ACLAD NEWSLETTER Vol. 16, No. 1
American Committee on Laboratory Animal Diseases
Spring 1995
Editor: Stephen S. Morse, Ph.D.
The Rockefeller University 1230 York Avenue, Box 2
New York, NY 10021-6399
Telephone: (212) 327-7722 FAX: (212) 327-7974
e-mail: morse@rockvax.rockefeller.edu
For: Items for the Newsletter, general comments
Editorial Assistant: Joan Bailie
Section of Comparative Medicine
Yale University School of Medicine
333 Cedar Street, P.O. Box 3333
New Haven, CT 06510
Telephone: (203) 785-2507 FAX: (203) 785-7499
For: Changes of address; questions about mailing or dues
ACLAD Officers 1995:
PRESIDENT
Robert O. Jacoby
VICE-PRESIDENT
John D. Strandberg
TREASURER
Diane J. Gaertner
SECRETARY
Stephen S. Morse
COUNCILLORS
Joseph E. Wagner Kim Waggie =================================================
TENTATIVE ANNOUNCEMENT:
ACLAD SCIENTIFIC PROGRAM: Tuesday, October 17, Baltimore, 8 A.M.--Noon
Seminar: Rodent Parvovirus Infections WALLACE P. ROWE LECTURER: Donald E.
Mosier, PhD, MD (Tentatively, as of this writing, the Business Meeting will
also be held on Tuesday, after the W.P. Rowe Lecture)
=================================================
CONTRIBUTORS THIS ISSUE:
Stephen D. Miller, Pathogenesis of Theiler's Murine Encephalomyelitis Virus-Induced
Demyelinating Disease - A Model of Multiple Sclerosis.
I.V. Plakhov, Z. Bi, C. Aoki, and C.S. Reiss, The Earliest Events in Vesicular
Stomatitis Virus Infection of the Murine Olfactory Neuroepithelium and Invasion
of the Central Nervous System.
Benjamin J. Weigler, Felid herpesvirus 1 (FHV-1) in cats: Polymerase chain
reaction (PCR) for diagnosis and molecular epidemiology of FHV-1.
K. Dzeb, J. Woodall, and L. Grady, Hantavirus - Northeast USA (Report on
Northeast Hantavirus Workshop).
NEXT ISSUE OF THE NEWSLETTER: AUGUST 1995. PLEASE SEND CONTRIBUTIONS FOR
THE NEXT ISSUE BY AUGUST 1, 1995. ===========================================
PRESIDENT'S MESSAGE AND ANNOUNCEMENTS
The new constitution and by-laws and slate of officers have been approved
overwhelmingly by the membership. The vote tallies were as follows: Constitution
and Bylaws (For=50, Against=2), Slate of officers (For=60, Against=1). Therefore
the governance and governors for 1995 are in place. The officers are: President
: Robert O. Jacoby, DVM, PhD Vice President: John D. Strandberg, DVM, PhD
Treasurer: Diane J. Gaertner, DVM Secretary: Stephen S. Morse, PhD Councilor:
Joseph E. Wagner, DVM, PhD Councilor: Kim Waggie, DVM, PhD ACLAD SCIENTIFIC
PROGRAM (TENTATIVE) Annual Seminar and Wallace P. Rowe Lecture Tuesday,
October 17, Baltimore 8 A.M.--Noon WALLACE P. ROWE LECTURER: Donald E. Mosier,
PhD, MD Planning is moving ahead for ACLAD programs for the 1995 national
session of AALAS. The Tuesday morning seminar preceding the Rowe lecture
will focus on rodent parvovirus infections. The following presentations
are TENTATIVELY scheduled (as of 5/95): Dr. David G. Besselsen (Univ. of
Missouri): The molecular and cellular biology of rodent parvoviruses - I.
Dr. Lisa Ball-Goodrich (Yale): The molecular and cellular biology of rodent
parvoviruses - II. Dr. Abigail L. Smith (Yale): The immunobiology of rodent
parvovirus infections. Dr. Robert O. Jacoby (Yale): The pathobiology of
rodent parvovirus infections. Dr. Lela K. Riley (Univ. of Missouri): The
diagnosis of rodent parovirus infections. Co-anchors of the seminar are
Drs. Joseph E. Wagner and Kimberly S. Waggie. ACLAD will also sponsor another
trainee luncheon featuring open discusion about opportunities and challenges
for careers in comparative medicine and laboratory animal medicine. Further
details will appear in the next issue of the Newsletter. REDUCED DUES FOR
TRAINEES: In order to encourage trainees to become ACLAD members, a special
rate of $10 per year has been approved for trainees (with certification
of training program director). ==========================================
MINUTES OF THE ACLAD ANNUAL BUSINESS MEETING, 1994 Pittsburgh, Pennsylvania,
Sunday, October 16, 1994 The meeting was called to order at approximately
5:10 P.M. by President Jacoby. The proposed new Bylaws were discussed. The
major changes proposed include separating the functions of Secretary and
Treasurer, and adding the post of Vice-President, who will automatically
become President in the following year. At the meeting, there was discussion
of a number of points, including the possibility of staggering officers'
terms. Changing the membership requirements, so that nomination by a member
in good standing would no longer be required to join, was also discussed.
After discussion, the new Constitution and Bylaws, as amended during the
discussion, were approved for submission to the membership in a mail ballot.
The Nominating Committee presented nominations of officers for 1995, which
were approved by the membership at the meeting. The entire membership will
receive ballots by mail. [NOTE: Since the meeting, the new Bylaws and slate
of officers were approved by membership. See previous page for details.]
Report of the Secretary-Treasurer: Total membership now stands at 420 (including
31 foreign), a slight increase over last year. The financial statement (prepared
by Ms. Joan Bailie) was read by the Secretary-Treasurer. ACLAD's balance
stood at $8,299.56 as of September 30, similar to last year's. As in past
years, it is expected that most of this balance will be required to pay
speakers' expenses and other costs of the annual meeting. Two additional
items were discussed: Suggestions for improving and expanding the Newsletter,
and trainee activities. For the Newsletter, a number of topics of current
interest were discussed. The possibility of ACLAD special topic overview
columns in other journals (either in addition to or in place of some of
the Newsletter content) was also suggested and discussed favorably. At this
year's meeting, a Trainee research session is being added to the program,
as an experiment. From the discussion, it was clear that many members consider
trainee outreach and encouragement an important priority. Research awards
were also discussed, including changes being made by AALAS in their awards.
It was noted that the number of good papers now presented makes it hard
to administer a single award for research. Pravin Bhatt suggested that there
should be two research awards, one for established and one for young investigators.
A Trainees Award was also suggested. After further discussion and announcements
(next year's Rowe Lecturer, in Baltimore, will be Don Mosier, and the ACLAD
symposium will be on Parvoviruses), the Business Meeting was adjourned.
Respectfully submitted, Stephen S. Morse Secretary-Treasurer ==========================================================
**RESEARCH REPORTS**
PATHOGENESIS OF THEILER'S MURINE ENCEPHALOMYELITIS VIRUS-INDUCED DEMYELINATING
DISEASE - A MODEL OF MULTIPLE SCLEROSIS
by Stephen D. Miller
Department of Microbiology-Immunology Northwestern University Medical School,
Chicago, IL
Theiler's murine encephalomyelitis viruses (TMEV) are members of the cardiovirus
group of the Picornaviridae, and are natural pathogens in mice (1). TMEV
is composed of three capsid proteins (VP1, VP2, and VP3) which surround
a single-stranded, plus-sense RNA genome associated with a fourth structural
protein, VP4. TMEV was first isolated in 1937 from a spontaneous case of
paralysis in the mouse colony of Max Theiler (2). TMEV has since been shown
to infect both wild and colony bred mice. There are two subgroups of TMEV.
One group includes GD VII and FA viruses, which grow to high titers, are
highly virulent, and induce fatal encephalitis. The second group known as
the Theiler's original (TO) subgroup includes the Daniels (DA) and BeAn
8386 strains that have low virulence, grow to relatively low titers, but
induce a persistent infection of central nervous system (CNS) white matter
accompanied by extensive inflammatory demyelination (3). Natural encounter
with the TO strains initially leads to enteric infections in mice with a
small percentage of susceptible strains developing a subsequent infection
of the central nervous system (CNS), which can lead to a chronic, progressive
demyelinating disease characterized by spastic hind limb paralysis. The
demyelination is linked to persistent TMEV infection of the CNS, and is
characterized histologically by perivascular mononuclear cell infiltrates
in the CNS and primary demyelination (4).
Mechanistic, histopathologic, genetic, and clinical similarities between
this chronic, virus-induced murine disease and human multiple sclerosis
(MS) make TMEV-induced demyelinating disease an excellent experimental model
for MS (5). Demyelination in both MS and TMEV-induced demyelinating disease
is clearly immune-mediated and thought to be due primarily to the activity
of inflammatory responses mediated via production of pro-inflammatory cytokines
produced by antigen-specific CD4+ T cells. The pathological lesions are
similar, with inflammation and demyelination being closely linked in Theiler's
virus infection as they are in acute MS lesions.
In addition, the cellular nature of the mononuclear infiltrates in both
diseases consists primarily of monocytes, macrophages, and T lymphocytes
(4). Both diseases are under multigenic control; susceptibility is associated
with both major histocompatibility complex (MHC) genes and non-MHC genes,
including T cell receptor genes (6). Lastly, both MS and TMEV infection
of mice lead to chronic and/or relapsing paralytic symptoms. In addition
to the cellular nature of the CNS infiltrates, the involvement of a CD4+
Th1- (type 1 T helper cell) mediated pathologic process in TMEV-induced
demyelination is supported by a variety of experimental data including:
a) correlation of disease susceptibility with the development of chronic,
high levels of TMEV-specific delayed-type hypersensitivity responses and
IgG2a-dominant anti-viral antibody responses (7); b) inhibition of demyelination
in mice treated with monoclonal antibodies directed against MHC class II
or CD4+ T cells (8); c) exacerbation of disease onset in mice given CD4+
T cell clones specific for the immunodominant viral epitope (8); and d)
inhibition of disease induction in mice specifically tolerized to virus
epitopes (9). Relevant to epidemiological studies which strongly support
a possible virus trigger of MS (10), it is significant that chronic demyelination
in TMEV-infected mice is initiated in the apparent absence of autoimmune
anti-myelin responses. Prior induction of tolerance to myelin antigens does
not inhibit the induction of TMEV-induced demyelinating disease, but is
extremely effective at inhibiting experimental autoimmune encephalomyelitis
(EAE) an autoimmune demyelination model of MS (11).
In addition, T cell responses to the two major myelin proteins, myelin basic
protein (MBP) and proteolipid protein (PLP) are not demonstrable early in
the demyelinating process (12). However, we have recently demonstrated that
chronic CNS immunopathology initiated by virus-specific T cells can lead
to neuroantigen-specific immune responses later in the disease course. DTH
and T cell proliferative responses to the immunodominant myelin PLP epitope
(residues 139-151) are demonstrable in mice beginning 7-9 weeks post-infection,
well after the first appearance of clinical symptoms of paralysis which
are first noted 4-5 weeks post infection (13). As there are no apparent
cross-reactive epitopes on TMEV capsid proteins and the major myelin proteins
[MBP, PLP, myelin-associated glycoprotein (MAG) or myelin oligodendrocyte
glycoprotein (MOG)] (12), the late development of anti-myelin responses
in TMEV-infected mice is consistent with a process termed 'epitope spreading'
(13,14).
The epitope spreading hypothesis could explain the sequential development
of T cell reactivity in TMEV-infected mice by the following sequence of
events. Demyelination in genetically susceptible mouse strains is initiated
by virus-specific Th1 cells targeting CNS-resident virus. Chemokines (MIP-1)
and pro-inflammatory cytokines (IFN-gamma, LT/TNF, IL-2) produced by these
virus-specific Th1 cells then lead to the chemoattraction and activation
of peripheral mononuclear phagocytes and activation of CNS-resident astrocytes
and microglia cells which are the primary effector cells for myelin destruction
and also serve as the predominant host cells in which the virus persists.
As a result of the opening of the blood brain barrier during the chronic
inflammatory response and the concomitant release of myelin epitopes to
the periphery, T cells specific for endogenous immunodominant self myelin
epitopes are activated. These autoreactive T cells can then re-enter the
CNS and contribute to the chronic tissue destruction. Epitope spreading
provides an alternative explanation as to how an autoimmune response may
develop secondary to an infectious insult without having to invoke molecular
mimicry (i.e., the presence of a cross-reactive epitope on the pathogen
and on the autoantigen). These results have important potential implications
as to the possible pathogenesis of certain forms of MS and to the development
of antigen-specific therapeutic treatments.
1. Pevear, D. C., J. Borkowski, M. Luo, and H. Lipton. 1988. Sequence comparison
of a highly virulent and a less virulent strain of Theiler's virus. Amino
acid differences on a three-dimensional model identify the location of possible
immunogenic sites. Ann. NY Acad. Sci. 540:652-653.
2. Theiler, M. 1937. Spontaneous encephalomyelitis of mice, a new virus
disease. J. Exp. Med. 65:705-719.
3. Lipton, H. L. 1980. Persistent Theiler's murine encephalomyelitis virus
infection in mice depends on plaque size. J. Gen. Virol. 46:169-177.
4. Dal Canto, M. C., R. W. Melvold, B. S. Kim, and S. D. Miller. 1994. Two
models of multiple sclerosis: Experimental allergic encephalomyelitis (EAE)
and Theiler's murine encephalomyelitis virus (TMEV) infection - a pathological
and immunological comparison. J. Microscopic Res. and Techniques. In press.
5. Dal Canto, M. C. 1990. Experimental models of virus-induced demyelination.
In Handbook of Multiple Sclerosis. S. D. Cook, editor. Marcel Decker, Inc.
New York and Basel. 63-100.
6. Miller, S. D. and S. J. Gerety. 1990. Immunologic aspects of Theiler's
murine encephalomyelitis virus (TMEV)-induced demyelinating disease. Semin.
Virol. 1:263-272.
7. Clatch, R. J., H. L. Lipton, and S. D. Miller. 1986. Characterization
of Theiler's murine encephalomyelitis virus (TMEV)-specific delayed-type
hypersensitivity responses in TMEV-induced demyelinating disease: correlation
with clinical signs. J. Immunol. 136:920-927.
8. Gerety, S. J., M. K. Rundell, M. C. Dal Canto, and S. D. Miller. 1994.
Class II-restricted T cell responses in Theiler's murine encephalomyelitis
virus (TMEV)-induced demyelinating disease. VI. Potentiation of demyelination
with and characterization of an immunopathologic CD4+ T cell line specific
for an immunodominant VP2 epitope. J. Immunol. 152:919-929.
9. Karpus, W. J., J. G. Pope, J. D. Peterson, M. C. Dal Canto, and S. D.
Miller. 1994. Inhibition of Theiler's virus-mediated demyelination by peripheral
immune tolerance induction. J. Immunol. In press.
10. Kurtzke, J. F. 1993. Epidemiologic evidence for multiple sclerosis as
an infection. Clin. Microbiol. Rev. 6:382-427.
11. Miller, S. D., S. J. Gerety, M. K. Kennedy, J. D. Peterson, J. L. Trotter,
V. K. Tuohy, C. Waltenbaugh, M. C. Dal Canto, and H. L. Lipton. 1990. Class
II-restricted T cell responses in Theiler's murine encephalomyelitis virus
(TMEV)-induced demyelinating disease. III. Failure of neuroantigen-specific
immune tolerance to affect the clinical course of demyelination. J. Neuroimmunol.
26:9-23.
12. Miller, S. D., R. J. Clatch, D. C. Pevear, J. L. Trotter, and H. L.
Lipton. 1987. Class II-restricted T cell responses in Theiler's murine encephalomyelitis
virus (TMEV)-induced demyelinating disease. I. Cross-specificity among TMEV
substrains and related picornaviruses, but not myelin proteins. J. Immunol.
138:3776-3784.
13. Miller, S. D., B. L. McRae, C. L. Vanderlugt, K. M. Nikcevich, J. G.
Pope, L. Pope, and W. J. Karpus. 1995. Evolution of the T cell repertoire
during the course of experimental autoimmune encephalomyelitis. Immunol.
Rev. In press.
14. Miller, S. D. and W. J. Karpus. 1994. The immunopathogenesis and regulation
of T-cell mediated demyelinating diseases. Immunol. Today. 15:356-361. ***************************************************************
THE EARLIEST EVENTS IN VESICULAR STOMATITIS VIRUS INFECTION OF THE MURINE
OLFACTORY NEUROEPITHELIUM AND INVASION OF THE CENTRAL NERVOUS SYSTEM
by I.V. Plakhov, Z. Bi, C. Aoki and C.S. Reiss
New York University, 100 Washington Square East, New York, NY
Intranasal application of a rhabdovirus, vesicular stomatitis virus (VSV),
to lightly anesthetized BALB/c mice results in central nervous system (CNS)
infection. Virus can be found in the olfactory bulb as early as 12 hours
post instillation (1). We inferred that virus initially replicated in the
olfactory neuroepithelium and then entered the olfactory nerve (2); VSV
was then transported in a retrograde manner to the olfactory nerve layer
of the olfactory bulb. In order to examine the earliest events in the nasal
turbinates, we have examined both the respiratory and the neuroepithelium
(within the first 12 hours of infection) for evidence of cells infected
with VSV, by immunohistochemistry. The first cell types infected were the
sensory neurons, later adjoining cells in the epithelial alyer were Ag-positive.
Finally, at 24 hours post instillation, the lamina propria was eroded, involving
Bowman's glands and supporting cell types (3).
Surgical ablation of the olfactory bulbs was performed to cut direct olfactory
nerve-to-external plexiform layer neuron transmission. Virus replicated
locally in the nasal neuroepithelium and was transmitted through a novel
free route in cerebral spinal fluid; this resulted in meningitis and encephalitis
not observed in intact mice (3). Studies to determine if there was viral
transmission through the trigeminal nerve (which also innervates the nasal
turbinates) through the ganglion to caudal nuclei were performed. These
CNS nuclei are viral antigen (Ag) positive at very late times in infection,
and are probably infected through regulatory circuits from the hypothalamus.
The trigeminal ganglion remained virus-free throughout the infection and
observation period (3). Co-administration of replication-competent defective
interfering (DI) viral particles with infectious virus resulted in interference
with the infection, probably at the level of the olfactory neuroepithelium.
In the co-infected group, there was delayed entry into the CNS, fewer immunopositive
cells, and both morbidity and mortality, indicators of pathogenesis, were
diminished (4). Thus DI particles can interefere with viral infections of
the CNS.
To understand the mechanism(s) involved in the innate immune response to
VSV, we have studied the role of nitric oxide (NO) during infection of neurons.
NO synthetase (NOS) is an important neurotransmitter in the olfactory bulb,
and is constitutively expressed (cNOS) in neurons there. Another form of
NOS (iNOS) is inducible in cells of the monocyte/macrophage/microglia lineage.
In vitro studies are consistent with a substantial inhibitory activity of
NO on the production of VSV in infected neurons (5). Additional immunohistochemical
studies show the presence and upregulation of cNOS in the olfactory bulb
immediately following invasion of VSV infection (6). Additional preliminary
studies have indicated a protective role of interleukin- 12 (IL-12), administered
parenterally, on the course of infection of the CNS. Approximately 2 log10
less virus was recovered in the brains of mice, 4 days after infection.
The mechanism of this suppression of viral replication is being investigated
(7). During infection, the blood-brain barrier is disturbed (8).
Previous studies in our lab have demonstrated an essential role of both
CD4 and CD8 T cells in restricting viral replication and promoting recovery
from infection (9). Unlike the Sindbis virus infection of mice (10), it
does not appear that antiviral antibody is important in recovery from infection
(6). Thus we have demonstrated a role both for the innate and the specific
immune responses to vesicular stomatitis virus infection of the central
nervous system of the mouse. Future studies will include evaluations of
the role of olfaction, memory and behavior in mice which have recovered
from infection, as well as in depth investigations of innate immunity, cytokines,
and induction of protective immunity with vaccines. [Supported by research
grant AI18083 and a Research Challenge Fund grant from NYU to CSR; and by
an NSF Presidential Faculty Award to CA.]
1. Huneycutt, Plakhov, Shusterman, Bartido, Huang, Reiss, & Aoki, Brain
Res.635:81-95, 1994.
2. Lundh et al., Neuropathol. Appl. Neurobiol. 13:111-122, 1987.
3. Plakhov, Arlund, Aoki, & Reiss, submitted, 1995.
4. Plakhov, Aoki, Reiss & Huang, J. Neurovirology, in press, 1995.
5. Bi & Reiss, J. Virology, in press, April, 1995.
6. Bi & Reiss, in preparation.
7. Huneycutt, Bi, Aoki & Reiss, J. Virology, 67:6698-6706, 1994.
8. Barna, Bi & reiss, in preparation.
9. Quandt, Bi & Reiss, in preparation.
10. Levine, Hardwick, Trapp, Bollinger & Griffin, Science 254:856-860,
1991. *****************************************************************
FELID HERPESVIRUS 1 (FHV-1) IN CATS: POLYMERASE CHAIN REACTION (PCR) FOR
DIAGNOSIS AND MOLECULAR EPIDEMIOLOGY OF FHV-1
by Benjamin J. Weigler
College of Veterinary Medicine, North Carolina State University
Felid herpesvirus 1 (FHV-1), the etiological agent of feline rhinotracheitis,
is one of the most important ocular and upper respiratory pathogens of domestic
cats worldwide. Common clinical signs of infection include depression, fever,
conjunctivitis, chemosis, sneezing and serous nasal and/or ocular discharge.
Excessive salivation and drooling may be apparent in early stages of the
disease process. Oral ulceration is less commonly associated with FHV-1
than with feline calicivirus, which otherwise may present with similar manifestations.
Ocular disease associated with FHV-1 can result in chronic conjunctivitis,
epithelial and stromal keratitis, symblepharon formation, keratoconjunctivitis
sicca, and corneal sequestration. Respiratory infection with FHV-1 causes
necrosis and ulceration of the nasal turbinate mucosa, exacerbated by bacterial
and mycoplasma infections, and is thought to be an important etiology in
chronic upper respiratory disease of cats. Severe respiratory disease from
this agent has been associated with abortions and high mortality of neonatal
kittens, typically in conjunction with dehydration and secondary bacterial
infections including bronchopneumonia. Outbreaks of FHV-1 have been observed
in commercial catteries, laboratory animal facilities, and other multi-cat
environments. Transactivation of feline immunodeficiency virus by FHV-1
has been demonstrated, suggesting a co-factor relationship in feline AIDS.
In addition, FHV-1 represents the only recognized natural animal model for
ocular herpes simplex virus-1 (HSV-1) stromal keratitis of human beings.
Lack of sufficiently sensitive diagnostic assays have precluded complete
epidemiologic assessment and prevention of FHV-1 related conditions in cats.
Primary FHV-1 infection typically occurs in younger cats, and approximately
80% of all cats become infected at some point during their lifetime. Historically,
it has been estimated that half of all FHV-1 infected cats become latent
carriers of the virus, despite the formation of a specific immune response.
Subsequent reactivation and shedding events occur spontaneously or following
various stress stimuli, including group-housing unfamiliar cats, surgery,
pregnancy, lactation, or corticosteroid administration. The primary anatomical
site of latent FHV-1 infection appears to be the trigeminal ganglia, following
ascent of the virus up neuronal tracts from infection in peripheral dermatomes
in the oral-facial epithelium. The phenomenon of latency is extremely important
in the epidemiology of the herpesviruses and can jeopardize successful control
and eradication programs, often at great economic expense. In general, vaccines
for herpesviruses are capable of reducing the severity of primary and recrudescent
disease, but do not prevent primary or latent infections. Latent HSV-1 outside
of neuronal cells in very low copy numbers has been demonstrated in human
beings and in experimentally inoculated rabbits and mice. Reactivation of
HSV-1 from corneal latency in human donors can precipitate a clinical keratitis
indistinguishable from recrudescent infections in cornea recipient patients
and profoundly reduces the success of transplant operations. Similarly,
a recent report has documented non-neuronal sites of FHV-1 latency in cats
during an epizootic of the virus at a laboratory animal facility. Studies
of vaccine and antiviral therapy require consideration of non-neuronal latency,
which has only recently become possible through molecular methodologies.
In response to this need, a single-round (40 cycles) PCR directed at a 322-bp
region in the thymidine kinase gene of FHV-1 was developed. The amplicon
is detected by ethidium bromide staining following 1% agarose gel electrophoresis.
Specificity of the product is confirmed by characteristic cleavage using
Pvu II restriction endonuclease, or by hybridization to a radio-labeled
25-mer oligonucleotide as probe. Development of the PCR followed comprehensive
evaluation of four candidate primer pairs in single-round or nested constructs.
Through serial-titration studies of sucrose-density purified FHV-1 virions,
this PCR has been shown to routinely detect less than 240 FHV-1 genomes
in the context of 1 microgram aliquots of native feline DNA, a sensitivity
approximately 10-fold greater than any previously described diagnostic assay
for the agent. This sensitivity is required for investigations of non-neuronal
latency, whereby the copy number per cell is known to be low. The assay
functions well for clinical swab specimens containing infectious or noninfectious
virus, as well as latent FHV-1 in post-mortem tissue harvests. Modified-live
vaccine strains of FHV-1 are also easily detectable via the PCR. In addition,
a separate PCR has been developed for a 375-bp region in the feline actin
gene, which is used to verify the integrity of DNA template in tissue harvests
which are FHV-1 PCR-negative. The PCR is currently being used for studies
regarding vaccine-latency dynamics of FHV-1 infection in neuronal and non-neuronal
tissues, and for epidemiologic investigations regarding the role of FHV-1
in chronic keratoconjunctivitis and chronic upper respiratory disease of
domestic cats. Colleagues interested in collaborative research regarding
this new diagnostic assay are invited to contact the author for further
information (Telephone: (919) 829-4303, FAX: (919) 829-4336, E-mail: Weigler@sn1.cvm.ncsu.edu).
***********************************************************
GUIDELINES FOR PREVENTING B VIRUS INFECTIONS NOW PUBLISHED
The latest guidelines from the B Virus Working Group, the definitive document
on this important subject, have recently been published: G.P. Holmes and
B Virus Working Group. Guidelines for the Prevention and Treatment of B-Virus
Infections in Exposed Persons. Clinical Infectious Diseases 20:421-439 (1995).
************************************************************
HANTAVIRUS - NORTHEAST USA Report on Northeast Hantavirus Workshop
Sponsored by the New York State Department of Health Held in Albany, NY
on January 31, 1995
by K. Dzeb, J. Woodall, and L. Grady
New York State Department of Health, Albany, NY
On January 31, 1995, the Wadsworth Center, in conjunction with the department's
Center for Community Health, sponsored the Northeast Hantavirus Workshop,
held at the Wadsworth Center's David Axelrod Institute. The objective of
the workshop was to update participants on recent findings on the biology
and epidemiology of hantaviruses. Some 25 academic and public health institutions
were represented among more than 100 attendees from state and county health
departments, federal public health agencies and universities.
The workshop was divided into four sessions: The Virus, National/International
Updates, Northeastern States Update, and Public Health Plans/Priorities.
Speakers included the principal scientists taking part in investigations
of the 1993 virus outbreak in the southwestern U.S. and of a Long Island
student's death from hantavirus pulmonary syndrome (HPS) in Rhode Island
last year. The speakers represented the National Institutes of Health (NIH),
Centers for Disease Control and Prevention (CDC), State University of New
York at Stony Brook, University of Rhode Island, University of New Mexico,
and New York State, New York City and Rhode Island State Departments of
Health.
Taxonomically, the hantaviruses constitute a genus in the family Bunyaviridae;
the RNA genome (as in all bunyaviruses) consists of three segments. Data
presented on the genetic diversity of North American hantaviruses indicated
that the viruses associated with HPS are clearly related to other hantaviruses,
but occupy a separate branch, or grouping, on the evolutionary tree. Evidence
was also presented that these viruses are not "new" agents resulting
from genetic reassortment of distinct subtypes. Rather, it appears that
they are merely newly recognized; the earliest case retrospectively identified
occurred in Utah in 1959. In the U.S., 102 cases of HPS had been reported
(as of January 31, 1995), with a case fatality rate of 52 percent. While
known cases are still clustered predominantly in the Southwest and West,
the disease occurs widely throughout the U.S. and no geographic area appears
to be exempted. Hantaviruses are found essentially worldwide, but until
1993, hantaviruses were not associated with severe respiratory disease (the
classic hantaviral disease, recognized in parts of Asia and Europe, is hemorrhagic
fever with renal syndrome), so this may be a distinctive feature of American
hantaviruses. In all known cases, hantaviruses are zoonotic infections;
rodents have been implicated as the zoonotic reservoir, and spread appears
to be by aerosolization of virus from urine and feces. Thus, unlike many
other bunyaviruses, there is no evidence that insects play any role in transmission.
Animal surveillance study results discussed at the meeting showed that while
HPS hantaviruses have been found in a variety of species, the primary reservoir
appears to be mice of the genus Peromyscus (deer mouse) found throughout
North America.
P. leucopus, the particular species of deer mouse found in the Northeast,
is different from the one found in much of the rest of the United States
(P. maniculatus); the hantavirus (named NY-1) that was identified from P.
leucopus trapped on Shelter Island (Long Island) is also distinguishable
from those hantaviruses found in P. maniculatus. Sera from P. leucopus trapped
in many locations in both New York state and Rhode Island have been shown
to be positive, including sera from retrospective surveys in New York state.
However, these were done using Seoul and Sin Nombre virus antigens, and
it is not known how specific those results are for the NY-1 isolate. Studies
mapping particular antigenic characteristics to two of the three viral genomic
RNA segments were presented, as well as data on the nucleotide sequence
of the viral genome from the fatal Rhode Island/New York case. To ascertain
the distribution and types of hantaviruses in the Northeast, participants
recommended that additional rodent surveys be undertaken, including species
other than the primary reservoir host Peromyscus, and human population surveys,
especially in areas with above average levels of infected rodents, and that
laboratory diagnostic methods be standardized, using the Western blot technique
for confirmation of virus type. **********************************************************
ANNOUNCEMENTS
ANNUAL MEETING, TUESDAY, OCTOBER 17, BALTIMORE: Current tentative plans
call for the Business Meeting and Trainees forum to be held on Tuesday afternoon
(October 17), following lunch (the Seminar and W.P. Rowe Lecture will be
Tuesday morning). Final details will appear in the next issue. Items for
the next issue are cordially invited (by August 1, please)! Sincere thanks
and appreciation to the authors who contributed articles and other items
for this issue of the Newsletter: Stephen D. Miller; I.V. Plakhov, Z. Bi,
C. Aoki, and C.S. Reiss; Benjamin J. Weigler; and K. Dzeb, J. Woodall, and
L. Grady; Ken Boschert; and Robert O. Jacoby. ... Special thanks to Dr.
Carol Reiss (New York University) for help in identifying new potential
contributors ... and special thanks in advance to those contributors whose
work will appear in the next issue.
Contributors in the next issue will include David Hone and colleagues (Salmonella
vaccine vector expressing HIV-1 antigens), and Aron Lukacher (polyoma and
endogenous superantigens). Thanks to Joan Bailie, as always, for her indispensable
help with production of the Newsletter and with membership matters. The
Hantavirus report appears courtesy of the ProMED [Program for Monitoring
Emerging Diseases] E-mail network (Dr. Jack Woodall, List Moderator).
THE NEWSLETTER NOW HAS A MEMBERSHIP/RENEWAL FORM ON THE LAST PAGE OF EACH
ISSUE, FOR NEW MEMBERS AND FOR THOSE WHO MAY WISH TO PAY IN ADVANCE. DUES
NOTICES WILL STILL BE MAILED EACH SPRING AS USUAL. DUES ARE $20 ANNUALLY
($10 FOR TRAINEES, WITH CERTIFICATION OF TRAINING PROGRAM DIRECTOR).
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