Lung flukes, Hematoloechus sp., are pesky little parasites. Up to 89 species of lung flukes have been identified to date. Their life cycle includes two intermediate hosts, the first of which are freshwater snails that swallow fluke eggs. After ingestion, the eggs hatch and produce a larval form of the parasite called cercaria, which are shed from the snails and taken up by damselflies or dragonflies. These are quite the delicacy for frogs and toads who unsuspectingly ingest the infested insects and become the unwitting “host” to these sneaky parasites. Once inside their final host, they migrate from the esophagus to the lungs over the course of about 5 days – gross!!
A recent study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology studied wild-caught North American leopard frogs (Rana pipiens) that either were either parasite-free, carried parasites that had not yet attached to their lungs, or those in which the parasites had already attached to examine how they affected the physiology of their host.
They found that leopard frogs carrying these parasites show signs of immune system activation, weight loss, heart rate variability, reduced blood clotting time and hematocrit, in addition to edema of the lungs and abdomen. Interestingly, some of the leopard frogs appeared to have developed a mutually beneficial symbiotic relationship with the parasites. Those with attached parasites had less edema and showed signs of anti-inflammatory effects in the vasculature while at the same time, the parasites benefited by obtaining nutrients from the host.
Scientists are hoping to learn more about the anti-inflammatory and pro-inflammatory effects of these parasites to develop treatments for inflammatory diseases including obesity, asthma, cancer, arthritis, and heart disease.
Source:
DA Williams, MH Flood. Hematoloechus sp. attachment shifts endothelium in vivo from pro- to anti-inflammatory profile in Rana pipiens: evidence from systemic and capillary physiology. American Journal of Physiology – Regulatory, Integrative and Comparative Physiology. 325(2): R133-R153, 2023.
Categories: Illnesses and Injuries
Tags: American Journal of Physiology, American Physiological Society, fluke, frog, parasite, rana pipiens
Life Lines by Dr. Dolittle 
