Signs and tests

Anthrax

Anthrax is an infectious disease due to a type of bacteria called Bacillus anthracis. Infection in humans most often involves the skin, gastrointestinal tract, or lungs.

Causes, incidence, and risk factors

Anthrax commonly affects hoofed animals such as sheep, cattle, and goats, but humans who come into contact with infected animals can get sick from anthrax, too. In the past, the people who were most at risk for anthrax included farm workers, veterinarians, and tannery and wool workers.

There are three main routes of anthrax infection:

- Cutaneous anthrax occurs when anthrax spores touch a cut or scrape on the skin.

* It is the most common type of anthrax infection.

* The main risk is contact with animal hides or hair, bone products, and wool, or with infected animals. People most at risk for cutaneous anthrax include farm workers, veterinarians, and tannery and wool workers.

- Inhalation anthrax develops when anthrax spores enter the lungs through the respiratory tract. It is most commonly contracted when workers breathe in airborne anthrax spores during processes such as tanning hides and processing wool.

Breathing in spores means a person has been exposed to anthrax, but it does not mean the person will have symptoms.

* The bacteria spores must "germinate" or sprout (the same way a seed might sprout before a plant grows) before the actual disease occurs. The process usually takes 1 to 6 days. Forty-three days is the longest known incubation period.

* Once the spores germinate, they release several toxic substances. These substances cause internal bleeding, swelling, and tissue death.

- Gastrointestinal anthrax occurs when someone eats anthrax-tainted meat.

Anthrax may be used as a biological weapon or for bioterrorism. In 2001, anthrax sent through the U.S. Postal Service infected 22 people; 7 survivors had confirmed cutaneous anthrax disease.

Symptoms

Symptoms of anthrax differ depending on the type of anthrax.

Symptoms of cutaneous anthrax start 1 to 7 days after exposure:

* An itchy sore develops that is similar to an insect bite. This sore may blister and form a black ulcer (sore).

* The sore is usually painless, but it is often surrounded by swelling.

* A scab often forms, and then dries and falls off within 2 weeks. Complete healing can take longer.

Symptoms of inhalation anthrax:

* Begins with fever, malaise, headache, cough, shortness of breath, and chest pain

* Fever and shock may occur later

Symptoms of gastrointestinal anthrax usually occur within 1 week and may include:

* Abdominal pain

* Bloody diarrhea

* Fever

* Mouth sores

* Nausea and vomiting (the vomit may contain blood)

Signs and tests

The tests to diagnose anthrax depend on the type of disease that is suspected.

A culture of the skin, and maybe a biopsy, are done on the skin sores. The sample is looked at under a microscope to identify the anthrax germ.

Tests may include:

* Blood culture

* Chest CT scan or chest x-ray

* Spinal tap to check for infection around the spinal column

* Sputum culture

Fluid or blood samples may be sent to a special laboratory for more testing, including PCR, immunofluorescence, and immunohistochemistry.

Treatment

Most people with anthrax are treated with antibiotics. Several antibiotics are effective, including penicillin, doxycycline, and ciprofloxacin.

Expectations (prognosis)

When treated with antibiotics, cutaneous anthrax is likely to get better. But in most cases anthrax infection results in death.

Prevention

There are two main ways to prevent anthrax.

For people who have been exposed to anthrax (but have no symptoms of the disease), doctors may prescribe preventive antibiotics, such as ciprofloxacin, penicillin, or doxycycline, depending on the strain of anthrax.

An anthrax vaccine is available to military personnel and some members of the general public. It is given in a series of five doses over 18 months.

TBE (tick-borne encephalitis)

Tick-borne encephalitis (TBE) is a viral infection of the central nervous system (brain and spinal cord) that is spread by tiny blood-sucking parasites called ticks.

TBE can cause encephalitis (inflammation of the brain), meningitis (inflammation of the membranes that surround the brain and spinal cord) and other serious problems with the nervous system.

The TBE virus is found naturally in small animals such as mice and voles and in domestic animals such as sheep, goats and cattle. Ticks are the main carriers of the virus, picking up the virus when they feed on the blood of an infected animal. Once the tick is infected with the virus, it carries this for life.

Humans become infected with TBE when they are bitten by an infected tick. The virus is present in the tick’s saliva, which contains a natural anaesthetic, so you may not notice you have been bitten. It is important to check your body regularly for ticks when in risk areas.

Ticks live in forests, grasslands, riverside meadows, marshes, brushwood and shrublands. They usually live in the undergrowth, where they can easily get onto the clothes or skin of passers-by.

Tick activity depends on factors such as temperature, moisture and humidity. Wet summers and mild winters increase tick activity. In central Europe the main periods of tick activity are May/June and September/October.

The initial symptoms of TBE usually occur 7–14 days after a tick bite. The main symptoms are fever, headache, flu-like symptoms, tiredness, muscular pain and nausea.

These first-stage symptoms usually last between one and eight days. After this, there are no symptoms for the following 1–20 days. Around one-third of those who experience first-stage symptoms go on to develop the second phase of the disease.

The second stage of the disease starts with a sudden rise in temperature. The virus starts to affect central nervous system, which can result in meningitis and encephalitis. These conditions can cause paralysis.

To diagnose the disease it is necessary to take blood analyses for antibodies to the virus. Commonly an MRI scan and a lumbar puncture are prescribed.

Paracetamol can be taken to relieve any flu-like symptoms.

In cases of stage-two TBE, there is no specific drug treatment. For severe symptoms such as meningitis and encephalitis, you need to go to hospital where you will be given supportive treatments such as intravenous fluids, help with breathing and nursing care to support your body while you recover.

A vaccination is the best way to prevent TBE for people living, working or travelling in risk countries. You may consider having the TBE vaccination if:

The best time to start a course of TBE vaccination is during the winter months to make sure you are protected before the start of the tick season in spring.

The TBE vaccine is usually given in three doses, with the second dose given one to three months after the first dose, and the third dose given five and 12 months after the second dose.

The best way to lower your risk of TBE is to avoid tick bites as much as possible when in risk areas:

* Wear long-sleeved tops and long trousers (tucked into socks). You can treat your clothes with insecticides such as permethrin.

* Apply insect repellent containing DEET to any exposed skin.

* Check your body for ticks regularly. Common places to find them are the hair line, behind the ears, elbows, backs of knees, the groin and armpits.

* Avoid eating and drinking milk and unpasteurised dairy products in countries where there is a high risk of TBE.

What to do if you find a tick

After a tick has attached itself to you, it may not start feeding for several hours. Adult ticks, once they have fed, can be up to the size of a coffee bean, but tick larvae can be tiny.

If you find a tick on your body, you should remove it as quickly as possible with a pair of tweezers or tick remover:

* Place the tweezers as close as possible to your skin and pull the tick off very firmly and slowly until the tick lets go of your skin (make sure you remove its head and mouth).

* Avoid squeezing the body of the tick and the contents of its stomach into the site of your bite.

* After you have removed the tick, wash your hands and the affected area with soap and water.

Дата добавления: 2015-11-14