www.revistabionatura.com Bionatura Issue 4 Vol 8 No 1 2023 Effect of Parasite Infection on the Lipid Profile and Thyroid Hormones in thyroiditis patients Yasamin Ghassan Saeid 1 , Sabaa Taher Mohammed 2 and Luma Qasim Ali 3, * 1 Department of Biology, Al-Farabi University College (FUC), Baghdad, Iraq 2,3 Biology Department, College of Science, Mustansiriyah University * Correspondence: luma7878@uomustansiriyah.edu.iq Available from: http://dx.doi.org/10.21931/RB/CSS/2023.08.04.19 ABSTRACT This study investigated parasitic infection's effect on the thyroid gland's functions by hypo- or hyperthyroidism and inflammation by measuring some physiological and immunological indicators. 130 blood and stool samples were collected from both genders, including 80 samples from people with thyroid disorders and 50 samples from healthy people. Hormone levels and Lipid profile were estimated by using the Cobas e411 device. The general stool examination was conducted to confirm the presence of a parasitic infection and determine the type of parasites. As for the type of parasites found, the most affected were Entamoeba histolytica, Giardia lamblia, Blastocystis hominis, and the last parasite, Cryptosporidium. Hormonal tests, and depending on the level of hormones, it was found that 44 out of 80 patients showed a decrease in hormone levels, which were counted as hy- pothyroidism. In contrast, 36 showed an increase and were counted as hyperthy- roidism. The results of cholesterol level, triglycerides and low-density lipoprotein for hypothyroidism showed an increase in patients without parasites, higher than those parasitic infected compared to the control. Conclusion: This study showed that infection with a parasite affected the performance of the thyroid gland. Keywords: Parasites; Thyroid Disorders; Thyroid Hormones; Lipid Profile. INTRODUCTION Parasites are microscopic creatures that live in or on another organism, receiving their food from the host and inflicting harm 1 . The parasite can attack different organs, for example, the thyroid gland, which is one of the most important endo- crine glands in the body, as its hormones (T4 and T3) have an important role in regulating the body's basic metabolic rate, the generation of heat, contribute to fat metabolism by stimulating lipolysis, and production fatty acids as an energy source 2 . The thyroid is a bi-lobed gland, often described as resembling a butterfly or bow tie. It is positioned in the neck, between the Cervical 5 (C5) and thoracic 1 (T1) vertebrae, just below the thyroid cartilage (Adam’s apple) of the larynx 3 , which