Strongyloidiasis: A Parasitic Infection in Pets
What Is Strongyloidiasis?
Strongyloidiasis is an intestinal parasitic infection caused by a nematode known as Strongyloides stercoralis—a species of threadworm or pinworm that can infect dogs, cats, and even humans. The worms stick to the infected pet’s intestinal lining and cause several gastrointestinal issues, like bloody diarrhea and vomiting. Unlike other parasitic worms, Strongyloides stercoralis are all females. They appear as small, thin, almost transparent worms, that can only grow up to 2 millimeters.
What’s so scary about Strongyloides stercoralis is that, while most of them just grow into mature threadworms, some of them can turn into filariform larvae. These larvae are capable of penetrating the skin of both humans and pets, on top of being able to cause Strongyloidiasis when ingested. In a warm and moist environment, threadworm eggs hatch even quicker and can transform into an infective larva in a span of 24 hours.
What Are the Symptoms?
Aside from bloody diarrhea and vomiting, pets suffering from Strongyloidiasis may also experience rashes or skin inflammation, loss of appetite, weakness, weight loss, constipation, dehydration, coughing, pneumonia, stomach pain, and mucus in the stool. In the later stages, infected pets may develop a fever and have breathing issues. The worst-case scenario is that the threadworms migrate into other organ tissues. When that happens, the infection can lead to death.
How Is It Transmitted?
Infected pets can shed threadworm eggs, as well as hatched larvae, in their feces in as early as 7 days after infection. Animals that come into contact with feces-contaminated surfaces and objects can pick up the parasites and accidentally swallow the infective eggs or larvae while grooming themselves. However, Strongyloides stercoralis can also be transmitted from mother to offspring through contaminated breastmilk, and the filariform larvae may just directly penetrate the skin.
How Is It Diagnosed?
It can be quite challenging for veterinarians to differentiate Strongyloidiasis from an infection caused by hookworms, bacteria, and other intestinal parasites because of how similar all their symptoms are. If you suspect that your pet has contracted Strongyloides stercoralis, your veterinarian may ask you for a fresh stool sample. Several tests will be performed and you may have to wait for a few days to receive a final diagnosis.
To identify threadworm eggs, your veterinarian will take a small amount of your pet’s feces and do a fecal flotation test. This helps to narrow down the possible diagnosis and determines whether or not your pet has an intestinal parasite. Your veterinarian may also scrape your pet’s intestinal lining for any adult threadworms or examine their stool under a direct microscope.
How Is It Treated?
Once a proper diagnosis is made, your veterinarian will prescribe you an anthelmintic medication, like Ivermectin, Fenbendazole, or Thiabendazole, to help purge out the threadworms from your pet’s body. These medications are usually retaken after about 4 weeks to make sure all the worms and larvae are eradicated. Your veterinarian may also ask you to come back after a couple of weeks and get your pet checked to confirm whether or not the treatment was effective. If not, they may prescribe your pet a new anthelmintic medication.
How Can It Be Prevented?
It’s common for pets to appear healthy despite a Strongyloides stercoralis infection. By the time symptoms develop, the threadworms will have already done a lot of damage. The only surefire way to make sure your pet is parasite-free is to keep up with regular vet visits and check-ups. That way, any developing infection can be detected and treated early.
In the household, you can protect yourself and your pet from contracting Strongyloides stercoralis by always keeping your home environment clean and free from animal feces. According to MSD Vet Manual, cleaning potentially contaminated surfaces and objects using steam, salt, or concentrated lime solutions and rinsing them with hot water is effective in killing Strongyloides stercoralis.