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).
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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