Strongyloides Infection in Lizards: Intestinal and Respiratory Parasites

Strongyloides infection is a parasitic worm problem caused by tiny nematodes in the rhabdiasid group. In lizards, these parasites are most associated with the intestinal tract, but larval stages may also involve the lungs and trachea. That is why some reptiles show digestive signs, some show breathing signs, and some show both.

A low parasite load may cause few or no outward symptoms, especially in otherwise stable animals. Trouble starts when parasite numbers rise, the lizard is stressed, or husbandry problems weaken the immune system. Young, newly acquired, wild-caught, imported, or overcrowded lizards may be at higher risk.

Strongyloides is not something you can confirm at home by looking at stool alone. Many reptiles with internal parasites look vague and "off" rather than dramatically sick. If your lizard has appetite loss, weight loss, diarrhea, or noisy breathing, your vet can help sort out whether parasites are part of the problem.

Lizards pick up internal parasites through exposure to contaminated feces, contaminated enclosure surfaces, or infected feeder items and environments. In multi-reptile collections, one infected animal can expose others if quarantine and sanitation are inconsistent. Newly acquired reptiles are a common source of parasite introduction.

Stress and husbandry problems often make infection harder to control. Overcrowding, poor hygiene, incorrect temperatures, chronic dehydration, and poor nutrition can all reduce a lizard’s ability to tolerate or clear parasite burdens. A parasite level that causes little trouble in one animal may cause major illness in another.

There is also an important wrinkle in reptile fecal testing: sometimes a lizard passes parasite material from prey rather than from a true infection. These are called pseudoparasites. That is one reason your vet may recommend repeat testing, correlation with symptoms, and treatment only when the findings fit the whole clinical picture.

Diagnosis usually begins with a full reptile exam, weight check, husbandry review, and microscopic evaluation of a fresh fecal sample. Your vet may use direct smear and fecal flotation, and in some cases may pursue larval testing when a parasite that sheds larvae is suspected. Fresh samples matter because parasite stages can degrade quickly, and intermittent shedding can cause false negatives.

If your lizard has breathing signs, your vet may also recommend chest imaging, cytology, or other respiratory testing to look for pneumonia, secondary bacterial infection, or another cause of respiratory distress. Parasites are only one possible explanation for wheezing or open-mouth breathing in reptiles.

Because not every positive fecal result needs the same response, your vet will interpret the test alongside species, symptoms, body condition, and enclosure history. Repeat fecal checks after treatment are often recommended to see whether parasite numbers have dropped and whether more care is needed.

Prevention starts with quarantine. Any new lizard should be housed separately before joining an established collection, with fecal testing during the quarantine period. This helps catch parasites before they spread through shared tools, hands, décor, or enclosure surfaces.

Good sanitation matters every day. Remove feces promptly, disinfect enclosure items on a regular schedule, and avoid moving bowls, hides, or substrate between reptiles without cleaning them first. Wash your hands after handling reptiles, feces, feeders, or enclosure contents.

Husbandry also plays a major role. Correct temperatures, hydration, UVB when appropriate, species-appropriate nutrition, and reduced crowding help support the immune system and lower the chance that a mild parasite burden becomes a serious illness. Routine wellness exams and periodic fecal checks with your vet are one of the most practical ways to catch internal parasites early.