Interpreting paired serology for Ross River virus and Barmah Forest virus diseases.

BACKGROUND: Ross River virus (RRV) and Barmah Forest virus (BFV) cause approximately 4000 and 1000 cases, respectively, of rheumatic disease in Australia every year. Confirmation of a diagnosis usually involves testing for virus-specific immunoglobulin (Ig) M and IgG by a National Association of Testing Authorities-accredited pathology facility. OBJECTIVE: The aim of the article is to provide a logical framework by which clinicians can interpret paired RRV and BFV serology results in environments in which numerical antibody titres are no longer routinely provided. The traditional recommendation to look for an increase in titres is now largely obsolete. DISCUSSION: Paired serology is clinical best practice but needs to be appropriately interpreted given the false positive and negative rates, the large number of asymptomatic infections and the long-term persistence of IgM in some individuals. An inappropriate interpretation risks a misdiagnosis.

Successful post-exposure prophylaxis of Ebola infected non-human primates using Ebola glycoprotein-specific equine IgG.

Herein we describe production of purified equine IgG obtained from horses immunized with plasmid DNA followed by boosting with Kunjin replicon virus-like particles both encoding a modified Ebola glycoprotein. Administration of the equine IgG over 5 days to cynomolgus macaques infected 24 hours previously with a lethal dose of Ebola virus suppressed viral loads by more than 5 logs and protected animals from mortality. Animals generated their own Ebola glycoprotein-specific IgG responses 9-15 days after infection, with circulating virus undetectable by day 15-17. Such equine IgG may find utility as a post-exposure prophylactic for Ebola infection and provides a low cost, scalable alternative to monoclonal antibodies, with extensive human safety data and WHO-standardized international manufacturing capability available in both high and low income countries.

Guide-wire fragment embolisation in paediatric peripherally inserted central catheters.

OBJECTIVE: To report guide-wire fragment embolisation of paediatric peripherally inserted central catheter (PICC) devices and explore the safety profile of four commonly used devices. DESIGN, SETTING AND PARTICIPANTS: Clinical incidents involving paediatric PICC devices in Queensland public hospitals were reviewed. A PICC user-experience survey was conducted at five public hospitals with 32 clinicians. A device design evaluation was undertaken, and magnetic resonance imaging (MRI) safety was tested by a simulation study. MAIN OUTCOME MEASURES: Embolisation events; technical mistakes, multiple attempts and breakages during insertion; willingness to use the device; failure modes and risk priority rating; movement and/or temperature change on exposure to MRI. RESULTS: Six clinical incidents of silent guide-wire embolisation, and four near misses were identified; all were associated with one type of device. The survey found that this device had a reported broken-wire embolisation rate of 0.9/100 insertions with no events in other devices; two of the four devices had a higher all-cause embolisation rate (3.3/100 insertions v 0.4/100 insertions) and lower clinician acceptance (68%-71% v 91%-100%). All devices had 6-17 identified failure modes; the two devices that allowed removal of a guide wire through a septum had the highest overall risk rating. Guide-wire exposure to MRI was rated a potential safety risk due to movement. CONCLUSIONS: There is marked variation in the safety profile of 3 Fr PICC devices in clinical use, and safety performance can be linked to design factors. Pre-MRI screening of all children who have previously had a PICC device inserted is recommended. We advocate a decision-making model for evaluation of device safety.