1. ARBOVIRUSES @ A rbovirus means “arthropod-borne virus @ Transmitted by: * Arthropodes: female mosquito's and female ticks * Mother tick transmit virus to her offspring. * In yellow fever and dengue fever humans transmit the virus. @ They are more than 400 arboviruses.

3. PROPERTIES @ Classified into four families: * Togavirus * Flavivirus * Bunyavirus * Reovirus @ Togaviruses: Toga = cloak * Icosahedral capsid, enveloped, single-stranded RNA virus * Divided into two genera: 1.Alphaviruses 2.Rubiviruses (Female tick)

5. @ Flaviviruses: Flavi = yellow * Icosahedral capsid, enveloped, single-stranded RNA virus @ Bunyaviruses: Bunia = town in Africa * Helical capsid, enveloped, segmented RNA virus @ Arbovirus infection results only in Man. @ It does not occur in either arthropod or other animals

7. Arbovirus Diseases in Sudan: @ Yellow fever, @ Dengue fever @ Rift Valley fever Arbovirus Diseases outside Sudan: @ Eastern equine encephalitis @ Western equine encephalitis @ St. Louis encephalitis @ California encephalitis @ Japanese encephalitis @ Colorado tick fever

9. YELLOW FEVER VIRUS Symptoms: @ Jaundice, Fever, Headache, @ Photophobia, Sweating, haemorrhages @ Hematemesis, Shock

10. Yellow fever

11. @ Yellow fever has two cycles: (1) Jungle yellow fever: Found in monkeys in the forest, transmitted to Man by mosquitoes (2) Urban yellow fever: infects Man, transmitted by the mosquitoes

13. Lab.Diagnosis of Yellow Fever: @ Specimens: blood, throat swab, CSF @ Inoculation of: (i) Suckling mice (ii) Cell culture (iii) Mosquito larvae. @ Detect IgM antibody by: * ELISA * Haemagglutinatin–inhibition test.

15. Yellow Fever Vaccine: @ It is a live attenuated vaccine, prepared from 17D yellow fever strain @ Administered in one dose by a subcutaneous injection. @ Protection lasts for 10 years.

17. DENGUE VIRUS Symptoms: @ Fever, malaise, cough, headache. @ Pains in muscles and joints @ Enlarged lymph nodes @ Skin rash @ Haemorrhage in GIT and shock

19. @ Lab. Diagnosis of dengue fever is similar to that of yellow fever @ Dengue virus is transmitted by Aedes aegypti mosquito @ It is transmitted from Man to Man. No animal is involved. @ No vaccine is available. @ Control is by destroying mosquitoes.

21. Rift Valley Fever Virus @ It is a zoonotic disease. @ Man is infected by contact with sheep & cattle; and by mosquito

23. Symptoms: @ Fever, vomiting, haemorrhages Lab. diagnosis of Rift Valley Fever virus: @ Similar to that of yellow fever