Anticipating the species jump: surveillance for emerging viral threats.

Zoonotic disease surveillance is typically triggered after animal pathogens have already infected humans. Are there ways to identify high-risk viruses before they emerge in humans? If so, then how and where can identifications be made and by what methods? These were the fundamental questions driving a workshop to examine the future of predictive surveillance for viruses that might jump from animals to infect humans. Virologists, ecologists and computational biologists from academia, federal government and non-governmental organizations discussed opportunities as well as obstacles to the prediction of species jumps using genetic and ecological data from viruses and their hosts, vectors and reservoirs. This workshop marked an important first step towards envisioning both scientific and organizational frameworks for this future capability. Canine parvoviruses as well as seasonal H3N2 and pandemic H1N1 influenza viruses are discussed as exemplars that suggest what to look for in anticipating species jumps. To answer the question of where to look, prospects for discovering emerging viruses among wildlife, bats, rodents, arthropod vectors and occupationally exposed humans are discussed. Finally, opportunities and obstacles are identified and accompanied by suggestions for how to look for species jumps. Taken together, these findings constitute the beginnings of a conceptual framework for achieving a virus surveillance capability that could predict future species jumps.

Comparison of the 25-gauge Whitacre with the 24-gauge Sprotte spinal needle for elective caesarean section: cost implications.

Spinal anaesthesia provides rapid, safe anaesthesia for Caesarean section. The pencil-point spinal needles (Sprotte and Whitacre) are reported to have a low incidence of post-dural puncture headache (PDPH). As the 25G Whitacre is less expensive than the 24G Sprotte needle, this prospective, randomized, double-blind study was designed to compare the incidence of PDPH and ease of insertion of these needles in 304 ASA 1 and 2 women having elective Caesarean section under spinal anaesthesia. Each patient was assessed daily for five consecutive days following Caesarean section by an investigator blinded to the needle used. The results indicate that the two needles have a similar ease of insertion, number of failed insertions, and failed subarachnoid blockade. An inability to insert the spinal needles occurred in two patients in each group. Therefore, 150 patients in each group completed the study. The incidence of PDPH with the 24G Sprotte needle was 4.0% (6/150) compared with 0.66% (1/150) with the 25G Whitacre (NS). There was no correlation between the occurrence of PDPH and the difficulty of needle insertion, presence of transient hypotension or the effectiveness of anaesthesia delivered. This study indicates that both needles are comparable with respect to ease of insertion and incidence of PDPH. As the Whitacre needle is less expensive it is a reasonable alternative to the more expensive Sprotte needle.

Anaesthetic management of a complex morbidly obese parturient.

A case is presented of a morbidly obese parturient who had multiple medical problems. She had angina and was receiving nitrate therapy, had insulin-dependent diabetes mellitus, hypertension, asthma and benign intracranial hypertension (pseudotumour cerebri). Lumbar epidural analgesia was chosen for labour and delivery and resulted in an uneventful outcome.

Anaesthetic management of patients with placenta accreta.

The management of a 28-year-old primigravida with placenta accreta diagnosed during Caesarean section is described. A hysterectomy was required to control massive haemorrhage, and the patient made a full recovery. The increased incidence of placenta accreta over the last three decades is thought to be associated with the concomitant increased frequency of Caesarean section, resulting in an increased incidence of placenta praevia (1.9 per cent to 3.9 per cent). Patients with placenta praevia who have had a previous Caesarean section have a remarkably increased risk of placenta accreta. Management of placenta accreta is primarily by control of haemorrhage on delivery of the placenta. Control can be assisted by infrarenal cross-clamping of the aorta and/or intra-myometrial injection of prostaglandin F2 alpha which produces myometrial and vascular contraction. Identification of patients at increased risk, preparation for treatment and effective treatment of placenta accreta will minimize maternal morbidity and mortality.

Anaesthetic management and non-invasive monitoring for caesarean section in a patient with cardiomyopathy.

This paper describes the anaesthetic management of a 29-year-old woman for an elective repeat Caesarean section. A diagnosis of peripartum cardiomyopathy (PPCM) had been made after her first delivery by Caesarean section three years earlier. Although the patient was currently asymptomatic, recent echocardiography demonstrated persistent left ventricular dilatation. The choice of haemodynamic monitors and the clinical significance of PPCM in this situation are discussed.

Quantitative one-stage assays for factors V and X.

The relative sensitivities of the prothrombin time, Russell's viper venom time and activated partial thromboplastin time were determined in one-stage quantitative assays for factor V and factor X. Sensitivity was defined as the slope of the reference curve. The prothrombin time was the most sensitive test for factor X and the least sensitive for factor V. The Russell's viper venom time was the most sensitive test for factor V and least sensitive for factor X. The activated partial thromboplastin time approximated the sensitivity of Russell's viper venom for factor V and had intermediate sensitivity for factor X. The data indicate that factor V is best quantitated by the Russell's viper venom time and factor X by the prothrombin time, exactly the opposite of what is customarily done.