1. Controlling
Dengue
Rafi ur Rahman
M. Phil (Biotechnology and
Genetic Engineer)

2. Introduction:
Dengue
Causative Agent, The Virus
Transmission
The Mosquito
Control

3. The Dengue Fever
 Is an acute fever producing infectious
disease
 Mostly found in the tropics
 Pronounce DEN-ghee
 Complications can be fatal
 It is also known as Dengue fever , break-
bone fever.
 Complicated forms are DHF and DSS

4. Causative Agent: The Virus
 RNA Virus
 Genus Flavivirus.
 Family Flaviviridae.
 11000bp which encodes a single large
poly protein.
 Other relatives: West-Nile virus, Yellow
fever virus, hepatitis C virus.
 Four Serotypes: DEN1-4. 60-80% sequence
homology and also Surface Protein
Homology

5. Transmission:
 Aedes Aegypti: Cosmopolitan.
 Ae. Albopictus: South-East Asia.
 Biting around the ankles and knees close to
the ground in the daytime
 Distinct Physical Features.
 Life cycle.

6. The Mosquito:
 Dengue cases usually increase during the
rainy season
 The spread of the mosquito is attributed
to poor environmental sanitation
 When it rains the water gets stored in any
place such as discarded tires, broken
bottles, and even shoes
 Other examples are soda
cans, birdbaths, rain gutters, toys, pool
covers, tree stumps, and garbage cans.

7. More About the Causative
Agent:
 Male feeds on plant nectar
 Female feeds on blood (Human, Animals,
Birds, Monkeys).
 Life Span: 14-21 days.
 Lays 300 eggs during her life span.
 The mosquito can travel up to 10 km.

9. Control:
 No specific vaccine or drug invented.
 Can be controlled by limiting
 1) Eliminating the Mosquito vector and/or
 2) Interrupting Human-vector Contact.
THAT’S WHY;
 Clothing, that minimize skin exposure must be
used.
 Mosquito repellents.
 Mosquito nets.
 Don’t let clear water un-covered for more
than 1 day.
 Put the cover on water container along with
cloth.

10. Contdd..
 If the larvae are seen any where, put
some detergent(surf), wait for some time
and then discard.
 Do not leave any source into the water
tanks(over-flow, air source), if left
however, cover with some sort of net or
long pipe.
 Focus on neglected areas like water pots
in bird cages etc..
 Turn over all unused water containers.

11. Control:
 Control of Immature stages:
 Vector control: 1. Larviciding with insecticides.
2. Elimination of breeding sites
 Only Temephos, Permethrin, Bti, and Pyriproxyfen
are approved by WHO for use in drinking-water.
 Bti Toxins: Bacillus thuringiensis var.
israelensis (Bti), Bacillus Sphaericus (Bs).
 High larvicidal activity in mosquitoes.
 Should be used in Combinations:
[BTi + Insecticide], [BTi + Copepods]: Excellent
results.
 Commercial Preparations: Liquid/Granular Preps
are available.

12. References:
 Akram, W., (n.d.). Aedes as a vector of Dengue: a possible threat to
our lives. Khwarzimig Science Society. University of Agriculture,
Faisalabad. Retrieved April 19, 2010 from
http://www.khwarzimic.org/takveen/dengue_kss.pdf
 Bauman, R., (2006). Microbiology disease by systems. San Francisco
, CA: Pearson Benjamin Cumming Publisher
 Center for Disease Control and Prevention, (2009)Dengue
epidemiology. Retrieved April 22, 2010 from
http://www.cdc.gov/Dengue/epidemiology/index.htm
 Center for Disease Control and Prevention, (2009). Other infectious disease
related to travel, dengue fever (DF) and dengue hemorrhagic fever (DHF).
Retrieved April 19, 2010 from
http://wwwnc.cdc.gov/travel/yellowbook/2010/chapter-5/dengue-fever-
dengue-hemorrhagic-fever.aspx
 Center for Disease Control and Prevention, (2009). About CDC’s dengue
branch. Retrieved April24, 2010 from
http://www.cdc.gov/Dengue/about/index.html
 Gubler, D.J., Clark, G.G., (1995)Dengue/dengue hemorrhagic fever: The
emergence of a global health problem. Retrieved April 19, 2010 from
ftp://ftp.cdc.gov/pub/EID/vol1no2/adobe/gubler.vol1no2.pdf
 Gubler, D., (1998). Dengue and dengue hemorrhagic fever . Clinical
Microbiology Reviews, July 1998, p.480-496. Retrieved April 24, 2010 from
http:/www.cmr.asm.org/cgi/repreint/11/3/480
 World Health Organization, (2009). Dengue and Dengue haemorrhagic fever.
Retrieved April 19, 2010 from
http://www.who.int/mediacentre/factsheets/fs117/en/

13. Recommended Sources :