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Snake Parasitic Diseases

Parasitic Diseases: Snakes can be hosts to a large number of parasites, representing a bewildering variety of organisms that can cause many problems. A large number of one-celled organisms (protozoa) can cause serious diseases of the digestive, respiratory, reproductive and vascular blood and bloodstream) systems of snakes. Flukes cause illness in the respiratory and urinary systems. Tapeworms parasitize the digestive system. Roundworms and related parasites inhabit the digestive tract, but their juvenile states can cause disease to other organs (especially the lungs) during the course of their migrations. Large numbers of mites and ticks parasitize the skin and scales of snakes, and create disease by feeding on the host's blood. Signs of parasitism depend on the parasite and body tissue involved. External parasites are usually easy to diagnose, though immature stages of mites may lie dormant under scales or just inside the eye cavity. Visual inspection of the skin and scales, with or without a magnifying lens, is usually all that is necessary. Internal parasite problems require examination of various specimens, most often blood, feces, urinary tract products, and washings from the windpipe and lungs. Special laboratory procedures are necessary to process these specimens. Microscopic examination is usually necessary.

Most parasites of pet snakes and snakes kept in zoological collections are carried with them into captivity. These snakes were either parasitized before being collected in the wild or became parasitized while being held in the generally crowded wholesale and retail channels. Pet snakes living singly in homes are very unlikely to develop parasite problems in these relatively isolated environments. Exceptions to this generalization include pet snakes exposed to parasitized snakes and their excretions, or to the specific organisms (called "vectors") necessary for parasites to complete their life cycles. In most cases, the vector must bite the uninfected snake for the snake to become parasitized. It is also possible for a captive snake to become parasitized by eating certain prey species that harbor the larval stage of a given parasite. Newly acquired snakes should be thoroughly examined and evaluated by a veterinarian for external and internal parasites as soon as possible after acquisition. All detected parasitism should be treated, if possible. No snake should be introduced into a collection until a veterinarian has examined it, and until it has been quarantined for a minimum of 8 weeks and remains healthy during this period. Strict attention to hygiene and sanitation and a proper diet usually contribute to optimum health, even in the face of mild to moderate parasitism. Because the subject of parasitism is so extensive, only several of the more common parasite problems of captive snakes will be specifically mentioned:

Amebiasis: Amebiasis is one of the most significant parasite problems of captive snakes. This highly contagious disease is caused by a microscopic, one-celled organism (protozoan) called and ameba. Eating contaminated food and water containing the infective stage of this parasite easily infects snakes. The organisms cause extensive damage to the intestinal lining and liver. Secondary bacterial infections are very common and contribute significantly to the severity of the disease. Signs of amebiasis include listlessness, inappetence, and foul-smelling feces containing mucus and blood. A veterinarian may be able to diagnose this disease by having the laboratory examine specially prepared samples of feces. Sometimes examination of tissue sections of the intestine or scrapings from the lining of the intestine of a deceased snake is the only way the diagnosis can be confirmed. This underscores the importance of performing autopsies on snakes that have died, especially when there are other snakes in the collection whose lives may be threatened. Many snakes native to the American Southwest harbor these organisms but apparently do not suffer from the disease. Crocodiles and certain turtles are similar "carriers." Hobbyists must, therefore, exercise caution when housing snakes with these species to avoid an outbreak of amebiasis. Certain water snakes, as well as boa constrictors and pythons are especially susceptible to this disease. Amebiasis is treatable, requiring the expertise of a veterinarian. Specific antiprotozoal medications and antibiotics are used. Enclosures used to house infected snakes should be steam cleaned and disinfected with a 3% bleach solution.

Trichomoniasis: One of the most commonly recognized parasites of snakes is another protozoan, Trichomonas. This organism is often noted in the stools of snakes when routine direct examinations are undertaken. Infection with Trichomonas may result from ingestion of mice and rats, both of which often harbor the parasite without showing signs of illness. Infected snakes may exhibit no signs or those associated with gastrointestinal disease (inappetence, vomiting, and diarrhea). Some infected snakes may also have bacterial disease at the same time. Some experts remain unconvinced that this parasite, by itself, can produce disease in snakes because infected snakes are often suffering from amebiasis at the same time. The most prudent course of action is to treat all snakes harboring the parasite. Fortunately, the treatment for trichomoniasis is usually effective in eliminating the organism that causes amebiasis. A veterinarian should be consulted regarding diagnosis and treatment of this parasitic disease.

Snake Mite Infestation: Snake mites are tiny spider-like organisms that reside on and between the scales of snakes and tend to also congregate around their eyes. They are relatively easy to see with the unaided eye but a magnifying lens aids in their identification. Mites are the most common and most dangerous of the external parasites of captive snakes. These mites feed on the blood of their hosts, causing anemia (often sever with heavy infestations). Blood feeding can also transmit viruses, at least one very serious disease-causing bacterium, and blood parasites. The snake mite completes its life cycle on its host. The females, however, lay up to 80 eggs off the snake within the immediate environment. This is one reason why particulate floor coverings (corncob material, pebbles, etc.) are not recommended. These substrates provide too many hiding places for the mites and their eggs.

Snakes that are most likely to be seriously compromised by this external parasite are those that have been recently imported and those housed under crowded, unhygienic conditions. Heavily parasitized snakes are also likely to be adversely affected when they are suffering from malnutrition and/or other diseases at the same time. Veterinarians must be consulted when these various circumstances arise. These snakes must be carefully examined and thoroughly evaluated so that underlying disease and problems with husbandry can be identified and corrected. Further, the recommended treatment can often be injurious, especially to snakes suffering from debility and/or disease. The veterinarian must perform a thorough physical examination and may recommend a blood analysis to fully evaluate the patient, the advisability of treatment and the least harmful method of treatment for mites. Several treatments are available for snake mites. One popular method involves suspending a No-Pest Strip (Hot Shot) above or adjacent to the snake's enclosure for 2-5 days. One expert recommends a "dosage" of 0.2 inches of commercial strip per 10 cubic feet of enclosure. An alternative is to place a 1-inch section of a No-Pest Strip within a 35-mm film container with multiple perforations and suspend it inside the enclosure for 2-5 days. These products should be used cautiously, however. They can be especially toxic to severely ill and debilitated snakes. Flea sprays formulated for use on dogs and cats can be applied to a small towel and the chemical can be wiped onto the skin and scales. This should be repeated about 10 days later. During treatment, paper or towels must replace any particulate floor covering (gravel, crushed corncob, wood shavings, etc.) within the enclosure. All water containers should also be removed. The enclosure itself should be thoroughly cleaned and fumigated with 10-15% solution of formalin and hot water. After a thorough rinsing, the enclosure should be allowed to completely dry before it is re-inhabited. Treated snakes should be closely monitored for several months for signs of re-infestation and mite-related disease.

Snake Tick Infestation: Ticks resemble oversized mites and occupy many of the same sites on the skin and scales of snakes as mites. They are often found just inside the mouth, nostrils or vent. Even under conditions of captivity, ticks rarely reach the burdensome numbers reached by mites. Recently imported snakes are usually the most heavily parasitized. Like mites, ticks feed on blood of the host snake and can cause severe, life-threatening anemia. Their blood-feeding habit enables them to transmit certain blood-borne diseases to snakes. Manual removal of each individual tick is the most expedient treatment for tick infestations. The hobbyist must exercise great care in performing this task. Simply pulling off the tick leaves the tick's mouth parts embedded in the skin. A small amount of alcohol applied to the exposed parts of the tick causes it to relax and facilitates removal. The treatment methods recommended for mites are also effective. Parasitized snakes usually require a minimum of 4 days exposure to No-Pest Strips to kill ticks. Enlist the services of an experienced veterinarian for a thorough pretreatment evaluation of the snake, especially if the use of a No-Pest Strip is anticipated.