1. Arthropod-borne
Viral InfectionsDr.T.V.Rao MD
21-01-2018 Dr.T.V.Rao MD 1

2. • VECTOR BORNE VIRAL INFECTIONS - Vector-borne diseases are infections
transmitted by the bite of infected arthropod species, such as
mosquitoes, ticks, triatomine bugs, sandflies, and blackflies (. Arthropod
vectors are cold-blooded (ectothermic) and thus especially sensitive to
climatic factors. Weather influences survival and reproduction rates of
vectors in turn influencing habitat suitability, distribution and
abundance; intensity and temporal pattern of vector activity
(particularly biting rates) throughout the year; and rates of
development, survival and reproduction of pathogens within vectors.
However, climate is only one of many factors influencing vector
distribution, such as habitat destruction, land use, population migration
to Urban areas, pesticide application, and host density. Vector-borne
diseases are widespread in Europe. Majority of Asian countries and
African continent continue to suffer the most and are the best studied
diseases associated with climate change, which is presented in this
program file Many vector borne diseases are associated with Viral
infections, Many physicians miss the maters in the early stages as the
manifestation looks alike Bacterial infection treat with new generation
of antibiotics Hope a basic understanding on the diseases which prevail
in many regions of the world, a great priority
• Dr.T.V.Rao MD
21-01-2018 Dr.T.V.Rao MD 2

3. What Is An Arbovirus?
• Arbovirus = arthropod-borne viruses
• Arboviruses are maintained in nature
through biological transmission between
susceptible vertebrate hosts by blood-
feeding arthropods
• Vertebrate infection occurs when the
infected arthropod takes a blood meal
21-01-2018 Dr.T.V.Rao MD 3

4. Arboviral Infections.
• 100s of Arbovirus,
• Around 100 are Human pathogens,
• Prevalent in Temperate and Tropical
areas.
• Most common in tropics,
• Out of Many 10 are very important.
21-01-2018 Dr.T.V.Rao MD 4

5. Arthropod-borne Viruses
Arthropod-borne
viruses (arbovirus)
are viruses that can
be transmitted to
man by arthropod
vectors. “
21-01-2018 Dr.T.V.Rao MD 5

6. The WHO definition is as follows
• Viruses maintained in nature
principally, or to an important
extent, through biological transmission
between susceptible vertebrate hosts by
haematophagus arthropods or
through trans ovarian and possibly
venereal transmission in
arthropods.”
21-01-2018 Dr.T.V.Rao MD 6

7. Arbovirus belong to
• Arbovirus belong to three families
• 1. Toga viruses e.g. EEE, WEE, and VEE
• 2. Bunya viruses e.g. Sandfly Fever, Rift
Valley Fever, Crimean-Congo
Hemorrhagic Fever
• 3. Flavivirus e.g. Yellow Fever, dengue,
Japanese Encephalitis
21-01-2018 Dr.T.V.Rao MD 7

8. Disease Mechanisms of Toga viruses and Flavivirus
Viruses are cytolytic, except for rubella.
Viruses establish systemic infection and viremia.
Viruses are good inducers of interferon, which can account for the flulike
symptoms of infection.
Viruses, except rubella and hepatitis C, are arboviruses.
Flaviviruses can infect cells of the monocyte-macrophage lineage. Non-
neutralizing antibody can enhance flavivirus infection via Fc receptors on
the macrophage.
Flulike Syndrome Encephalitis Hepatitis Hemorrhage Shock
Dengue + + + +
Yellow fever + + + +
St. Louis encephalitis + +
West Nile encephalitis + +
Venezuelan encephalitis + +
Western equine encephalitis + +
Eastern equine encephalitis + +
Japanese encephalitis + +
21-01-2018 Dr.T.V.Rao MD 8

9. Man-Arthropod-Man Cycle
21-01-2018 Dr.T.V.Rao MD 9

10. Animal-Arthropod-Man Cycle
21-01-2018 Dr.T.V.Rao MD 10

11. INDIAN SCENARIO
Dr.T.V.Rao MD 1121-01-2018

12. Arthropod Vectors
Mosquitoes
Japanese encephalitis, dengue, yellow fever, St.
Louis encephalitis, EEE, WEE, VEE etc.
Ticks
Crimean-Congo hemorrhagic fever, various tick-
borne encephalitis's etc.
Sandflies
Sicilian sandfly fever, Rift valley fever.
21-01-2018 Dr.T.V.Rao MD 12

13. Examples of Arthropod Vectors
Aedes Aegyti
Assorted Ticks
Phlebotmine SandflyCulex Mosquito21-01-2018 Dr.T.V.Rao MD 13

14. Animal Reservoirs
In many cases, the actual reservoir is not known. The
following animals are implicated as reservoirs
Birds Japanese encephalitis, St Louis
encephalitis,
EEE, WEE
Pigs Japanese encephalitis
Monkeys Yellow Fever
Rodents VEE, Russian Spring-Summer
encephalitis
21-01-2018 Dr.T.V.Rao MD 14

15. Major Arboviral Diseases
1.Yellow fever
2.Dengue,
3.Japanese B Encephalitis,
4.St Louis Encephalitis,
5.Russian spring summer encephalitis.
6.Eastren Equine Encephalitis,
7.West Nile Fever,
8.Sand fly Fever
21-01-2018 Dr.T.V.Rao MD 15

16. Major Arboviruses That Cause
Encephalitis
• Flaviviridae
– Japanese encephalitis
– St. Louis encephalitis
– West Nile
• Togaviridae
– Eastern equine encephalitis
– Western equine encephalitis
• Bunyaviridae
– La Crosse encephalitis
21-01-2018 Dr.T.V.Rao MD 16

17. http://www.cdc.gov/ncidod/dvbid/arbor/schemat.pdf
21-01-2018 Dr.T.V.Rao MD 17

18. 21-01-2018 Dr.T.V.Rao MD 18

19. St. Louis Encephalitis
21-01-2018 Dr.T.V.Rao MD 19

20. St. Louis Encephalitis
• Flavivirus
• Most common
mosquito-
transmitted human
pathogen in the US
• Leading cause of
epidemic flaviviral
encephalitis
21-01-2018 Dr.T.V.Rao MD 20

21. Eastern Equine Encephalitis
• Togavirus
• Caused by a virus transmitted to
humans and horses by the bite of
an infected mosquito.
• 200 confirmed cases in the US
1964-present
• Average of 4 cases per year
• States with largest number of
cases – Florida, Georgia,
Massachusetts, and New Jersey.
• Human cases occur relatively
infrequently, largely because the
primary transmission cycle takes
place in swamp areas where
populations tend to be limited.
21-01-2018 Dr.T.V.Rao MD 21

22. Western Equine Encephalitis
• Togavirus
• Mosquito-borne
• 639 confirmed cases in
the US since 1964
• Important cause of
encephalitis in horses
and humans in North
America, mainly in the
Western parts of the US
and Canada
21-01-2018 Dr.T.V.Rao MD 22

23. La Crosse Encephalitis
• Bunyavirus
• On average 75 cases per year
reported to the CDC
• Most cases occur in children under
16 years old
• Zoonotic pathogen that cycles
between the daytime biting treehole
mosquito, and vertebrate amplifier
hosts (chipmunk, tree squirrel) in
deciduous forest habitats
• Most cases occur in the upper
Midwestern state, but recently cases
have been reported in the Mid-
Atlantic region and the Southeast
• 1963 – isolated in La Crosse, WI from
the brain of a child who died from
encephalitis
21-01-2018 Dr.T.V.Rao MD 23

24. Togaviridae
21-01-2018 Dr.T.V.Rao MD 24

25. Togaviridae
• The name
Togaviridae
derived from
Toga meaning
roman mantle or
clack refers to
the viral surface
21-01-2018 Dr.T.V.Rao MD 25

26. TOGAVIRIDAE
Chikungunya virus Infection
• 1952 Epidemic in Tanzania.
• Manifest as Bend Up with Severe
Joint pains.
• Spread from wild primates –
Mosquito-Man
• Appears , reappears,
21-01-2018 Dr.T.V.Rao MD 26

27. Indian outbreaks
• The virus first appeared in India in
1958 the virus caused large
epidemics in Thailand
• In 1963 India Chikungunya
outbreaks occurred at irregular
intervals along the east coast of India
and in Maharashtra
21-01-2018 Dr.T.V.Rao MD 27

28. Viral Morphology
• Spherical 50 - 70
nm
• Bears the
Nucleocapsid, 42
capsomeres
• Positive sense ss
stranded RNA
21-01-2018 Dr.T.V.Rao MD 28

29. Prevalence of Chikungunya
21-01-2018 Dr.T.V.Rao MD 29

30. Transmission of Infection
21-01-2018 Dr.T.V.Rao MD 30

31. Man to Man infection with Mosquito
bites
• Chikungunya virus
requires an agent for
transmission and hence
direct human to human
transmission is not
possible. Usually
transmission occurs
when a mosquito bites
an infected person and
then later bites a non
infected person.
21-01-2018 Dr.T.V.Rao MD 31

32. Clinical Manifestations
•Crippling Joint pains
•Conjunctivitis
• Lymphadenopathy
•Hemorrhagic
tendencies.21-01-2018 Dr.T.V.Rao MD 32

33. Diagnosis
• Isolation of
viruses,
• Serology Ig M
• Nt and HI
tests,
21-01-2018 Dr.T.V.Rao MD 33

34. Control and Prevention.
• Mosquito control
• No vaccines,
• Other diseases like Chikungunya
1 Onyong Nyong Viruses
2 Simliki Forest Viruses
21-01-2018 Dr.T.V.Rao MD 34

35. Japanese B Encephalitis
21-01-2018 Dr.T.V.Rao MD 35

36. Japanese Encephalitis belongs to
Genus Flavivirus
• Flaviviridae
– Flavivirus
• The name is derived from
the Latin ‘flavus’
– Flavus means “yellow”
• Refers to yellow fever virus
• Enveloped
• Single stranded RNA virus
• Morphology not well
defined
Dr.T.V.Rao MD21-01-2018 36

37. Flaviviridae
Genus – Flavivirus,
• Important Diseases,
1. St Louis encephalitis,
2.Ilheus virus
3.West Nile Virus,
4.Murray valley encephalitis,
5.Japanese B encephalitis,
21-01-2018 Dr.T.V.Rao MD 37

38. Japanese Encephalitis
• First discovered and originally restricted to Japan. Now large scale
epidemics occur in China, India and other parts of Asia.
• Flavivirus, transmitted by culex mosquitoes.
• The virus is maintained in nature in a transmission cycle involving
mosquitoes, birds and pigs.
• Most human infections are subclinical: the in apparent to clinical cases
is 300:1
• In clinical cases, a life-threatening encephalitis occurs.
• The disease is usually diagnosed by serology. No specific therapy is
available.
• Since Culex has a flight range of 20km, all local control measures will fail.
An effective vaccine is available.
21-01-2018 Dr.T.V.Rao MD 38

39. History
• 1870s: Japan
–“Summer encephalitis” epidemics
• 1924: Great epidemic in Japan
–6,125 human cases; 3,797 deaths
• 1935: First isolated
–From a fatal human encephalitis case
• 1938: Isolated from Culex
tritaeniorhynchus
Dr.T.V.Rao MD21-01-2018 39

40. Genus - Flavivirus
• Japanese B encephalitis
virus is
Spherical, 40 – 60 nm in
diameter
Contain a positive sense
Single stranded RNA, 11 kb
in size
RNA genome is infectious
Several viruses in this group
are related.
Dr.T.V.Rao MD 4021-01-2018

41. Japanese B virus Infection
Infection is caused by a flavivirus, a single
stranded RNA virus. It is transmitted by
the bite of the Culex tritaeniorhynchus
mosquito. The virus multiplies at the site
of the bite and in regional lymph nodes
before viraemia develops. Viraemia can
lead to inflammatory changes in the
heart, lungs, liver, and
reticuloendothelial system.
Dr.T.V.Rao MD 4121-01-2018

42. Structure of Virus
• The outer envelope is
formed by envelope (E)
protein and is the protective
antigen. It aids in entry of
the virus to the inside of the
cell. The genome also
encodes several non-
structural proteins also
(NS1,NS2a,NS2b,NS3,N4a,N
S4b,NS5). NS1 is produced
as secretary form also. NS3
is a putative helicase, and
NS5 is the viral polymerase.
Dr.T.V.Rao MD 4221-01-2018

43. A Flavivirus
• Japanese encephalitis ( previously
known as Japanese B encephalitis is a
disease caused by the mosquito-borne
Japanese encephalitis virus. The
Japanese encephalitis virus is a virus
from the family Flaviviridae. Domestic
pigs and wild birds are reservoirs of the
virus; transmission to humans may occur
Dr.T.V.Rao MD 4321-01-2018

44. INDIAN SCENARIO
• Japanese encephalitis ( previously known
as Japanese B encephalitis is a disease
caused by the mosquito-borne Japanese
encephalitis virus. The Japanese
encephalitis virus is a virus from the
family Flaviviridae. Domestic pigs and
wild birds are reservoirs of the virus;
transmission to humans may occur
Dr.T.V.Rao MD 4421-01-2018

45. History
• 1940-1978
–Disease spread with epidemics in China,
Korea, and India
• 1983: Immunization in South Korea
–Started as early as age 3
–Endemic areas started earlier
• 1983-1987: Vaccine available in U.S. on
investigational basis
Dr.T.V.Rao MD21-01-2018 45

46. A leading cause of viral
Encephalitis
• Japanese
encephalitis is the
leading cause of viral
encephalitis in Asia,
with 30,000–50,000
cases reported
annually. Case-
fatality rates range
from 0.3% to 60%
and depends on theDr.T.V.Rao MD 4621-01-2018

47. Animal-Arthropod-Man Cycle
21-01-2018 Dr.T.V.Rao MD 47

48. Cycle of Infection in Japanese B Viral
Infection
Dr.T.V.Rao MD 4821-01-2018

49. Transmission
• Vector-borne disease
• Enzootic cycle
– Mosquitoes: Culex species
• Culex tritaeniorhynchus
– Reservoir/Amplifying hosts
• Pigs, bats
• Ardeid (wading) birds
• Possibly reptiles and amphibians
– Incidental hosts
• Horses, humans, others
Dr.T.V.Rao MD21-01-2018 49

50. A Vector born- Arbovirus Infection
• Culex tritaeniorhynchus
a rural Mosquito that
breeds in rice fields, is
the principle vector.
In India in 1955 the virus
were isolated from
Culex vishnui
mosquitoes in Vellore
region in Tamil Nadu
Dr.T.V.Rao MD 5021-01-2018

51. Japanese Encephalitis (JE)
• Most important global
cause of arboviral
encephalitis with > 50,000
cases and 15,000 deaths
reported each year.
• Only about 1 in 250 JE
infections result in
symptomatic illness.
• Primarily affects children 1
to 15 years of age.
• Incubation period is 5 to 14
days.
• If unrecognized, mortality is up to 30% with half of
survivors sustain severe neurological sequelae.
21-01-2018 Dr.T.V.Rao MD 51

52. INCIDENCE
• Leading cause of viral encephalitis in Asia
with 30-50,000 cases reported annually
• Fewer than 1 case/year in U.S. civilians
and military personnel travelling to and
living in Asia
• Rare outbreaks in U.S. territories in
Western Pacific
Dr.T.V.Rao MD 5221-01-2018

53. Dr.T.V.Rao MD 5321-01-2018

54. Cycle of Events in Japanese B
Encephalitis
Dr.T.V.Rao MD 5421-01-2018

55. Pass through two prominent Hosts
• Herons act as reservoir
hosts and pigs as
amplifier hosts.
• Human infection is a
tangential ‘dead end’
and infections are
spread when the
infected mosquitoes
reach high density.
Dr.T.V.Rao MD 5521-01-2018

56. Clinical Manifestations
• The incubation period is 6 to 16 days.
• There is a prodrome of fever, headache, nausea,
diarrhoea, vomiting, and myalgia, which may last for
several days.
• This may be followed by a spectrum of neurological
disease ranging from mild confusion, to agitation, to
overt coma.
• Two thirds of patients have seizures. It is more
common in children, while headache and meningism
are more common in adults.
Dr.T.V.Rao MD 5621-01-2018

57. Lethargy
Sudden fever
Vomiting and
diarrhea
Tremors or
convulsions
Headache Change in
consciousness
Irritability or
restlessness
Common symptoms of encephalitis
21-01-2018 Dr.T.V.Rao MD 57

58. Can lead to Neurological damage
• Tremor or other involuntary movements
are common.
• Mutism has been described as a
presenting symptom. So has a syndrome
of acute flaccid paralysis.
• Fever resolves by the second week, and
choreoathetosis or extra pyramidal
symptoms develop as the other
neurological symptoms disappear.
Dr.T.V.Rao MD 5821-01-2018

59. Diagnosis of Japanese B Encephalitis
• The isolation of virus from Blood, CSF,
or tissues.
• Detection of Arbovirus specific RNA in
blood,CSF, or Tissue
• However very few reference laboratories
can perform the isolation in view of the
biosafety considerations
Dr.T.V.Rao MD 5921-01-2018

60. Serology by ELISA
• IgM capture enzyme-linked immunoassay (ELISA) of
serum or CSF is the standard diagnostic test.
Sensitivity is nearly 100% when both serum and CSF
are tested. False-negatives may result if the samples
are tested too early, as in the first week of illness.
• New IgM dot enzyme immunoassays for CSF and
serum are portable and simple tests that can be used
in the field. Compared with ELISA as the gold
standard, the sensitivity and specificity are around
98 and 99% respectively.
Dr.T.V.Rao MD 6021-01-2018

61. Arbovirus Specific RNA detection
• Viral RNA is extracted from serum or from
suspected tissues of the patients or mosquito
homogenates.
• The product is amplified by RTPCR and the
products analyzed by restriction digestion and
determined by nucleotide sequence of PCR
product.
• The identified sequence is compared with
nucleotide sequence found in Gene bank or
other data bases
Dr.T.V.Rao MD 6121-01-2018

62. Japanese Encephalitis B Vaccine
• Japanese Encephalitis B Vaccine has been
produced since 1992. The vaccine is effective
but not without risks and the substantial risks
of the disease and the risks of the vaccine
have to be balanced, especially for stays of
brief duration. These are discussed more fully
in the article on that subject.
As with malaria, prophylaxis must be
supplemented by techniques to avoid being
bitten by mosquitoes.
Dr.T.V.Rao MD 6221-01-2018

63. Preventive measures
• Preventive measures include mosquito control
and locating piggeries away from human
dwellings
• A formalin inactivated mouse brain vaccine
using the Nakayama strain has been employed
in human immunization in Japan – Two doses
at two week’s interval followed by a booster 6
– 12 months later constitute a full course.
• However the immunity was short lived
Dr.T.V.Rao MD 6321-01-2018

64. Emerging Vaccines for JE virus
• Two vaccines are manufactured and distributed
exclusively in People’s Republic of China
– Inactivated vaccine grown in primary hamster kidney cells
– Live attenuated vaccine (SA14-14-2) grown in hamster
kidney cells
• The third is manufactured in Japan and distributed
abroad by arrangement with Sanofi-Pasteur
– Licensed as JE-VAXR and is the only FDA approved vaccine
for use in the U.S.
– Has been in wide use worldwide since the 1960’s
– Three subcutaneous injections over a month with a
booster at 3 years
– 91% efficacy in a large field trial in Thailand21-01-2018 Dr.T.V.Rao MD 64

65. Vaccination
• Live attenuated vaccine
– Used in equine and swine
– Successful for reducing incidence
• Inactivated vaccine (JE-VAX)
• Used for humans
• Japan, Korea, Taiwan, India, Thailand
• Used for endemic or epidemic areas
– Recommended for travelers
• Visiting endemic areas for > 30 days
Dr.T.V.Rao MD21-01-2018 65

66. Later vaccines
• A live attenuated vaccine has been developed
in China from JE strain SA 14-14-2, passed
through weanling mice
• The vaccine is produced in primary bay
hamster kidney cells.
• Administered in two doses, one year apart,
the vaccine has been reportedly effective in
preventing clinical disease
Dr.T.V.Rao MD 6621-01-2018

67. Prevention
• Vector control
– Eliminate mosquito breeding areas
– Adult and larvae control
• Vaccination
– Equine and swine
– Humans
• Personal protective measures
– Avoid prime mosquito hours
– Use of repellants containing DEET
Dr.T.V.Rao MD21-01-2018 67

68. Yellow Fever,
Flaviviridae - Family
•Mosquito Borne disease
•Present in Africa, Central
and South America.
•Absent in India.
21-01-2018 Dr.T.V.Rao MD 68

69. 21-01-2018 Dr.T.V.Rao MD 69

70. Flavivirus
• Spherical 40-60 nm in diameter
glycosylated. Diameter,
• Ss-RNA positive sense
• Three or Four structural polypeptides,
Two are glycosylated.
• Replicates in Cytoplasm.
• Produces Councilman bodies
21-01-2018 Dr.T.V.Rao MD 70

71. 21-01-2018 Dr.T.V.Rao MD 71

72. Pathogenesis and Pathology
• Mosquito ( Ades aegypti )Through skin-
Lymphatic's, Lymph nodes, circulation liver,
Spleen, Kidney, Bone marrow, Lymph glands.
Necrotic lesions in liver , kidney,
Mid zone – liver
Fatty degeneration – kidney,
Hemorrhages/Circulatory collapse.
Injury to Myocardium
21-01-2018 Dr.T.V.Rao MD 72

73. Clinical Features
• Incubation period 3-6 days,
• Fever, chills,
• Intoxication, Fever, Jaundice
• Clotting disorders,
• Mortality > 20%
• May recover totally
21-01-2018 Dr.T.V.Rao MD 73

74. Laboratory Diagnosis
• Intracerebral inoculation,
• Mosquito cell lines,
• P C R
• Serology –
ELISA Ig M Raise of titers,
21-01-2018 Dr.T.V.Rao MD 74

75. Immunity and Epidemiology
• Nt Antibodies protects,
• Epidemiology
Urban yellow fever,
Jungle yellow fever. Monkey,
Not Invaded Asia Not present in India.
21-01-2018 Dr.T.V.Rao MD 75

76. Treatment and Prevention.
• No Antiviral drugs,
• Mosquito control
• Vaccine 17 D strain of yellow fever vaccine.
• A single dose protect 95% of vaccinated.
• Not to be given in infants < 9 months age.
21-01-2018 Dr.T.V.Rao MD 76

77. Viral Hemorrhagic Fevers
CDC, AFIP
21-01-2018 Dr.T.V.Rao MD 77

78. Viral Hemorrhagic Fevers
• Diverse group of illnesses caused by RNA viruses from 4
families:
– Arenaviridae, Bunyaviridae, Filoviridae, Flaviridae
– Differ by geographic occurrence and vector/reservoir
– Share certain clinical and pathogenic features
• Potential for aerosol dissemination, with human
infection via respiratory route (except dengue)
• Target organ: vascular bed
• Mortality 0.5 - 90%, depending on agent
21-01-2018 Dr.T.V.Rao MD 78

79. Viral Hemorrhagic Fevers
• Category A agents
– Filoviruses
– Arenaviruses
• Category C agents
– Hantaviruses
– Tick-borne hemorrhagic
fever viruses
– Yellow fever
21-01-2018 Dr.T.V.Rao MD 79

80. Tick Borne Encephalitis
• Russian spring summer
encephalitis,
• Contact with sheep
• Produces mild aseptic meningitis,
• Bite of Ixodid Ticks,
• Avoid Tick bites,
21-01-2018 Dr.T.V.Rao MD 80

81. Viral Hemorrhagic Fevers
Transmission
• Zoonotic diseases
– Rodents and arthropods main reservoir
– Humans infected via bite of infected arthropod, inhalation of
rodent excreta, or contact with infected animal carcasses
• Person-to-person transmission possible with
several agents
– Primarily via blood or bodily fluid exposure
– Rare instances of airborne transmission with arenaviruses and
filoviruses
• Rift Valley fever has potential to infect domestic
animals following a biological attack
21-01-2018 Dr.T.V.Rao MD 81

82. Viral Hemorrhagic Fevers
Clinical Presentation
• Clinical manifestations nonspecific, vary by agent
• Incubation period 2-21 days, depending on agent
• Onset typically abrupt with filoviruses,
flaviviruses, and Rift Valley fever
• Onset more insidious with arenaviruses
21-01-2018 Dr.T.V.Rao MD 82

83. Viral Hemorrhagic Fevers
Initial Symptoms
– High fever
– Headache
– Malaise
– Weakness
– Exhaustion
– Dizziness
– Muscle aches
– Joint pain
– Nausea
– Non-bloody diarrhea
Prodromal illness lasting < 1 week may include:
21-01-2018 Dr.T.V.Rao MD 83

84. VHF Surveillance:
Clinical Identification of Suspected Cases
• Clinical criteria:
– Temperature 101 F(38.3 C) for <3 weeks
– Severe illness and no predisposing factors for
hemorrhagic manifestations
– 2 or more of the following:
• Hemorrhagic or purple rash
• Epistaxis
• Hematemesis
• Hemoptysis
• Blood in stools
• Other hemorrhagic symptoms
• No established alternative diagnosis
JAMA 2002;287
Adapted from WHO
21-01-2018 Dr.T.V.Rao MD 84

85. Viral Hemorrhagic Fevers
Treatment
• Supportive care
• Correct coagulopathies as needed
• No antiplatelet drugs or IM injections
• Investigational treatments, available under protocol:
– Ribavirin x 10 days for arenaviridae and bunyaviridae
– Convalescent plasma w/in 8d of onset for AHF
21-01-2018 Dr.T.V.Rao MD 85

86. Viral Hemorrhagic Fevers
Management of Exposed Persons
• Medical surveillance for all potentially exposed persons,
close contacts, and high-risk contacts (i.e., mucous
membrane or percutaneous exposure) x 21 days
– Report hemorrhagic symptoms (slide 47)
– Record fever 2x/day
• Report temperatures  101F(38.3C)
 Initiate presumptive ribavirin therapy
• Percutaneous/mucocutaneous exposure to blood or
body fluids of infected:
– Wash thoroughly with soap and water, irrigate mucous membranes with
water or saline
21-01-2018 Dr.T.V.Rao MD 86

87. Viral Hemorrhagic Fevers
Infection Control
• Airborne & contact precautions for health care, environmental, and
laboratory workers
• Negative pressure room, if available
– 6-12 air changes/hour
– Exhausted outdoors or through HEPA filter
• Personal protective equipment
– Double gloves
– Impermeable gowns, leg and shoe coverings
– Face shields and eye protection
– N-95 mask or PAPR
21-01-2018 Dr.T.V.Rao MD 87

88. Tick Borne Hemorrhagic Fevers
• Kyasanur Forest Disease,
• ( Karnataka India )
• Like Russian Spring Summer Encephalitis,
• Present with
Fever, Headache, Conjunctivitis,
Myalgia, Severe prostration,
21-01-2018 Dr.T.V.Rao MD 88

89. Viral Hemorrhagic Fevers
Infection Control
• Dedicated medical equipment for patients
• If available, point-of-care analyzers for routine
laboratory analyses
– If unavailable, pretreat serum w/Triton X-100
– Lab samples double-bagged & hand-carried to lab
• Prompt burial or cremation of deceased with
minimal handling
– Autopsies performed only by trained personnel with
PPE
21-01-2018 Dr.T.V.Rao MD 89

90. Viral Hemorrhagic Fevers
Summary of Key Points
• A thorough travel and exposure history is key to
distinguishing naturally occurring from
intentional viral hemorrhagic fever cases.
• Viral hemorrhagic fevers can be transmitted via
exposure to blood and bodily fluids.
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91. Pathogenesis.
• Enters through the bite of Insect vector,
• Multiply in RES.
• Target the organ
CNS Encephalitis,
Liver Yellow fever,
Capillary endothelium in
Hemorrhagic fevers.
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92. Kyasanur Forest Fever ( cont )
• Also called as Monkey fever,
• Associated with felling of virgin
forests,
• Tick Bite – Vector – Haemaphysalis
spinigera spread the disease
• Vaccine on trail
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93. Rodent Borne Hemorrhagic
Fevers,
•Hanta Virus, Produces
pulmonary infections in
USA
•Belong to Bunya Virus –
Hanta Viruses
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94. Hanta Viruses,
• Human disease Hemorrhagic fever with renal
syndrome
• Hanta virus pulmonary syndrome.
• Spread by inhalation of Aerosols of Rodent
Excreta,
• Renal Involvement and failure
• Lead to Hemorrhagic shock, Korea
• Spread by Rats carried in ships,
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96. Laboratory Diagnosis
• Detection of viral nucleic acid,
• Grown in culture lines,
• PCR, Rodent control
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97. Filoviruses,
African Hemorrhagic Fevers.
• Most important Diseases are
• Marburg and Ebola.
• The nature of Viruses are 80 nm
Filamentous threads,
• Produce Internal and external
Bleeding.
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98. Filoviruses. Marburg
• Marburg 1967 African Green
Monkey,
• Bat – Rodent – Host Human.
• East Africa Monkey – Humans.
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99. Filoviruses - Ebola
• Incubation 2-21 days
• Carries 80% mortality.
• Barrier Nursing Most essential.
• ELISA test
• Culturing Hazardous.
• RT-PCR
• Transporting and carrying Primates is
Hazardous
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101. • Program created by Dr.T.V.Rao MD for
Medical and Paramedical students in
the Developing World
• Email
• doctortvrao@gmail.com
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