RVF zoonoses


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  • The first outbreak in Egypt was in 1977-1978 following the construction of the High Dam which was followed by flooding and overflowing of riverbanks after heavy rain. The source of the virus was thought to be imported Camels from Sudan. During this outbreak, 18000 human cases and 600 deaths were reported.
  • RVF zoonoses

    1. 1. Dr. Heba Ahmed Sunday, 20 th , March, 2011
    2. 3. Introduction <ul><li>RVF is a viral zoonoses that was first identified in Kenya in 1931. </li></ul><ul><li>primarily affects animals but also has the capacity to infect humans. </li></ul>
    3. 4. Etiology <ul><li>RNA virus belongings to family Bunyviridae, genus phlebovirus </li></ul><ul><li>enveloped, single stranded negative sense RNA virus with 80-120 nm diameter. </li></ul><ul><li>The genome consists of three segments: </li></ul><ul><li>1- Large segment (L) </li></ul><ul><li>2- Medium segment (M) </li></ul><ul><li>3- Small segment (S) </li></ul>
    4. 5. Animal Reservoir <ul><li>Cattle, sheep , camels and goats </li></ul><ul><li>Other animals : African buffalo, black rhino, impala, African elephant, waterbuck and horses </li></ul><ul><li>The virus is spread among animals by the bite of infected mosquitoes </li></ul><ul><li>Age </li></ul><ul><li>Abortion </li></ul><ul><li>PM </li></ul><ul><li>Newborn lambs infected in utero </li></ul>
    5. 6. Insect vector <ul><li>Mosquitoes </li></ul><ul><li>Aedes is the species incriminated in biological transmission </li></ul><ul><li>Glossina , Culicoides , Culex and sand flies </li></ul><ul><li>offspring </li></ul>
    6. 7. Transmission in humans <ul><li>1- The majority of human infections result from direct or indirect contact with blood or organs of infected animals </li></ul><ul><li>2- Inhalation of aerosols </li></ul><ul><li>3- Ingestion of unpasteurized or raw milk from infected animals </li></ul><ul><li>4- Bites of infected mosquitoes </li></ul><ul><li>5- Bites of hematophagous (blood-feeding) flies </li></ul><ul><li>6- Vertical transmission </li></ul><ul><li>7- Contaminated wind </li></ul><ul><li>8- No evidence of human to human transmission </li></ul>
    7. 8. Occurrence Locality Year Great rift valley, Kenya 1931 South Africa 1950-1951, 1953, 1956, 1969 South Africa 1975 Egypt 1977-1978 Egypt 1993 Kenya, Somalia, Tanzania 1997-1998 Saudi Arabia, Yemen 2000-2001 Egypt 2003 Kenya and Somalia 2007 Sudan 2007-2008 South Africa 2010
    8. 9. Occurrence
    9. 10. Occurrence <ul><li>There is a potential of epizootics and epidemics to spread to areas that were previously unaffected </li></ul><ul><li>High prevalence of the disease is reported during periods of heavy rainfall </li></ul>
    10. 11. Clinical Picture In Humans
    11. 12. Clinical Picture In Humans Haemorrhagic fever form Meningeo-encephalitis form Ocular form <1% of patients <1% of patients 0.5-2% of patients Lesions 2-4 days after mild symptoms Lesions 1-4 weeks after mild symptoms Lesions 1-3 weeks after mild symptoms Symptoms Symptoms Symptoms Death within 3-6 days of symptoms Death late is low Death uncommon
    12. 13. Prevention and Control <ul><li>1- Vaccination: </li></ul><ul><li>A- Smithburn vaccine </li></ul><ul><li>B- Formalin inactivated vaccine </li></ul><ul><li>C- Attenuated MP12 vaccine </li></ul><ul><li>D- Clone 13 </li></ul><ul><li>E- Sub-unit recombinant vaccine </li></ul>
    13. 14. Prevention and Control <ul><li>2- Vector control </li></ul><ul><li>3- Public health education </li></ul>
    14. 15. What are the reasons of considering RVF an important zoonotic disease world wide? [email_address]