How Does Epidemic Typhus Spread & What Is The Incubation Period Of Epidemic Typhus?

Epidemic typhus is a kind of fever spread by lice found on human body called Pediculus humanus corporis. It is also found to be transmitted by fleas. In history, this disease was commonly spread after a war or after a natural disaster. This article discusses about how epidemic typhus spreads and what is the incubation period of epidemic typhus.

Epidemic typhus is also called louse borne typhus. The infection spreads through contact with infected body lice. It can spread from one person to another, especially in overcrowded places, resulting in an epidemic.¹

Epidemic typhus is caused by a coccobacillus called Rickettsia prowazekii. The two words in the name have come from two scientists one named H.T. Ricketts and the other one was Stanislaus von Prowazek. Since in human body lice spread this disease, these lice are called vectors. Rickettsia prowazekii lives in the epithelium of gut of louse. It grows and multiplies in the gut itself. After it grows completely, it explodes in the GI (gastrointestinal) tract. At this stage the louse dies. It may take 5 to 7 days for this process. This is the only organism in Rickettzia genera which kills the vector and the other organism of this particular genus does not kill their vector.

It is found that the bacteria in the dead louse is viable and is able to cause the disease even after several months. It is also present in the feces of lice and is capable of causing the disease later also. They both bite the skin of humans and enter or else it is easier for the microbe to enter if there is already a wound. Even a latent infection called BZD (Brill Zinsser disease) may also be caused by this microbe after several years or decades.

Epidemic typhus can spread by direct contact and through transmission from infected bed linens, clothing and other items of personal use. The infection rate is found to be higher in cases of poor personal hygiene, lack of access to clean clothing and overcrowding, which can spread epidemic typhus through physical contact.²

When trying to find out ways to control the spread and treat epidemic typhus, it is important to know how it presents. So, what is the incubation period of epidemic typhus? Let us understand this.

Actually, the symptoms are not expressed immediately after biting by the microbe. This period is called incubation period. The incubation period of epidemic typhus is one to two weeks, with most infections presenting themselves after ten to fourteen days.³ The early symptoms of epidemic typhus are high fever, which may last for two weeks with severe headache, dry cough and body pain. A typical red rash appears on the trunk and spreads peripherally.

Here are some of the important clinical features of epidemic typhus

Usually the symptoms are seen suddenly. The patients may have the following symptoms:

• High fever
• Hypotension
• Muscle pain
• Headache
• Rashes on the back and chest are seen first which spreads all over the body later
• Cough
• chills
• Confusion
• Sensitivity of eyes is developed to bright light
• Stupor
• Thrombocytopenia

The diagnosis of epidemic typhus can be done at different stages.

Firstly, this fever is diagnosed in the clinics like other fevers caused by Rickettsia organisms.

Blood tests confirm the disease. Some of the tests which can be conducted to confirm the disease are IFA (indirect fluorescent antibody) tests, ELISA (enzyme linked immune sorbent assay), latex agglutination, plate microagglutination, PCR (Polymerase chain reaction) and western blot.

There are different types of treatments for epidemic typhus. As a first line treatment, antibiotics can be prescribed. Often chloramphenicol or tetracycline would be effective. Doxycycline is also an effective treatment and used as appropriate. Physicians sometimes prescribe the antibiotics early itself if they suspect this disease.

The disease may lead to serious complications if not treated in time. It may lead to some neurological complications with coma, which can prove to be fatal. Some of the potential complications of epidemic typhus, if left untreated, include

• Bleeding can take place in the intestine.
• Volume of blood can be decreased.
• Inflammation of liver is also expected.

Both personal and community hygiene can help prevent the disease. Some of the tips include:

• Cleanliness is utmost important to prevent the growth of body lice.
• Direct contact with the infected person must be avoided.
• Tight and body fitting clothes can collect the microbes, hence such clothes must be avoided.
• The clothes of infected people should be washed at high temperatures of above 550 to 600 c.
• A mixture of DDT and permethrin can be dusted over the infested clothes to kill the body lice and even the eggs.
• Blood should be tested before transfusion.
• Blood collection in and around refugee camps should be stopped until epidemic typhus is completely cured.
• Travelling to the places where this disease is reported recently must be postponed.
• Repellents are also available for insects, mites, fleas and ticks. Usage of these repellents can also prevent the disease.
• Having hygienic and balanced diet is utmost important to develop immunity and to stay healthy.
• Vaccines are also available to prevent the disease.

Even though there are several medications for epidemic typhus, death can also occur if the treatment is not available in time. Sometimes misdiagnosis can also be seen as the symptoms of epidemic typhus resemble a few other diseases like typhoid. The complications and risk factors increase with increase in age of patients. The people who live in unhygienic areas are more prone to this disease. The people suffer more if they already have diseases like renal disorders, diabetes mellitus, etc. Out of the sufferers of this disease, complete and speedy recovery can be expected in children.

Now that you are aware about how does epidemic typhus spread, you can take appropriate action to prevent the infection. So keeping the surroundings clean, being hygienic, having hygienic food can bring about a lot of improvement in the areas of occurrence of this disease. Also, by being aware of the incubation period of epidemic typhus, you can pick up early signs and seek timely medical advice.

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Also Read:

• How is Epidemic Typhus or Brill-Zinsser Disease Transmitted and How Can it be Treated?