|Adults of T. cati|
Toxocara cati (toxo=arrow + cara=head;synonym Toxocara mystax, common name feline roundworm) is worldwide distributed parasite of cats and other felids and it is one of the most common nematodes of cats. This parasite is dangerous as it can infect both wild felids as well as domestic felids. Adult worms are localised in gut of the host. In adult cats, the infection is usually asymptomatic. However, massive infection in juvenile cats can be fatal.
Adult feline roundworms may be brownish-yellow to cream colored to pink and may be up to 10cm in length. Adults have short, wide cervical alae giving their anterior ends the distinct appearance of an arrow (hence their name). Eggs are pitted ovals with a width of 65μm and a length of about 75μm making them invisible to the human eye. The larvae are so small that they are easily transmitted from an adult female to her nursing kittens through her milk.
Contact with the roundworm species for wild felids can come from a variety of sources. The primary source of contact with this species is contact with infected fecal matter. The eggs of the roundworm become infective in three to four weeks after being passed out in fecal matter (Webmd.com 2008). Contact with the soil, licking fur near feet, and eating a host animal (such as rodents) can also lead to infection of the felines (Webmd.com 2008). The consumption of infected carrion also leads to contraction of the parasites, which is some of the food that members of Felidae consume (Umich.edu 2013). The eggs hatch in the intestines and the larvae are then released into the cat’s digestive tract (Web.md.com 2008). The larvae are capable of migrating through the tissues of the wild feline (Web.md.com 2008). The larvae use the blood of the feline to lungs (Web.md.com 2008). From there, they move up to the trachea where they are swallowed causing hacking and other problems (Web.md.com 2008). The larvae can also move throughout the body and cause more damage to the infected individuals. The worms can even go into the mother’s milk and infect the young (Web.md.com 2008)
There are numerous clinical signs when dealing with Feline Roundworm. Some clinical signs that can be detected easily are vomiting, decreased appetite, and poor growth (VCAHospitals.com 2013). Like many diseases, changes in behavior can also attribute as a symptom of any individuals infected with roundworms. The decreased appetite will result in individuals appear scrawny, mangy, and sickly. The poor growth and decreased appetite is exceptionally detrimental to kittens, as the appetite loss and poor growth will ultimately lead to mortality since this time of growth for kittens is very important. The mortality of kittens will lead to continual decrease of the population as there will be fewer kittens to replace adult mortality. Additional clinical signs that can be identified at closer examination include pot bellied appearance, abdominal discomfort, and diarrhea (VCAHospitals.com 2013). Those with a small number of worms, however, may not show the clinical signs of being infected with worms (VCAHospitals.com 2013) resulting in it being hard to determine if individuals have roundworms.
Unfortunately, little research has been done as far as identifying the roundworm in wild felid populations. There are some detection methods that have been used in order to help identify roundworm infestation. Possible detection methods for discovering feline roundworm include noting changes in behavior. The change in behavior can be identified through from eyewitness accounts. As change in behavior can include a lack of fear towards humans, eyewitness accounts can be imperative for identifying round worm. Although, detecting the individuals, never mind the infected ones, may prove to be a challenge. Felids especially are hard to detect for roundworm as they are naturally loners by nature (with the exception of the lion, who forms prides) and are cryptic by nature (Umich.edu 2013). Another method to help determine the possibility of roundworm infection is transect studies. The studies implement individuals walking along transects and spotting animals and noting for any unusual behavior within animals of populations. The transect studies, however, need suspicion of infection in order to be implemented. To that end, many DNR (Department of Natural Resources) and other wildlife organizations (such as the US Geological Survey) allow people to provide information regarding suspicion of infection (USGS.gov 2013). These organizations will then have people fill out a sheet detailing the mortality event, such as this one here:
For organizations such as the DNR, reporting individuals that have been viewed (Wi.gov 2013) aids in the detection of individuals infected by roundworm. The contacted DNR will then proceed with the proper procedures to work on dealing with the possibility of roundworm infestation in the area. Many agencies use fecal matter testing and studies to identify the presence of parasites within a population. Agencies take the fecal matter of a suspected population and test the contents for the presence of eggs or remains of adults. Many parasites often pass their eggs through the animal’s fecal matter and as Durant et al (2012) stated, identification is paramount to reduce the chance of disease or mortality. Soil samples (2012) around the fecal matter are also taken and tested in order to ensure that there is an active roundworm population. Road kill samples also prove to be a way to detect individuals who are infected with roundworm. This is due to animals often acting differently when diseased, as shown from canine distemper, which over time, causes changes in behavior such as losing the fear of humans, becoming unnaturally aggressive, and wandering aimlessly (Tn.gov 2013). These samples can be recovered and then examine for the possibility of roundworm.
Some treatments for infection with Toxocara cati include drugs designed to cause the adult worms to become partially anaesthetized and detach from the intestinal lining, allowing them to be excreted live in the feces. Such medications include piperazine and pyrantel. These are frequently combined with the drug praziquantel which appears to cause the worm to lose its resistance to being digested by the host animal. Other effective treatments include ivermectin, milbemycin, and selamectin. Dichlorvos has also been proven to be effective as a poison, though moves to ban it over concerns about its toxicity have made it unavailable in some areas.
Treatment for wild felids, however, is difficult for this parasite, as detection is the best way to find which individuals have the parasite. This can be difficult as infected species are hard to detect. Once detected, the infected individuals would have to be removed from the population, in order to lower the risk of continual exposure to the parasites. A primary method that has been used to lower the amount of infection is removal through hunting. Removal can also occur through landowners, as Dare and Watkins (2012) discovered through their research on cougars. Both hunters and landowners can provide samples that can be used to detect the presence of feline roundworm in the area, as well as help remove it from the population. This method is more practical than administering medications to wild populations, as wild animals, as mentioned before, are harder to find in order to administer medicinal care. Medicinal care, however, is also another method used in round worm studies; such as the experiment on managing raccoon roundworm done by Smyser et al. (2013) in which they implemented medical baiting. However, medicine is often expensive and the success of the baiting depends on if the infected individuals consume the bait. Additionally, it can be costly (in time and resources) to check on baited areas. Removal by hunting allows agencies to reduce costs and gives agencies a more improved chance of removing infected individuals.
“Canine Distemper”. Tennessee Wildlife Resource Agency. 24 Oct. 2013. http://www.tn.gov/twra/distemper.html
Dare, O.K. and Watkins, W.G. “First Record of Parasites in Cougars (Puma Concolor) in Manitoba, Canada”The Canadian Field Naturalist. 24 Oct. 2013. http://www.canadianfieldnaturalist.ca/index.php/cfn/article/view/1378/1373
Durant, Jean-Francois et al. “Duplex quantitative real-time PCR assay for the detection and discrimination of the eggs of Toxocara canis and Toxocara cati (Nematoda, Ascridoidea) in soil and fecal samples” Parasites and Vectors 2012 5:288
“Instructions for Reporting Wildlife Mortality Events”. USGS: Science for a changing world. 24. Oct. 2013. http://www.nwhc.usgs.gov/mortality_events/reporting.jsp “Roundworms” Department of Natural Resources. 24 Oct. 2013. http://www.michigan.gov/dnr/0,4570,7-153-10370_12150_12220-27263--,00.html
“Roundworm in Cats”. WebMD. 23 Oct. 2013. http://pets.webmd.com/cats/roundworms-cats
“Roundworm Infection in Cats”. VCA Animal Hospitals. 23 Oct. 2013. http://www.vcahospitals.com/main/pet-health-information/article/animal-health/roundworm-infection-in-cats/336
Smyser, Timothy et al. “Managemet of Racoon Roundworm in Free-Ranging Populations via Anthelmintic Baiting” Journal of Wildlife Management 77:1372-1379
“Wildlife Health an Rehabilitation”. Wi.gov. 24 Oct. 2013. http://dnr.wi.gov/topic/wildlifehabitat/wildlifehealth.html
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