Giardia is an intestinal parasite responsible for many ailments in our dogs: let's look at how to identify it and beat it, with the help of an expert.
It is called giardia lamblia and it is an intestinal parasitic infection that can affect dogs, found with increasing frequency both in rural and urban settings. In kennels or breeding facilities, this parasite often causes full-blown outbreaks that are difficult to eradicate.
"Giardia is usually identified by the attending vet during the faecal examination routinely carried out in puppies and in cases of persistent diarrhoea in adult dogs," explains Dr Valentina Chiapatti, veterinary surgeon. The parasite causes episodes of foul-smelling, loose stools and, particularly in young animals, failure to thrive or weight loss.
"In dogs, giardiasis – the disease itself – should be suspected when there is a combination of intermittent diarrhoea, steatorrhoea (presence of fat in the stools) and weight loss despite a normal appetite," the vet continues.
Very prevalent in metropolitan areas too, especially in the warmer months when dogs go out more often and come into contact with one another, giardia is a parasite that can also be transmitted to humans. "In both humans and dogs, fortunately, giardia is often well tolerated and asymptomatic," Valentina Chiapatti continues. Giardiasis manifests in only 10% of infected individuals.
The cystic forms (oocysts) of giardia are shed intermittently in the faeces, where they survive for a long time and can contaminate soil, water and food. The cysts are ovoid, and as few as 10 are enough to cause the infection, which colonises the small intestine and, less commonly, the large intestine as well. If the infestation is massive, it quickly becomes symptomatic. The protozoa adhere to the surface of the intestinal mucosa without penetrating it, interfering with the physiological mechanisms of absorption. At this point they reproduce, and the eggs, shed again in the faeces, restart the cycle. Infested individuals (symptomatic or asymptomatic) shed a large number of cysts in their faeces – up to one million per gram of faeces – for several months.
It is worth knowing that this parasite attacks puppies more often because their immune systems are not yet fully developed. Establishing the presence of giardia requires only a simple faecal examination. A word of caution, however: "Because the shedding of the parasite occurs intermittently, if there is any doubt it is advisable to repeat the faecal examination on different days," explains Dr Chiapatti. "Usually the vet will ask for 3 stool samples collected on consecutive days and kept refrigerated in order to carry out the correct examination."
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Once it has been established that a dog has giardia, specific drugs exist to eradicate it. In addition to treating the dog, it is important to also decontaminate the environment to prevent reinfection of the same animal or of dogs living with it. "For environmental decontamination, strongly recommended when an infested animal is present alongside other at-risk individuals, several options are available," explains Valentina Chiapatti on her blog Amica Veterinaria. "A solution of gaseous ozone dissolved in water (the treatment is effective at a concentration of 0.3 mg/l for 2 minutes); ammonia (to inactivate oocysts, a 5 per cent solution is required for 20 minutes) or disinfectants based on 4-chloro-M-cresol."
Unfortunately, as far as outdoor environments are concerned, there are no methods for decontaminating gardens and yards that are not harmful to the environment and to the dog itself. The only measure that can be taken, beyond promptly removing faeces, is to keep grass well mown at all times, since giardia cysts are sensitive to dryness and direct sunlight.
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Precisely because of its characteristics, giardia is a parasite that tends to recur, especially during the warmer months. In cases of recurring giardia it is better, in any case, to treat only animals showing symptoms, unless the purpose of the treatment is to reduce environmental contamination (in breeding facilities, for example).
It is important to accompany both the start and the end of antiparasitic treatment with bathing the dog using specific shampoos and, where possible, to remove the animal from the infested environment – perhaps keeping it indoors rather than in the garden – or to avoid letting it frequent dog parks or areas where infection may have occurred.
"It is also advisable," concludes Dr Chiapatti, "to remove faeces from the garden or yard promptly, because the cysts of this parasite are already infective as soon as they are passed, and to prevent the dog from eating its own faeces or those of other dogs." Specific products exist that, by giving faeces a repellent smell and taste, will deter the little culprit from this unwanted behaviour.