1. Dengue Fever Information for Interning
JoDee Summers
Walden University
Hello everyone, my name is JoDee Summers, and I’m a graduate student at Walden University. This purpose of this presentation is to give you information on Dengue Fever that will help prepare you for your internship in a Dengue endemic area.

2. What is Dengue? Arbovirus Flavivirus: Mosquito borne: (Aedes aegypti)
Primarily a daytime feeder that lives around human habitation
What is Dengue? Dengue is an Arbovirus and is part of the Flavivirus family. Some of Dengue’s “siblings” are yellow fever, St. Louis Encephalitis, West Nile Fever, and Japanese Encephalitis. Dengue is transmitted by mosquitoes, specifically the Aedes aegypti mosquito. Unlike the other mosquitoes who carry the “sibling viruses,” which are dusk-to-dawn feeders, the A. aegypti mosquito is primarily a daytime feeder that loves to live around people.

3. Virginia Bioinformatics Institute, 2006
The life cycle of Dengue begins with an infected individual. The mosquito bites the infected person and then the virus replicates in the mosquito for 8-12 days. After that, the mosquito bites a human, and infects them. The virus then replicates in the human for around 4-7 days (can be up to 14 days). And the circle continues…..
Virginia Bioinformatics Institute, 2006

4. The Virus 4 serotypes: DEN-1, DEN-2, DEN-3 and DEN-4
Each serotype provides specific lifetime immunity and some possible short term cross immunity.
Each serotype carries possibility of serious or life threatening disease, but some appear to be more virulent then others.
There are 4 serotypes of Dengue. They are VERY original names too. DEN-1, DEN-2, DEN-3, DEN-4. Once you contract one of the serotypes, you are immune to that strain for life. You can also be immune for a short period of time to some of the other strains. Each serotype can be life threatening, but it appears that some strains are more virulent (or more severe) than others.
Centers for Disease Control and Prevention, 2009

5. Clinical Syndromes Undifferentiated fever: Classic dengue fever
Most common manifestation
Majority asymptomatic or mildly symptomatic
Classic dengue fever
Dengue hemorrhagic fever (DHF)
Dengue shock syndrome (DSS)
Dengue presents itself in a few ways. The most common is a fever along with just feeling lousy (malaise) and is often referred to ‘undifferentiated fever.’ A rash may be present. A little more severe, is ‘Classic Dengue Fever’ which would include fever, malaise, headache, nausea & vomiting, and eye pain. Many patients report suffering from depression following the acute illness.
More severe then Classic, is “Dengue Hemorrhagic Fever” which includes all the previously mentioned symptoms, along with hemorrhagic manifestations (which will be described later). Dengue shock syndrome is all the previously mentioned symptoms, but also includes organ failure and eventually death.

6. Dengue Hemorrhagic Fever
4 Criteria:
Fever, or recent history of acute
Hemorrhagic manifestations
Low platelet count (100,000/mm3 or less)
Objective evidence of “leaky capillaries”
In order to be considered a case of Dengue Hemorrhagic Fever, you need to fit 4 criteria.
You need to have a fever, or recent history of the acute Dengue Fever.
2. You need to have hemorrhagic manifestations: spontaneous bleeding, positive tourniquet test (Inflate blood pressure cuff to a point midway between systolic and diastolic pressure for 5 minutes. Positive test: 20 or more petechiae per 1 inch² (6.25 cm²) )
Low platelet count
Objective evidence of “leaky capillaries,” which include an elevated hematocrit (20% or more over baseline), low albumin, and pleural or other effusions.
Source: Pan American Health Organization: Dengue and Dengue Hemorrhagic Fever: Guidelines for Prevention and Control. PAHO: Washington, D.C., 1994: 12.
Pan American Health Organization, 1994

7. 4 Grades of DHF Four Grades of DHF Grade 1 Grade 2 Grade 3 Grade 4
Fever and nonspecific constitutional symptoms
Positive tourniquet test is only hemorrhagic manifestation
Grade 2
Grade 1 manifestations + spontaneous bleeding
Grade 3
Signs of circulatory failure (rapid/weak pulse, narrow pulse pressure, hypotension, cold/clammy skin)
Grade 4
Profound shock (undetectable pulse and BP)
There are four grades of Dengue Hemorrhagic Fever. The higher the number, the more severe. Each are listed on this slide.
Centers for Disease Control and Prevention, 2009

8. Dengue History
: First reported epidemics in Asia, Africa, and North America.
Post WWII: Introduced to Southeast Asia. 
1950s: : Epidemic Dengue Hemorrhagic Fever in Southeast Asia.
Currently: Most countries in the world.
Where did Dengue come from? The first reported epidemics of Dengue Fever were first reported in in Asia, Africa and North America. After WWII, a pandemic of Dengue began in Southeast Asia and has spread around the globe since then. Dengue Hemorrhagic Fever presented itself in the 1950’s in Southeast Asia, and by 1975 became a frequent cause of hospitalization among children in many countries in that region. With increasing travel, Dengue Fever has made its way to most countries in the world.

9. World Health Organization, 2008
This map, from the World Health Organization, shows how Dengue has spread rapidly after 1960 to many countries in the world.
World Health Organization, 2008

10. Centers for Disease Control and Prevention, 2009
This map shows the spread of Dengue Hemorrhagic Fever prior to 1981 and compares it to the years in South America.
Centers for Disease Control and Prevention, 2009

11. World Health Organization, 2008
This graph is another representation of the increase in cases of Dengue (both regular fever and hemorrhagic) over time, and the number of countries the virus is present in.
World Health Organization, 2008

12. Recent Activity Puerto Rico outbreak South Texas = 2005
Texas 1997 = 3 locally acquired
Texas 1995 = 7 locally acquired
The U.S. has the mosquito, but rarely see cases
Puerto Rico is currently experiencing one of the largest outbreaks of Dengue fever ever recorded. There are travel advisories and information has been given to physicians across the world to look for Dengue in residents who have recently returned from Puerto Rico. On the continental United States, the most recent outbreak was in South Texas in Previous to that, there were three locally acquired cases in Texas in 1997, and seven locally acquired cases in Dengue rarely occurs in the United States, although we have the Aedes aegypti mosquito. This is largely due to changes in lifestyle – for example, screened houses, air conditioned buildings, and reliable potable water supplies in homes.

13. Diagnosis General Recommendations Epidemiologic considerations
Season of year
Travel history
Important for assessment of symptomatic patients in non-endemic areas
Determine whether the patient traveled to a dengue-endemic area
Determine when the travel occurred
If the patient developed fever more than 2 weeks after travel, eliminate dengue from the differential diagnosis
Now we know WHAT Dengue is, and WHERE it came from. Now we will answer the WHEN and HOW to diagnose. When diagnosing Dengue Fever, there are several recommendations to keep in mind. For example, epidemiologic considerations. Is it the appropriate season? Did the patient travel to an endemic area? When did the patient travel? When did they develop symptoms, and does it fit the appropriate incubation period?

14. Differential Diagnosis
Influenza
Measles
Rubella
Malaria
Typhoid fever
Leptospirosis
Meningococcemia
Rickettsial infections
Bacterial sepsis
Other viral hemorrhagic fevers
It’s important to remember Dengue Fever has similar symptoms to other diseases, and can be mistaken for something else. Here are some of the common differential diagnosis, or “Oops, I thought it was this disease.”

15. Laboratory Tests Clinical laboratory tests Dengue-specific tests
CBC—WBC, platelets, hematocrit
Albumin
Liver function tests
Urine—check for microscopic hematuria
Dengue-specific tests
Virus isolation
Serology (IgM ELISA)
When running laboratory tests, there are tests that will help determine if the patient fits the clinical picture for Dengue. These include complete blood counts, albumin levels, liver function tests, and urine analysis. Also, there are blood tests that can determine if the patient has developed any antibodies to Dengue.

16. Collection of Samples The tests for diagnosis are time dependent.
Patient presents within 5 days of onset of symptoms: draw blood immediately.
A convalescent-phase sample should also be drawn.
Patient presents 6 or more days after symptom onset: the blood sample should be drawn as soon as possible. This sample should then be tested for serum IgM antibody.
If the patient presents within the first 5 days after onset of symptoms, (acute phase), a blood sample should be drawn immediately. Virus can be isolated most easily in samples drawn in the first days after onset of symptoms, although it has been isolated as long as 12 days after onset. A convalescent-phase sample should also be drawn to test for IgM antibody. This sample should be drawn between 6 and 21 days after symptom onset. If the patient presents six or more days after symptom onset, the blood sample should be drawn as soon as possible. This sample should then be tested for serum IgM antibody.

17. Treatment
Fluids
Rest
Antipyretics (avoid aspirin and non-steroidal anti-inflammatory drugs)
Monitor blood pressure, hematocrit, platelet count, level of consciousness
Avoid invasive procedures when possible
Unknown
Patients in shock may require treatment in an intensive care unit
Since Dengue is a virus, there are no antibiotics to treat it. Fluids and rest are usually the best prescription. However, Dengue can potentially be hemorrhagic, as we have learned, so taking drugs that will promote blood thinning is not recommended. A physician may want to monitor blood pressure and blood counts, and if severe enough, may be admitted into a hospital. It is unknown if the use of steroids, intravenous immune globulin, or platelet transfusions to shorten the duration or decrease the severity of thrombocytopenia is effective

18. Personal Prevention No vaccine Prevent mosquito breeding
Eliminate standing water
Fix window screens
DEET or Picaridin
Unfortunately, there is no vaccine for Dengue, yet. There are several vaccines that are in clinical trials, but nothing that has been approved for human use. In the meantime, there are still several things that you can do personally, to protect yourself from Dengue. The most important thing to do is to eliminate any possible mosquito breeding grounds. Millions of mosquito larvae can grow in very little amount of water. Pots, dog bowls, decorative fountains, old tires, etc. can all collect water; this creates an ideal breeding ground for mosquitoes. Remove these water collectors, or change the water frequently, to avoid it becoming stale or stagnant. Another thing that you can do is repair damaged window screens to prevent mosquitoes from coming indoors. And last, wear mosquito repellant containing DEET or Picaridin. Both of these repellants are approved by the CDC for effective and safe repellant against mosquitoes.

19. Community Prevention Lessons for Future Dengue Prevention Programs
Sustainable environmental control vs. eradication
Community-based programs
Promote the priority among health officials and general public
There have been many lessons learned by countries who are creating Dengue prevention programs. One is that efforts should focus on sustainable environmental control, rather than eradication. Another very important one is that control programs should be community-based. Programs that emphasize telling communities what to do, without involving them or taking their views into account, are not likely to be effective. Another lesson learned is that a prevention program will not work if it relies solely on insecticides or if it requires a large budget. Also, promoting Dengue as a priority among health officials, as well as the general public will be essential. The more support, the better.

20. Examples of What YOU Can Do!
Involve the children!
Interactive exhibits
Public service announcements
Television
Radio
Brochures
You can make a difference! Some of the examples or suggestions you could incorporate into your internship could include working with the elementary schools to teach children about Dengue control. Often, children teach their parents what they learned at school, and they can potentially understand the importance of something more easily then “grown-ups.” You could also create interactive exhibits at children’s museums, parks, etc.
Create public service announcements. In countries where radio and television ads can be run, create a simple 20 second sound bite that will attract listeners/viewers, perhaps a catchy phrase that will stick in their minds.

21. Further Reading http://www.cdc.gov/dengue/educationTraining/index.html
The CDC webpage has excellent educational materials that you can incorporate into your internship.
The CDC webpage also has information on the increase of Dengue cases in Puerto Rico, as well as intervention strategies they are putting into place.
The World Health Organization has a publication entitled “Dengue Guidelines for Diagnosis, Treatment, Prevention and Control” that has a lot of good information

22. References:
World Health Organization (2008). Global alert and response. Impact of Dengue. Retrieved from
Centers for Disease Control and Prevention (2009). Dengue epidemiology. Retrieved from
Virginia Bioinformatics Institute, (2006). Dengue transmission cycle. Retrieved from ci.vbi.vt.edu/pathinfo/pathogens/Dengue1.html
Pan American Health Organization. (1994) Dengue and dengue hemorrhagic fever: Guidelines for Prevention and Control. PAHO: Washington, D.C., 1994: 12.

23. Questions??
I would be happy to answer any questions you have. Thank you.