Rift Valley Fever - A Communicable Disease

Introduction:

Rift valley fever is a viral infection, also known as hemorrhagic fever, that most commonly affects domestic animals in Africa. It is caused by the rift valley fever virus, which belongs to the Bunyaviridae family of the phlebovirus genus. Rift Valley fever is a fatal disease with increased rates of abortion and mortality. It affects the younger animals more often but can also affect humans. Rift Valley fever virus spreads by the bite of mosquitoes (Aedes and Culex genus). In humans, it spreads through livestock and mosquito bites.

How Does This Disease Get Transmitted?

Humans transmit it via blood, fluids, animal tissues, and livestock. Direct exposure to this virus occurs while butchering and caring for sick animals. It spreads through mosquito bites and accidental inhalation of the virus in laboratories.

• The virus can transmit from a female mosquito to its progeny from the eggs.

• The virus remains in the eggs for many years in the dry state.

• Mosquitoes can hatch eggs more in number during rainfall. Heavy rainfall is a significant risk factor.

• Due to the multiplication in the number of mosquitoes, the virus's capability to attack animals and humans increases.

• Rift valley fever virus infects domestic animals, which increases the care for these animals; hence, humans are also exposed to this virus and get infected.

What Are the Signs and Symptoms of Being Infected With the Rift Valley Fever Virus?

After exposure to this virus, the incubation period is between two to six days for symptoms to appear. Mainly, people infected with this virus have no signs or mild to moderate symptoms of fever, fatigue, backache, or dizziness. Usually, the patient's condition improves within one week. Occasionally some people may also develop severe symptoms as follows:

• Eye Diseases: The patient will complain about blurred and decreased eyesight. One to three weeks after these symptoms, eye lesions start appearing. The eye lesions will disappear within 10 to 12 weeks, but in some people, the lesions are present in the center of the retina, and they may experience complete blindness.

• Inflammation of the Brain (Encephalitis): This is a rare symptom, and inflammation leads to headaches, seizures, and coma. These symptoms appear one to four weeks after the initial symptoms. Death is uncommon, but neurological abnormalities persist.

• Hemorrhagic Fever: It is also a rare symptom characterized by jaundice, liver dysfunction, blood in vomiting, blood in stools, bleeding gums, nose, and injection area. These symptoms appear two to four days after the beginning of the disease, and death may occur within three to six days after these symptoms start appearing.

• In Animals: This virus causes more severe symptoms, including fever, fatigue, abortions, and death, especially in young animals.

What Are the Risk Factors Associated With This Disease?

Individuals who live in rural areas and sleep outside their homes at night, where the incidence of rift valley fever occurs, are at a higher risk of getting infected with this virus because of mosquito bites. People who work with animals, especially in the areas where the risk of this infection appears, have a higher chance of getting exposed. Travelers may also be at risk if they visit places where the sickness from this virus is already happening.

How Is Rift Valley Fever Diagnosed?

Blood tests and other sample testings make the actual diagnosis of rift valley fever. The virus can appear in the blood and the postmortem reports via reverse transcriptase polymerase chain reaction (RT-PCR) testing. Antibody testing that utilizes the enzyme-linked immunoassay called ELISA can also be required to confirm the diagnosis. This testing reveals the presence of IgM antibodies in response to infection, and IgG antibodies, which have been present for years. A pen-site or chromatographic strip test is used to check the presence of nucleoprotein, and this test is highly effective for the early detection and cure of rift valley fever.

What Are the Treatment Options Available to Cure This Disease?

There is no treatment plan for rift valley fever because most symptoms are mild and cured independently. Symptoms like fever and body pain can be treated by prescribing over-the-counter medications. Individuals may recover within two days to one week. The severe condition may require immediate hospitalization.

How to Prevent This Infection?

Individuals living in the Rift valley fever prone areas can prevent this illness in the following ways:

1. Prevent contact with the blood and fluids of the infected domestic animals. Individuals working with the animals in the Rift valley fever-prone areas must wear gloves, face masks, and boots to avoid any contact with the blood or fluids of the sick animals.

2. Animal by-products like milk and meat must be properly cooked before consumption.

3. Use insect-resistant sprays, and mosquito nets, for protection from mosquitoes.

4. No vaccines are available for humans against rift valley fever, so precaution is needed to prevent the disease.

5. Animal vaccination is available. The most effective and commonly used animal vaccine is the Smith burn vaccine. It requires only one dose but has side effects like birth deformities and abortion in pregnant animals. This vaccine provides safety in cattle only. Live attenuated vaccines are also available in Africa and are very effective against this virus. Other effective vaccines, like molecular recombinant, are also available.

Conclusion:

Public health education is essential in the ruler areas of Africa to make people aware of the disease and how to prevent it, especially for those living in infection-prone areas. Rift valley Fever is a devastating illness that causes more abortions and deaths. Although it mostly affects younger animals, it can also harm people. It is necessary to guide these people about animal vaccinations and what safety measures should be taken if the disease infects their animals. Public health workers should educate the individuals traveling to these endemic regions about the illness and what safety measures to be implemented while visiting these areas. Individuals should report to a doctor immediately if they notice any of the symptoms mentioned above after traveling to these areas or if individuals are already residing there.