 /p 〉 〈 p 〉  S M J Hemmings, L I Martin, L van der Merwe, R Benecke, K Domschke, S Seedat 〈 /p 〉 〈 p 〉 〈 strong 〉 12. Iron deficiency in two children diagnosed with multiple sclerosis: Report on whole exom sequencing 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 S Janse van Rensburg, R van Toorn, J F Schoeman, A Peeters, L R Fisher, K Moremi, M J Kotze 〈 /p 〉 〈 p 〉 〈 strong 〉 13. Benzodiazepines: Practical pharmacokinetics 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 P Joubert 〈 /p 〉 〈 p 〉 〈 strong 〉 14. What to consider when prescribing psychotropic medications 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 G Lippi 〈 /p 〉 〈 p 〉 〈 strong 〉 15. Current prescribing practices for obsessive-compulsive disorder in South Africa: Controversies and consensus 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 C Lochner, L Taljaard, D J Stein 〈 /p 〉 〈 p 〉 〈 strong 〉 16. Correlates of emotional and behavioural problems in children with preinatally acquired HIV in Cape Town, South Africa 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 K-A Louw, N Phillips, JIpser, J Hoare 〈 /p 〉 〈 p 〉 〈 strong 〉 17. The role of non-coding RNAs in fear extinction 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 S Malan-Muller, L Fairbairn, W M U Daniels, M J S Dashti, E J Oakleley, M Altorfer, J Harvey, S Seedat, J Gamieldien, S M J Hemmings 〈 /p 〉 〈 p 〉 〈 strong 〉 18. An analysis of the management og HIV-mental illness comorbidity at the psychiatric unit of the Dr George Mukhari Academic Hospital 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 M L Maodi, S T Rataemane, T Kyaw 〈 /p 〉 〈 p 〉 〈 strong 〉 19. The identification of novel genes in anxiety disorders: A gene X environment correlation and interaction study 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 N W McGregor, J Dimatelis, S M J Hemmings, C J Kinnear, D J Stein, V Russel, C Lochner 〈 /p 〉 〈 p 〉 〈 strong 〉 20. Collaborations between conventional medicine and traditional healers: Obstacles and possibilities 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 G Nortje, S Seedat, O Gureje 〈 /p 〉 〈 p 〉 〈 strong 〉 21. Thought disorder and form perception: Relationships with symptoms and cognitive function in first-episode schizophrenia 〈 /strong 〉 〈 /p 〉 〈 p 〉 M R Olivier, R Emsley 〈 /p 〉 〈 p 〉 〈 strong 〉 22. Investigating the functional significance of genome-wide variants associated with antipsychotic treatment response 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 E Ovenden, B Drogemoller, L van der Merwe, R Emsley, L Warnich 〈 /p 〉 〈 p 〉 〈 strong 〉 23. The moral and bioethical determinants of "futility" in psychiatry 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 W P Pienaar 〈 /p 〉 〈 p 〉 〈 strong 〉 24. Single voxel proton magnetic resonance spectroscopy (1H-MRS) and volumetry of the amylgdala in social anxiety disorder in the context of early developmental trauma 〈 /strong 〉 〈 /p 〉 〈 p 〉 D Rosenstein, A T Hess, J Zwart, F Ahmed-Leitao, E Meintjies, S Seedat 〈 /p 〉 〈 p 〉 〈 strong 〉 25. Schizoaffective disorder in an acute psychiatric unit: Profile of users and agreement with Operational Criteria (OPCRIT) 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 R R Singh, U Subramaney 〈 /p 〉 〈 p 〉 〈 strong 〉 26. The right to privacy and confidentiality: The ethics of expert diagnosis in the public media and the Oscar Pistorius trial 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 C Smith 〈 /p 〉 〈 p 〉 〈 strong 〉 27. A birth cohort study in South Africa: A psychiatric perspective 〈 /strong 〉 〈 /p 〉 〈 p 〉 D J Stein 〈 /p 〉 〈 p 〉 〈 strong 〉 28. 'Womb Raiders': Women referred for observation in terms of the Criminal Procedures Act (CPA) charged with fetal abduction and murder 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 U Subramaney 〈 /p 〉 〈 p 〉 〈 strong 〉 29. Psycho-pharmacology of sleep wake disorders: An update 〈 /strong 〉 〈 /p 〉 〈 p 〉 R Sykes 〈 /p 〉 〈 p 〉 〈 strong 〉 30. Refugee post-settlement in South Africa: Role of adjustment challenges and family in mental health outcomes 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 L Thela, A Tomita, V Maharaj, M Mhlongo, K Jonathan 〈 /p 〉 〈 p 〉 〈 strong 〉 31. Dstinguishing ADHD symptoms in psychotic disorders: A new insight in the adult ADHD questionnaire 〈 /strong 〉 〈 /p 〉 〈 p 〉 Y van der Zee, M Borg, J H Hsieh, H Temmingh, D J Stein, F M Howells 〈 /p 〉 〈 p 〉 〈 strong 〉 32. Oscar Pistorius ethical dilemmas in a trial by media: Does this include psychiatric evaluation by media? 〈 /strong 〉 〈 /p 〉 〈 p 〉 M Vorster 〈 /p 〉 〈 p 〉 〈 strong 〉 33. Genetic investigation of apetite aggression in South African former young offenders: The involvement of serotonin transporter gene 〈 /strong 〉 〈 /p 〉 〈 p 〉 K Xulu, J Somer, M Hinsberger, R Weierstall, T Elbert, S Seedat, S Hemmings 〈 /p 〉 〈 p 〉 〈 strong 〉 34. Effects of HIV and childhood trauma on brain morphemtry and neurocognitive function 〈 /strong 〉 〈 /p 〉 〈 p 〉 G Spies, F Ahmed-Leitao, C Fennema-Notestine, M Cherner, S Seedat 〈 /p 〉 〈 p 〉 〈 strong 〉 35. Measuring intentional behaviour normative data of a newly developed motor task battery 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 S Bakelaar, J Blampain, S Seedat, J van Hoof, Y Delevoye-Turrel 〈 /p 〉 〈 p 〉 〈 strong 〉 36. Resilience in social anxiety disorder and post-traumatic stress disorder in the context of childhood trauma 〈 /strong 〉 〈 /p 〉 〈 p 〉 M Bship, S Bakelaar, D Rosenstein, S Seedat 〈 /p 〉 〈 p 〉 〈 strong 〉 37. The ethical dilemma of seclusion practices in psychiatry 〈 /strong 〉 〈 /p 〉 〈 p 〉 G Chiba, U Subramaney 〈 /p 〉 〈 p 〉 〈 strong 〉 38. Physical activity and neurological soft signs in patients with schizophrenia 〈 /strong 〉 〈 /p 〉 〈 p 〉 O Esan, C Osunbote, I Oladele, S Fakunle, C Ehindero 〈 /p 〉 〈 p 〉 〈 strong 〉 39. A retrospective study of completed suicides in the Nelson Mandela Bay Metropolitan Area from 2008 to 2013 - preliminary results 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 C Grobler, J Strumpher, R Jacobs 〈 /p 〉 〈 p 〉 〈 strong 〉 40. Serotonin transporter variants play a role in anxiety sensitivity in South African adolescents 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 S M J Hemmings, L I Martin, L van der Merwe, R Benecke, K Domschke, S Seedat 〈 /p 〉 〈 p 〉 〈 strong 〉 41. Investigation of variants within antipsychotic candidate pharmacogenes associated with treatment outcome 〈 /strong 〉 〈 /p 〉 〈 p 〉 F Higgins, B Drogmoller, G Wright, L van der Merwe, N McGregor, B Chiliza, L Asmal, L Koen, D Niehaus, R Emsley, L Warnich 〈 /p 〉 〈 p 〉 〈 strong 〉 42. Effects of diet, smoking and alcohol consumption on disability (EDSS) in people diagnosed with multiple sclerosis 〈 /strong 〉 〈 /p 〉 〈 p 〉 S Janse van Rensburg, W Davis, D Geiger, F J Cronje, L Whati, M Kidd, M J Kotze 〈 /p 〉 〈 p 〉 〈 strong 〉 43. The clinical utility of neuroimaging in an acute adolescnet psychiatric inpatient population 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 Z Khan, A Lachman, J Harvey 〈 /p 〉 〈 p 〉 〈 strong 〉 44. Relationships between childhood trauma (CT) and premorbid adjustment (PA) in a highly traumatised sample of patients with first-episode schizophrenia (FES 〈 /strong 〉 ) 〈 /p 〉 〈 p 〉 S Kilian, J Burns, S Seedat, L Asmal, B Chiliza, S du Plessis, R Olivier, R Emsley 〈 /p 〉 〈 p 〉 〈 strong 〉 45. Functional and cognitive outcomes using an mTOR inhibitor in an adolescent with TSC 〈 /strong 〉 〈 /p 〉 〈 p 〉 A Lachman, C van der Merwe, P Boyes, P de Vries 〈 /p 〉 〈 p 〉 〈 strong 〉 46. Perceptions about adolescent body image and eating behaviour 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 K Laxton, A B R Janse van Rensburg 〈 /p 〉 〈 p 〉 〈 strong 〉 47. Clinical relevance of FTO rs9939609 as a determinant of cardio-metabolic risk in South African patients with major depressive disorder 〈 /strong 〉 〈 /p 〉 〈 p 〉 H K Luckhoff, M J Kotze 〈 /p 〉 〈 p 〉 〈 strong 〉 48. Childhood abuse and neglect as predictors of deficits in verbal auditory memory in non-clinical adolescents with low anxiety proneness 〈 /strong 〉 〈 /p 〉 〈 p 〉 L Martin, K Martin, S Seedat 〈 /p 〉 〈 p 〉 〈 strong 〉 49. The changes of pro-inflammatory cytokines in a prenatally stressed febrile seizure animal model and whether 〈 em 〉 Rhus chirindensis 〈 /em 〉 may attenuate these changes 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 A Mohamed, M V Mabandla, L Qulu 〈 /p 〉 〈 p 〉 〈 strong 〉 50. Influence of TMPRSS6 A736v and HFE C282y on serum iron parameters and age of onset in patients with multiple sclerosis 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 K E Moremi, M J Kotze, H K Luckhoff, L R Fisher, M Kidd, R van Toorn, S Janse van Rensburg 〈 /p 〉 〈 p 〉 〈 strong 〉 51. Polypharmacy in pregnant women with serious mental illness 〈 /strong 〉 〈 /p 〉 〈 p 〉 E Thomas, E du Toit, L Koen, D Niehaus 〈 /p 〉 〈 p 〉 〈 strong 〉 52. Infant attachment and maternal depression as predictors of neurodevelopmental and behavioural outcomes at follow-up 〈 /strong 〉 〈 /p 〉 〈 p 〉 J Nothling, B Laughton, S Seedat 〈 /p 〉 〈 p 〉 〈 strong 〉 53. Differences in abuse, neglect and exposure to community violence in adolescents with and without PTSD 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 J Nothling, S Suliman, L Martin, C Simmons, S Seedat 〈 /p 〉 〈 p 〉 〈 strong 〉 54. Assessment of oxidative stress markers in children with autistic spectrum disorders in Lagos, Nigeria 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 Y Oshodi, O Ojewunmi, T A Oshodi, T Ijarogbe, O F Aina, J Okpuzor, O C F E A Lesi 〈 /p 〉 〈 p 〉 〈 strong 〉 55. Change in diagnosis and management of 'gender identity disorder' in pre-adolescent children 〈 /strong 〉 〈 /p 〉 〈 p 〉 S Pickstone-Taylor 〈 /p 〉 〈 p 〉 〈 strong 〉 56. Brain network connectivity in women exposed to intimate partner violence 〈 /strong 〉 〈 /p 〉 〈 p 〉 A Roos, J-P Fouche, B Vythilingum, D J Stein 〈 /p 〉 〈 p 〉 〈 strong 〉 57. Prolonged exposure treatment for PTSD in a Third-World, task-shifting, community-based environment 〈 /strong 〉 〈 /p 〉 〈 p 〉 J Rossouw, E Yadin, I Mbanga, T Jacobs, W Rossouw, D Alexander, S Seedat 〈 /p 〉 〈 p 〉 〈 strong 〉 58. Contrasting effects of early0life stress on mitochondrial energy-related proteins in striatum and hippocampus of a rat model of attention-deficit/ hyperactivity disorder 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 V Russell, J Dimatelis, J Womersley, T-L Sterley 〈 /p 〉 〈 p 〉 〈 strong 〉 59. Attention-deficit hyperactivity disorder in adults: A South African perspective 〈 /strong 〉 〈 /p 〉 〈 p 〉 R Schoeman, M de Klerk, M Kidd 〈 /p 〉 〈 p 〉 〈 strong 〉 60. Cognitive function in women with HIV infection and early-life stress 〈 /strong 〉 〈 /p 〉 〈 p 〉 G Spies, C Fennema-Notestine, M Cherner, S Seedat 〈 /p 〉 〈 p 〉 〈 strong 〉 61. Changes in functional connectivity networks in bipolar disorder patients after mindfulness-based cognitic therapy 〈 /strong 〉 〈 /p 〉 〈 p 〉 J A Starke, C F Beckmann, N Horn 〈 /p 〉 〈 p 〉 〈 strong 〉 62. Post-traumatic stress disorder, overweight and obesity: A systematic review and meta-analysis 〈 /strong 〉 〈 /p 〉 〈 p 〉 〈 strong 〉 〈 /strong 〉 S Suliman, L Anthonissen, J Carr, S du Plessis, R Emsley, S M J Hemmings, C Lochner, N McGregor L van den Heuvel, S Seedat 〈 /p 〉 〈 p 〉 〈 strong 〉 63. The brain and behaviour in a third-trimester equivalent animal model of fetal alcohol spectrum disorders 〈 /strong 〉 〈 /p 〉 〈 p 〉 P C Swart, C B Currin, J J Dimatelis, V A Russell 〈 /p 〉 〈 p 〉 〈 strong 〉 64. Irritability Assessment Model (IAM) to monitor irritability in child and adolescent psychiatric disorders. 〈 /strong 〉 〈 /p 〉 〈 p 〉 D van der Westhuizen 〈 /p 〉 〈 p 〉 〈 strong 〉 65. Outcome of parent-adolescent training in chilhood victimisation: Adaptive functioning, psychosocial and physiological variables 〈 /strong 〉 〈 /p 〉 〈 p 〉 D van der Westhuizen 〈 /p 〉 〈 p 〉 〈 strong 〉 66. The effect of ketamine in the Wistar-Kyoto and Sprague Dawley rat models of depression 〈 /strong 〉 〈 /p 〉 〈 p 〉 P J van Zyl, J J Dimatelis, V A Russell 〈 /p 〉 〈 p 〉 〈 strong 〉 67. Investigating COMT variants in anxiety sensitivity in South African adolescents 〈 /strong 〉 〈 /p 〉 〈 p 〉 L J Zass, L Martin, S Seedat, S M J Hemmings 〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉 〈 strong 〉 〈 br / 〉 〈 /strong 〉 〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉   〈 /p 〉 〈 p 〉   〈 /p 〉