Scrub Typhus

Scrub Typhus total guide

What is scrub typhus?

It is a rickettsiosis whose initial manifestations are variable but which are often characterized by brutal headaches, chills, prostration, high fever, cough and severe muscle pain. A macular rash on the skin appears between the fifth and sixth day; initially limited to the upper part of the trunk, it then extends to the whole body, to the face, to the palms and to the soles of the feet. The case fatality rate is between 1% and 20%.

scrub typhus Cause:

The etiological agent, Rickettsia prowazekii, is transmitted by the body’s lung, Pediculus humanus corporis, which becomes infected by taking a meal on an acute febrile patient. (Head lice or pubic lice play no role in transmission.) By feeding on the second host, infected lice excrete rickettsia. The man is infected by rubbing the projections of crushed fragments or fragments of insects at the point of return or scratching lesions.
Prevalence: The body louse lives in clothing and multiplies very quickly when the conditions of hygiene leave something to be desired. It proliferates very quickly in refugee camps or other situations characterized by overcrowding and poor sanitation and we can expect increased risk during the rainy season when there is a tendency to cover yourself further.

Since the Second World War, major outbreaks of typhus have occurred, mostly in Africa, with most cases reported in three countries: Burundi, Ethiopia and Rwanda. In Ethiopia, the number of cases reported each year ranged from 7,000 to 17,000 (except in 1979, where a higher number were reported), although most were not confirmed in the laboratory. In the 1970s, major epidemics occurred in Burundi and Rwanda, evidenced by serological examination and isolation of the etiological agent: in 1975 alone, 9000 cases were reported in Burundi. In 1996, Burundi notified 3,500 cases and the number jumped to 20,000 between January and March 1997.

scrub typhus Warning signs:

There is a risk of typhus when people in overcrowded and infested lice are suddenly seized with high fever, chills, headache, generalized pain and fatigue. extremes that alternate with bouts of agitation, with symptoms being followed after five to six days of macular rash. The clinical diagnosis can be confirmed serologically.

scrub typhus Latency and recurrence:

Man is the only reservoir of rickettsia and it is he who maintains the infection between epidemics. Outbreaks occur in cold regions when people are crammed into lice infested places where hygiene is inadequate. Exanthematous typhus may give rise to mild symptoms several years after first access (Brill-Zinsser disease).
Period of transmission: The disease is not directly transmitted from one person to another. The patients are infectious for the lice during the febrile period and perhaps also two to three days after the defervescence. In an infected louse, rickettsia pass into the droppings two to six days after the blood meal; if the louse is crushed, it will be infectious more quickly. The lung invariably dies within two weeks of infection; but rickettsia can remain viable in his corpse for weeks.

Sensitivity and Resistance:

The sensitivity is general. After an access, the patient generally retains a long-term immunity.

scrub typhus Treatment:

A single dose of 200 mg doxycycline (two tablets), regardless of the patient’s age.

scrub typhus Control measures:
Cleanliness plays an important role in the prevention of pediculosis. The simplest method to combat occasional infestations is to wear the infested clothing at a temperature of at least 70 ° C for at least one hour. In emergency situations, it can be difficult or impossible to wash properly and there is a shortage of fuel to heat the water. In general, chemical control is required, especially when typhus threatens. There are two methods of applying the products: dusting (either individual or in mass treatment) and the treatment of clothing. In view of the development of resistance to insecticides among lice, it is important to determine their susceptibility to insecticides before selecting one or another insecticide for a campaign.

For the control of lice, insecticidal powders may be used, for example permethrin (0.5%), temephos (2%), propoxur (1%) or carbaryl (5%). Careful insecticide treatment of infested clothing should be sufficient, but it may be necessary to repeat the operation every three or four weeks if the infestation persists or if re-infestation is suspected. It is not recommended to treat people with dermatological problems or visible wounds. The precautions for use on the label of the insecticide should be strictly adhered to. In case of widespread infestation, it is recommended to systematically treat all members of the community.

Insecticide treatment is simple and inexpensive and protects for at least six weeks, even after several washings. This avoids the problem of repeated treatments in areas where it is difficult to access regularly. Permethrin, a pyrethroid, is recommended for impregnation. It is diluted in water to obtain an optimum dose of 0.65-1 g / m2 of clothing.

People with pediculosis who are at risk for typhus should be observed for 15 days after application of a residual insecticide.

All their immediate contacts must be under surveillance for two weeks.

In case of death from typhus before deworming, the clothes of the deceased must be de-wormed by the careful application of an insecticide.

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