Human factors: Predictors of avoidable wilderness accidents?

A common misconception is that wilderness adventure travel is risky owing to the nature of the objective dangers that are encountered, such as avalanches, rock falls, flash floods, failure of technical equipment and so forth. However, when one critically examines the proximal causes of wilderness accidents, even those caused by such ‘objective dangers’, it is apparent that many are due to ‘human factors’ or nontechnical skills. These are broadly defined as the continuous process of identifying and avoiding the activities, interactions and decisions that may jeopardise safe and effective response to adverse events. Objective dangers and adverse events are unavoidable, but the response to them is governed by how team dynamics, leadership and followership modes, situational awareness and experience may mitigate these risks or manage their consequences effectively. On the other hand, ignoring human factors during wilderness travel is predictive of wilderness accidents. This article outlines how an awareness of human factors may be used to reduce the risks of adventure travel significantly

Expedition medicine: A southern African perspective

A growing number of people are undertaking expeditions and adventure travel to previously inaccessible areas. The risks posed by increasing accessibility of remote regions and interest in extreme sports have not been fully obviated by modern equipment and communications. Therefore, there remains a requirement for medical care during wilderness expeditions, for which expectations and formal standards continue to increase. Expedition medicine should take cognisance of the predicted problems, plan for contingencies, and be practised pragmatically in austere settings. Southern African medics have a broad skill set, which makes them ideally suited to the field, but they should seek to understand the epidemiology of expeditions in different environments, undergo specialised training, and become involved in all phases of planning and execution of an expedition. Routine general practice complaints and accidental trauma are ubiquitous; travel medical issues such as blisters, diarrhoea, insomnia, sunburn and dehydration occur commonly; area/activity-specific issues such as  infectious disease risks and altitude illnesses must be addressed; and women’s health and dental problems are frequently overlooked. The expedition medic plays a wide range of roles, and should have knowledge and skills to match the requirements of the expedition. Fortunately, many resources exist to assist medics in becoming competent in the field

Acute high-altitude illness

A substantial proportion of South Africa (SA)’s population lives at high altitude (>1 500 m), and many travel to very high altitudes (>3 500 m) for tourism, business, recreation or religious pilgrimages every year. Despite this, knowledge of acute altitude illnesses is poor among SA doctors. At altitude, the decreasing ambient pressure proportionally decreases available oxygen (hypobaric hypoxia). This triggers both immediate respiratory compensation and gradual acclimatisation that occurs over days to weeks. Rapid ascents to altitudes above 2 500 m can precipitate acute altitude illness, including acute mountain sickness (AMS) and high-altitude pulmonary and cerebral oedema (HAPE and HACE). The best preventive measure is gradual ascent (no more than 300 - 500 m increase in sleeping altitude per day, with additional rest days for acclimatisation for every 1 000 m altitude gain), although chemoprophylaxis may speed acclimatisation. In the field, AMS, HAPE and HACE are diagnosed clinically. The Lake Louise Score questionnaire is used to elicit symptoms of AMS, and can be supplemented by assessing clinical signs such as tachycardia, tachypnoea, crepitations or ronchi, and ataxia. The mainstay of treatment for all but mild AMS is rapid descent to lower altitudes, which can be facilitated by administration of oxygen and drugs, including acetazolamide, dexamethasone and nifedipine, or use of a portable hyperbaric chamber

Guest Editorial: Growing wilderness and expedition medicine education in southern Africa

No Abstrac

Human factors: Predictors of avoidable wilderness accidents?

A common misconception is that wilderness adventure travel is risky owing to the nature of the objective dangers that are encountered, such as avalanches, rock falls, flash floods, failure of technical equipment and so forth. However, when one critically examines the proximal causes of wilderness accidents, even those caused by such ‘objective dangers’, it is apparent that many are due to ‘human factors’ or non-technical skills. These are broadly defined as the continuous process of identifying and avoiding the activities, interactions and decisions that may jeopardise safe and effective response to adverse events. Objective dangers and adverse events are unavoidable, but the response to them is governed by how team dynamics, leadership and followership modes, situational awareness and experience may mitigate these risks or manage their consequences effectively. On the other hand, ignoring human factors during wilderness travel is predictive of wilderness accidents. This article outlines how an awareness of human factors may be used to reduce the risks of adventure travel significantly

Expedition medicine: A southern African perspective

A growing number of people are undertaking expeditions and adventure travel to previously inaccessible areas. The risks posed by increasing accessibility of remote regions and interest in extreme sports have not been fully obviated by modern equipment and communications. Therefore, there remains a requirement for medical care during wilderness expeditions, for which expectations and formal standards continue to increase. Expedition medicine should take cognisance of the predicted problems, plan for contingencies, and be practised pragmatically in austere settings. Southern African medics have a broad skill set, which makes them ideally suited to the field, but they should seek to understand the epidemiology of expeditions in different environments, undergo specialised training, and become involved in all phases of planning and execution of an expedition. Routine general practice complaints and accidental trauma are ubiquitous; travel medical issues such as blisters, diarrhoea, insomnia, sunburn and dehydration occur commonly; area/activity-specific issues such as infectious disease risks and altitude illnesses must be addressed; and women’s health and dental problems are frequently overlooked. The expedition medic plays a wide range of roles, and should have knowledge and skills to match the requirements of the expedition. Fortunately, many resources exist to assist medics in becoming competent in the field

Acute high-altitude illness

A substantial proportion of South Africa (SA)’s population lives at high altitude (>1 500 m), and many travel to very high altitudes (>3 500 m) for tourism, business, recreation or religious pilgrimages every year. Despite this, knowledge of acute altitude illnesses is poor among SA doctors. At altitude, the decreasing ambient pressure proportionally decreases available oxygen (hypobaric hypoxia). This triggers both immediate respiratory compensation and gradual acclimatisation that occurs over days to weeks. Rapid ascents to altitudes above 2 500 m can precipitate acute altitude illness, including acute mountain sickness (AMS) and high-altitude pulmonary and cerebral oedema (HAPE and HACE). The best preventive measure is gradual ascent (no more than 300 - 500 m increase in sleeping altitude per day, with additional rest days for acclimatisation for every 1 000 m altitude gain), although chemoprophylaxis may speed acclimatisation. In the field, AMS, HAPE and HACE are diagnosed clinically. The Lake Louise Score questionnaire is used to elicit symptoms of AMS, and can be supplemented by assessing clinical signs such as tachycardia, tachypnoea, crepitations or ronchi, and ataxia. The mainstay of treatment for all but mild AMS is rapid descent to lower altitudes, which can be facilitated by administration of oxygen and drugs, including acetazolamide, dexamethasone and nifedipine, or use of a portable hyperbaric chamber

Neutrophil-derived reactive agents induce a transient SpeB negative phenotype in Streptococcus pyogenes

Background Streptococcus pyogenes (group A streptococci; GAS) is the main causative pathogen of monomicrobial necrotizing soft tissue infections (NSTIs). To resist immuno-clearance, GAS adapt their genetic information and/or phenotype to the surrounding environment. Hyper-virulent streptococcal pyrogenic exotoxin B (SpeB) negative variants caused by covRS mutations are enriched during infection. A key driving force for this process is the bacterial Sda1 DNase. Methods Bacterial infiltration, immune cell influx, tissue necrosis and inflammation in patient´s biopsies were determined using immunohistochemistry. SpeB secretion and activity by GAS post infections or challenges with reactive agents were determined via Western blot or casein agar and proteolytic activity assays, respectively. Proteome of GAS single colonies and neutrophil secretome were profiled, using mass spectrometry. Results Here, we identify another strategy resulting in SpeB-negative variants, namely reversible abrogation of SpeB secretion triggered by neutrophil effector molecules. Analysis of NSTI patient tissue biopsies revealed that tissue inflammation, neutrophil influx, and degranulation positively correlate with increasing frequency of SpeB-negative GAS clones. Using single colony proteomics, we show that GAS isolated directly from tissue express but do not secrete SpeB. Once the tissue pressure is lifted, GAS regain SpeB secreting function. Neutrophils were identified as the main immune cells responsible for the observed phenotype. Subsequent analyses identified hydrogen peroxide and hypochlorous acid as reactive agents driving this phenotypic GAS adaptation to the tissue environment. SpeB-negative GAS show improved survival within neutrophils and induce increased degranulation. Conclusions Our findings provide new information about GAS fitness and heterogeneity in the soft tissue milieu and provide new potential targets for therapeutic intervention in NSTIs.publishedVersio

The Sneeuberg: A new centre of floristic endemism on the Great Escarpment, South Africa

The Sneeuberg mountain complex (Eastern Cape) comprises one of the most prominent sections of the Great Escarpment in southern Africa but until now has remained one of the botanically least known regions. The Sneeuberg is a discrete orographical entity, being delimited in the east by the Great Fish River valley, in the west by the Nelspoort Interval, to the south by the Plains of Camdeboo, and to the north by the Great Karoo pediplain. The highest peaks range from 2278 to 2504 m above sea level, and the summit plateaux range from 1800 to 2100 m. Following extensive literature review and a detailed collecting programme, the Sneeuberg is reported here as having a total flora of 1195 species of which 107 (9%) are alien species, 33 (2.8%) are endemic, and 13 (1.1%) near-endemic. Five species previously reported as Drakensberg Alpine Centre (DAC) endemics are now known to occur in the Sneeuberg (representing range extensions of some 300–500 km). One-hundred-and-five species (8.8%) are DAC near-endemics, with the Sneeuberg being the western limit for most of these. Ten species (0.8%) represent disjunctions across the Karoo Interval from the Cape Floristic Region (CFR) to the Sneeuberg. In all, some 23 significant range extensions, eight new species, and several rediscoveries are recorded. We conclude by recognising the Sneeuberg as a new centre of endemism along the Great Escarpment, with floristic affinities with the Albany Centre and the DAC, and links to the CFR