Types and symptoms of typhus
Typhus is an infectious disease caused by Rickettsia bacteria and characterized by fever, rash, and delirium. The term derives from the Greek word meaning smoky or hazy, which describes the state of consciousness of affected people.
Historically typhus is known as one of the main causes of mortality during wars, famines, and other natural disasters.
The term typhus may be referred to one of the forms of this disease:
- Epidemic typhus is caused by R. prowazekii, which is transmitted from lice to humans. Its primary vector is Pediculus humanus.
The bacterium is found in the louse’s feces and it may infect a person when he or she scratches the bite rubbing it into the wound. This form often caused epidemics during wars; that’s where its name comes from. Two examples of prominent outbreaks of epidemic typhus are those occurred during the Napoleonic Wars (1812) and the Irish Potato Famine (1846-1849). This form of the disease is more common in cold areas with poor hygiene and is more likely to be found in South and Central America, northern China, Africa, and some regions of the Himalayas.
- Murine (or endemic) typhus is caused by R. typhi and is transmitted from rat fleas (sometimes from cats, opossums and raccoon rats). The most common vectors are Xenopsylla cheopis and Ctenocephalides felis.
It is more common in southern states of the US and certain subtropical and temperate regions, and usually occurs in fall and summer.
- Queensland tick typhus is caused by R. australis and is transmitted from ticks.
Typhus is often confused with typhoid fever; however these are two different conditions, and typhoid means typhus-like and is caused by other bacteria. There is also scrub fever, which was previously considered a form of typhus, but now it is known to be caused by another bacterium.
Causes and risk factors
Rickettsia bacteria are usually transmitted to humans from lice, fleas, ticks, and other insects. Causes and risk factors for getting any form of typhus include:
- Living in or staying in endemic areas;
- Exposure to rat feces or insects bites;
- Exposure to poor hygiene conditions;
- Overcrowded environment.
Incubation period of the infection normally lasts from one to two weeks. The infection may be transmitted from person to person only via other lice vector.
Symptoms of typhus
The symptoms of the disease may vary depending on its form. The most common symptoms include rash and fever. The early rash is light pink in color and fades when pressing on it. Then it becomes darker and reddish. Besides, different neurological signs may develop. The symptoms of typhus usually appear as a sudden attack. Thus, symptoms of endemic typhus may include:
- High fever with chills;
- Loss of appetite;
- Red to purple rash (usually beginning on the chest and then spreading to the trunk, legs and arms);
- Acute muscles and joints pain;
- Severe headache;
- Back pain;
- Low blood pressure;
- Sensitivity to light;
- Stupor and delirium.
A mild form of endemic typhus is known as Brill-Zinsser disease, which occurs as a relapse of previous infection and causes similar symptoms.
Symptoms of murine typhus may include:
In untreated patients the symptoms usually go away within two weeks, however severe symptoms may lead to life-threatening complications, such as gangrene (death of body tissues), which leads to a loss of limbs or digits, pneumonia, renal insufficiency, and different nervous system damages.
Diagnosis and treatment
The preliminary diagnosis is made on the basis of patient’s symptoms. In order to confirm the diagnosis, a complete blood count should be performed, which may show anemia, low platelets, high level of antibodies, low levels of albumin and sodium. Differential diagnoses include such conditions as dengue fever, leptospirosis, malaria, typhoid fever, brucellosis, and some others.
Typhus is a potentially fatal disease and often leads to death if left untreated. Death also may occur in immunosuppressed and elderly people. The mortality rate for treated patients with epidemic typhus is 3-4%, and for patients with murine form of the infection is 1-4%. In most cases the infection is successfully cured with such antibiotics as azithromycin, tetracycline, doxycycline, and sometimes chloramphenicol. Antibiotic therapy should be started as soon as the diagnosis is suspected. In severe cases supportive therapy including intravenous fluids and oxygen may be required.
Most patients improve significantly within two days after treatment initiation, however, antibiotics therapy should be continued for 2-4 days after fever normalizes.
Typhus may be prevented by avoiding potential exposure to the bacterium, notably you should:
- Avoid endemic areas;
- If in endemic area, wear protective clothes;
- Use repellents to prevent insect bites;
- Avoid exposure to rats feces and fleas or lice bites;
- Avoid contacts with potential vectors of the bacterium;
- Avoid areas with poor hygiene and maintain proper hygiene.
There is also a vaccine against typhus, but it is not available nowadays. Instead you may be advised to take doxycycline if travelling to endemic areas to prevent the infection.
These articles can be used for informational purposes only. To get an accurate diagnosis consult your doctor!