Ticks are important vectors of organisms causing disease in humans. Some common southeastern species are lone star tick, American dog tick, brown dog tick and blacklegged tick. Among the diseases that are transmitted by ticks, Rocky Mountain spotted fever (RMSF), Lyme disease (LD) and ehrlichiosis are the most noted. Symptoms of RMSF include fever, headache and rash. The rash usually develops a few days after infection, around the wrist, ankles and on the back. Initial symptoms feign those of the common flu and many victims often delay going to a physician. A bacteria-like organism called a rickettsia causes RMSF. Not all ticks are infected with the organism but it only takes one infected tick bite to contract it. Lyme disease is caused by a spirochete and is characterized by a distinctive skin lesion in about 65% of the cases. The skin lesion is called erythema migrans (EM) and appears from 3 days to 1 month after the bite (Figure 211). Victims usually suffer with headaches, fever, arthritic-like pain and a stiff neck. Several tick species in the South can transmit RMSF and LD, but the blacklegged tick is most often associated with LD (Figure 212).
A group of biology students from Mercer University in Macon, Georgia have been screening lone star ticks captured from 6 middle Georgia counties for the presence of the causative agents of Lyme Disease and human ehrlichiosis. So far, 17% of the lone star tick population has been infected with Borrelia burgdorferi, the causative agent of Lyme disease and 3% with the causative agent of ehrlichiosis. Human monocytic ehrlichiosis (HME), and human granulocytic ehrlichiosis (HGE) are transmitted by ticks. Both types cause fever, headache, chills, sweating, muscle aches, nausea and vomiting. Antibiotic therapy is effective if started early in the course of infection. The lone star tick is suspected of being the primary vector in the southeastern U.S. Persons working in tick-infested areas should always use a repellent on the outer clothing or at least inspect themselves frequently for ticks. Children should be examined regularly all over after coming in from outside areas. They need to be examined in the scalp and groin areas in particular. Immature ticks are called larvae or “seed ticks” and have only six legs while adults have eight. Both stages are capable of transmitting disease organisms. Ticks should be removed with tweezers or forceps. If parts of the mouth are left in the skin, local irritation can persist for weeks. The mouth is anchored in with barbs and cemented saliva. It is not an easy job to remove an imbedded tick. Unattached ticks can be lifted with adhesive tape. If a tick(s) is found on your body or a family member’s and you feel it has been attached for 6 or more hours, you need to be wary if any flu-like symptoms or rashes appear over the next few days. If so, call your physician and get an examination. Ticks are more likely to vector a disease organism after being attached for 6 or more hours (some experts argue 24 hours, but hey, don’t take a chance). So quick detection and removal is very wise. Children often lose their appetites and are irritable if infected, so be a nosy parent and ask questions and always think tick in the active season. A vaccine has been developed against Lyme disease. LYMErix is a noninfectious vaccine that has been developed by SmithKline Beecham. Persons who habitually encounter ticks should discuss LYMErix with their physician. |
Forest Pests: Insects, Diseases & Other Damage Agents |
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