Press Release 99/08 JOINT FAO/WHO
RISK OF RIFT VALLEY FEVER MINIMALIZED
IN HORN OF AFRICA, SAYS WHO AND FAO
Rome/Alexandria (Egypt)/ Harare (Zimbabwe), 5 March 1999.- The risk of infection
with the Rift Valley fever virus, for both humans and animals, has been reduced
to minimal or negligible proportions in the countries of the Horn of Africa,
after an epidemic lasting from October 1997 to March 1998 in Tanzania, Kenya,
Somalia and Ethiopia, a joint statement by the World Health Organization
(WHO) and the United Nations Food and Agriculture Organization (FAO) said
The four countries are now in a better than normal situation with regard
to Rift Valley fever and other diseases transmitted through insects to humans
and animals, including malaria in humans; a remarkable improvement due to
both favorable climatic conditions and immunity developed by a large proportion
of livestock infected with the disease in 1997-1998, the joint WHO/FAO statement
"Remote sensing satellite data of climatic conditions fully support ground
observations that conditions in the Horn of Africa countries are highly
unfavorable for multiplication of mosquito vectors of the Rift Valley fever
virus. Therefore, the risk of a Rift Valley fever epidemic occurring soon
is virtually nil," the two UN agencies said.
"Climatic conditions in the four countries since mid-1998 returned to normal
or below normal rainfall amounts and crop growing conditions. Flooding which
would allow multiplication of mosquitoes has not occurred. Thus the risk
of humans or livestock being infected with Rift Valley fever has returned
to historically extremely low levels."
Regarding the export of livestock by the countries of the Horn of Africa
the joint WHO/FAO statement said "the present extremely low risk of Rift
Valley fever infection in livestock is comparable to the risk in former years
that permitted the safe export of livestock."
"The chance of exported livestock being infected with Rift Valley fever virus
and transmitting the disease to humans is at or below the historically extremely
low levels that allowed safe export of livestock in the past," the joint
"The risk may actually be lower than in past years", not only because the
above mentioned climatic factors are highly unfavorable for mosquito
multiplication (therefore virus transmission is negligible), but also because
"a large proportion of the livestock are immune after being infected in 1997-1998
and there is no risk of such livestock transmitting the disease to humans
or other animals," the two UN agencies underlined.
WHO recommended special precautions against mosquito bites in humans working
or travelling in Rift Valley fever infected areas starting in late 1997.
"These special precautions can now be relaxed to normal malaria-specific
precautionary levels in view of the very much diminished risk of Rift Valley
fever," the joint WHO/FAO statement said.
Finally, WHO and FAO underlined that although there have been no reports
of Rift Valley fever for over a year from the epidemic areas in Tanzania,
Kenya, Somalia and Ethiopia, both organizations will continue to monitor
climatic conditions and animal and human health with a focus on Rift Valley
fever. "Subsequent reports by the two organizations will be issued as and
when conditions change," the joint statement indicated.
- For further information, please contact in Rome FAO media officer Mr. Pierre
Antonios (tel.: 39.06.57053473) or FAO expert Dr. David Ward (tel.:
39.06.57056464) and in Alexandria (Egypt) Dr. Bijan Sadrizadeh (tel.: