Dr. Heba AhmedSunday, 20th , March, 2011

IntroductionRVF is a viral zoonoses that was first

identified in Kenya in 1931.

primarily affects animals but also has the capacity to infect humans.

EtiologyRNA virus belongings to family Bunyviridae,

genus phlebovirusenveloped, single stranded negative sense

RNA virus with 80-120 nm diameter. The genome consists of three segments:1- Large segment (L)2- Medium segment (M)3- Small segment (S)

Animal ReservoirCattle, sheep, camels and goatsOther animals : African buffalo, black rhino,

impala, African elephant, waterbuck and horses

The virus is spread among animals by the bite of infected mosquitoes

Age AbortionPMNewborn lambs infected in utero

Insect vectorMosquitoesAedes is the species incriminated in

biological transmissionGlossina, Culicoides, Culex and sand flies offspring

Transmission in humans1- The majority of human infections result from

direct or indirect contact with blood or organs of infected animals

2- Inhalation of aerosols3- Ingestion of unpasteurized or raw milk from

infected animals4- Bites of infected mosquitoes5- Bites of hematophagous (blood-feeding) flies6- Vertical transmission7- Contaminated wind 8- No evidence of human to human transmission

OccurrenceYearLocality

1931Great rift valley, Kenya

1950-1951, 1953, 1956, 1969South Africa

1975South Africa

1977-1978Egypt

1993Egypt

1997-1998Kenya, Somalia, Tanzania

2000-2001Saudi Arabia, Yemen

2003Egypt

2007Kenya and Somalia

2007-2008Sudan

2010South Africa

Occurrence

OccurrenceThere is a potential of epizootics and

epidemics to spread to areas that were previously unaffected

High prevalence of the disease is reported during periods of heavy rainfall

Clinical Picture In Humans

Clinical Picture In HumansOcular formMeningeo-

encephalitis formHaemorrhagic fever form

0.5-2% of patients<1% of patients<1% of patients

Lesions 1-3 weeks after mild symptoms

Lesions 1-4 weeks after mild symptoms

Lesions 2-4 days after mild symptoms

SymptomsSymptomsSymptoms

Death uncommonDeath late is lowDeath within 3-6 days of symptoms

Prevention and Control1- Vaccination:A- Smithburn vaccineB- Formalin inactivated vaccineC- Attenuated MP12 vaccineD- Clone 13E- Sub-unit recombinant vaccine

Prevention and Control2- Vector control

3- Public health education

What are the reasons of considering RVF an important zoonotic disease world wide?heba_ahmed_77@yahoo.co.uk