Parasite Immunology. 2019;00:e12673. wileyonlinelibrary.com/journal/pim | 1 of 7 https://doi.org/10.1111/pim.12673 © 2019 John Wiley & Sons Ltd 1 | INTRODUCTION Demodex mites are presumed to be saprophytic parasites of the mammalian skin, and animals including humans are usually carriers without any clinical signs of demodicosis. 1 The two Demodex species in humans, Demodex folliculorum and D brevis, are found ubiquitously in all human races without gender preference, but rarely in newborn and infrequently in children that suggests the main transmission is via physical contact. 2,3 D folliculorum is primarily found as a clus‐ ter in the hair follicle and is the predominant type in the face area, while D brevis possesses more wider distribution on the human body and found in the sebaceous gland. 2,4 In contrast, among the three Demodex species found in dogs, while the habitat of D canis and D injai are hair follicles and sebaceous glands, D cornei inhabits in stratum corneum of epidermis. 5,6 There have also been reports doc‐ umenting cross‐infections between humans and animals; however, the reliability of these rare case reports remains to be verified, due to the polymorphism reported in D canis and D folliculorum. 7‐9 Clinical manifestations of demodicosis differ between humans and dogs; while it is not life‐threatening in former, latter can suffer from fatal consequences. Nevertheless, since there is a close genetic relationship between D folliculorum and D canis, and demodicosis is highly prevalent in certain dog breeds while it is rarely reported in laboratory mice, dog studies are thought to provide valuable insights Received: 15 July 2019 | Revised: 11 September 2019 | Accepted: 23 September 2019 DOI: 10.1111/pim.12673 REVIEW Immune mechanisms in human and canine demodicosis: A review Umut Gazi 1 | Aysegul Taylan‐Ozkan 1,2 | Kosta Y. Mumcuoglu 3 1 Department of Medical Microbiology and Clinical Microbiology, Faculty of Medicine, Near East University, Nicosia, Cyprus 2 Department of Medical Microbiology, Faculty of Medicine, Hitit University, Corum, Turkey 3 Parasitology Unit, Department of Microbiology and Molecular Genetics, The Kuvin Center for the Study of Infectious and Tropical Diseases, Hebrew University‐ Hadassah Medical School, Jerusalem, Israel Correspondence Umut Gazi, Department of Medical Microbiology and Clinical Microbiology, Faculty of Medicine, Near East University, Near East Boulevard, Nicosia, Cyprus. Email: umut.gazi@neu.edu.tr Abstract Demodex mites are saprophytic parasites of the mammalian skin, mostly found in or near pilosebaceous units of hairy regions. While they can be found in healthy hu‐ mans and animals without causing any clinical manifestations, they were suggested to create pathogenic symptoms when they appear in high densities under favourable conditions (ie, demodicosis). Nevertheless, their role as the primary causative agent of the pathogenic conditions in humans is debated today. Canine demodicosis, which is highly prevalent in certain dog breeds, provides a valuable tool for studying the pathogenesis of human demodicosis. Canine and human demodicosis are caused by different Demodex species, and the clinical manifestations in former could be life‐ threatening. Nevertheless, current literature suggests similar immune responses and immune evasion mechanisms in human and canine demodicosis; cellular immunity appeared to have a central role in protection against demodicosis, and Demodex mites were shown to influence both innate and adaptive immune response to escape immune attack. The aim of this review is to summarize the relevant literature on de‐ modicosis obtained from studies conducted on both organisms, and draw the atten‐ tion to the effect of mite‐associated factors (eg, microbiota) on the different clinical manifestations displayed during human and canine demodicosis. KEYWORDS canine, cell‐mediated immunity, Demodex folliculorum, human, humoral immunity, immune evasion