Health Concerns to be Aware of When Working With Wildlife
Helminth Diseases (parasitic)Helminths are worms. All species of wildlife carry their own complement of helminth intestinal parasites. Our domestic animals also have specific kinds of roundworms. There are two forms of disease produced by these parasites. Cutaneous larval migrans is a penetration of the skin with the parasite undergoing a localized migration in or just under the skin, creating an inflammatory reaction that is self-limiting. Visceral larval migrans occurs when the eggs of a parasite are ingested and further penetrate the intestinal tract, where they undergo a migration through the animal’s organs. The amount and severity of the disease depend on the organs affected. Although only Baylisascaris infection is described below, any roundworm is capable of tissue migration. Therefore, handling of fecal matter should always be with the protection of gloves.
* * CUTANEOUS AND VISCERAL LARVAL MIGRANS
INFECTIOUS AGENT Baylisascaris procyonis (Raccoon Roundworm) (others also, see above)TRANSMISSION Skin penetration, oral ingestion of eggs. The roundworm of raccoons is reported to infect at least 70 percent of raccoons in some areas. For the raccoon, it causes few problems. However, it can cause serious illness to other animals, including humans. The adult worm can produce six million eggs per day, passing them in the host’s feces.
SYMPTOMS If accidentally ingested by another species, humans included, the larvae hatch and penetrate through the intestine, migrating to many parts of the body. If these larvae migrate into the eye, brain, or spinal cord, there can be serious, irreversible consequences. Blindness, central nervous system disease, or even death can result. Children have died due to this migrating parasite. In adults, eye problems are a more common result. Other species have roundworms that can sometimes penetrate the skin, causing a localized self-limiting skin irritation (Cutaneous larval migrans) in man.
PREVENTION
- Avoid contact with feces, especially raccoon. Use disposable gloves when handling fecal matter.
- Good personal hygiene in handling any wildlife species.
- Deworm all incoming raccoons with an effective antihelminthic drug such as Strongid-T suspension (Pfizer) every two weeks.
- Thoroughly clean and disinfect and cages, carriers, or areas occupied by raccoons. The ova are very resistant, however, to decontamination procedures. Recommended procedures are autoclaving, flaming with gasoline, propane, or fuel oil, boiling in lye water (1 Ib./20 gal. water), or boiling in Lysol. Cages should NOT be used again for any other species (other animals may become infected and show misc. CNS signs leading to death; these animals cannot transmit the parasite in their feces.)
- Keep children from handling raccoons or from exposure to raccoon feces; e.g., cover backyard sandboxes.
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Viral Diseases
Viruses are known to infect a wide range of hosts, including humans and wild animals. The usual mode of transmission and dissemination is through the direct contact or aerosol contact with others of their own species. Wildlife populations, such as waterfowl, experience epizootics (epidemics in wildlife) caused by viruses. Duck plague, or duck viral enteritis, may cause large die-offs in a localized area. People also experience viruses; for example, the upper respiratory viruses where epidemics are not uncommon. There are only a few viruses that are common to humans and wildlife; however, since they have no specific cure, they can be very serious.
* * RABIES (Hydrophobia) (Bite Wound Disease)
INFECTIOUS AGENT
Rhabdovirus
HOST Any mammal, usually carnivores; in ND, highest incidence is in skunks, foxes, bats, and raccoons.
TRANSMISSION Bite wounds, infected saliva in cuts or skin abrasions, aerosol in bat caves.
SYMPTOMS Rabies is almost always a fatal disease of mammals, including humans. The disease progresses from fever and malaise, to paresis and paralysis of the muscles, to delirium and convulsions and eventual death due to respiratory muscle paralysis. In animals, ANY abnormal behavior is cause for concern, especially a lack of fear of humans and normally nocturnal animals being out during the day. Domestic animals once formed the largest reservoir for the disease, but, since the 1960’s, wildlife species, especially skunks, bats, fox, and raccoons, have taken over that distinction. In 1986, 5,551 cases of rabies were reported in the United States. Of these, 91 percent were from wildlife species. Rabbits and squirrels are rarely infected. Human deaths average two cases per year.
TREATMENT (note: once the disease has developed… there is NO treatment; this is a FATAL disease)
For humans ONLY: (animal treatment is NOT an option)
- Cleanse wound thoroughly with soap and flush immediately to mechanically remove the organism.
- SEE YOUR DOCTOR!
PREVENTION Since rabies is such a uniformly fatal disease, emphasis should be placed on disease prevention. People working with wildlife regularly should consider preexposure immunization. Mass vaccination of any group can be very cost-effective. The Merieux Institute, Inc., has developed a human diploid cell origin vaccine that is highly immunogenic and effective. This vaccine has improved the positive response of the vaccine and lessened the overall side effects known with the old vaccines. The vaccine is USDA approved for 1 ml intramuscular injections in a series of three doses on days 0, 7, and 21-28, then boostered every two years. It is also approved for 0.1ml injections intradermally in the upper arm at the same time intervals as the intramuscular administration. The best protection for you and the animal in your care is to avoid being bitten!
******************************************************************Physical Physical Trauma
The last group of health-related problems involves physical trauma from a wild animal. Whenever a wild animal must be handled, the procedure must be accomplished as safely and quickly as possible. Proper techniques must be employed to minimize the risk of personal injury while, at the same time, avoiding injury to the animal. Gloves, catch sticks, caging, and other appropriate equipment may be necessary when handling a wild animal. Most of these animals will be extremely stressed, resisting every restraint attempt. In the unfortunate circumstance that a person is bitten or scratched, he or she should cleanse the wound thoroughly with soap and flush with water immediately, providing for a mechanical removal of potentially infective organisms. This should be followed by cleansing under medical supervision. The question of rabies should be addressed, depending upon the species of animal and vaccination history. After a bite wound, one of five courses should be decided upon:
- Begin post-exposure rabies prophylaxis immediately.
- Sacrifice the animal and examine the brain for rabies.
- Place the animal under observation (NOT an option with wild animals!)
- Determine when there is no risk of rabies and no action is necessary.
- Receive a tetanus vaccination or anti-toxin. The advice of a physician should be sought to help make the best possible decisions regarding the management of the injury.
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