Wilderness exposure is associated with a set of potential infections that recreational travellers may acquire from contaminated food and water, as well as from exposure to animals and arthropods. When heading out to play, most people in good health should not be unduly burdened with the potential of contracting an infection. Many individuals have reported extensive travel and outdoor activities and have never risked any illness more serious than the common cold. However, the consequences of acquiring a travel-associated infection can curtail activities for weeks and could require a substantial visit to the physician and significant antibiotic treatment.

This burden of illness is the real cost to outdoor enthusiasts of acquiring a travel-acquired infection. The section offers general advice about preventing wilderness infections and strategies for promoting infection prevention programs. The first step in convincing people to change behaviour is to create an awareness of the risk within a susceptible audience. Before developing a comprehensive plan for the prevention of infections in the wilderness, it is important to understand the types of infections individuals are likely to encounter. Given the prevalence of ticks in the Midwest, the infectious diseases most likely to be encountered in a wilderness setting in the Midwest must also be in the mind of the physician planning for the wilderness experience. In addition to promoting general safe practices for living and working outdoors, including pre-and post-exposure immunization regimens, clinicians can provide essential advice on the management of specific problem areas that may confront research teams in the bush.

Understanding Common Wilderness Infections

Pathogens, or disease-producing organisms, are more diverse than people typically realize. Major categories of pathogens include viruses, bacteria, fungi (including moulds and yeast), and parasites (which include protozoa and worms). In human bodies, it is normal to have microorganisms that cause infections in moderate amounts, their territories held in check by the healthy human immune response as well as helpful or “commensal” microorganisms that do not cause infections. Infections may result from exposure to pathogens at high enough dose levels to defeat healthy mucous membranes and/or skin – this is why it’s crucial to understand routes of transmission; the presence of ineffective mucous membranes due to dehydration in a wilderness context; turning off or suppression of the immune system due to dehydration and electrolyte imbalance; and hyperexposure or lack of sleep, paired with strenuous exercise and/or exposure to cold or heat.

Infection signs and symptoms can be general or organ-specific. Inflammation, fevers, swollen lymph glands, muscle aches, diarrhoea, and fatigue all relate to the body generally responding to invasion by pathogens. The likelihood of exposure and signs of the infection, as well as hysteria, coincides with the season of the year. Overall, mortality from “wilderness” infections is low in most countries. However, this fact has led some to dismiss the threat. This is a dangerous attitude. Even “minor” infections can become serious, resulting in hospitalization and long-term disability. Failure to properly treat even simple diarrhoea can lead to life-threatening dehydration. Current best practice for wilderness emergency personnel and trip leaders is to err on the side of caution concerning wilderness infections. Researched and proven infection rates in the wilderness are, by definition, lower than the true-world rate because only cases severe enough to bring people to medical attention are captured in the research studies. This is why such studies are extremely imprecise and undependable for setting policies, standards, or “best practices” for wilderness medicine.

Bacterial Infections

Infections suffered in a wilderness setting can be broken down into different categories based on their etiologies. The most common infections found in such rural environments—bacterial infections affecting the skin and soft tissue and those related to the ingestion of contaminated food or water—will be discussed in separate sections. Bacterial infections. Many different bacteria have been shown to cause infections of the skin and the soft tissues beneath it. Such infections were traditionally believed to be caused by pathogenic organisms. However, a dermatologist found that skin infections could be caused by common organisms. More recently, a survey of clinicians found that almost 30% believed we were in the middle of an epidemic of skin and soft tissue infections, many of which are cellulitis.

Humans can come into contact with such bacteria from many different water sources while in the wilderness. Small cuts and abrasions serve as pathways by which such bacteria can enter the skin, where they can cause local infections. State park rangers found that minor wounds acquired by people in the wild were the strongest risk factor for the development of cellulitis. Additionally, animal bites have been recognized as a risk factor for the development of another skin infection—which can be caused by the same bacteria associated with cellulitis. Thus, the nexus between our fast-paced lifestyle and the escalating popularity of outdoor activities is that more and more non-immune individuals are being exposed to disease vectors mentioned above and thus may serve as a source of such agents if they live in nature.

Viral Infections

Among the many viral pathogens that can affect individuals in wilderness settings are hantavirus and West Nile virus. Hantavirus is primarily spread through inhaling the urine, droppings, and saliva, or direct contact with rodents carrying the virus. In addition, several enzymes present in the pulmonary endothelium make it an ideal site for viral replication. This ailment can result in hantavirus pulmonary syndrome and hemorrhagic fever with renal syndrome that can lead to death if not treated. The West Nile virus is transmitted by mosquitoes and can have severe to no symptoms in 80% of those who become infected. The remaining 20% of the population will develop West Nile fever or West Nile neuroinvasive disease. Symptoms may include headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness, and paralysis, and can be fatal.

To prevent both hantavirus and West Nile virus, you can employ several preventative strategies. Rodent diets are influenced by the environment and can influence the viral load and how quickly the virus clears from the host. Remember to use tent floors, close tent zippers, and don’t set up camp near rodent droppings because hantavirus can last longer in hot, dry conditions. There are no known cures or vaccines for these illnesses, so the best form of prevention is to safeguard your health by using standard infection control measures including washing hands, using appropriate drinking water, and avoiding contact with animal droppings. An additional safeguarding tip includes using insect repellent containing at least 20-30% DEET and removing standing pools of water, which are mosquito breeding grounds.

Parasitic Infections

In the wilderness, people can encounter an increase in parasitic infections. Amoebiasis, ascariasis, pathogenic taeniasis, filariasis, giardiasis, leishmaniasis, malaria, and toxoplasmosis are some of the parasitic diseases that affect outdoor enthusiasts. Parasites can be transmitted by ingestion, inhalation, or contact with infected faeces, urine, and other body fluids from an animal or person. Regarding parasitic foundations and transmission, infections from anaerobic protozoa can be transmitted to humans and animals directly through soil and infected water.

Some ways to reduce the prevalence of parasites are to use protective footwear as well as leather gloves. Outdoor enthusiasts should drink and use water extracted at least 30.5 meters away from the water to perform fine sieves. In the outdoors, people can also lessen contact with parasites by avoiding direct contact and maintaining a habit of washing their hands. Numerous parasitic diseases can be contracted in the wilderness, and in general, treatments are available. Detection of parasitic diseases at an early stage is pivotal for the treatment of these diseases. Prairie settings can strengthen the potential spread of parasitic diseases and place populations at substantial risk for infection. The life cycles of parasites are imperative in establishing effective management and treatment of parasites. Dispersing information on preventable methods of exposure to parasites is essential to decrease exposure to these diseases. Some doctors indicated that physicians should keep in mind that these parasite organisms are on earth and can cause diseases in healthy people.

Fungal Infections

While the overall risk of fungal infections in wilderness environments is small, perhaps the single greatest risk is associated with the active transmission of fungal infections of the skin. Ringworm and athlete’s foot are common infections that are typically caused by filamentous fungi known as dermatophytes. These fungi can be transmitted from infected individuals to others or to objects where they can survive for some time. Infected persons will frequently have an itchy, raised rash with a scaly border. A fungal infection of the fingernails or toenails can begin as a tinea pedis infection and infect the nail when the skin and nail separation or injury occurs. Other manifestations of fungal infections that may be seen include tinea cruris, tinea faciei, tinea barbae, and cutaneous candidiasis, among others. In general, fungal infections that are seen in the skin where there are warm, dark, and moist conditions will exist.

While the climate in a wilderness environment may not increase the risk of these conditions, the temperature, humidity, moisture, and dampness of a wilderness environment can increase the risk of other types of fungal infections. These fungi are commonly found in the environment and may pose a risk in some wilderness environments. Multiple activities may increase the relative risk for infection, including wading or swimming in water, exposure of the feet to be dry or damp for long periods, and sharing items of personal care with others. The relative damage caused by these fungi is less, and infections should not be any more concerning than those that occur in non-wilderness environments. It is important to note that if the treatment of fungal infections is delayed or incomplete, complications of these infections can occur outside of care and may alter travel plans. Generally, a good level of hygiene can be maintained in these environments by washing the affected areas twice daily and drying the area thoroughly. Using an antifungal cream or powder at this stage can only help. Although the risk of fungal infections in most wilderness settings is generally low, an awareness of specific fungal threats is important. An increased level of vigilance may be required, mainly in areas with high humidity, where fungal pathogens that can cause very severe infections are present. Local knowledge is important to avoid infecting specific pathogens. Prompt treatment and early diagnosis of skin and eye conditions are recommended, as delaying treatment can lead to much more severe infections. All fungal skin and eye infections are more difficult to treat and can take longer to heal once they progress to a severe condition.

Pre-Trip Preparation

A variety of steps can be taken to prevent the occurrence of infections in the wilderness. Pre-trip preparation is one of the most critical aspects of risk minimization. Travelers should schedule a visit with a healthcare provider experienced in travel medicine for a pre-travel health assessment at least 4-6 weeks before their trip. This appointment not only allows time for any necessary vaccinations to become protective but also provides an occasion to thoroughly discuss preventive practices. Ensuring that basic essential vaccinations are up to date before travel is another method of preventing infections. These include inoculation for measles, mumps, rubella, diphtheria, pertussis, tetanus, polio, varicella, and annual influenza.

To conduct an informed discussion with a travel medicine practitioner, travellers must be aware of their proposed itinerary. Comprehensive, region-specific information for the area to be visited is available from several reputable sources. Preparing a basic medical and dental kit and adding or removing specific items based on the planned activities and the destination will help ensure that useful supplies are on hand. These may include sunscreen, first aid materials, antidiarrheals, and personal medications. After deciding to consult a travel professional and discuss the proposed itinerary, a traveller may feel more secure, better educated about potential health risks, and better able to make decisions about personal risk. Providing knowledge allows travellers to take control of their health and well-being. It is critical to remember that to protect oneself from dangers, one should think ahead. It takes time to collect and prepare the necessary equipment and paperwork. While it may seem unlikely, in true medical emergencies everything in the medical kit may become crucial. Thus, the kit must be tailored to the traveller's specific travel itinerary and individual needs. It may become the most valuable possession when delays occur.

Health Assessment and Vaccinations

People planning a remote trek or backcountry trip should have a thorough health assessment to identify medical issues that may increase their risk of infection. Information is available about the relative infection risk that individuals with various chronic conditions face, including pace, epidemiology, and long-term risks, as well as strategies to decrease these risks. The traveller should know about the environment ahead of time to recommend the appropriate vaccinations. Personalized prophylactic measures are available from travel health clinics and infectious disease experts. As part of a health assessment, travellers should discuss their specific plans with a health professional and be vaccinated as required; vaccinations and immune globulins are often needed to prevent tick-borne encephalitis in non-hyperendemic areas, as well as to prevent other infections.

During a pre-trip medical consultation, travellers can learn about the environmental or regional risks and obtain vaccinations, which can necessitate time for the body to build immunity. The assessment should take into account the visitor's medical conditions, such as gastroesophageal reflux disease, renal disease, and cancer or HIV infection, because various infections can be more severe in these individuals, i.e., leading to chronic disease. People who may be more susceptible to particular infections due to methods they use to purify their water should be aware of those risks. As a result, they will understand how to prevent disease.

Packing Essential Medical Supplies

As a resource to individuals who are in remote, wilderness, or other austere environments, you must pack critical medical supplies with you before you go. Experienced healthcare providers could write whole textbooks about what are the best and most practical items to pack, and provide exhaustive discussion around the finer points of austere medical care. However, these are not intended to be exhaustive medical manuals, and sometimes a bit of knowledge is dangerous. Therefore, the information provided herein is most certainly not a crash course in wilderness medicine but is intended to give you some basic guidance regarding what types of items you should – and should not – consider bringing. Packing Tips: As cliché as it sounds, our first tip is "don't overpack"! There's no sense in bringing excessive medical gear with you, unless perhaps you possess an almost unbelievable amount of strength and stamina, or are going on a journey of such length and difficulty and with such an incredibly high potential for injury that common medical supplies will become exhausted. Our second tip is that you should "customize" your kit, based on your activities, personal health status, and the risks you are likely to encounter. For example, the types of kits you might pack for a week-long backpack trip during mid-summer are incredibly different than for a six-week-long mountaineering expedition in winter. Third, remember that you need to know how to use the items in your kit before you have to use them. Practice, whenever possible, before you need them for real – and make any necessary adjustments in your kit based on real-world training.

Hygiene Practices in the Wilderness

Perhaps the most effective way to mitigate infection risk is to practice personal hygiene. Many organisms, including Streptococcus, Staphylococcus, E. coli, and hepatitis viruses, can be transmitted by hand. Wilderness travellers should have access to and wash with a mild, unscented surfactant soap and water (or use an alcohol-based hand rub) after urination, bowel movements, and toileting. Hands should be clean after touching or engaging with animals, before food preparation, and before eating. Good personal hygiene recommendations also include burying human waste at least 200 feet away from lakes or streams. Do not wash in water sources that are near tents or areas of water collection, as soap can contribute to pollution. The general rule is to dig a hole 6 to 8 inches deep and to replace the soil when covering human waste. As in everyday life, using a tissue to catch sneezes and coughs, and out of habit, always washing your hands afterwards helps prevent the spread of illnesses. Special care after a wound incident is also appropriate.

Consider water sources that may not be potable. Bring water or utilize filters to remove potential contaminants, but also practice good food management in case of water ineffectiveness. Always practice routine personal responsibility best practices by not allowing inappropriate litter to accumulate, washing hands carefully after toileting, and disposing of hazardous waste appropriately. To protect their hands, those with cuts should consider using a glove. Educate others with whom you travel about appropriate hygiene techniques. Compliance can be a hardship for many if it is not a group commitment, and the mitigation of risk becomes less effective. Upper respiratory infections, gastrointestinal illnesses, and non-enteric illnesses are the most common illnesses that people experience when wilderness backpacking or hiking when first taking on a variety of outdoor-related activities. Implementing appropriate hygiene is an effective and essential component of preventing these diseases, and those who consistently uphold hygiene standards have statistically lower infection rates.

First Aid and Treatment of Wilderness Infections

First aid and treatment in the wilderness are guided by making a probable prediction for the event causing the patient's illness. Infections are a common cause of first aid use in the wilderness, and relying on standardized treatment guides can be less valuable. In many remote settings, getting help takes time, so giving treatment to relieve symptoms and delay further infection can be beneficial. Administering first aid once infected also increases the chance of minimal side effects and rapid recovery.

The most important first aid for the treatment of wilderness infections is to identify the symptoms as early as possible. When an infection is suspected, administer first aid immediately. Over-the-counter medications and oral rehydration solutions can also be used to alleviate the symptoms of infected individuals. But you must know when to secure medical assistance again. A few possible applications are offered, but the recommendations for the best treatment are always made by the healthcare professional once the patient has been examined. It is just a few days' hike to reach the nearest appropriate medical treatment centre. Infections are a common reason for outpatient visits, extending to 30 million per year. Wilderness settings expose individuals to a variety of unique pathogenic exposures and require personalized teaching and the creation of treatment algorithms to manage illness in austere environments.

In remote environments, wilderness infections can result from various exposure scenarios, including terrestrial pathogens in wounds, contaminated water supplies, insect bites, and zoonotic infections after handling wild game or exposure to commensal insects and rodents in cabins. In the following sections, we outline the etiologies, symptomatology, and management strategies of those infections likely to be encountered by healthcare providers working in medically austere environments. Specifically, it should be noted that basic procedures of wound care, infection prevention, monitoring of wounds for progression to skin and soft tissue infections, and oral rehydration therapy are the components of care relevant to multiple of these conditions. Furthermore, appropriate and timely treatment of these conditions can enhance clinical outcomes by reducing patient morbidity and, in the case of several envenomation conditions, save lives. Therefore, individuals working in medical settings remote from medical infrastructure will benefit from understanding initial healthcare provision for these infectious and toxic conditions. By addressing best practices in healthcare treatments away from medical facilities, we will improve the care of wilderness patients and help maximize their chances of a healthy return to civilization.