How do I cure schistosomiasis diseases

Yellow fever

Yellow fever: description

Yellow fever is caused by the yellow fever virus. It is transmitted to humans through the bite of infected mosquitoes. The disease only occurs permanently in certain regions of the world. These are known as yellow fever endemic areas. They are located in (sub) tropical Africa and South America. Travelers traveling to this destination should find out in advance whether a vaccination against yellow fever is required. Asia, Australia, Oceania, North America and Europe are currently considered to be yellow fever free.

The name "yellow fever" comes from the fact that the disease can cause fever and damage the liver in such a way that the skin turns yellow as a result. Because of the liver damage, bilirubin, a yellowish breakdown product of the red blood pigment hemoglobin, can no longer be properly processed in the liver. Instead, it accumulates in the whites of the eyes (sclera) and in the skin, whereupon they turn yellow. This symptom (yellow eyes and skin) is colloquially called jaundice (jaundice). It can occur not only with yellow fever, but also with other diseases that cause liver damage.

Tropical medicine experts estimate that there are around 200,000 yellow fever cases and up to 60,000 deaths worldwide. About 90 percent of these are in Africa. Every suspicion, every illness and every death from yellow fever must be reported. Nevertheless, the World Health Organization (WHO) estimates that there is a high number of unreported cases. This means that even more people may develop yellow fever, but these cases are either not reported or not recognized as such.

There are two forms of yellow fever: that Jungle yellow fever and the City yellow fever. The name depends on where and from whom you are infected.

Jungle yellow fever

The original reservoir of the pathogens (i.e. those organisms in which the viruses normally reside and multiply) are monkeys living in the jungle. Mosquitoes transmit the virus from one monkey to another. If people are in the jungle, there is a risk that they will also be stung and thus become infected with the virus. Because of its origin, this species is known as jungle yellow fever. However, the transmission path from monkey to human causes only isolated infections and mainly affects young men such as forest workers.

City yellow fever

In contrast, there is urban yellow fever. Here, a person suffering from yellow fever is staying with other people. If the vector mosquitoes are still present, they can transmit the yellow fever virus from the sick person to other people. A direct infection from person to person is not possible (or only theoretically through direct blood contact, for example with blood transfusions).

Yellow fever: symptoms

Some infected people develop no symptoms at all. Then doctors speak of one asymptomatic course.

In the remaining cases, it occurs about three to six days after the infection (incubation period) the first symptoms of yellow fever. Usually the disease takes a mild course, which is similar to a flu-like infection. However, some patients are also seriously ill with yellow fever - sometimes with fatal outcome.

Yellow fever: mild course

About 85 percent of those with yellow fever develop flu-like symptoms such as:

This first phase of the disease will Initial phase called. After just a few days, the symptoms slowly subside (Remission phase). In most cases, a full recovery will then occur.

Yellow fever: severe course

In around 15 percent of yellow fever patients, the disease takes a severe course, sometimes after a slight temporary improvement in the symptoms of the initial phase. It comes to toxic phase of the disease. In addition to the symptoms of a mild course, the following yellow fever symptoms can develop:

  • Vomiting bile
  • diarrhea
  • strong thirst and overheated skin on the face and trunk ("red stage")
  • bad breath
  • mild jaundice (jaundice)
  • decreased urine production
  • Bleeding from the palate

In the case of very severe yellow fever, bleeding and damage to the liver and kidneys (“yellow stage”) are in the foreground. The following symptoms can occur:

  • Vomiting like coffee grounds (hematemesis), tarry stools (melena) or bloody diarrhea
  • Skin and mucous membrane bleeding
  • Yellowing of the skin (jaundice) due to acute liver failure
  • acute kidney failure with greatly reduced or absent urine production (oliguria, anuria)
  • Accumulation of toxic metabolic products in the blood (toxemia) as a result of a lack of detoxification by the liver and kidneys
  • Slow heartbeat (bradycardia) - the relative bradycardia with simultaneous fever is called Faget's sign
  • neurological abnormalities such as speech disorders, apathy, convulsions and movement disorders
  • State of shock as a result of high blood and fluid loss (through bleeding, vomiting, diarrhea), characterized by low blood pressure

Due to the various organ bleeding in severe yellow fever, the disease is included in the group of hemorrhagic fever diseases (as well as dengue, Ebola, Lassa fever, etc.). About half of people with this severe form of yellow fever die.

Yellow fever: causes and risk factors

The yellow fever is from Yellow fever virus caused. Like the causative agents of early summer meningoencephalitis (TBE) and dengue fever, it belongs to the genus of Flaviviruses. The yellow fever virus is caused by the bite of certain mosquitoes - mainly the yellow fever mosquito (Aedes aegypti, also called Egyptian tiger mosquito) - transmitted from one host to another. With the jungle yellow fever, animals and humans in Africa get stuck above all over a bite of the mosquito species Aedes africanus on, in South America by a HaemogogusMosquito bite.

A host is an organism whose cells the virus needs in order to multiply. The yellow fever virus is host to both humans and monkeys. The monkeys are part of the virus’s natural reservoir. For many species of monkeys, especially the African ones, an infection with the yellow fever virus is harmless. Only when a mosquito ingests the virus from a monkey with a blood meal and then stings a person does the virus get there (sylvatic or jungle cycle).

If a person is infected, mosquitoes can ingest the virus from them and infect other people (urban or city cycle). This can trigger epidemics.

There is actually only a risk of infection for yellow fever where the mosquitoes occur. A direct infection from person to person, i.e. without the mosquito as a vector, is practically impossible. Only if infected blood (the viruses circulate in the blood from about the 3rd to 6th day after the mosquito bite) would get into the bloodstream of a healthy person (e.g. during a blood transfusion), direct transmission from person to person would theoretically be conceivable.

Yellow fever virus spread throughout the body

When the yellow fever virus gets into the blood through a mosquito bite, it first multiplies in the lymph nodes. It then spreads through the lymph and blood throughout the body. An important organ for the yellow fever virus to multiply is the liver, which can be particularly damaged by the disease. This also explains the common yellowing of the skin and eyes (jaundice). The virus also reaches various other organs such as the kidneys, spleen, bone marrow and muscles. Many organs can be damaged to such an extent that they can no longer work (properly). Doctors then speak of a multiple organ failure that is life-threatening to fatal.

Yellow fever: examinations and diagnosis

The travel history (travel history), fever, bleeding and yellowing of the skin are groundbreaking for the diagnosis of yellow fever. If your doctor suspects you have yellow fever, they will inform you of the Conversation to collect the medical history (Anamnesis) ask the following questions, among others:

  • Have you recently been to another country? If so, which one?
  • When exactly were you there?
  • What did you do there?
  • Do you have pain?
  • Do you have fever?
  • Is your chair colored black?
  • Since when are you having those complaints?

After the conversation one follows physical examination. For example, it will scan your stomach to see if your liver and spleen are enlarged. He will also take a fever and blood pressure. In addition, he removes Blood samples and have them examined in the laboratory. In the case of yellow fever, typical changes such as increased liver values, an accumulation of toxic metabolic products and possibly a coagulation disorder are noticeable. Urine examinations can also show kidney damage, for example through excessive protein excretion (albuminuria).

Insect bites - which really helps

  • Toxic legacy

    Summer, sun, mosquito season: when the little bloodsuckers sting, they leave a little poison behind. The affected area of ​​skin itches like hell, swells and hurts. This also applies to stings and bites from other insects. This is how you can alleviate the agonizing symptoms.
  • Cold and acid

    The first measure: cooling! With frozen ice cubes or cold water flowing from every tap. Then it's best to grab a lemon or onion from the fruit and vegetable basket, cut it open and place it on the puncture site. The ingredients soothe itching, reduce swelling and inhibit possible bacterial inflammation. Vinegar is believed to have a similar effect.
  • Beneficial plant

    With a little luck you will find the right antidote to insect bites in the grass next to you - ribwort. It is best to pluck a few leaves from the green plant with white flowers and rub them between your fingers. Or you can chew the leaves in your mouth. Put the pulp on the puncture site.
  • Gel and ointment

    Not every healing plant can simply be picked along the way. But you are sure to find what you are looking for in the pharmacy or drugstore: arnica ointment or aloe vera gel have anti-inflammatory and germ-inhibiting effects. Aloe vera gel also has a cooling effect.
  • Natural oils

    Nature has even more in store for you: Various oils can cool the reddened area, relieve itching and prevent inflammation. Tea tree oil, lavender oil, and clove oil are some examples of natural oils that help against insecticide. Put a few tropics on a cotton ball and use them to dab the bite and sting of the tormentors.
  • Healing heat

    Thermo stitch healer - have you heard of it? It's a small plastic pen with a gold plate on top. It transfers heat and is supposed to neutralize the poison. If you have such a pen, you should press it down on the puncture site for a few seconds as quickly as possible. Don't worry: you won't get any scars because the pen only generates a temperature of around 50 degrees Celsius.
  • Medical help

    If the sting continues to swell, feel sick, or develop breathing difficulties, you must see a doctor immediately! It could be a severe allergic reaction. The doctor can prescribe antiallergic medication to prevent worse from happening. You should also seek medical treatment if the sting becomes infected.
  • By Dr Varinka Voigt

Evidence of yellow fever infection

It can be difficult to diagnose yellow fever. This is mainly due to the unspecific, flu-like symptoms at the beginning of the illness. Bleeding and organ damage can also occur in other diseases. Yellow fever, for example, must be distinguished from malaria, typhus, dengue fever, Ebola, Lassa fever and hepatitis B and D. For a reliable diagnosis it is therefore necessary to detect either the yellow fever virus itself or specific antibodies against it in the patient's body:

After the first two to five days of the disease, a so-called Polymerase chain reaction (PCR) the genetic material of the yellow fever virus (RNA virus) can be detected in the blood. From about the fifth to seventh day of the disease, the patient has specific antibody formed against the yellow fever virus. These can also be made visible in the blood (serological examination).

Yellow fever: treatment

So far there is no specific therapy for yellow fever - there are no drugs or other therapies that can directly fight the yellow fever virus. So the disease can only symptomatic be treated. This means that one can only alleviate the signs of the disease.

A therapy with interferon alpha is currently being researched. It is showing initial success with infected monkeys.

Symptomatic treatment

First and foremost, fluid losses are compensated for with infusions, and the fever is lowered with fever medication such as paracetamol. If the patient is so weakened as a result of yellow fever that he also develops a bacterial infection, this can be treated with antibiotics.

Especially when the disease is severe, patients need one Intensive care unit are cared for. In a yellow fever endemic area where the Egyptian tiger mosquito is present, the patient must be isolated. In this quarantine it cannot be bitten by mosquitoes, so that they cannot transmit the virus to other people.

Yellow fever: vaccination

How to prevent yellow fever with a vaccination, read in the article yellow fever vaccination.

Yellow fever: disease course and prognosis

If symptoms occur at all after infection, yellow fever is mild in most cases (85 percent) and is over after a few days. Of the approximately 15 percent of patients who develop yellow fever seriously, around every second person dies - even if maximum intensive medical care is used. Measured against all yellow fever infections, around 10 to 20 percent of those affected die.

Those who survive the disease usually recover completely. Sometimes, however, patients complain of severe tiredness (fatigue) that can last for several weeks.

Experts suspect that if you have survived a yellow fever infection, you will likely be immune to yellow fever for life due to the antibodies that are formed.

Prevent yellow fever

As there is no specific treatment and yellow fever is potentially life threatening, vaccination is very important. Some African and South American countries make vaccination mandatory on entry and exit (and, if applicable, transit). An epidemic spread can only be prevented if the majority (60 to 90 percent) of the people in an area are vaccinated against yellow fever.

In addition to vaccination, great importance should also be attached to mosquito protection. It should be noted that the yellow fever mosquitoes are predominantly diurnal, but also nocturnal. Therefore, protection from mosquito pieces around the clock is necessary. Special mosquito repellants ("repellents") suitable for the tropics and wearing long, light-colored clothing help. An impregnated mosquito net protects against the bloodsuckers at night. Preventing mosquito bites is critical to tropical diseases like the Yellow fever to prevent.

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