Don’t let Isospora run your shelter down

As spring has transitioned into summer, the Maddie’s Shelter Medicine team has been focusing on what flourishes most this time of year: kittens and parasites! What comes to mind next? That’s right, diarrhea. Neonatal parasitic diarrhea is a common condition that can give any shelter a run for its resources. This week’s article will focus on a frequent culprit: the coccidian parasite Isospora.

kittens playing in litter box

Isospora ssp. are a type of protozoal parasite. Interestingly, these parasites can be found in the feces of healthy adult animals, resulting in no illness at all. Healthy animals become immune to Isospora and eventually clear the infection. However in young or immune-compromised animals, this type of coccidian parasite can invade the cells of the intestinal track resulting in severe inflammation. Inflammation interferes with the ability of the intestinal track to absorb nutrients and fluid. The resulting symptoms may include diarrhea with or without blood, vomiting, and weight loss. Rarely death may result from severe dehydration or secondary bacterial infections.

Isospora ssp. are diagnosed by the identification of oocysts via microscopic examination of feces. For most shelter puppies and kittens with diarrhea, diagnosis of Isospora will be presumptive due to the common nature of these organisms. Additionally, diagnosis can be challenging, as the coccidian organisms may not be shedding their oocysts at the time of fecal analysis. However, for refractory cases of diarrhea it is a good idea to submit feces for microscopic evaluation, whether performed in the shelter or at a veterinary diagnostic laboratory. Fecal analysis may confirm Isospora or reveal additional parasites resulting in a co-infection, requiring further treatment.

Isospora oocysts

Isospora oocysts


The current recommended treatment for Isospora ssp. in shelters is ponazuril. Ponazuril is an equine product used off-label as a coccidial-cidal agent for dogs and cats. Because coccidian parasites are so common and infection can be very severe, it is recommended to treat all puppies and kittens four weeks of age and older with ponazuril at the time of intake. Ponazuril can be purchased as Marquis Paste. It can then be diluted to 75mg/ml by mixing 10ml of paste with 10ml of water. Ponazuril is dosed at 30mg/kg once daily by mouth for 1-7 days depending on the presence and severity of diarrhea. Treatment may need to be repeated in severe cases.

Isospora may be spread through fecal-oral transmission, vector transmission or by ingestion of an intermediate host. In addition to minimizing the shedding of Isospora via prophylactic treatment, it is very important to minimize exposure to the infective oocysts through proper cleaning and disinfection. Oocysts are infectious immediately upon passage from the infected animal. Therefore, prompt removal of feces from play yards, housing units and litter boxes is essential to prevent exposure to litter mates and other shelter animals. Regular pest control is vital to prevent transmission via insects and rodents. Lastly, it is important to know that oocysts are environmentally persistent. For known or suspected cases of Isospora, deep cleaning of housing units with bleach diluted 1:32, or steam cleaning will ensure the oocysts are destroyed. Additionally, consider disposable litter boxes for kittens and adult cats with diarrhea as oocysts can remain in defects within the plastic of traditional litter boxes.

Disposable litter boxes

Disposable litter boxes


We hope you find this information useful as your shelter continues through the summer months of kittens, puppies and diarrhea! As with many pathogens encountered in shelters, Isospora can result in severe neonatal disease. However, with preventive techniques and good cleaning protocols, Isospora will not erupt in a diarrhea outbreak.

For information on fecal sample submission, visit the following link:

Tritrichomonas foetus: What shelters need to know

Tritrichomonas foetusTritrichomonas foetus, also know as “tritrich” or T. foetus, is a relatively new parasite of cats which is gaining recognition in the shelter community. T. foetus is a flagellated protozoa, which is similar to Giardia spp. in many ways. T. foetus is most common in catteries and sanctuaries, but can also be found in shelters or privately owned animals.

Like many gastrointestinal parasites, T. foetus is spread by fecal contamination (shared litter boxes, grooming after stepping in feces, etc.).  Infected cats can have gassy, malodorous diarrhea, or no clinical signs at all. In private practice many owners may be reluctant to treat, as signs can be mild to non-existent. However, this parasite can be devastating in a shelter situation due to the chronic nature of infection. Cats which are untreated can take up to two years to clear the infection, and some remain infected for life.

T. foetus can be challenging to diagnose, for a number of reasons. Unlike most parasites, which can be found on fecal flotation, T. foetus requires specialized testing. The parasites are rare, so finding them can be difficult. Additionally, antibiotics, contamination, and poor sample handling can cause false negative results. T. foetus can be diagnosed by either fecal smear, fecal culture, or DNA testing (PCR). DNA testing is the best, but the most expensive and often requires the use of a referral laboratory. Fecal culture and smears are less likely to find the infection, and require some skill on the person doing the test. Watch the following video to see why T. foetus can sometimes be mistaken for Giardia spp. under the microscope.

While diagnosis can be hard, treatment can be even harder. The most commonly used drug is ronidazole, which is in the same drug family as metronidazole. Ronidazole  is most commonly used as an anti-protozoal and anti-bacterial agent in turkeys, pigeons and pigs. Ronidazole is not FDA approved for use in cats and poses human-health risks. While initial studies have shown that ronidazole is a promising treatment option in cats with T. foetus, some cats experience severe side effects. Signs of toxicity include lethargy, anorexia, stumbling gait, seizures, and even death. Treatment failure is common, leaving shelters with cats that have chronic, infectious diarrhea, which will be challenging to manage and to adopt out.

T. foetus is easily killed in the environment; thus the best way to control spread of infection is through sanitation and disinfection. Infected or suspect cases should be isolated from healthy cats, especially those who are sick or immuno-compromised. If you think your shelter cats may have T. foetus , then please contact your local shelter veterinarian, or the Cornell University Shelter Medicine Program for assistance with diagnostics and treatment.

For more information about Tritrichomonas foetus, please visit Dr. Jody Gookin’s website:

Assessing Anesthetic Needs for the Clinic

drugThose shelters that offer spay/neuter services may find themselves mulling over the ideal anesthetic protocol. What we’ve encountered is that there are a lot of variables to consider when developing a protocol tailored to your shelter’s needs. The constant variables remain the same among all clinics – adequate anesthesia, adequate analgesia, minimal stress and wide margin of safety. But what we often find through trial and error are variables that are associated with staffing, services offered,  and resources available.

Number of surgeries

Most High Quality High Volume Spay Neuter (HQHVSN) clinics perform 30-50 surgeries per day. This not only dictates a minimum staff requirement, but may demand an IM cocktail over IV induction.


As mentioned with HQHVSN, proper staffing is essential for keeping surgeons where they belong – in surgery. However staffing can also have a profound effect on what drugs are used and how they’re administered. Does the person running induction have an assistant to help with induction and to move the patient into surgery? If not, an IM protocol may be warranted for prep and intubation. What is the comfort level and skill of the induction staff? Can they intubate on their own? Can they perform IV induction? Is there someone designated to recover patients? If the same people are doing induction and recovery, patients will need to recover quickly.

Neuter vs Spay

What’s good for the girls may not be needed for the boys. Spays take longer and are more invasive requiring longer anesthesia and stronger analgesia.

Anesthetic Drugsphoto(7)

Sometimes accessibility to drugs will determine the anesthetic protocol chosen. Accessibility can include cost and proper licensing to order scheduled drugs. Drugs like dexmedetomidine are quite pricey and may be cost prohibitive if the majority of patients are large dogs. However, the volume of dexmedetomidine used can be greatly reduced when used in a combination protocol. This in turn can reduce cost. Although morphine is cheap and a terrific analgesic,  it’s not always an option for many clinics because it’s a schedule II drug and requires special ordering and documentation.

Keeping in mind that every animal is an individual and will respond differently to any anesthetic protocol, there’s a lot to consider when deciding on an anesthetic protocol to fit your program. The following resources can assist in getting started:

Asking other clinics about their experience with the protocols they use is extremely helpful. Here at Maddie’s Shelter Medicine Program, Cornell University, we are happy to discuss some of the protocols we have used and the effect they have had on our surgery day (