|
Reptiles and Small Mammals
Page 2
Go to page 1 (or use the article links, above.)
Go to In the News to find out what's happening in medicine.
Check out the articles in Seasonal Concerns.
Exotic Pet Care Sheets
The Animal Library has some great care sheets for hedgehogs, ferrets, box turtles, rabbits, guinea pigs, and sugar gliders. The AnimalLibrary.com is the animal health care resource of the Southern California Veterinary Medical Association,
Texas Veterinary Medical Association, and Hawaii Veterinary Medical Association.
Go now to the Exotic Pet Care Sheets.
Can Your Pet Make You Sick?
Zoonotic diseases, also known as zoonoses, are any diseases that can be spread between animals and humans. Familiar examples include salmonellosis, ringworm, rabies and plague. In the last decade, public attention has focused on the potential transmission of diseases such as salmonellosis from reptiles to their owners.
Less attention and risk are associated with small animals compared to imported reptiles. However, sometimes pet owners wonder if they can catch a disease from a pet such as a hamster or rat. A host of potential pathogens including bacteria, internal parasites and fungi can be transmitted between animals and people, although no parasitic protozoan diseases are likely to be acquired by pet owners from small animals.
The following is a brief review of the ailments that have the greatest potential of being observed.
Ringworm
Ringworm - Microsporum spp and Trichophyton spp - is a highly contagious fungal disease that can be transmitted to people through direct contact with infected animals, and indirectly by spores in the hair or scales shed from infected animals. The ringworm fungi primarily affects the outer layers of skin, hair and nails. The name of the disease refers to the discrete, circular or ring-shaped pattern of hair loss and redness caused as the fungus grows in the skin. The lesions are usually hairless and scaly in the center. It can be a self-limiting disease with spontaneous remission occurring within one to three months of onset. Some animals can be asymptomatic carriers.
Ringworm is more common in dogs and cats than in small animals, but it
has been recorded in ferrets and rabbits. The condition must be diagnosed and treated by a veterinarian. Diagnosis is based on skin scrapings, and one species will fluoresce under ultraviolet light. Some cases are resistant to treatment, lengthening the time until cured. A topical or oral antifungal medication is used, and the animal's environment must be disinfected with a 10 percent bleach solution. In humans, ringworm affect the scalp. or body. Children, immunocompromised individuals and the elderly are most susceptible.
Sarcoptic Mange
Sarcoptic mange is caused by a mite. It is transmitted to people by direct con-tact with the mite. In small animals, the general symptoms include hair loss and itchy skin at the site of infestation. In ferrets, one form affects only the feet and is known by the common name of foot rot. The paws become inflamed, swollen and crusted. In severe cases, the nails can become deformed. Not only must the affected animal be treated by a veterinarian, the animal's cage must be thoroughly cleaned and sterilized.
Salmonellosis
Salmonellosis, is a bacteria that can affect the gastrointestinal tract of humans. A variety of small animals are potential vectors, although cases of transmission from small animals to humans are infrequent when compared to reptiles such as iguanas.
Salmonella includes more 2,000 different species of bacteria and, of these, dozens have been isolated from reptiles. It is not surprising then, that contracting salmonella bacteria is always a danger for people who own reptiles.
Salmonella bacteria is shed in the feces and can be transferred by an iguana's feet, if it walks through matter. This is one reason why a clean cage is so important.
Salmonella also can be transmitted through scratches or bites. Iguana owners should not put their pets near their mouths or kiss them. In addition, they should not bathe their pets in the bathtub or sink-especially the kitchen sink-without disinfecting it for human use afterward. Iguanas should not be allowed to run loose in the house.
Owners should know that washing their hands with antibacterial soap after handling an iguana is one way to avoid catching salmonella. Children less than 5 years old should not be allowed to handle iguanas at all because they often stick their fingers or the animal's toes into their mouths.
Young children, pregnant women and immunocompromised people (those with HIV, for example) are at risk of infection and, therefore, should not keep iguanas as pets.
Please see the article below for more detailed information about Salmonella bacteria in reptiles.
Leptospirosis
This disease is caused by bacteria called leptospores, which are found in wild and domestic rodent reservoir hosts. The leptospores are carried and shed in the urine of healthy hosts. They can contaminate water supplies.
Species Specific Zoonotic Potential
Rats have historically been thought of as dirty animals. Many customers wonder whether rats can still transmit dreaded diseases such as bubonic plague. However, the disease problems associated with wild rat populations are rare to unknown in pet rats. Rats can potentially harbor salmonellosis. The most likely adverse zoonotic ailment among pet owners is that some individuals might be allergic to their rat's urine or dander.
Pet mice can potentially carry salmonella. However, they rarely transmit any zoonotic diseases. Some pet owners develop allergies to their mouse's dander and urine.
Gerbils represent few potential health hazards to people keeping the animal as a pet. Salmonella and tapeworms have rarely been reported in colonies of gerbils.
Hamsters have a low zoonotic potential. Occasionally, salmonella and tapeworm have been documented in large colonies of hamsters, but such conditions are not typical of hamsters kept as pets
Rabbits can transmit ringworm sarcoptic mange and salmonella. Because rabbits often struggle if held improperly, pet owners can be scratched. The scratches can then become infected from bacteria.
Some pet owners develop allergic reactions to guinea pig hair and skin. Although rare, salmonella is a potential pathogen in guinea pigs. Two species of mange mites, the mange mite, Trixacarus caviae, and the sarcoptic mange mite can affect guinea pigs and be transmitted to people.
Influenza is the only documented zoonotic disease of ferrets. Ferrets are susceptible to the influenza virus, and the potential for transmission from humans to ferrets is much greater than the transmission from ferrets to humans.
Final Thoughts
Environmental stress such as overcrowding, poor sanitation, malnutrition, and concurrent infection are predisposing factors to most diseases, including those with zoonotic potential. Obtaining pets from clean sources is the first step in preventing diseases. The second step is maintaining the animals in a sanitary environment in the pet store. Educating owners on how to properly care for their pets in their own homes, including how to recognize any signs that could indicate their pets are sick can help reduce the likelihood of zoonotic diseases in small animals.
This information was largely taken from an article written by Susan Fox in the March 2000 issue of Pet Business.
Back to Top
Salmonella Bacteria and Reptiles--
Keeping Reptile Owners Safe
Most, if not all, reptiles carry Salmonella bacteria in their intestinal tract and intermittently or continuously shed these bacteria in their feces. Salmonella bacteria usually do not cause any illness in reptiles but can cause serious illness in people.
Salmonella bacteria are easily spread from reptiles to humans. Humans may become infected when they place their hands or other objects including food items that have been in contact with reptile feces in their mouths. For example, infants have become infected after drinking bottles of infant formula that became contaminated during preparation, because individuals who prepared the formula had not washed their hands after touching a reptile or because reptiles were allowed to walk on kitchen counters. For Salmonella bacteria to spread from reptiles to humans, the bacteria must be ingested. Therefore, simply touching or holding a reptile will not result in spread of the bacteria unless something contaminated with reptile feces or the reptile itself is placed in the mouth.
Most Salmonella infections in humans are mild, self-limiting illnesses characterized by diarrhea, fever, and abdominal cramps. However, infection can spread to the bloodstream, bone marrow, or nervous system, leading to severe, and sometimes fatal, illness. Such severe infections are more likely in infants and individuals with a compromised immune system (for instance, bone marrow transplant recipients, people with diabetes mellitus, people infected with HIV and chemotherapy patients).
Unfortunately, Salmonella bacteria cannot be eliminated from the intestinal tract of reptiles. Administration of antibiotics to eliminate these bacteria has been unsuccessful and may result in emergence of Salmonella bacteria that are resistant to antibiotics. Attempts to raise or identify reptiles that do not carry Salmonella bacteria have also been unsuccessful; therefore, bacterial culture of fecal specimens in an attempt to identify reptiles that are not carrying Salmonella bacteria is not recommended.
Fortunately the spread of Salmonella bacteria from reptiles to humans can be easily prevented by using the following routine precautions:
- Always wash your hands with hot, soapy water after handling reptiles, reptile cages and equipment, and stool from reptiles.
v Do not allow reptiles co have access to the kitchen, dining room, or any other area in which food is prepared. Also, do not allow reptiles to have access to bathroom sinks and bathtubs or to
any area where infants are bathed. Consider keeping your reptiles caged or limiting the parts of the house where reptiles are allowed to roam free. Always wash your hands after coming into contact with any area where reptiles are allowed to roam free.
- Do not eat, drink, or smoke while handling reptiles, reptile cages, or reptile equipment. Do not kiss reptiles or share food or drink with them.
- Do not use the kitchen sink, kitchen counters, bathroom sink, or bathtub to bathe reptiles or to wash reptile cages, dishes, or aquariums. Reptile owners may wish to purchase a plastic basin or tub in which to bathe or swim their reptiles. Waste water and fecal material should be disposed of in the toilet instead of the bathtub or household sink.
- The Centers for Disease Control and Prevention recommends that children less than 5 years old avoid contact with reptiles and that households with children less than 1 year old not own reptiles. The Association of Reptilian and Amphibian Veterinarians encourages reptile owners with young children to discuss steps to minimize risks associated with owning reptiles with their veterinarian and their physician. Children should be supervised when they are handling reptiles to ensure that they do not place their hands or objects that a reptile has contacted in their mouths. Reptiles should not be kept in child care centers.
- Immunocompromised people should avoid contact with reptiles.
- Follow instructions from your reptile's veterinarian concerning proper diet and environment for your reptile. Healthy reptiles living in proper environments are less likely to shed Salmonella bacteria.
Information in this handout is not meant to discourage reptile ownership. With a few exceptions (eg, infants and immunocompromised individuals), most people have a low risk of acquiring salmonellosis from reptiles, but this risk can he reduced even further by following simple precautions. Reptiles can be safely kept as pets, but reptile owners should be aware of methods for reducing the risk of acquiring Salmonella bacteria from their reptiles. This article was developed by the Association of Reptilian and Amphibian Veterinarians and the Centers for Disease Control and Prevention and is intended for informational purposes only; please seek advice from your physician and your reptile's veterinarian if questions or problems occur.
Back to Top
Determining Reptile Gender
The relationship that develops between humans and pets does not recognize many boundaries. We realize the power of the human-animal bond and strive to provide pet owner with the knowledge and support required to care for their pet so that it will be rewarding. The most common question asked by a prospective new pet owner is:
What is the sex (gender) of the animal?
Humans have long had a desire to name their pets, which is the first step to establishing the human-animal bond. Yet nothing is more disheartening to a pet owner than to find out that the pet they have been calling Brutus should be more appropriately named Beulah.
Anatomy Lesson
Gender determination in reptiles requires some background knowledge of reptile anatomy. Male snakes and lizards have hemipenes, paired copulatory organs, whereas chelonians, tortoises, terrapins and turtles have a singular penis. The copulatory organs of the snake and lizard are located in the base of the tail and the copulatory organ of the chelonian is located cranial (toward the head) to the vent. The methods to differentiate gender vary from group to group, even though they may share a similar type of reproductive organ.
The most common way to differentiate gender in snakes is to use a commercial probe set. The probe is gently inserted into the vent by the veterinarian and directed laterally, off-midline, in the direction of the tail. The probe will travel deeper in the male - greater than four scale lengths - than in the female - less than three to four scale lengths. The tail of the male snake is often wider and longer than the female's tail. Some herpetoculturists claim that they can determine the gender of a python based on the size of their spurs - the claws located at the level of the vent. However this technique is not accurate. Juvenile snakes can be difficult to probe because of their small size. Experienced handlers may attempt to evert the hemipenes of a juvenile male snake using their thumb or finger. However, excessive pressure can result in damage, and this technique should only be attempted by individuals with experience.
Visual Clues
Although male lizards have reproductive organs similar to snakes, they cannot be probed with the same degree of accuracy. The determination of gender in lizards is often based on sexually dimorphic characteristics - obvious external differences. Male chameleons such as the panther chameleon, often have more colorful skin patterns than females, or, as seen in the Jackson's chameleon, they possess ornate horns. In certain species of lizards, males possess specialized scale patterns. The adult male green iguana develops specialized femoral pores, located on their inner thighs that produce a waxy substance to mark their territory. These pores become well-developed in the male after approximately 8 to 10 months of age. Many of the different species of male geckos, including the leopard gecko, possess pre-vent pores. Male lizards may also be differentiated from females by the presence of hemipenal bulges in the base of the tail, which become readily apparent as the animal matures.
There are a number of different techniques used to determine the gender of a chelonian. Male tortoises often have an indentation in the middle of their plastron, bottom of the shell, which enables them to mount a female. In the Eastern box turtles, Terrapene carolina, the iris color in the female is often amber, while in the male it is red. Red-ear slider, Trachemys scripta elegans, males are much smaller than females and develop long front claws. In cases where the determination of gender cannot be made based upon sexually dimorphic characteristics, the location of the vent can be used. The vent of a male chelonian will extend, beyond the length of the carapace, with the total tail length being longer than that of a female.
These techniques described to determine the gender of a reptile will work in most cases, although there are exceptions.
This article was written by Mark A. Mitchell, DVM and was published in Pet Business in March 2000.
Back to Top
Aggression in Iguanas
Iguanas can be very aggressive and they may lash their tails or bite if they feel threatened. Their mouths are full of sharp teeth, so a large iguana bite will require numerous stitches and leave a lifelong scar.
Male iguanas should never be housed together and should not be in the same area of the house, if possible. Sexual aggression between adult male iguanas (especially single adult males in household) and human females can become a problem. Iguanas that are extremely tame can appear to become enraged when a woman releases pheromones during her menstrual cycle. This can be a frightening experience, especially for someone not familiar with iguanas.
Even the most docile iguana can scratch. Pet owners should, therefore, keep their iguana's nails trimmed. A
dog or cat nail trimmer or an electric nail-melting tool works well. Scratches should be disinfected immediately, and reptile owners should be sure to update their tetanus shots.
Pet iguanas are not the best choice for novice reptile owners. Leopard geckos and corn snakes, on the other hand, make excellent pets for beginners.
People who decide to purchase green iguanas should be aware that they are making a long-term commitment - and not just buying a disposable pet.
This article was written by Timothy E. Hoen and first appeared in Pet Age. Mr. Hoen is president of the Maryland Herpetological Society and president the M.A.RS. Preservation Fund Inc.
Back to Top
Care of the Green Iguana
Pet Qualities
The green iguana seems to possess an intelligence not usually seen among reptiles. Iguanas can become quite tame and often will interact with their owners. Often, they're content to ride around on their owners' shoulders, and appear to delight in being rubbed or scratched gently. Iguanas won't, however, return affection in the way of nuzzling or cuddling. But they do tend to learn household routines, and will know when it is mealtime, bedtime or time to go outside. Iguanas are often happy to perch on the back of the sofa or curtain rod, surveying the goings-on in the home.
A note of caution: Some iguanas, particularly males, can become aggressive at times, especially during mating season. Before purchasing one, be sure that you can handle a six foot lizard with the potential for inflicting severe wounds. There are many iguana rescue clubs in the country, the end result of too many people buying a lizard without realizing the care that is involved. For inexperienced reptile owners, a better first choice would be the bearded dragon or the leopard gecko.
A tame iguana will allow itself to be picked up and held without struggling, scratching, tail whipping or biting. Most iguanas seem to be able to identify individual people, and will react quite differently with their owners than with strangers. While an iguana may allow itself to be handled by its owner, the tame lizard may not take kindly to being held by a stranger.
Because iguanas benefit greatly from direct unfiltered sunlight, taking your iguana outdoors for some supervised time in the sun is an excellent idea. Once an iguana has heated up, however, it becomes more alert and active and may bolt away from its owner. There are several different kinds of harnesses available, and if your iguana will tolerate one they're a great method of restraint.
Green iguanas are great pets for folks living in apartments, condos and townhouses. They are very quiet and rarely destructive. Their exotic appearance is very appealing to people with a taste for the unusual. Iguanas are not difficult to maintain as long as their physical needs are met adequately. However, meeting these physical needs: light, heat, and nutrition can be challenging for a new owner. Please discuss any question you have with a veterinarian.
Cage and Substrate
There are many suitable ways to house an iguana. Our advice to owners of new hatchlings is to buy or build the largest cage they can accommodate. Many owners start out by purchasing a glass aquarium. Unfortunately, even a 20-30 gallon tank will be rapidly outgrown by a robust lizard. Another problem with glass is that they are heavy and cumbersome to clean. However, it is easier to control and maintain the correct temperature for a hatchling if it is kept in a glass or plastic tank for the first few months.
A cage can be a simple structure, or it can be designed and constructed to complement any decor. Pet stores can sometimes order custom-built cages, and some custom cages are advertised in reptile magazines. Cages may have a wood frame, or frames can be constructed out of aluminum. Plexiglas or soft plastic mesh can be used to enclose the cage. Cages should be designed (or purchased) with ease of cleaning in mind. Because iguanas are arboreal, cages should be tall enough to allow them to climb. Cages should be at least two times the length of the iguana and as deep as the iguana is long.
The cage bottom should be lined with an absorbent material to facilitate cleaning. Newspaper or butcher paper is convenient, but paper is not always the most aesthetical choice. Other substrates choices are orchid bark, alfalfa rabbit pellets, plastic astroturf or indoor/outdoor carpeting. If carpeting or artificial turf are used, make sure that the iguana cannot eat the material. Some carpets tend to unravel; strands can be dangerous if ingested. Substrate material, such as gravel, corn cob bedding, crushed walnut shells or sand should never be used, because iguanas may ingest them, resulting in impaction or other gastrointestinal problems. Another substrate that should never be used is cedar shavings (the oil is toxic). Some iguanas tend to defecate in the same place every time, which makes clean up easier. Clean the cage regularly. Some iguanas do tend to relieve themselves in water, so by removing the animals from their cages and soaking them frequently, cleanup can be simplified.
Branches and basking areas should be provided. Shelves are often appreciated for lounging. A hide box should be available to the iguana where it can get out of view and feel secure. The hide box should be in a warm area of the cage. Live plants may be used for decoration and to provide a more natural setting. Be sure to choose nontoxic plants, because the iguana is sure to taste them. Silk plants are a poor choice since iguanas cannot distinguish between live and artificial and often try to ingest them.
Heat and Light
Iguanas, like all ectotherms, thermoregulate by moving toward or away from heat sources and temperature zones, and engage in basking. Each species of reptile has its own Preferred Optimal Temperature Zone (POTZ). An iguana must reach the POTZ for correct digestion, growth, reproduction, healing and for the proper functioning of the immune system. Wild iguanas derive their heat from above, from basking in the sun not from lying on rocks heated from the sun. It is best to provide your iguana with a full-spectrum, incandescent light bulb for basking. Hot rocks, or other methods for heating an iguana on the abdomen, are not the best choices. Iguanas also need ultraviolet light. Make sure that the lizard does not have direct access to the light bulb, but provide an area where it can bask close to the light. Purchase a fluorescent light designed for reptiles. Place it in the cage in a way that the light is not filtered through glass, plastic or tight weave screen. Ultraviolet light is necessary for the proper absorption of calcium. Lights should be turned on for 12 hours, then off for 12 hours. It is important to realize that there is no perfect artificial light that can replace natural sunlight.
To create a thermal gradient indoors, place a source of substrate heat (tape pads or rocks) and an incandescent light bulb in a reflector on one side of the cage. Place a couple of thermometers in different areas of the cage to measure temperature in different zones. During the day, the hottest temperature zone in the cage should be around 98.5 degrees Fahrenheit, and the lower zone should be 80 degrees Fahrenheit. With this range of temperature, a healthy iguana will be able to maintain its body temperature at the correct level for proper internal functioning. In addition to lighting, a ceramic heater that screws into a regular light socket is an excellent addition to the cage to provide heat, but no light, for cool nights when supplemental heat is needed. Substrate heaters should be left on 24 hours per day, but all light bulbs should be turned off at night. At night you are shooting for a 10 to 15 degree drop from daytime temperatures.
The last consideration regarding heat and light is ventilation. There should be adequate ventilation and circulation of air in the cage to prevent high humidity that will encourage the growth of pathogens. Humidity should be in the 50 to 70 percent range.
Diet and Nutrition
Iguanas are vegetarians, specifically folivores. Folivores eat leaves primarily. They are hindgut fermenters, and to correctly process their food, they do require high environmental temperatures. Older books describe hatchling iguanas as insectivores that become herbivores as they mature. Although this is incorrect, it does not mean that a pet will not develop a taste for inappropriate food items. Feeding an iguana anything but vegetable matter or commercially prepared iguana diets should be strictly forbidden.
Hatchlings up to 14 inches should be fed finely chopped food twice daily. Juveniles up to 3 feet in length should be fed fine to medium chopped food once daily. Adults over 2 1/2 years of age or over 3 feet in length can be fed coarsely chopped food every other day. All plant material should be washed and chopped in a food processor to thoroughly mix the ingredients and prevent the iguana from selecting specific items.
Approximately 50 to 60 percent of the diet should consist of dark-green leafy veggies. Choose at least two of these: collard greens, turnip greens, mustard greens, bok choy, Swiss chard, dandelions greens, escarole, parsley and alfalfa pellets. Beet greens and spinach contain oxalates that bind calcium, so these greens should only be offered occasionally. Kale, Brussel sprouts, broccoli, cabbage, and cauliflower bind with iodine and should be offered sparingly. Approximately 30 to 40 percent of the diet should be chosen from this list: frozen mixed vegetables, squash, sprouts, carrots, cooked sweet potato, green and red peppers, peas, beans, corn, and green beans. Fruits should make up to 10 to 15 percent of the diet and may include papayas, mangos, apples, peaches, pears, plums, strawberries, bananas with the skin, tomatoes, grapes, kiwi, blueberries and guavas. Whole grain breads and natural bran cereals can be offered in moderation. In place of grains, commercially prepared iguana food can be a nutritious part of the diet. Iguanas often enjoy hibiscus flowers and leaves, rose petals, geraniums, nasturtiums, squash blossoms and carnations. These can be offered for variety but should not be fed daily.
Most iguanas obtain water through the water content in the foods they eat, so many won't drink from a dish or tub. If a commercial diet is fed, keep in mind that most are fed dry, which will decrease the lizard's water intake. It may be better to feed a canned moist food or to moisten the dry diet prior to feeding.
Live food is not necessary for green iguanas. Some enjoy crickets or pinkie mice, but these sources of animal protein are poor dietary items for this species.
Handling Hints
Iguanas should never be picked up by the tail. The tail of a young iguana may break off. The tail will regenerate, but will not grow back as long or as brightly colored as the original.
Encircle hatchling iguanas gently with your hand to prevent them from darting free. Larger iguanas should be held so the whole body is supported. This makes them feel more secure. Don't pick up iguanas by their limbs; this can cause injury.
Frightened iguanas may try to bite or scratch. Bites from large specimens can be quite painful and inflict serious wounds. Scratches can hurt, and a whip from the scaly, powerful tail can raise a welt. You may want to consider having your iguana's nails clipped periodically.
Zoonotic Diseases and Precautions
Green iguanas can harbor bacteria that can cause disease in humans. One genus of bacteria, Salmonella, is most dangerous in immunosuppressed adults, infants, children and geriatrics. Tests for Salmonella can result in false negatives, so it's best to assume that all iguanas are potential carriers. To minimize risk of exposure, do not clean reptile equipment and supplies where food is prepared for humans. Do not share sinks and bathtubs to soak or clean tanks. Wash hands thoroughly after handling an iguana, and don't touch your face prior to washing with antibacterial soap. Do not allow young children to handle iguanas until they can understand the concept of correct handling and sanitation.
Pinworms and roundworms found occasionally in green iguanas are not transmissible to humans. Rarely, intestinal protozoa may be found in green iguanas that can be contagious to humans.
Bathtubs, sinks or other areas where the iguana has been should be disinfected with bleach solution (1/2 cup to one gallon water). Be sure to rinse well after bleaching.
Reproductive Problems
Reproductive problems are common in many female iguanas. Many will lay eggs, even without the presence of a male (similar to chickens). For many iguanas, the stress of laying eggs in an artificial environment can shorten their life dramatically. It's best to schedule a veterinary appointment to discuss the best care, and often the best advice is to get her spayed. The procedure is similar to that of spaying a dog or cat, and at Harmony Animal Hospital our laser surgical equipment makes the procedure safer than it's ever been.
Male iguanas can also be neutered, which will often lead to a calmer disposition with less aggressive tendencies towards humans.
Back to Top
Go to page 1
|
