Yellow Fever Resulting from Mosquito Transmission

Yellow fever is an incredibly fatal and infectious disease that is caused by the contraction of a flavivirus. The flavivirus in recent years, has been a severe epidemic in parts of Africa and the tropical regions of Central and South America. The first documented occurence of the disease was in 1648, and of course, much research and further knowledge has been gained since its first observation.

The process of contracting and spreading yellow fever is a very intricate process, and thus a basic understanding of the terminology used is necessary. In instances where the word "host" is used, it is referring to the animal who is infected with the disease; "vector" is in reference to an organism which can be a carrier of the disease, without feeling the effects of the disease. Vectors are able to transmit the disease from one organism to another, without actually experiencing the symptoms of the disease.

Unlike many of the common illnesses, such as the flu, yellow fever cannot be transmitted from one human being to another, rather it is transferred by a vector mosquito. The mosquito draws the infection from a host, which is typically a monkey or human being, and thus the mosqutio begins transmitting the virus to other monkeys and human beings, and the cycle continues.

The transmission of the yellow fever virus doesn't always necessarily result in the development of the infection, an infection develops only roughly ten to twenty percent of the time. Strong immune systems are often able to fight off the infection and mild cases rarely affect the human body.

There are five stages of the infection: incubation, invasion, remission, intoxication, and convalescence. The incubation period lasts for a duration of approximately three to six days, and during this time period few, if any symtpoms are apparent, and the infection inbeds itself into the host. The invasion period lasts about two to five days and the infection symptoms being to appear. Such initial symptoms include: severe headaches, muscle and back aches, nausa, and fatigue. A physical characteristic of the infection is a white coating on the tongue, accompanied with swelling. In the case of high fevers, an increased heart rate can result, which can potentially be dangerous. Additionally, during this invasion period, the infection begins circulating throughout the body and it becomes possible for mosquitoes to transfer the disease.

The period of remission is characterized by a decrease in fever and a decrease in symptom severity. In most instances, this is the last stage of the disease, though in other cases, it can be merely the beginning of the infection process. The intoxication period is considered to be the most brutal of the stages, and it lasts for three to nine days typically. During this stage, certain organs and bodily functions begin to fail, and the patient experiences jaundice, black vomit, and high concentrations of protein in their urine. Due to liver damage, the patient's skin becomes yellow and their eyes white, and this is a result of an increased concentration of bilirubin. Liver damage can also result in excessive bleeding, which can potentially be fatal. For the fortunate patients that survive the intoxication period, there is often a short period of convalescence, in which the body attempts to recover. It isn't possible to be infected by yellow fever more than once, as your body builds up an immunity to the virus after the first experience.

To diagnosis the fever, doctors draw blood from the patient and examine it to look for viral antigens or antibodies that could result from the fever. When Faget's sign occurs (high fever accompanied with low blood pressure), doctors are essentially able to confirm their diagnosis.

There aren't any known treatments for the yellow fever virus, thus doctors try to concentrate on the treatment of the fever's symptoms. Doctors utilize acetaminophen to relieve pain and to attempt to break the fever. They also regulate the fluid intake of the patient, so that dehydration of the body doesn't occur. Additionally, doctors take preventative measures such as antiacids to reduce the risk of internal bleeding. In the event of kidney failure, dialysis is used to clear the body of its toxic substances.

The fatality rate of yellow fever is relatively low, as only five to ten percent of diagnosed cases result in fatality. If a patient suffers from jaundice during the infection, they are much more likely to have fatal consequences. The best approach to controlling the yellow fever transmission, is by taking preventatitive measures to attempt to vaccinate those potentially at risk.