Orientia tsutsugamushi is an intracellular gram-negative organism that causes scrub typhus, one of the most common febrile illnesses in Asia. It is transmitted to humans through the bites of larval trombiculid mites. The mites become infected by biting infected rodents and can then transmit the bacteria to humans during feeding. Symptoms include acute fever, headache, rash and the formation of an eschar at the site of the bite. Complications can include acute respiratory distress syndrome, myocarditis and acute renal failure. Diagnosis is made by detecting a four-fold increase in antibody titers or a positive Weil-Felix test with the OXK strain. Treatment involves antibiotics

2. HISTORY
 Most wide spread A/C febrile illness caused by
orienta tsutsugamushi
 First identified in china in 313 AD
 Intacellular gram neg.org.isolated in japan in
1930
 Zoonoses in nature exists in nature between
mites and rodents

3. Geographical
distribution

4. Mode of transmission
 Mite  Rat,Mice  Mite  Rat,Mice
Man
 Maintained in nature transovarially in mites
 Adult and nymph mites are free living
 Larva (chiggar) feed on man introducing
bacteria

6. Adult
Larva
(chigger)

8. Clinical features
 Incubation period 6to20 days
 A/C fever and chills 104-105*c
 Head ache, Malaise, Prostration,
 Macular rashes -5th day
 ESCHAR-punched out ulcer with central
necrosis
 Lymph adenitis
 Hepato splenomegally

9. Eschar

10. Complications
 ARDS
 Myocarditis
 A/C Renal failure
 DIC

11. Diagnosis and treatment
 4 fold increase in antibody titre
 Weil felix positive withOXK STRAIN
 Immuno peroxidase test
 Immuno flurocent test
Responds to tetracycline,doxycycline,azithromyci etc.

12. PREVENTIVE MEASURES
 Avoid areas where there is known typhus
outbreak
 Avoid over crowded living conditions
 Spray for ticks fleas mites
 Practice good hygeine
 Care farmers working in farms,in
bushes,andthose who are close to
rodents,domestic animals etc.
 NO VACCINE at present