The document discusses rickettsial diseases in India, including scrub typhus which is the most common rickettsial infection in India transmitted by chiggers. It provides details on the classification, epidemiology, clinical presentation, diagnosis, and treatment of scrub typhus and other rickettsial diseases. Outbreaks of scrub typhus have been reported in several Indian states resulting in hundreds of cases and deaths.

1. RICKETTSIAL DISEASE IN
INDIA
DR PREETI ( PRESENTER)
DR ARTI (COLLABORATOR)
DR JUTANG (MODERATER)

2. OUTLINES
 INTRODUCTION
 HISTORY
 CLASSIFICATION
 EPIDEMIOLOGICAL DETERMINANT
 GLOBAL BURDEN
 STATE STATUS
 OUTBREAKS IN INDIA
 CLINICAL PRESENTATION
 SCRUB TYPHUS VS NON SCRUB
 LAB DIAGNOSIS
 TREATMENT

3. INTRODUCTION
 Gram-negative cocco bacilli
 Obligate Intracellular
 Non cultivable
 Life cycle circulating between mammalian
hosts and hematophagous arthropod vectors
 Human accidental host
 Contain both DNA and RNA
 Cell Wall contains - Outer Membrane +
Phoshoglyceride + Lipopolysaccharide
 Antigen Surface cell Ag
OMP A and B
LPS Ag

4. HISTORY
 Hippocrates (460 BC)
 Typhus‘confused state of the intellect’associated with fevers.
– As ‘febrile, exanthematic illness, associated with nervous system’
described in L’epidemion.
 Napoleone’s Grande Armee (in 1812)
– Reduced over 42 fold (from 422000 men to 10000men) during
invasion of Russia
– Majority dying from typhus rather than combat.

5. HISTORY
 The Second World War (1942‐1945)
– Scrub typhus: 18000 cases and 639 deaths
– Murine typyphus: 787 cases and 15 deaths
During outbreaks in armies, ships and prison,
– Burning of clothes
– Changing of bedding
– Crude quarantine measures

6. HISTORY
 Charles Nicole (in 1909)
– Demonstrated Pediculus corporis (body louse) was
the vector of epidemic typhus
In 19th Century, ill‐defined entity of ‘typhus’was dissected into triad
of
– Typhus
– Typhoid
– Relapsing fevers

7. HISTORY
 Oldest and most devastating ailments
 Epidemics during times of war and famine
 Von Prowazek and da Rochalima in Europe and Howard
Ricketts in Mexico identified the causative agent of
louse-borne typhus
 Rickettsial infection was initially seen in epidemic form
during World War II. In 1965, and 1990, it resurged.

8. The famous Rickettsiologists
Stanislaus Von Prowazek Howard Taylor Ricketts Charles Nicolle with collaborators
Helen Sparrow and Rudolph Weig

9.  Order Rickettsiales: 2 Families with 6 genera
 Family Anaplasmataceae – Anaplasma
Ehrlichia
Neoehrlichia
Neorickettsia
 Family Rickettsiaceae – Rickettsia
Orientia,
CLASSIFICATION

10. CLASSIFICATION

11. CLASSIFICATION

12. PATHOGENESIS

13. VECTOR
EPIDEMIOLOGICAL DETERMINANTS

14. history of animal contact (dog/cattle) or insect bite.
Rural area
Age
EPIDEMIOLOGICAL DETERMINANTS

15. Case definition
Definition of suspected/clinical case:
• AUFI of 5 days or more with or without eschar should
be suspected as a case of rickettsial infection.
• Other presenting features may be headache
• Rash ( more often seen in fair persons),
• lymphadenopathy, multi-organ involvement and
acute respiratory distress.
EPIDEMIOLOGICAL DETERMINANTS

16. Definition of probable case:
A suspected clinical case showing titres of 1:80 or above
in OX2, OX19 and OXK antigens by weil-Felix test and an
optical density(Od) > 0.5 for IgM by ElISA is considered
positive for members of typhus and spotted fever groups
of Rickettsiae
EPIDEMIOLOGICAL DETERMINANTS

17. Definition of confirmed case:
A confirmed case is the one in which
(a) Rickettsial dNA is detected in eschar
samples or whole blood by PCR, or
(b) Rising antibody titres on acute and
convalescent serum samples detected by
indirect immune fluorescecnce assay (IFA).
EPIDEMIOLOGICAL DETERMINANTS

19. EPIDEMIOLOGICAL DETERMINANTS

20.  Scrub typhus is the commonest occurring rickettsial
infection in India.
 The infection is transmitted through the larval mites or
‘chiggers’ belonging to the family Trombiculidae.
 Only the larval stages take blood meal.
 Small rodents particularly wild rats of subgenus Rattus
are natural hosts .
 The field rodent and vector mites act as reservoir and
between the two the infection perpetuates in nature.
Scrub Typhus

21. Risk Factors
 Outdoor activities
 Travelers agricultural workers, forestry personnel
 Increased human-animal interactions
 sandy beaches, scrub vegetation, mountains, and equatorial rain
forests.
Scrub Typhus

22. Scrub Typhus

23. Scrub Typhus

24. Clinical Presentation
 CLASSICAL TRIAD Rash , Eschar and lymphadenopathy
 Incubation period can be from 6 to 20 days (Average 10 days)
 Papule followed by an eschar at the site of chigger feeding (only
in 50%)
Scrub Typhus

25. Epidemiology Globally
 They are endemic across extensive part of Asia, South Asia, Australia and
the Pacific.
 It is found in India, Pakistan, China, Thailand, Malaysia, Taiwan, Tibet,
Japan, Russia, South Korea and Nepal.
 These regions in which scrub typhus is endemic is referred as the
tsutsugamushi triangle.
 They were clinically described in the Far East more than 1500 years ago.
 Over 1 Billion people are living in endemic areas and as many as 1 million
are infected annually.
Scrub Typhus

26.  Equatorial rain forests, semi deserts and Alpine subarctic terrains
in the Himalayan regions
 Specific habitats such as abandoned plantations, gardens or rice
fields, overgrown forest clearings, shrubby fringes of fields and
forests, river banks and grassy fields. These ecological patches
which attract the natural host of mite vectors are called ‘mite
islands
Scrub Typhus
Epidemiology Globally – Mite Islands

27.  Scrub typhus is the commonest worldwide, causing an estimated
1,000,000 cases per year.
 Reported from several States in India including Jammu and
Kashmir, Himachal Pradesh, Uttaranchal (now Uttrakhand),
Bihar, West Bengal, Meghalaya, Rajasthan, Maharashtra,
Karnataka, Tamil Nadu and Kerala.
 In some regions scrub typhus accounts for upto 50 per cent of
undifferentiated fever presenting to hospital.
Scrub Typhus
Epidemiology India

28.  In this review, the epidemiology of scrub typhus within the
country and the regional distribution were heterogeneous with the
maximum proportion of cases being reported from South India
(55.5%) followed by North India (31.5%)
Scrub Typhus
Epidemiology India

29.  Eleven outbreaks have been reported from 2000 to 2011, with >900
cases and 42 deaths (case-fatality ratio 5%–17%) in Himachal
Pradesh, Manipur, and one each from Jammu to Kashmir, Tamil
Nadu, Pondicherry, West Bengal, and Meghalaya. Scrub typhus
caused all the outbreaks (exception Kangra: epidemic typhus).
 Cases have also been reported from Rajasthan, Uttaranchal, Assam,
Maharashtra, Kerala, and Karnataka.[8]
Scrub Typhus
Epidemiology India - Outbreaks

30. Devasagayam E, Dayanand
D, Kundu D, Kamath MS,
Kirubakaran R, Varghese GM
(2021) The burden of scrub
typhus in India: A
systematic review. PLoS
Negl Trop Dis 15(7):
e0009619.
https://doi.org/10.1371/jo
urnal.pntd.0009619

33. Complication
1. Most common: hepatitis (40.5% of cases of scrub typhus)
thrombocytopenia (28.4%),
2. acute respiratory distress syndrome or ARDS (20.5%),
3. acute kidney injury (19.2%),
4. meningitis (16.4%), shock (16.2%), and
5. myocarditis (15.5%).
Scrub Typhus

34. Devasagayam E, Dayanand D, Kundu D, Kamath MS, Kirubakaran R, Varghese GM (2021) The burden of scrub typhus in India: A systematic
review. PLoS Negl Trop Dis 15(7): e0009619. https://doi.org/10.1371/journal.pntd.0009619

35. Lab Diagnosis of Scrub Typhus
 Serologic tests
 SPECIFIC TEST Indirect immunoperoxidase assay (IPA) and
immunofluorescence assay (IFA) ,CFT
 Weil-Felix test
 MOLECULAR METHOD PCR and ELISA
 immunoglobulin M (IgM) capture assays
Scrub Typhus

36. Weil Felix Test
 Slide/Tube Agglutination test
 Heterophile Antigen
 This test should be carried out only after 5-7 days of
onset of fever. Titre of 1:80 considered possible infection.
Scrub Typhus

37. Scrub Typhus

38. Immunochromography Test
Scrub Typhus
 Rapid diagnostic test
 Detect IG M

39. Enzyme-linked immunosorbent assay
(ELISA)
 IgM and IgG ELISA:immunoglobulin M (IgM) capture assay
 Presence of IgM antibodies, indicates recent infection with
Rickettsia.
 IgM antibody titre is observed at the end of 1st week, whereas
IgG antibodies appear at the end of 2nd week. The cut-off value is
optical density of 0.5. Baseline titres need to be established
keeping in view the regional variations.
Scrub Typhus

40.  Polymerase chain reaction (PCR):
 Rapid and specific test. It detect rickettsial DNA in whole blood,
buffy coat fraction or tissue specimen.
 RTPCR is used to target the gene encoding the major 56 kDa
and/or 47 kDa surface antigens.
 Sensitive in first week for blood samples (because of presence of
rickettsemia (O. tsutsugamushi, R. rickettsii, R. typhi and R.
prowazekii) in first 7-10 days.)
Scrub Typhus

41.  Immunufluoroscence assay (IFA): ‘Gold standard’
 Recommended only for research and in areas where
seroprevalence of rickettsial diseases has been established
and a reference facility is already available
Scrub Typhus

42.  Indirect immunoperoxidase assay (IPA): It gives comparable result
as IFA but requires special instrument and experienced personnel
for interpretation of the test.
 Modification of IFA
Scrub Typhus

43. Supportive laboratory Investigations
 Leucocytosis is seen, i.e. WBC count > 11,000/μl.
 Thrombocytopenia (i.e. < 1,00,000/μl)
 Biochemistry: Raised transaminase levels
 Imaging: Chest X-ray shows infilterates, mostly
bilateral
Scrub Typhus

44.  Spotted fever group (SFG) rickettsioses
 Typhus group (TG)
NON Scrub Typhus Rickettsial Diseases

45. NON Scrub Typhus Rickettsial Diseases

46. Epidemic Typhus
Louseborne typhus, caused by R. prowazekii
Endemic Typhus
Fleaborne typhus, caused by R.typhi
Rocky Mountain spotted Fever
Tickborne SF, caused by R. rickettsia
NON Scrub Typhus Rickettsial Diseases

47. Epidemic Typhus
Louseborne typhus, caused by R. prowazekii
Endemic Typhus
Fleaborne typhus, caused by R.typhi
Rocky Mountain spotted Fever
Tickborne SF, caused by R. rickettsia
NON Scrub Typhus Rickettsial Diseases

48. Rocky Mountain spotted Fever
Tickborne SF, caused by R. rickettsia
fever, rash, headache, malaise, myalgia, nausea
history of tick exposure
NON Scrub Typhus Rickettsial Diseases

49. Epidemic Typhus
Louseborne typhus, caused by R. prowazekii
Starts with fever and chills.
• A characteristic rash appears
– on the fourth or fifth day,
– Starting on the trunk and spreading over the limbs but
sparing the face, palms and soles
NON Scrub Typhus Rickettsial Diseases

50. Epidemic Typhus
In some who recover from the disease, the
rickettsiae may remain latent in the lymphoid tissues
or organs for years
Such latent infection may at times be reactivated
leading to recrudescent typhus or Brill Zinsser disease
NON Scrub Typhus Rickettsial Diseases

51. Rickettsial disease (RDs) other than scrub
typhus (ST) in INDIA
 Documented before the centenary by Megaw (1917) in a
febrile case of a European male bitten by a tick on his
travels from Almora to Lucknow
 An outbreak of 12 cases recorded by Major E.S. Phipson
(1922) in Shimla investigated and documented using the
Weil–Felix reaction with the Bacillus proteus X19 strain
 Study from Kashmir in 1951 documented that up to 91% of
RDs were due to murine typhus
NON Scrub Typhus Rickettsial Diseases

52. NON Scrub Typhus Rickettsial Diseases

53. NON Scrub Typhus Rickettsial Diseases

54. PREVALENCE

55. Risk Factor
 Crowded Condition
 Refugees housed in camps, incarcerated populations)
 rarely reported among tourists
NON Scrub Typhus Rickettsial Diseases

61. Giemsa stain of Rickettsia rickettsia

62. LAB DIADNOSIS
 Serology traditionally the mainstay of diagnosis, although
this has been limited by cross-reactions among closely
related members and diminished sensitivity/utility in the
acute phase of illness
 Nucleic acid amplification tests using blood specimens or
tissue swabs/biopsy specimens, sequencing, and
 Mass spectrometry, have emerged in recent years for both
pathogen and vector identification

63. TREATMENT

64. TREATMENT