Dog Parasites and Parasite transmitted Disease



Q: Doctor Mike: Please give me as much information as possible as to the cause and treatment of coccidia in puppies. Also, are litter mates likely to contract this condition? Is this condition contagious to other animals, such as kittens, birds, rabbits and others? Are there any precautions to be taken when the contagious animals have been in contact with these other animals? Thanks you so much for your continuing service in answering our questions as your information has proven to be very useful to us. Thanks again and have a great day. Connie    

A: Constance-

Coccidia are a group of protozoan parasites that are extremely common and which infect a wide number of animal species, including dogs, cats, horses, cattle, goats, sheep and chickens --- and many other species of animals, as well.  The groups of coccidians that infect pets include Eimeria, Isospora, Hammondia, Toxoplasma and Neospora.  Of these, the two that are usually referred to as "coccidia" infections are Eimeria and Isospora infections and the rest are generally identified by name, as they are more complex parasites and cause specific disease problems. Eimeria species are more commonly involved in infections in cattle, sheep, horses, etc. and Isospora species are most commonly involved in infection in dogs and cats. So for the purpose of the rest of this note, the enteric (gastrointestinal) forms of Isospora are what will be covered.

The first thing that has to be considered is that coccidosis is very common. It is likely that 30 to 50% of puppies have coccidia in their stools at some time during their first few months of life. These may be coccidia from another species that the puppy or kitten has in the digestive tract due to ingestion of stool, such as rabbit feces, squirrel feces or cat feces (in the case of puppies).  If this is the case it is unlikely that the puppy or kitten will actually have any clinical disease as a result of ingesting the coccidia. In other cases, a puppy or kitten becomes infected with coccidiosis, produces lots of oocysts of coccidia but never has clinical signs of disease such as diarrhea, loss of appetite, vomiting or failure to thrive. These pets may never show any clinical signs and without signs it is questionable whether they should be treated or not, although I think that almost all veterinary practitioners go ahead and treat for the infection. Isospora species can also be transmitted through ingestion of intermediate hosts, such as infected mice.

Isospora species that affect dogs include Isospora canis, I. ohioensis, I. neorivolta and I. burrowsi.  The species that affect cats include Isospora felis and Isospora rivolta. These coccidia tend to be pretty species specific, so infection of a puppy or kitten is not thought to be a risk to humans and puppies are not a risk to cats or infected kittens a risk to dogs. It is very likely that if one puppy in a litter has coccidiosis that all puppies are affected. It is extremely difficult to prevent coccidia infections, especially in group situations, so puppies coming from a breeder with coccidia is not an indication of poor sanitation or poor health care practices. It is simply a very common problem.

Coccidia spread when oocysts are shed in the stool of infected pets and then the oocysts are consumed later by another susceptible dog or cat. Since incredible numbers of oocysts are shed from infected pets, the environmental contamination with coccidia oocysts is severe. Puppies and kittens often show signs of illness, usually watery diarrhea, before there are oocysts in their stools, so it sometimes takes several fecal samples to know if a puppy or kitten is infected. In addition, lots of dogs, cats, puppies and kittens are infected and are shedding oocysts despite having no clinical signs of infection.

Coccidia are easy to find using standard fecal floatation methods for fecal exams and are often present in sufficient numbers to show up if a small amount of stool is smeared on a glass slide, mixed with a small amount of saline and examined.

When Isospora species cause disease the most common form is watery diarrhea that is very profuse. Many kittens and puppies seem to just leak watery stools as if they have no control at all over their bowel movements, while others have a more "normal" diarrhea. Without treatment, the diarrhea might last for several weeks. With treatment the diarrhea might last several weeks, too --- but it does seem to cut down some on the duration of the diarrhea to treat affected puppies and kittens. The most commonly used medications are sulfonamide antiseptics, such as sulfadimethoxine (Albon Rx, Bactrovet Rx) given at 55mg/kg of body weight initially and then 27.5mg/kg per day for 4 to 7 days. The medication should be given until two days after symptoms of illness have disappeared. Lots of vets substitute trimethoprim/sulfa combination medications (Ditrim Rx, Tribrissen Rx, Bactrim RX) for this sulfadimethoxine, using a dosage of 15mg/lb of the combined product and this seems to work, too. While it is probably impossible to kill all the coccidia in a puppy with clinical disease using medications, it may help reduce the numbers of organisms that littermates and housemates are subjected to and to shorten the duration of clinical signs.

In some cases it does seem like there is resistance to the sulfanomides. I am not sure if this is actually the case, since it is difficult to tell if the medication is working in the first place. However, if this is suspected, alternative medications include ampolium (Corid Rx) and furozolidin (Furoxone Rx).

General cleanliness does not ensure that infections will not occur, but removal of contaminated stool reduces the potential for infection. The oocysts are supposed to be pretty resistant to most disinfectants and things like steam cleaning or flame guns may be necessary to actually kill the oocysts, which is impractical for most situations.  Keeping access to mice down (especially for cats) is also a good idea.

So the direct answers to your questions are that most of the time all littermates are infected. It is not likely that other species will be affected. The organism is spread in the stool, so keeping non-infected pets away from the stool of infected pets is helpful but if they share a common environment it is highly likely that infection will occur. The infection may or may not cause clinical disease and treatment is generally considered to be necessary only for pets showing clinical signs.

I hope this information is helpful.

Mike Richards, DVM   


Q: I know by reading some that you are not in favor of raw meat diets. Well I've fed for four years and two puppies from two different litters, one being a runt have got Cryptosporidiosis. They are on tylosin for 28 days. How do I get rid of the irritated bowel syndrome?? Tonight I am cooking brown rice and defatted chicken with some peas. I did give them some yogurt and cottage cheese which did not seem to help. My Vets have only seen one case  thirteen years ago so they are not experts. I had the one who seems to have a almost decent stool and then another not real good on a low dose of Flaggell but have taken him off. I want to get the stools good. Will I be able to clear this condition in 28 days.????? Another new frontier in breeding purebred dogs. You know we try our best to do the best for the animals and it back firers. Anxiously awaiting your kind reply, Gale  

A: Gale-

In most of the literature references about cryptosporidiosis there is resolution of the clinical signs with effective therapy. This condition is caused by a protozoan parasite of the Cryptosporidium family.

Tylosin is one of the recommended therapies, along with clindamycin (Antirobe Rx), azithromycin (Zithromax Rx,  7 to 15mg/kg every 12 hours for 7 days), and paromomycin (this should be a last resort because it has been reported to cause kidney damage in cats and I don't know if this is a potential problem in dogs).  Hopefully, the tylosin is already working. If not, one of the other medications might help.

Cryptosporidiosis is considered to be a zoonotic disease (can be transmitted to humans), so take precautions to prevent getting it, like washing hands well, wearing latex or vinyl gloves when cleaning up diarrhea and other similar preventative measures. This is mostly a problem in immunocompromised humans, so don't get too excited if you feel you may have been exposed.  Do report any symptoms, such as diarrhea, to your doctor, though.

I am hopeful that you are seeing some improvement at this time. If not, it would be best to let your vet know and perhaps to try one of the other medications to see they help more with this problem.

Mike Richards, DVM

Cheyletiella Mites

Q: Dear Dr Michael: Thanks for all your help so far. Scrumpy has been found to have Cheyletiella mites and also, although later Ringworm. She's been on an oral treatment of 0.4 ml Doramectin for about a month. She was treated with Frontline about a week ago. She's been treated for the Ringworm with tablets and iodine baths, and as far as we can tell, that has gone. However, the mites are still with us, and she is still getting red patches on her skin. All her undercoat has gone (she's a labrador with a proper double coat - or was). It seems to me that with all this treatment she should be getting better, and I wondered if you had any comments that you could help me with?

She is otherwise feeling well and full of energy.

Regards, Elizabeth

A: Elizabeth-

Cheyletiella mites are supposed to be pretty easy to kill. There is at least one published study, in which ivermectin (Ivomec 1%) was used by giving three doses, at 21 day intervals, and it cleared the mites from all twenty of the dogs in the study.  There is also a report on the use of fipronil spray (Frontline Spray Rx) once a month to kill cheyletiella mites and all of the animals in this study were cleared after the initial treatment.  Selamectin ( Revolution Rx) is also reported to kill these mites very effectively and is also meant for once a month use.  Cheyletiella mites can live off of the dog for several days, so it is generally recommended to treat the house, kennel or other premises in which the dogs reside, but this may not be necessary when using fipronil or selamectin, since they have a continuous action when used monthly.  For mite infestations, Frontline Spray works better than the Frontline Topspot (tm), which is the topical product applied as a "spot on".

Some dogs are hypersensitive to the mites, developing an allergy type response to the mite. The itching from this condition may not resolve for several weeks after the mites disappear.

It is possible for dogs to have multiple mite infestations, so an underlying problem with sarcoptic mange might be present, but the same treatments usually work for this mite, although fipronil applied at normal dosages may not be effective.  It is also fairly common for secondary bacterial infections to set in when mites have been present and this won't clear up until it is treated, as well. This also happens with Malassezia yeast infections, although some of the ringworm medications work well to control this, too. Another possibility is an underlying allergic condition. Atopy  (inhaled allergies) seems common in Labs in our area. Fleas should be carefully controlled in any dog or cat that has skin disease, so keeping after good flea control is also important.

If this problem persists, it may be worthwhile to ask your vet for referral to a veterinary dermatologist or to consider further diagnostic work, such as skin biopsy.

Good luck with this. I'm hoping it was a sensitivity problem and that you are seeing improvement at this point.

Mike Richards, DVM

Cheyletiella Species Mites

Q: Dear Dr. Richards,

I will be very happy if you can help me. One of my female brings me after she has been covered mites, if I am not wrong they are "cheletelya parasiti vorax" as we say in French. A few years ago one my female had these mites and my friend of Canada send my a shampoo in two wasking it disappeared. But now he stops breeding, I am unable to get the name of these shampoo. Now I have myself about 60 bites all ower my body except in the face, but arms, shoulders, legs have small bottoms. I get mad with theses itches. Please could you help me telling what I can make to avoid these little mites. Thank you. Kind regards from Switzerland. M.  

A: M.-

Cheyletiella species mites are usually pretty easy to kill using products that will kill fleas. It is necessary to use a shampoo or topical product several times at weekly intervals to be sure that the mites are killed. Since Cheyletiella mites can live in the environment for up to ten days, it is necessary to treat the house to keep the mites from returning. Standard flea control treatments for the house will usually work to kill the mites. It may be necessary to treat the house more than once in some cases. If this approach doesn't work, giving ivermectin orally at a dose rate of 200 to 300ug/kg three times at 14 day intervals will usually control the infestation.

If this is a dog, you might be dealing with sarcoptic mange. This will respond to topical medications in many cases, too. People can be affected by this mite and it does cause very severe itchiness in humans. We usually use ivermectin for this disease at the present time,  because it is easier for the clients and because it works well. Your vet can probably provide this medication after confirming the diagnosis.

I don't treat people, but it is my understanding that the itching can be relieved with medications, if you have contracted this mite. The infection is self-limiting in humans and will go away two or three weeks after you successfully rid the dogs of the infection and are not picking up more mites from them.

Hope this helps some.

Mike Richards, DVM  

Tick Control

Q: Dear Dr. Richards,

I so much appreciated your comprehensive reply to my questions of May 3rd that I sent an email to all the members (about 18 people) of both Schutzhund clubs to which I belong -- I hope it will result in at least a few new subscriptions for you.

Ursa does seem to have responded well to the antibiotics for the Ehrlichiosis, and, with my veterinarian's blessing, I worked her gently for the first time in weeks last night, and she showed no ill effects whatsoever. Hence, I am hopeful that this episode is forever behind us!!

However, I was really dumbfounded to discover at least 6 live ticks last night night after only a 21-day interval since the last time I applied Frontline. The package clearly says to use no more frequently than every 30-days; however, I dosed her again anyway figuring the possible ill effects of using the Frontline somewhat more often than recommended can't be any worse than the tick-borne diseases.

Is there a better alternative? Are you aware of any effective products which are safe to use in conjunction with the Frontline so that I don't have to use it more frequently than recommended? Are the "Preventic" (sp??) collars effective and safe to use with the Frontline? If you're not aware of other products which you feel good about recommending, would you (if it were your dog living in an area with a high density of ticks) do as I did and use the Frontline more frequently than recommended?

Thanks again & regards, Richard  

A: Richard-

We find that the Frontline Spray (Rx) works better for tick control than Frontline Topspot (Rx), the topical version, when applied according to the directions, including using 2 pumps of the spray per pound for medium to long haired dogs. It will usually last a month in this case. Fipronil, the active ingredient of these products, is pretty safe, but it is illegal to use an EPA approved product in a manner not in keeping with the package directions, so I don't think there are too many vets experimenting with closer intervals.

Preventic (Rx) collars, which use amitraz as the active ingredient, are very effective for 30 to 40 days for tick control. We would recommend a lot more of these collars except that they are toxic if ingested and they appear to taste good because we have treated at least five patients for toxicity from eating them. There has been at least one human poisoning from ingesting a collar, too. So now only recommend these collars for dogs who do not live with other dogs and who do not live with toddlers, the most likely age range human to eat the collar. These collars can be used at the same time as Frontline, if desired.  For dogs that have both ticks and fleas, that is necessary, since Preventic collars do not affect fleas.

Permethrin, which is the active ingredient of a number of products, including Control (tm), BioSpot (tm) and Defend (tm) is a very effective tick repellant and tick killer. It only lasts a couple of weeks, which used to be OK with Defend, since the label said it could be applied at two week intervals if necessary, but I have not read the labels on the other products to see what they say about this. It is OK to use a permethrin product and Topspot (Rx) at the same time. We recommend putting the permethrin product on in the middle of the month and the Topspot on in the beginning of the month, which has worked well for some of our patients who experience severe tick exposure.

Hope this helps. I'm sure Ursa would be glad to be rid of the ticks.

Mike Richards, DVM  

Imidocarb (Imizol Rx)

Imidocarb (Imizol Rx) has been approved in the United States for use in treating Babesia. It also appears to be effective for treating Ehrlichiosis when doxycycline is not effective. This is an injectable medication which must be administered by your veterinarian. The recommendation is to give two injections with a two week interval between them.  

The Difference Between Fleas and Lice

Q: If you could please send me some more information regarding lice it would be appreciated. Alecsis M  

A: Alecsis-

Lice are small light colored (white to cream colored) parasites. The lice themselves are visible to the naked eye but can be hard to find as they are pretty small. Examination of debris from the haircoat with a magnifying lens might help in identifying them. Their eggs (nits), which are attached to hair shafts, are often much easier to find than the lice themselves. The look like little white to yellow lumps on the hair and are often deposited along the whole length of hair shafts that have nits. They can infect both dogs and cats but are not commonly seen in veterinary practices in most of the U.S.  Lice are susceptible to many of the products that kill fleas but it may be necessary to clip mats from the haircoat and to use insecticidal products for several weeks (4 minimum) to totally eliminate the lice.

Fleas are larger, reddish-brown to brown to black parasites that are very mobile are often easy to find in the haircoat of pets that are infested with them -- but which can be present on the pet or in the environment without being easy to find due to the ability of pets to chew or sratch fleas out of their haircoat. The new flea products, Frontline (TM), Advantage (TM) and Program (TM) are all very effective in reducing flea populations in pets and it is finally possible to almost do away with this problem in most households.

Mike Richards, DVM


Q: Our Golden Retreiver has been diagnosed as having coccydia parasites as a result of a stool screening. We assume she picked this up from rabbit droppings. Is it transferrable to humans? We have a handicapped son, and she often licks his face, hands, etc. Are there any special precautions we should take?

A: Jerry - Coccidia are normally thought to be species specific, with the exception of Toxoplasmosis which is transmitted through contact with cat feces to people but is not a problem associated with dogs.

It would be a good idea to make sure your golden stays free of other intestinal parasites, especially roundworms as there are occasional reports of these being transmitted by dogs licking the faces of children. Use of one of the monthly heartworm medications that control roundworms may be appropriate.

Mike Richards, DVM    

Tick Removal

Q: Dr Mike, Ticks are very bad this year in Maine. If I find a tick on my dog and it is swollen, how do I remove it? I have heard that you don't want to "pull" it off because the head of the tick will be inbedded in the dog's skin causing infection or worse. How do you get a tick off, leaving it's head attached to it's body? Thank You - Deb.

A: Deb,

It is probably best to use one of the tick removal devices that are available now. Several are made and they each have advantages and disadvantages. There are ads for these in the dog magazines if your vet doesn't carry one. We have tried a couple of them and both were good, but neither one was perfect. A good forceps (tweezer) is OK, too. Grasp the tick as close to the head as possible and pull with an even force. If part of the tick is left in the dog it is not a total catastrophe. Just like a small splinter or anything else foreign in the body, the white blood cells will destroy and remaining tick parts. If you give in to the temptation to remove ticks by hand and won't use latex gloves or at least a tissue then be sure to wash your hands really well. There is no use in getting one of the tick-borne diseases yourself.

It is also OK to use a product like ProTicCall (TM), Defend (TM), Frontline (TM) or Frontline Topspot (TM) to kill the ticks and just wait for them to die.  There are a number of products available right now with concentrated permethrin, which is the tick killing ingredient in ProTicCall. These products say they last up to four weeks but our experience has been that they last about 2 weeks and are very effective for that length of time. Frontline is slow to kill ticks, taking up to 48 hours but is pretty effective.  Preventic (TM) tick collars also work well but it is very important that they are not ingested. In multiple dog households this can be a problem and I would worry if I had a toddler of the human variety, too. For a lot of people it is easier to use one of these products rather than doing daily tick search and removal.

Mike Richards, DVM  

Tick Removal II

Q: Dear Dr. Mike, Our dog had a tick attached to him that was very swollen. My son tried to get it out using a hot cigarette, but it only dug in farther. We tried getting it out with tweezers and it broke off and we could not get the head removed. Will the head fester out on its own or do we need to go to the vet and have it removed? I put peroxide on it to help against infection and plan on checking it daily. I would appreciate any info you can give me. Thank you, Donna

A: Donna- It is best to remove ticks with a forceps (tweezer) or tick removing tool (there are several of these on the market). If a portion of the tick is left in the skin it usually will not cause problems. Once in a while an itchy bump develops at the site but I have not seen major infection yet, at least not that I have recognized as being from a tick.

There are several good tick control products on the market now. Two topicals, ProTICall and Frontline work well against ticks for several weeks after an application and Preventic collars work pretty well, too. It might be better to use one of these products and keep the tick problem to a minimum.

Mike Richards, DVM  

Dealing with Ticks

Q: Dear Dr. Mike, We have a seven month old Border Collie, she recently got a tick above her left eye, I put vaseline on it and it died and I pulled it off. When we were recently at the Vet I asked her how to treat these she said to always bring the dog in. Now I am worried because she has a small scab were the tick was attached. Is there any home treatment for ticks? Also we live in a wooded area with deer and other wildlife, should I be overly concerned? S.

A: Where we live, if I told every client to bring their dog in for tick removal, that is all I would have time for during the day!

There are a number of ways to deal with ticks. The easiest solution is to use one of the tick killing products that keep them off and/or kill them if they attach. There are three very effective products that we use, fipronil (Frontline or Frontline Topspot, Rx), permethrin (ProTICall, Rx) and amitraz (Preventic collars, Rx).

Frontline kills fleas and ticks effectively. Tick control lasts for 2 weeks to a month. The product should only be applied on a monthly basis but can be used in conjunction with other products for tick control if necessary. It works very well for flea control, so if that is also a problem it may be a good first choice.

ProTICall is a concentrated permethrin topical for tick and flea control. It is a very effective tick control product but a less effective for flea control. It lasts 2 to 3 weeks but may be applied at 2 week intervals so it is possible to keep the problem under control continuously using this product.

Preventic collars are also pretty effective. They have the drawback of being toxic if ingested. This sounds like it wouldn't be a problem but dogs will eat these collars right off of another dog, for some reason. So we don't recommend them for multi-dog households, especially if one of the dogs is prone to playing with the other dog's collar or if one of the dogs chews things up frequently. They seem to last around 6 to 8 weeks in our practice area.

Ticks may be removed using one of the tick-pulling products or a forceps (tweezer). It is best not to touch the tick if possible due to the possibility of tick-borne diseases. If contact does occur, wash your hands thoroughly. There is a lot of fear of leaving part of the tick embedded in the dog when removing them but this rarely causes problems.

Ticks carry a number of diseases, some of which do have zoonotic potential (can be transmitted to people). It is best to use one of the products that kills the ticks continuously without much intervention on your part. The risk is not high but there is some risk for diseases such as Lyme disease, ehrlichiosis and Rocky Mountain spotted fever when ticks are brought into the household by a family pet.

Mike Richards, DVM  

Tick Control

Q: I live on Cape Cod and am going into my first full season with my golden retriever. My house borders conservation land and there is a pond about a quarter of a mile in. I need to protect my dog from ticks as I have already removed about 30 ticks in the last 3 weeks. She is very active and swims almost every day. I am reluctant to use chemicals on her but I really feel the need to do something to protect her. Are the products like biospot and defend safe? Also how well do they hold up in water. My dog is 2 years old and weighs about 70 pounds. The only other medication she takes is her heartworm pills. K.

A: We do not use Biospot but we have used a lot of Defend (now called ProTICall). I think that ProTICall causes itching at the site the product is applied often enough to be a minor concern with its use. It does wash off readily with soap and water so it isn't a big problem when it occurs. This product only seems to last a week or two when dogs spend a lot of time in the water. It seems to last 2 to 4 weeks in most dogs in our area on the average, though. Despite the minor problems with itchiness this is a very effective and reasonably safe tick control product.

We have used the collars produced just for tick control, containing amitraz (Preventic Rx). These work well but are toxic if the dog, or another dog, eats them. They seem to last about 4 to 6 weeks in our area and most dogs here do spend a lot of time in the water.

Fipronil (Frontline and Frontline Topspot Rx) seem to work well against both ticks and fleas for 3 to 4 weeks in dogs and the flea killing effect can last up to three months. In our area with the amount of water exposure we find that the Frontline spray lasts longer for tick control than Topspot does. It is safe to apply monthly, which would control most of the problem.

It is also acceptable for tick control to spray with a permethrin based spray prior to letting him out each day (or on arrival home). Most of the time this will control the ticks reasonably well, too.

Hope this helps.

Mike Richards, DVM  

Traveling - What About Fleas and Heartworms?

Q: Dear Dr. Mike,This June we are travelling across Canada, (from B.C. to Newfoundland), with our newfies as part of the Great Newfoundland Dog Trek.  The area of B.C. that we live in is free of fleas and heartworm, so we have never had to worry about treating or preventing these problems.  However, we will be travelling through areas that have these nasties, and we will be with over 100 other newfs from all over N. America.  Should we be considering some sort of preventative medications before we start or for while we're travelling?  Thank you in advance for your advice.

A: I definitely think that you should put your dogs on heartworm preventative if you are traveling through an area in which it occurs. The monthly heartworm medications do not need to be started in advance of the trip but flea medications will need to be started before you leave. The monthly heartworm medications are not timed-release or long acting medications. They work by killing all stages of the heartworm's life less than about 45 days of age. So the dog collects whatever heartworm larvae it is going to collect for a month, a pill is given and they are all killed. In our practice, the monthly medications seem to be more reliable than the daily pills. To use these, you should start after you have been traveling for 30 days, then use them for at least two months after you get back, to ensure that all larvae are killed. If it is a short trip, just give them when you get back and for two more months, to be really sure that all larvae are killed. If you elect to use daily heartworm medication you do need to start it right before you leave because it works a little differently. It can only kill one stage of the heartworm larvae's life, so it must be present in the body when the larvae gets to that age. So the daily pills would need to be given throughout the time of the trip and about a month to two months after you get back.

Flea prevention is a little more straightforward. The best flea medications for short term use during a trip would be fipronil (Frontline or Topspot, Rx) or imidacloprid (Advantage Rx). Fipronil will last up to three months with one application and imidacloprid lasts a month with one application. I am not sure of the availability of these medications in Canada but you probably have them, too. You just apply them right before you leave and then again if you are gone longer than the period they work for. Your vet will probably want to check your dogs to be sure that none have heartworms prior to dispensing heartworm medication unless he or she feels really certain that is not at all possible where you live. Dogs less than 6 months of age can not be checked for heartworms using the currently available tests, so they would be excluded from this decision. Hope that helps.

Mike Richards, DVM  

Flea Life Cycle

Understanding the life cycle of the flea is necessary in order to control it. The flea has several stages to its life cycle. Adult fleas spend most of their time on the dog or cat - they must be dislodged to leave since they will not do so voluntarily. Despite this, when the flea population on the dog becomes excessive humans tend to be an acceptable alternative to the flea. The average lifespan of an adult flea is probably about 6 weeks - but fleas can live as long as a year under certain conditions. A female flea can lay 20 to 28 eggs a day. She may lay several hundred eggs over her lifespan. These eggs fall off the pet and develop where they land. They are small and can even develop in the cracks in wood floors or other small crevices. A larvae hatches from the flea egg. It takes as few as 9 days to as long as 200 days to go through its growth stages. At this time is forms a pupae and waits for the right time to hatch. Fleas prefer temperatures of 65 to 80 degrees and humidity of 75 to 85 per cent. This range determines the period of time that fleas are a problem in your particular area. For some areas of the country, this is all year. In others, the flea season is relatively short. It is estimated that for every adult flea found on the pet, there are about 10 developing fleas in the pet's environment.

Flea eggs are pretty small and most people do not see them. The flea "dirt" associated with fleas is black in color and is actually flea feces. It tends to be a pretty uniform size with a sand like consistency if present in large quantities.

Michael  Richards, DVM  

Flea Control

Since we know that the flea lays her eggs on the pet and they fall off, it is obvious that they fall off where the pet goes. This means that you must treat your house if your pet comes inside. Many people resist doing this, explaining that they never see fleas in the house. The flea egg does not move and it is very hard to see. The flea larvae does not have legs so it has limited movement. The pupal stage of the flea does not move at all. It is not likely that you would be aware of immature fleas --- until they grow into adults. At this point you will be overwhelmed and the problem will be very hard to control. It is possible to kill the pre-adult stages of the flea in the house. Outside, the flea eggs fall off in areas where the pet does things that dislodge them, like jumping around, sitting and scratching, etc. If these areas are warm and moist throughout the day, the flea can reproduce there. It is not necessary to treat large expanses of lawn that dry out during the day -- concentrate on areas the dog spends time, that stay moist and warm. Make sure you treat around the doors in and out of the house, where your dog or cat is likely to be waiting around and where flea eggs are likely to drop off.

There are now several "once a month" flea control medications for pets. Lufenuron (Program - tm), makes control of preadult fleas easier than it has been in the past. This medication is approved for both dogs and cats. It is administered once a month and is active in the body for that entire time. At the present time there are no known side effects of the medication other than a small percentage of pets who are naseous after administration of the pill. It may be administered when other medications are being used. The pill does not affect adult fleas at all. Therefore it is important to start this pill before the flea season or to treat for adult fleas as necessary. There are also "once a month" adult flea control medications. Advantage (tm) and FrontLine (tm) are two new medications that provide long lasting adult flea control. Advantage works for about one month to kill fleas and FrontLine works for one month in cats and up to three months in dogs. These are very effective products. While these products may be combined with Program (tm), their ability to kill adult fleas effectively may make it un-necessary. There are many other products that will kill the fleas on the pet. Shampoos, powders, and sprays tend to kill only the fleas present on the pet at the time of application. Mousses (flea foams) and flea creme rinse products tend to have some residual effect. Dips, which are usually used as pour-on products, have a slighlty longer residual effect and are more likely to be associated with toxicity. Proban, an orally administered flea killing pill has short duration of action but is made to be given twice weekly. There are "spot on" products as well, which have may have a longer duration of action. However, all of these products are more toxic and/or less effective than FrontLine (tm) and Advantage (tm).

Treating the house should involve a two pronged approach. To kill the pre-adult fleas it is necessary to use methoprene (Precor). This can be done by using this product alone, or in combination sprays with an adult killing ingredient. The ingredients that kill preadult fleas are generally effective for 3 to 4 months, indoors. Killing adult fleas can be accomplished using any of the pyrethrins (tetramethrin, pyrethrin, permethrin, etc.), or an organophosphate. The adult flea killing ingredients do not have a residual effect and retreatment every 2 to 3 weeks until the fleas are gone is usually necessary. These products come in sprays and aerosols (foggers). It is very important to read the directions, figure out the square footage you are attempting to treat and use these products properly. Foggers generally are ineffective unless one is placed in each room, so small size foggers may be the most economical approach. An alternative to this approach is to use a sodium borate product for flea control - such as FleaBusters. Some people use diatomaceous earth (food grade) in the house to control fleas.

Flea treatment in the yard can be accomplished using one of the yard sprays specifically made for this purpose. There is a new approach, in which a nematode (worm) that lives on flea larvae is spread in the yard. This is non-toxic and appear to be effective. These worms are sold by various companies. One brand name is Interrupt, available through veterinarians. Remember, it is only necessary to treat areas which stay warm and moist. For some people this will be the whole yard. For others, treatment of much less than the whole yard will be effective.

Prior to this year (1996), we felt that effective flea control meant that you needed to treat the pet, the house and the yard. Not treating any one of these could lead to perpetual flea problems. It appears that FrontLine (tm), Advantage (tm) and Program (tm) may change that situation and allow control of fleas with treatment of the pet, only.

Flea control can be accomplished if you are careful to take a few steps to ensure that your plan works. Treat your pet with one of the new flea control products. If you elect to treat the house, to it right. Measure your house and figure out the square footage -- then apply a proper amount of flea control product. If you are using foggers, make sure that they will cover the area you anticipate -- don't expect them to treat two rooms by placing one in the hall, for instance. Get a fogger for each room. If you use a professional exterminator, make sure they use a product that kills preadult fleas as well as an adulticide. Pay them to come back in 2 weeks the first time, rather than waiting a month. Keep up the treatment until you see no fleas, then use the preadult products 2 or 3 times a year to keep the problem from coming back.

Fleas can be controlled. It can be expensive to take care of a flea infestation but it is usually cheaper than dealing with the complications to your pet's health that fleas can bring about.

Michael Richards, DVM


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...