Monday, June 30, 2014

Yellow fever: Symptoms, Diagnosis and treatment

Yellow fever, also known as yellow plague or yellow jack, is a disease caused by the bite of female mosquito. It only affects humans and some other primates. It is caused by a RNA virus with same name by species of mosquito called Aedes aegypti. Some other species can also transmit it. It is called yellow fever because of the jaundice it causes to some patients.

Symptoms – Symptoms of this disease are fever, headache, back pain, abdominal pain, chills, loss of appetite, vomiting, nausea, and muscle pain. These signs usually improve between three to five days. In most of the cases, it only last for a few days but in some other cases, it can move to its next level. In the second level of this disease, it can cause liver damage and jaundice. With abdominal pain and fever, bleeding also begins from eyes. It also affects the functions of kidney. Sometimes, vomits also contain blood.

Once you survive it, it provides you yellow fever immunization for life.

Once the virus is transmitted in the human body, it enters the blood stream and infects dendritic cells.

Diagnose - Sometimes it is difficult to differentiate this disease from normal illness because of its flu like symptoms. In the early stages, it can be confused with other flu like diseases. It is diagnosed by blood sample, which is tested with reverse transcription Polymerase chain reaction (PCR).

Vaccination – The vaccine used for this disease is called 17D, which is in use since 1950s. It was developed by a South African-American doctor Max Theiler in 1937. It provides immunity for ten years or in some case more than that. He received Nobel Prize in Physiology or Medicine in 1951 for his work.

It is believed that it originated in East or Central Africa. Experts believe that it was introduced to America with the slave from Africa in Colonial times. There is no particular treatment available for yellow fever. One can only take care of the symptoms in patients, such as fever, dehydration, or pain. It can be prevented by reducing the population of mosquitos by killing developing larvae. To kill larvae, techniques such as larva-eating fish and copepods and larvicides are used.

It is common in the tropical and subtropical areas of Africa and South America. Vaccination for yellow fever is recommended for the people who are planning a trip to the countries in these areas.