Causes of Yellow Fever and How We Can Prevent It

 

Causes of Yellow Fever and How We Can Prevent It

What is it?
Yellow fever, also known as Siam disease or Barbados fever, is a rapidly evolving, acute infectious disease transmitted by the bite of the mosquito. The severity can be very variable; Regardless of its intensity, once suffered, the patient acquires lifelong immunity. It generally manifests itself in high-mortality outbreaks in the African, Central and South American regions.

The number of people infected with this disease has increased in the last two decades due to a decrease in the immunity of the population, deforestation, population movements, climate change and urbanization. For a Vaccine for yellow fever, visit Travel Clinic in Bexley.

Causes
Yellow fever is caused by a virus that is transmitted by the bite of mosquitoes. A person can become infected if the mosquito is infected with the virus.

Despite being a disease that is localized in specific countries of the world (especially in South America and sub-Saharan Africa), anyone can be infected, although older people have a higher risk of reaching the severe stage of the disease.

Symptoms.
Once the virus is contracted and after an incubation period of 3 to 6 days, the infection can develop in one or two phases, depending on how the disease evolves:

The first stage or acute phase: In this first period, the most common symptoms are fever, myalgia with severe back pain, chills, headaches, nausea or vomiting and loss of appetite. Later, most patients improve and symptoms resolve within 3 to 4 days. The second stage or toxic phase: 15 per cent of patients reach this state. In this case, the fever becomes higher and different organ systems are affected.

Afterwards, the patient becomes jaundiced and complains of abdominal pain with vomiting. In addition, oral, nasal, eye or gastric bleeding, blood in vomit or stool, and kidney failure may occur. Half of the patients who enter this phase die within 10 to 14 days and the rest recover without serious damage to their organs.

Prevention
Vaccination is the most effective measure against contagion, which is why the World Health Organization (WHO) recommends it for any trip outside urban areas in countries located in areas of Central and South America and part of Sub-Saharan Africa. This vaccine must be administered in official vaccination centres accredited by WHO.

One dose provides immunity for ten years from the tenth day of administration. It causes adverse effects, such as local pain, muscle aches or headaches, and fever may also appear. It is contraindicated during pregnancy, in people allergic to eggs, in immunosuppressed patients and in children under nine months of age.

Other prevention measures are avoiding mosquito bites and controlling their reproduction.

Types
Those most affected by yellow fever are humans and monkeys. Its transmission can occur from one animal to another or by the bite of a mosquito. It can be classified into three types according to its three different forms of transmission.

Jungle: It occurs in tropical forests. It is caused by the bite of a carrier mosquito. It is usually rare but affects mainly monkeys, which in turn can infect other mosquitoes that feed on their blood and these to people who enter the jungle.

Intermediate: Typical of the humidor semi-humid savannas of Africa. It produces several cases simultaneously and in separate populations. It causes few deaths, but if left unchecked, it can generate the most serious urban yellow fever epidemic.

Urban or epidemic: The Aedes aegypti mosquito acts as a transmitting agent between people in areas of high population density, being able to generate large epidemics where the virus is transmitted from one person to another with great ease.