Why should I
learn about bats and rabies?
Public health
importance of rabies:
Over the last 100
years, rabies in the United States has changed dramatically.
More than 90% of all animal cases reported annually to CDC
now occur in wildlife; before 1960 the majority were in
domestic animals. The principal rabies hosts today are wild
carnivores and bats. The number of rabies-related human
deaths in the United States has declined from more than 100
annually at the turn of the century to one or two per year
in the 1990's. Modern day prophylaxis has proven nearly 100%
successful. In the United States, human fatalities
associated with rabies occur in people who fail to seek
medical assistance, usually because they were unaware of
their exposure.
HANTAVIRUS
PULMONARY SYNDROME
I've been hearing about
Hantavirus Pulmonary Syndrome (HPS) in the news recently?
What is it?
HPS is a serious respiratory
disease carried by certain wild rodents, mainly deer mice,
and is passed to humans through contact with a rodent's
infected urine, droppings or saliva. Breathing in
contaminated mist or dust is the most common form of
transmission.
How serious is
it?
HPS is extremely serious and can be
fatal; the case fatality rate is high. As of June 19, 1998,
there have been 185 cases recognized nationwide with a case
fatality of 44 percent.
Is there more risk of HPS this
year due to the wet weather?
This year
there have been increased populations of some rodent hosts
of hantaviruses in some areas because of increased
vegetation resulting from wetter than usual weather. This
increase is unlikely to be statewide, but in order to
prevent HPS, precaution is recommended. As always, if you
notice increased numbers of wild mice in rural areas, steps
should be taken to minimize human contact with these
rodents.
Who can get
HPS?
Since the virus is carried by deer
mice and other wild rodents, persons who are exposed to
infected rodents or rodent-infested areas are at risk of
contracting HPS. This would include persons living or
working in rural or semi-rural areas. Deer mice and other
rodents that carry HPS are generally not found in urban or
suburban settings.
How can one get
HPS?
The infected rodents excrete the virus
in their urine, droppings, and saliva. These droppings
contaminate dirt and dust that becomes airborne. People are
infected by inhaling airborne particles of the virus or by
direct contact with rodents, their droppings, or
nests.
What is the incubation
period?
The incubation period varies
widely, but ranges from 1 to 6 weeks, with an average of 2-3
weeks.
What are the
symptoms?
The early symptoms include fever,
headache, and muscle pain, severe abdominal, joint and lower
back pain, nausea and vomiting. A cough and shortness of
breath usually develops 1 to 5 days after the onset of
symptoms. The primary symptom of HPS is difficulty in
breathing due to fluid build-up in the lungs. This can
quickly progress to respiratory failure.
How is HPS
treated?
Currently there is no effective
drug treatment for HPS. When HPS infection is suspected or
confirmed, early admission to a hospital where careful
monitoring, treatment of symptoms, and good supportive
therapy can be provided is important. If you have had
exposure to rodents and experience symptoms mentioned above,
it would be helpful to mention the exposure to your
physician. A quick diagnosis helps the physician take the
appropriate measures in managing the patient.
How can HPS be
prevented?
Avoid rodent contact by taking
the following measures:
- Always limit food sources that will
attract rodents both inside and outside the home. Keep pet
food and livestock feed in rodent-proof containers. Clean
up spills from bird feeders.
- Limit possible nesting sites in or near
the home. Keep grass and vegetation near homes trimmed
short. Store firewood above ground and away from the
house. Remove wood and junk piles, abandoned vehicles,
equipment and other sources of shelter from the
property.
- Prevent rodent entrance into the home.
Seal all holes or cracks 1/4 inch or larger with steel
wool, caulking, metal screening or flashing. Insure
weather seals under doors are in good repair and fit
tightly when the door is closed.
- If rodents are present in the home,
eliminate them by using Asnap-traps baited with a peanut
butter/oatmeal mix. Trapping success will be increased if
food sources have been eliminated and entrances to the
building sealed to keep new mice from moving in. Continue
trapping efforts as long as rodent presence is suspected
in the home.
- Use a solution of household bleach (one
cup bleach per gallon of water) to disinfect rodents'
carcasses before handling. Spray the rodent and trap and
allow to sit for 5-10 minutes Wear rubber gloves when
handling trapped rodents. Disinfect the gloves and the
trap afterward.
- Air out rodent infested buildings or
areas at least 30 minutes before cleaning. Do not sweep or
dry vacuum rodent contaminated surfaces, which may stir up
the dust and allow potentially contaminated dust to be
breathed in. Spray contaminated materials with the bleach
solution and allow it to soak in 5-10 minutes before
cleaning them with a mop, sponge or wet (shop) vacuum.
Wear gloves.
- In heavily rodent infested areas or
situations where ventilation and/or wet clean-up cannot be
effectively done, use a face mask with a high efficiency
particulate air (HEPA) filter.
- When camping or sleeping outdoors, avoid
disturbing or sleeping near rodent droppings and/or
burrows. Sleep in tents with floors, above ground or on a
ground cloth, not directly on the ground.
HISTOPLASMOSIS
What is histoplasmosis and what
causes it?
Histoplasmosis is an infectious
disease of the lungs caused by a fungus called Histoplasma
capsulatum. The infection sometimes can spread to other
parts of the body.
This Histoplasma organism thrives in
moderate temperatures and moist environments. Droppings from
chickens, pigeons, starlings, blackbirds, and bats support
its growth. Birds are not infected with it because of their
high body temperatures, but they do carry it on their
feathers. Bats can be infected because they have a lower
body temperature than birds and can excrete the organism in
their droppings.
To multiply, Histoplasma capsulatum produces
small spores called conidia. The conidia of Histoplasma
capsulatum are only two millionths of a meter (microns, µm)
in diameter. When these conidia are inhaled, they are small
enough that they enter the lungs and start an infection.
Many of these infections are easily overlooked because they
either produce mild symptoms or none at all. However,
histoplasmosis can be severe and produce an illness similar
to tuberculosis.
How can we prevent
histoplasmosis?
Prevention of
histoplasmosis relies on avoiding exposure to dust in a
contaminated environment. Before anyone cleans chicken coops
or other contaminated soil, spraying with water is advisable
to reduce dust. Decontamination with 3% formaldehyde has
been shown to be effective.
However, formaldehyde solutions should be
used with caution since this chemical may cause adverse
health effects following inhalation, ingestion, or skin or
eye contact.
Persons working in contaminated areas should
use protective clothing such as gloves and coveralls. They
should also use a respirator equipped with a high efficiency
particulate air (HEPA) filter that is capable of filtering
particles down to two microns in size. Such respirators are
suitable as long as the occupational exposure limit for
formaldehyde is not exceeded. For major clean up operations
of prolonged exposure, a powered air purifying or supplied
air respirator may be
necessary.
