Parasites and diseases of the auks (Alcidae) of the world and their ecology - A review

We reviewed all the organisms that are known to parasitize auks (Aves: Alcidae). Of the 23 extant auk species, parasites have been described from 19 species; no published information was found on parasites of Xantus's Murrelet Synthliboramphus hypoleucus, Craveri's Murrelet S. craveri, the Japanese Murrelet S. wumizusume or the Long-billed Murrelet Brachyramphus perdix. Our survey identified 184 taxa parasitic or pathogenic on auks. Endoparasitic microorganisms included 21 viruses, 13 bacteria, 3 dinoflagellates, 6 protozoa and 3 fungi. Other endoparasitic organisms included 57 platyhelminth (34 digenean, 23 cestode), 9 acanthocephalan and 22 nematode taxa. Ectoparasites (all arthropods) included 2 pentastomid, 14 acari and 30 insect taxa. We reviewed published information on the effects that these parasites have on the biology of auks. Most studies did not investigate relationships between the ecology, the breeding condition or the physiologic state of the birds and the presence of parasites. Even though episodes of mass mortality of seabirds are periodically recorded, few of those episodes have been exclusively linked to parasitic infestations. Viral isolates from auks have been recorded from several breeding colonies, but their epizootiologic consequences are unknown. Bacterial isolates, of which the most noteworthy species is the Lyme disease-causing agent Borrelia burgdorferi (sensu lato), have been recorded in auks and their tick ectoparasite Ixodes uriae. A few life cycles of digeneans and cestodes recorded from auks have been determined. Growing evidence indicates prey switching by auk species alters their endoparasitic fauna. Ectoparasitic organisms often play a role in transmitting endoparasites and may affect the reproductive success of their hosts. Some links have been clearly established; many others are only implied and urgently need close attention. The role of parasitism in host population dynamics and as reservoirs is discussed in the context of seabird ecology as a whole