Scrub Typhus - An Overview and Management

SCRUB TYPHUS – AN OVERVIEW AND MANAGEMENT

 

Scrub Typhus is a Rickettsial disease i.e. it is caused by a bacterial group known as Rickettsia which gets transmitted via arthropods (the carrier/vector for the organism). The vectors for Rickettsia are Ticks, Louse, Mites, or Fleas. There are two main groups of rickettsial fever; spotted fever and typhus fever. Here we will talk about Typhus fever.

This is usually a disease of the Tropics and is also endemic to Nepal and was also noted to increase in Nepal following the earthquake of 2015. It was first noted in Nepal in 1981; a study done by Brown-et-al(1). A recent study on Scrub Typhus Seroprevalence by Pokhrel-et-al (2) showed that among 2070 febrile patients, Scrub typhus accounted for 12.2% (n = 253) of total febrile illnesses and among 253 scrub typhus patients, 53.4% were female.

Typhus fever a.k.a Scrub Typhus is caused by Orientia tsutsugamushi (previously called Rickettsia tsutsugamushi). The Vector(carrier) is Mites (कण/ सुलसुले in Nepali) and is transmitted via the bite of the infected larval form of the mite (known as chigger mites) i.e. the bacteria infect the carriers (mites) and the baby mites when they bite us introduce the bacteria to our body.

The clinical picture of the disease usually is sudden or abrupt. Mild or subclinical(a disease that is not severe enough to present definite or readily observable symptoms) cases are common.

  • SYMPTOMS (what the patient complains)

    1. Headache (often retro-orbital)

    2. Fever (Remittent fever; i.e. temperature difference between maximum and minimum is more than 1 C)

    3. Cough

    4. Diarrhea

    5. Malaise

    6. Weakness

  • In severe illness, the above symptoms increase with APATHY (lack of interest) and PROSTRATION (extreme physical weakness).

  • SIGNS (what the Doctor sees)

    1. RASH: Red, Flat to raised (maculopapular) rash often appears on about 5-7th day and spreads to the trunk, face, and limbs including the palms and soles. The rash fades by about the 14th day.

    2. ESCHAR: Round black area of skin surrounded by swelling and redness, denotes the SITE OF THE BITE. (in the photo below); might not be detected during the presentation.

    3. LYMPHADENOPATHY: Generalized, Painless enlargement of Lymph Glands.

    4. IN SEVERE INFECTION: the patient is extremely weak with Cough, may develop Pneumonia, Confusion, and Deafness. In the late stages, Cardiac and Renal Failure and Hemorrhage may also develop.

Eschar (https://en.wikipedia.org/wiki/Eschar)

In Nepal, the increasing cases of Scrub Typhus have to be looked at in Rural and Urban settings. In rural areas where the maximum of the patients are farmers, they come in direct contact with the vectors in the field during monsoon season. In urban settings, improper waste disposal attracts rats which harbor the mites and lead to the disease. (3)

INVESTIGATION (How to confirm diagnosis/ What test to do?):

When suspecting a case of Scrub typhus your physician will not only send in a specific test but rather order a series of panel tests because many diseases will fall in the profile and needs to be ruled out. History of the disease and physical examination is the backbone, so you must properly tell your doctor each and every detail, even a small detail as jumping into a rice/paddy field for recreation purposes in an endemic area is important information! A list of possible diseases you could have based on your symptoms is called a differential diagnosis. Your Doctor will then send investigations to find out what you have from the list of differentials. In the case of Scrub Typhus, other probable illnesses which present with similar symptoms include Malaria, Typhoid, Leptospirosis, and Meningococcal Sepsis. You will be sent for blood investigations.

  • The simple and cheap test done for Scrub Typhus is called the Weil-Felix test (which is a basic antigen-antibody agglutination test), however is now replaced by more sensitive and specific serological tests (e.g ELISA, PCR, IFA, LAMP, etc).

  • To rule out Malaria: Peripheral blood smear is done.

  • To rule out Typhoid: Widal test, Urine routine, and Blood culture is sent.

  • Other tests which may be done include:

    • Sputum culture

    • To rule out Meningococcal infection (if suspected): Lumbar Puncture is done.

    • CT scan of the chest and abdomen

    • Echocardiography.

TREATMENT:

Scrub Typhus is readily treatable and curable. It responds very well to an Antibiotic called Doxycycline (DO NOT TAKE WITHOUT DOCTORS PRESCRIPTION; as there is a certain way you need to take this medication). Resistant strains may be present and might need treatment with Rifampicin.

PREVENTION:

  • Proper Garbage Disposal.

  • Extermination of Rat habitat near households.

  • Proper coverage of body while working in fields followed by proper body wash and hygiene.

  • To prevent from developing into severe illness timely visit to the Doctor following fever and notable rash.

 

WHO TO VISIT?

Scrub typhus and its treatment fall under the domain of Infectious Disease. You need to visit a specialist who has completed their MD in Internal Medicine preferably with a specialization in Infectious Disease itself. However, if you are in Rural areas, you will HAVE TO VISIT the District Hospital and get treated with the MDGP who is in charge of the hospital setting. If you have developed resistant disease or if the disease is severe, you will be referred to a Tertiary Center that looks after infectious diseases most likely to Sukraraj Tropical and Infectious Disease Hospital, Teku, Kathmandu. You may visit the hospital directly first as well.

REFERENCES:

  1. Brown G.W, Shirai A, Gan E,  Bernthal P. Antibodies to typhus in Eastern Nepal, Transactions of The Royal Society of Tropical Medicine and Hygiene, Volume 75, Issue 4, 1981, Pages 586–587(https://doi.org/10.1016/0035-9203(81)90210-8).

  2. Pokhrel A, Rayamajhee B, Khadka S, Thapa S, Kapali S, Pun S.B, Banjara M.R, Joshi P, Lekhak B, and Rijal K.R. Seroprevalence and Clinical Features of Scrub Typhus among Febrile Patients Attending a Referral Hospital in Kathmandu, Nepal. Trop. Med. Infect. Dis. 2021, 6(2), 78 (https://doi.org/10.3390/tropicalmed6020078)

  3. Acharya K.P, Adhikari N, Tariq M. Scrub typhus: A serious public health issue in Nepal. Clinical Epidemiology and Global Health Volume 8, Issue 3, September 2020, Pages 815- 817 (https://doi.org/10.1016/j.cegh.2020.02.006)

 

Dr. Suyash Timalsina

Medical Officer

Danphe Care