What are Pentastomes?
Various species of lizards can be intermediate or definitive hosts of the pentastomes parasite, also referred to as tongue worms or linquatulids. For many species of pentastomes, the life cycle is unknown, but in some, the life cycle is a long process. Adult female pentastomes can lay millions of eggs in the lungs of its host over a long period of time. The eggs are then passed with fluids into the mouth or the digestive tract of the host, where they are expelled out through urine, feces, or when the host lizard takes a drink. Once another lizard consumes them, they develop into larvae. This intermediate host is then consumed by the definitive host lizard, and the larvae then migrate from the gastrointestinal tract into the bloodstream, and then the lungs. Here, they feed on the host’s blood and grow into mature adults, ready to lay eggs and continue the cycle.
Pentastomes are worm-like parasites that can live in the internal organs and tissues of lizards and other reptiles. Found worldwide, pentastomes can infect many species of lizards, including geckos, skinks, monitors, bearded dragons, agamas, chameleons, and other species. Pentastomes use hooks near their mouth to feed on the blood in the lungs of their hosts, though they can infect other organs, causing varying symptoms of pneumonia, skin swelling, organ dysfunction, and death. A severe infestation of pentastomes is called pentastomiasis or porocephalosis.
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Symptoms of Pentastomes in Lizards
In many lizards infected with pentastomes, there are often no clinical signs noticed by owners. In some cases, though, pentastomes may cause significant tissue damage, resulting in symptoms that are often related to the lungs where the parasites generally live and feed, and which can lead to death in both intermediate and definitive hosts. They can also damage other organs. Symptoms include:
- Labored breathing
- Blood tinged saliva
- Airway obstruction
- Bulging of the overlying skin
- Progressive to chronic bacterial or fungal pneumonia
- Septicemia, or blood poisoning
- Various organ dysfunction
Causes of Pentastomes in Lizards
The cause of a pentastomid infestation is the ingestion of eggs or larvae of the parasite. This can occur through:
Ingestion of saliva, mucus, urine, or feces containing pentastomid eggs from an infected host
Ingestion of an infected lizard, bird, or mammal that harbors pentastomid larvae
Accidental infection from a human handling infected animals, then handling healthy ones
Research has shown that captive lizards are more susceptible to an infestation than wild ones, due to a few factors. In the wild, parasites often cohabitate with their hosts without any problems, but in captivity, there are increased numbers of parasites, as well as many more opportunities for them to spread in small, confined spaces. Other environmental factors can contribute as well, such as overcrowding of animals, poor sanitation, and improper nutrition, temperature, and light. Stressed lizards often develop a suppressed immune system, which can increase opportunities for secondary infections to occur.
Diagnosis of Pentastomes in Lizards
Since there is often an absence of symptoms with this condition, pentastomiasis can only be diagnosed by a direct observation of the pentastomid parasite, either as adults or eggs. There are a number of ways this can be accomplished. The eggs contain a long, oval, tailed larva with four legs bearing pincer claws, and can be found through microscopic examination of tracheal and cloacal washes, and fecal samples. X-rays of respiratory tissues can detect the presence of adult parasites, as can surgical or endoscopic examination of those areas. Veterinarians also look for the presence of hemorrhaging and inflammation of the pulmonary tissues, and blocked airways.
In stressed or dying lizards, pentastomida have been seen to crawl out of their hosts, which could also be a diagnosing observation.
Treatment of Pentastomes in Lizards
Treatment of pentastomes is usually only recommended in lizards showing severe symptoms. Antiparasitic drugs, such as Ivermectin, can be used, but although it reduces the shedding of eggs, it is often insufficient to eliminate the parasites. Additionally, secondary bacterial infections can be caused by rotting pentastomida left inside the lungs. Endoscopic or surgical removal of the pentastomes is the most effective treatment, but can be dangerous in smaller lizards. Additional supportive care is often needed in the form of diet, fluid therapy, and antibiotics to prevent gastrointestinal issues and secondary infections.
Your veterinarian will also discuss diet and dietary sources, basic hygiene, and quarantine practices to ensure a safer recovery, and to reduce the spread of the parasites.
Recovery of Pentastomes in Lizards
There is currently a lack of research on the survival of lizards suffering from a pentastomes infestation. Your veterinarian should discuss with you a recovery outlook for your lizard’s specific case.
Prevent your lizard from acquiring pentastomes by following a few guidelines:
- Have your veterinarian examine any new lizard you acquire for signs of a pentastome infestation
- Practice good hygiene by wearing gloves when handling lizards, washing hands thoroughly after handling lizards, and disinfecting any surfaces that have had contact with lizards
- Feed your lizard only captive-bred insects
- Ensure your feeder insects do not have contact with wildlife feces