Scrub typhus, also known as bush typhus, is a disease caused by a bacteria called ORIENTIA TSUTSUGAMUSHI. Scrub typhus is spread to people through bites of infected chiggers (larval mites). Most cases of scrub typhus occur in rural areas of Southeast Asia, Indonesia, China, Japan, India, and northern Australia. Anyone living in or travelling to areas where scrub typhus is found could get infected Scrub typhus is not transmitted directly from person to person; it is only transmitted by the bites of vectors Chiggers are abundant in locales with high relative humidity (60%–85%), low temperature (20°C–30°C), low incidence of sunlight, and a dense substrate-vegetative canopy. Occupational risk is higher in farmers (aged 50–69 years), females.

1. SCRUB TYPHUS
Pankaj Singh Rana
Nurse Practitioner in
Critical Care

2. INTRODUCTION
• Scrub typhus, also known as bush typhus, is a
disease caused by a bacteria called ORIENTIA
TSUTSUGAMUSHI.
• Scrub typhus is spread to people through bites of
infected chiggers (larval mites).
• Most cases of scrub typhus occur in rural areas
of Southeast Asia, Indonesia, China, Japan,
India, and northern Australia. Anyone living in or
travelling to areas where scrub typhus is found
could get infected
As per CDC

3. • Scrub typhus is not transmitted directly from
person to person; it is only transmitted by the
bites of vectors
• Chiggers are abundant in locales with high
relative humidity (60%–85%), low temperature
(20°C–30°C), low incidence of sunlight, and a
dense substrate-vegetative canopy.
• Occupational risk is higher in farmers (aged 50–
69 years), females.

4. TRANSMISION

5. SIGN AND SYMPTOMS
• Fever and chills
• Headache
• Body aches and muscle pain
• A dark, scab-like region at the site of the
chigger bite (also known as eschar)
• Mental changes, ranging from confusion to
coma
• Enlarged lymph nodes
• Rash

6. More virulent strains of O. tsutsugamushi can
cause hemorrhaging and intravascular coagulation. Morbilliform
rash, splenomegaly are typical signs.
Leukopenia and abnormal liver function tests are commonly
seen in the early phase of the illness.
Pneumonitis, encephalitis, and myocarditis occur in the late
phase of illness. It has particularly been shown to be the most
common cause of acute encephalitis syndrome in Bihar, India

7. DIGNOSTIC EVALUATION
eschar incidence varies from 7% to 97% in endemic
areas and is painless. Eschars are often found in covered
areas of the body, such as the groin, axilla, chest, and
lower back, including the buttocks

8. DIGNOSTIC EVALUATION
• The gold standard is indirect
immunofluorescence
• Culture and polymerase chain reaction
• The cheapest and most easily available
serological test is the Weil-Felix test. (non
reliable)
• ELISA (enzyme-linked immunosorbent assay)

9. • Routine laboratory studies in patients with scrub
typhus reveal early lymphopenia with late
lymphocytosis. A decrease in the CD4:CD8
lymphocyte ratio may also be noted.
• Thrombocytopenia is also seen.]The
hematologic manifestations may raise the
suspicion of dengue infection.
• Elevated transaminase levels may be present in
75-95% of patients.
• Hypoalbuminemia occurs in about 50% of
cases, whereas hyperbilirubinemia is rare.

10. • This illness is thus clinically indistinguishable
from malaria, dengue fever, other rickettsioses,
leptospirosis, and enteric fever, which are
common causes of acute undifferentiated fever
as seen in scrub typhus.

11. TREATMENT

12. As per DHR-ICMR guidelines for diagnosis and
management of rickettsial diseases in India (2015),
the scrub typhus can be managed at different levels
of health care facility as –
When rickettsial disease is suspected, without
waiting for laboratory confirmation, antibiotics should
be started. Without treatment, the disease is often
fatal. Since the use of antibiotics, case fatalities have
decreased from 4–40% to less than 2%.
1. At primary level health care facility:
The health care providers should:
a) Recognize disease severity:
In the patients with complications, Doxycycline
should be started before referral.

13. b) Refer to secondary or tertiary level health
care facility in patients with complications like
ARDS, meningo-encephalitis, acute renal
failure and multi-organ dysfunction. Along with
recommended management of community
acquired pneumonia, start Doxycycline when
the scrub typhus is considered likely.
c) In case of fever for 5 days or more where
dengue, malaria and typhoid have been ruled
out; following drugs should be administered
when scrub typhus is considered likely –

14. For Adults:
a) Doxycycline -200 mg/day in two divided doses
×7 days ( for patients ˃45 kg ).
Advise the patients to swallow capsules with
plenty of fluid during meals while sitting or
standing
OR
b) Azithromycin-500 mg in a single oral dose × 5
days.

15. • For Children:
a) Doxycycline -4.5 mg/kg of body weight/day in
two divided doses (for children < 45 kg) Or
b) Azithromycin-10mg/kg body weight in a single
dose × 5 days.
For Pregnant women:
Azithromycin can be administered to pregnant
women, as doxycycline is contraindicated.
Azithromycin- 500 mg in a single dose × 5 days.

16. 2. at secondary and tertiary level health care
facility:
a) Uncomplicated cases:
Start the treatment as specified in above cases.
b) In complicated cases: start the treatment
as following-
i) Intravenous Doxycycline:
• 100mg twice daily in 100 ml of Normal Saline to
be infused over ½ an hour initially followed by
oral therapy × 7-15 days.
OR

17. ii) Intravenous Azithromycin:
500mg IV in 250 ml Normal Saline to be infused
over 1 hour O.D. × 1-2 days followed by oral therapy
× 5 days.
OR
iii) Intravenous Chloramphenicol:
50-100 mg/kg/day 6 hourly to be infused over 1 hour
initially followed by oral therapy × 7-15 days.
iv) Management of complications should be done as
per institutional protocols. Doxycycline and/or
Chloramphenicol resistant strains are sensitive to
Azithromycin.

18. • Prophylactic Treatment:
Prophylaxis is recommended under special
circumstances in certain areas where the
disease is endemic. For prophylaxis, a single
oral dose of Chloramphenicol or tetracycline is
given once in every 5 days for a total of 35
days, with 5-day non-treatment intervals. It
produces active immunity to scrub typhus.

19. CONCLUSION
• Scrub typhus is an important cause of febrile
illness in the Asia-Pacific region. The main
management challenge is institution of specific
therapy in a timely and an effective manner.
• For this, rapid and accurate diagnosis becomes
necessary, especially in the absence of eschars.
• In resource-poor endemic settings, clinical
prediction rules have been defined and found
useful
• Finally, appropriate treatment should be initiated,
keeping in mind the risk and benefits afforded by
such treatment.