KENYA RIFT VALLEY FEVER
Kenya- Rift valley Fever Outbreak (8 June, 2018)
Following the confirmation by the
Ministry of Health, Kenya the outbreak of Rift Valley fever on the 8 of June
2018. As of 16 June, a number of cases
has been reported from different parts of the country; Wajir 24 cases and Marsabit counties 2 cases. The first patient was admitted to a
hospital in Wajir County in north-eastern Kenya on the 2nd of June with fever, body weakness, and bleeding
from the gums and mouth. The patient reported having consumed meat from a sick
animal; the patient died the same day. On 4 June, two relatives of the index
patient were admitted. Blood samples were collected and sent to the Kenya
Medical Research Institute, one of which was confirmed positive for Rift Valley
fever on 6 June. A high number of deaths and abortions among livestock,
including camels and goats, has been reported in Garissa, Kadjiado, Kitui,
Marsabit, Tana River, and Wajir counties. People living in these counties were
reportedly consuming meat from dead and sick animals.
According to WHO Preparedness
activities for Rift Valley fever have been ongoing since February 2018 in
reaction to the heavy rains and flooding in Kenya. An alert was issued to all
County Directors in February 2018 and a general national alert was communicated
in May 2018.
The following actions have been
taken since the outbreak was confirmed:
- On 8 June, the MoH and Ministry of Agriculture convened
an emergency meeting with the Ministry of Livestock (MoL) and key
stakeholders. A health sector task force meeting was held, and partners
pledged their support to Rift Valley fever control.
- On 14 June, the MoH activated the Emergency Operations
Centre, with an Event Manager and supporting technical team.
- On 14 June, a multi-sectoral investigation teams was
deployed in Wajir County to support the county health teams. Another team
will soon be dispatched to support the Marsabit County team.
- As part of ongoing preparedness activities, active
surveillance for Rift Valley fever is being strengthened in affected and
at-risk counties, as well as contact tracing in Wajir and Marsabit
counties. In Wajir County, five treatment centres have been established.
- Active case searching and community sensitization
activities are ongoing in the affected areas. Guidelines for vector
control and other informational materials have been dispatched to Wajir
County, and messages are being disseminated through Community Health
Volunteers.
- A ban on slaughtering animals and restriction of
livestock movement has been imposed in the affected areas.
WHO
risk assessment
Outbreaks of Rift Valley fever are
not uncommon in Kenya. The last documented outbreak occurred from November 2014
through January 2015 in north-eastern Kenya; in 2006, a large outbreak killed
more than 150 people. The CFR has varied widely in documented outbreaks but the
overall CFR tends to be less than 1%.
Kenya’s prior experience with
responding to Rift Valley fever outbreaks combined with the preparedness
activities undertaken over the preceding months is of benefit. However, the
high number of reported deaths and abortions in livestock is concerning, especially
because the event affects nomadic communities for which diet is predominantly
based on animal products. The high volume of movement of cattle and people in
this area increases the risk of further spread of the outbreak both within
Kenya, and to neighbouring countries.
WHO
advice
Rift Valley fever is a
mosquito-borne viral zoonosis that primarily affects animals but also has the
capacity to infect humans. The majority of human infections result from direct
or indirect contact with the blood or organs of infected animals. Herders,
farmers, slaughterhouse workers and veterinarians have an increased risk of
infection. Awareness of the risk factors of Rift Valley fever infection and
measures to prevent mosquito bites is the only way to reduce human infection
and deaths. Public health messages for risk reduction should focus on:
- Reducing the risk of animal-to-human transmission
resulting from unsafe animal husbandry and slaughtering practices.
Practicing hand hygiene and wearing gloves and other personal protective
equipment when handling sick animals or their tissues or when slaughtering
animals is recommended.
- Reducing the risk of animal-to-human transmission
arising from the unsafe consumption of raw or unpasteurized milk or animal
tissue. In endemic regions, all animal products should be thoroughly
cooked before eating.
- Reducing the risk of mosquito bites through the
implementation of vector control activities (e.g. insecticide spraying and
using larvicide to reduce mosquito breeding sites), use of
insecticide-impregnated mosquito nets and repellents, and wearing light
coloured clothing (long-sleeved shirts and trousers).
- Restricting or banning the movement of livestock to
reduce spread of the virus from infected to uninfected areas.
- Routine animal vaccination is recommended to prevent
Rift Valley fever outbreaks. Vaccination campaigns are not recommended
during an outbreak as they may intensify transmission among the herd
through needle propagation of the virus. Outbreaks of Rift Valley fever in
animals precede human cases, thus the establishment of an active animal
health surveillance system is essential to providing early warning for
veterinary and public health authorities.
WHAT IS RIFT VALLEY FEVER:
Rift Valley fever
is a viral disease that can cause mild to severe symptoms. The mild symptoms
may include: fever, muscle pains, and headaches which often last for up to a
week. The severe symptoms may include: loss of sight beginning three
weeks after the infection, infections of the brain causing severe headaches and
confusion, and bleeding together with liver problems which may occur within the
first few days. Those who have bleeding have a chance of death as high as 50%.
The disease is caused by the Rift valley fever virus, which is of the Phlebovirus type. It is spread by
either touching infected animal blood, breathing in the air around an infected
animal being butchered, drinking raw milk from an infected animal, or the bite
of infected mosquitoes. Animals such as cows, sheep, goats, and
camels may be affected. In these animals it is spread mostly by mosquitoes. It
does not appear that one person can infect another person. The disease is
diagnosed by finding antibodies against the virus or the virus itself in the blood.PREVENTION:
Prevention of the disease in humans is accomplished by vaccinating animals against the disease. This must be done before an outbreak occurs because if it is done during an outbreak it may worsen the situation. Stopping the movement of animals during an outbreak may also be useful, as may decreasing mosquito numbers and avoiding their bites. There is a human vaccine; however, as of 2010 it is not widely available. There is no specific treatment and medical efforts are supportive.
Outbreaks of the disease have only occurred in Africa and Arabia. Outbreaks usually occur during periods of increased rain which increase the number of mosquitoes. The disease was first reported among livestock in Rift Valley of Kenya in the early 1900s, and the virus was first isolated in 1931.
Signs and symptoms
In humans, the virus can cause several syndromes. Usually, sufferers have either no symptoms or only a mild illness with fever, headache, muscle pains, and liver abnormalities. In a small percentage of cases (< 2%), the illness can progress to hemorrhagic fever syndrome, meningoencephalitis (inflammation of the brain and tissues lining the brain), or affect the eye. Patients who become ill usually experience fever, generalised weakness, back pain, dizziness, and weight loss at the onset of the illness. Typically, people recover within two to seven days after onset. About 1% of people with the disease die of it. In livestock, the fatality level is significantly higher. Pregnant livestock infected with RVF abort virtually 100% of foetuses. An epizootic (animal disease epidemic) of RVF is usually first indicated by a wave of unexplained abortions. Other signs in livestock include vomiting and diarrhoea, respiratory disease, fever, lethargy, anorexia and sudden death in young animals.The virus belongs to the Bunyavirales order. This is a family of enveloped negative single stranded RNA viruses. The virus' G(C) protein has a class II membrane fusion protein architecture similar to that found in flaviviruses and alphaviruses. This structural similarity suggests that there may be a common origin for these viral families.The virus' 11.5 kb tripartite genome is composed of single-stranded RNA. As a Phlebovirus, it has an ambisense genome. Its L and M segments are negative-sense, but its S segment is ambisense. These three genome segments code for six major proteins: L protein (viral polymerase), the two glycoproteins G(N) and G(C), the nucleocapsid N protein, and the nonstructural NSs and NSm proteins.
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