West Nile Virus: what ornithologists and bird
banders
should know
Introduction
West Nile Virus (WNV) was first isolated in 1937 in Uganda. There have
been
outbreaks in Israel (1951-1954), France (1962, 2000), and South
Africa
(1974). It appeared in Western Europe in the mid-1990s and traveled to
the
United States in 1999, where researchers – and their universities,
government
research agencies, and other research organizations – became concerned
about
the risk to field biologists, students, and others. Perhaps out of an
abundance
of caution and spurred by constant media attention to WNV, one
university
cancelled field research and field biology classes that involved bird
banding.
The Ornithological Council – a consortium of 11 scientific
ornithological
societies in the Western Hemisphere – consulted with a number of
experts
to compile this fact sheet about the risks of WNV to ornithologists and
bird
banders and to provide the most up-to-date public health
recommendations
for those handling live birds, carcasses, or tissues that are
potentially
infected with WNV.
Understand the risk
All research involves risk. Know the risks and take reasonable
precautions.
West Nile Virus should be no more of a deterrent to ornithological
research
and education than any other risk encountered in scientific research.
According to the Centers for Disease Control (as of 11 April 2003; see
http://www.cdc.gov/ncidod/dvbid/westnile/qa/symptoms.htm)
- Most mosquitoes bites will not lead to a WNV
infection
- Most people who are infected with WNV do not
develop
any type of illness
- It is estimated that 20% of the people who become
infected
will develop West Nile fever: mild symptoms, including
fever,
headache, and body aches, occasionally with a skin
rash on the trunk
of the body and swollen lymph glands.
- About 1 of each 150 infected persons becomes
seriously
ill with central nervous system infection (encephalitis &/or
meningitis)
- About 6.6% of the 4,161 cases of the laboratory-positive
2002 WNV cases in the United States were fatal.
For young/healthy researchers who are not immunocompromised, West Nile
Virus
is unlikely to cause much more than a mild illness – typically
“flu-like
symptoms.” A more serious case of West Nile Virus in humans results in
fever,
disorientation, muscle weakness, neck stiffness, headache, nausea.
Persons
over 50 years of age are at increased risk of severe disease. An
analysis
of attack rates per million persons during the 1999 New York City
outbreak
showed that compared with persons 0 to 19 years of age, the incidence
of
severe neurologic disease was 10 times higher in persons 50 to 59 years
of
age and 43 times higher in those at least 80 years of age.
However,
although older persons are at greater risk for West Nile
Meningoencephalitis
or death, persons of any age might develop severe neurologic disease
(Nash
et al. 2001). CDC recommends that persons with severe or unusual
headaches
seek medical attention as soon as possible.
In the lab
As of February 2003, there have been only two documented cases of
researchers
contracting West Nile Virus in the course of conducting research. Both
cases
involved microbiologists. One was infected from an accidental needle
puncture
in the finger while working with live virus while the other was
infected
through an accidental scalpel cut while performing a necropsy on a dead
Blue
Jay (CDC Morbidity and Mortality Weekly Review, 20 December 2002)
It is best to assume that any specimen could be infectious and to take
proper
precautions at all times. Specifically:
- Neither refrigeration nor freezing will kill the
virus.
Ornithologists working with thawed tissue or specimens should
assume
that this material contains live virus.
- Ornithologists preparing specimens or working with
tissue
from fresh (never frozen) birds should be aware that the virus will
remain
viable in dead birds for several days.
- Ornithologists preparing specimens should take care
to
avoid scalpel cuts and punctures. If they occur, cleanse the area
promptly
and thoroughly, apply antiseptic and report the incident
to a supervisor. If signs of illness occur within two weeks of
exposure,
prompt medical evaluation and consultation with public health
authorities should be sought.
- Standard measures to minimize exposure to fluids or
tissues
during handling of potentially infected tissue comprise standard
droplet
and contact precautions. These include:
- barrier protections such as gloves, masks, and eyewear
- proper
use and disposal of needles, scalpels, and other sharp instruments
<>minimizing the generation of aerosols (such as
vigorous spraying of water on carcasses or work surfaces).
<>While wearing
gloves, be careful not to handle anything but the materials involved in
the procedure. Touching equipment,
phones, wastebaskets or other surfaces may cause contamination. Be
aware
of touching the face, hair, and clothing
as well. Researchers who use gloves must learn the proper way to remove
and
dispose of gloves and must avoid touching unprotected skin with the
gloved hand. Consult your safety officer or safety manual.
Typical instructions say to remove the first glove by grasping the cuff
–
being careful to avoid touching the
bare skin or the wrist of arm - and peeling the glove off the hand so
that
the glove is inside out. Repeat this process with the second hand,
touching
the inside of the glove cuff, rather than the
outside.
Wash hands immediately with soap and water.
- Although the isolate of WNV is classified as a
Biosafety Level 3 agent,
it is considered acceptable practice to work with specimens and tissue
in a Biosafety
Level 2 laboratory conditions. See Biosafety in Microbiological and
Biomedical
Laboratories 4th ed. [http://bmbl.od.nih.gov] for details.
In the field
Although there are no documented cases of ornithologists or bird
banders
contracting WNV from handling living or dead birds, it is also the case
that
there has been no surveillance of ornithologists or bird banders to
determine
the presence/absence or prevalence of the disease. Even if such
surveillance
were to be implemented, it would be difficult to know if the disease
had
been contracted through contact with bird feces or saliva or if it had
been
contracted from an insect bite – at the research site or elsewhere.
It has been confirmed that WNV may be shed from the cloacal and oral
cavities
(Komar et al. 2002). Therefore, contact with droppings,
dropping-contaminated
feathers, or the cloaca may result in exposure to WNV.
- Be sure to have antispectic (not antibacterial or
antimicrobial)
available for handwashing and first aid for cuts or punctures sustained
while
handling birds.
- Reasonable precautions include the use of
antiseptic
wipes. This will protect both the researcher and the birds subsequently
handled
by the researcher.
- Avoid contact with bird feces.
- If bitten by a bird, wash hands (when possible) or
use
antiseptic (not antibacterial or antimicrobial) wipes or even a small
amount
of fresh bleach.
- Since ornithologists often use needles to take
blood
samples, extra care should be taken to avoid needle sticks.
- Public health officials consider gloves to be an
appropriate
precaution but ornithologists rarely wear gloves when handling birds,
particularly
in the field. If gloves are worn, they should be changed
or decontaminated with 70% ethanol or other appropriate substance after
handling
each bird to avoid transmission from one bird to another. Again,
be familiar with proper glove removal and disposal.
Other barrier protections such as goggles and masks are standard
precautions
against inadvertent exposure to droplets and fluids.
- Ornithologists and bird banders should take the
same
reasonable precautions to minimize risks – of various diseases - posed
by
mosquito bites. Reasonable measures include protective clothing (long
sleeves, long pants, socks),
and the use of DEET or other insect repellants – with repeated
applications
over time. For detailed information about the proper use
of DEET and summary of a recent assessment of the efficacy and safety
of
DEET, see the appendix).
Precautions against transmission to birds and other wildlife
- Ornithologists and bird banders should not re-use
contaminated
bags, boxes or other holding/carrying devices and other devices used to
restrain
birds during processing.
The North American Banding Council manual states, “Launder bird bags
frequently,
as they must be kept clean,” and “If a diseased bird is caught, it is
extremely important to put that bag aside until it has been washed and
disinfected.”
However, as it is not possible to determine if a bird is shedding
virus,
the better practice would be to carry an ample supply
of bags or other holding/carrying devices so that no bag or other
holding
device is used more than once before laundering.
- When preparing specimens in the field, place waste
material
in a biosafety bag, seal it, and burn it, or carry it out with you.
- Never re-use needles or scalpel blades unless
decontaminated
with a fresh 10% bleach solution.
REFERENCES
Centers for Disease Control Morbidity and Mortality Weekly Review, 20
December
2002. [http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5150a2.htm].
Komar, Nicholas, Robert Lanciotti, Richard Bowen, Stanley Langevin, and
Michel
Bunning. 2002. Detection of West Nile Virus in Oral and Cloacal Swabs
Collected
from Bird Carcasses. Emerging Infectious Diseases 8: 741-742.
Nash D, Mostashari F, Fine A, Miller J, O'Leary D, Murray K, et al.
2001.
The outbreak of West Nile virus infection in the New York City area in
1999.
New England Journal of Medicine 344:1807- 1814.
This publication was reviewed by scientific experts under the
auspices
of the Ornithological Council. You may contact the Council for
further
information.
The Ornithological Council thanks the following individuals for sharing
their
time and expertise:
Nick Komar, ScD.
Arbovirus Diseases Branch
Centers for Disease Control and Prevention
Robert G. McLean, Ph.D.
Program Manager Wildlife Diseases,
National Wildlife Research Center (Wildlife Services, Animal and Plant
Health
Inspection Service,
U.S. Department of Agriculture)
Sarah A. Lister, DVM, MPH, Dipl. ACVPM
Director of Public Health Preparedness
Association of Public Health Laboratories
Brenda J. Nordenstam, Ph.D.
Associate Professor
College of Environmental Science and Forestry
State University of New York at Syracuse
Citation: Ornithological Council (2003). West Nile Virus: what
ornithologists
and bird banders should know.
The Ornithological Council (OC) was founded in 1992 as a non-profit
organization by the American Ornithologists' Union, Association of
Field Ornithologists,
Cooper Ornithological Society, Pacific Seabird Group, Raptor Research
Foundation,
Waterbird Society, and Wilson Ornithological Society. The Society
for
the Conservation and Study of Caribbean Birds, Seccíon
Mexicana
del Consejo Internacional para la Preservacíon de las Aves
(CIPAMEX),
the Society of Canadian Ornithologists/Société des
Ornithologistes
du Canada, and the Neotropical Ornithological Society have joined the
OC
in recent years.
The Ornithological Council represents ornithologists to the
government agencies that make rules and regulations and issue permits
that affect the practice of ornithology. The Council has been
particularly effective on these issues and new, major changes of
benefit to the ornithological community
are being implemented.
The Ornithological Council has been representing scientific
ornithology on a wide variety of public issues concerning the science
of ornithology, birds, and bird habitat. The Council gives
ornithologists a means to provide timely and relevant information from
ornithological science to legislators, managers, conservation
organizations, and private industry. The Council also keeps
ornithologists informed about policy issues affecting birds.
The member societies of the Ornithological Council provide
approximately one half of the Council's annual budget.
Contributions of individual ornithologists are needed if the Council is
to continue providing its excellent services.
How to contact the Ornithological Council:
Ellen Paul, Executive
Director
David E. Blockstein, Ph.D., Chairman of the Board
8722 Preston
Place
National Council for Science and the Environment
Chevy Chase, MD
20815
1707 H St., N.W., Suite 200
Phone: (301)
986-8568
Washington, D.C. 20006
Fax: (301)
986-5205
Phone: (202) 207-0004
e-mail: ellen.paul@verizon.net
Fax: (202) 628-4311
E-mail: oc@cnie.org
For information about the Ornithological Council, please visit our
website
at http://www.nmnh.si.edu/BIRDNET.
APPENDIX: THE PROPER USE OF DEET AND AN ASSESSMENT OF THE RISKS OF THE
USE
OF DEET
To determine the relative efficacy of DEET versus other insect
repellants,
Fraidin et al. tested the relative efficacy of seven botanical insect
repellents;
four products containing N,N-diethyl-m-toluamide, now called
N,N-diethyl-3-methylbenzamide
(DEET); a repellent containing IR3535 (ethyl
butylacetylaminopropionate);
three repellent-impregnated wristbands; and a moisturizer that is
commonly
claimed to have repellent effects. These products were tested in a
controlled
laboratory environment in which the species of the mosquitoes, their
age,
their degree of hunger, the humidity, the temperature, and the
light–dark
cycle were all kept constant.
They found that DEET-based products provided complete protection for
the
longest duration. Higher concentrations of DEET provided longer-lasting
protection.
A formulation containing 23.8 percent DEET had a mean
complete-protection
time of 301.5 minutes. A soybean-oil–based repellent protected against
mosquito
bites for an average of 94.6 minutes. The IR3535-based repellent
protected
for an average of 22.9 minutes. All other botanical repellents they
tested
provided protection for a mean duration of less than 20 minutes.
Repellent-impregnated
wristbands offered no protection.
They concluded that currently available non-DEET repellents do not
provide
protection for durations similar to those of DEET-based repellents and
cannot
be relied on to provide prolonged protection in environments where
mosquito-borne
diseases are a substantial threat.
Depending on the time in the field, the temperature, exposure to water,
perspiration,
or concentration of DEET in the product, you may need to re-apply. This
study
found that a product containing 23.8% DEET provided an average of 5
hours
of protection against mosquito bites. A product containing 20% DEET
provided
almost 4 hours of protection, and a product with 6.65% DEET provided
almost
2 hours of protection. DEET may be washed off by perspiration or rain,
and
its efficacy decreases dramatically with rising outdoor temperatures.
Much has been said about the safety of DEET usage. The Fraidin paper
addressed
this issue:
Despite the substantial attention paid by the lay
press every
year to the safety of DEET, this repellent has been subjected to more
scientific
and toxicologic scrutiny than any other repellent substance. The
extensive
accumulated toxicologic data on DEET have been reviewed elsewhere. DEET
has
a remarkable safety profile after 40 years of use and nearly 8 billion
human
applications. Fewer than 50 cases of serious toxic effects have been
documented
in the medical literature since 1960, and three quarters of them
resolved
without sequelae. Many of these cases of toxic effects involved
long-term,
heavy, frequent, or whole-body application of DEET. No correlation has
been
found between the concentration of DEET used and the risk of toxic
effects.
As part of the Reregistration Eligibility Decision on DEET, released in
1998,
the Environmental Protection Agency reviewed the accumulated data on
the
toxicity of DEET and concluded that "normal use of DEET does not
present
a health concern to the general U.S. population." When applied with
common
sense, DEET-based repellents can be expected to provide a safe as well
as
a long-lasting repellent effect. Until a better repellent becomes
available,
DEET-based repellents remain the gold standard of protection under
circumstances
in which it is crucial to be protected against arthropod bites that
might
transmit disease.
Fradin, M.D., Mark S. and John F. Day, Ph.D. 2002. Comparative Efficacy
of
Insect Repellents Against Mosquito Bites. New England Journal of
Medicine
347: 13-18; available online at
<http://content.nejm.org/cgi/content/full/347/1/13>.
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