Comparative Parasitology 68(2) 2001 - Peru State College

RESEARCH NOTES 275
Figure 1. Cephalic end of the lung nematode Heterostrongylus heterostrongylus from the Virginia opossum
Didelphis virginiana. Male, frontal view. SEM. Am = amphid; Cl = collarette; Cp = cephalic papilla;
L = lip; M = mouth opening; R = ring surrounding mouth. Scale bar = 20 u,m.
ed D. hayesi from the Virginia opossum from
Sacramento County in northern California. The
objective of our study was to determine the identity
and prevalence of lung parasites in feral Virginia
opossums from southern California.
Thirty-one Virginia opossums from San Diego
County, California, killed by cars or euthanized
after trauma, were examined for lung parasites
from March 1999 to June 2000. All samples
were obtained from a local nonprofit organization,
Project Wildlife, Opossum Team,
members of which also carried out the necropsy
of the animals. All specimens were categorized,
on the basis of weight, into juveniles (0.14-0.90
kg) or adults (1.2-3.4 kg). The lungs with attached
trachea of 7 juveniles and 24 adults were
examined grossly and under the dissecting microscope.
The trachea, bronchi, and bronchioles
were split, and the lung parenchyma was teased
apart gently. Worms recovered were fixed in 5%
formalin or alcohol-formalin-acetic acid (AFA).
For light microscopy, worms were examined as
temporary whole mounts in glycerine after
clearing in glycerine-alcohol with a Diastar®
microscope equipped with a Photostar® camera
system and were measured in micrometers. For
scanning electron microscopy (SEM), the specimens
were postfixed in 1% osmium tetroxide,
followed by dehydration in an ethanol series,
critical point dried with liquid CO2, sputter coated
with gold-palladium, and examined with a
Hitachi S-2700® scanning electron microscope.
Voucher specimens of nematodes were deposited
in the H. W. Manter Laboratory of Parasitology,
University of Nebraska State Museum, Lincoln,
Nebraska, U.S.A. (accession numbers
15617-15619).
In all, 7,381 lungworms were found in adult
and juvenile animals examined. The parasites
were identified as metastrongyloid nematodes.
Of these, 91.1% were identified as D. hayesi and
8.9% were identified as Heterostrongylus heterostrongylus
Travassos, 1925. This is the first
record of H. heterostrongylus from D. virginiana
and the first record of this nematode in
North America. Previous records of H. heterostrongylus
were from another species of opossum,
Didelphis marsupialis Linnaeus, 1758,
Copyright © 2011, The Helminthological Society of Washington