Dengue Fever Poster

1. Dengue Fever : An Emerging Zoonotic Disease J. Boren and R. L. Stanko Department of Animal, Rangeland, and Wildlife Sciences Texas A&M University-Kingsville Signs and Symptoms These signs and symptoms refer to humans, but the signs are mostly the same for animals as well. In many cases of DF, there are either no symptoms , or only fever with few or no other signs or symptoms [3]. Signs and symptoms that appear will remain 2-7 d. In most cases: High fever (up to 105 °F) Severe headache Rash over face or body (can disappear quickly) In some cases: Low heart rate and low blood pressure Chills Muscle and bone pain Pain behind eyes Nausea and vomiting (especially in children) Mild bleeding (often appears as bruising, or as bleeding gums) Rapid drop in body temperature (a few days after fever onset). A second onset of fever may occur. What is Dengue Fever? Dengue fever (DF) is a virus in the Flaviviridae family and in the Flavivirus genus. It is an “ arbovirus (arthropod-borne virus)” [3]. Virus is passed on mainly through mosquito vectors in the Aedes species and with genus aegypti . The Center for Disease Control [3] says that in rare cases, dengue fever can be spread by blood-to-blood contact, blood transfusions, organ transplants, and from a mother to child during birth, from an infected person to a susceptible person. There are four “serotypes (called DENV-1-2, -3, -4)” [3] of the dengue virus. Once a person becomes infected by one type, he or she will be protected from that strand for life, but that person is still susceptible to the other three forms of the virus. Introduction There are 50-100 million cases of dengue fever (DF) every year world-wide with about 36 million cases with symptoms [1]. 24,000 end in death (mainly children). For more than 150 years before WWII, DF was not very common. WWII led to the spread of the mosquito vector of DF. From 1950-1970 control efforts were in place in the Americas which lessened dengue fever, but since that time, the disease has spread to much of South America and to the southern parts of North America [2]. An increase in urbanization in tropical areas and an increase in world-wide travel has further spread DF. Dengue Hemorrhagic Fever and Dengue Shock Syndrome Dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) are two severe forms of dengue fever. DF can progress into these more extreme forms, but it usually does not. The signs and symptoms of DHF and DSS include those common to DF in addition to several others. DHF can last 2-7 days. It consists of: Bleeding under the skin and from nose and mouth Easy bruising Circulatory collapse (plasma leakage) Abdominal pain Vomiting Cool and clammy extremities Death DSS is the most intense form of the disease. It consists of: Severe abdominal pain Fluid/plasma leakage from blood vessels Heavy bleeding Sudden drop in blood pressure Death Preventions The best ways to prevent the spread of dengue fever include eliminating the mosquito vector population by ridding an area of containers that could house the eggs [3], and reducing the chances of mosquitoes biting by limiting people’s exposure to them [5]. Wearing clothes that cover down to wrists and ankles and wearing socks, shoes, and mosquito netting in an infected area can decrease the chance of being bit. Also, using repellents containing DEET on exposed skin and those containing permethrin on clothing can prevent mosquitoes from biting [5]. Another way to prevent the spread of DF is to refrain from traveling to known dengue-infested areas at peak seasons for the disease. Progression of Dengue Fever The disease starts its transmission cycle when an Aedes mosquito bites an infected individual. The disease then circulates through the mosquito and, 5-12 days later, ends up in its salivary glands [4,5]. The incubation time (“extrinsic incubation period”) needed in the mosquito decreases as temperatures increase [3]. The mosquito then has a few days or weeks (the rest of its life) to transmit the disease to another susceptible individual. On d 4-6 after being bit, the fever and other symptoms begin to appear. In the less severe forms of DF, the signs will last about one week. Full recovery usually occurs within two weeks. In dengue hemorrhagic fever and dengue shock syndrome, an individual may start to recover a few days after the initial fever onset and then get worse. Usually the second round is when the more severe signs and symptoms appear. “Some [people] may feel listless, tired, and even depressed for several weeks to months after being infected” [5]. There is about a five-day window when a mosquito can bite an infected person and start the cycle over. Who is at Risk? Dengue fever is most prevalent in tropical and subtropical areas (because of the presence of DF vectors) [3,4]. Thus, people who live in, or travel to, these areas are most at risk. Young children are also more likely to contract the disease than adults. Those who have had DF before are more likely to develop DHF and DSS during a second infection than an individual who has never before been infected. Weather conditions affect the population size of mosquitoes, so it is easier to contract DF during seasons when mosquitoes are more abundant than during seasons where fewer mosquitoes are present. References [ 1] Shepard , D.S., Coudeville , L. et al . Economic Impact of Dengue Illness in the Americas. 2010. [2] Gubler , D.J. Dengue and Dengue Hemorrhagic Fever. 1998. Clinical Microbiology Reviews. 11:3. p480-96. [3] Centers for Disease Control and Prevention. Dengue. 2010. www.cdc.gov/dengue [4] Cunha, J.P. Dengue Fever. MedicineNet . [5] Mayo Clinic staff. Dengue Fever. 2010. www.mayoclinic.com/health/dengue-fever/DS01028 Dengue fever rash. Retrieved from http://denguefeverpictures.com/ Mosquito vector. Retrieved from http://www.medanku.com/ Acknowledgements T.B. Hairgrove , D.V.M. and P.D. Teel, Ph.D. Funding provided by National Center for Foreign Animal and Zoonotic Disease Defense Treatments There is no cure for DF and there is not yet a marketable vaccine [4,5]. Since it is a virus, there are no treatments for the disease itself, but only for the symptoms. At-home treatments: Drink plenty of fluids to stay hydrated Take drugs with acetaminophen (Tylenol) to reduce fever and pain. Note: Drugs containing ibuprofen should NOT be taken, as these can lead to the symptoms becoming worse [5]. Hospital treatments: Fluids given through an IV Blood transfusions