Transcript Slide 1
What is an emerging disease ?
An emerging disease is the one which
has evoked suddenly among the
population for the first time or that
may have existed previously but is
rapidly increasing in incidence or
geographic range.
These infectious diseases are continuing
danger to everyone. e.g. SARS, West
Nile virus, Lyme disease, AIDS, etc.
What is multiple drug resistance ?
Multiple drug resistance or multidrug
resistance is resistance to many
structurally unrelated chemotherapy
agents in cells that have developed
natural resistance to a single cytotoxic
compound. It is the property of a disease
causing micro organism to withstand the
drug therapy. This situation is more likely
if the drug is not taken properly, or not
prescribed properly.
What is Lyme disease ?
Lyme disease or Lyme borreliosis is
an emerging infectious disease
caused by at least three species of
bacteria belonging to the genus
Borrelia.
Lyme disease is the most common
tick-borne disease in the northern
hemisphere. Borrelia is transmitted to
humans by the bite of infected ticks
belonging to a few species of the
genus Ixodes ("hard ticks").
History of Lyme disease :
This Lyme disease is named after the
village, Lyme of Connecticut in USA,
where a number of cases were
identified in the year 1975.
In 1978 Allen Steere realized that
the Lyme disease is a tick- borne
disease, but still the cause of the
disease was unknown until 1982,
when borrelia burgdorferi was
identified by Willy Burgdorfer.
Location
Borrelia
burgdorferi sensu
lato is the main
cause of Lyme
disease in the
United States,
whereas borrelia
afzelii and Borrelia
garinii cause most
European cases.
Stages in Lyme disease
THERE ARE THREE STAGES IN LYME
DISEASE :
Early localized infection
Early disseminated infection
Late persistent infection
Stage 1 : Early localized infection
The classical sign of
an early local
infection in the case
of Lyme is a circular,
red colored rash
known as erythema
chronicum migrans
(also erythema
migrans or EM),
which occurs at the
site of the tick bite, in
about 3 to 30 days
after the tick bite.
Stage 2 : Early disseminated infection
After the onset of local infection, the
borrelia bacteria may begin to spread
through the bloodstream. Erythema
chronicum migrans may develop at
sites across the body that bears no
relation to the original tick bite.
Other symptoms include migrating
pain in muscles, joint, and tendons,
and heart palpitations and
dizziness caused by changes in
heartbeat.
Stage 3 : late persistent infection
If this Lyme disease if left untreated for
several months the patient may face
serious conditions and chronic
symptoms that may affect many parts of
the body including brain, nerves, eyes,
joints and heart.
Chronic neurologic symptoms occur in up
to 5% of untreated patients. A
polyneuropathy that involves severe
pains, numbness and tingling in the
hands or feet may also occur.
Causative agents
Lyme disease is caused by Gramnegative spirochetal bacteria from the
genus Borrelia.
The group Borrelia burgdorferi
sensu lato is made up of three closelyrelated species that are probably
responsible for the large majority of
cases: B. burgdorferi sensu stricto
(predominant in North America, but
also present in Europe), B. afzelii, and
B. garinii (both predominant in
Eurasia).
Images of bacteria borrelia
Transmission
The Lyme disease bacterium, Borrelia
burgdorferi, is transmitted among
animals – and to humans – through
the bites of certain species of ticks.
Blacklegged (or deer) ticks can
transmit several tick-borne diseases
including anaplasmosis, babesiosis
and Lyme disease.
Images of the tick bite
Ticks
Ticks have evolved to become one of the
most important groups of arthropod
vectors of human pathogens.
Ticks attach to skin of the host by using
their hypostome as an anchor and create
a feeding lesion to ingest blood or tissue
fluids. Disease-causing organisms may be
ingested or expelled during feeding.
Symptoms and signs
Lyme disease affects different areas of
the body. The site that the tick bites the
body is where the bacteria enter
through the skin.
The infection causes an expanding
reddish rash that is often associated
with "flu-like" symptoms. Later, it can
produce abnormalities in the joints,
heart, and nervous system.
Laboratory testing
The first step uses an ELISA or IFA
test. If the ELISA or IFA is
negative, it is highly unlikely that
the person has Lyme disease, and
no further testing is
recommended. If the ELISA or IFA
is positive or indeterminate a
second step should be performed
to confirm the results.
The second step is a Western blot
test. This test is designed to be
"specific," meaning that it will
usually be positive only if a person
has been truly infected. If the
Western blot is negative, it
suggests that the first test was a
false positive, which can occur for
several reasons.
Diagnosis
In early Lyme disease, doctors make
diagnosis simply by finding the classic
red rash in people who have recently
been in regions in which Lyme disease
is common.
The doctor might review the patient's
history and examine the patient in order
to exclude diseases with similar findings
in the joints, heart, and nervous
system.
Vaccination
INTRAMUSCULAR
is a vaccine used to
provide protection
against Lyme disease.
This vaccine is not a
treatment for Lyme
disease. Researches are
going on about the
vaccines for Lyme
disease.
Medical treatment
Mostly Lyme disease is curable with
antibiotics. The type of antibiotic depends
on the stage of the disease and the areas of
the body are affected.
Early illness is usually treated with
medicines taken by mouth, for example,
doxycycline, amoxicillin, or cefuroxime
axetil.
Later illness such as nervous-system
disease might require intravenous drugs;
examples are ceftriaxone (Rocephin) and
penicillin G.
Drugs Which Are Resistant to Borrelia
Erythromycin
Gentamicin
Cefuroxime
Doxycycline
Amoxicillin
Streptomycin
Prevention
Avoid areas with lot ticks.
Ticks can also be removed with
tweezers.
Check your skin and clothes with
areas of ticks.
Wearing long clothing can prevent the
skin from bite of ticks.
Conclusion
Thus the Lyme, which is an emerging
infectious disease, can be treated by using antibiotics
or alternative therapies in the earlier stages. But
when it is left untreated for longer days or if the
antibiotics are not properly given it would become
multiple drugs resistant.
Ticks that transmit B. burgdorferi to humans can
also carry and transmit several other parasites such
as Theileria microti and anaplasma
phagocytophilum, which cause the diseases
babesiosis and human granulocytic
anaplasmosis, respectively. Hence awareness about
these diseases should also be created.