The document discusses major vector-borne diseases in Saudi Arabia (KSA), focusing on Viral Hemorrhagic Fevers. It defines vectors and vector-borne diseases, and lists common disease-transmitting vectors such as mosquitoes and ticks. It then discusses Viral Hemorrhagic Fevers in detail, including epidemiology in KSA. Specifically, it covers dengue fever, Rift Valley fever, Alkhurma hemorrhagic fever, and Crimean-Congo hemorrhagic fever, providing background, transmission methods, symptoms and outbreak histories in KSA for each. It concludes with prevention methods against vector-borne diseases like insecticide use and personal protective measures.
2. Objectives
Define vectors and vector-borne diseases.
List the common vectors that can transmit
infectious diseases to human.
Define and discuss the importance of Viral
Hemorrhagic Fevers(VHFs).
Discuss the epidemiology of viral H fevers in KSA.
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3. Vector-borne Diseases-
(Introduction)
Vector-borne diseases are considered the most
serious diseases.
The seriousness of vectors because of their ability
to transmit the disease at a large scale in shorter
time, than other infectious diseases that
necessitate human-to-human contact.
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4. Vector-borne Diseases-
(Introduction)
Vectors can transmit diseases among different
living beings (mice, rats, monkeys, birds, dogs,
etc.) and humans.
Treatment of vector-borne diseases is difficult,
and the prevention essentially necessitates the
elimination of the vector.
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5. Vector-borne Diseases
What are vectors?
Vectors are living organisms that can transmit
infectious diseases between humans, or from animals to
humans.
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6. Vector-Borne Biseases
Vector-borne diseases:-
Are the diseases caused by disease-vectors.
Often found in tropical regions, where insects prevail,
and access to drinking water and sanitation is not safe.
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7. Disease-vectors
The common vectors that can transmit infectious
diseases to human are:-
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Vector Disease Transmitted(E.g.)
1- Mosquito Malaria, viral hemorrhagic fever(yellow fever and dengue
HF).
2- housefly Typhoid ,diarrheal diseases ,cholera ,poliomyelitis
,conjunctivitis ,… etc.
3- louse(lice) Epidemic typhus ,Relapsing fever
4- sand fly Kala-azar
5- Hard tick Tick typhus ,viral encephalitis ,viral hemorrhagic fever.
6- Itch-mite Scabies
7- tsetse fly Sleeping sickness
8. Mosquito
Constitute the most important vector from all vectors
that transmit disease to human.
They are found all over the world.
The four important groups of mosquitoes which are
related to disease transmission are:-
1.1. Anopheles.Anopheles.
2.2. Culex.Culex.
3.3. Aedes.Aedes.
4.4. Mansonia.Mansonia.
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9. Mosquito-borne diseases
Type of mosquito Disease
1- Anopheles. Malaria
2- Culex West Nile fever
3- Aedes Yellow fever
Dengue , Dengue hemorrhagic fever
Rift valley fever.
4- Mansonia Malayan filariasis.
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10. Viral Hemorrhagic Fevers(VHFs)
VHFs refers to a group of diseases, Caused by several
families of viruses that affect humans and animals.
characterized by:-
oAcute febrile syndrome.
oHemorrhagic manifestations.
oHigh mortality rates.
oEndemic in certain geographical regions.
oSometimes cause major outbreaks.
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11. Viral Hemorrhagic Fevers(VHFs)
The VHFs include infections caused by viruses of the
families :
Flaviviridae (dengue fever, yellow fever, Omsk
hemorrhagic fever, Kyasanur Forest disease, Alkhurma
hemorrhagic fever [AHF]).
Bunyaviridae (Crimean-Congo hemorrhagic fever
[CCHF], Rift Valley fever [RVF], and Hantavirus
diseases).
Arenaviridae (Argentine, Bolivian, Brazilian, and
Venezuelan hemorrhagic fevers and Lassa fever),
Filoviridae (Ebola and Marburg hemorrhagic fevers).
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12. Viral Hemorrhagic Fevers in KSA
The history of hemorrhagic fevers in the Arabian
Peninsula refers to 19th century . The first
recorded outbreak of a dengue-like disease, which
occurred from 1870 to 1873.
Most outbreaks were reported in the :Tihamah
region—The Red Sea coastal plain in the west and
southwest of Saudi Arabia and Yemen.
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13. Viral Hemorrhagic Fevers in KSA
The most common in Saudi Arabia are:-
Dengue fever.
Rift Valley fever.
Alkhurma hemorrhagic fever.
And Crimean-Congo hemorrhagic fever
(CCHF).
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15. Dengue fever and dengue
hemorrhagic fever
Are cosmopolitan vector-borne diseases.
Currently present in more than 100
countries.
And poses a public health threat to more
than 2.5 billion people worldwide.
With around 80 million people being
reported infected annually at an attack rate
of 4%.
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16. Dengue fever and dengue
hemorrhagic fever
Dengue virus is the most common arbovirus infection that
belongs to the family Flaviviridae/genus Flavivirus .
Can be transmitted by the bite of infective female
mosquitoes of the species Aedes aegypti ; and, to a lesser
extent, A. albopictus.
There are four serotypes dengue virus (DENV1–4).
But infection with one of them does not provide cross-
protective immunity against the other serotypes.
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17. Dengue fever and dengue
hemorrhagic fever
After an incubation period of two to five
days, dengue virus may cause:
Mild flu-like illness.
Or quickly progresses to serious dengue
hemorrhagic fever–dengue shock syndrome.
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18. Dengue fever and dengue
hemorrhagic fever in KSA
In the some parts of Saudi Arabia, Dengue fever
has:
Major effect on human populations' wellbeing.
And the country's economy.
Specifically in Jeddah city, which is one of the
main entry points to Saudi Arabia.
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19. History of Dengue in KSA
In 1990 an outbreak was reported for the first time in
Jeddah.
From 1994 to 2002,the refer laboratory in Jeddah reported
319 cases.
Next , two peaks were reported in 2005/2006,and another
two in 2008.
Dengue is now endemic in the western and southern
regions of KSA.
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20. Alkhurma hemorrhagic fever
Alkhurma hemorrhagic fever is caused by Alkhurma
hemorrhagic fever virus (AHFV) which is :-
A tick-borne encephalitis Flavivirus .
Can be transmitted by the bite of soft and
hard ticks (found in camels and sheep) .
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21. Alkhurma hemorrhagic fever
Alkhurma hemorrhagic fever virus (AHFV) :-
It was first isolated in Saudi Arabia and described
as a unique viral agent of Arabian Peninsula .
Significantly, AHFV shares a high similarity with
Kyasanur Forest disease virus, which was isolated in
India
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22. Alkhurma hemorrhagic fever
AHF is a zoonotic disease and clinical cases
have been attributed to exposure to
livestock (camels and sheep).
AHFV is not isolated yet from such
animals.
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23. Alkhurma hemorrhagic fever
After an incubation period of two to four days, the
disease presents initially with nonspecific influenza
like symptoms, including fever, anorexia, malaise,
diarrhea, and vomiting.
A second phase includes neurologic and hemorrhagic
symptoms in severe form.
Multi-organ failure leads to fatal outcomes.
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24. Alkhurma hemorrhagic fever
in KSA
It was isolated for the first time in 1995 in Jeddah from six
patients in Alkhurma district .
Since its first description, several hundred cases have been
reported in different western Saudi governorates.
AHFV was identified in Mecca from 2001 to 2003.
Several sporadic cases were recorded in Najran from 2003
to 2009.
Cases peaking in spring and summer.
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25. Bobbie Rae Erickson (center, in black) of CDC's Special Pathogens
Branch meets with Saudi and other scientists near a goat pen to learn
about Alkhurma virus transmission in livestock.
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26. Pierre Rollin (center) and Adam MacNeil (right) of CDC's Special
Pathogens Branch inspect a camel for ticks carrying the Alkhurma
virus.
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27. Crimean-Congo hemorrhagic fever
CCHF is caused by infection with a tick-borne
virus Nairovirus.
It is the most widespread tick-borne viral infection of
humans.
And the second most widespread of all medically
important arboviruses after dengue viruses.
CCHFV causes a subclinical disease in most livestock.
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28. Crimean-Congo hemorrhagic fever
CCHF virus was first recognized in Crimea in southeastern
in the mid-1940s and named Crimean hemorrhagic fever .
Then, it was isolated in Congo in 1969.
Thus resulting in the name of the disease.
Currently, CCHF is endemic in many countries in Africa,
Europe, and Asia.
The CCHF is related to Eid-al-Adha feast due to lack of
controlling livestock movements in and between countries
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29. Crimean-Congo hemorrhagic fever
in KSA
Outbreaks of CCHF have been reported in western
Saudi Arabia (1989–1990) .
It was suspected that the CCHF virus was introduced
to Saudi Arabia by infected ticks on imported
livestock (camels, cattle, sheep, goats, and buffaloes),
arriving to the Jeddah seaport.
The main risk factor was the exposure to the blood or
tissue of livestock in abattoirs, but not tick bites .
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30. Rift Valley fever
RVF is a vector-borne zoonotic disease .
Caused by a Phlebovirus .
RVF virus is:
Transmitted by Culex and A. aegypti mosquitoes.
resulting in large epizootics in livestock, which causes
abortion in pregnant ruminants and rapid death in
neonates.
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31. Rift Valley fever
Humans are incidentally infected when:-
They are bitten by infected mosquitoes.
Contact with aborted or infected animal tissues.
Or drink unpasteurized milk.
RVF virus is also a potential bioterrorism agent.
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32. Rift Valley fever
Humans suffering from RVF suffer influenza-like
symptoms .
After the initial febrile stage, in some cases, can
develop into ;
hemorrhagic fever.
encephalitis.
and death.
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33. Rift Valley fever in KSA
RVF was historically restricted to the Africa.
In 2000, RVF virus caused two simultaneous outbreaks in
Yemen and Saudi Arabia.
On September 15, 2000, the US Centers for Disease
Control and Prevention (CDC) isolated RVF virus from
Saudi Arabia.
Saudi Arabia reported 882 human cases and 124 deaths.
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34. Prevention of vector borne
diseases
Precautions for Protection against Disease-vectors:
Fight the vectors that transmit such diseases, as well as the
places where their larvae exist, by using proper insecticides.
Removing things that could probably provide a place for
water rafting.
Putting on long-sleeved wears, and covering legs at places
where insects exist, and using insect repellants.
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35. Prevention of vector borne
diseases
Precautions for Protection against Disease-vectors:
Using nets at doors and windows to prevent the entrance
of insects.
Using mosquito nets when sleeping outdoors.
Paying attention to the cleanliness of animals and animal
pens.
Maintaining personal hygiene .
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36. Prevention of vector borne
diseases
Precautions for Protection against Disease-vectors:
Avoiding travelling to the countries / places
stricken by vector-borne diseases
And making sure to take the necessary preventive
drugs and vaccines when travelling .
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37. References
Preventive and social medicine- k . PARK.
Epidemiology Leon Gordis .
https://www.cdc.gov.
https://www.moh.gov.sa.
https:// www.who.int.
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