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2.3.12 TREATMENT OF DENGUE VIRUS INFECTIONSThe World Health Organization has formulated specific guidelines for themanagementof cases (WHO, 1982). Principles of treatment are dictated by the needto closely monitor the patient's vital signs and hematocrit and to replace plasmavolume by judicious fluid replacement. Oxygen should be administered; moreover,if disseminated intravascular clotting is documented, consideration may be given toheparin therapy. Blood transfusion is indicated only in the case of severehemorrhage. Salicylates and hepatoxic drugs should be avoided. Corticostreroidsare widely used; evidence for their usefulness is conflicting, but some studiesindicate that they are of no value (Sumarmo et al., 1982).Specific, antiviral' therapy has not been extensively evaluated. Anuncontrolled trial of interferon was conducted during the 19~ 1 epidemic in Cuba,with some indications that deaths may have been averted. Although ribavirin showsill vitro activity against dengue virus, concentrations required for ill vivo efficacy arenot achievable without toxicity. A study of ribavirin in dengue-infected monkeysfailed to show an antiviral effect (Malinosky et al., 1990).2.4 WEST NILE VIRUS INFECTIONS IN NIGERIAIt has been reported that WNV and other viral types including otherarboviruses were isolated from livestock in the northern part of Nigeria between1966-1970 (Kemp et al., 1973). Since then, the most recent study on the status ofWNV infections in Nigeria was in 1990 where haemagglutinating Inhibitionantibodies (HI) were demonstrated in both animals and humans (Olaleye et al.,1990). That study covered the Rain Forest (Ibadan) and Sahel savanna (Maiduguri)ecological zones. Another report also revealed the presence of complement fixingantibodies (CFA) in humans and dornestiic animals (Omilabu et al., 1990).Therefore the endemicity of the virus in Nigeria cannot be over emphasized2.4.1 THE PATHOGENESIS OF WNVThe pathogenesis of WNV is similar to that of other Flaviviruses (Kundin etal., 1963; Nathanson, 1980) described above. Avian pathogenesis is distinctive inthat visceral organs are affected, with deaths from myocarditis as well asencephalitis (Stee1e et al., 2000) Virus is shed in cloacal fluids and bird -to bird41