Signs and Symptoms of Yellow Fever

Signs and Symptoms of Yellow Fever

Yellow fever is an acute viral disease which is historically known as 'Yellow Jack' or 'Bronze John' having symptoms like fever, loss of appetite, chills, nausea, head-aches & muscle pains particularly in the back. The improvement of symptoms usually takes 5 days. Abdominal pain, liver damage causing yellow skin, fever occurred within a day of improvement of symptoms in some people.

This virus causing this disease affects the liver in human body. Liver is solely responsible for the production of pigments which determines the colour of our skin. 

When liver gets affected the pigments formation also do not occur normally. As a result of it the skin became yellow. The patient also suffers from the fever in this disease. That's why this disease is called as "Yellow Fever".

The disease is caused by ssRNA virus known as Yellow Fever virus which belongs to the family Flaviviridae. The genus of the virus is Flavivirus. This virus is a 40-50 nm wide single stranded RNA virus which is 11000 nucleotides long. The virus causing yellow fever disease usually is transmitted by the yellow fever mosquito, Aedesaegypti. The Aedes mosquito works as the main vector for this disease though tiger mosquito (Aedesalbopictus) can also serves as a great vector for this disease.

                  

When a mosquito sucks blood from a yellow fever infected man the virus enters to the stomach of the mosquito. If the virus concentration becomes higher in the stomach, the virions then replicate as well as infect the epithelial cells also from the stomach the virus goes to haemocoel first then to salivary glands. When the same mosquito again bites another person the saliva of mosquito containing yellow fever viruses enters the body of the person. Thus the virus causing yellow fever disease transmits to one organism to another.

Signs and symptoms:

Like other diseases this disease also has some unique symptoms. Some of the usual symptoms which get displayed are as follows: In the first 5-6 days no specific symptoms can be found as this is the incubation period for the virus also. After completing this incubation the virus enters to acute phase and finally it proceeds to toxic phase which can be lethal to human also.

Acute Phase: In this acute phase the following symptoms can be found in the body of the patient: 

i) fever ii) dizziness iii) sensitivity to light iv) loss of appetite v) Nausea or Vomiting both vi) red eyes, face or tongue vii) headache viii)Muscle aches, particularly in the back and knees.

Toxic Phase: Signs and symptoms can be disappeared after the commencement of the acute phase though some people enter into a next phase known as toxic phase which can be lethal to human if not treated properly. In this toxic phase the signs and symptoms reappeared with some other more severe symptoms.

I) Liver and kidney failure occurred as the virus highly affects the liver.

II) Slow heart rate medically known as bradycardia

 III) As kidney gets affected by the disease so urine formation also decreases.

IV) Skin colour becomes yellow due to malfunctioning of liver.

V) Eye colour also becomes white causing jaundice.

VI) Bleeding from nose, mouth & eyes occurred followed by abdominal pain and vomiting.