Research Output
Ferlavirus-related deaths in a collection of viperid snakes
  Between June and October 2013 26 snakes of six viperid species kept in two adjoining rooms died (n = 16) or were euthanized on medical (1) or welfare grounds (9). Two were from the main zoo collection, but the other 24 had been imported and quarantined for a minimum of six months. Four of those that died and the single snake euthanized on medical grounds showed minor signs of respiratory disease prior to death and five were weak, lethargic and/or poor feeders. Frequent post mortem findings among all snakes were poor body condition (18) and respiratory disease (13). Seventeen cases were examined histologically and pneumonia, sometimes with air sacculitis and/or tracheitis, was present in 15 individuals. Lung samples from 24 snakes were ferlavirus polymerase chain reaction (PCR) positive, and one of the two snakes for which only liver was available was also positive. The negative liver samples was from a snake that died of sepsis following anaesthesia for surgical removal of a spindle cell sarcoma. Correlation with ante mortem PCR testing of glottal and cloacal swabs in five cases was poor (sensitivity = 40%). Immunohistochemistry (IHC) for ferlaviruses on the tissues of 13 PCR-positive cases showed positive labelling in seven only. Tissues samples from 22 ferlavirus PCR-positive snakes were examined for Chlamydia species by PCR and nine were positive, although DNA sequencing only confirmed two out of three tested as C.pneumoniae. Immunohistochemistry for C.pneumoniae of seven cases (two Chlamydiales PCR positive, one of which was sequenced as C.pneumoniae, plus five negative) confirmed the Chlamydia PCR results.
These two Chlamydiales PCR and IHC positive snakes were ferlavirus PCR positive, but IHC negative suggesting that, even though a ferlavirus was the predominant cause of the outbreak, in a few cases death may have been due to chlamydiosis with ferlavirus present, but not acting as the primary pathogen.

  • Type:


  • Date:

    31 December 2018

  • Publication Status:


  • DOI:


  • ISSN:


  • Library of Congress:

    QL Zoology

  • Dewey Decimal Classification:

    590 Animals (Zoology)

  • Funders:

    Scottish Government


Flach, E. J., Dagleish, M. P., Feltrer, Y., Gill, I. S., Marschang, R. E., Masters, N., …Wheelhouse, N. M. (2018). Ferlavirus-related deaths in a collection of viperid snakes. Journal of Zoo and Wildlife Medicine, 49(4), 983-995.



Epizootic, Chlamydia, ferlavirus, ophidian paramyxovirus, quarantine, viperids.

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