Human Health Problems Associated with Pets


Sarcoptic Mange and People

Q: Dear Dr. Richards,

Here is my problem: I stayed overnight at my daughter's home about four weeks ago on a Wednesday night. I slept downstairs on the sofa, and as my daughter's puppy is confined to the downstairs area of her home, he slept on the sofa with me. The dog was about three months old. He kept me up most of the night because he kept jumping off and on the sofa to scratch violently. The next morning, I mentioned this to my daughter and told her he had fleas. She replied that she had already checked him for fleas and that he had none.

The following Sunday morning (4 days after my overnight stay), I awoke to a horrible, itchy rash. There were hundreds of "bites." It was primarily on my ankles & shins, my torso, my stomach, and my inner thighs. I had a couple of "bites" on my breasts, my back, and my upper arms. I had no idea what it was. It continued to get worse over the next couple of days so I went to my doctor. She thought it was an allergic reaction to soap or laundry detergent and did nothing. I hadn't changed any products. I even mentioned scabies to her but she said that the appearance and location of my rash was not consistent with scabies. She said that scabies usually produce "burrows" and are usually seen inside the elbows, on the inner wrist area, and between fingers. (I had no rash in any of those areas.) I then remembered the scratching dog, and so I contacted my daughter. She said that she, too, had had this rash shortly after acquiring the puppy, but that neither her husband nor the children had broken out. She said that her rash eventually just went away. She said that she only applied Benadryl cream to her inner thighs for the itching.

I went back to my doctor with this new information and she prescribed a medication called Elimite. I used this about ten days ago and it does not seem to be effective. Some of the original sites (of the hundreds on my body) appear to have dried up and flattened. However, I am still itching violently and it appears that I have new sites. I am frustrated, and very scared by all of this.

I have widely searched the Internet and the public libraries in my area for more information on this sarcoptic (scabies?) mite and I can't find anything which tells me (a) what is the lifespan of this mite?, (b) is there a prevention for humans?, (c) what is the treatment?, and (d) is the condition transmissible from human-to-human and/or from their clothing? (I intend to stay miles away from the dog.) I ask about "prevention" because my daughter thinks there is no problem since her own rash went away untreated. However, the family visited me this past Sunday and I noticed the children scratching. I tried not to be obvious, but I found myself afraid to hug my own grandchildren. And now...I feel that my home is reinfested after I waged an all-out war when I treated myself. I have washed tons of laundry, I have scrubbed down furniture and floors. Dr. Richards, I am tired of dealing with this. I am already under enormous stress from unrelated problems, and under the care of a therapist for grief-related emotional problems due to the loss of my husband.

Please Dr. Richards, can you give me any advice at all? I have talked to dog owners and dog breeders. Some say it cannot be passed from person to person, some say it can. Some say these mites cannot survive in human skin, some say they can and do survive and spread very well. Some say scabies disappears without treatment, some say "No way." Some people have even told me that it can only be passed from one human to another through contact as intimate as sexual relations. (I was very skeptical about this last one, because I thought of how scabies epidemics sweep through elementary schools.) Please help me.

Thank you so very much. I apologize for the length of my letter.

Sincerely, Brenda M

A: Brenda-

I think that the problem with the information you are receiving is that there is a species of sarcoptic mange that infects primarily dogs and there is a species of sarcoptic mange that infects primarily people.

The dog species of sarcoptic mange can TEMPORARILY infect humans. Usually the itchiness from this lasts about three weeks, or less. The mite can't live in humans, so it dies. If the dog remains in the household and remains infected it can continue to give its owners new mites, though -- so the itching can last longer because there is a constant new supply of mites. Cortisones are sometimes used to reduce the inflammation and itchiness. It is not necessary to kill the mites because the are going to die, anyway.

The human species of sarcoptic mange is contagious between people and is a problem in settings like nursing homes where it can spread pretty rapidly through the resident population in some cases. It is often referred to as scabies.

Many dogs that are being bitten by fleas do not have fleas that can be found on an examination. This is especially true of dogs that are allergic to fleas. Why? Because the dogs are very very good at finding the flea and ingesting it. They know they are being bitten and they know where they are being bitten when they are sensitive to the bites. This is even more true in the case of cats, who are also equipped with a barbed tongue and extraordinarily flexible bodies to help in capturing the fleas. So I wouldn't rule out flea bites just because you can't find fleas. Many clients also say "If my house had fleas, I would know it" but they are wrong. Fleas like to live on pets if possible. They attack humans when their favorite targets are unavailable.

It wouldn't be possible to tell you whether sarcoptic mange, flea bites, or another problem is leading to the symptoms you are seeing but it would be a really good idea for your daughter to use Frontline (TM) to kill fleas (and possibly even sarcoptic mange mites) that MIGHT be infesting her dog. People seem to have a hard time believing that their pet might have fleas even if they can't find them but it is true.

If you continue to have problems with the rash it would be a good idea to get your doctor to recheck you, too. (which I'm sure you have probably already done!)

Mike Richards, DVM

Zoonotic or not- human liver infection - cat blamed

Q: Dear Dr. Mike, If you can help me solve a big puzzle, it would be tremenduously helpful. My father was recently diagnosed with serious liver infections, and according to the MD, the bacteria came from an animal. They immediately pointed fingers at my 10-yr-old female cat "Donut". Donut is strictly indoor and quite health, despite occasional diahhreas. What are the chances of Donut transmitting bacteria to my father's liver, especially that my father has very little contact with Donut. My father rarely cleans Donut's litter box or plays with her. Is Donut's diahhrea an indication that she might have some potentially zoonotic virus?

Due to the seriousness of my father's liver infection, I'm forced to get rid of Donut in a few days, which I hate to do. Being an old cat, nobody wants to adopt her. This basically means that Donut will be left at the animal shelter for a week and then put to sleep - this really breaks my heart. So, I need to prove that Donut is not the cause of his liver infection as soon as possible. How can I do that? Regards, Diana


I would be very surprised if this parasite infection was from your cat, even if it is toxoplasmosis or giardia, neither of which seems very likely with the history given. As Michal has pointed out already, it is not possible to give you much more information than this without knowing the diagnosis.

Mike Richards, DVM

Transmission of Zoonotic disease..feline - continued

Q: Dr. Richards,

Thank you for responding to my inquiry regarding the transmission of zoonotic diseases from cat to human. According to lab tests sent out by my vet, my cat came up negative for Toxoplasmosis and Giardia.

I spoke to my father over long-distance phone, and he (prob. with the opinion of the doctor) insists that his animal virus came from the cat. They believe that perhaps the cat sneezed on him and transmitted the virus to him. Is that possible? Can any cat virus transmit through the air? What virus would that be? Sounds rediculous to me! Also, what are the chances of my cat catching any virus when she's strictly an indoor cat and our house is definitely clean? Even now the cat looks as healthy as ever! Could she carry some kind of virus harmful to us but has no effect on her?

I'll send you my father's parasite analysis report as soon as it becomes available to me.

Thanks for your time.

Regards, Diana

A: Diana-

It is not possible for me to say with certainty that your father's doctors are wrong but it is highly likely that they are. I have researched several databases for viral infections that can be transmitted from cats to humans and have not found evidence of any besides rabies at this time.

There is a rickettsial disease, Rochalimaea henselae (which used to be called Bartonella henselae) that causes cat scratch fever. That doesn't normally cause liver disease but I am not sure it couldn't.

Some physicians have expressed concerns about feline parvovirus infections, feline leukemia virus infections, feline immunodeficiency virus infections and coxsackievirus infections from cats but none of these viruses have been demonstrated to be zoonotic to the best of my knowledge.

When you have the report from the doctor's with the organism's name that they suspect is the problem I will be glad to try to figure out if there is evidence of it being a zoonotic disease for you.

Mike Richards, DVM

Asthma, Cat Allergy and Lots of Cats

Q: I am trying to help my sister-in-law who has asthma. She is allergic to cats on top of this all. She is trying to avoid having to go to steroids herself and yet spends the days wheezing when home and inhaling things to keep air passages open. She married my brother a few years ago. He lives in downtown Phoenix and had been feeding neighborhood strays for years. He had come to know that there was leukemia on the property and that every cat who comes and stays will eventually die of it. He rescued and bottle fed many kittens and now there are two new kittens. He spays cats when he can catch them and has money on the same day. Some are too wild to catch easily. His wife finally said that the cats could not come into the house and so they opened the basement for them. The cats have found passages up inside the walls of all of the floors of the house and, hopefully, are coming back down to the basement or outside to go to the bathroom. I have not visited in a year. I fear (having lost adult friends to asthma deaths) that I will lose this most wonderful of sister-in-laws to these cats. I know that my brother feels like the parent of the rescued babies and feels that he is running a Hermitage for dying cats (tho' it all seems very Catch-22 to me) and he is almost Hindu in his inability to put them to sleep or to do anything about them, other than to feed and water them and sometimes play with them. His wife loves cats too and loves my brother dearly and so, the family feels that we must come up with outside answers to this dilemma. Do you have any suggestions or some thing that I could tell my brother? I will ask him to come to your page and read any answer that you could give us.

Thank-you, April who loves her brother and his wife....

A: April- It is not easy to change people's behaviors unless they either want to change them or see the need to change them. This is a particularly tough situation when seeing the need may come too late. My limited understanding of asthma leads me to believe that a severe attack such as you describe is possible and that your sister-in-law actually could die in this situation. But she and your brother have to decide to deal with this situation themselves.

The way I see this, from your note, there are a couple of problems that need to be addressed. First, is your brother really doing these cats a favor - are they better off staying around his house than finding their own way in life? Who knows? My personal opinion is that it is much more responsible to keep one or two cats and care for them well than to keep a dozen and let them develop feline leukemia and become chronically ill and then die. I know for a fact, from numerous conversations with people in similar circumstances, that this is not the opinion of people who collect large numbers of cats or dogs even if they can only provide minimal care. They truly believe they are helping more than hurting. Euthanasia is usually not an acceptable option and discussions along this line are usually fruitless. This belief in life at all costs is like a religious faith and it is as resistant to logical discussion. I suspect that it is necessary to come to a compromise that does not involve euthanasia.

The second problem is the inability to keep the cats out of the house, even though it places your sister-in-law in jeopardy. This situation could be resolved by providing the cats with their own building, such as one of the portable yard buildings sold most places, and then thoroughly blocking entrances to the house. This would be much better for your sister-in-law. The dander concentration in an enclosed space is usually much worse than it is outdoors.

Your brother might even consider the option of spaying the cats and letting them stay outside and establish a territory. This would keep the number of new cats to a minimum and it seems reasonable safe to do this in Arizona, at least from a climate standpoint. Most cats are pretty resistant to heat related problems. One problem with this approach is that the cats will be able to spread the leukemia to other cats in the neighborhood. Another ethical problem.

Your sister-in-law may want to discuss this whole situation carefully with the physician treating her asthma. Perhaps he or she will have some advice on living with this circumstance. Wetting the cats thoroughly with water once or twice a week will keep the dander down and can help with allergies quite a bit but requires cooperation on the part of the cats.

If your brother would consent to it, there is a chance that psychiatric care might help. I know that sounds sort of radical and may not be financially feasible but animal collecting is beginning to be viewed as a sort of compulsive behavior and it might actually help a lot to talk to a trained therapist.

I am not sure if any of this is advice you will find practical to use in this situation. This is a surprisingly common situation.. Some people endanger their families and some people endanger themselves but a lot of people create situations in which their behaviors place someone at risk and often seem to be unwilling or unable to stop. It happens when people keep overly aggressive dogs, when they collect large numbers of cats and keep them in unhealthy situations and it happens when allergies or asthma produce a risk of death from a pet and people choose to keep them, anyway. I wish I had an easy way to help people see the best path to take in situations like this but it is different for every person or family.

Mike Richards, DVM

Michal Response: I'm going to worry more for your sister-in-law then for your brother's feelings in this case. Allergies certainly contribute to chronic pulmonary disease. Acute Asthma attacks certainly can kill. Bottom line - keep the cats in the house..shorten wife's life. With lung disease - you can feel like your breathing through a pillow most of the time..then it gets worse.

I am also aware of how difficult it is to change destructive behaviors.

Perhaps the family can help your brother build an outside kennel for his cats. A small building for shelter and a covered fenced area connected - with climbing material and perches..think small zoo. If the family pools its resources, the cost could be kept down. Any carpenters in the family?

Michael Lebowitz, M.D., Professor of Medicine and Epidemiology at the University of Arizona, Tucson, has done studies on the role of allergies and lung disease. Perhaps he could provide you with more information.

This is a new study - a different treatment for cat allergy. The Lung Association any be able to get it for you. *"Treatment of Cat Allergy with T cell Reactive Peptides." Philip S. Norman, et al. Am J Respir Crit Care Med 1996;154:1623-1628.

The American Lung association has a very good web site.. - or you can call 1-800-LUNG-USA.

Please don't waste time arguing - go after whatever aspect of this situation you can change.

Zoonotic index


Michael Richards, D.V.M. co-owns a small animal general veterinary practice in rural tidewater Virginia. Dr. Richards graduated from Iowa State University's College of Veterinary Medicine in 1979, and has been in private practice ever since. Dr. Richards has been the director of the PetCare Forum...