1. Dengue: A Tropical Vector Borne Disease in the Cayman Islands
Deborah Jarrett (Ph.D)
Walden University 
PUBH  
Instructor: Dr. Howard Rubin
Summer, 2010
Bigongiori, 2009

2. Audience Primary: Health Care Professionals in Grand Cayman Secondary: Community Members Purpose of Presentation
I am Deborah Jarrett, and I am currently enrolled in the doctoral public health program at Walden University.
The goal of this presentation is to provide health care professionals and other community members in the Cayman Islands with current information regarding the epidemiological characteristics of dengue.
Education is important to initiate preventive measures or implement treatment that will subsequently prevent dengue epidemic despite the associated environmental risks in this Caribbean island.

3. Agenda Introduction Objectives Definition of Dengue
Epidemiological Characteristics of Dengue
Significance of Dengue
Prevention and Control Measures
Public Health & Environmental Implications
Recommendations
The duration of this presentation will be approximately one hour, and topics will be presented in the sequence as outlined in the agenda.

4. Introduction
Dengue is a viral vector borne disease transmitted by the female aedes mosquito , and is endemic in tropical regions such as the Caribbean which includes the Cayman Islands. There are several environmental factors in the Cayman Islands that could contribute to the development of a dengue epidemic. These include a warm climate, rainy seasons, the accumulation of stagnant water in swamps and mangroves, unsanitary conditions at the landfill, and global travel which contributes to an increase in the growth of the aedes mosquito population.
The CDC reported that dengue is “the most important mosquito borne viral disease in the world” and subsequently have resulted in millions of death, illnesses, social burden, psychological distress and financial constraints. Primary prevention measures include education campaigns to increase awareness about dengue, community participatory activities to sustain a healthy environment, and mosquito control programs to reduce the aedes mosquito population and prevent mosquito bites.
The best way to reduce mosquitoes is to eliminate the places (water holding containers or areas) where the mosquito lays her eggs, ensure proper solid waste disposal, improve water storage practices (cover water holding containers), and apply approved insecticides. Appropriate treatment for infected individuals, as well as community participation, behavior modification, and supportive environmental policies are also essential in the prevention and control of dengue as the aedes mosquitoes are highly resilient and adapt to environmental conditions.
Three cases of dengue were reported in the Cayman Islands in January This reflected an increase in the prevalence in comparison to one case of dengue hemorrhagic fever that was reported in 2008, and one case of dengue fever in 2009 (Connolly, 2010). These reports along with additional evidence of recent increases in the number of dengue cases in other Caribbean Islands have led to concerns regarding possible epidemics in the Cayman Islands.
Knowledge of dengue including the causative agent, mode of transmission, public health and social impact of dengue, as well as effective prevention and control measures are therefore essential, and are emphasized in this presentation as there is no specific treatment or approved vaccines to prevent dengue.

5. Objectives By the end of the presentation individuals will be able to:
Identify the causative agent and mode of transmission of dengue.
Determine the role of mosquitoes in the transmission of dengue.
Identify the clinical manifestations of dengue fever and dengue hemorrhagic fever.
The information that is provided will enable each individual to achieve the following objectives by the end of the presentation:
Identify the causative agent and mode of transmission of dengue.
Determine the role of mosquitoes in the transmission of dengue.
Identify the clinical manifestations of dengue fever and dengue hemorrhagic fever.

6. Objectives
Understand the global and national impact of dengue in relation to prevalence, morbidity rate, mortality rate, and societal cost.
Identify and implement appropriate control or preventive measures.
Advocate for public policies and programs that will reduce the risk of dengue transmission.
Initiate and sustain community participatory dengue prevention programs.
Understand the global and national impact of dengue in relations to prevalence, morbidity rate, mortality rate, and societal cost.
Identify and implement appropriate control or preventive measures.
Advocate for public policies and programs that will reduce the risk of dengue transmission.
Initiate and sustain community participatory dengue prevention programs.

7. Epidemiological Characteristics of Dengue
Definition
Dengue is a vector borne viral disease
Causative Agent
The Flaviviridae or Dengue Viruses
(“Medical Dictionary,” 2010).
We will commence this session on the epidemiological characteristics of Dengue by first defining dengue, and then identifying the causative agent.
Dengue is a vector borne disease caused by one of four distinct, but related arboviruses or arthropod borne viruses know as Flaviviridae which is transmitted by mosquitoes to humans, resulting in symptoms of ill-health (“Medical Dictionary,” 2010).
“Recovery from infection by one provides lifelong immunity against that virus but confers only partial and transient protection against subsequent infection by the other three viruses. There is good evidence that sequential infection increases the risk of developing DHF” (“World Health Organization”, 2009)

8. Mode of Transmission Vector – Borne
Female Aedes Aegypti and Albopictus mosquitoes act as intermediate vector
Non Vector- Borne
Organ Transplant
Blood Transfusion & Hemodialysis
Vertical Transmission
(“Centers for Disease Control and Prevention,” 2010).
Dengue virus is not transmitted by direct contact (person to person), but rather indirectly through a vector. The female Aedes aegypti and albopictus mosquitoes act as intermediate vector which carries the dengue virus after biting an infected person (host), and is then able to transmit the virus to other healthy individuals after approximately one week (incubation period). The newly infected person can either manifest symptoms of dengue fever or dengue hemorrhagic fever, or may be asymptomatic. The infected female mosquito remains infected for the rest of its life cycle, and continues to transmit the virus to other healthy humans, who now become the main carriers and host for the dengue virus.
Infrequently this virus may be transmitted during organ transplant, hemodialysis or blood transfusion which is also known as health care acquired dengue infections. The vertical transmission of dengue occurs during the antenatal period from an infected mother to the unborn fetus and may result in serious illness or death of the neonate (“Centers for Disease Control and Prevention,” 2010).

9. Vector Borne Transmission
Infected Human
( Main Carrier & Multiplier for DENV)
Uninfected Female Aedes Mosquito Bites Infected Human
Mosquito Becomes Infected (after days)
Mosquito Bites & Infects Human(after days)
This diagram reflects the cycle in the transmission of dengue between the vector( the aedes mosquito) and humans who are considered the host and main carriers for the dengue virus.
As discussed earlier, and reported by the Centers for Disease Control and Prevention (2010) the transmission of dengue virus occurs between human and the aedes mosquitoes . “Symptoms of infection usually begin days after the mosquito bite and typically last days”.  Transmission of the virus can occur if the mosquito bites an infected person during the incubation period or “5- day period when large amounts of virus are in the blood”. The now infected mosquito “requires an additional 8-12 days incubation before the virus can then be transmitted to another human”.
(“World Health Organization, “2009).

10. Disease Frequency – (Global Statistics)
Dengue Virus is:
Endemic in tropical and sub- tropical regions
“The most important mosquito borne viral disease in the world”
(“Centers for Disease Control and Prevention,” 2010).
Dengue virus is endemic in tropical regions such as the Caribbean, Central America, South Central Asia, South Pacific, and Africa. This is due to the warm climatic conditions, rainy seasons, and other environmental conditions that promote water accumulation and poor sanitation. The CDC reported that dengue is “the most important mosquito borne viral disease in the world” (“CDC,” 2010).
Dengue and dengue hemorrhagic fever mainly occur in the urban and suburban areas in these regions , except in Africa where dengue fever is present mainly in rural areas.
The World Health Organization (2010) stated that the following conditions contribute to dengue epidemic in developing countries:
Rapid population growth
Rural-urban migration
Inadequate basic urban infrastructure such as unreliable water supply leading householders to store water in containers close to homes
Increase in volume of solid waste, such as discarded plastic containers and other abandoned items which provide larval habitats in urban areas
International commercial trade particularly in used tyres which easily accumulate rainwater.
Increased air travel and breakdown of vector control measures have also contributed greatly to the global burden of dengue and DHF (WHO, 2010).

11. Disease Frequency Increased Incidence Increased Prevalence
Increased Relative Risk
Increased Childhood Mortality Rate
Increased Fatality Rates
Dengue has a 30 –fold increased incidence rate over the last 50 years, and more than 50 million infections reported annually of which 500,000 cases developed dengue hemorrhagic fever. Approximately 2.5 billion individuals in more than 100 endemic countries are at risk for dengue. Dengue subsequently results in 22,000 deaths annually especially among children (“Centers for Disease Control and Prevention,” 2010). The incidence rate for dengue hemorrhagic fever may increase to 90% during periods of epidemics, and fatality rates can increase above 20% in the absence of proper treatment (“WHO”, 2009).
The World Health Organization (2010) further stated that “during the 19th century, dengue was considered a sporadic disease that caused epidemics at long intervals…, and prior to 1970, only 9 countries had experienced cases of dengue hemorrhagic fever (DHF); since then the number has increased more than 4-fold and continues to rise”.

12. Disease Frequency – (Caribbean Region) Table 1: Total Number of Reported Cases of Dengue Fever and Dengue Hemorrhagic Fever in the Caribbean by Year
Year
DF/DHF
DHF/Deaths
2002
14,925
285/35
2001
19,023
233/8
2000
10,542
140/15
1999
9,412
137/25
1998
28,036
543/19
1997
12,935
424/37
1996
9,815
44/7
1995
11,483
213/15
Source: (Lloyd, 2003)
This chart provides data about the morbidity and mortality of dengue and dengue hemorrhagic fever in the Caribbean between 1995 and The highest number of dengue fever, dengue hemorrhagic fever, and related deaths were recorded in 1998 in contrast to the lowest recorded figures in 1996 and 1999.

13. Disease Frequency – (National Statistics)
One reported case of dengue hemorrhagic fever in 2008
One reported case of dengue fever in 2009
Three reported cases of dengue in January 2010
(Connolly, 2010)
An evaluation of the recent statistics for the Cayman Islands revealed that three cases of dengue were reported in the Cayman Islands in January 2010, in contrast to one case of dengue hemorrhagic fever in 2008, and one case of dengue fever in 2009 (Connolly, 2010).

14. Significance of Dengue
Human Impact
Dengue Fever
Dengue Hemorrhagic Fever
Significance of Dengue
The Centers for Disease Control and Prevention (2010) reported that:
“The principal symptoms of dengue fever are high fever, severe headache, severe pain behind the eyes, joint pain, muscle and bone pain, rash, and mild bleeding (e.g., nose or gums bleed, easy bruising). Generally, younger children and others infected for the first time usually experience milder signs and symptoms of the disease, when compared to older children and adults with repeat infections.
Dengue hemorrhagic fever is characterized by a fever that lasts from 2 to 7 days, with general signs and symptoms consistent with dengue fever. When the fever declines, symptoms including persistent vomiting, severe abdominal pain, and difficulty breathing, may develop. This marks the beginning of a 24- to 48-hour period when the smallest blood vessels (capillaries) become excessively permeable (“leaky”), allowing the fluid component to escape from the blood vessels into the peritoneum (causing ascites) and pleural cavity (leading to pleural effusions). This may lead to failure of the circulatory system and shock, followed by death, if circulatory failure is not corrected. In addition, the patient with DHF has a low platelet count and hemorrhagic manifestations, tendency to bruise easily or other types of skin hemorrhages, bleeding nose or gums, and possibly internal bleeding (“Centers for Disease Control and Prevention,” 2010).

15. WHO Case Definition of Dengue
Confirmed Case
Probable Case
Suspect Case
The following case definition was developed by the World Health Organization to assist in accurate diagnosis of dengue:
Suspect case: “Acute onset of high fever of 2-7 days duration and two or more of the symptoms such as Headache, retro-orbital pain, arthralgia, myalgia, rash, hemorrhagic manifestations and leucopenia” (Goel, Gurpreet, and Swami, 2007.)
Probable case: “Suspect case and one or more of the following-
Reoccurrence of confirmed case of dengue in the same place and time along with detection of IgM antibody. IgM antibody indicates current or recent infection and is detectable 6-7 days after the onset of illness. On average Mc-Elisa test is more specific” (Goel, Gurpreet, and Swami, 2007).
Confirmed case: “Suspect/probable case and one or more of the following-
Isolation of virus or detection of viral genomic sequences, four fold rise in titres of IgG or IgM antibodies. For this, at least two samples are taken, one at the time of reporting to a clinic or hospital and the second ,shortly after discharge. Optimum time interval between two samples should be of 10 days” (Goel, Gurpreet, and Swami, 2007)
Laboratory analysis can also confirm the diagnosis of dengue since “the arbovirus causing dengue fever is one of the few types of arbovirus that can be isolated from the serum of the blood” (“Medical Dictionary,” 2010).

16. Societal Cost Increased Social Burden Psychological Distress
Economic Constraints
Dengue epidemics are associated with increased social, psychological, and economic constraints due to required emergency response, ill health, deaths, hospitalization, and loss of productivity (Lloyd, 2003).
Lloyd (2003) further explained that:
The economic impact of DF/DHF is enormous, placing significant burdens on affected communities. This impact varies and can include loss of life; medical expenditures for hospitalization of patients; loss in productivity of the affected workforce; strain on health care services due to sudden, high demand during an epidemic; considerable expenditures for large-scale emergency control actions; and loss of tourism as a result of negative publicity. (Lloyd, 2003, p. 4).

17. Prevention & Control Vector Control Behavior Modification
Community Participation
Supportive Environmental Policies
(“World Health Organization,” 2009)
Prevention and control of dengue is essential, as there is no specific treatment or approved vaccines to prevent dengue.
Primary prevention measures include education campaigns to increase awareness about dengue, community participatory activities to sustain a healthy environment, and mosquito control programs to avoid mosquito bites.
The best way to reduce mosquitoes is to eliminate the places where the mosquito lays her eggs, such as artificial containers that hold water in and around the home.  Look for standing water indoors such as in vases with fresh flowers and clean at least once a week.
The World Health Organization (2009) stated that vector control can be achieved through effective environmental management such as proper solid waste disposal, improved water storage practices (covering water holding containers, and proper disposal of empty plastic containers, used automobile tyres which facilitates the spread of Aedes albopictus, and other items that collect rainwater) to prevent breeding of aedes mosquitoes.
Further evidence was provided to confirm that “the application of small mosquito eating fish in water storage containers has been reported to be successful in mosquito control programs” (“World Health Organization,” 2009).
“Chemical methods include the application of appropriate insecticides to larval habitats, and emergency vector control measures such as broad application of insecticides as space sprays” (“World Health Organization,” 2009).
We are vulnerable to the bites of the adult mosquitoes both during the day and at night when the lights are on. Therefore, certain behavioral practices will assist us in preventing and controlling dengue. Optimal protective measures should include the use of mosquito repellent whether indoors or outside. When possible, long sleeved shorts and long pants should be worn for additional protection. Also, ensure that screens for windows and doors are secure and intact and utilize air-conditioning units if they are available. (“CDC,” 2010).
Community participation, behavior modification, and supportive environmental policies are also essential in the prevention and control of dengue. Measures such as using mosquito bed net and repellent to prevent mosquito bites will assist in controlling the spread of dengue. Appropriate treatment that is initiated early also reduces the severity and mortality associated with dengue
Travelers may utilize the following link to a website that will increase awareness regarding protective measures while travelling especially to known dengue epidemic regions:

18. Prevention & Control Dengue Surveillance Multilateral Partnership
Screening of Blood Product or Organs
The prevalence of dengue is related to unsanitary conditions, poor water management, population growth (specifically urbanization), and the growth and global distribution of the four types of dengue viruses and the Aedes mosquito, especially the Aedes aegypti (WHO, 2009).
Therefore, continuous monitoring of dengue prevention programs can facilitate an early detection of possible epidemics, and the implementation of control measures. Partnership with other countries and organizations are also measures identified to be effective in preventing and controlling dengue as global travel contributes to dengue outbreaks, and joint effort is required in controlling the resilient aedes mosquito population (“World Health Organization,” 2010).
Studies conducted in Puerto Rico and Honduras have confirmed the presence of dengue virus during blood screening. Wilder –Smith, Chen, Massad, and Wilson (2009) however, stated that “despite good evidence for its transmission in healthcare settings, dengue is currently not considered a risk to blood safety”.
Blood screening for dengue prior to blood transfusion, hemodialysis, and organ transplant is therefore necessary to prevent health care acquired dengue infections.

19. Symptomatic Treatment - Bed Rest, Oral Fluids, Pain Relief Medication (No Aspirin)
Aggressive Treatment - Blood Transfusion for Dengue Hemorrhagic Fever
(“WHO,” 2009)
Treatment
There is no specific treatment for dengue due to the viral activity. However measures to relief symptoms include bed rest, increased oral fluid intake, and administration of pain relief medication such as acetaminophen.
Dengue hemorrhagic fever requires aggressive treatment such as blood transfusion by health care professionals. An individual is likely to have repeated episodes of dengue fever; however lifetime immunity from serotype can be achieved through previous exposure.
There are no vaccines to protect against dengue, but according to WHO several potential vaccines are in the developmental stage (“WHO,” 2009).

20. Health and Environmental Implication
Worldwide Problem since the 1950s
One-third of the World’s Population at Risk for Dengue
Difficulty Eliminating the Aedes Aegypti Mosquito due to Its Resilience
(“Centers for Disease Control and Prevention,” 2010)
CDC (2010) reported that “Dengue has emerged as a worldwide problem only since the 1950s, with more than one-third of the world’s population living in areas at risk for transmission”. They also reported that the Aedes Aegypti mosquito has the ability to adapt to the environment and is highly resilient resulting in difficulty to eliminate (“Centers for Disease Control and Prevention,” 2010).

21. Recommendations Regular health education campaigns
Periodic space spraying of insecticides.
Frequent emergency planning and training sessions.
Recommendations
These recommendations will therefore help to sustain an environment where dengue epidemics are prevented.

22. Recommendations Conduct monthly community “clean up campaigns”.
Encourage community participatory research that will assist in the elimination of the aedes mosquito population.
Recommendations
These recommendations will therefore help to sustain an environment where dengue epidemics are prevented.

23. Conclusion
Climatic conditions and rapid growth of Aedes mosquitoes in the Caribbean lead to fear of epidemic
Constant Surveillance, Community Participation and Empowerment are necessary to prevent future outbreaks of Dengue in the Cayman Islands
We will summarize the main points in the presentation at this stage, but first it is important to emphasize that the warm climate, rainy seasons, increased growth in the aedes mosquito population, as well as global travel, urbanization and other poor sanitary conditions in the Caribbean have led to concerns regarding the possibility of a dengue epidemic. The Cayman Islands is located in this geographic region, and although there are reports of a few dengue cases over the years, constant surveillance and community participation is necessary to sustain a healthy environment and conditions that will prevent the transmission of dengue despite the negative climatic and environmental conditions.
The information provided in this presentation will empower individuals to develop practices that will ensure a healthy environment and an island with minimal dengue outbreaks in the future.

24. Summary Dengue is: A global public health concern
The female aedes mosquito acts as an intermediate vector that transmit the virus to humans.
It results in mild symptoms and may progress to serious illness and even death
Dengue is a global public health concern that has reached epidemic proportion in certain regions in the world. This disease is caused by any one of four types of dengue viruses, and may result in mild symptoms of the disease to serious illness and even death. The aedes aegypti mosquito is highly resilient, and acts as an intermediate vector that transmit the virus to humans.

25. Summary
Dengue is associated with poor environmental conditions or vector control
Treatment is often symptomatic
Prevention and control measures includes vector control, community participation, healthy environmental policies and surveillance
Dengue is associated with unsanitary conditions, poor water management, urbanization, global travel, tropical climatic conditions, and growth in the aedes mosquito population. Treatment is often based on symptoms and there are no approved vaccination to offer protection against the dengue virus, therefore prevention and control measures focusing on vector control, community participation, healthy environmental policies and surveillance are essential in the effort to eradicate dengue.

26. References:
Centers for Disease Control and Prevention. (2010, May, 20). Dengue. Retrieved from
Connolly, N. (2010, January, 29). Suspected dengue cases tested. Retrieved from
Goel, N., Gurpreet, M., & Swami, H. (2007). Epidemiological characteristics of dengue fever: Its prevention and control. The Internet Journal of Biological Anthropology, 1(1). Retrieved from
Lloyd, S. L. (2003, February). Best practices for dengue prevention and control in the Americas. U.S. Agency for International Development. Retrieved from
Medical Dictionary. (2010). Dengue fever. Retrieved from
Wilder –Smith, A., Chen, L. H., Massad, E., & Wilson, M. E. (2009, January). Threat of Dengue to Blood Safety in Dengue-Endemic Countries. Emerging Infectious Diseases, 15(1). Retrieved from
World Health Organization. (2009, March). Dengue and dengue hemorrhagic fever. Dengue Net. Retrieved from
World Health Organization. (2010). Impact of Dengue. Retrieved from
World Health Organization. (2010). WHO initiates bi-regional approach to tackle dengue fever in Asia Pacific. Retrieved from

27. Supplemental Resources
Dengue Net – WHO’s Internet-based System for Global Surveillance of Dengue Fever and Dengue Hemorrhagic Fever Website: -
TDR – For Research on Diseases of Poverty (UNICEF, UNDP, World Bank, WHO) Website:
IVR (WHO Initiative for Vaccine Research) Website:
These additional resources will provide relevant and reliable information on dengue.

28. Caribbean Cayman Islands Pictures Photos, 2004 & Dengue- Mosquito.jpg
You may make comments or suggestions at this stage.
Car
Caribbean Cayman Islands Pictures Photos, & Dengue- Mosquito.jpg

29. THANK YOU
Thank you for your participation and attendance at this presentation.