What is Typhus Fever?
Typhus fevers are caused by microscopic organism called ‘rickettsia’ which are transmitted to man by external parasites (lice, fleas etc). A person infected with ‘rickettsia’ develops severe fever, headaches, skin rashes may develop bronchitis or pneumonia-like symptoms. There are in reality, three principle types of Typhus fevers, differing markedly in their causative agents, transmitting agents, and distribution and severity of symptoms.
Types of Typhus Fever and Caused by:
1. Classical Typhus:
Classical Typhus also called epidemic, European or louse typhus, occurs chiefly in Europe, Asia and Northern Africa. Not truly a tropical disease, it appears suddenly in epidemic form in population weakened by famine, or disease or in groups of people crowded closely together in armies, jails, concentration camps etc. It is carried from person to person by body lice and frequently reaches epidemic proportion near the end of winter, since heavy clothing and crowding favor lice infections.
The lice become infected by ingesting the blood of a diseased person. The rickettsia multiply within the louse and pass out of the body in the excreta after the second day, infection is produced by rubbing the infected areas, wounds or other breaks in the skin.
The onset is abrupt, with fever, headaches, general body aches, followed by appearance on the eighth or ninth day, of a skin rash on abdomen, chest, arms and legs. Bronchitis and bronchopneumonia are frequent complications. The death rate in epidemics is in great, in Egypt, for example, there are 40,000 cases in 1943 with over 8000 deaths. In the Serbian epidemic, following World War I, the mortality rate varied from 30 and 70 percent.
2. Murine Typhus:
Murine Typhus, also known as New World, endemic or flea typhus, caused ‘rickettsia mooseri’ is a disease of rats normally transmitted from rat to rat by several species of rats fleas (or rat lice in certain parts of the world). It is found in certain parts of Europe, Asia, Africa, Mexico and along the Atlantic and Gulf coasts of United States.
Human beings become infected when living in close proximity to infected rats, since rat fleas will bite man quite readily. Although the general symptoms of Murine Typhus are similar to those of the classical form, the clinician course is generally milder and the death rate is low.
3. Scrub Typhus:
Scrub Typhus, also called tsutsugamushi, Japanese river fever or mite typhus is widespread throughout the Asiatic-Pacific region and has been carried to other areas by migrants.
Probably a disease of field mice, it is caused by R. orientalis (a winged fly species) and is transmitted by several species of mites (Trombicula). The bite of the larval form of the mite, usually on the neck or in the groin, often followed by the development of the small local ulcer, and the lymph nodes in the area become enlarged and tender. The fever in Scrub Typhus is similar to that of the other typhus fever but death rate of the Scrub Typhus is generally greater than that of the Murine Typhus.
How to Control Typhus Fever:
Control of the transmitting agents is very important in controlling the incidence of these diseases. The body louse lives mainly attached to the clothing worn next to the body. From this attachment it takes two bloods a day, and lays eggs along the seams of the clothing. The ‘crab louse’ lives attached to the public hair and ‘head louse’ lives among the hair of the head. Destruction of the adult lice can be accomplished by the use of the insecticide powders and steam sterilization is effective on the eggs. Frequent bathing and changing of the underclothes is also important.
The best control of the rat fleas is by through eradication of the rats. Control of the mite vector of the Scrub Typhus is extremely difficult and a serious problem in the Pacific area during the World War II. Infected mice and their parasitic mites are thickest in the patches of the tall grass, removing the clumps of the grass from camps areas by bulldozers affordable considerable protection. Individual protection may be obtained through the use of repellent such as ‘dimethylpthalate’ for clothing or an insecticide such as benzyl benzoate for buildings, tents etc.
Within the past few years remarkable cures have been effected through the use of the antibiotics aureomycin, chloramphenicol and terramycin. These agents apparently do not destroy the living rickettsia but suppress their growth. Thus permit the individual to develop immunity.
Prevention of Typhus Fever by means of artificially acquired immunity is also possible. Vaccines are now being prepared for use against the organisms of Typhus Fever.
Is Typhus Contagious?
Typhus which is known as as epidemic and endemic forms, is caused by by microscopic organism called ‘rickettsia’ which are transmitted to man by external parasites (lice, fleas etc). A person infected with ‘rickettsia’ develops severe fever, headaches, skin rashes may develop bronchitis or pneumonia-like symptoms. It primarily spreads through the bites of infected fleas, lice or mites that have fed on animals carrying the bacteria.
Direct person to person transmission of typhus is rare. In most cases, the infection is spread through vectors like fleas and lice. However, in close and prolonged contact with an infected ‘individual, transmission can occur through the lice feces or crushed lice or flea fluid.
Though typhus is not considered as highly contagious between man to man, but individual’s exposure to the infected areas or in groups of people crowded closely together in armies, jails, concentration camps etc. can increase the risk of contracting the disease.