Wilderness-acquired diarrhea

Last updated
Wilderness-acquired diarrhea
Other nameswilderness diarrhea, or backcountry diarrhea

Wilderness-acquired diarrhea is a variety of traveler's diarrhea in which backpackers and other outdoor enthusiasts are affected. Potential sources are contaminated food or water, or "hand-to-mouth", directly from another person who is infected. [1] [2] Cases generally resolve spontaneously, with or without treatment, and the cause is typically unknown. The National Outdoor Leadership School has recorded about one incident per 5,000 person-field days by following strict protocols on hygiene and water treatment. [3] More limited, separate studies have presented highly varied estimated rates of affliction that range from 3 percent to 74 percent of wilderness visitors. [1] [4] One survey found that long-distance Appalachian Trail hikers reported diarrhea as their most common illness. [5] Based on reviews of epidemiologic data and literature, some researchers believe that the risks have been over-stated and are poorly understood by the public. [4] [6] [7] [8]

Contents

Symptoms and signs

The average incubation periods for giardiasis and cryptosporidiosis are each 7 days. [9] [10] Certain other bacterial and viral agents have shorter incubation periods, although hepatitis may take weeks to manifest itself. The onset usually occurs within the first week of return from the field, but may also occur at any time while hiking.[ citation needed ]

Most cases begin abruptly and usually result in increased frequency, volume, and weight of stool. Typically, a hiker experiences at least four to five loose or watery bowel movements each day. Other commonly associated symptoms are nausea, vomiting, abdominal cramping, bloating, low fever, urgency, and malaise, and usually the appetite is affected. The condition is much more serious if there is blood or mucus in stools, abdominal pain, or high fever. Dehydration is a possibility. Life-threatening illness resulting from WAD is extremely rare but can occur in people with weakened immune systems.[ citation needed ]

Some people may be carriers and not exhibit symptoms.[ citation needed ]

Causes

Infectious diarrhea acquired in the wilderness is caused by various bacteria, viruses, and parasites (protozoa). The most commonly reported are the protozoa Giardia and Cryptosporidium. [11] Other infectious agents may play a larger role than generally believed [4] and include Campylobacter , hepatitis A virus, hepatitis E virus, enterotoxogenic E. coli , E. coli O157:H7, Shigella , and various other viruses. More rarely, Yersinia enterocolitica , Aeromonas hydrophila , and Cyanobacterium may also cause disease. [12]

Giardia lamblia cysts usually do not tolerate freezing although some cysts can survive a single freeze–thaw cycle. [13] Cysts can remain viable for nearly three months in river water when the temperature is 10 °C and about one month at 15–20 °C in lake water. Cryptosporidium may survive in cold waters (4 °C) for up to 18 months, and can even withstand freezing, although its viability is thereby greatly reduced. [14] Many other varieties of diarrhea-causing organisms, including Shigella and Salmonella typhi , and hepatitis A virus, can survive freezing for weeks to months. [15] Virologists believe all surface water in the United States and Canada has the potential to contain human viruses, which cause a wide range of illnesses including diarrhea, polio and meningitis. [16] [17] [18] Modes of acquiring infection from these causes are limited to fecal-oral transmission, and contaminated water and food. The major factor governing pathogen content of surface water is human and animal activity in the watershed. [19]

Diagnosis

It may be difficult to associate a particular case of diarrhea with a recent wilderness trip of a few days because incubation of the disease may outlast the trip. Studies of trips [2] [20] that are much longer than the average incubation period, e.g. a week for Cryptosporidium and Giardia, [9] [10] are less susceptible to these errors since there is enough time for the diarrhea to occur during the trip. Other bacterial and viral agents have shorter incubation periods, although hepatitis may require weeks.[ citation needed ]

A suspected case of wilderness-acquired diarrhea may be assessed within the general context of intestinal complaints. During any given four-week period, as many as 7.2% of Americans may experience some form of infectious or non-infectious diarrhea. [21] There are an estimated 99 million annual cases of intestinal infectious disease in the United States, [22] most commonly from viruses, followed by bacteria and parasites, including Giardia and Cryptosporidium. There are an estimated 1.2 million U.S. cases of symptomatic giardiasis annually. [23] However, only about 40% of cases are symptomatic. [24]

Prevention

Since wilderness acquired diarrhea can be caused by insufficient hygiene, contaminated water, and (possibly) increased susceptibility from vitamin deficiency, prevention methods should address these causes.[ citation needed ]

Hygiene

The risk of fecal-oral transmission of pathogens that cause diarrhea can be significantly reduced by good hygiene, including washing hands with soap and water after urination and defecation, and washing eating utensils with warm soapy water. [2] Additionally a three-bowl system can be used for washing eating utensils. [1]

Treating water

Water can be treated in the wilderness through filtering, chemical disinfectants, a portable ultraviolet light device, pasteurizing or boiling. [25] [26] Factors in choice may include the number of people involved, space and weight considerations, the quality of available water, personal taste and preferences, and fuel availability.[ citation needed ]

In a study of long-distance backpacking, it was found that water filters were used more consistently than chemical disinfectants. Inconsistent use of iodine or chlorine may be due to disagreeable taste, extended treatment time or treatment complexity due to water temperature and turbidity. [20]

Because methods based on halogens, such as iodine and chlorine, do not kill Cryptosporidium, and because filtration misses some viruses, the best protection may require a two-step process of either filtration or coagulation-flocculation, followed by halogenation. Boiling is effective in all situations.[ citation needed ]

Iodine resins, if combined with microfiltration to remove resistant cysts, are also a viable single-step process, but may not be effective under all conditions. New one-step techniques using chlorine dioxide, ozone, and UV radiation may prove effective, but still require validation. [27]

Ultraviolet (UV) light for water disinfection is well established and widely used for large applications, like municipal water systems. Some hikers use small portable UV devices which meet the U.S. EPA Guide Standard and Protocol for Testing Microbiological Water Purifiers, for example, the SteriPEN. [28] [29] [30] Another approach to portable UV water purification is solar disinfection (also called sodis). Clear water is sterilized by putting it in a clear polyethylene (PET) bottle and leaving it in direct sunlight for 6 hours. [31]

Water risk avoidance

Different types of water sources may have different levels of contamination: [32]

  1. likely could have passed through an area subject to heavy human or animal use
  2. is cloudy, has surface foam, or has some other suspicious appearance.
  1. springs (provided the true source is not surface water a short distance above)
  2. large streams (those entering from the side may have less contamination than those paralleling the trail)
  3. fast-flowing streams
  4. higher elevations
  5. lakes with undisturbed sediments (10 days undisturbed water storage can result in 75–99% removal of coliform bacteria by settling to the bottom[ citation needed ])
  6. freshly melted snow
  7. deep wells (provided they aren't subject to contamination from surface runoff)
  8. regions where there was a heavy snow year when streams run full and long compared to dry years.

Rain storms can either improve or worsen water quality. They can wash contaminants into water and stir up contaminated sediments with increasing flow, but can also dilute contaminants by adding large amounts of water. [32]

Unfortunately, there have not been any epidemiological studies to validate the above, except possibly for the case of spring water. [2]

Vitamins

One study suggests that on very long trips in the wilderness, taking multivitamins may reduce the incidence of diarrhea. [2]

Treatment

WAD is typically self-limited, generally resolving without specific treatment. Oral rehydration therapy with rehydration salts is often beneficial to replace lost fluids and electrolytes. Clear, disinfected water or other liquids are routinely recommended.[ citation needed ]

Hikers who develop three or more loose stools in a 24-hour period – especially if associated with nausea, vomiting, abdominal cramps, fever, or blood in stools  – should be treated by a doctor and may benefit from antibiotics, usually given for 3–5 days. Alternatively, a single dose azithromycin or levofloxacin may be prescribed. [33] If diarrhea persists despite therapy, travelers should be evaluated and treated for possible parasitic infection.[ citation needed ]

Cryptosporidium can be quite dangerous to patients with compromised immune systems. Alinia (nitazoxanide) is approved by the FDA for treatment of Cryptosporidium.

Epidemiology

The risk of acquiring infectious diarrhea in the wilderness arises from inadvertent ingestion of pathogens. Various studies have sought to estimate diarrhea attack rates among wilderness travelers, and results have ranged widely. The variation of diarrhea rate between studies may depend on the time of year, the location of the study, the length of time the hikers were in the wilderness, [2] [34] the prevention methods used, and the study methodology.

The National Outdoor Leadership School (NOLS), which emphasizes strict hand-washing techniques, water disinfection and washing of common cooking utensils in their programs, reports that gastrointestinal illnesses occurred at a rate of only 0.26 per 1000 program days. [35] In contrast, a survey of long-distance Appalachian Trail hikers found more than half the respondents reported at least one episode of diarrhea that lasted an average of two days. (Infectious diarrhea may last longer than an average of two days; certain forms of non-infectious diarrhea, caused by diet change etc., can be of very brief duration). Analysis of this survey found occurrence of diarrhea was positively associated with the duration of exposure in the wilderness. During any given four-week period, as many as 7.2% of Americans may experience some form of infectious or non-infectious diarrhea. [21] A number of behaviors each individually reduced the incidence of diarrhea: treating water; routinely washing hands with soap and water after defecation and urination; cleaning cooking utensils with soap and warm water; and taking multi-vitamins. [2] [20]

A variety of pathogens can cause infectious diarrhea, and most cases among backpackers appear to be caused by bacteria from feces. A study at Grand Teton National Park found 69% of diarrhea affected visitors had no identifiable cause, that 23% had diarrhea due to Campylobacter and 8% of patients with diarrhea had giardiasis. Campylobacter enteritis occurred most frequently in young adults who had hiked in wilderness areas and drunk untreated surface water in the week prior. [36] Another study tested 35 individuals before and after a trip to the Desolation Wilderness of California. Giardia cysts were found in fecal samples from two people after the trip, but they were asymptomatic. A third person was empirically treated for symptoms of giardiasis. [37]

Fecal-oral transmission may be the most common vector for wilderness acquired diarrhea. There are differing opinions regarding the importance of routine disinfection of water during relatively brief backcountry visits. [6] [4] [7]

Backcountry water quality surveys

Infection by fecal coliform bacteria, which indicate fecal pollution, are more common than giardiasis. [38] Risks are highest in surface water near trails used by pack animals and cattle pastures. [39] [40]

Most samples of backcountry water in the Desolation Wilderness in California have found very low or no Giardia cysts. [37] The infectious dose of giardia, however, is very low, with about 2% chance of infection from a single cyst. [41] Also, very few studies have addressed the issue of transient contamination. According to one researcher, the likely model for the risk of Giardia from wilderness water is pulse contamination, that is, a brief period of high cyst concentration from fecal contamination. [7] [42]

Terminology

Diarrhea acquired in the wilderness or other remote areas is typically a form of infectious diarrhea, itself classified as a type of secretory diarrhea. These are all considered forms of gastroenteritis. The term may be applied in various remote areas of non-tropical developed countries (U.S., Canada, western Europe, etc.), but is less applicable in developing countries, and in the tropics, because of the different pathogens that are most likely to cause infection. [7]

See also

Footnotes

  1. 1 2 3 Hargreaves JS (2006). "Laboratory evaluation of the 3-bowl system used for washing-up eating utensils in the field". Wilderness Environ Med. 17 (2): 94–102. doi: 10.1580/PR17-05.1 . PMID   16805145. Diarrhea is a common illness of wilderness travelers, occurring in about one third of expedition participants and participants on wilderness recreation courses. The incidence of diarrhea may be as high as 74% on adventure trips. ...Wilderness diarrhea is not caused solely by waterborne pathogens, ... poor hygiene, with fecal-oral transmission, is also a contributing factor
  2. 1 2 3 4 5 6 7 Boulware DR (2004). "Influence of Hygiene on Gastrointestinal Illness Among Wilderness Backpackers". J Travel Med. 11 (1): 27–33. doi: 10.2310/7060.2004.13621 . PMID   14769284.
  3. ↑ McIntosh SE, Leemon D, Visitacion J, Schimelpfenig T, Fosnocht D (2007). "Medical Incidents and Evacuations on Wilderness Expeditions" (PDF). Wilderness and Environmental Medicine. 18 (4): 298–304. doi:10.1580/07-WEME-OR-093R1.1. PMID   18076301. S2CID   1401977.[ permanent dead link ]
  4. 1 2 3 4 Zell SC (1992). "Epidemiology of Wilderness-acquired Diarrhea: Implications for Prevention and Treatment". J Wilderness Med. 3 (3): 241–9. doi:10.1580/0953-9859-3.3.241. S2CID   73001096.
  5. ↑ Boulware DR, Forgey WW, Martin WJ (March 2003). "Medical risks of wilderness hiking". The American Journal of Medicine. 114 (4): 288–93. doi:10.1016/S0002-9343(02)01494-8. PMID   12681456.
  6. 1 2 Welch TP (2000). "Risk of giardiasis from consumption of wilderness water in North America: a systematic review of epidemiologic data". International Journal of Infectious Diseases. 4 (2): 100–3. doi: 10.1016/S1201-9712(00)90102-4 . PMID   10737847. Archived version April 20, 2010
  7. 1 2 3 4 Backer, Howard (1992). "Wilderness acquired diarrhea (editorial)". Journal of Wilderness Medicine. 3: 237–240. doi:10.1580/0953-9859-3.3.237. S2CID   71955543.
  8. ↑ Derlet, Robert W. (April 2004). "High Sierra Water: What is in the H2O?". Yosemite Association. Archived from the original on 2007-10-12.
  9. 1 2 CDC Division of Parasitic Diseases (2004). "CDC Fact sheet: Giardiasis". Centers for Disease Control. Retrieved 2008-10-13.
  10. 1 2 National Center for Zoonotic, Vector-Borne, and Enteric Diseases (2008-04-16). ""Crypto" - Cryptosporiodosis". Centers for Disease Control. Retrieved 2008-10-13.{{cite web}}: CS1 maint: multiple names: authors list (link)
  11. ↑ Backer 2007 , p. 1371
  12. ↑ Backer 2007 , p. 1369
  13. ↑ EPA, OEI, OIAA, IAD, US (8 November 2016). "Water Resources" (PDF).{{cite web}}: CS1 maint: multiple names: authors list (link)
  14. ↑ Prepared by Federal-Provincial-Territorial Committee on Drinking Water of the Federal-Provincial-Territorial Committee on Health and the Environment (2004) (2004). "Protozoa: Giardia and Cryptosporidium" (PDF). Guidelines for Canadian Drinking Water Quality: Supporting Documentation. Health Canada. Retrieved 2008-08-07.
  15. ↑ Dickens DL, DuPont HL, Johnson PC (June 1985). "Survival of bacterial enteropathogens in the ice of popular drinks". JAMA. 253 (21): 3141–3. doi:10.1001/jama.253.21.3141. PMID   3889393.
  16. ↑ Backer H (2000). "In search of the perfect water treatment method" (PDF). Wilderness Environ Med. 11 (1): 1–4. doi: 10.1580/1080-6032(2000)011[0001:isotpw]2.3.co;2 . PMID   10731899.
  17. ↑ Gerba C, Rose J (1990). "Viruses in Source and Drinking Water". In McFeters, Gordon A. (ed.). Drinking water microbiology: progress and recent developments. Berlin: Springer-Verlag. pp. 380–99. ISBN   0-387-97162-9.
  18. ↑ White, George W. (1992). The handbook of chlorination and alternative disinfectants (3rd ed.). New York: Van Nostrand Reinhold. ISBN   0-442-00693-4.
  19. ↑ Backer 2007 , p. 1374
  20. 1 2 3 Boulware DR, Forgey WW, Martin WJ 2nd (2003). "Medical Risks of Wilderness Hiking". Am J Med. 114 (4): 288–93. doi:10.1016/S0002-9343(02)01494-8. PMID   12681456.
  21. 1 2 Scallan, E. J.; A. Banerjee; S. E. Majowicz; et al. (2002). "Prevalence of Diarrhea in the Community in Australia, Canada, Ireland and the United States" (PDF). CDC. Retrieved 2008-10-15.
  22. ↑ Garthright WE, Archer DL, Kvenberg JE (1988). "Estimates of incidence and costs of intestinal infectious diseases in the United States". Public Health Rep. 103 (2): 107–15. PMC   1477958 . PMID   3128825.
  23. ↑ "Giardiasis Surveillance — United States, 2009–2010". www.cdc.gov.
  24. ↑ Howard Backer (1992). "Wilderness acquired diarrhea". Journal of Wilderness Medicine. 3 (3): 237–240. doi:10.1580/0953-9859-3.3.237. S2CID   71955543.
  25. ↑ Backer 2007 , pp. 1368–417
  26. ↑ Johnson, Mark (2003). The Ultimate Desert Handbook : A Manual for Desert Hikers, Campers and Travelers. International Marine/Ragged Mountain Press. p. 46. ISBN   0-07-139303-X.
  27. ↑ Backer H (February 2002). "Water disinfection for international and wilderness travelers". Clin. Infect. Dis. 34 (3): 355–64. doi: 10.1086/324747 . PMID   11774083.
  28. ↑ Backer 2007, p. 1411
  29. ↑ "Steripen - Proven Technology". Hydro-Photon, Inc. 2008. Retrieved 2008-10-14.
  30. ↑ "Steripen - Microbiological Testing". Hydro-Photon, Inc. 2008. Retrieved 2008-10-14.
  31. ↑ "Household Water Treatment Options in Developing Countries: Solar Disinfection (SODIS)" (PDF). Centers for Disease Control and Prevention (CDC). January 2008. Retrieved 2010-07-31.
  32. 1 2 Backer 2007 , pp. 1373–4
  33. ↑ Sanders JW, Frenck RW, Putnam SD, et al. (August 2007). "Azithromycin and loperamide are comparable to levofloxacin and loperamide for the treatment of traveler's diarrhea in United States military personnel in Turkey". Clin. Infect. Dis. 45 (3): 294–301. doi: 10.1086/519264 . PMID   18688944.
  34. ↑ Gardner TB, Hill DR (2002). "Illness and injury among long-distance hikers on the Long Trail, Vermont". Wilderness & Environmental Medicine. 13 (2): 131–4. doi: 10.1580/1080-6032(2002)013[0131:iaiald]2.0.co;2 . PMID   12092966.
  35. ↑ McIntosh, Scott E.; Drew Leemon; Joshua Visitacion; et al. (2007). "Medical incidents and evacuations on wilderness expeditions" (PDF). Wilderness and Environmental Medicine. 18 (4): 298–304. doi:10.1580/07-WEME-OR-093R1.1. PMID   18076301. S2CID   1401977.
  36. ↑ Taylor, D. N.; K. T. McDermott; J. R. Little; et al. (1983). "Campylobacter enteritis from untreated water in the Rocky Mountains". Ann Intern Med. 99 (1): 38–40. doi:10.7326/0003-4819-99-1-38. PMID   6859722 . Retrieved 2008-10-16.
  37. 1 2 Zell SC, Sorenson SK (1993). "Cyst acquisition rate for Giardia lamblia in backcountry travelers to Desolation Wilderness, Lake Tahoe" (PDF). Journal of Wilderness Medicine. 4 (2): 147–54. doi:10.1580/0953-9859-4.2.147.
  38. ↑ Derlet, Robert W.; James Carlson (2003). "Sierra Nevada Water: Is it safe to drink? - Analysis of Yosemite National Park Wilderness water for Coliform and Pathologic Bacteria". SierraNevadaWild.gov. Sierra Wilderness Education Project. Archived from the original on May 13, 2008. Retrieved 2008-10-15.
  39. ↑ Derlet RW (2008). "Backpacking in Yosemite and Kings Canyon National Parks and neighboring wilderness areas: how safe is the water to drink?". Journal of Travel Medicine. 15 (4): 209–15. doi: 10.1111/j.1708-8305.2008.00201.x . PMID   18666919.
  40. ↑ Derlet, Robert W. (April 2004). "High Sierra Water: What is in the H2O?". Yosemite Association.
  41. ↑ Rose JB, Haas CN, Regli S (1991). "Risk assessment and control of waterborne giardiasis". Am J Public Health. 81 (6): 709–13. doi:10.2105/ajph.81.6.709. PMC   1405147 . PMID   2029038.
  42. ↑ Backer 2007 , p. 1372

Related Research Articles

<span class="mw-page-title-main">Diarrhea</span> Loose or liquid bowel movements

Diarrhea, also spelled diarrhoea or diarrhœa in British English, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin with loss of the normal stretchiness of the skin and irritable behaviour. This can progress to decreased urination, loss of skin color, a fast heart rate, and a decrease in responsiveness as it becomes more severe. Loose but non-watery stools in babies who are exclusively breastfed, however, are normal.

<i>Giardia</i> Genus of flagellate intestinal eukayotes parasitic in various vertebrate

Giardia is a genus of anaerobic flagellated protozoan parasites of the phylum Metamonada that colonise and reproduce in the small intestines of several vertebrates, causing the disease giardiasis. Their life cycle alternates between a swimming trophozoite and an infective, resistant cyst. Giardia were first described by the Dutch microscopist Antonie van Leeuwenhoek in 1681. The genus is named after French zoologist Alfred Mathieu Giard.

<span class="mw-page-title-main">Drinking water</span> Water safe for consumption

Drinking water or potable water is water that is safe for ingestion, either when drunk directly in liquid form or consumed indirectly through food preparation. It is often supplied through taps in which case it is also called tap water. Typically in developed countries, tap water meets drinking water quality standards, even though only a small proportion is actually consumed or used in food preparation. Other typical uses for tap water include washing, toilets, and irrigation. Greywater may also be used for toilets or irrigation. Its use for irrigation however may be associated with risks.

<i>Giardia duodenalis</i> Parasitic microorganism that causes giardiasis

Giardia duodenalis, also known as Giardia intestinalis and Giardia lamblia, is a flagellated parasitic microorganism of the genus Giardia that colonizes the small intestine, causing a diarrheal condition known as giardiasis. The parasite attaches to the epithelium by a ventral adhesive disc or sucker, and reproduces via binary fission. Giardiasis does not spread via the bloodstream, nor does it spread to other parts of the gastrointestinal tract, but remains confined to the lumen of the small intestine. Giardia has an outer membrane that makes it possible to retain life, even when outside of the host body, and which can make it tolerant to chlorine disinfection. Giardia trophozoites absorb their nutrients from the lumen, and are anaerobes. If the organism is split and stained, its characteristic pattern resembles the familiar "smiley face" symbol.

<span class="mw-page-title-main">Cryptosporidiosis</span> Parasitic disease

Cryptosporidiosis, sometimes informally called crypto, is a parasitic disease caused by Cryptosporidium, a genus of protozoan parasites in the phylum Apicomplexa. It affects the distal small intestine and can affect the respiratory tract in both immunocompetent and immunocompromised individuals, resulting in watery diarrhea with or without an unexplained cough. In immunosuppressed individuals, the symptoms are particularly severe and can be fatal. It is primarily spread through the fecal-oral route, often through contaminated water; recent evidence suggests that it can also be transmitted via fomites contaminated with respiratory secretions.

<span class="mw-page-title-main">Giardiasis</span> Parasitic disease that results in diarrhea

Giardiasis is a parasitic disease caused by Giardia duodenalis. Infected individuals who experience symptoms may have diarrhoea, abdominal pain, and weight loss. Less common symptoms include vomiting and blood in the stool. Symptoms usually begin one to three weeks after exposure and, without treatment, may last two to six weeks or longer.

<span class="mw-page-title-main">Fecal–oral route</span> Disease transmission via pathogens from fecal particles

The fecal–oral route describes a particular route of transmission of a disease wherein pathogens in fecal particles pass from one person to the mouth of another person. Main causes of fecal–oral disease transmission include lack of adequate sanitation, and poor hygiene practices. If soil or water bodies are polluted with fecal material, humans can be infected with waterborne diseases or soil-transmitted diseases. Fecal contamination of food is another form of fecal-oral transmission. Washing hands properly after changing a baby's diaper or after performing anal hygiene can prevent foodborne illness from spreading.

<span class="mw-page-title-main">Gastroenteritis</span> Inflammation of the stomach and small intestine

Gastroenteritis, also known as infectious diarrhea or simply as gastro, is an inflammation of the gastrointestinal tract including the stomach and intestine. Symptoms may include diarrhea, vomiting, and abdominal pain. Fever, lack of energy, and dehydration may also occur. This typically lasts less than two weeks. Although it is not related to influenza, in the U.S. it is sometimes called the "stomach flu".

<span class="mw-page-title-main">Travelers' diarrhea</span> Stomach and intestinal infection

Travelers' diarrhea (TD) is a stomach and intestinal infection. TD is defined as the passage of unformed stool while traveling. It may be accompanied by abdominal cramps, nausea, fever, headache and bloating. Occasionally bloody diarrhea may occur. Most travelers recover within three to four days with little or no treatment. About 12% of people may have symptoms for a week.

<i>Cryptosporidium parvum</i> Species of single-celled organism

Cryptosporidium parvum is one of several species that cause cryptosporidiosis, a parasitic disease of the mammalian intestinal tract.

<i>Cryptosporidium</i> Genus of single-celled organisms

Cryptosporidium, sometimes called crypto, is an apicomplexan genus of alveolates which are parasites that can cause a respiratory and gastrointestinal illness (cryptosporidiosis) that primarily involves watery diarrhea, sometimes with a persistent cough.

<i>Cyclospora cayetanensis</i> Species of single-celled organism

Cyclospora cayetanensis is a coccidian parasite that causes a diarrheal disease called cyclosporiasis in humans and possibly in other primates. Originally reported as a novel pathogen of probable coccidian nature in the 1980s and described in the early 1990s, it was virtually unknown in developed countries until awareness increased due to several outbreaks linked with fecally contaminated imported produce. C. cayetanensis has since emerged as an endemic cause of diarrheal disease in tropical countries and a cause of traveler's diarrhea and food-borne infections in developed nations. This species was placed in the genus Cyclospora because of the spherical shape of its sporocysts. The specific name refers to the Cayetano Heredia University in Lima, Peru, where early epidemiological and taxonomic work was done.

<span class="mw-page-title-main">Hand sanitizer</span> Alternative to hand washing

Hand sanitizer is a liquid, gel or foam generally used to kill many viruses/bacteria/microorganisms on the hands. In most settings, hand washing with soap and water is generally preferred. Hand sanitizer is less effective at killing certain kinds of germs, such as norovirus and Clostridium difficile, and unlike hand washing, it cannot physically remove harmful chemicals. People may incorrectly wipe off hand sanitizer before it has dried, and some are less effective because their alcohol concentrations are too low.

<span class="mw-page-title-main">Portable water purification</span> Self-contained, easily transported units used to purify water from untreated sources

Portable water purification devices are self-contained, easily transported units used to purify water from untreated sources for drinking purposes. Their main function is to eliminate pathogens, and often also of suspended solids and some unpalatable or toxic compounds.

The discovery of disease-causing pathogens is an important activity in the field of medical science. Many viruses, bacteria, protozoa, fungi, helminthes and prions are identified as a confirmed or potential pathogen. In the United States, a Centers for Disease Control program, begun in 1995, identified over a hundred patients with life-threatening illnesses that were considered to be of an infectious cause, but that could not be linked to a known pathogen. The association of pathogens with disease can be a complex and controversial process, in some cases requiring decades or even centuries to achieve.

<span class="mw-page-title-main">Human feces</span> Metabolic waste of the human digestive system

Human feces is the solid or semisolid remains of food that could not be digested or absorbed in the small intestine of humans, but has been further broken down by bacteria in the large intestine. It also contains bacteria and a relatively small amount of metabolic waste products such as bacterially altered bilirubin, and the dead epithelial cells from the lining of the gut. It is discharged through the anus during a process called defecation.

<span class="mw-page-title-main">Protozoan infection</span> Parasitic disease caused by a protozoan

Protozoan infections are parasitic diseases caused by organisms formerly classified in the kingdom Protozoa. They are usually contracted by either an insect vector or by contact with an infected substance or surface and include organisms that are now classified in the supergroups Excavata, Amoebozoa, SAR, and Archaeplastida.

Una M. Ryan is a biochemist from Ireland, researching parasites and infectious agents in Australia, where she lives. She is an associate professor at the School of Veterinary and Biomedical Sciences of Murdoch University. In 2000, she received the Frank Fenner Prize for Life Scientist of the Year from the Prime Minister of Australia for her work in isolating a method of diagnosing parasites.

Diving equipment may be exposed to contamination in use and when this happens it must be decontaminated. This is a particular issue for hazmat diving, but incidental contamination can occur in other environments. Personal diving equipment shared by more than one user requires disinfection before use. Shared use is common for expensive commercial diving equipment, and for rental recreational equipment, and some items such as demand valves, masks, helmets and snorkels which are worn over the face or held in the mouth are possible vectors for infection by a variety of pathogens. Diving suits are also likely to be contaminated, but less likely to transmit infection directly.

Herbert "Bert" Lancashire DuPont is an American physician, medical school professor, and medical researcher, specializing in infectious diseases.

References

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.