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Dr. Hoshizaki: [It is] really a great honor to be here. Thank you for having me. Iím
really excited to talk about actually one of my favorite parasites. When they said,
ìWhat do you want to do for the conference?î I was like, ìGiardia. Thatís great!î So,
Iíll try to control my enthusiasm. I know you guys just had a big lunch, so hopefully
I can give you some of my zest. Without further ado ? weíve got a lot to cover ? letís take
a look at Giardia: For Shelter Staff and Veterinarians.
First of all, when I say the word Giardia what do you think of? What is the clinical
picture? What are you thinking of for humans or animals?
Audience: Diarrhea.
Dr. Hoshizaki: Iím sorry?
Audience: Diarrhea. Diarrhea.
Dr. Hoshizaki: Oh, yes. Yes. Iím like ìDiarrhea. Absolutely.î But, of course, thereís more
to it than just the clinical picture. What is Giardia in a grander scheme? Think about
that, and Iím going to ask the question again in 20 minutes. Hopefully we will have clarified
some issues.
Giardia is a protozoan parasite that lives in the small intestine and you can see here
[the] little teardrop shaped protozoa on the slide. As you guys already know, or many of
you know, diarrhea is what we think of ? so gastrointestinal disease in dogs, cats and
humans. This is a zoonotic disease, which affects humans and other animals. I just googled
ìGiardia Outbreak,î and look, I got one really close to here, really recently. Itís
an important zoonotic disease that affects humans and you are going to see it in the
news. Of course, in the shelter setting, where weíre thinking more about cats and dogs,
unfortunately, it is a very difficult disease to diagnose and to treat in that setting.
We have two varieties of Giardia, which we are going to think about. Weíre going to
think about the adults. These are the protozoa, which are in the small intestine. They are
the ones who are causing disease. One of the reasons why they are my favorite is because
I think they look like little smiley faces. I donít know. Iím not great with all of
the other eggs, but if I see a Giardia I know what it is. Itís smiling right back at me.
The other form of Giardia we think about is the cyst. These are ìeggs,î which are in
the environment, and these are what are infecting the other animals in the shelter. Coincidentally,
I kind of also think they look like little smiley faces. I donít know if anyone else
sees that.
In order to treat Giardia effectively in the shelter, we need to know a little bit about
its life cycle. Very simplistically, we begin with a cyst in the environment. Itís going
to infect our host, which is our cat. One way or another, this cat is going to ingest
the cyst and become infected. Once inside the cat, we are going to have the cyst mature
into the adult protozoa and itís going to make little friends. We going to cause disease
and weíre going to keep multiplying and producing more Giardia. At a certain point, weíre going
to start producing more cysts. Theyíre going to start reproducing, and theyíre going to
go out in the feces, in our diarrhea. So these cysts are going out, back into the environment,
and theyíre going to be able to infect more animals.
As weíve already mentioned, transmission is primarily what we call fecal-oral, or poop-to-mouth
in laymenís terms. Somehow these animals are eating things, which are contaminated
with feces. This can be through food, through water sources, and very importantly, in the
environment. I have a picture, there, of some puppies out in a play yard. They are going
to have cysts in the dirt. Itís going to be on the wire. Itís going to be on all the
food bowls, etcetera, and itís going to be on the equipment. If weíre moving things
between cages that could possibly be contaminated, thatís another great way to spread your cysts.
Also shown in this picture very well is [contamination] through fur and grooming. The cysts come out
in the diarrhea. Theyíre going to stay on the back ends. If dogs are walking in it,
it is going to be on their paws. If the cat goes around grooming itself, it is going to
be licking up those cysts and re-infecting itself.
As I mentioned, Giardia is a potentially zoonotic disease, so it is important for us to think
about ourselves and the staff members. The main species of Giardia that weíre talking
about today is Giardia duodenalis, and it has several sub-groups, which are called assemblages.
Different ones have different zoonotic potentials. Some infect humans and some do not. A and
B assemblages are the ones which can affect animals, cats, dogs, wildlife and livestock,
etcetera. These are the ones that weíre worried about to potentially cause disease in humans.
Assemblages C and D are specific to dogs, and F is specific to cats. These are ones
weíre not so worried about.
Now the question is, [if] we have an animal with Giardia how do we know if this is going
to be a zoonotic issue in our shelter? Unfortunately, the answer is [that] we donít know, because
we only can find out what assemblage an animal has if we do DNA testing at the laboratory.
This is something which is expensive and time consuming. Most shelters are not going to
be doing this on a routine basis. Itís just the reality.
So the risk ? and Iíve looked at a few papers on the subject. It looks to be [that] maybe
half [of] animals are carrying potentially zoonotic forms of Giardia. Whether or not
it actually goes on to infect humans is a different issue. Some studies have shown that
there actually may be a lot of animals ? your pet cats and dogs could be holding a zoonotic
form of Giardia. Going on for a bit more, [regarding] studies in the United States,
there are a couple of surveys looking at pet cats and dogs and the prevalence or how common
the disease is. [They report that it] is around four or five percent.
Fast forwarding to shelters, we can see that the prevalence is a lot greater. Same thing
for kennels and catteries. Animals housed in group conditions with issues of hygiene
and sanitation, obviously weíre going to have more disease. But of course, itís going
to vary where your shelter is. What are the ages of the animals that are infected? What
are your protocols and your husbandry procedures for your shelter? That is really going to
impact how much disease you have.
A couple of quick risk factors for giardia infection. We most commonly see it in young
animals. These are animals under one year of age. In adults, itís less common, because
we think they get an acquired immunity. They already have antibodies and theyíre able
to fight off the Giardia. So, weíre really looking at young animals for this disease.
The presence of other diseases. Quite often in our shelters we see young animals that
have a variety of parasites ? you know, roundworms, other protozoa, etcetera ? and these are going
to make your clinical disease much worse. Itís not just the Giardia which is causing
them to have diarrhea.
Very importantly with Giardia [it] is a seasonal pattern. When itís wet, rainy and cold [in]
autumn and winter, that is when weíre going to see more disease, because the cysts live
happily in puddles and in wet environments. They are not going to be killed as easily.
Clinical signs. You guys already nailed it on the head. Weíre thinking about diarrhea,
inappetence or anorexia, weight loss or a kitten thatís not growing so well. These
are all classic, clinical signs. We also can see vomiting, but it is less common. What
I need to draw your attention to, which is very important, is [that] many animals with
Giardia have no clinical signs. These animals are asymptomatic. They are infected and they
are potentially shedding and contaminating the environment, but we do not know just by
looking at them.
Now that we know a little bit about Giardia, we need to go on the man hunt. How are we
going to find it? The classic way for looking for Giardia is through a microscope of fecal
samples. We need to do our examination with a special zinc sulfate flotation, which is
not the normal way we do flotations if any of you have been involved in doing a little
microscopy in your shelter. Itís not the normal way we look for parasite eggs. Itís
a special solution.
The cysts are very small. They can look like yeast and are very delicate, which is why
we need the special solution. Otherwise, we might not be able to find them. Basically,
we need experienced personnel to look at these slides. Not just anyone can [take] a fecal
sample to the microscope and find Giardia.
The other really important point I need to labor is that even if we go and get the sample
from the animal thatís sick, they may not have cysts in the feces at that particular
moment. We need to go and get another sample and another sample. We recommend at least
three samples over the course of several days, so weíre screening multiple times to increase
our sensitivity and likelihood that we will find one of those cysts.
Hereís actually quite an unusual slide, now that Iím thinking about it ? the trophozoite,
which is a fancy word for adult Giardia, and one of the cysts. Usually, we are just looking
for the cysts on the slide, because the adults donít survive well in the environment. Itís
really the cysts that weíre concerned with. That just gives you an idea what they look
like. If youíve ever looked for other parasites under the microscope, you might recognize
some of these eggs. We have the roundworm, the whipworm and the hookworm, [which is]
massive compared to the size of a Giardia cyst. If you donít know what Giardia looks
like, if youíre not looking for it, you can see how easy it would be to miss [it] on a
routine examination.
What other options do we have for diagnosis, since clearly, looking [for it] on the microscope
is maybe not the best solution for everyone? Luckily, we have the magic SNAP test and I
am sure most of your shelters have used SNAP tests. It is just like all of the other SNAP
tests we use. It is looking for a special protein in the feces thatís going to be present
whether or not the animal is shedding cysts. Thatís really great for us. Itís much more
sensitive. We are more likely to get a good result using SNAP tests.
There are other lab tests available. There are amino assays and the PCRs, but for most
shelters what weíre really going to be dealing with is the microscope and the SNAP test.
Remember, in the back of your mind, there are other options.
Now we diagnosed our animal with Giardia. Now what are we going to do? Weíre going
to treat it. The first question we have to ask is ìWho are we treating?î If we have
an animal, which is clinically ill, we SNAP them. We get a positive. Yes, weíre going
to treat them. What if we have done a fecal and we found Giardia, but theyíre not sick?
Are we still going to treat them? If you have five kittens in a cage together and one of
them comes up positive with Giardia are we going to treat all the kittens in that cage?
I see some nodding in the back. Very good, alright. What I really want to labor is that
our treatment is aimed to resolve the diarrhea. We want the animal clinically healthy so we
can get them out to adoption or just out of the shelter. We donít necessarily want to
make them SNAP negative. Weíre not necessarily going to get rid of the Giardia, and thatís
something really important to keep in mind.
[My] favorite choice of drug at the moment is fenbendazole, or you may know it PanacurÆ,
which works in cats and dogs. Easy. Give it once a day for five days. Pretty good results
to resolve clinical signs, lessen the diarrhea and get rid of the Giardia.
Another option, which some people have been experimenting with is febantel combination
products, also known as DrontalÆ Plus, which is licensed in dogs. Some people have been
experimenting with its use in cats, and there has been some success.
Another popular drug that people use for Giardia is metronidazole. Itís gone out of fashion
recently because high doses can cause neurological signs, can cause birth defects and shouldnít
be given to nursing mothers. Of course, Giardia can become resistant to metronidazole, so
you can see how that would be a problem. [With] resistant Giardia, people keep increasing
the dose, and suddenly you have all these adverse effects.
Now that weíve done our drug protocol, we need to focus on the rest of the animals and
the rest of the shelter. Unfortunately, this means bathing our cats. We need to prevent
re-infection. All the cysts that are stuck in the fur, we need to get them out. Weíve
got to wash our cats and dogs. We have to clip them if theyíre going to be matted or
getting really dirty in their hind end. We need to clean the environment, so whatever
cage theyíre in we have to make sure that we are going to move them to a clean environment.
We are going to move them out of the space where they were infected with Giardia, where
all the cysts are in the environment. Weíre going to move them into a clean cage, so that
theyíre not going to be licking the walls and getting more cysts. Weíre going to be
promptly removing the feces in that new, clean environment, because even though weíre treating
them they still could be shedding cysts. If they step in it or contaminate their food,
it is just going to make the process harder. Theyíre going to be re-infecting themselves.
So, now we need to deal with our original cage, which has been contaminated by all these
feces and the cysts. The first thing weíre going to do is weíre going to scrub. Weíre
going to physically get in there, manually remove as many cysts as we can with just soap
and hot water and get rid of what we can. Weíre going to remove our soap. Weíre going
to rinse it out and let it dry. The reason why weíre doing these first two steps ? getting
rid of all of the gunk and newspaper and whatever is left in the cage and drying it ? is so
that our disinfectant is more effective. The disinfectant of choice that weíre using is
a quaternary ammonia compound, or QUATS. There are some brands you might be familiar with.
These have been proven to be quite effective at getting rid of the cysts, so the cysts
that we havenít scrubbed out should be killed by the QUATS.
We want to make sure we have a good contact time. We want to make sure we leave that QUATS
on there for at least ten minutes. Check the label [of] whatever product youíre using,
because we really want to make sure weíre killing all those cysts that are residual,
still in the cage.
Weíre going to wipe it clean and then finally, most importantly, weíre going to dry it.
Cysts, like I said, they live in the winter. They live in the wet. They live in the damp.
We need to get it dry, so we can desiccate those cysts, make them so theyíre no longer
infective. They can survive for weeks or months in a damp environment, so we really need to
keep that in consideration when weíre cleaning our cages. You canít just hose it down and
shove new animals in.
This is a picture from a shelter in New Zealand, where I did a couple of rotations where they
had chronic, chronic Giardia and other parasite problems. You can see where it says, ìAnimal
housed.î Is it indoor or outdoor?
Audience: Looks like outdoors.
Dr. Hoshizaki: Outdoor and Iíll tell you, New Zealand has about as much rainfall as
Seattle. Itís always wet, so this dog is in a place that theyíre never going to be
able to clean this kennel, right? Itís going to be always contaminated with these cysts,
no matter how hard they try, just because of the nature of wood and being outdoors.
So, now weíve treated the individual animal. We need to think about everyone else who could
be affected by the Giardia. What we need to do is prevent the spread throughout the shelter
to the other animals. Weíre going to place appropriate signage. Weíre going to put a
big, old sign on the cage and say, ìI have Giardia. Wear gloves. Wash your hands.î Ideally,
limit handling to those who know about Giardia, know the zoonotic potential and know how to
handle it, so theyíre not spreading it throughout the shelter. Not every volunteer should be
cuddling the Giardia puppies.
We need to have appropriate cleaning protocols and this applies, of course, across all the
diseases weíre dealing with. If we have good protocols weíre going to be eliminating all
the different diseases, not just Giardia. By picking up the feces and keeping it clean
weíre preventing re-infection of all the diseases, not just Giardia. We are going to
allow the cages to dry before we add animals again.
Weíre going to keep the animals separate. Iím not saying you have to isolate them.
This isnít like upper respiratory, where they need to go into a separate room necessarily,
but we donít want to mix them. If the puppy with Giardia goes out into the play yard and
then you have all your other dogs come out into the play yard, whatís that going to
do? Thatís not going to be helpful for your treatment regime, because theyíre going to
be contaminating that environment. Theyíre going to be contaminating the community cat
room or the hallway where everybody walks. So, you need to be conscious of where youíre
taking these animals and what other animals have access to that space. Of course, we donít
want to be mixing animals, especially litters. You donít want to be putting sick animals
in with the non-sick ones. Itís common sense, right?
Because young animals are more easily, or at least more commonly, infected ? we see
them as clinical disease in the young animals ? we want to keep them in easily cleaned cages.
We donít want to put them into the nice, posh cat room with all the furniture. We want
to keep them somewhere that we can clean in case they do get sick.
I already touched on this. What are you going to do when one of those cats starts having
diarrhea, we SNAP test it and it comes back positive for Giardia? Weíre going to get
rid of all the furniture that we canít clean and all [of] the carpeting. Weíre going to
get rid of all [of] those toys and all [of] the blankets. It looks like in this picture
that they have cardboard little hidey-holes. [That is] great, because we can throw those
away? the cardboard hidey-holes and cardboard litterboxes. These are things we can get rid
of. Itís not a great cost.
We are going to be treating that one particular animal and weíre probably going to be treating
all the other animals in that environment, because even though they donít have diarrhea,
they have been exposed. Chances are they could be asymptomatic, but still infected.
Of course, we are going to be putting up signs on this door. This looks like probably an
adoption area, so we want to make sure that everyone knows whatís going on in this room
and weíre not just tracking Giardia in and out.
What about this? There are a few interesting things in this picture. Thereís a pool, a
very nice swimming pool, for the dogs. Thereís a wooden pagoda, and thereís gravel. Gravel
is not as bad as dirt and grass, but Iím sure you can imagine if a dog with Giardia
defecates in that yard that gravel is contaminated. How are we going to contain that? Same thing
with the pool and with the wooden pagoda. How are we going to contain that? We might
end up having to resurface our play yard. That is not something anyone wants to do.
Audience: Is there any type of treatment where you can treat the yard?
Dr. Hoshizaki: Thatís a very good question, and Iím hesitant to give a direct answer
to that, because I guess it depends. If the animal goes to the bathroom right away, and
weíre able to pick it up immediately, is all the soil around it infected? Or has it
been chronically infected with Giardia and all the dogs have been kicking up the dirt
and itís that we have layers and layers of cysts in the soil? Iím not aware of any recommended
protocol really for that, unfortunately. In some situations you just canít get around
it.
Resolution. So we come back two weeks later, after weíve been treating our animal, and
weíre going to do a SNAP test again or look under the microscope again. If the animal
is still sick, weíre going to still treat. No brainer. But, we need to think why did
our treatment fail? Why did the animal potentially re-infect itself? Did we not sufficiently
clean it? Did we not keep their environment clean? Did we put them in an environment,
which has cysts still in it? We need to keep these things in mind, because re-infection
is more common than treatment failure. We may want to consider a different drug protocol
if we think we didnít use the correct dosage or the right amount of time for the drug to
take effect.
We also need to look for other causes of diarrhea. Like I said, Giardia might just be one part
of the problem. The animal might have some other issue, or other parasite, which is causing
the disease and we need to make sure we have ruled those out as well.
Now we have to think about adoption. If we have an animal [that] we have treated for
Giardia, it is healthy, but itís still SNAP positive, what do we do? We need to weigh
the pros and cons and how weíre going to tackle this adoption. Of course, always in
the back of the mind weíre thinking, ìWe are adopting out an animal that has a potentially
zoonotic disease and what does this mean for our adopters?î
We need to remember that immunocompromised humans are at risk, so people with certain
diseases and children. Giardia can be very life threatening for them, so we need to consider
what kind of home weíre placing this animal in. Many shelters have chosen to do a waiver.
Of course, client communication and education is very important. We are going to have someone
sit down with them, and explain to them that they are adopting an animal with Giardia and
this is what it means. We can have them sign a waiver to help negate some liability on
the shelterís behalf, but as you probably can figure out, thereís no great way of completely
reducing the risk.
As another side, if youíre adopting out a cat with Giardia and youíre adopting it out
to the nice old lady who has six other cats, what does that mean to her whole household?
Are there going to be repercussions down the road ? that youíre going to feel quite bad
about if she comes up with a bunch of sick cats?
I asked the question, ìWhat is Giardia?î Now, in your mind, Iím hoping a few more
light bulbs are going off. Itís not just diarrhea, right? It is a common disease. Dogs,
cats, humans and other animals, we need to be aware, have Giardia. Itís a challenge
to control depending on what kind of rooms your animals are housed in, what kind of cages
and what kind of sanitation protocols you have. Control really depends on how youíre
taking care of your cleaning in that shelter.
Always remember, animals that are healthy could still have Giardia. Animals that you
treat could still have Giardia. We need to consider the risks, and decide what is best
in our shelter situation of how weíre going to deal with this problem.
If you would like some light reading, I can offer some excellent references. Thatís the
end. I would like to thank Maddieís FundÆ, the ASPCA and Cornell University for having
this talk and for having me. Iíd like to it open up to any questions you guys may have.