PURDUE    _,    ,
verermofy medical
VOLUME 7, NUMBER 2
SUMMER-FALL 1981
Research on Raccoon Roundworms
Health Implications for A nimals and Humans
Visceral larva migrans (VLM) is a condition in animals, including man, caused by
the migration of roundworm larvae in the
internal tissues. When the larvae get into
the eyes, the condition is known as ocular
larva migrans (OLM). Dog and cat roundworms (Toxocara cant's, T. cati) are well
known causes of VLM and OLM in humans, and it is becoming evident that
other roundworms may also be involved.
Members of the genus Baylisascaris, common intestinal roundworms of raccoons,
skunks, weasels, badgers, etc., are being
implicated. Research at Purdue on Baylisascaris procyonis, the raccoon roundworm, has indicated that: 1) the parasites
are common in urban and rural raccoons;
2) they cause VLM in domestic and wild
animals; 3) they can be extremely pathogenic, often causing fatai central nervous
system disease, and 4) they pose a potential threat to human health in situations
where humans may contact raccoon fecal
contamination.
Encysted larvae,
-- CNS larvae, ocular larvae
Adult ascarid
raccoon
CNS     \  .
disease    X,
I
Approximately
3-4 weeks
Ingested by mice
\*mr\r\r*V\t • «[•«"»     iff *-»
(including man)
Second stage
larva infective
IbUtdm
1961 Pu'Oue Researc
Life cycle of Baylisascaris procyonis as currently understood.
B. procyonis larva recovered from the
brain of a chicken with naturally occurring CNS disease.
Research at Purdue on the raccoon roundworms is being directed by Dr. Kevin R.
Kazacos of the School of Veterinary Medicine, with the cooperation of Dr. Fred H.
Montague of the School of Agriculture,
and others. It is supported by the U.S.
Department of Agriculture, the  Indiana
Department of Natural Resources, and
the National Wildlife Federation. Investigations include: 1) natural VLM outbreaks, 2) pathogenesis and pathology of
the disease, with emphasis on the nervous
system and the eye, 3) a study of the host
range of animals affected and the behavior of the parasite in them, 4) bionomics
of the parasite in urban and rural raccoon
populations, 5) life cycle and development of the parasite in the raccoon, and
6) immunology and serologic diagnosis
which should prove important in assessing
human exposure.
Natural infections of B. procyonis with
severe clinical manifestations have been
documented   in  chickens, quail, rabbits,
woodchucks, squirrels, and an emu. Some
animals were originally suspected of being
rabid.
In the laboratory, fatal nervous system
disease has been observed in mice, rats,
hamsters, chipmunks,grey squirrels, wood-
chucks, ferrets, chickens, ducks, and two
species of monkeys following oral inoculation with infective raccoon ascarid eggs.
Severe eye disease (OLM) was characteristic in the monkeys and preceded or coincided with the nervous manifestations. The
high degree of primate susceptibility indicated the potential importance of the parasite to human health. Cats, dogs, and
swine were resistant to infection, as migra-
B. procyonis larva in the brain of an experimentally infected monkey.
tion was slight or limited in these species.
Ecological studies, including live trapping,
ear tagging, and radiotelemetry, have
shown that raccoons are common in both
urban-residential and rural areas and that
they migrate extensively. They are also
commonly infected with B. procyonis.
Defecation sites ("latrines") were common in natural habitats. Of several hundred fecal deposits collected, about one-
third contained Baylisascaris eggs, closely
paralleling the inrirlpnr.R of rhp parasite
found in the raccoons. It is concluded that
human contact with raccoons and raccoon
feces constitutes a potential for human
infection. The potential danger of keeping
raccoons as pets, especially the young,
without having them examined and de-
wormed should be recognized. The Center
for Disease Control in Atlanta is currently
cooperating in an effort to determine the
extent of human infections. A medical
journal recently reported two cases of
OLM in humans (one from Ohio and one
from Michigan) in which the cause was
not conclusively determined. In both
cases, the size of the ocular larvae coincided with the size of raccoon ascarid larvae from the brain and eyes of animals,
and, in one case, the person had pet raccoons. This finding represents an important observation in the puzzle of Baylisascaris, raccoons, and animal and human
health, and adds substance to the predictions developed from the research efforts
on this campus.
K.R. Kazacos, D. V.M., Ph.D.
Hovde Award Winner
VM Faculty Member Receives Tenth A ward
The most critical element in the functioning of any organization is its personnel. No place is this more evident
than in academia, where there is a direct relationship between the quality of the institution and the quality of its
faculty. Purdue University's School of Veterinary Medicine has a quality faculty.
Upon the retirement of President Frederick L. Hovde
from the University, the Indiana Farm Bureau Federation established the Frederick L. Hovde Award for Excellence in Educational Service to Rural People in
Indiana. Our own Dr. Donald P. Gustafson (OSU'45),
professor of virology in the Department of Veterinary
Microbiology, Pathology, and Public Health, was the
tenth recipient of this award. It was presented during the
annual convention of the Indiana Farm Burca, Inc. and
the Indiana Farm Bureau Cooperative Association, Inc.
He was cited for his contributions to the knowledge of
virus diseases in animals, especially swine, with particular
emphasis on hog cholera and pseudorabies. His ability to
keep in touch with conditions and needs at the "field
level" while working in the laboratory on such fundamental concepts as virus propagation, latent infections,
slow-virus replication, and virus identification is particularly noteworthy. Congratulations, Dr. "Gus"....wc arc
all proud of you.
J.J. Stockton
The tenth Hovde Award for Excellence in Educational
Service to Rural People of Indiana is presented to Dr.
Donald P. Gustafson by dean of agriculture. Dr. B.J.
Liska. An approving Mrs. Gustafson and Dean Stockton
look on.