The Saudi Ministry of Environment, Water and Agriculture is in the process of seeking assistance from specialised companies to provide veterinary services, to combat Rift Valley Fever (RVF), a common animal and human disease, and to prevent epidemic outbreaks in animals and humans, local media reported.

Previous efforts

In 2018, the Minister of Environment, Water and Agriculture, Abdul Rahman Al Fadhli, signed a 47 million riyal contract to provide veterinary services to the Rift Valley Fever Control Programme, for a period of 36 months.

The project aims to raise the level of coverage of these services to combat Rift Valley Fever.

RVF It is an acute, fever-causing viral disease most commonly observed in domesticated animals (such as cattle, buffalo, sheep, goats, and camels), with the ability to infect and cause illness in humans.

It was first reported in livestock by veterinary officers in Kenya’s Rift Valley in the early 1910s.

RVF is generally found in regions of eastern and southern Africa where sheep and cattle are raised, but the virus exists in most of subSaharan Africa, including west Africa and Madagascar. In September 2000, a RVF outbreak was reported in Saudi Arabia and subsequently, Yemen. This outbreak represents the first cases of Rift Valley fever identified outside Africa.

Outbreaks of RVF can have major societal impacts, including significant economic losses and trade reductions.

Transmission

Humans can be infected with RVF from bites of infected mosquitoes and, rarely, from other biting insects that have virus-contaminated mouthparts. More commonly, humans are infected after exposure to blood, body fluids, or tissues of RVF-infected animals. This direct exposure to infected animals can occur during slaughter or through veterinary and obstetric procedures. Infection through aerosol transmission of RVF virus has occurred in the laboratory environment.

No human-to-human transmission has been documented.

Signs and symptoms

RVF virus has an incubation period of 2-6 days following infection and can cause several different disease syndromes.

Most commonly, people with RVF have either no symptoms or a mild illness associated with fever and liver abnormalities. Patients who become ill usually experience fever, generalised weakness, back pain, and dizziness at the onset of the illness. Typically, patients recover within two days to one week after onset of illness.

However, a small percentage (less than 8 per cent) of people infected with RVF develops much more severe symptoms, including:

• Ocular disease (diseases affecting the eye), which sometimes accompanies the mild symptoms described above. Lesions on the eyes may occur 1-3 weeks after onset of initial symptoms with patients reporting blurred and decreased vision. For many patients, lesions disappear after 10-12 weeks; however, for those with lesions occurring in the macula, approximately 50 per cent of patients will have permanent vision loss.

• Encephalitis, or inflammation of the brain, which can lead to headaches, coma, or seizures. This occurs in less than 1 per cent of patients and presents 1-4 weeks after first symptoms appear. Though death from this is rare, neurological deficits, sometimes severe, may persist.

• Hemorrhagic fever, which occurs in less than 1 per cent of overall RVF patients, but fatality for those who do develop these symptoms, is around 50 per cent. Symptoms of hemorrhaging may begin with jaundice and other signs of liver impairment, followed by vomiting blood, bloody stool, or bleeding from gums, skin, nose, and injection sites. These symptoms appear 2-4 days and death usually occurs 3-6 days after.

Risk of exposure

Approximately 1 per cent of humans infected with RVF die of the disease. Case-fatality proportions for infected animals, on the other hand, are significantly higher. The most severe impact is observed in pregnant livestock infected with RVF, which results in abortion of virtually

100 per cent of fetuses

For humans, studies have shown that spending time in rural areas and sleeping outdoors at night in regions where outbreaks occur could be a risk factor for exposure to mosquito and other insect vectors. Animal herdsmen, abattoir workers, veterinarians, and other

individuals who work with potentially-infected animals in RVF-endemic areas (areas where the virus is present) have an increased risk for infection. International travelers increase their chances of getting the disease when they visit RVF-endemic locations during periods when sporadic cases or epidemics are occurring.

Diagnosis

During the early phase of illness in the blood and in postmortem tissue, the virus may be detected using virus isolation.

Treatment

Because most human cases of RVF are mild and self-limiting, a specific treatment for RVF has not been established. The rare, but serious, cases are generally limited to supportive care.

The most common complication associated with RVF is inflammation of the retina (a structure connecting the nerves of the eye to the brain). As a result, approximately 1 per cent - 10 per cent of affected patients may have permanent vision loss.

Prevention

A person’s chances of becoming infected can be reduced by taking measures to decrease contact with blood, body fluids, or tissues of infected animals and protecting themselves against mosquitoes and other bloodsucking insects. Use of mosquito repellents and bednets are two effective methods. For persons working with animals in RVF-endemic areas, wearing protective equipment to avoid any exposure to blood or tissues of animals that may potentially be infected is an important protective measure.

No vaccines are currently available for human vaccination.

Different types of vaccines for veterinary use are available.

SOURCE : GULF NEWS