Pathophysiology: Ehrlichiosis is a bacterial illness transmitted by ticks that causes flu-like symptoms. The signs and symptoms of ehrlichiosis range from mild body aches to severe fever and usually appear within a week or two of a tick bite. If treated quickly with appropriate antibiotics, ehrlichiosis generally improves within a few days. Another tick-borne infection — anaplasmosis — is closely related to ehrlichiosis. But the two have distinct differences and are caused by different microorganisms. Ehrlichiosis is caused by ehrlichia bacteria and is transmitted primarily by the Lone Star tick.Ticks feed on blood, latching onto a host and feeding until they're swollen to many times their normal size. During feeding, ticks that carry disease-producing bacteria can transmit the bacteria to a healthy host. Or they may pick up bacteria themselves if the host, such as a white-tailed deer or a coyote, is infected. If a tick carrying the bacterium that causes ehrlichiosis has been feeding on you for at least 24 hours, the following flu-like signs and symptoms may appear — usually within seven to 14 days of the bite: • Mild fever • Headache • Chills • Muscle aches • Nausea • Vomiting • Diarrhea • Fatigue • Loss of appetite • Joint pain • Confusion • Rash • Cough Statistics: Tick-associated febrile illness was prospectively studied in Southeast Sweden in order to assess the occurrence of human granulocytic ehrlichiosis (HGE). Inclusion criteria were fever (> or = 38.0 degrees C), with or without headache, myalgia or arthralgia in patients with an observed tick bite or tick exposure within 1 month prior to onset of symptoms. Patients with clinical signs of Lyme borreliosis were included. Of the 27 patients included, we identified 4 cases of HGE. Three of the patients had coinfection with Lyme borreliosis, which presented as erythema migrans. All 27 patients presented with a 2-5 d history of fever. None of the clinical signs or laboratory parameters monitored was helpful in predicting ehrlichiosis in this group with tick-associated fever conditions. Within the HGE-negative group (n = 23), 12 patients had clinical or laboratory signs of Lyme borreliosis. For 11 patients, the aetiology of the fever remained unclear. Our results suggest that HGE is common in tick-infested areas of Southeast Sweden, and may occur as a coinfection of Lyme borreliosis. Granulocytic ehrlichiosis should be suspected in patients who present with tick-associated fever, with or without erythema migrans. Ehrlichia serology and PCR should be employed to confirm the diagnosis.
Ehrlichiosis is reported more frequently in adults than in children. The highest age range is between 40 and 64 years. Treatment: Doxycycline is the first line treatment for adults and children of all ages and should be initiated immediately whenever ehrlichiosis is suspected. Use of antibiotics other than doxycycline and other tetracyclines is associated with a higher risk of fatal outcome for some rickettsial infections. Doxycycline is most effective at preventing severe complications from developing if it is started early in the course of disease. Therefore, treatment must be based on clinical suspicion alone and should always begin before laboratory results return. If the patient is treated within the first 5 days of the disease, fever generally subsides within 24-72 hours. In fact, failure to respond to doxycycline suggests that the patient’s condition might not be due to ehrlichiosis. Severely ill patients may require longer periods before their fever resolves. Resistance to doxcycline or relapses in symptoms after the completion of the recommended course have not been documented. Recommended Dosage Doxycycline is the first line treatment for adults and children of all ages: • Adults: 100 mg every 12 hours • Children under 45 kg (100 lbs): 2.2 mg/kg body weight given twice a day Patients should be treated for at least 3 days after the fever subsides and until there is evidence of clinical improvement. Standard duration of treatment is 7 to 14 days. Some patients may continue to experience headache, weakness and malaise for weeks after adequate treatment.