Pharmacological treatment for mental health illnesses in adults receiving dialysis: A scoping review.

BACKGROUND: Pharmacologic management of mental health illnesses in patients receiving dialysis is complex and lacking data. OBJECTIVE: Our objective was to synthesize published data for the treatment of depression, bipolar and related disorders, schizophrenia or psychotic disorders, and anxiety disorders in adults receiving hemodialysis or peritoneal dialysis. METHODS: We undertook a scoping review, searching the following databases: Medline, Embase, CINAHL, PsycINFO, Cochrane Library, Scopus, and Web of Science. Data on patients who received only short-term dialysis, a kidney transplant, or non-pharmacologic treatments were excluded. RESULTS: Seventy-three articles were included: 41 focused on depression, 16 on bipolar disorder, 13 on schizophrenia and psychotic disorders, 1 on anxiety disorders, and 2 addressing multiple mental health illnesses. The majority of depression studies reported on selective serotonin reuptake inhibitors (SSRIs) as a treatment. Sertraline had the most supporting data with use of doses from 25 to 200 mg daily. Among the remaining SSRIs, escitalopram, citalopram, and fluoxetine were studied in controlled trials, whereas paroxetine and fluvoxamine were described in smaller reports and observational trials. There are limited published data on other classes of antidepressants and on pharmacological management of anxiety. Data on treatment for patients with bipolar disorder or schizophrenia and related disorders are limited to case reports. CONCLUSION: Over half of the studies included were case reports, thus limiting conclusions. More robust data are required to establish effect sizes of pharmacological treatments prior to providing specific recommendations for their use in treating mental health illnesses in patients receiving dialysis.

Epidemiology of ticks submitted from human hosts in Alberta, Canada (2000-2019).

ABSTRACTThe geographic range and occurrence of tick species is dynamic. This has important public health implications due to important tick species that can transmit pathogens. This study presents a retrospective review of tick genera recovered from humans and submitted for identification in Alberta, Canada, over a 19-year period. The total number of ticks and proportion of genera were analyzed over time. Molecular testing for a number of pathogens associated with Ixodes scapularis and I. pacificus was conducted. A total of 2,358 ticks were submitted between 2000 and 2019, with 98.6% being acquired in Alberta. The number of ticks submitted increased significantly over time (p < 0.0001). Dermacentor ticks were the most abundant genus, followed by Ixodes and Amblyomma. There was a significant decrease in the proportion of Dermacentor ticks between 2013 and 2019 (p = 0.02), with a corresponding increase in the proportion of Ixodes ticks over the same time (p = 0.04). No statistically significant change in seasonality was identified. Borrelia burgdorferi was detected in 8/76 (10.5%; 95% CI 5.4-19.4%) of all I. scapularis and I. pacificus ticks submitted. This translated to a B. burgdorferi positivity of 0.35% (95% CI 0.15-0.68%) among all ticks received. Dermacentor species (especially D. andersoni) remains the most common tick feeding on humans in Alberta. Small numbers of vector species (including I. scapularis/pacificus) are encountered annually over widely separated geographic areas in the province. The risk of exposure to tick-borne pathogens (e.g. Lyme disease) in Alberta remains low.

Endosymbiotic Male-Killing Spiroplasma Affects the Physiological and Behavioral Ecology of Macrocheles-Drosophila Interactions.

While many arthropod endosymbionts are vertically transmitted, phylogenetic studies reveal repeated introductions of hemolymph-dwelling Spiroplasma into Drosophila. Introductions are often attributed to horizontal transmission via ectoparasite vectors. Here, we test if mites (Macrocheles subbadius) prefer to infect Spiroplasma poulsonii MSRO (Melanogaster sex ratio organism)-infected flies and if MSRO infection impairs fly resistance against secondary mite attack. First, we tested if mites prefer MSRO+ or MSRO- flies using pairwise choice tests across fly ages. We then tested whether mite preferences are explained by changes in fly physiology, specifically increased metabolic rate (measured as CO2 production). We hypothesize that this preference is due in part to MSRO+ flies expressing higher metabolic rates. However, our results showed mite preference depended on an interaction between fly age and MSRO status: mites avoided 14-day-old MSRO+ flies relative to MSRO- flies (31% infection) but preferred MSRO+ flies (64% infection) among 26-day-old flies. Using flowthrough respirometry, we found 14-day-old MSRO+ flies had higher CO2 emissions than MSRO- flies (32% greater), whereas at 26 days old the CO2 production among MSRO+ flies was 20% lower than that of MSRO- flies. Thus, mite preferences for high-metabolic-rate hosts did not explain the infection biases in this study. To assess changes in susceptibility to infection, we measured fly endurance using geotaxis assays. Older flies had lower endurance consistent with fly senescence, and this effect was magnified among MSRO+ flies. Given the biological importance of male-killing Spiroplasma, potential changes in the interactions of hosts and potential vectors could impact the ecology and evolution of host species. IMPORTANCE Male-killing endosymbionts are transmitted from mother to daughter and kill male offspring. Despite these major ecological effects, how these endosymbionts colonize new host species is not always clear. Mites are sometimes hypothesized to transfer these bacteria between hosts/host species. Here, we test if (i) mites prefer to infect flies that harbor Spiroplasma poulisoni MSRO and (ii) flies infected with MSRO are less able to resist mite infection. Our results show that flies infected with MSRO have weaker anti-mite resistance, but the mite preference/aversion for MSRO+ flies varied with fly age. Given the fitness and population impacts of male-killing Spiroplasma, changes in fly-mite interactions have implications for the ecology and evolution of these symbioses.

Extending the ecology of fear: Parasite-mediated sexual selection drives host response to parasites.

The 'ecology of fear' describes the negative effects natural enemies have on potential victims even when those victims are not consumed or infected. Although recent work has demonstrated parasites have non-consumptive effects (NCE) on potential hosts, how these effects vary within host populations is not well understood. We investigated how NCE vary based on host risk of infection and relative cost of infection by measuring the metabolic rate (MR) of naive Drosophila nigrospiracula exposed to an ectoparasite, Macrocheles subbadius. We tested two mutually exclusive hypotheses: 1) asymmetrical costs of infection drive adaptions for stronger responses to parasite exposure; or 2) asymmetrical risks of infection drive adaptions for stronger responses to parasite exposure. In this system, male flies have higher costs of infection relative to female flies due to parasite-mediated sexual selection; similarly, virgin females experience higher costs of infection relative to mated females. Risk of infection also varies among flies because mites preferentially infect female flies over males, and mites preferentially infect mated females over virgin females. Our results were compatible with the hypothesis that costs of infection drive the strength of response to mite risk. Female flies responded to parasite exposure with a 15.1% increase in MR, while exposed males showed a stronger response with a 31.3% increase in MR. Mated females increased their MR by 34.8% during mite exposure whereas virgin females experienced an increase of 61.2%. Our findings suggest that NCE of parasites can vary based on state-dependent costs of infection.

Ecology of fear: environment-dependent parasite avoidance among ovipositing Drosophila.

Habitat avoidance is an anti-parasite behaviour exhibited by at-risk hosts that can minimize exposure to parasites. Because environments are often heterogeneous, host decision-making with regards to habitat use may be affected by the presence of parasites and habitat quality simultaneously. In this study we examine how the ovipositing behaviour of a cactiphilic fruit fly, Drosophila nigrospiracula, is affected by the presence of an ectoparasitic mite, Macrocheles subbadius, in conjunction with other environmental factors - specifically the presence or absence of conspecific eggs and host plant tissue. We hypothesized that the trade-off between site quality and parasite avoidance should favour ovipositing at mite-free sites even if it is of inferior quality. We found that although flies avoided mites in homogeneous environments (86% of eggs at mite-free sites), site quality overwhelmed mite avoidance. Both conspecific eggs (65% of eggs at infested sites with other Drosophila eggs) and host plant tissue (78% of eggs at infested sites with cactus) overpowered mite avoidance. Our results elucidate the context-dependent decision-making of hosts in response to the presence of parasites in variable environments, and suggest how the ecology of fear and associated trade-offs may influence the relative investment in anti-parasite behaviour in susceptible hosts.

Host Respiration Rate and Injury-Derived Cues Drive Host Preference by an Ectoparasite of Fruit Flies.

Host bioenergetics and energy fluxes can be applied to measure the ecological and physiological effects of parasitism. By measuring changes in host metabolic rate, one can estimate the physiological costs of infection. Additionally, metabolic rate dictates the rate of resource conversion within a host and, by extension, the resources available to a parasite. We hypothesize that parasites are selected to respond to cues that indicate high resource availability, that is, host metabolic state. We investigated whether an ectoparasite mite (Macrocheles subbadius) can differentiate between potential hosts (Drosophilia nigrospiracula) on the basis of relative carbon dioxide output as measured by respirometry. In pairwise choice tests, mites were allowed to choose between two size-matched fruit flies with differing metabolic rates or levels of CO2 output. Our results showed that mites preferentially infect flies with relatively higher respiration rates. Accordingly, we investigated whether fly respiratory rate (measured by CO2 production) changes in response to injury, potentially explaining a previously reported preference for injured flies. We also tested whether chemical cues released during injury influence preference for injured hosts. We determined that fly exudate (mostly consisting of hemolymph) applied to an uninjured fly released at the site of injury significantly increased the likelihood of infection, but injury did not significantly change the CO2 output of the flies. Our results suggest that parasites are relying on chemical cues not only for host finding but also to discriminate between hosts on the basis of the rate of respiration, with potentially important implications for the metabolic theory of ecology.