Anthrax is contracted primarily through exposure to spores of the bacterium *Bacillus anthracis*, which can survive in the environment, especially soil, for many years. The ways people become infected depend on the route by which these spores enter the body, leading to different forms of the disease.
The most common way anthrax is contracted is through **direct contact with infected animals or animal products**. This usually happens when people handle the hides, wool, hair, or meat of animals that carry the bacteria. For example, farmers, veterinarians, or workers in industries processing animal products may come into contact with spores on the skin or through small cuts or abrasions. This contact causes **cutaneous anthrax**, the most frequent form, which starts as a small bump or pimple that quickly develops into a painless ulcer with a characteristic black center, often called a malignant pustule. The infection is usually localized to the skin but can spread if untreated.
Another route is **inhalation of anthrax spores**, which occurs when spores become airborne and are breathed in. This form, known as **inhalational anthrax** or “woolsorters’ disease,” is more dangerous and can happen in places where animal products like wool, hair, or hides are processed and spores are released into the air. Inhaled spores travel to the lungs and lymph nodes, causing severe respiratory illness that can progress rapidly to fatal pneumonia if not treated promptly.
A third way anthrax can be contracted is through **ingestion of contaminated meat** from infected animals, leading to **intestinal anthrax**. This form affects the digestive tract, causing symptoms like vomiting, severe diarrhea, abdominal pain, and fever. It is less common but can occur in regions where people consume meat from animals that died of anthrax.
There is also a less common form called **injection anthrax**, which has been reported in people who inject illegal drugs contaminated with anthrax spores. This form can cause severe soft tissue infections and systemic illness.
Anthrax spores are highly resilient; they can survive harsh conditions such as heat, drought, and disinfectants for long periods in soil. This environmental persistence means that outbreaks can occur when spores are disturbed and come into contact with animals or humans. Animals grazing on contaminated pastures can become infected, and humans can contract anthrax by handling these animals or their products.
In rare cases, insect bites from flies that have fed on infected animals may also transmit anthrax, although this is not a common route.
Because anthrax is a zoonotic disease—transmitted from animals to humans—its occurrence is closely linked to animal outbreaks. Preventive measures include vaccination of livestock, avoiding contact with infected animals or their products, and using protective clothing and respirators in high-risk occupations. Proper sterilization and sanitation in industries handling animal materials also reduce the risk of inhalational anthrax.
Once anthrax spores enter the body, they can germinate and multiply, producing toxins that cause tissue damage and severe illness. The severity and symptoms depend on the route of infection, but early diagnosis and treatment with antibiotics are critical to prevent serious outcomes.
In summary, anthrax is contracted mainly by:
– **Skin contact** with infected animals or animal products, causing cutaneous anthrax.
– **Inhalation** of airborne spores, causing inhalational anthrax.
– **Eating** meat from infected animals, causing intestinal anthrax.
– **Injection** of contaminated drugs, causing injection anthrax.
– Occasionally, through **insect bites** from flies that have contacted infected animals.
The disease is rare in humans but remains a concern in areas where animal anthrax is endemic or where animal products are handled without adequate precautions.
