Key words and abbreviations:

Zoonosis: a disease that normally occurs in animals but can be transmitted to humans.

CDC: Centers for Disease Control

RVF: Rift Valley Fever

RVFV: Rift Valley Fever Virus

WHO: World Health Organization

A multidisciplinary team, led by Dr. Patrick Tusiime, the District Health Officer, has done an outstanding job of containing the outbreak of Rift Valley Fever (RVF) in Kabale Municipality, South West Uganda. The team has been working in close collaboration with the CDC and the WHO.

There have been no new cases of RVF since the initial two were reported one month ago.

The first case was an adult male in Bugongi suburb of Kabale Town who operated an illegal butchery. According to a member of the RFV Task Force, some of the animals slaughtered by the Bugongi butcher had been stolen from their owners.

The second case was a 15-year old male student from Kicumbi, off Katuna Road, who was a herd boy and had had close contact with animals.

Upon identification, the two patients were immediately placed in isolation at Kabale Regional Referral Hospital (KRRH) and appropriate contact surveillance measures instituted.

Both patients are now clinically well, but they are still positive for the virus particles. The teenager is still in isolation.

Dengue, zika and chikungunya fever mosquito (aedes aegypti) on human skin
Aedes Egypti mosquito feeding on (and infecting) a human

RVF is a zoonosis that is caused by a mosquito-borne Rift Valley Fever Virus (RVFV). This virus, ((family Bunyaviridae ; genus Phlebovirus ) causes serious disease in sheep, goats, cattle and humans. Exotic breeds of these animals, especially those from Europe, are at a higher risk of severe disease. So far there is no conclusive evidence to suggest that wild animals can be amplifiers of the disease.

It was first reported from Kenya in 1930 after the death and abortions of sheep on a farm near Gilgil, north of Lake Naivasha. Earlier reports of death and abortion in Kenyan sheep in 1913 may well have been due to RVF.

Whereas RVF was exclusively reported from continental sub-Saharan Africa before 1977, it has since spread to Madagascar, Comoros, Egypt, Yemen and Saudi Arabia.

RVF is closely associated with high rainfall conditions.

The Aedes mosquito is the major vector for vertical transmission. Other known transmitters are the Culex, Anopheles, Coquillettidia, Mansonia and Aretmapodites mosquitoes. Sandflies and other flies might also be potential vectors.

Humans can get infected through direct contact with fluids and tissues of affected animals, including aborted fetuses, uncooked meat and amniotic fluids. Unpasteurized milk may also be a risk factor.

Risk prediction is now possible by using a combination of monitoring global climate indicators and regional and local vegetation development, rainfall, and land surface temperatures.

Control measures include RVF monitoring, ground surveillance, animal vaccination and vector control.

Human infections are generally self-limiting. However liver disease, eye disease (retinitis) or a hemorrhagic (bleeding) disorder may occur. Up to 30 percent of hospitalized cases die.

Delayed-onset of confusion, unsteadiness, seizures (fits) and coma) can occur 7–28 days after resolution of the acute illness.

Who is at risk of getting the disease?

Pastoralists, shepherds, farmers, butchers, and laboratory workers and veterinarians working with RVFV are also at high risk.

Rift Valley Fever Distribution Dark blue: Periodic widespread epidemics Mid-blue: Occasional outbreaks Source: Hunter’s Tropical Medicine and Emerging Infectious Diseases (2013)




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