Ticks
on Medvednica and risks from contagious diseases
Borislav Aleraj, dr. med.,
specialist epidemiologist
Epidemiology service at Croatian institution for public health  http://www.hzjz.hr
Rockefellerova 7, 10000 Zagreb
Tel: 01/4683 004 or 01/4683 005.
In nature ticks are very widely spread.
They can be found in plain and mountain forests such as Medvednica,
but also in fields, gardens, hedges, and house lots.
Each year in spring and early summer
they appear in larger numbers. They are most active in May and
June. You can run into them still in fall, but that's rare, and
exceptionally during winter if it is warm and without snow. Their
number varies from year to year for many different factors of
which some are know to us and many still unknown. For example,
mild winter is favorable for their large number.
TICKS AND CONTAGIOUS DISEASES
Through their bite ticks can transfer
some diseases on humans. Luckily, not all ticks are infected
by microorganisms that can harm men, but just a small portion
of them and neither are they dispersed on all locations.
The ticks we are talking about are forest
ticks species Ixodes ricinus. They can transmit the
following two diseases on human: tick -borne encephalitis and
an infection caused by bacteria Borrelia burgdorferi, known
under the name Lyme-disease (or Lyme boreliosis).
Distribution of the virus – infectious
agent of tick -borne encephalitis in Croatia is well known .
It is a known fact that in the urban zone of Zagreb all the way
to the foothills of Medvednica the danger of tick -borne encephalitis
does not exist, although there are ticks. On the other hand,
Medvednica represents a zone where it exists. But this is a natural
focal point of a rather low intensity and the risk of disease
is very small. This can be show by only a few infected persons
(range from 0 to 5) annually.
About distribution of Lyme boreliosis
there is less data, since this recently clarified disease has
been systematically analyzed for only about 10 years. But, according
to the available data it seems its distribution is much wider
than the one for tick -borne encephalitis (the possibility of
occurrence of disease after the bite is much larger), and the
possibility of catching the disease exists on Medvednica as well
as in the plains. And again, luckily, the possibility is still
rather small, with about a hundred infected people annually (statistics
for the city of Zagreb).
WHERE CAN YOU FIND TICKS IN NATURE?
For hikers it is important to know that
at the time of their intensive activity, which is spring and
early summer, ticks are located on shrubs and ground vegetation
up to one meter high. There, on the tips of branches they stand,
with their tiny legs extended, waiting for a warm-blooded being
(animals, humans) to pass by them, so that they can attach themselves
on it, find an appropriate place on the body, sting the skin
with their sharp proboscis and suck blood.
Blood meal is necessary for ticks in
every stage of their life, and a grown-up female needs the largest
amount to produce several hundreds, even thousands of eggs. During
the sucking, if they are infected with for some people dangerous
microbe, ticks can transmit that infection. That chance is higher
if the time of sucking and the stay of the tick on the body is
longer, while the largest risk is if the tick is an adult female.
In a couple of days she can multiple her size a couple of times,
as large as a pea, and in color and appearance remind of Castor
bean fruit ( Ricinus communis ) (that is why it is called Ixodes
ricinus) Female Ixodes ricinus can be recognized
by a red half-moon abdomen, unlike plain darker or lighter brown
males or larvae.
The easiest way for a tick to attach
itself is if people walk through shrubs, for example during forest
works, picking mushrooms, forest fruits, etc., and if they are
wearing clothes made of lint material (wool, flannel) on which
ticks can easily hold on.
HOW TO PROTECT ONESELF FROM TICK BITE
AND POSSIBLE DISEASES WHICH CAN BE TRANSMITTED TO HUMANS?
At the time of their greatest activity, during
every stay in the nature one should consider that possibility
as well, and after returning home from Medvednica, immediately
check the whole body, especially places where the skin is the
softest (in children especially hair root area), and if
the tick has attached itself, immediately remove it. In this
way the possibility of getting a disease is almost completely
avoided, since it takes ticks several hours to transmit a disease
(adequate infective dosage), from the moment of attaching to
the body.
REMOVING TICKS FROM BODY
Recently it is considered that it is
best not to put anything on the tick (such as oil, nail polish,
etc.) because unpleasant stimulation can induce convulsions,
and a larger amount of possibly contagious material can enter
sting wound. However, if you decide to do it, it is best to daze
the tick with alcohol (cover with absorbent cotton soaked in
alcohol and keep for 3-5 min) and than attempt to remove
it using tweezers (a good one is cosmetics tweezers with straight
edges) disinfected in alcohol or burned with flame. Tick should
be grasped as close to the head as possible as to avoid crushing
abdomen, and with careful and calm puling in all directions take
it out. Special instruments resembling tweezers or shaped as
a little plate with a slit for removing ticks have been made,
which can also fit the purpose quite well.
One should not give up on removing tick
if it does not go easily, and for instance wait until tomorrow
to seek medical intervention, but by all means at least take
of the body (abdomen), since the remaining proboscis in the skin
can not cause a disease. Later on we can then take out the proboscis
ourselves or go to a doctor to do it.
ADVICE
At the height of tick season (May -
July), keep in mind the possibility of such “encounter” during
each stay in the nature, even on Medvednica. During the stay
one should choose wider trails and avoid crawling through brushwood,
and try to wear clothes made of smooth materials. Clothes should
not be left to rest in shrubs.
Mosquito repellents partially put off
ticks, to, and they can be applied on those parts of the skin
where clothes end (wrists, ankles, neck) or sprayed on clothes
if they are in the form of spray.
After returning home, but also during
the trip in the nature, you should immediately check yourself
and others (for example children), and if you find a tick remove
it right away. In this way you have removed the greatest part
of the risk caused by tick bite.
WHAT TO DO IF A TICK HAS BEEN ON THE
BODY FOR A LONGER TIME AND HAS ABSORBED BLOOD?
If the tick remained on the body for
a longer time, for example over night, it could have, if it was
infected, transmit the disease to person. In the first couple
of days it is possible to protect oneself from tick -borne encephalitis
through so called passive immune protection (hyperimune gamaglobuline).
Advice and answer on the possibility and need for such protection
can be found at Epidemiology service at Croatian institution
for public health.
If after a tick bite one gets tick-borne
encephalitis with high fever, headache, nausea, neck stiffening
and signs of central nervous system damage, which is luckily
very rare and can develop from 4 to 30 days after the bite, it
is necessary to go to a hospital. In Zagreb this is Clinic for
infective diseases. Lyme-disease, which most commonly starts
with noticeable redness of the skin around the place of the bite,
is in the beginning stage of the illness successfully treated
with antibiotics without the need for hospitalization.
PREVENTIVE IMMUNOLOGY PROTECTION
Those Medvednica lovers that often visit
it and especially the ones that are more exposed to tick bites
by walking through brushwood or close to shrubs, can get preventive
vaccination for tick-borne encephalitis. One should get 2 vaccinations
3-4 weeks apart (after which complete protection is achieved),
and get additional vaccination after one year for maintaining
protection, and after that in longer periods, every 3-5 years.
There is no vaccination for Lyme-disease,
but on the bright side, at the moment when one notices redness
of the skin it can be successfully treated with antibiotics.
It is recommended to control the bite zone for about a month
in case of red skin change, and seek medical help.
LAST BUT NOT LEAST
Last but not least it should be pointed
out that existence of these health risks on Medvednica, and such
and even much larger exist in many other forest mountains in
Europe , should not be the reason for avoiding trips to the nature.
And a bit of care and attention, with immune protection if needed,
will contribute to completely safe trips.
|
hrvatski
