Tick-bite fever caused by Rickettsia rickettsii occurs mainly in North and South America, but there in all countries of the double continent. Therefore, the names American tick-bite fever, Rocky Mountain spotted fever, Colombian Tobia fever, Sao Paulo fever, or New World fever are also found.
What is tick-bite fever caused by Rickettsia rickettsii?
A tick bite or tick bite can transmit various diseases into the host organism. The best known of these is Lyme disease. However, other diseases are also possible from ticks in other countries. Ticks are a type of mite which, as blood-sucking parasites, can transmit dangerous germs to all vertebrates. Rickettsiae are tick-borne bacteria named after U.S. pathologist Howard Taylor Ricketts, who identified the bacterial species in 1907. Tick-bite fever caused by Rickettsia rickettsii belongs to the group of rickettsioses, which includes all diseases caused by Rickettsia bacteria. Rickettsiae are transmitted not only by ticks but also by other mite species and by lice and fleas. Rickettsioses include tick-bite fever caused by Rickettsia rickettsii as well as spotted fever diseases. The diseases mostly occur in the spring and summer months. Approximately 2 people are infected per million inhabitants in the USA each year. Most of those infected live in rural areas. Tick-bite fever caused by Rickettsia rickettsii disproportionately affects men 40 years of age and older and children up to 10 years of age.
Causes
Tick-bite fever caused by Rickettsia rickettsii results from infection with a special type of Rickettsia bacteria. The bacteria can survive only inside a host cell. They are mainly found in the intestinal cells of ticks, for example. In dry conditions or when disinfectants are used, the bacteria quickly perish. Rickettsiae also do not survive in artificially produced nutrient solutions. However, rickettsiae can survive for a long time in excretions, e.g. of lice, and therefore remain infectious for months. Once the bacteria have been transmitted into the human body by a tick bite, they multiply in the host cells by continuous transverse division. They then spread within the body via lymphatic vessels and blood vessels. The symptoms of tick-bite fever caused by Rickettsia rickettsii are triggered by the destruction of body cells caused by the bacteria.
Symptoms, complaints, and signs
Tick-bite fever caused by Rickettsia rickettsii is a very serious disease, which can be completely cured only by the intervention of quick medical help. Particularly in children under ten years of age, in immunocompromised persons, or if treatment is delayed, the disease, which only occurs in America, can take a life-threatening course. Initially, after an incubation period of two to fourteen days, nonspecific flu-like symptoms appear. The sufferer complains of headache, high fever, aching limbs, abdominal pain, nausea, vomiting, loss of appetite, reddened eyes and muscle aches. After another two to five days, an extensive skin rash appears. This exanthema is characterized by small red spots alternating with raised papules. Small hemorrhages are possible from the papules. Otherwise, the rash is not associated with any symptoms. However, a variety of complications can occur in the further course, which do not occur in the same way in every person. Thus, for the individual, the combination of symptoms that occurs cannot be predicted. However, such symptoms as sudden severe drop in blood pressure, palpitations, blood clotting disorders, jaundice (icterus), acute renal failure, shock or neurological disorders are observed. Acute kidney failure, sudden onset of blood pressure drop, or cardiac arrhythmias can quickly lead to death. In other cases, serious long-term damage sets in, including death of fingers and toes, paralysis, deafness, or blindness.
Diagnosis and progression
Although infection with tick-bite fever caused by Rickettsia rickettsii is difficult to diagnose in the early stages of the disease, because suitable testing methods are not available for this initial period.Nevertheless, the disease must be treated as early as possible. The first indications of a possible tick bite can be obtained by questioning the patient about his living environment, his travel habits and the seasonal onset of his symptoms. Only at a later stage can a definite diagnosis of the presence of tick-bite fever caused by Rickettsia rickettsii be made by examination of the skin tissue or by blood tests and by selective multiplication of rickettsiae in blood cultures. Tick-bite fever caused by Rickettsia rickettsii is a serious, although curable, disease. Without treatment, the disease is fatal in about 30% of cases. However, if the affected person survives the first days of illness, there is usually a complete cure. Tick-bite fever caused by Rickettsia rickettsii takes a more severe course in children up to 3 years of age and in males in general. In these cases, complications such as significant circulatory disturbances or renal failure can quickly cause death. Possible late effects of tick-bite fever caused by Rickettsia rickettsii include paralysis or loss of hearing.
Complications
Tick-bite fever caused by Rickettsia rickettsii is often a very severe disease, but it has a good chance of recovery if treated promptly. As a rule, the infection then heals completely. However, the course of the infection and possible complications depend on the time when treatment is started and on the constitution of the people affected. For example, children under ten years of age and immunocompromised individuals in particular often suffer severe complications that can be fatal or lead to chronic long-term damage. The start of treatment is also crucial for the chances of recovery. If treatment is started too late, about five days after the onset of infection, fatal complications can occur even in previously healthy people. However, if treatment begins immediately, almost all those affected survive. In the acute phase, for example, the occurrence of circulatory shock, palpitations and kidney failure are possible without timely therapy. Death then often occurs within a very short time. In a few cases, there may be long-term consequences such as paralysis, deafness, blindness or tissue necrosis of fingers and toes. However, this usually only affects people with a weakened immune system, children under the age of ten, alcohol abusers, or people deficient in the enzyme glucose-6-phosphate dehydrogenase. Patients who survive the severe complications in the acute phase of the infection, however, may still suffer chronic heart or kidney disease as long-term consequences.
When should you see a doctor?
A doctor is not always needed for the bite of a tick. If the affected person feels able to remove the tick completely from the organism, he can heal himself with a few simple steps. If the patient is free of symptoms within the next few days, no further measures need to be taken. Tick-bite fever occurs on the American continent. If health problems occur immediately after the tick bite, action is required. A doctor should be consulted if symptoms such as headache, vomiting, nausea, pain in the limbs or abdominal pain occur. If there is a loss of appetite or if there are irregularities in the muscular system, a visit to the doctor is necessary. In case of changes in the skin appearance, disturbances of the heart rhythm, signs of paralysis as well as high fever, medical care should be initiated immediately. In acute cases, an ambulance service should be alerted. If there are disturbances of sensibility or if the physical performance decreases, the affected person needs medical help. Numbness in fingers or toes is characteristic of the disease. A doctor should therefore be consulted at the very first signs of the above-mentioned health discrepancies. Since the disease can lead to serious complications if left untreated, action should be taken as soon as possible in the event of a general deterioration of health.
Treatment and therapy
Of particular importance is the earliest possible treatment of tick-bite fever caused by Rickettsia rickettsii. If therapy does not begin by the fifth day after the onset of illness, an unfavorable course of disease is predicted. If tick-bite fever caused by Rickettsia rickettsii is suspected, treatment should be given in a hospital if possible.The disease can be cured in most cases by administration of antibiotics. Antibiotics suitable for the treatment of tick-bite fever caused by Rickettsia rickettsii are the so-called tetracyclines, which lead to an inhibition of protein production and growth of the rickettsia. However, tetracyclines should not be administered to pregnant women and children because the active ingredient can be deposited in bones and teeth and lead to increased susceptibility to tooth decay and an increased incidence of bone fractures. Another very effective antibiotic is chloramphenicol. This is a broad-spectrum antibiotic, but because of possible side effects, it should only be used when tick-bite fever caused by Rickettsia rickettsii cannot be controlled in any other way. Both preparations are administered intravenously to the body. In addition to antibiotic treatment alone, which directly targets the Rickettsia bacteria, adjunctive therapies may be needed to provide relief from the symptoms of tick-bite fever caused by Rickettsia rickettsii. Administration of analgesics may be appropriate. In some patients, an infusion may need to be done to provide fluids to the person suffering from tick-bite fever caused by Rickettsia rickettsii.
Prevention
There are no commonly available vaccines against tick-bite fever caused by Rickettsia rickettsii. The only possible prevention is to avoid tick bites. Anyone who spends time in the high-risk areas of North and South America should check their body regularly for ticks. Outdoors, clothing should cover the body as much as possible. This includes wearing long pants, long-sleeved upper body clothing, and a head covering. This will at least make it more difficult for ticks to nest and for Rickettsia rickettsii to infect the body with tick-bite fever.
Aftercare
If tick-bite fever caused by Rickettsia rickettsii has been detected early and has healed completely, tick-bite fever usually does not cause any sequelae. Nevertheless, regular follow-up examinations should take place in the first period after the disease to check the blood for Rickettsia rickettsii. If pathogens are detected again, antibiotic therapy must be repeated. After successful treatment of tick-bite fever caused by Rickettsia rickettsii, alcohol consumption should also be completely avoided for two to four weeks, as this often causes complications and late effects in persons suffering from tick-bite fever. In addition to this, regular neurological follow-up should take place, as tick-bite fever caused by Rickettsia rickettsii can in some cases cause nerve diseases as long-term consequences. If paralysis, numbness or tingling of the body or extremities occurs during the course of life without a cause being identified, a doctor should be consulted and informed immediately. In this case, a neurological diagnosis and treatment must be carried out, as these are not only late symptoms of tick-bite fever, but can also be symptoms of a stroke. If paralysis or numbness develop as a result of tick-bite fever, these must be treated with medication (pain therapy) and physiotherapy. Appropriate therapy must be intensively discussed with and monitored by the attending neurologist.
What you can do yourself
When bitten by a tick, the affected person should be able to assess his own competencies well. If he does not have the sufficient knowledge of how to remove a tick correctly, the help of people from the social environment or medical professionals should generally be sought. Regardless of whether the tick bite occurs in domestic regions or while traveling in American areas, the procedure for removing the insect bite is the same. During the whole procedure, it is important to have a steady hand and not to make any frantic movements. If, despite all efforts and a professional approach, complications occurred during a self-initiated removal of the insect, a doctor should be consulted immediately. If residues of the insect body can be seen or felt in the organism, medical help is needed. The affected person should not expose himself to physical overexertion and should keep a close watch on further health developments and his own well-being.Sufficient fluids should be taken in and the existing wound should be treated sterilely. Rest and sparing are particularly important for the regeneration process. However, the possibilities of self-help reach their limits as soon as there is a deterioration in health. General dysfunction, pain, or fever can no longer be adequately cared for on their own.
