DO NOT COPY. Infectious Diseases: Dengue. Dengue. Aedes Mosquito. Dengue Concentration. Hawaii Dengue Outbreak. Dengue Fever Signs & Symptoms

Transcription

1 Infectious Diseases: Dengue Pacific Emergency Management, Preparedness and Response Information Network and Training Services (Pacific EMPRINTS) University of Hawaii Department of Anthropology Pacific EMPRINTS Dengue Concentration Usually found during and after the rainy season in tropical and subtropical areas: Africa Southeast Asia China India Middle East Caribbean Central America South America Australia South & Central Pacific Hawaii Dengue Outbreak September 2001, Maui. Visitors returning from French Polynesia believed to have brought dengue back with them. Transmission via Aedes albopictus mosquito suspected. Dengue Disease is transmitted by mosquitoes. Caused by one of four related dengue viruses (DEN-1, DEN-2, DEN-3 & DEN-4). Genus: Flavivirus Cannot be infected by each virus type more than once. Also known as break-bone fever. Low case fatality rate. Aedes Mosquito Dengue is transmitted by Aedes mosquitoes: Prefer to breed in artificial containers of water, NOT groundwater or muddy or Aedes aegyptii mosquito. brackish water. and Infectious Diseases, Univ. of Notre Dame Aedes aegyptii is usual vector. Aedes albopictus is less efficient transmitter of dengue: Feeds during daylight but is inactive at night. Does not travel far. No human-to-human transmission. CDC/ Prof. Frank Hadley Collins, Dir., Cntr. for Global Health Dengue Fever Signs & Symptoms Dengue fever can present with any of the following symptoms (in order of frequency of occurrence): 1. Fever (2-7 days) 8. Pruritis 2. Headache 9. Retro-orbital pain 3. Myalgias 10. Diarrhea 4. Arthralgias 11. Cough 5. Nausea or vomiting 12. Bleeding 6. Abdominal pain 13. Hepatomegaly 7. Rash 14. Neurological signs (peripheral neuropathy and encephalitis) The combination of fever with retro-orbital pain and/or severe body aches, thrombocytopenia, and disturbances of taste and sensation are distinctive features of dengue fever. 1

2 Dengue Fever Signs & Symptoms Symptoms milder in children than in adults. At times clinically indistinguishable from influenza, measles, or rubella. Acute phase: Up to 1 week 1-2 weeks of convalescence, characterized by weakness, malaise, and anorexia. Possibility to develop into: Encephalopathy Dengue Hemorrhagic Fever (DHF) Dengue Shock Syndrome (DSS) Dengue Shock Syndrome Early signs of Dengue Shock Syndrome: Restlessness Cold clammy skin Rapid weak pulse Narrowing of pulse pressure Hypotension Advance warning signs of Dengue Shock Syndrome: Severe abdominal pain Protracted vomiting Marked drop in temperature Change in mental status (irritability or obtundation) Dengue Containment Strategies During the beginning phases of a dengue outbreak there is a chance to contain the epidemic using several strategies: Dengue Hemorrhagic Fever Dengue Hemorrhagic Fever patients may display the following signs and symptoms: Fever for 2-7 days Nonspecific symptoms May become restless or lethargic Signs of circulatory failure Thrombocytopenia Hemoconcentration Hemorrhagic manifestations, usually skin hemorrhages, but also including: Epistaxis Bleeding gums Hematemesis Melena The condition of these patients may rapidly evolve into Dengue Shock Syndrome. Treatment No specific treatment: Bed rest. Drink lots of fluids. Take acetominophen to reduce fever. Aspirin is not recommended. Recovery is expected in 2 weeks. Fluid replacement therapy and hospitalization for DHF or serious cases. Dengue Containment Strategies 1. Decrease density of Aedes mosquito vectors by: Eliminating breeding sites. Application of larvicides to breeding sites that cannot be drained. 2. Have public information campaigns about using personal protection against mosquito bites, such as: Bed nets, window screens, repellants and the avoidance of outdoor activity during periods when mosquitoes are active. 3. Strict isolation of dengue-infected patients from further mosquito bites. The virus is transmissible from about a day before the onset of clinical symptoms until the end of fever. 4. Public health authorities may need to work with clinical authorities to disseminate information about clinical management of dengue. **Spraying insecticide around the residential areas where cases have been identified is ineffective in breaking transmission by itself. Mother applies insect repellant to child with bed net in background. CDC. 2

3 Dengue Preventative Measures Apply mosquito repellant. Dress in protective, light-colored clothing. Avoid using heavily scented products. Keep unscreened windows and doors closed and screened windows repaired. Mosquito coils are effective; garlic and Vitamin B are not. No vaccine available. Pacific EMPRINTS The Pacific Emergency Management, Preparedness and Response Information Network and Training Services is funded by the U.S. Department of Health and Human Services Assistant Secretary for Preparedness and Response Grant No. T01HP Sources 1. CDC Dengue Fever Home Page: 2. Gubler DJ, Kano G. Dengue and dengue hemorrhagic fever. Wallingford, UK: CAB International, Dengue drama unfolds Advertiser 10/7/ Ten Have Dengue fever outbreak in Hawaii first in 50 years Pacific Public Health Network Dengue Fever Outbreak Guidelines: Kiedrzynski T. et al. Dengue in the Pacific: an updated story. Pacific Health Dialog 5(1) Morens D. Dengue fever: a prevention summary for Pacific health workers. Pacific Health Dialog 3(1) Prevention and Control of Dengue and Dengue Haemorrhagic Fever. Comprehensive Guidelines. WHO Regional Publication, SEARO No. 29, WHO Regional Office for South-East Asia, New Delhi, Dengue Haemorrhagic Fever: diagnosis, treatment and control. 2nd edition. Geneva, WHO, Vaughan J, Morrow R. Manual of Epidemiology for District Health Management. Geneva, WHO, National Institute of Allergy and Infectious Diseases, National Institutes of Health. September Kuakini Health System: Health & Wellness. Dengue Fever. Found on 6/8/

4 Infectious Diseases: Dengue Pacific EMPRINTS Course Transcript Slide 1: Infectious Diseases: Dengue Welcome to the Infectious Diseases: Dengue tutorial designed by the Pacific Emergency Management, Preparedness and Response Information Network and Training Services at the University of Hawaii at Manoa. Slide 2: Dengue Dengue is a disease transmitted by mosquitoes and caused by one of four related dengue viruses of the genus flavivirus, DEN-1, DEN-2, DEN-3 or DEN-4. It is possible to be infected by all four types of dengue throughout a person s life. However, once a person has contracted one of the virus types, they cannot contract the same type of virus again. Dengue is also known as break-bone fever because it can cause severe joint and muscle pain that, to the patient, feels as though bones are breaking. Despite these painful and uncomfortable symptoms, dengue is rarely fatal and has a low case fatality rate. Slide 3: Dengue Concentration Dengue is a tropical disease found during and after the rainy season in various tropical and subtropical areas of the world, or in other words, where mosquitoes are commonly found. It is often found in Africa, Southeast Asia, China, India, the Middle East, the Caribbean, Central America, South America, Australia, and South and Central Pacific. Although it is not thought of as a disease that is commonly seen in the United States, in 2001 an outbreak occurred in Hawaii. Slide 4: Aedes Mosquito Dengue is transmitted by Aedes mosquitoes that bite dengue-infected people and then transmit the infection to other humans they feed on. Aedes mosquitoes prefer to breed in artificial containers of water, including clogged gutters, water catchment tanks, coconut shells, discarded automobile tires, and septic tanks. Aedes do not breed in groundwater or muddy or brackish water such as can be found in taro patches or mangrove swamps. While Aedes aegyptii is the usual vector for transmission of dengue, Aedes albopictus has also been implicated in dengue outbreaks, including the 2001 outbreak in Hawaii. Aedes albopictus is considered a less efficient transmitter of dengue as it feeds during daylight hours, is inactive at night, and does not travel far. There has never been a case of human-to-human transmission of dengue. Slide 5: Hawaii Dengue Outbreak In September of 2001, health officials discovered an outbreak of dengue on the Hawaiian island of Maui. The outbreak soon spread across the state, as infected persons and mosquitoes traveled around the islands. While unsure of the initial

5 source of the outbreak, epidemiologists suspect that the source of the outbreak was visitors to French Polynesia who returned to Hawaii infected with dengue. While isolated cases of dengue are sometimes found in Hawaii residents, they usually present in individuals who have recently returned from travel to dengueinfected countries, and are prevented from further transmission by spraying the house of the infected individual with insecticide. However, in this case, the dengue infection began in a rural part of the state and was allowed to spread before being brought to the attention of health authorities. Most surprising was the extent of the spread, as Hawaii is not known to be home to the Aedes aegyptii mosquito, but only its cousin, Aedes albopictus, believed to be an inefficient transmitter of dengue. Slide 6: Dengue Fever Signs & Symptoms Dengue fever can present with any of the following symptoms, which are listed in order of frequency of occurrence: Fever (usually lasting for 2 to 7 days), headache, myalgias, arthralgias, nausea or vomiting, abdominal pain, rash, pruritis, retro-orbital pain, diarrhea, cough, bleeding, hepatomegaly, and neurological signs, including signs of peripheral neuropathy and encephalitis. The combination of fever with retro-orbital pain and/or severe body aches, thrombocytopenia, and disturbances of taste and sensation are distinctive features of dengue fever. Slide 7: Dengue Fever Signs & Symptoms Symptoms of dengue fever tend to be milder in children than in adults, and may be clinically indistinguishable from influenza, measles, or rubella. The disease manifestations can range in intensity from unapparent illness to severe illness. The acute phase of dengue fever may last up to 1 week, and is followed by a 1 to 2 week period of convalescence, which is characterized by weakness, malaise, and anorexia. A subset of patients may develop life-threatening complications, including encephalopathy, dengue hemorrhagic fever, or DHF, and dengue shock syndrome, or DSS. Slide 8: Dengue Hemorrhagic Fever Dengue Hemorrhagic Fever, or DHF, is a more severe form of dengue that has the possibility to be fatal. However, if recognized early and managed appropriately, the case fatality rate is less than 1%. Patients with dengue hemorrhagic fever may have fever lasting from 2 to 7 days, and display a variety of nonspecific signs and symptoms. At about the time the fever begins to subside, the patient may become restless or lethargic, show signs of circulatory failure, and experience hemorrhagic manifestations. The most common of these manifestations are skin hemorrhages such as petechiae, purpura, or ecchymoses, but may also include epistaxis, bleeding gums, hematemesis, and melena. Dengue hemorrhagic fever patients develop thrombocytopenia and hemoconcentration, the latter as a result of the leakage of plasma from the vascular compartment. The condition of these patients may rapidly evolve into

6 dengue shock syndrome, or DSS, which, if not immediately corrected, can lead to profound shock and death. Slide 9: Dengue Shock Syndrome Early signs of dengue shock syndrome include restlessness, cold clammy skin, rapid weak pulse, narrowing of pulse pressure and/or hypotension. Advance warning signs of dengue shock syndrome include severe abdominal pain, protracted vomiting, a marked drop in temperature, or change in mental status, including irritability or obtundation. Slide 10: Treatment There is no specific treatment for dengue, other than bed rest, drinking lots of fluids, and taking acetominophen to reduce fever. The Centers for Disease Control and Prevention recommend that patients with dengue fever not take aspirin. Most dengue patients recover fully in approximately two weeks. However, in certain cases, particularly a second infection with another type of dengue, or dengue hemorrhagic fever, there may be life-threatening complications which necessitate emergency treatment. In this case, early recognition of symptoms is essential and fluid replacement therapy and hospitalization are the best treatment options. Slide 11: Dengue Containment Strategies During the beginning phases of a dengue outbreak there is a chance to contain the epidemic using several strategies. The first of these strategies involves decreasing the density of Aedes mosquito vectors by eliminating breeding sites and applying larvicides to breeding sites that cannot be drained. In Hawaii, for example, the density of Aedes mosquitoes can be decreased dramatically by eliminating typical breeding sites within a 100 meter zone around a dwelling because Aedes albopictus does not travel far. A second strategy is to have public information campaigns about using personal protection against mosquito bites such as bed nets, window screens, repellants and the avoidance of outdoor activity during periods when mosquitoes are active. Slide 12: Dengue Containment Strategies A third strategy is the strict isolation of dengue-infected patients from further mosquito bites. This is necessary to contain the virus, which is transmissible from about a day before the onset of clinical symptoms until the end of fever. Finally, public health authorities may need to work with clinical authorities like hospital medical staff, professional associations and local medical schools to rapidly disseminate information about clinical management in order to minimize deaths from dengue. Spraying insecticide around the residential areas where cases have been identified has been found ineffective in breaking transmission by itself. Slide 13: Dengue Preventative Measures Other preventative measures that individuals can take to protect themselves against contraction of dengue entail common sense measures such as the use of

7 mosquito repellant, ideally containing 20 to 30 percent DEET, picaridin, or oil of lemon eucalyptus. Dressing in protective clothing, such as long-sleeved shirts and pants, socks and shoes is also recommended. Dressing in light colors is also a preventative measure, as mosquitoes are attracted to dark colors. Avoid heavily scented shampoos, toiletries, or other products. It is important to ensure that unscreened windows and doors are closed throughout the day and that screened windows are kept repaired. Mosquito coils are an effective repellant, however, garlic and Vitamin B are not. There is currently no dengue vaccine available. It is hoped that a dengue vaccine will eventually be developed, but none are likely to be available for public consumption for at least 5 to 10 years. Slide 14: Sources The displayed sources were consulted in the development of this tutorial. Slide 15: Pacific EMPRINTS The Pacific Emergency Management, Preparedness and Response Information Network and Training Services is funded by the U.S. Department of Health and Human Services Assistant Secretary for Preparedness and Response Grant Number T01HP Sources: 1. CDC Dengue Fever Home Page: 2. Gubler DJ, Kano G. Dengue and dengue hemorrhagic fever. Wallingford, UK: CAB International, Dengue drama unfolds Advertiser 10/7/ Ten Have Dengue fever outbreak in Hawaii first in 50 years Pacific Public Health Network Dengue Fever Outbreak Guidelines: Kiedrzynski T. et al. Dengue in the Pacific: an updated story. Pacific Health Dialog 5(1) Morens D. Dengue fever: a prevention summary for Pacific health workers. Pacific Health Dialog 3(1) Prevention and Control of Dengue and Dengue Haemorrhagic Fever. Comprehensive Guidelines. WHO Regional Publication, SEARO No. 29, WHO Regional Office for South-East Asia, New Delhi, Dengue Haemorrhagic Fever: diagnosis, treatment and control. 2nd edition. Geneva, WHO, Vaughan J, Morrow R. Manual of Epidemiology for District Health Management. Geneva, WHO, National Institute of Allergy and Infectious Diseases, National Institutes of Health. September

8 11. Kuakini Health System: Health & Wellness. Dengue Fever. Found on 6/8/2006