Scrub typhus, caused by Rickettsia tsutsugamushi, is prevalent in rural areas of endemic regions and is transmitted through infected larval mites. Clinical manifestations include fever, headache, and an eschar at the mite bite site, with treatment primarily using tetracycline. Murine typhus, caused by Rickettsia typhi, is related to rat infestations and spread through flea feces, presenting with milder symptoms and also treated with tetracycline.

1. SCRUB
TYPHUS

2. INTRODUCTION AND DISTRIBUTION
• One of the most widespread diseases among rickettsia disease
• Zoonoses in nature between certain species of trombiculid mites
and their small mammals (field mice, rats, shrews)
• Endemic in northern Japan, south east Asia, the western Pacific
Island, Eastern Australia, China, Maritime areas and several parts
of South central Russia, India, Sri Lanka.
• Most travel acquired cases of scrub typhus occur during visits to
rural areas in endemic countries for activities such as camping,
hiking or rafting, but urban cases have also been described

3. AGENT
Rickettsia tsutsugamushi
HOST
Reservoir: trombiculid mite
Host: rodents, man
ENVIRONMENT
Improper sanitation
Epidemiological
triad

4. MODE OF TRANSMISSION
• By the bite of infected larval mites
• Transmission cycle:
Mite Rat and mice Mite Rats and mice
Man
The disease is not directly transmitted from person to person
INCUBATION PERIOD
10-12 days, varies from 6-21 days

5. CLINICAL MANIFESTATION
• Resembles epidemic typhus clinically
• Onset is acute with chills and fever(104-105 ), headache, malaise,
℉
prostration and macular rash appearing around the 5th
day of illness
• Generalised lymph adenopathy and lymphocytosis
• Punched out ulcer covered with a blackened scab (eschar) which
indicates the location of mite bite
• The pyrexia falls by lysis in the 3rd
week in untreated cases
• The Weil Felix reaction is strongly positive with the proteus strain OXK

6. CONTROL MEASURES
TREATMENT
• Tetracycline is the drug of choice
VECTOR CONTROL
• Clearing the vegetation where rats and mice live
• Application of insecticide- Lindane, Chlordane to ground and vegetation
PERSONAL PROPHYLAXIS
• Impregnating clothes and blankets with miticidal chemicals(benzyl
benzoate) and application of mite repellent ( Diethyl toluamide) to
exposed skin surfaces
No vaccine exist at present

7. MURINE
TYPHUS
(endemic/ flea borne typhus)

8. DISTRIBUTION
• Murine typhus is a zoonoses distributed especially in areas of high
rat infestation
• It appears to be more prevalent in Southeast Asian and Western
Pacific countries than previously recognised
• Successful isolation of the causative agent from rats, fleas and
bandicoots was made at many places in India
• Focal infections are often associated with docks and shipping
places where rats abound

9. AGENT
Rickettsia typhi
HOST
Host: rodents, man
ENVIRONMENT
Summer month when rats
and flies are the most active
Epidemiological
triad

10. MODE OF TRANSMISSION
• Infection spread from rat to rat and possibly by rat louse
• Transmission is not by the bite of rat flea, but by
(i) Inoculation into skin of feces of infected fleas
(ii) Possibly by inhalation of dried infective feces
Rat Rat flea Rat rat flea
Man
The disease is not directly transmitted from person to person

12. CLINICAL MANIFESTATION
• Resemble that of louse borne typhus but, milder and rarely fatal
• Gradual onset fever, headache, myalgia, cough, rash ( 55% maculo-papular rash
on trunk)
• The Weil Felix reaction with proteus OX-19 becomes positive in the 2nd
week
INCUBATION PERIOD
1-2 weeks, commonly 12 days

13. CONTROL MEASURES
TREATMENT
• Tetracycline is the only drug of choice
• Since rickettsia growth is enhanced in the presence of sulphonamides,
these drugs should not be given
CONTROL OF FLEAS
• Residual insecticides- Benzene hexachloride, malathion are affective
against rat fleas
• Rodent control measures should be implemented in the affected areas
No vaccine exist at present