Most field workers prepare for the macro-biological hazards in the field, but knowledge of the microbiological hazards in the field may be just as important to your health. The tables below list some of the known microbiological hazards in Western Canada and some that are spreading from south of the border. Early recognition of the symptoms of infections from water-borne or arthropod-borne infections could save you from life-threatening illnesses or chronic conditions.
One of the best ways to be prepared for the microbiological hazards is knowing how the bacteria, protozoa, spores, or virus is transmitted and take the appropriate precautions to avoid being contaminated. Once you know the routes of entry for a particular parasite – adopt practices to avoid infections.
Consider the routes of entry:
1. Oral Routes: eg. contamination on hands from soil or rocks:
- wear gloves to avoid contamination.
- wear overalls, eye protection or particle masks.
- do not place your hand near face – no eating, drinking, smoking, chewing gum until you have washed your hands with soap and water.
Another Oral Route is ingesting contaminated food or water:
- cook food well and wash all vegetables in filtered, chemically treated or boiled water.
- do not drink lake or stream waters until the water has been filtered, chemically treated or boiled.
- food must be stored properly while working in the field.
2. Respiratory Routes: Some bacteria or viruses enter the body through inhalation: – eg. Hanta Virus, rabbit fever
- avoid dusts that may be contaminated.
- wear an N95 repirator with Hepa filters. Respirator fit tests are required before heading out into the field.
- disinfect area – find out what you need to use to disinfect the area and know the procedure for disinfection.
3. Open Skin Route: Cuts and abrasions or direct bites: eg. West Nile Virus, Rabies, rabbit fever, tetanus
- wear protective clothing (gloves, boots, coveralls).
- protect exposed skin – insect repellent.
- don’t touch wildlife; dead or alive.
Consider immunization for things like tetanus or other diseases if you are engaged in activities that put you at greater risk. Routes of Transmission
Tick Prevention:
The following web-link discusses how you should dress to avoid ticks on the grasses and brush in the areas you are working in. It also shows how to remove a tick if you have been bitten. The prompt removal of ticks can help you to avoid many of the tick borne illnesses listed in the tables below. Always save any tick you have removed in a 70% alcohol solution for later identification.
Check out Alberta’s Lyme Disease and Tick Surveillance Program site: Tick prevention in Alberta
Please view the video of how to remove ticks safely: How to properly remove a Tick
Since some ticks can transmit serious diseases, people should be aware of the symptoms of tick-bourne illnesses. Many tick-bourne illnesses present with similar signs and symptoms and knowing the differences between the various disease’s symptoms will affect the course of treatment. Symptoms of Tickbourne Illnesses.
Tick Identification:
Below are some sites that will help you to identify the most common North American ticks. It is important to keep the tick if you find you have received a tick bite. The type of tick will help aid in the identification of the illness.
Tick Identification and How to Repel Ticks and Mosquitoes
Canadian Lyme Disease Foundation
Mosquito Prevention:
West Nile Virus has spread all across North America, it is important to take steps to avoid being bitten by mosquitoes. There are many sites for information on this topic and staying informed is the best way to prevent catching this disease.
The following information may be useful in helping you avoid being bitten by mosquitoes while working in the field:
Another link of interest is this one which describes several serious arthropod-borne viruses that are emerging in North America: http://www.cdc.gov/ncidod/dvbid/arbor/arbdet.htm
Water Borne Diseases:
It is never wise to drink water from rivers and streams, no matter how clear and clean the water appears. When you are working in the field you need to consider your access to clean water. If there is nothing available you will have to take steps to protect yourself by using a method of water purification. When camping or working in an area of questionable water quality, your drinking water should be boiled for at least 10 to 12 minutes. You can remove many contaminants except bacteria without boiling by using water filters. Always follow manufacturer’s directions and purchase a good quality filter unit to take into the field with you. Know how to use the filter before you leave and purchase additional filter units to have enough on hand.
Another alternative is to have bottled water available at your camp. However, this may not be an option for some remote areas you will be working in.
Other methods for cleaning water include water purification methods such as iodine or chlorine tablets, two methods used to kill water-borne pathogens. The choice of water treatment will depend upon your source of drinking water and the amount you will need.
The following web-link describes how to treat water to ensure it is safe to drink: http://wwwn.cdc.gov/travel/contentWaterTreatment.aspx
Hazards in Western Canada Regions
| Name: | Lockjaw, tetanus (bacterium) |
| Agent: | Clostridium tetani |
| Host: | Humans, animals (including farm animals) – in feces |
| Mode of Infection: | Spores enter through wounds, (cuts or abrasions) via soil or animal feces contamination; common in agricultural areas |
| Incubation Period: | ~ 10 days |
| Symptoms: | Endotoxins causes severe muscle contractions of neck and trunk; can be fatal |
| Treatment: | Antibiotics |
| Immunization: | Available – usually mixed along with diptheria immunizations; should be obtained every 10 years. |
| Further information: | US Centre of Disease Control |
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| Name: | Cryptosporidiosis (protazoan) or “Crypto” |
| Agent: | Cryptosporidium parvun |
| Host:; | Humans, poultry, fish, reptiles, mammals (small/large) in feces. |
| Mode of Infection: | Ingestion; fecal-oral route, animal to person, food and waterborne. |
| Incubation period: | ~ 7 days |
| Symptoms: | Diarrhea, abdominal cramps, vomiting |
| Treatment: | none |
| Immunization: | None, refer to further information on how to avoid |
| Further information: | http://www.cdc.gov/crypto/ |
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| Name: | Beaver Fever, Giardia (protazoan) |
| Agent: | Giardia lamblia |
| Host: | Humans and animals (wild and domestic) |
| Mode of Infection: | Ingestion: fecal – oral, on hands or via contaminated water |
| Incubation period: | ~ 1 to 2 weeks |
| Symptoms: | None and then sudden diarrhea, cramps and fatigue |
| Treatment: | Drugs are available |
| Immunization: | No |
| Further information: | US Centre of Disease Control |
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| Name: | Listeriosis, listerella (bacterium) |
| Agent: | Listeria monocytogeneis |
| Host: | Humans, domestic and wild mammals, fowl; via feces or during pregnancy/birth |
| Mode of Infection: | Ingestion (vegetables, dairy), contact with feces or contaminated soil, handling fetuses possibly inhalation. |
| Incubation period: | ~ 7 days |
| Symptoms: | Fever, muscle aches, and sometimes gastrintestinal symptoms such as nausea or diarrhea |
| Treatment: | Antibiotics |
| Immunization: | No |
| Further information: | http://www.cdc.gov/listeria/index.html |
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| Name: | Toxoplasmosis (protazoan) |
| Agent: | Toxoplasma gondii |
| Host: | Cats, other domestic and wild animals, humans |
| Mode of Infection: | Ingestion of undercooked meat, contaminated milk/food/water, soil contaminated with feces, inhalation of cysts. |
| Incubation period: | ~ 15 days |
| Symptoms: | Often none; fever, sore throat, rash; similar to mononucleosis |
| Treatment: | Drugs |
| Immunization: | No |
| Further information: | http://www.cdc.gov/toxoplasmosis/ |
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| Name: | Trichnellosis, Trichinosis (roundworms) |
| Agent: | Trichinella spiraleis, T. psuedospiraleis, T. nativa, T. nelsoni, T. britovi |
| Host:; | Humans, domestic and wild animals, marine mammals |
| Mode of Infection: | Ingestion of larvae, especially in undercooked pork and wild meats |
| Incubation period: | Abdominal symptoms in 2 days, 2 – 8 weeks for systemic reactions |
| Symptoms: | Gastrointestinal symptoms, then muscle soreness/pain; swelling of the upper eyelid, cardiac/neurologic complications; death |
| Treatment: | Drugs |
| Immunization: | None |
| Further information: | http://www.cdc.gov/ncidod/dpd/parasites/trichinosis/default.htm |
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| Name: | Tapeworms (Avedar Hydatid Disease or AHD) |
| Agent: | Echinococcus multilocularis, E. granulosus. |
| Host: | Foxes, wolves, coyotes, dogs, cats and herbivores like voles, lemmings, shrews, mice, sheep, moose |
| Mode of Infection: | Ingestion of eggs from fecal contamination of water, food. |
| Incubation period: | Cysts grow over years, |
| Symptoms: | Symptoms depend on where the cyst grows; blindness, seizures, bone breakage. |
| Treatment: | Surgery &Drugs |
| Immunization: | See information at: |
| Further information: | |
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| Name: | Toxocariasis or Roundworm Infection |
| Agent: | Toxocara canis, Toxocara cati |
| Host: | Humans, cats, dogs; in feces |
| Mode of Infection: | Ingestion: eggs from contaminated soil or unwashed vegetables |
| Incubation period: | Weeks to months |
| Symptoms: | Often none but can be severe. OLM – Ocular larva migrans can lead to blindness, VLM – Visceral larva migrans is the swelling of organs or nervous system. Symptoms of VLM are fever, coughing, asthma or pneumonia. |
| Treatment: | Drugs available if infected; have dogs & cats treated regularly for worms |
| Immunization: | None, see information |
| Further information: | http://www.cdc.gov/ncidod/dpd/parasites/toxocara/default.htm |
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| Name: | Rabies, hydrophobia |
| Agent: | Rabies virus (Rhabdoviridae family) |
| Host: | Wild animals such as racoons, skunks, coyotes, wolves, fox, bats, cats and dogs |
| Mode of Infection: | Virus in salivia is transmitted via bites, less often: if saliva gets directly into the eyes, nose, mouth, or a wound. |
| Incubation period: | ~ 4 weeks |
| Symptoms: | Apprehension, headaches, fever, delirium, spasms, paralysis, death |
| Treatment: | Wash wound immediately and treat with 70% alcohol. Always seek medical treatment if you are bitten by a wild animal. Quarantine any domestic animal if it has bitten you in order to watch for signs of rabies. |
| Immunization: | Available for occupational risk group, series takes 1 month. |
| Further information: | |
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| Name: | Hanta Virus |
| Agent: | Deer Mouse = Sin Nombre Virus (SNV) |
| Host: | Canada & US: Deer Mouse, Southeast US: Cotton Rat |
| Mode of Infection: | Exposure to an infected rodent’s salavia, urine, droppings or nesting materials. Virus can live for up to a week on dried droppings of mouse. |
| Incubation period: | 1 to 3 weeks and sometimes up to 6 weeks |
| Symptoms: | Fever, headaches, severe muscle aches, possible stomach aches, possible dizziness or chills. 4-5 days later shortness of breath, death. 50% death rate despite medical treatment. |
| Treatment: | Supportive drugs – must seek medical attention |
| Immunization: | None |
| Further information: | |
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| Name: | West Nile Virus (WNV) |
| Agent: | Flavivirus |
| Host: | Mosquitoes, birds (over 110 species of birds are known to have been infected with WNV), horses, humans and other domestic animals. |
| Mode of Infection: | Bite of an infected mosquito. |
| Incubation period: | 3 -12 days |
| Symptoms: | Possible no symptoms, some have fever, headaches, stiff muscles (all can range from mild to severe), can progress to encephalitis or meningitis. Can be fatal. |
| Treatment: | Treat symptoms and complications of encephalitis or meningitis. |
| Immunization: | None |
| Further information: | |
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| Name: | Tularemia, Rabbit Fever, Deer Fly Fever |
| Agent: | Bacterium: Francisella tularensis |
| Host: | Rabbits, Hares and rodents – widespread in North America |
| Mode of Infection: | Infection to humans is caused by bites of arthropods, commonly ticks and deerflies, or by handling infected animal carcasses or by eating or drinking infected food or water. Bacterium can live in soil or water for weeks. |
| Incubation period: | 3 to 5 days |
| Symptoms: | Early onset of fever, chills, headaches, muscle aches, fatigue, joint pain and a dry cough. Can develop into pneumonia. Can be fatal if left untreated. |
| Treatment: | 10-14 days antibiotics |
| Immunization: | Vaccine available for laboratory workers. Vaccine is under review. |
| Further information: | |
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| Name: | Rocky Mountain Spotted Fever |
| Agent: | Bacterium: Rickettsia rickettsii |
| Host: | Hard ticks such as: Dog Tick, Wood Tick and Lone Star Tick. Located throughout US and southern Canada, Central America, Mexico and parts of South America |
| Mode of Infection: | Bitten by an infected tick |
| Incubation period: | 5 to 10 days |
| Symptoms: | Sudden onset of fever, headache & muscle pain followed by a rash. Without treatment can be fatal. With early antibiotic treatment 3-5% cases are still fatal. |
| Treatment: | Treatment with antibiotics early in infection will reduce fatality rate. Remove ticks carefully and keep for identification |
| Immunization: | Vaccine not available – limit exposure to ticks, if bitten – remove tick carefully and keep tick for identification. |
| Further information: | |
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| Name: | Colorado Spotted Fever (sometimes called the Saddleback Fever) |
| Agent: | RNA Virus: Arbovirus |
| Host: | Wood Tick (Dermacentor andersoni) Located in Western US, British Columbia and Alberta. |
| Mode of Infection: | Bitten by an infected tick. |
| Incubation period: | 3 – 6 days |
| Symptoms: | Fever for 2 to 3 days, then abates and recurs 1-3 days later for another few days. Headache, fatigue, eye pain & sensitivity to light. Some will develop a rash and some will have stiff neck. |
| Treatment: | Bedrest. Seek medical attention to rule out other tick borne diseases. Remove ticks carefully and keep for identification |
| Immunization: | None |
| Further information: | |
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| Name: | Lyme Disease |
| Agent: | Western Black-legged Tick and Deer tick can carry the bacteria (Ixodes damminie, or Borrelia burgdorferi) |
| Host: | Rodents, deer, rabbits, squirrels, birds. Located throughout the US, British Columbia, southern & eastern Ontario, southeast Quebec, southeastern Manitoba and parts of New Brunswick and Nova Scotia. Sporatically in other provinces. |
| Mode of Infection: | Bitten by an infected tick. |
| Incubation period: | 3 to 30 days |
| Symptoms: | Can appear as a ring-like rash around the tick bite, flu-like symptoms with fever, chills, aching joints and muscles, fatigue and swollen glands. As Lyme Disease progresses it can cause more serious symptoms such as neurological and muscular problems in some people. Mimics other diseases and can be difficult to diagnose. |
| Treatment: | Antibiotics – attempt to treat in early stages. Remove tick and keep for identification. Later stages are more difficult to treat. |
| Immunization: | Vaccine is available |
| Further information: | |
| Name: | Relapsing Fever |
| Agent: | Bacterial: Several species of Borrelia spirochete |
| Host: | Body lice in Asia, Africa & Europe or by soft body ticks in the Americas |
| Mode of Infection: | Bite of an infected tick |
| Incubation period: | 3 to 11 days |
| Symptoms: | Chills, head ache, muscle pain and sometimes vomiting. Rash may appear. Fever remains high for 3 to 5 days, then disappears. After 1 – 2 weeks a milder relapse begins & jaundice is common with relapse. The illness will clear again – person can have 2 to 10 relapses at one to two week intervals. |
| Treatment: | Antibiotics |
| Immunization: | None |
| Further information: |
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| Name: | Tick Paralysis |
| Agent: | Neurotoxins present in five species of North American ticks |
| Host: | Engorged pregnant ticks: Rocky Mountain Wood Tick ( Dermacentor andersoni), American Dog Tick ( D. variabilis), Lone Star Tick ( Amblyomma americanum), Black-legged Tick ( Ixodes scapularis) and Western Black-legged Tick ( I. pacificus) |
| Mode of Infection: | Bite from an infected Tick |
| Incubation period: | 2 to 7 days after tick begins to feed. Children will exhibit symptoms sooner. |
| Symptoms: | Begins as weakness in the legs, then progressively ascends until the entire body is paralysed. Once symptoms start to occur, they progress quickly over several hours to days. Symptoms can be only ataxia (loss of co-ordination) without muscle weakness. |
| Treatment: | Locating and removal of the tick. Symptoms will resolve in hours to days. If offending tick is not removed, paralysis can progress to respiratory failure. Remove tick and keep for identification. |
| Immunization: | None |
| Further information: | |
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| Name: | Babesiosis |
| Agent: | Cases of Babesiosis have been reported in British Columbia. Lintraerythrocytic parasitic infection caused by protozoa of the genus Babesia and transmitted through the bite of the Ixodes tick |
| Host: | Deer, blood transfusions |
| Mode of Infection: | Bite of the Ixodus tick, commonly known as the deer tick. |
| Incubation period: | 1 to 4 weeks |
| Symptoms: | Symptoms similar to Maliria – fatigue, anorexia, dark unrine, sensitivity to light, depression, nausea & vomiting, cough, fever, jaundice. |
| Treatment: | Can be treated with Anti-malirial drugs, antibiotics and quinine. Most cases will improve without treatment. Approximately 25% of the infected cases reported are co-infected with Lyme disease. Note: European Babesiosis 53% of infections are fatal because the infection is caused by a different strain of Babesia in Europe. |
| Immunization: | None |
| Further information: | |
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| Name: | Leptospirosis (bacterium) |
| Agent: | Bacterium of the genus Leptospira |
| Host: | Many different kinds of animals carry the bacterium. |
| Mode of Infection: | Exposure to water contaminated with the urine of infected animals. Leptospira organisms have been found in cattle, pigs, horses, dogs, rodents, and wild animals. |
| Incubation period: | 2 days to 4 weeks |
| Symptoms: | Initially begins abruptly with fever and other symptoms. May occur in two phases; after the first phase, with fever, chills, headache, muscle aches, vomiting, or diarrhea, the patient may recover for a time but become ill again. If a second phase occurs, it is more severe; the person may have kidney or liver failure or meningitis. This phase is also called Weil’s disease. |
| Treatment: | Treated with antibiotics, such as doxycycline or penicillin |
| Immunization: | None |
| Further information: | http://www.cdc.gov/leptospirosis/index.html |
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| Name: | Baylisascaris Infection or Racoon Roundworm |
| Agent: | Baylisascaris – type of intestinal roundworm |
| Host: | Baylisascaris procyonis is found in Racoon’s intestines. |
| Mode of Infection: | Infection is spread when infective eggs are accidentally ingested by a person or animal |
| Incubation period: | 2 – 4 weeks after ingestion |
| Symptoms: | Depending upon how many eggs have been ingested and where the larvae migrate to will depend upon severity of symptom. Possible death can occur in some cases. |
| Treatment: | No effective, curative treatment is yet available. |
| Immunization: | None. |
| Further information: | |