Plague is a bacterial disease caused by Yersinia pestis that is typically transmitted between animals and humans by fleas. It has caused several pandemics throughout history that have killed millions. The document discusses the three main plague pandemics, symptoms and forms of plague, transmission between animals and humans, diagnosis, treatment, and prevention including vaccination and controlling rodent and flea populations.

1. PLAGUE
Dr. Shwetha
Associate Professor
Dept. Of Community Medicine

2. INTRODUCTION
 Zoonoses: Yersinia pestis, rodents and fleas
 virulent & potentially lethal bacterial disease
 Presents: three major forms bubonic,
pneumonic,
septicaemia
 other forms enzootically, epizootically,
sporadically and in epidemics of all types.
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3. HISTORY
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• One of the 3 WHO quarantinable diseases
• Estimated 200 million deaths recorded
• 3 major pandemics
Justinian plague
Black death or Great Plague
Modern Plague/ China plague

4. THE THREE MAJOR PLAGUE PANDEMICS
 Justinian plague:
First recorded in 541AD
killed 100 million people
Affected virtually all of the known world at
that time.
 Black death or Great Plague:
 Originated in China in 1334 and
 spread along the great trade routes to Europe
 60% of the European population
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5.  Modern Plague:
 third pandemic also began in China in the
1860s and appeared in Hong Kong by 1894,
over the next 20 years it spread to port cities
around the world by rats on steam ships and
caused approximately 10 million deaths.
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6. 6

7. “Ring Around The Rosy
A Pocket Full Of Posies,
Ashes Ashes All Fall Down”
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8. PROBLEM STATEMENT
 Globally : 2013, 783 cases, 126 deaths.
 Acc. to WHO: 20 countries in Africa, America,
and Asia are identified as natural foci for
plague
The 3 most endemic countries: Madagascar,
the Democratic Republic of Congo and Peru.
In Madagascar, outbreaks have occurred
nearly every year since 1980. 4

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10.  India : outbreak in 1994
 Maharashtra state (bubonic type) and
district Surat in Gujarat state (pneumonic)
 In 2004, Uttarkashi:
localized outbreak of bubonic plague
(8 cases and 3 deaths)
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11. AGENT FACTORS
AGENT:-Yersinia pestis: Alexandre Yersin, 1894
 11 Yersenia species: 3 human pathogens
Y. Pestis, Y. Psuedotuberculosis, Y. Entercolitica
 Family: ENTEROBACTERIACEA
 gram negative, nonmotile, nonsporulating
coccobacillus that exhibits bipolar staining.
 Glycoprotein F1 acts as a virulence factor & also a
principal immunodiagnostic marker of infection.
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12. YERSINIA PESTIS
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The bipolar
staining of
the Yersinia
pestis
 gram negative, nonmotile, nonsporulating
coccobacillus that exhibits bipolar staining.
 Glycoprotein F1 acts as a virulence factor & also
a principal immunodiagnostic marker of infection

13. RESERVOIR OF INFECTION
 Wild rodents are the natural reservoirs of
plague e.g.. Field mice, skunks and other
small animals.
 In India : wild rodent, main reservoir not the
domestic rat as once thought.
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14. PLAGUE IN RODENTS
rodents
commensal
domestic
peridomestic
wild
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 Out of 1700 species of rodents, 200 are associated
with plague.
 Rodents : two different groups

15.  Wild plague- existing in nature independent of
human population and their activities.
 disease spreads among wild rodents by wild
rodent fleas
 Domestic plague- intimately associated with man
& rodents living with him.
 Long persistence of plague: survival of rat fleas in
the burrows for as long as 4 years.
 Other mechanisms –
1. survival of the bacilli in the burrows,
2. development of resistance &
3. localization of the bacilli in some organs etc..
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16. SOURCE OF INFECTION
 Infected rodents,
 rat flea and
 a case of pneumonic plague.
 Dogs and cats may be infected with
Y.pestis by eating infected rodents
and by being bitten by infected fleas.
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17. VECTOR OF PLAGUE
 commonest & efficient vector: rat flea(X. Cheopis)
 Both sexes of flea bite & transmit the disease.
 Yersinia pestis multiplies enormously in the foregut
of fleas
 blocked flea
 Semi blocked flea/Partially blocked flea
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18. Xenopsylla Cheopis
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19. HOST FACTORS
 AGE AND SEX FACTORS:-all ages and both sexes
 HUMAN ACTIVITIES:-hunting,
grazing,
harvesting
cultivating
constructional activities
recreational activities
 MOVEMENT OF PEOPLE:- sea or land or air
 IMMUNITY:- no natural immunity in human. Immunity
after recovery is relative 15

20. ENVIRONMENTAL FACTORS
 SEASON:- varies in different parts of country
Northern India:plague season is from September to
May.
South: disease is found active all around the year.
 TEMPERATURE AND HUMIDITY:-
o mean temperature of 20-25deg.C and
o humidity above 60% is favourable
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21. MODE OF TRANSMISSION
COMMEN-SAL
RATS RAT FLEAS MAN
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WILD
RODENT
WILD RODENT
FLEA/DIRECT
CONTACT
MAN
MAN
HUMAN
FLEA
MAN
MAN MAN

22. INCUBATION PERIOD
 Bubonic plague- 2 to 7 days
 Septicaemic plague- 2 to 7 days
 Pneumonic plague- 1 to 3 days.
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23. Y.PESTIS AS A BIOWEAPON
 Plague was thought to be a excellent bioweapon
because of its-
1. highly contagious nature,
2. high mortality
3. and ability to produce significant number of
secondary cases of the primary pneumonic plague
due to person to person transmission via
respiratory aerosols.
 The bacilli remains viable for 1 hr and can be
dispersed for distances upto 10 km
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24. DIAGNOSIS BY CLINICAL FEATURES
Bubonic plague-Features like sudden onset of
fever, chills, headache, prostration, painful
lymphadenitis, tender enlarged lymph nodes
(buboes in the groin, axilla or neck) raise a
suspicion of bubonic plague
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25. Pneumonic plague- sudden onset of fever ,
dyspnoea , cough with expectoration ,
copious blood stained frothy infective
sputum
Septicemic plague- patient is toxic and may
have gastrointestinal symptoms such as
nausea , vomiting, abdominal pain and
diarrhoea .
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26. LABORATORY INVESTIGATION
STAINING- of clinical materials (bubo fluid ,
sputum) by Giemsa or Wayson’s stain to
demonstrate bipolar bacilli
CULTURE- of blood to isolate plague bacilli.
Brain-heart infusion broth, sheep blood agar and
Macconkey agar are culture media used.
Cary-Blair media is commonly used as transport
medium.
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27. LABORATORY INVESTIGATION (CONT)
SEROLOGY- for antibody studies .
ELISA and PCR
OTHER METHODS- inoculation of clinical
specimen into guinea pig and mice
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28. FLEA INDEX
Total flea index: avg. no. of fleas of all species/rat
Cheopis index (CI): avg. no. of X. cheopis per rat
 More significant index than TFI
 CI > 1: Indication of plague outbreak
Specific percentage of fleas: % of different species of
fleas on rats
Burrow index: avg. no. of free living
fleas/species/rodent burrow
FLEAS INDICES SERVE AS A WARNING FOR EPIDEMICS
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29. PREVENTION AND CONTROL
CONTROL OF CASES
a) Early diagnosis
b) Notification-If human or rodent case is
diagnosed health authority should be
notified promptly
c) Isolation-Especially in case of suspected and
confirmed pneumonic plague.
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30. TREATMENT
STREPTOMYCIN (30mg/kg/BW daily IM two divided
dose for 7 to 10days): DOC
TETRACYCLINE (30-40mg/kg/BW daily), alternative
drug
GENTAMYCIN (2mg/kg/BW loading dose then
1.75mg/kg/BW every 8th hourly IV)
SULFONAMIDES may be used
DISINFECTION of sputum and articles soiled by
patient.
Dead bodies of rats should be handled with
aseptic precautions 31

31. FLEA CONTROL
INSECTICIDES
 DDT(10%), BHC(3%) are commonly used
 Effective: 2-4 months
 In resistance to DDT/BHC: CARBARYL (2%)
MALATHION (5%)
 Dose: 2 to 3g insecticide /Sq mt surface
 Inside house:: 3 feet above floor level
back of the door
roofing: thatched houses
crevices
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32. FLEA CONTROL (CONT)
Rat burrows should be insufflated with
insecticidal dust with the help of dust blowers
Within 48 hours of application, the flea index
should drop to zero.
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33. RODENT CONTROL
 general sanitation,
 housing and quality of life
 adequate anti rodent measures: mass destruction
TATERA INDICA
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34. ANTI RODENT MEASURES
Sanitation measures-
1. storage, collection and disposal of garbage
2. Proper storage of food stuff
3. rat proof buildings , godown & warehouses.
4. Elimination of rat burrows by blocking them
with concrete.
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35.  Trapping of rats
 Usage of rodenticides-Zinc phosphide,
Barium carbonate,Red squill, Nor bromide
 Fumigation –Carbon disulphide, Methyl
bromide, SO2 and cyanogas
 Chemosterilants
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36. VACCINATION
 formalin killed vaccine .
 Developed by HAFFKINE institute modified by
SOKHEY.
 Route – Subcutaneous
 Schedule - 2 doses (0.5 and 1ml) 7 to 14 days apart
 Immunity starts 5 to 7 days after inoculation and
last for about 6 months.
 Booster dose – once in 6 months for persons at risk
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37. CHEMOPROPHYLAXIS
 preventive measure.
 medical, nursing and public health personnel,
plague contacts at risk
 DOC: Tetracycline- 500mg 6th hrly for 5 days.
 Sulphonamide - 2 to 3 g daily for 5 to 7 days
(alternative)
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38. SURVEILLANCE
 In areas of natural plague foci or an
area with past infection of plague
1. microbiology,
2. serology,
3. entomology,
4. mamology,
5. epidemology and ecological
studies
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39. HEALTH EDUCATION
Reduce rodent habitat around your home, work
place and recreational areas.
Build rodent proof buildings and homes.
Use repellents if you think you could be exposed
to rodent fleas during camping or working
outdoors.
Prompt reporting of dead rats and suspected
case to health authorities.
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40. THANK YOU
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41. LEPTOSPIROSIS
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42. INTRODUCTION
Emerging infectious disease of Global importance
Caused by organism Leptospira
1.L.interrogans
2.L.biflexa
Leptospira are thin and light motile 0.1 - 0.2 u.m
wide and 5 - 15 u.m long with hooked ends.
Only the strains of L. interrogans are pathogenic.
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43. EPIDEMIOLOGICAL DETERMINANTS
Agent factors
Source : Organisms are excreted in Urine of
Infected animals
Reservoir : Both Wild & Domestic animals are
Rats & Small rodents
R.norvegicus & musmusculus
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Host factors:
1. Age : Children acquire infections more than adults
2. Occupation : Agriculturists, Livestock
farmers, workers in rice fields,
Underground sewers, Abattoir
workers, Meat handlers,
veterinarians.
3. Immunity : Specific immunity follows infection
4. Incubation period : 4 to 20 days

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46. ENVIRONMENTAL FACTORS
Out breaks :heavy rainfall and consequent flooding
Leptospira in the urine: survive for weeks in soil
and water
Environmental contamination may reach high levels
in areas where carrier animals frequently urinate
Contaminated urine and feces
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47. MODES OF TRANMISSION
 Direct contact
 Through skin abrasions/intact mucus
membrane
 Indirect contact
 Vegetation contaminated by infected urine
 Contaminated food and water consumption
 Droplet infection
 May occur through inhalation
 Man to Man : rare 48

48. CLINICAL FEATURES
Four main clinical syndromes
Bacteraemic leptospirosis
Aseptic meningitis
Icteric leptospirosis (weils disease)
Pulmonary syndrome
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50. CLINICAL FEATURES
Symptoms: Fever, chills, rash, jaundice,
haemorrhage, headache,
confusion, prostration, nausea
and vomiting
Signs: Lymphadenopathy, icterus,
hepatosplenomegaly, pharyngeal
injection, maculopapular rash
Complications: Aseptic meningitis,
chorioretinitis,
pulmonary haemorrhage 51

51. DIAGNOSIS
1. Isolation of organism: From blood during
acute illness and urine after the 1st week
of illness.
2. From urine: after 10th day- 6 weeks
3. Agglutination test:
Positive: 7-10 days of illness
Peek : 3-4 weeks
Persist for many years
IgM ELISA: for early diagnosis: positive, 2
days into illness 52

52. Demonstration of the organism: Dark
field microscopy
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53. Culture:
1. Liquid or semi solid medium like
Korthof’ Stuart’s and Fletcher’s media.
2. Semi synthetic media like EMJH media
Serology: Indirect heamagglutination test,
ELISA
immunofluorescent antibody assay
Lepto dipstick
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54. TREATMENT
Mild leptospirosis
Doxycycline (100 mg orally bid) or
Amoxicillin (500 mg orally tid) or
Ampicillin (500 mg orally tid)
Moderate/severe leptospirosis
Ceftriaxone (1 g/day intravenously)
or
Cefotaxime (1 g intravenously
6thhourly)
{Note : all regimens are given for 7 days} 55

55. CONTROL MEASURES
1. Environmental measures:-Preventing exposure
to contaminated water
2. Anti rodent measures: Elimination of rat
burrows, proper storage, collection and
disposal of garbage, trapping and use of
rodenticides
3. Health education
4. Protection of workers in hazardous occupation
5. Chemoprophylaxis: Doxycycline 200mg orally
once a week for 7 days. 56

56. VACCINES
 killed vaccine
 Lipopolysaccharide vaccine
 2 subcutaneous injection of 1ml at a
 7 days apart
 Booster:1 dose within 5 yrs of 2nd dose
 Not in INDIA
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