Determining the incidence of Dengue in Ile-Ife

Pyrexia of unknown origin (PUO) is fever that occurs for no apparent reason with failure toestablish diagnosis within one week of investigation. The fever involves temperatures ofgreater than 38.3oC which occurs sporadically for more than three weeks. Fever resolvesusually after about 3 days but can take 2 weeks.Dengue is a tropical mosquito borne-viral disease and is marked by high fever and severe muscle and joint pains. It is caused by any of four antigenically and genetically distinct viruses of the family flaviviridae, named denv-1, denv-2, denv-3 and denv-4 (Craven, 1991). It is therefore possible to get dengue fever multiple times, as an attack of dengue produces lifetime immunity to that particular serotype to which the patient was exposed. Humans are the primary vertebrate host of these viruses, although there is evidence of a silent zoonotic cycle involving monkeys in parts of Asia and Africa (Cordellier et al., 1983).Dengue fever is characterized by an abrupt onset of fever, headache, myalgia, loss of appetite and varying gastrointestinal symptoms often accompanied by bone and joint pains (Ehrenkranzetal., 1979). Symptoms persist for 3–7 days, and while convalescence may be prolonged for several weeks, mortality is rare. Homologous immunity is lifelong, but cross-protection to other dengue viruses is not elicited and, indeed, there is evidence to suggest that heterologous antibodies may form infectious immune complexes which may increase the severity of subsequent infections (Kliks et al., 1989).Dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS) are more severe manifestations of dengue infection, and are most often associated with infection of people with pre-existing antibodies to dengue, either passively or actively acquired i.e. antibody dependent enhancement (Halstead et al., 1980). 

INTRODUCTION                    1
1.2 Aims and Objectives        3
2.2 The Dengue Virus            6
2.2.1 Replication Cycle           7
2.3 Epidemiology                    9
2.3.1 Outbreaks of Dengue fever in West Africa    12
2.4.2 Laboratory Diagnosis    13
2.5 Transmission                    14
2.6 Pathogenesis                    15
2.6.1. Prognosis                      16
2.6.2.2 Dengue Shock Syndrome (DSS)            18  
2.7 Treatment                         19
2.8.2 Mosquito Control             21
2.8.3 Control of Outbreak         22
3.2 Materials                             23
3.3 Principle of the Test             24
3.4 Sample Collection                25
3.5 Test Procedure                    25
3.6 Safety Considerations          27
4.1 Anti-Dengue IgM antibody and age distribution    28
4.2 Anti-Dengue IgM antibody and sex distribution    30
4.3 Anti-Dengue IgM antibody and Malaria parasite tests results    32
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