Viral hemorrhagic fevers.pptx

azad82d@gmail.com
azad.haleem@uod.ac
Dr.Azad A Haleem AL.Mezori
FRCPCH,DCH, FIBMS
Assistant Professor
University Of Duhok
College of Medicine
Pediatrics Department
Viral hemorrhagic fevers
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Introduction
• Viral hemorrhagic fevers (VHFs) are a group of
diseases that are caused by several distinct families of
viruses.
• The term “viral hemorrhagic fever” refers to a
condition that affects many organ systems of the body,
damages the overall cardiovascular system, and
reduces the body’s ability to function on its own.
• Symptoms of this type of condition can vary but often
include bleeding, or hemorrhaging.
• Some VHFs cause relatively mild illness, while others
can cause severe, life threatening disease.

Etiology
• Although VHFs are caused by several families of
viruses, these viruses share some common
characteristics:
o They are RNA viruses,
o These viruses are the most common cause of emerging
disease in people because RNA viruses change over
time at a high rate.
o They are covered, or enveloped, in a lipoprotein outer
layer, making it easier to destroy these viruses with
physical (heat, sunlight, gamma rays) and chemical
(bleach, detergents, solvents) methods.

Etiology
• They naturally exist in animal or insect populations,
referred to as host populations, and are generally
restricted to the geographical areas where the host
species live.
• They spread to people when a person encounters an
infected animal or insect host.
• After the initial spread into the human population,
some VHF viruses can continue to spread from person-
to-person.
• Outbreaks of VHFs in people can be difficult to prevent
since they can occur sporadically and cannot be easily
predicted.

VHF diseases by virus family:
1.Arenavirus (order Bunyavirales)
•Chapare Hemorrhagic Fever (CHHF)
•Lassa Fever
•Lujo Hemorrhagic Fever (LUHF)
2.Flavivirus
•Alkhurma Hemorrhagic Fever (AHF)
•Kyasanur Forest Disease (KFD)
•Omsk Hemorrhagic Fever (OHF)
•Severe Dengue
•Yellow Fever
3.Filovirus
•Ebola Disease
•Marburg virus disease (MVD)
4.Hantavirus (order Bunyavirales)
•Hantavirus
• Hantavirus Pulmonary Syndrome (HPS)
• Hemorrhagic Fever with Renal Syndrome (HFRS)
5.Nairovirus (order Bunyavirales)
Crimean-Congo Hemorrhagic Fever (CCHF)
6.Phenuivirus (order Bunyavirales)
• Rift Valley Fever (RVF)

VHF Challenges
• More of the world’s population is at risk for
VHFs
• The number of viruses known to cause disease in
humans around the globe is ever-increasing, and
the way VHF viruses spread is likely to shift due to
globalization, international travel, and climate
change.
• Discovery and exploration of viruses and their
hosts is necessary to limit global spread and
disease burden.

VHF Challenges
• Person-to-person transmission of some VHFs can
occur
• VHF viruses can spread to people when they
come in contact with infected animals or insects.
• For many VHFs, person-to-person transmission
can then continue, often through direct contact
or in healthcare facilities without adequate
infection control procedures.

VHF Challenges
• Confirmation of VHF cases can take time
• Underdeveloped laboratories cannot rapidly diagnose
and confirm illnesses, leading to delays in isolating
infected people.
• Fast and accurate diagnostics are vital during outbreaks
to confirm VHF cases, leading to faster isolation of
cases and ultimately shorter, less severe outbreaks.
• Improving VHF diagnostic techniques to make them
faster, more accurate, and easier to produce and use is
an essential component to controlling these diseases.

VHF Challenges
• Prevention of VHF outbreaks is difficult
• Outbreaks of VHFs occur sporadically and
irregularly, and their occurrence can be difficult
to predict.
• Prevention is more difficult when the animal host
is unknown or challenging to control (such as
rodents or ticks).
• Strong risk communication and health education
efforts are required, focusing on exposure
prevention for communities and infection control
for healthcare providers.

VHF Challenges
• Availability of vaccines and treatments are
limited
• With limited effective vaccinations or drug
treatments available, some VHFs are treated only
with basic medical care, which is not always
adequate to prevent virus spread and save lives.
• It is important to understand how the virus infects
and spreads within the body to help guide the
development of treatments and new strategies to
protect against infection.

Crimean-Congo hemorrhagic fever (CCHF)
• Crimean-Congo hemorrhagic fever (CCHF) is
caused by infection with a tick-borne
virus (Nairovirus) in the family Bunyaviridae.
• The disease was first characterized in the Crimea
in 1944 and given the name Crimean
hemorrhagic fever.
• It was then later recognized in 1969 as the cause
of illness in the Congo, thus resulting in the
current name of the disease.

Crimean-Congo hemorrhagic fever (CCHF)
• Crimean-Congo hemorrhagic fever is found in
Eastern Europe, particularly in the former
Soviet Union, throughout the Mediterranean,
in northwestern China, central Asia, southern
Europe, Africa, the Middle East, and the
Indian subcontinent.

Transmission
• Ixodid (hard) ticks, especially those of the
genus, Hyalomma, are both a reservoir and a
vector for the CCHF virus.
• Numerous wild and domestic animals, such as
cattle, goats, sheep and hares, serve as
amplifying hosts for the virus.
• Transmission to humans occurs through contact
with infected ticks or animal blood.

Transmission
• CCHF can be transmitted from one infected
human to another by contact with infectious
blood or body fluids.
• Documented spread of CCHF has also
occurred in hospitals due to improper
sterilization of medical equipment, reuse of
injection needles, and contamination of
medical supplies.

Clinical manifestations
• The onset of CCHF is sudden, with initial signs and
symptoms including headache, high fever, back pain,
joint pain, stomach pain, and vomiting.
• Red eyes, a flushed face, a red throat, and petechiae
(red spots) on the palate are common.
• Symptoms may also include jaundice, and in severe
cases, changes in mood and sensory perception.
• As the illness progresses, large areas of severe bruising,
severe nosebleeds, and uncontrolled bleeding at
injection sites can be seen, beginning on about the
fourth day of illness and lasting for about two weeks.

Clinical manifestations
• In documented outbreaks of CCHF, fatality rates in
hospitalized patients have ranged from 9% to as high
as 50%.
• The long-term effects of CCHF infection have not been
studied well enough in survivors to determine whether
or not specific complications exist.
• However, recovery is slow.

Risk of Exposure
• Animal herders, livestock workers, and
slaughterhouse workers in endemic areas are at
risk of CCHF.
• Healthcare workers in endemic areas are at risk
of infection through unprotected contact with
infectious blood and body fluids.
• Individuals and international travelers with
contact to livestock in endemic regions may also
be exposed.

Diagnosis
• Laboratory tests that are used to diagnose
CCHF include:
• antigen-capture enzyme-linked
immunosorbent assay (ELISA),
• Real time polymerase chain reaction (RT-PCR),
• Virus isolation attempts, and detection of
antibody by ELISA (IgG and IgM).

Diagnosis
• Laboratory diagnosis of a patient with a clinical
history compatible with CCHF can be made during the
acute phase of the disease by using the combination of
detection of the viral antigen (ELISA antigen capture),
viral RNA sequence (RT-PCR) in the blood or in tissues
collected from a fatal case and virus isolation.
• Immunohistochemical staining can also show evidence
of viral antigen in formalin-fixed tissues.
• Later in the course of the disease, in people surviving,
antibodies can be found in the blood.
• But antigen, viral RNA and virus are no more present
and detectable.

• Treatment for CCHF is primarily supportive.
• Care should include careful attention to fluid balance
and correction of electrolyte abnormalities,
oxygenation and hemodynamic support, and
appropriate treatment of secondary infections.
• The virus is sensitive in vitro to the antiviral drug
ribavirin. It has been used in the treatment of CCHF
patients reportedly with some benefit.
Treatment

Prevention
• Agricultural workers and others working with animals
should use insect repellent on exposed skin and clothing.
• Insect repellants containing DEET (N, N-diethyl-m-
toluamide) are the most effective in warding off ticks.
• Wearing gloves and other protective clothing is
recommended.
• Individuals should also avoid contact with the blood and
body fluids of livestock or humans who show symptoms of
infection.
• It is important for healthcare workers to use proper
infection control precautions to prevent occupational
exposure.

• An inactivated, mouse-brain derived vaccine
against CCHF has been developed and is used
on a small scale in Eastern Europe.
• However, there is no safe and effective vaccine
currently available for human use.
• Further research is needed to develop these
potential vaccines as well as determine the
efficacy of different treatment options
including ribavirin and other antiviral drugs.
Prevention

Viral hemorrhagic fevers.pptx

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