4. Dengue Flashcards
Positive-sense
single-stranded RNA
Dengue virus
Dengue
Family:
Genus:
Dengue
Family: Flaviviridae
Genus: Flavivirus
(4) antigenically-related dengue serotypes:
DENV 1, 2, 3, 4
First recorded Dengue in Southeast Asia occurred in ___ in 1954
Manila
How many are at risk of Dengue in the world’s population?
over 50%
Number of Dengue infections occurring each year?
100-400 M
How many deaths (Dengue)?
21,000
Dengue cases in the PH?
48, 109
Deaths in the PH (Dengue)
176
Top 3 places with highest number of cases of Dengue?
- NCR
- CALABARZON (Region 4A)
- Central Luzon (Region 3)
Dengue outbreaks
Season:
Months:
Dengue outbreaks
Season: wet season
Months: June - February
Dengue incident rate was highest among ___ age of children.
with over 80% of dengue related deaths occurring among individuals of less than 20 years of age
5-14 y.o.
(4) Aedes spp. that transmits Dengue
1) A. aegyptii
2) A. albopictus
3) Ae. polynesiensis
4) Ae. niveus (Asia)
The adult mosquitoes feed on humans during ______ hours
daylight
are two peaks of biting activity of Dengue
- early morning for 2-3 hours after daybreak
-
afternoon for several hours
before dark
A. aegyptii females often feed on several persons during a ____ blood meal
increasing the transmission rate
single
DENV virus replicates in the mosquito’s _____________
midgut
Extrinsic incubation period: ______ days at 25 30 C.
7 - 14 days (before it becomes infectious)
Human-mosquito transmission can occur up to
1) 2 days before onset of symptoms
2) up to 2 days after fever has resolved
Is there a vertical transmission in Dengue?
rare
This type of cycles account for a small percentage of the global extent of the human case record, but could be increasing in relevance in
- Asia
- Africa
- South America
Sylvatic cycle (in Africa)
________________ appear
to be the only amplification and
reservoir hosts of Dengue
Non-Human Primates (NHP)
Dengue mosquito in South East Asia
Ae. niveus spp.
Dengue virus can infect at least 84 species of ____ animal types
including 28 species of non-human primates
23
Kato et al. (2011) demonstrated a “spillback event” in __________ in the Philippines, proving that NHPs can be involved in the human/urban DENV cycle
cynomolgous macaques
Infection with ____ can result in asymptomatic infection to severe, potentially life threatening
disease.
any of the four DENV
Incubation period: ____ after the bite of the infected mosquito
4 - 10 days
Symptomatic clinico-pathological features in HUMANS
- Non-specific febrile illness
- Classical dengue fever
- Dengue haemorrhagic fever
- Dengue haemorrhagic fever with dengue shock syndrome, encephalopathy and liver failure
After an infection with a DENV:
___________________________A person infected with DENV-1 cannot become ill as a result of DENV-1 infection again.
Lifelong type specific-immunity
After an infection with a DENV:
____ is against other DENV types for about 2
to 6 months.
Short-term cross-immunity
gold standard laboratory tests to confirm dengue virus
PCR of whole blood
Other tests for Dengue: (2)
1) NAAT-LAMP
2) PRNT
Gold standard to characterize and quantify circulating level of anti-DENV neutralizing antibody (NAb)
Plaque Reduction Neutralization Test (PRNT)
- Requested between 1-5 days of illness
- Use to detect dengue virus antigen during early phase of acute dengue infection
- Test is for free in all health centers and selected public hospitals nationwide
Dengue NS1 RDT
- Done beyond 5 days of illness
- May cross react with other arboviral diseases such as Chikungunya and Zika
Dengue IgM / IgG
Is there a vaccine for Dengue?
YES
CYD-TDV (Dengvaxia) - a live recombinant tetravalent dengue vaccine for 9-45 y.o.
3-dose series of Dengvaxia
0 / 6 / 12 month schedule
