Dengue: A global threat

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Dengue A Global Threat Audience United States
International Travelers Arkia Blackman, MPH
student Walden University PUBH 6165-5
Environmental Health Instructor Dr. Donald
Goodwin Spring, 2010
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Agenda

• Definition
• Modes of Transmission
• Serotypes
• Classification
• Contributing factors
• Statistics
• Prevention
• Treatment
• Tips for travelers
• Blood transfusion

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Definition

• What is Dengue?
• Dengue is a virus consisting of a single-stranded
  Ribonucleic Acid (RNA) (Thomas, John Kanish,
  2010).
• The virus genetic makeup consist of a lipid
  envelope protein that enables it to transport and
  bind in possible hosts (Teo, Ng Lam, 2009).

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Modes of Transmission

• Vector borne transmission
• Mosquito
• Non vector borne transmission
• Mother to child (Wiwanitki, 2010).
• Blood transfusion (Wiwanitki, 2010).
• Organ transplantation (Wiwanitki, 2010).

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Mode of Transmission

• Aedes Aegypti (Teo et al., 2009)
• Aedes albopictus (Teo et al., 2009)
• Aedes polynesiensis (Teo et al., 2009)

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Modes of Transmission

• Dengue is transmitted primarily by the mosquito
  family Aedes Aegypti (Teo et al., 2009).
• Dengue can also be transmitted by mosquito family
  Aedes albopictus and Aedes polynesiensis (Teo et
  al., 2009).
• A female mosquito bite leads to an infection of
  Dengue then is transmitted into other victims in
  a constant cycle.
• The incubation period of the infection varies
  7-14 days (Teo et al., 2009).
• The mosquito biting period occurs primarily in
  the dawn and at dusk (Teo et al., 2009).

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Modes of Transmission

• Mother to child transmission
• Can occur during a womans late term of their
  pregnancy through the placenta (Wiwanitki, 2010).
• Transmission through transfusion of blood and
  blood products (Wiwantiki, 2010).
• Transplantation of Dengue infected organs
  (Wiwantiki, 2010).

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Serotypes

• There are four serotypes of dengue (Teo et al.,
  2009).
• Den-1
• Den-2
• Den-3
• Den-4
• Infection of one serotype does not ensure
  immunity against the other serotypes (Teo et al.,
  2009).
• The serotypes are independent of each other (Teo
  et al., 2009).

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Classification

• Dengue fever
• Classified as individuals with symptoms such as
  headache, rash, leukopenia or myalgia along with
  the serological confirmation or in an area with
  similar cases (Thomas et al., 2010).
• Dengue hemorrhagic fever
• Classified by a previous or current fever lasting
  2-7 days, bleeding such as hematemesis, a high
  thrombocytopenia count, and evidence of plasma
  leakage (Thomas et al., 2010).
• Dengue shock syndrome
• Classified as having all the symptoms of dengue
  hemorrhagic fever and failure to the circulatory
  system (Thomas et al., 2010).

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Contributing Factors

• Population growth (Teo et al., 2009)
• Ineffective mosquito control (Teo et al., 2009)
• Global travel (Teo et al., 2009)
• Poor water management (Teo et al., 2009)

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Statistics

• 2.5 billion individuals are at risk globally
  (CDC, 2010).
• 100 million individuals become affected with
  dengue fever annually (CDC, 2010)
• Children make up the majority of the
• 500,000 cases of the fatal dengue hemorrhagic
  fever (CDC, 2010).

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Statistics

• Dengue is the second highest disease among
  travelers hospitalized after travel to tropical
  areas (Tomashek, 2009)
• Individuals that travel to dengue-endemic
  countries suffer an infection rate of 2.9 to 8
  (Tomashek, 2009)
• Dengue is the number one disease for individuals
  that travel to South Central Asia, Southeast
  Asia, Caribbean and South America (Tomashek,
  2009).

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Prevention

• Environmental control involves reducing or
  eliminating breeding grounds for mosquitoes by
  properly managing solid waste in a community or
  country (Gurugama, Garg, Perera, Wijewickrama
  Seneviratne, 2010).
• Chemical control involves the use of insecticides
  to target the larvae state of mosquito lifecycle
  or thermal fogging which is a form of spraying in
  the household (Gurugama et al., 2010).

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NO VACCINE AVAILABLE
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Treatment

• Dengue without warning signs
• Treatment include proper bed rest, replenishment
  of fluids and proper dosage of the drug
  Paracetamol (World Health Organization WHO,
  2009).
• Dengue with warning signs
• Treatment include fluid therapy as prescribed by
  medical personnel (WHO, 2009).
• Severe Dengue
• Treatment consist of fluid resuscitation with
  isotonic crystalloid solutions (WHO, 2009).

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Prevention

• Vaccines are being created and are in clinical
  studies so that they can be tested and researched
  for safety and effectiveness (Guzman, Vazquez
  Kouri, 2009)
• Some issues with creating vaccines include the
  differences between the four serotypes which may
  require different types of vaccine instead of one
  and the lack of an animal research subject
  (Guzman et al. 2009)

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Tips for Travelers

• Sleeping accommodations
• Travelers should ensure they are staying in
  accommodations that have air conditioning
  available and windows are appropriately screened
  (Tomashek, 2009).
• Clothing
• Travelers should wear clothing that protects
  exposed areas such as legs and arms to ensure
  mosquitoes do not have easy access to bite and
  transmit the dengue virus (Tomashek, 2009).
• Insect Repellant
• Repellant is very important and necessary when
  traveling to areas that are endemic to dengue.
  The repellant should be used on clothes and areas
  of the skin (Tomashek, 2009).

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Blood Transfusions

• Donor qualification
• Due to the rise of dengue infection in endemic
  countries and among travelers the individuals can
  be deferred from donating blood to prevent the
  risk of transfusion related transmission of
  dengue (Teo et al., 2009).
• In various countries blood donors are being
  deferred for 6 months and 2-3 weeks and this
  diminishes the number of blood donations
  available for emergency and routine use (Teo et
  al., 2009).
• NAT testing
• The cost of NAT testing for dengue will be
  expensive and necessary to detect dengue in blood
  donations to ensure there is a safe blood supply
  (Teo et al., 2009).

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Summary

• Dengue is a virus transmitted by vector and non
  vector methods
• There are 3 types of dengue disease, dengue
  fever, dengue hemorrhagic fever and dengue shock
  syndrome
• Travelers need to protect themselves when
  traveling to prevent infection of dengue
• No vaccine is available for use currently
• Blood donations are at risk

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Questions
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References

• Center for Disease Control. (2010). Dengue-A
• Worldwide Threat. The Dengue Update. Volume 1.
• Retrieved on April 24, 2010, from
• http//www.cdc.gov/dengue/dengue_upd/index.html
• Gurugama, P., Garg, P., Perera, J.,
  Wijewickrama, A.,
• Seneviratne S. L. (2010). Dengue Viral
  Infections. Indian
• Journal of Dermatology, 55(1), 68-78. DOI
  10.4102/0019
• 5154.60357.
• Guzman M. G., Vazquez, S. Kouri, G. (2009).
  Dengue
• where are we today? Malaysian Journal of Medical
  Sciences,
• 16(3), 5-12. Retrieved from Academic Search
  Complete Database
• Teo D., Ng L. C., Lam, S. (2009). Is dengue a
  threat to the
• blood supply? Transfusion Medicine, 19, 66-77.
  doi
• 10.111/j.1365-3148.2009.00916.x

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References

• Thomas E. A., John, M., Kanish B. (2010).
• Mucocutaneous Manifestations of Dengue Fever.
• Indian Journal of Dermatology, 55(1), 79-85. DOI
• 10.4103/0019-5154.60359.
• Tomashek, K. M. (2009). Dengue Fever (DF) and
• Dengue Hemorrhagic Fever (DHF). Retrieved April
• 25, 2010, from
• http//wwwnc.cdc.gov/travel/yellowbook/2010/chapte
  r-5/dengue-fever-dengue-hemorrhagic-fever.aspx
• Wiwanitkit, V. (2010). Non vector-borne
  transmission
• modes of dengue. Journal of Infection In
  Developing
• Countries, 4(1), 051-054. Retrieved from Academic
  Search
• Complete Database.

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References

• World Health Organization. (2009). Dengue
• Guidelines for Diagnosis,Treatment, Prevention
  and Control.
• Retrieved April 24, 2010, from
• http//whqlibdoc.who.int/publications/2009/97892
  1547871_eng.pdf

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Sources to Read

• For information on insect repellants such as how
  to use them, when to use and why to use them
  check out the following site
• Centers for Disease Control and Prevention.
  Insect Repellent
• Use and Safety updated 2008 May 14 cited 2008
  Nov 29. Available from
• www.cdc.gov/ncidod/dvbid/westnile/qa/insect_repel
  lent.htm.
• For additional information on insect repellants
  and which ones are registered and unregistered
  and alternative preventative measures please
  visit this site on the U.S. Environmental
  Protection Agency
• U.S. Environmental Protection Agency. How to Use
  Insect
• Repellents Safely updated 2007 July 5 cited
  2008 Nov 29. Available from
• www.epa.gov/pesticides/health/mosquitoes/insectr
  p.htm.

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Sources to Read

• For information on the research being conducted
  to create a vaccine and the progress and
  challenges of this effort please read the
  following article
• Swaminathan, S. Khanna, N. (2010). Dengue
  vaccine
• current progress and challenges. Current
  Science. 98(3)369-378