Hissy Spitty, Squeaky and Giardia

Giardia cell, SEM.

Image via Wikipedia

If you read yesterday’s post, you’ll recall that Hissy Spitty and Squeaky refer to Alice and Lulu, two of the hospital’s adoptable kittens, who have Giardia. For weeks, they’ve had intermittent soft stool. We changed their diet, with no improvement, and so, have found the cause to lie in Giardia.

– Scientific Classification –

The parasite Giardia is the agent most frequently identified in outbreaks of water-borne disease. It is a zoonotic disease as humans can contract it through ingesting contaminated material. Daycare centers have been a region of transmission. The cysts expelled in feces are what transmit the disease. They are elliptical in shape and have 4 nuclei.

Signs of giardiasis occur about a week after infection. They include:

  • diarrhea (and subsequent dehydration)
  • excess gas
  • stomach or abdominal cramps
  • upset stomach
  • nausea

Giardia Life Cycle via CDC

To diagnose Giardiasis, trophozoites or cysts must be seen in fecal smears or fecal flotation. This may be difficult as cysts are shed intermittently. Generally, 3 fecal samples are collected over a period of a week to 10 days. The disease can be treated with tinidazole or metronidazole. The kittens are being administered the latter I believe.

On a side note, in the course where I first learned about Giardia, the doctor giving the guest lecture had a giant tattoo of this old man-looking parasite on his upper arm. Science lovers are weird…slash awesome…







Lulu (who wouldn't pose well for me)



  • Wikipedia – Giardia
  • Introductory Parasitology notes – taught by Dr. Zajac at Virginia Tech

Related Articles


Nat Geo :: Guinea Worm in retreat in southern Sudan

Guinea Worm in retreat in southern Sudan – News Watch. (April 8, 2010)

I found the preceding article in lieu of the one I’ve just read in National Geographic’s July 2011 issue. The title of the short article is “Farewell to Guinea Worm” (Dracunculus medinensis). It’s an example of how quickly eradication efforts can work with the right circumstances. The Nat Geo article cites “education” as their most effective tool towards eradication. Teaching the locals how to go about drinking from their water supply (filter straws or fabric) and about the worm’s life cycle, gives them the tools to protect themselves.

Guinea Worm (Dracunculus medinensis) Life Cycle via CDC

The guinea worm disease (Dracunculiasis) isn’t fatal but can cause severe pain and put people out of work. The allergic reaction to the worm can cause diarrhea, nausea, rashes, and edema, among other symptoms. The death of an adult worm nestled in joints can lead to arthritis or paralysis (if in the spinal cord). Dracunculiasis may be the next disease to disappear, after smallpox!


The Sweetest “Caution” Dog Ever Who Just Happens to Have Heartworms (Dirofilaria immitis)

Pitbull - Kim

Image via Wikipedia

The perks of working at a vet hospital when you have a science based blog, is that it’s really hard to run out of material. At the moment, we have a pit bull waiting for adoption who is reported to be dog and cat aggressive and is also heartworm positive. He’s probably the sweetest dog ever (imagine the dog in the picture, only black), he just doesn’t seem to know how strong he is, which he displayed this morning by jumping all over me.

I’m sure most people have heard about heartworms and that they’re dangerous to our pet’s health but people may not know just how much.

– Scientific Classification –

Dirofilaria immitis is the canine form of heartworm, with other definitive hosts being wild canids and ferrets. Cats are an abnormal host. The worms are long and thin and the females can reach 28 cm. Adult worms are found mostly in pulmonary arteries and also in the righthand portion of the heart. There is a 6 month prepatent period with a minimum of 2 weeks inside the mosquito (who serves as the vector). Adult worms can live for 5 years.

Some cases of heartworms can be asymptomatic. Mild to moderate disease can result in a chronic cough and decreased exercise tolerance. Moderate to severe cases can lead to syncope (fainting), hemoptysis (coughing up blood), pulmonary hypertension, right heart enlargement and failure.

Diagnosis is based on an antigen test (for adult females), which is the most sensitive option. A dog can be tested after the 6 month prepatent period or just prescribed a preventative. Preventatives that can be prescribed are macrolides and are a monthly product. They kill heartworms acquired in the previous month.

The pit bull in our care doesn’t seem too bothered by his disease as of late. Hopefully he gets adopted by someone who can handle him soon!

Also, an update on the Old English Sheepdog :: she wasn’t in the treatment room when I worked today so hopefully she went home and is feeling better!

:: Information from this post is from my notes from an Introductory Parasitology class taught by Dr. Zajac at Virginia Tech ::

Parasite Terminology

The Stages of Toxoplasma gondii

T. gondii constructing daughter scaffolds with...

Image via Wikipedia

As stated in Toxoplasma gondii, today I’m going to break down the stages of the parasite. Those stages are:

  • Sporulated oocysts (sporozoites) from environment
  • Tissue cysts containing bradyzoites in raw/undercooked meat
  • Tachyzoites in tissues
  • Entero-epithelial stages (only in cats)

Oocysts are produced non-sporulated but will sporulate in about 2 days. They are about 10×10 µm and millions can be produced within days. Cats can develop strong immunity to this stage.

In the intermediate host, the life cycle is as follows:

  • Excystation of sporozoites
  • Sporozoites –> Tachyzoites
  • Tachyzoites disseminate infection and eventually become bradyzoites or tissue cysts
  • Latent infection
  • Endodyogeny (a form of sexual reproduction)

Tachyzoites have a fondness for neural and cardiac tissue but can infect any nucleated cell in the body. This is the stage that crosses into the placenta and causes congenital infections. Rapid division of tachyzoites is what causes tissue destruction, the spread of infection and lesions.

Bradyzoites (“brady” = slow) are responsible for tissue cysts. They can be present in any organ and survive for the life of the infected animal since they are resistant to the drugs used to treat Toxoplasmosis. If the host is immunocompromised, infection can be reactivated and intermediate hosts can infect one another. Bradyzoites are at fault for initiating meat induced infection, on top of being the only stage to give rise to entero-epithelial stages.

Once again, the etero-epithelial stages are only found in cats. There are 5 types of entero-epithelial schizonts (which will not be listed). This is where the sexual stages/oocysts are produced.

Overall, Toxoplasma gondii was the most successful parasite discussed in my Intro Parasitology course.

:: Information from this post is from my notes from an Introductory Parasitology class taught by Dr. Zajac at Virginia Tech ::

Toxoplasma gondii

life cycle of Toxoplasma gondii

Image via Wikipedia

This is the second post in relation to Feral Pigs : From Piglets to Problem. Once again, general parasite terminology can be found here.

– Scientific Classification –

Toxoplasma gondii was first described in 1908 after being found in the gundi ( a North African rodent). It is found in most mammals and birds with cats as a definitive host and a rodent as a common intermediate host as well as humans and other warm-blooded animals. Tissue cysts, the asexual stage of the parasite, occur in the intermediate host while the sexual stages and oocysts occur in the definitive host. Oocysts develop in the environment, after being excreted in the feces, where they sporulate. Infection, called Toxoplasmosis, can lead to ocular infections, immunosuppression, and organ transplantation. Congenital infections (pregnant female with the infection, infects fetus) were recognized in humans in 1923.

The different stages of T. gondii are:

  • Sporulated oocysts (sporozoites) from environment
  • Tissue cysts containing bradyzoites in raw/undercooked meat
  • Tachyzoites in tissues
  • Entero-epithelial stages only in cats

[These stages will be broken down in a later post.]

Cases of Toxoplasmosis are most severe in congenitally infected young or an immunosuppressed individual. Common conditions after infection are pneumonia, hepatitis, encephalitis and ocular disease. Tachyzoites cause tissue destruction but the cysts do not cause lesions or an immune response.

Human Toxoplasmosis:

Sources of human Toxoplasmosis include undercooked meat containing tissue cysts (such as pork in the U.S., lamb or goat in other countries and meat from wild animals), and oocysts from contaminated produce, soil, water, litter boxes, etc. A previous infection may not always prevent congenital infection if the strain acquired by the mother is genetically different. Maternal testing for Toxoplasmosis is not required in the U.S. but is by law in France and Austria. Sera is tested for antibodies and if results are negative, the patient is retested monthly. If positive, doctors must rule out recent or active infection.

In animals, T. gondii infections are mostly asymptomatic. It can cause abortions in sheep, goats and pigs but only a generalized infection in cats. Infection is fatal to Australian marsupials, arboreal monkeys, lemurs and perhaps certain avian species.

:: Information from this post is from my notes from an Introductory Parasitology class taught by Dr. Zajac at Virginia Tech ::

Trichinella spiralis

Trichinella LifeCycle

Image via Wikipedia

If you read Feral Pigs: From Piglets to Problems, you might recall that Trichinella spiralis was one of the parasites mentioned. I was fortunate enough to have an Introductory Parasitology class at Virginia Tech (full of really interesting and disgusting things that induce paranoia) where this and Toxoplasma gondii were discussed, so most of this post will be thanks to notes from Dr. Zajac’s incredible class. Many of the terms included can be found defined here.

– Scientific Classification –

The definitive and intermediate host of Trichinella are in the same animal (in this diagram, a rodent). The parasite is looking for striated muscle, and therefore as a histiotrophic parasite, spends part of its life cycle within a cell or tissue where it waits for the muscle to be eaten. ANY warm-blooded animal can serve as a host.

Trichinella spiralis

Image via Wikipedia

Pigs can get infected by eating garbage, rodents or each other. As pigs are omnivorous, they may eat rats which can be loaded with Trichinella. Once infected, they may not show any sign of disease.

Human infection, on the other hand, can result in enteritis, myalgia, fever, and kidney and respiratory failure if the parasites are prevalent enough. 5 larvae per gram of muscle is fatal.

To prevent infection, cook pork thoroughly or freeze it at -15˚C for 20 days or more, depending on the size.

Parasites like Trichinella have added to the perception that pork is unsafe. In the U.S., it is less of an issue now in confined pigs since they tend to be grain fed instead of fed with raw garbage. Organic and pasture raised operations have brought about concern of the re-emergence in swine. A couple of other hosts from which one can acquire infection are bears and horses. Current Trichinella cases are mostly from undercooked bear meat and the parasites can survive freezing. There have been several outbreaks of the parasite in horse meat in France and even some U.S. horses.

:: Next post: Toxoplasma gondii ::

Parasite Terminology

H. diminuta life cycle.

Image via Wikipedia

:: The image chosen is of the life cycle of a specimen that I actually have a jar full of in my room… ::

Before I dive into aspects about the parasites mentioned in my last post (Trichinella and Toxoplasma gondii), I thought it would be a good idea to post a few definitions of frequently used terms. For future parasite posts, I’ll be sure to try to include a link here to make it easy on new readers, or just in case you’ve forgotten.

  • Life cycle: entire life history including stages and hosts
    • Direct: only one host
    • Indirect: one or more hosts
  • Definitive host: host in which parasite reaches (reproductive) maturity OR sometimes the most important host to us
  • Transport (or paratenic) host: no development occurs, used to get closer to necessary host (eg. marine parasite)
  • Intermediate host: necessary part of life cycle; immature parasite cannot reach maturity without it (eg. heartworms need stage in mosquito before infecting dog)
  • Patent infection: period when parasites are mature and reproduction occurs, parasite produces evidence of infection (eg. eggs)
  • Prepatent period: period following infection before parasites mature; often before infection can detected by microscope
  • Zoonosis: disease transmitted from animal to human
    • Reservoir host: animal carrying infection that can be transmitted to humans
    • Vector: agent (usually arthropod) transmitting disease
  • Helminth: worm
  • Anthelmintic: dewormer
  • Geohelminth: helminth acquired directly from the environment without intermediate hosts or vectors (term used for human intestinal parasites)
:: The information from this post is from my Introductory Parasitology notes taught by Dr. Zajac at Virginia Tech ::