While Rhodococcus equi (R. equi) remains the most common cause of subacute or chronic granulomatous bronchopneumonia in foals, development of a relevant model to study this bacterium has proven difficult. As a result, the reasons for the underlying foal’s susceptibility to this disease are not well understood. Furthermore, data regarding the immune response of foals to R. equi infection remains controversial. We hypothesized that foals are susceptible to R. equi early in life and that this susceptibility decreases with age. Also, we hypothesized that specific subclasses of IgG antibodies to the virulence-associated protein of R. equi, VapA, predict the outcome of exposure. The objectives of this study were: (1) to develop an R. equi challenge model that resulted in slow progressive disease in some foals as well as spontaneous regression of lesions in others, (2) using the developed model, to investigate the age-related susceptibility of young foals to R. equi, (3) to describe the humoral immune response of foals following experimental challenge and natural infection. The use of a low dose of R. equi to challenge neonatal foals resulted in slow, progressive disease characterized by pulmonary abscessation and spontaneous regression in approximately 50% of the foals. When this low dose was used in 1, 2 or 3-week-old foals, a marked decrease in disease susceptibility was observed as the foals aged. The immunological responses seen after experimental challenge reflect those observed after natural infection. While there was a significant increase of VapA-specific IgG and IgG subclasses over time in both pneumonic and healthy foals, use of VapA-specific IgG(T) showed good sensitivity and specificity when used as a diagnostic tool for R. equi pneumonia. In summary, this study shows that foal susceptibility to R. equi occurs early in life and decreases with age. Whereas all foals developed VapA-specific IgG antibodies post-exposure, IgG(T) appeared to be predictive of infection.

Voice-activated personal assistants (VAPA) har på senare tid blivit allt vanligare i dagligt bruk för individer. Då VAPA används som sökmotorer är det viktigt att de kan leverera ett svar som användaren upplever är av god kvalitet. Tidigare studier har genomfört kvantitativa tester för att undersöka svarskvaliteten i VAPA där användarens upplevelse inte tagits hänsyn till. Vi presenterar en studie ämnad för att fylla denna kunskapslucka. Genom en litteraturstudie togs fem grundteman fram, relevans, trovärdighet, läsbarhet, aktualitet och rikhet på innehåll, som ligger till grund för upplevelse av god svarskvalitet. Genom en intervjustudie med nio respondenter har deras upplevelse av VAPAs svarskvalitet undersökts baserat på litteraturstudiens teman. Utkomsten av studien är: (1) Studien visade på ett komplext samband mellan dessa teman, där några teman var beroende av andra teman. (2) Rikhet på innehåll visades ha motsatt effekt i en VAPA jämfört med traditionella sökverktyg, detta då rikheten i VAPA önskades vara kort och koncist snarare än att visa mycket innehåll. (3) I VAPA bör svaren vara i rätt svarsform för den ställda frågan, därmed bör svaren vara enkla, tydliga och inte innehålla onödig information såsom annonser som kan störa användaren i sökandet av ett svar. (4) Svarens trovärdighet är beroende av källornas rykten och användarens kunskap om källan, där vissa användare upplever blind tillit till vissa källor. / Voice-activated personal assistants (VAPA) have recently become more common in daily use for individuals. Because VAPAs are used as search engines, it is important that they can deliver an answer that the user feels is of good quality. Previous studies have conducted quantitative tests to examine the response quality in VAPA where the user experience has not been taken into account. We present a study intended to fill this knowledge gap. Through a literature study, five base themes were developed, relevance, credibility, readability, timeliness and richness of content, which is the basis for the experience of good response quality. Through an interview study with nine respondents, their experience of VAPA's response quality was investigated based on the literature study's themes. The results of the study are: (1) The study showed a complex relationship between these themes, where some themes were dependent on other themes. (2) Richness in content was shown to have the opposite effect in a VAPA compared to traditional search tools, as the richness in VAPA was desired to be short and concise rather than to show a lot of content. (3) The answers in VAPA should be in the correct form of answer for the question asked, thus the answers should be simple, clear and not contain unnecessary information such as advertisements that could disturb the user in the search for the answer. (4) The credibility of the answers depends on the sources' rumors and the user's knowledge of the source, where some users experience blind trust in certain sources.

Although Rhodococcus equi (R. equi), previously known as Corynebacterium equi, was first isolated from pneumonic foals almost a century ago, it remains the most common cause of subacute or chronic granulomatous bronchopneumonia in foals. While the majority of foals exposed to R. equi develop a protective immune response (regressors), others exhibit a unique susceptibility to infection (progressors). The determinants for either outcome are not completely understood. Therefore, current diagnostic and preventive measures are suboptimal and require betterment. In light of this current need, we hypothesized that immunoglobulin G subisotype T [IgG(T)] against the virulence-associated protein A (VapA) of R. equi, and whole blood cytokine expression profile of foals predict the outcome of infection and can be used as diagnostic markers of clinical disease. Further, we hypothesized that the use of R. equi hyperimmune plasma (HIP) decreases severity of disease in naturally infected foals, playing an important role in disease prevention in the field. Lastly, we hypothesized that specific anti-Rhodococcus equi pili antibodies passively acquired by foals via colostrum after immunization of pregnant mares with a Rhodococcus equi pili-based candidate vaccine will confer protection against induced disease, and therefore have an immediate impact on R. equi pneumonia prophylaxis. The objectives of this study were: (1) to describe the humoral immune response of progressor and regressor foals to R. equi following experimental challenge and natural infection, (2) to compare the cytokine and cell-marker expression profile in whole blood of progressor and regressor foals after challenge, (3) to evaluate the Vap-A specific IgG profile of a commercially available HIP product and its value as a prophylactic tool on an endemic farm, and (4) to evaluate the efficacy of a vaccine based on the Rhodococcus equi pili (Rpl). Although the IgG(T) response of progressor foals after challenge or following natural infection tended to be more pronounced than that observed in regressor foals, its performance as a diagnostic test for predicting disease outcome was poor. Likewise, whole blood cell-marker and cytokine expression profiles of progressor and regressor foals were not significantly different, undermining its reliability as a diagnostic tool. Evaluation of the association of HIP VapA specific IgG profile and rhodococcal disease outcome in the field resulted in the conclusion that progressor foals received significantly less VapA specific IgG, suggesting that HIP may have provided some protection to regressor foals. Although HIP appeared to have provided some protection against clinical pneumonia, Rpl maternally-derived IgG failed to confer any advantage to foals born from vaccinated mares. The Rpl candidate vaccine failed to confer protection to foals after challenge, and did not decrease disease severity in comparison to a control group. In summary, the results of this study do not support the use of VapA specific IgG(T) or whole blood cytokine expression profile as predictors of disease outcome. Further, our results suggest a positive effect of HIP on disease outcome. Lastly, the presence of systemic and local Rpl antibodies was not protective in foals.