Why Are There So Few Rickettsia conorii conorii-Infected Rhipicephalus sanguineus Ticks in the Wild?

The bacterium Rickettsia conorii conorii is the etiological agent of Mediterranean spotted fever (MSF), which is a life-threatening infectious disease that is transmitted by Rhipicephalus sanguineus, the brown dog tick. Rh. sanguineus-R. conorii conorii relationships in the wild are still poorly understood one century after the discovery of the disease. In this study, we collected naturally infected ticks from the houses of people afflicted by MSF in Algeria. Colonies of both infected and non-infected ticks were maintained in our laboratory, and we studied the effect of temperature variations on the infected and non-infected ticks. We did not observe any major differences between the biological life cycle of the infected and non-infected ticks held at 25°C. However, a comparatively higher mortality relative to the control group was noticed when R. conorii conorii-infected engorged nymphs and adults were exposed to a low temperature (4°C) or high temperature (37°C) for one month and transferred to 25°C. R. conorii conorii-infected Rh. sanguineus may maintain and serve as reservoirs for the Rickettsia if they are not exposed to cold temperatures. New populations of ticks might become infected with Rickettsiae when feeding on a bacteremic animal reservoir

Stepped care treatment for depression and anxiety in primary care. a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Depressive and anxiety disorders are common in general practice but not always treated adequately. Introducing stepped care might improve this. In this randomized trial we examined the effectiveness of such a stepped care model.</p> <p>Methods</p> <p>The study population consisted of primary care attendees aged 18-65 years with minor or major DSM-IV depressive and/or anxiety disorders, recruited through screening. We randomized 120 patients to either stepped care or care as usual. The stepped care program consisted of (1) <it>watchful waiting</it>, (2) <it>guided self-help</it>, (3) short face-to-face <it>Problem Solving Treatment </it>and (4) <it>pharmacotherapy and/or specialized mental health care</it>. Patients were assessed at baseline and after 8, 16 and 24 weeks.</p> <p>Results</p> <p>Symptoms of depression and anxiety decreased significantly over time for both groups. However, there was no statistically significant difference between the two groups (IDS: <it>P </it>= 0.35 and HADS: <it>P </it>= 0.64). The largest, but not significant, effect (<it>d </it>= -0.21) was found for anxiety on T3. In both groups approximately 48% of the patients were recovered from their DSM-IV diagnosis at the final 6 months assessment.</p> <p>Conclusions</p> <p>In summary we could not demonstrate that stepped care for depression and anxiety in general practice was more effective than care as usual. Possible reasons are discussed.</p> <p>Trial Registration</p> <p>Current Controlled Trails: <a href="http://www.controlled-trials.com/ISRCTN17831610">ISRCTN17831610</a>.</p