Scrub typhus is caused by the bacteria Orientia tsutsugamushi, which is transmitted through bites from trombiculid mite larvae. It causes symptoms like fever, headache, rash and organ dysfunction. Diagnosis is usually made clinically in endemic areas, but can be confirmed through serology tests. Without treatment with doxycycline or chloramphenicol, it can be fatal, but mortality has decreased to under 2% with antibiotics.

1. Scrub Typhus
.

2. • It ia caused by the intracellular parasite Orientia tsutsugamushi

3. Sign and symptoms
• Fever
• Headache
• Muscle pain
• Cough
• And gastrointestinal symptoms
Most virulent strains of O.tsutsugamushi can cause hemorrhaging and
intravascular coagulatoin

4. • Morbilliform rash ,eschar ,splenomegalyand lymphadenopathy are
typical sign
• Leukopenia and abnormal LFT are commonly seen in early phase of
illness
• Pneumonitis ,encephalitis and myocarditis occur in the late phage of
illness.

5. Causes
• Transmitted by some species of trombiculid mites(chiggers)which are
in the area of heavy scrub vegetation.
• The bite of the mite leaves a characteristic black echar that is useful
to the doctor for making the diagnosis

6. Diagnosis
• In endemic areas ,diagnosis is generally made on clinical grounds
alone.
• However overshadowing of the diagnosis is quite often as the clinical
symptoms overlaps with other infectious disease such as dengue
fever ,parathyroid and pyrexia of unknown origin(PUO).
• If the eschar can be identified it is quite diagnostic of scrub typhus
but it is very unreliable in the native population who have dark skin
• Unless is is actively searched for the eschar most likely would be
missed.

7. • Istory of mites bite is often absent since the bite doesnot inflict pain
and mites are almost too small to be seen by naked eye.
• Usually scrub typhus is often labelled as PUO in remote endemic
areas
• Blood culture is often negative
• Where doubt exists , the diagnosis may be confirmed by a laboratory
test such as serology that is often unavailable in most endemic areas,
since the serological test involved is not included in the routine
screening test for PUO

8. .
• The choice of lab. Test is not straightforward and all currently
available test have their limitation
• The cheapest and most easily available serological test is the Weil-
Felix test but this is notoriously unreliable.
• The gold standard is indirect immunofluorescence but the main
drawbacks of this method is the availability of florescence
microscopes which are not often available in resource –poor setting
where scrub typhus is endemic

9. .
• Indirect immunoperoxidase ,a modification of standard IFA method
,can be used with light microscope
• Rapid bedside kit have been described that produce a result within
one hour but the availability of these tests is severely limited by their
cost
• If the patient is from a non endemic area , then diagnosis can be
made from a single acute serum sample
• In patients from endemic areas, this is not possible because
antibodies may be found in upto 18 percent of healthy individuals
• Others methods—culture and PCR

10. Treatment
• Without treatment , the disease is often fatal
• Since the use of antibiotics ,case fatalities have decreased from 4-40
percent to less than 2 percent
• The drug most commonly used is doxycycline but chloramphenicol is
an alternative
• Strains that are resistant to doxycycline and chloramphenicol , for
these rifampicin and azithromycin are alterntives
• Azithromycin is doc in children and pregnant women of scrub typhus
and doxycycline resistance is suspected

11. • Azithromycin for less than 8 years;- 10mg/kg single oral dose
• For more than 8 years :- doxycycline 2.2mg/kg orally twice daily for 3 days
after resolution of fever(usually 5-10 days course)
• Adult treatment: azithromycin 500mg orally single dose Or doxycycline 100
mg orally twice daily for 5-10 days
• Pregnant women : azithromycin 500mg SOD
• Alternatives ;
ciprofloxacin 10mg/kg twice daily for 5-10 days
chloramphenicol25mg/kg/dose 6hrly for 5-10 days
Supportive treatment for management of complications