Poster Presentation 64th International Conference of the Wildlife Disease Association 2015

Do introduced nematodes pose a risk to endemic birds in New Zealand? (#127)

Maurice Alley 1 , Nicki van Zyl , Ellen Schoener , Isabel Castro , Brett Gartrell
  1. Wildbase, Massey University, Palmerston North, Manawatu-Wanganui, New Zealand

Helminth parasites have not been widely studied in wild endemic birds in New Zealand and heavy infections are generally only a winter problem in juveniles undergoing nutritional or environmental stress. However, when native bird habitats are shared with introduced species, some endemic avian species may be exposed to introduced nematodes to which they are not well adapted resulting in pathogenic infections..

Ground feeding birds such as saddlebacks (Philesturnus carunculatus) and kiwi (Apterynx sp) appear to be particularly prone to these infections probably because of their consumption of invertebrates found on the forest floor which are often intermediate hosts to nematodes. More than 10 cases of intestinal perforation and an associated severe fibrinous peritonitis due to migrating Porrocaecum sp have been seen in North Island saddlebacks obtained from three different populations located on Tiritiri Matangi Island, Mt Bruce and Karori/Zealandia wildlife santuaries where they have been breeding successfully for the past 10 years. Introduced birds such as starlings (Turdus vulgaris) frequently flock in trees near the saddleback habitats.

 Migrating ascarid larvae have been found to cause of visceral larval migrans in 12/232 (5.2%) of brown kiwi in which the liver, lung and heart were examined histopathologically. Neural larval migrans was found in 6/101(5.9%) of brown kiwi.  Infection rates in some populations could be higher than this as most kiwi mortalities are due to predation and the brain and viscera from such cases are not routinely examined histopathologically.  PCR analysis was completed on some archived infected tissues using specific Toxocara primers but the results showed no evidence of infection with either T.cati or T.canis