SCRUB TYPHUS - SCIENCE AND TECHNOLOGY
News: Scrub
typhus: combination therapy can save more lives
What's in the news?
● Scrub typhus, a life-threatening
infection caused by Orientia tsutsugamushi bacteria, is a major public health threat in South and Southeast Asia.
● As
per estimates, nearly one million cases are reported from South and Southeast
Asia with 10% mortality.
● India
is one of the hotspots with at least 25% of the disease burden - in CMC Vellore
alone, 500- 1,000 patients are treated each year, of which 250-300 have severe
disease.
Key takeaways:
● Scrub typhus
is a major public health threat having a very high mortality rate in patients
with severe disease despite diagnosis and treatment.
● Till
date, monotherapies using either doxycycline
or azithromycin was the commonly used treatment.
● The
frequencies of respiratory, renal, hepatic, and central nervous system
complications were lower in the combination-therapy group than in either of the
monotherapy groups.
Transmission:
● The
disease is more common during the wet season when the mites lay eggs.
Incubation period (time between bite and beginning of symptoms) is 10–14 days.
● It
is usually transmitted by mites that
are found in the shrubs in hilly areas. It can also be transmitted by lice,
ticks and fleas.
Causes of Scrub Typhus:
● The
species which transmit Scrub typhus are found in areas which have heavy scrub
vegetation.
Symptoms:
● The
symptoms of scrub typhus are similar to chikungunya. At onset there is fever, headache, bodyache, cough and
gastrointestinal symptoms.
● Patients
with a mild infection may recover without any other symptoms.
● However,
roughly every second patient develops a visible black scab at the point of the
bite, with a swelling of the lymph nodes.
● In
about a third of cases, a delayed onset of rashes occurs 4-6 days into the
disease. Severe cases typically include encephalitis and interstitial pneumonia
due to vascular injury. The fatality
rate is 7%.
● Other
symptoms include high fever, skin rashes, respiratory problems, red eyes and
unconsciousness. Some of the patients also develop joint pains, which is
characteristic of chikungunya.
● It
may progress on to respiratory distress, pneumonitis (inflammation of lung
tissue), and multi-organ failure.
Treatment:
● If
detected in time, the disease can be cured using antibiotics.
● Antibiotics like
Doxycycline or Azithromycin are commonly used to
treat the disease.
● Dengue
and chikungunya are self-limiting viral diseases that do not have any
treatment, apart from management of symptoms.
● In
scrub typhus, however, administering antibiotics on time can save lives.
Preventive measures:
● Limit
the spread of rodents.
● Pets
should be cleaned regularly.
● Skin
should be properly covered while visiting a jungle or area with a lot of
shrubs.