New West Nile fever on the rise: Symptoms, Causes and Treatment
The West Nile fever is an infectious disease that is transmitted by mosquitoes to humans. More and more people in the United States are suffering from the so-called West Nile fever. Some sufferers even died of the disease. Its pathogen, the West Nile virus, occurs in Africa, North America and southeastern Mediterranean countries. Often the infection remains asymptomatic. This means that the affected person does not suffer from any symptoms. Some patients suffer from flu-like symptoms. Severe courses are rare but can be fatal. We explain what is behind the West Nile virus and how the symptoms of fever in humans are expressed.
What is West Nile Fever and its Causes?
The virus belongs to the family of Flaviviruses and can occur in both tropical and temperate areas. It consists of the genome (RNA) and a shell in which various proteins are incorporated.
The virus is transmitted via bites of mosquitoes. Other animals in which the virus lives are mostly birds. But even horses and cats can be infected.
If a mosquito stings one of these animals, it picks up the viruses on its trunk. If she subsequently stings a human, she can transmit the West Nile virus to her.
They serve the virus mainly as a host or as a reserve and ensure the widespread distribution of the virus. In rare cases, the virus is also transmitted from person to person.
However, this can only be seen in blood transfusions, organ transplants or when breastfeeding from mother to baby. But these transmission paths are very rare.
Symptoms of West Nile Fever
West Nile fever remains asymptomatic in almost 80 percent of cases. Doctors speak of a clinically silent infection. About 20 percent of patients have sudden onset but they experience mild symptoms. These are similar to the flu.
In the majority of the infected, the disease is without symptoms and it is not perceived at all. Only about one in five symptoms occur at all.
These are then very similar to flu, which is why the West Nile fever is often not identified as such, but falsely dismissed as the flu. The symptoms occur about 2-14 days after infection.
Typical complaints are chills, fever, head and body aches, conjunctivitis, dizziness and vomiting.
The symptoms start suddenly and usually end without treatment within six days. Often also occur rashes on the whole body.
In some cases, inflammation of the meninges or encephalitis may occur during the course of the infection. These can theoretically also take a fatal course. This is rare.
Affected are then old people or people with a suppressed immune system. If the central nervous system is affected, paralysis may also occur which, unfortunately, has a poor prognosis for recovery.
In humans, in 80 percent of all cases, no symptoms develop; the infection with the West Nile virus therefore usually goes unnoticed.
The remaining 20 percent of cases show flu-like signs. The incubation period is two to 14 days. Symptoms that are typical of West Nile fever may include:
- headache body
- lymph node swelling
- diarrhea and vomiting
- loss of appetite
After the first fever, there may be an initial relief of symptoms. Thereafter, however, the fever increases again (biphasic course).
At the end of the fever phase, a little less than half of those affected patients report a rash lasting about one week. Usually, the disease heals by itself.
Complications of West Nile Fever
West Nile fever can also be severe because the virus is able to cross the blood-brain barrier. This can cause encephalitis(inflammation of the brain), meningitis (inflammation of the meninges) or paralysis (acute paralysis).
These complications can cause permanent damage or even death.
According to experts, the virus can also lead to kidney failure or affect other organs such as the pancreas, heart or eyes.
Infection with the West Nile virus can still be delayed even months after the symptoms have resolved. These include symptoms such as tiredness, muscle aches or difficulty concentrating.
Diagnosis of West Nile Fever
If you feel chipped off during or after a trip to endemic areas and get a high fever, see a doctor. It is not easy to diagnose West Nile fever as there are many diseases with similar symptoms.
In the preliminary discussion, your doctor will ask you the following questions:
- Since when do you feel sick?
- How high is your fever?
- What symptoms do you have besides?
- Have you recently been abroad, for example in Africa?
- Have you noticed an insect bite?
- Do the people around you have similar symptoms?
Symptoms alone can not diagnose West Nile fever, as the symptoms are very nonspecific and may be caused by other viruses.
In an acute illness with fever and neurological symptoms, however, should also be thought of the West Nile virus as a cause, if the person had previously been in a risk area.
Due to the relationship of the West Nile virus to other viruses, it also leads to false test results more often in the blood test. If it comes in the course of the disease to a central nervous system, the virus can also be detected in cerebrospinal fluid (CSF).
The disease can be detected by direct detection of the virus in the blood by means of a cultural culturing or a so-called PCR (Polymerase Chain Reaction). The latter is a special test method for detecting viruses in the blood.
Since the West Nile virus is very similar to other viruses of the same genus, there is often a likelihood of confusion, for example, with the dengue or yellow fever virus.
The diagnosis of West Nile Fever is not easy for your doctor. This is because the symptoms of West Nile virus can also be similar in many other diseases. These include:
- Flu (influenza)
- Dengue fever
- yellow fever
As already mentioned, the diagnosis of West Nile fever is mainly via a blood test. In this case, either virus components, such as, for example, the viral RNA, or antibodies formed by humans against the virus will be detected in various test methods.
The virus components are only at the beginning of the disease, and the antibodies are detectable only after a few days.
West Nile fever: Treatment
West Nile fever is treated symptomatically. This means that the individual complaints from patients are treated. The cause itself, in this case, the West Nile virus, can not be treated, because there is no drug for this virus yet.
Also, antibiotics do not help, because they only act against bacteria, but not against viruses.
The fever is most effectively treated with antipyretic drugs such as ibuprofen or paracetamol. In addition, calf rolls help to reduce fever.
Rest a lot and give your body time to recover. You should also drink a lot to prevent dehydration.
If you feel sick or you need vomiting, you can take medicines that suppress nausea. These include, for example, dimenhydrinate. You should also eat light food such as rusks or broth.
Patients do not need to be isolated because they are non-infective for others. If the central nervous system is affected or the symptoms are unusually severe, the treatment takes place in a hospital.
Symptoms involving the central nervous system, such as encephalitis, require hospital intensive care treatment, which can quickly respond to potentially fatal complications.
If you have a history of West Nile Fever, your Doctor will send you to a hospital. There, the therapy can be intensified, for example by the administration of fluid via the vein ( infusion ).
How to prevent West Nile Fever?
A special antiviral therapy of the virus does not exist. The treatment of West Nile fever, therefore, focuses on alleviating the symptoms, for example by antipyretic means.
If the illness is severe, it is advisable to have a hospital treatment in order to be able to counteract the complications quickly.
In order to prevent illness of West Nile fever, you should protect yourself in mosquito bites in risk areas. The following helps:
- Wear long clothes!
- Sleep under a mosquito net!
- Provide doors and windows with fly screens!
- Spray yourself and your clothes with repellents (anti-mosquito sprays)!
A vaccine against West Nile fever currently exists only for horses. Although intensive research to develop a vaccine.
Therefore, the best prophylaxis is to protect yourself from the mosquito bites, if you are in a risk area. For this serve long clothes as well as mosquito spray.
At night you should sleep under a mosquito net. There are also mosquito nets for doors and windows. The mosquitoes are active mainly from dawn to dawn.
In some endemic areas, there are programs to curb the spread of virus-transmitting mosquitoes. For this purpose, insecticides are used to destroy mosquito breeding sites. However, these programs often do not have the desired result.