Lizard Endoparasites

Introduction

Gastrointestinal parasites are commonly seen in reptiles brought into a veterinary hospital, particularly in imported and wild caught specimens. Reptiles can serve as both definitive and intermediate hosts for several species of parasites. However, the ones which cause the most concern to veterinarians are nematodes, trematodes, cestodes, and protozoans, for whom lizards are definitive hosts, leading to shedding of the parasites through the gastrointestinal tract.

Endoparasites

• Protozoa: amoeba, coccidia, flagellates (Hexamita, Trichomonads, Giardia and Leptomonas), ciliates.
• Metazoan parasites: nematodes, cestodes

Nematodes are frequently encountered during routine fecal examinations . The most common parasites is the pinworm (e.g., oxyurids) which are usually nonpathogenic. However, heavy burdens may lead to clinical disease. Furthermore, oxyurids have a direct life cycle and can reach high numbers within the colon, particularly in herbivorous iguanids, putting the lizard at high risk for impaction.

Clinical signs

Clinical signs of amoebiasis include anorexia, pica, prolapse, regurgitation, wasting, dehydration, constipation, weight loss, and lethargy. However as the parasite colonizes the animal's organs, such as the liver and kidney, it may cause necrosis and abscess formation.

Diagnosis

Routine faecal examinations and worming should be part of a standard quarantine procedure or part of regular examinations.

Prevention

Quarantine all new reptiles in separate areas for at least three months. Perform regular veterinary examinations, screens and faecal testing during quarantine and at regular intervals. Record normal patterns of eating, defaecating, weight gain and behaviour for each individual. Provide optimum species-specific husbandry.

Treatment

Any parasite found in captive reptiles should be treated, especially those with direct life cycles, since the stress of captivity can weaken the immune system. Poor husbandry facilitates the build up of direct cycle parasites and parasitised lizards have a shorter life span and tend to be more susceptible to disease.

Flagellates

• Metronidazole PO, repeat in 2 weeks

Coccidia

• Sulphadiazine, sulphamerazine, sulphamethazine PO daily for 21 days, recheck faeces in 3 weeks
• Trimethoprim/sulphamerazine daily for 2 doses, then every second day for 3 weeks, recheck faeces in 3 weeks

Nematodes

• Ivermectin PO or SC, repeat in 2 weeks
• Oxfendazole PO
• Fenbendazole PO, repeat fortnightly until negative faecal examination
• Levamisole ICo, repeat in 2 weeks

Cestodes

• Praziquantel IM once