Scrub Typhus-Prelims-2017

There is rise in number of cases of Scrub Typhus in Himachal Pradesh. Scrub typhus – a mite-borne disease, has claimed 20 lives and affected over 700 people across the State.
About Scrub Typhus:

  • Scrub typhus is an acute, febrile, infectious illness that is caused by Orientia (formerly Rickettsia) tsutsugamushi.
  • It is also known as tsutsugamushi disease.
  • Scrub typhus was first described from Japan in 1899. Humans are accidental hosts in this zoonotic disease.
  • The term scrub is used because of the type of vegetation (terrain between woods and clearings) that harbours the vector; however, the name is not entirely correct because certain endemic areas can also be sandy, semi-arid and mountain deserts.
  • It is an obligate intracellular gram-negative bacterium that has a large number of serotypes. This pathogen does not have a vacuolar membrane; thus, it grows freely in the cytoplasm of infected cells. Because they are intracellular parasites, they can live only within the cells of other animals.
  • Scrub typhus is transmitted to humans and rodents by some species of trombiculid mites. The mite is very small (0.2 – 0.4mm) and can only be seen through a microscope or magnifying glass.
  • Humans acquire the disease from the bite of an infected chigger). The bite of the mite leaves a characteristic black eschar that is useful to the doctor for making the diagnosis. The adult mites have a four-stage lifecycle: egg, larva, nymph and adult. The larva is the only stage (chigger) that can transmit the disease to humans and other vertebrates, since the other life stages (nymph and adult) do not feed on vertebrate animals. Both the nymph and the adult are free-living in the soil.


  • Headache, fever, chills, rash, cough, red lesion at the site of the bite


  • Skin biopsy – sample of the skin from your rash will be tested in a lab
  • Western blot – test to identify presence of typhus bacteria
  • Immunofluorescence test – using fluorescent dyes to detect typhus in samples of mucus
  • Blood test – blood sample tested for the presence of infection


  • Administration of antibiotics like doxycycline, cholramphenicol, ciprofloxacin

Source: The hindu, Wikipedia

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