Introductions for Dengue fever (sample)

INTRODUCTION             Dengue fever, also known as breakbone fever, dandy fever (because of pain in the joints and bones and the way the patient seems to be walking on his toes) is an acute febrile disease caused by infection with one of the serotypes of dengue virus which is transmitted by mosquito genus Aedes; a benign syndrome caused by several arthropod-borne viruses, is characterized by biphasic fever, myalgia or arthralgia, rash, leukopenia, and lymphadenopathy.             There are at least four distinct antigenic types of dengue virus, members of the family Flaviviridae. In addition, three other arthropod-borne (amboviruses) cause similar or identical febrile diseases with rash.             The causative agent is the arbovirus, namely, Onyong-onyong, Chikungunya, West Nile, Flavirus; it is transmitted by bite of an infected mosquito, principally the female Aedes Aegypti, it is a day biting (they appear two hours after sunrise and two hours before sunset), it has a limited and low- flying movement, breeds on clear- stagnant water for drinking or bathing and in rainwater collected in any container, has grey wings and white stripes on the body and white bands on the legs. It is characterized by capillary permeability, abnormalities of homeostasis, and in severe cases, a protein- losing shock syndrome (dengue shock syndrome).  It is currently thought to have an immunopathologic basis.             Epidemics were common in temperate areas of the America, Europe, Australia, and Asia until early in the 20th century. Dengue fever and dengue-like disease are now endemic in tropical Asia, tropical Africa. Dengue fever occurs frequently among travelers to these areas.             Most disease occurs in older children and adults. Because A. aegypti has a limited range, spread of an epidemic occurs through viremic human beings and follows the main lines of transportation. Sentinel cases may infect household mosquitoes; a large number of nearly simultaneous secondary infections give the appearance of a contagious disease. Where dengue is endemic, children and susceptible foreigners may be the only persons to acquire overt disease, adults having become immune.             The incubation period is 5-7 days. The clinical manifestations are variable and are influenced by the age of the patient, in infants and young children the disease may be undifferentiated or characterized by fever for 5-7 days, pharyngeal inflammation, rhinitis, and mild cough. A majority of infected older children and adults experience sudden onset of fever, with temperature rapidly increasing to 39.4-41.1 degree Celsius, usually accompanied by frontal or retro-orbital pain, particularly when pressure is applied to the eyes. Occasionally, severe back pain precedes the fever (black-break fever). A transient, macular, generalized rash that blanches under pressure may be seen during the first 24-48 hr of fever. Myalgia and arthralgia occur soon after the onset and increase in severity. Joint symptoms may be particularly severe in patients with chikungunya or onyong-onyong infection. From the 2nd-6th days of fever, nausea and vomiting are apt to occur, and generalized lymphadenopathy, cutaneous hyperesthesia or hyperalgia, taste aberrations, and pronounced anorexia may develop.  The pathopnomonic sign of Dengue/Hemorrhagic Fever is Herman’s sign. It appears on the upper and lower extremities, purplish or violaceous red with blanched areas about 1 cm or less in size. Grade 1 manifestations/ and signs and symptoms. ·         Sudden  high fever for 5-7 days; sore throat ·         Redness of the eyeballs, swollen face ·         Pain: periorbital, joints, bones, abdomen, head, on eye movement ·         Nausea and vomiting Pathological changes a.    Petechiae b.    Herman sign: general redness of the skin c.    Macular or measles-like rash on the palms and spreads up the arms, body and legs. Fades slowly and followed by branny desquamation of the skin. Grade 2- signs and symptoms of grade 1 plus ·         Bleeding a.    Epistaxis (nose) b.    Gums c.    Gastric * Hematemesis (vomiting of blood) * Melena (passage of blood) * Hematochezia (stool with fresh blood)             Grade 3- signs and symptoms of grade 2 plus evidence of circulatory failure ·         Cold, clammy skin ·         Hypotension ·         Very rapid but weak pulse ·         Very rapid respiration Grade 4-signs and symptoms of grade 3 plus signs of hypovolemic shock (due to excessive bleeding/ blood loss). May lead to death if uncontrolled. The Diagnostic and laboratory exams to be considered are Tourniquet or Rumpel Leede Test; it is a presumptive test for capillary fragility, Platelet count that it should be below or <150,000cu.Mm for positive results of dengue and it should be done every six hours, and hematocrit count that it should be above or > 0.34-0.54 because of hemoconcentration. Life Cycle of a Mosquito Under optimal conditions, the egg of a mosquito of the genus Aedes can hatch into larvae in less than a day. The larva then takes about four days to develop in a cocoon from which adult mosquitoes will emerge after two days. Three days after the mosquito has bitten someone and taken in the blood, she will lay eggs and the cycle begins again.  Some facts about mosquitoes: ·         Only the female Aedes mosquito bites as it needs protein in blood to develop eggs. ·         The mosquito becomes infectious after about 7 days, it has bitten a person carrying the virus. It is the extrinsic incubation period, during which the virus replicates in the mosquito and reaches the salivary glands. ·         Peak is bite at dawn and dusk. ·         The average lifespan of a mosquito of the genus Aedes in Nature is 2 weeks ·         Mosquitoes may lay eggs about 3 times in his life, and about 100 eggs are produced each time. ·         The eggs can live in dry conditions until approximately 9 months, after which they can hatch if it is subject to conditions, example:  food and water