Mary D. Nettleman, MD, MS, MACP is the Chair of the Department of Medicine at Michigan State University. She is a graduate of Vanderbilt Medical School, and completed her residency in Internal Medicine and a fellowship in Infectious Diseases at Indiana University.
Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
Tularemia is an infection caused by the Gram-negative
bacteria Francisella tularensis. The organism is named after Edward Francis who,
while in Tulare County, Calif., helped discover how the disease was spread and how
the organism could be cultured.
Tularemia is usually a disease of animals. Humans can acquire tularemia when
they come in contact with infected animals or are bitten by insects that have
fed on an infected animal. Ticks, biting flies, and mosquitoes have been shown
to transmit tularemia between animals and humans. Tularemia is one of several
tick-borne diseases and can be spread by many species of ticks, including
Dermacentor variabilis and Amblyomma americana. Among biting flies, the deer fly
(Chrysops spp.) is the most widely cited vector. Even small doses of these
bacteria (10-50 bacteria) have the potential to cause severe disease. For this
reason, F. tularensis has the potential to be used as a bioweapon.
What are the different types of tularemia?
There are four subspecies of F.
tularensis, and all are capable of causing disease in humans (F. tularensis, F. holarctica, F. mediasiatica, and F. novicida). The subspecies
tularensis and holarctica are the most common causes of tularemia in humans. The type of
tularemia depends on which subspecies is involved and how the organism was
acquired. Disease caused by the subspecies F. holarctica is often
milder than that caused by F. tularensis.
The type of disease is often named for the most prominent symptoms. Thus,
ulceroglandular tularemia is usually caused by inoculation of the skin and is
associated with open sores and swollen lymph nodes. If there is no sore but
swollen lymph nodes are prominent, the disease may be classified as glandular.
If the eye or throat is involved, oculoglandular or pharyngeal tularemia is
said to be present. Disease involving the lungs is termed pneumonic disease.
Tularemia that predominately affects the bloodstream and body organs is referred
to as typhoidal tularemia.
The word "rash" means an outbreak of red bumps on the body. The way people use this term, "a rash" can refer to many different skin conditions. The most common of these are scaly patches of skin and red, itchy bumps or patches all over the place.
Pneumonia is inflammation of one or both lungs with consolidation. Pneumonia is frequently but not always due to infection. The infection may be bacterial, viral, fungal or parasitic. Symptoms may include fever, chills, cough with sputum production, chest pain, and shortness of breath.
Most sore throats are caused by viruses or mechanical causes (such as mouth breathing) and can be treated successfully at home. However, a person should be seen by a health care professional if they have a sore throat that has a rapid onset, and is associated with a fever or tenderness of the front of the neck; a sore throat that causes the person to have difficulty swallowing (not just pain swallowing) or breathing; or if a sore throat lasts for more than a week.
Diarrhea is a change is the frequency and looseness of bowel movements. Cramping, abdominal pain, and the sensation of rectal urgency are all symptoms of diarrhea. Absorbents and anti-motility medications are used to treat diarrhea.
Headaches can be divided into two categories: primary headaches and secondary headaches. Migraine headaches, tension headaches, and cluster headaches are considered primary headaches. Secondary headaches are caused by disease. Headache symptoms vary with the headache type. Over-the-counter pain relievers provide short-term relief for most headaches.
Lymph nodes help the body's immune system fight infections. Causes of swollen lymph nodes (glands) may include infection (viral, bacterial, fungal, parasites). Symptoms of swollen lymph nodes vary greatly. They can sometimes be tender, painful or disfiguring. The treatment of swollen lymph nodes depends upon the cause.
Jaundice is a yellowish staining of the skin and whites of the eyes (sclerae) with bilirubin, the pigment found in bile. Jaundice can be an indicator of liver or gallbladder disease, or it may result from the rupture of red blood cells (hemolysis).
Although a fever technically is any body temperature above the normal of 98.6 degrees F. (37 degrees C.), in practice a person is usually not considered to have a significant fever until the temperature is above 100.4 degrees F (38 degrees C.). Fever is part of the body's own disease-fighting arsenal: rising body temperatures apparently are capable of killing off many disease- producing organisms.
The spleen enlarges if it is asked to do excessive work in filtering or manufacturing blood cells, if there is abnormal blood flow to it, or if it is invaded with abnormal cells or deposits. Symptoms of an enlarged spleen may include weakness and fatigue, easy bleeding, and poor white blood cell function. Treatment of an enlarged spleen is focused toward the cause of the splenomegaly. Surgery may be required to remove the spleen.
Osteomyelitis is an infection of the bone. Potential causes include injections around the bone, fractures that puncture the skin, recent surgeries, and bacterial infections that travel from other areas of the body, spreading through the blood to the bone. Symptoms include pain, fever, chills, stiffness, and nausea. Treatment involves antibiotics and pain medications. Surgery is sometimes necessary.
Encephalitis is a brain inflammation that causes sudden fever, vomiting, headache, light sensitivity, stiff neck and back, drowsiness, and irritability. Meningitis is an infection that causes inflammation of the meninges that surround the brain and spinal cord. Symptoms of meningitis include high fever, headache, nausea, vomiting, and stiff neck.
Ticks are known transmitters of disease to humans and animals. Tick-borne diseases include Lyme disease, Rocky Mountain spotted fever, Q fever, tularemia, babesiosis, and Southern tick-associated rash illness. Infected ticks spread disease once they've bitten a host, allowing the pathogens in their saliva and mouth get into the host's skin and blood. Tick bites are typically painless, but the site of the bite may later itch, burn, turn red, and feel painful. Individuals allergic to tick bites may develop a rash, swelling, shortness of breath, numbness, or paralysis. Tick bite treatment involves cleaning and applying antibiotic cream.
Bioterrorism is a form of terrorism where there is the intentional release of biological agents such as viruses, germs, or bacteria. Diseases caused by bioterrorism agents include anthrax, botulism, plague, smallpox, tularemia, brucellosis, food poisoning, Q fever, ricin toxin poisoning, cholera, epidemic typhus, viral encephalitis, XDR TB, and MDR TB.
Ticks are scientifically classified as Arachnida (which includes spiders). The
fossil record suggests ticks have been around at least 90 million years. There
are over 800 species of ticks throughout the world, but only two families of
ticks, Ixodidae (hard ticks) and Argasidae (soft ticks), are known to transmit
diseases or illness to humans. Hard ticks have a scutum, or hard plate, on their
back while soft ticks do not.
Ticks have a complex life cycle that includes eggs, larvae, nymphs, and adult
male and female ticks. The larvae, nymphs, and adults all need blood meals.
Usually, the female adult (hard tick) is the one causing the most bites as males
usually die after mating. Ticks do not jump or fly. They simply reach out with
their legs and grab or crawl onto a host. Although some larvae have preferred
hosts, most ticks in the nymph or adult phase will attach a get a blood meal
from several different kinds of anim...