Coccidia at 400%

Coccidia in Puppies and Kittens – Treatment and Prevention

Almost every dog breeder I know has encountered the nasty organism known as Coccidia at one time or another. Purchasing dogs from another breeder is often the most common route of infection, and always makes for a wonderful ‘bonus’ gift (“Oh look, the new puppy just sprayed explosive diarrhea all over the wall!” is a cry too commonly heard just after you let the little darling out of their crate for the first time). For all types of dogs, Coccidia can be picked up in a myriad of ways, in particular from dog parks or show sites – any place where your dogs can encounter cysts shed by other infected dogs.


In simple terms, Coccidia is:

Coccidia (Coccidiasina) is a subclass of microscopic, spore-forming, single-celled obligate intracellular parasites belonging to the apicomplexan class Conoidasida.[1] Obligate intracellular parasites means that they must live and reproduce within an animal cell. Coccidian parasites infect the intestinal tracts of animals,[2] and are the largest group of apicomplexan protozoa. Infection with these parasites is known as coccidiosis.

Wikipedia and the CDC (source)

It’s important to remember that there are a wide class of protozoans which fall under the heading of ‘Coccidia’, with varying symptoms and degrees of virulence. In some cases of Coccidia, puppies or kittens experience only mild, self limiting diarrhea that clears up rapidly without any treatment.  More serious forms of infection can progress to bloody diarrhea, dehydration, abdominal distress, and vomiting, and in some extreme cases, even to death. Severe infestations can also cause small tumors within the intestinal walls.

Older, previously infected dogs can suffer from a condition referred to as ‘Nervous Coccidiosis’. More commonly diagnosed in Calves, Nervous Cocci (as it is called in the dairy industry) affects the central nervous system (although the exact method of  pathogenic mechanism is still unkown).

In calves,

“Clinical signs of nervous coccidiosis  vary in both severity and frequency, and range from minor muscular incoordination, twitching, and loss of balance to intermittent or continuous seizures.”

Iowa Beef Center

Similar symptoms have been reported in dogs. I have noticed first hand that a larger than normal number of rescued dogs who have come out of puppy mill or mass breeding situations seem to exhibit these neurological symptoms. This has always been assumed to be due either to developmental distress, or perhaps to a higher than usual incidence of epilepsy and other seizure disorders, but I now wonder if it’s more indicative of non treated Coccidia in large scale breeding situations.

The severity of the symptoms in a Coccidia infestation depends on the ability of the protozoan to replicate – the faster they do so, the more virulent and life threatening the symptoms. As the Coccidian parasites replicate in the intestinal wall, they eventually rupture the cells of the intestinal lining, which leads to blood in the stool and progressively to anemia. The pain and distress cause straining and anorexia in infected animals, along with the other symptoms mentioned above.

The microscopic size of Coccidia Oocysts can make definitive diagnosis extremely difficult, and standard testing for parasites often misses them. In these cases, if Veterinarians, breeders or owners rely on these false negatives to delay beginning of treatment, the infestation has the opportunity to progress rapidly into a more serious stage. Complicating matters, the Oocysts can exist not only in faeces, but also as microscopic muscle cysts in the tissue of the infected animal.

Coccidia is opportunistic – it affects animals during times of stress and dietary change, and during weaning and re homing in particular.

Breeders can confront and stave off Coccidia in three ways:  first, by weaning onto a diet which causes as little digestive upset as possible;  second, by treatment with a preventative that has the potential to actually eradicate Coccidia within the host animal; third, by clean up of environmental surroundings using disinfecting methods able to treat Coccidia Oocysts. Pet owners can’t control how their puppy or kitten was weaned, but they can still follow some of these steps.

Traditionally, Coccidia has been treated post infection using sulfadimethoxine drugs (Albon, most commonly). Treatment is lengthy (5 – 7 days), and the potential side effects include:

anemia, loss of appetite, vomiting or diarrhea, joint inflammation, kidney damage, and skin rash.

Fairly serious side effects, for puppies or kittens who are already experiencing diarrhea and loss of appetite.  There’s also the issue that Albon is used to treat, not prevent – it does not stop infections from occurring, and it does not eradicate the protozoa from the infected puppy or kitten’s system.

A far better solution is to prevent and pre treat with Baycox, a Toltrazuril based drug made by Bayer Animal Health.

From the Bayer Animal Health site:

 Baycox is effective in one dose because it attacks all stages of the parasite in the animal.

Toltrazuril, the active constituent of Baycox®, is active against all intracellular stages of coccidia. It interferes with the multiplication process and the energy pathways of the parasite. Baycox® Piglet treats and prevents clinical disease while allowing immunity to develop against coccidia.

Baycox acts in two ways:  by suppressing oocyst excretion and by preventing the shedding of oocysts.  To be most effective, it must given before a puppy or kitten shows clinical signs of Coccidia – ie;  before the infected animal has diarrhea with oocysts in their feces.  Baycox can still be given as a treatment after infection, as it will help to lessen length and severity of the diarrhea by stopping the life cyle of coccidia in the small intestine.

Dr. Bruce Kilmer, DVM, of Bayer Canada, explains the action of Baycox on Coccidia, and the suggested mode of treatment with it:

Baycox is a triazine derivative. The drug active is toltrazuril, which has a cidal mode of action on protozoan. The toltrazuril will kill all single cell stages of coccidiosis. Once an animal has diarrhea and you can find oocysts on fecals, the drug can not penetrate the oocysts so technically it is too late to treat. In the actual clinical cases, treatment is still worthwhile to shorten the length and severity of the diarrhea as there is still development of the life cycle in the small intestine that will be controlled.

The idea is to dose the cat before there are clinical signs. For example, the normal situation would be a cattery having regular problems with coccidiosis in young kittens. The kittens normally would break with diarrhea at about 5 weeks of age. The treatment would be given around day 28, killing the early stages of the protozoa and preventing clinical disease. You will not have the history on a rescue cat so treatment would be best at the earliest hint of an outbreak and then repeat treatment in 7 days.

Baycox treatment will not cause sloughing of the intestinal epithelial cells. The coccidiosis does a fine job of that on its own. We have electron micrograph studies of sections of intestine 24 hours post treatment with Baycox. The intestinal cells remain intact and functional while the single cell stages of the cocci are dead, as evidenced by staining techniques. because Baycox is cidal, the kitten does not have to depend on its immune system to eliminate the cocci as what would occur with a static drug like sulfadimethoxine.

Remember that Baycox should be given during the preclinical stage .

Baycox is available in Canada, although it is ‘off label’ for puppies and kittens. An agricultural veterinarian may be willing to dispense it to you, but it is a regulated drug, and there is an enormous amount of paperwork required, along with stringent recording guidelines on administered doses of the drug.

In the USA, Baycox is not available at all at this time from Veterinary sources, although your vet CAN contact Bayer Canada and request to import the drug for non clinical testing. More information on this importation process can be found at:

The simplest way to acquire Baycox is to order it from Vet Products Direct – they have the lowest price I’ve been able to find, and their shipping is very reasonable. Just search “Baycox piglets” – you need to purchase the 5% Piglet formulation. DO NOT ORDER THE 2.5% Poultry Solution! It is meant to be diluted in water, and will cause distress and immediate vomiting if given by mouth.

By the way, I’m not compensated for recommending them – I just appreciate that they didn’t try to screw me on shipping, unlike some of the other companies I contacted (one of which wanted $200 to ship 200 ml of Baycox to Canada!).

Treating puppies and kittens with Baycox at four weeks, then again at six and eight weeks for one single dose is effective against all but the most aggressive forms of Coccidia.  Commonly accepted dosage information for puppies and kittens is:

Dosage advocated by Dr. Kilmer from Bayer (0.18 ml per lb of body weight) may be too high for young kittens (and puppies). The dosage that most breeders have apparently been using for some time with good results is about half that (0.10 per lb of body weight)

It is worth noting that almost all puppies and kittens find Baycox to be the most foul tasting substance they have ever encountered. They will routinely foam at the mouth after it has been given, shaking their heads wildly from side to side to escape the taste. Some breeders have found that following up a dose of Baycox with a spoonful of Carnation sweetened milk helps to alleviate the taste, and to lessen the harsh pH of the drug.

An interesting side note about Baycox – experimental studies have shown that it is also effective in treatment and eradication of Neospora Caninum (a similar parasite which once killed, with no notice or symptoms, one of my four week old puppies). You can read the entire article here.

In addition to treatment, environmental clean up is essential, although not easy. Bleach will not kill Coccidia, and neither will most commonly used disinfecting agents such as Novasan or Quatt. Steam cleaning, burning and 10% ammonia are the only truly effective agents able to kill Coccidia oocysts. Scoop your yard, dispose of feces, wash blankets, beds, whelping boxes and bedding with ammonia, and steam clean all carpeted areas and upholstered furniture.  Some particularly diligent breeders have replaced any grassy areas with concrete, brick or patio stones, which they then spray weekly with a 10% ammonia solution. Be careful not to combine ammonia with any other cleansers or deodorizers (bleach, in particular) – the resulting gas can be deadly to people and pets.

For breeders, alleviating stress during weaning is another way to stave off Coccidia. I wean directly on to finely ground, commercially made raw, mixed with raw goat’s milk. I make it into a slurry, and serve just slightly warmed. Feeding puppies this from their very first meal has helped to alleviate any ‘weaning runs’ outbreaks in my puppies. Additionally, starting puppies on to raw mimics the way dams instinctively wean by regurgitating food for puppies to eat (and it’s a lot less gross).

Keeping growing puppies and dogs on raw is another tool in the arsenal we can use to prevent active outbreaks of Coccidia, alongside modern drugs like Baycox. In time, we might be able to drop it from its current position in the top five most commonly found parasitic infections in pets.

Disclaimer: I am not a veterinarian, and this article is not intended to replace veterinary diagnosis or treatment. If you have a puppy or kitten who is ill, please take it to your vet for treatment IMMEDIATELY.

9 replies
  1. Dinsdale
    Dinsdale says:

    Great post! I am a HUGE Baycox fan after having dealt with coccidia for years. My vet introduced me to Baycox just over a year ago and I am thrilled with it. So nice not to deal with upset tummies and the MESS of pups suffering from coccidia. Since introducing to my pups not one owner has had to deal with it after taking their new pup home, such a relief.

  2. Dan M Vickers
    Dan M Vickers says:

    I am using bay Cox I have the off brand too hope it works from horseprerace lots cheaper. I gave it to my yorkie pups at 5 days old then twice a week now they are four weeks old eating I’m giving them the bay Cox brand now I hope this stuff works.I have Marquis I will give them that at 6 weeks old don’t know if its is safe to use earlier they say you can. I think the bay Cox is safer at younger age.

    • bmrktadmin
      bmrktadmin says:

      Baycox is actually very alkaline. But, if you dilute it you invalidate the dosage. The best recommendation is to give them a bit of carnation milk immediately after dosing them. Apparently, this counteracts the taste and the sensation.

  3. jack
    jack says:

    Does anyone. Know how soon after the first does of baycox I can give another does as they still are looking sorrowful they are 6weeks old and had there girst dose 5 days ago
    Found your blog brilliant thanks tells you more than English vets do!!!! Thanks


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