A pathogen is a biological agent, or germ, that causes disease to its host by interrupting normal body processes. Bacteria, viruses, fungi and parasites are all common types of pathogens that can cause pathogenic, or infectious, diseases. These pathogens can be found in the air, soil and water, and infection can occur as a result of touching, eating or drinking something that is infected with a germ. Pathogenic diseases are the leading cause of death worldwide, according to Medline Plus.
Trichinellosis, also called trichinosis, is an infection caused by eating raw or undercooked meat that is infected with the larvae of the worm Trichinella. Trichinella is most often found in wild animals that eat meat, but may also be found in domestic pigs, according to the Centers for Disease Control and Prevention. Initial symptoms of trichinellosis include nausea, diarrhea, fatigue, vomiting, fever and abdominal pain. As the infection progresses, more serious symptoms, such as headache, chills, cough, muscle ache and pain and itchy skin, may develop. Severe cases of trichinellosis cause heart problems, breathing difficulties and an inability to control muscle movement. These severe cases can result in death. Trichinellosis is treated with a series of medications.
Cellulitis is a skin infection caused by the bacteria streptococcus or staphylococcus. Most commonly, the bacteria enter the body through a wound or open area on the skin, but can also gain access to the body through an insect bite. Cellulitis can occur anywhere on the body, but is most often seen on the lower leg, according to Mayo Clinic. Symptoms of cellulitis include redness, swelling, tenderness, pain, warm skin and fever. Treatment of cellulitis consists of an oral antibiotic that must be taken for 14 days. If left untreated, cellulitis can spread and cause a life-threatening infection in the body.
Lyme disease is an inflammatory disease caused by the bacterium Borrelia burgdorferi. Borrelia burgdorferi is carried by certain types of ticks that obtain the bacteria through biting infected mice or deer. Humans acquire Lyme disease when they are bitten by an infected tick. New cases of Lyme disease are most often seen in late spring, summer and early fall when ticks are most abundant, according to Medline Plus. The disease is usually detected through the presence of a bull's-eye shaped rash at the infection site. Initial symptoms of Lyme disease include chills, fever, headache, muscle pain and weariness. As the disease progresses, itching, joint inflammation, a stiff neck and abnormal behavior may occur. Antibiotics are used to treat Lyme disease. In cases where joint inflammation and stiffness is severe, anti-inflammatory medications may be prescribed.