Health problems of travellers: an examination of GeoSentinel and expedition data
Shaw, Marc (2009) Health problems of travellers: an examination of GeoSentinel and expedition data. Professional Doctorate (Research) thesis, James Cook University.
PDF (Front pages and extended abstract)
Childhood memories recall the endeavours of famous travellers in time whose moments of great occasion were often wrecked by diseases encountered on deployment. Take Genghis Khan, whose most indirect, though by no means benign, gift to the 13th century was the plague. Originating in the jungles of southern China and Burma, bubonic plague travelled with Mongol armies and then from caravan to caravan till it reached the Crimea in 1347. From there it would take a third of all Europeans.
Take this example as one of the human spread of disease and extend it to global travel in the 21st century. It is so much easier now to spread disease as travel is quicker, easier and many more people are partaking in it. Short incubation periods indicate the potential to promulgate disease processes is so much greater, and indeed with more disastrous effect. In addition, as there are so many different communicable diseases, there is the very real risk of mis-diagnosis with resultant dire consequences.
To focus energies on the prevention of traveller’s diseases would be akin to guiding good health in a way that supports not just the traveller, but the region of travel as well. To spotlight certain dis-ease, and diseases, in order to give clear examples of the work that goes into preventing traveller-health unwellness became, for the author, a logical nidus for energy. The projected outcome of such a fixation would be a set of parameters within which safe travel is possible.
Whilst not wanting to stifle travel with such apparent ‘rules’, popular thinking in the speciality of travel medicine has it that ‘guidelines for travel’ contribute to safe and secure travel, and also to diseases’ awareness with their resultant measures of prevention.
The stimulus to investigate illnesses that may affect travellers extended into those that may affect groups of people on collective journeys, and even those who were mounting expeditions to remote regions of the globe for venture or adventure. As it was not possible to be all encompassing with respect to the spectrum of travellers’ health diseases, it was important to acquire primary sentinels upon which to bass understanding of the disease processes and from them to make practical inference from the results.
This thesis thus centres on the general epidemiology of travel diseases and then seeks to investigate some focal aspects such as rabies immunisation, groups and expedition medicine, and incidental case studies to give clear example of the scope of this rather exciting field of medicine. From consideration of these examples, the development of policies on travel health management is a logical extension. Reviewing available data on outstanding issues such as: health of sportspeople at a major sporting event, vaccine preventable diseases and setting up a travel health clinic, is both exhilarating and intellectually challenging.
Enveloping all these aspects of travel medicine is personally energising and gives thought to clinical practice. It also gives energetic notice to want to pursue the field further in the future.
Methods of data collection and analysis were dependant upon the each of the three focus groups analysed. Firstly, those returning from their travels and who presented to travel health clinics in Auckland or Hamilton were assessed for illnesses acquired abroad. Secondly, those in the group targetted for either rabies pre-travel immunisation or port-travel rabies exposure were scoped in detail. Thirdly, the group that undertook remote travel by way of expeditions or premium travel tours were assessed for illnesses as they may have been obtained; viz, in the field. Some of these patients may have had a pre-travel consultation to anticipate overseas health issues from travel health professionals before they departed for overseas.
Global surveillance of emerging infections by way of a sentinel network enabled the collection of data for analysis of each of groups one and two, above. Being part of a expedition group, as the medical provider, guided the collection of information in group three. Group one was studied from 1997 until 2001. Group two from 1998 through until 2006. Finally, group three was studying from 2001 until 2004.
Recorded data for all patients presenting for travel-related illnesses, seen at the two sites in New Zealand, were extracted for analysis. Variables analysed included age, sex, pre-travel encounter, reason for travelling, patient classification (whether a New Zealander having returned from abroad, or a foreigner being assessed in New Zealand clinic ) and a post-travel diagnosis. In addition, patients with a diagnosis of animal-related injury (mammal bites or scratches) were included for analysis as a separate disease focus within the greater spectrum of general global ill health following travel abroad.
Patients seeking care for rabies post-exposure prophylaxis were also included. Data was collected on the following: gender, country and world region where exposure occurred, age of subject exposed, animal related to the exposure, site of exposure on the body, the World Health Organization category of exposure to potential rabies, pre-exposure prophylaxis status, post-exposure immunoglobulin given, post-exposure vaccine given, type of post-exposure vaccination regime and whether it was an approved vaccine, and finally, the presence or absence of travel health insurance.
The third group for micro-focused study in this thesis involved those going to remote global regions. From the commencement of the Sir Peter Blake Expedition to Brazil and Venezuela in 2001, the author (as expedition physician) recorded all illnesses and injuries amongst the crew and also amongst the indigenous people encountered, whilst undertaking the expedition. Information recorded included age, sex, subjective and objective nature of the presenting illness, the assessment of the condition based on presenting information and the treatment employed. The outcome of each presentation was tracked and follow-up was continuously maintained wherever possible.
There continues to be a growing popularity of travellers wishing to go on premium tours or expeditions, and little is known or written on the illnesses and injuries that may occur whilst travelling. Studies on the injuries and illnesses of various group-travels to countries such as may be encountered on the Silk Route in Middle Asia, the Arctic Circle, and the Mongolian Gobi are presented. All seek to investigate the prevalence of health problems suffered by travellers on a premium, expedition or remote medicine journey.
Information on travel-related illnesses, when reported through a global reporting system, can be useful for the travel health adviser in identifying issues of current concern. Diarrhoeal disease was assessed as being the most common diagnosis of illness in the returning traveller, followed by animal bites, skin diseases and schistosomiasis. Other tropical diseases however, such as malaria, were uncommon diseases amongst returning travellers. GeoSentinel, a global surveillance network, makes a significant contribution to the assessing emerging and re-emerging infectious diseases through a network of individual sites in various countries including New Zealand. Such information can be used to help provide preventive advice for travellers as well as help in assessing illness in post-travel patients.
Animal-associated injuries are not uncommon among returned travellers presenting to GeoSentinel sites. The highest proportion of potential rabies-exposure injuries was recorded in travellers to Asia, mostly in regions which are endemic for rabies, and this had led to a requirement for Post Exposure Prophylaxis. There is an inadequacy in current practice for rabies-exposed injured travellers, who need to be adequately counselled about animal-associated injuries and rabies risk when visiting rabies-infected countries. Concern must be expressed for the small number of travellers who were immunised prior to their travel, of whom a quarter were bitten overseas and received initial post-exposure treatment consistent with the World Health Organization guidelines. The risk of rabies in children younger than 8 years, who are at particular risk for animal bites requires particular attention; especially as this group represented nearly twenty percent of cases in this study. It is thus important that travellers from New Zealand are made aware of the risks of developing rabies secondary to animal exposure in countries they travel to, and all travellers need to obtain adequate pre-travel health advice, on the prevention of a disease that is virtually 100% fatal, from a qualified travellers’ health source.
Intradermal rabies immunisation appears very effective when given according to the standard WHO protocol in a cohort of intending New Zealand travellers. Thus, intradermal rabies immunisation is highly recommended for those travelling to endemic areas for the risk of rabies, particularly where follow-up serology can be done before travel and where there are staff who are experienced in this form of immunisation administration.
Exploration and adventure travel are increasingly attractive to people of widely differing ages, experience, physical health and interests. Whilst there are significant health challenges to practitioners of expedition medicine, the aims remain to anticipate preventable medical problems, to maintain health throughout the expedition, to optimise achievement and enjoyment, whilst not stifling enthusiasm or ambition. The modern practice of expedition medicine is to minimise the risk of trauma and diseases by proper pre-travel planning involving risk assessment, preventive measures such as vaccinations, prophylactic drugs and medical equipment, knowledge of first aid, emergency and primary healthcare skills, communication skills, and an attitude of caring for both the anticipated team and the anticipated cultures of the expedition. This planning should cover all contingencies; from mild illnesses and disease to group health insurances, through to unforeseen events such as evacuating a seriously ill, injured or dead person.
The inclusion of an expedition physician on an expedition increased the independence of the travelling group on their journeying, yet decreased the reliance on local health services, a source which is often scarce or absent on more remote location expeditions.
Conclusions Information changes quickly, and often dramatically. Anyone providing travel health information needs to be aware of the requirements of international travellers, for information on travel-related illnesses, when reported through a global reporting system, can be useful for the travel health adviser in identifying geographical diseases of global concern. Whilst illnesses and injuries encountered by international travellers tended to centre on ‘syndromic presentation’ of diarrhoeal, respiratory or dermatological illness, the travel health professional needs to be knowledgeable on their presentation. In being so, the clinician is acting as a clinical sentinel for transmissible disease processes. Being part of such a sentinel group makes a global contribution to the surveillance of emerging and re-emerging infectious diseases through a network of individual sites in various countries including New Zealand. This information can be used to help provide preventive advice for travellers as well as help in assessing illness in post-travel patients. Such is the case with the disease of rabies. There is increased awareness in New Zealand to make travellers aware of the risks of developing rabies secondary to animal exposure in countries they travel to.
As there is no clear distinction between those who travel either as expedition team members or others who travel to ‘wilderness’ areas, there is considerable overlap between adventure travel and leisure travel. Exploration and adventure travel are increasingly attractive to people of widely differing ages, experience, physical health and interests and this tends to create new challenges to practitioners of expedition medicine although the aims remain to anticipate preventable medical problems, to maintain health throughout the expedition, to optimise achievement and enjoyment, but above all not to stifle enthusiasm or ambition of the journey!