FAQs on Scrub Typhus

1. What is scrub typhus?
Answer: Scrub typhus is a zoonotic disease caused by the gram-negative bacteria Orientia tsutsugamushi. There are at least six strains of the Orientia tsutsugamushi bacterium (Karp, Kato, Kuroki, Kawasaki, Shimokoshi, and Gilliam). Scrub typhus does not spread from one human to another. Instead, the disease is transmitted when a chigger (larva of mite belonging to the species Leptotrombidium delicense) carrying the bacteria bites any human. The bite from the bite causes a distinctive black eschar. The presence of Eschar during physical examination increases the high probability of getting diagnosed with scrub typhus. Scrub typhus is also called bush typhus because the chiggers are mainly found in the bushes, and humans walking through those bushes get infected with the scrub typhus disease. Scrub typhus is also called Tsutsugamushi disease.

2. Which countries have a high incidence of Scrub Typhus?
Answer: Far East of Russia, Japan, Northern Australia, and Afghanistan are the endemic regions to Scrub Typhus and are thus known as the Tsutsugamushi triangle.
Scrub typhus is a significant public health problem in the Asia-Pacific region, majorly including countries like:

• Korea
• Japan
• China
• Taiwan
• India (Southern part of India, followed by North India, reports high cases of scrub typhus)
• Indonesia
• Thailand
• Srilanka
• Philippines

3. What are some of the risk factors for scrub typhus?
Answer: The risk factors for scrub typhus include:

• Presence of scrub vegetation around the house
• Presence of wood piles around the house
• Presence of cattle around the house
• The habit of not changing undergarments and overclothes before sleeping
• People resting on the grass surrounded by scrub vegetation after getting tired from farming and gardening activities.
• Presence of rodents in the house
• Lack of proper toilets inside the house
• People working on farms during the rainy season
• People of older age
• Traveling to areas where scrub typhus is common

4. What are the symptoms of scrub typhus disease?
Answer: The symptoms of scrub typhus appear after 5-14 days of being bitten by a chigger. The signs and symptoms of scrub typhus include:

• A black, scab-like region at the site of the chigger bite, known as Eschar
• Myalgia (Muscle Pain)
• Body pain
• Fever and chills
• Rash
• Enlarged Lymph Nodes
• Vomiting and abdominal pain
• Some patients may experience mental changes, ranging from confusion to coma

In severe cases, scrub typhus can show symptoms such as:

• Hypotension (low blood pressure)
• Thrombocytopenia (deficiency of platelets in the blood)
• Leucocytosis (increase in white blood cells)
• Hypoxia (difficulty breathing)
• Acute renal failure
• Hypoalbuminemia (deficit of albumin)
• Hepatic dysfunction (liver not working properly)

5. How is scrub typhus diagnosed?
Answer: Do not treat scrub typhus on your own. Always visit a registered physician for proper diagnosis and treatment of scrub typhus. After confirming scrub typhus through appropriate diagnostics, the physician proceeds towards the treatment of the disease.

Diagnosis of scrub typhus can be divided into two methods:

1. Direct Method
   The direct method involves the isolation and culture of the bacteria in different cell lines like:
   • The fibroblast cell line of the Mouse
   • Cancer cell line
   • Baby Hamster Kidney cell lines
     DNA-based diagnosis using different genetic markers by PCR also comes under the direct method of diagnosis.
2. Indirect Method
   The indirect methods involve laboratory-based serological assays used to detect the presence of immunoglobulin G (IgG) and immunoglobulin M (IgM) in the patient’s blood. Indirect immuno-based methods for diagnosis involve:
   • Weil-Felix test
   • Immunofluorescence assay (IFA)
   • Immunochromatographic test (ICT)
   • Indirect Enzyme-Linked Immunosorbent Assay (ELISA) (Most Reliable Method)
   • Immunoperoxidase assays.

6. What are the health complications associated with scrub typhus?
Answer: The health complications associated with scrub typhus includes:

• Chest Abnormalities include:
  
  • Intestinal Pneumonia
  • Cardiomegaly
  • Pulmonary Edema
  • Pleural Effusion
  • Hilar Lymphadenopathy
  • Focal atelectasis
• Neurological Complications include:
  
  • Seizure
  • Cranial nerve deficits (impairment of cranial nerves)
  • Vasculitic cerebral infarct (the inflamed vessel that blocks the flow of oxygen to the brain causing loss of brain function)
  • Brain hemorrhages (ruptured blood vessels inside the brain)
  • Polyneuropathy
  • Sensorineural hearing loss (damage to the nerve connecting the ear to the brain)
• Myocarditis
• Acute Kidney Injury/Acute Renal Failure
• Multiorgan Dysfunction

7. Can pregnant women get scrub typhus disease?
Answer: Yes, pregnant women can also get scrub typhus. The outcome of scrub typhus in pregnant women is not good. Study reports have shown the following complications associated with scrub typhus in pregnant women:

• Preterm childbirth
• Stillbirth
• Spontaneous abortion
• Intrauterine deaths
• Vertical transmission of scrub typhus to neonates
  However, providing the proper treatment for scrub typhus at the right time can prevent fatal outcomes for mother and child.

8. How is scrub typhus treated?
Answer: Do not treat scrub typhus on your own. Always visit a registered physician for proper diagnosis and treatment of scrub typhus. After confirming scrub typhus through proper diagnostic, the physician proceeds towards the treatment of the disease.
The treatment for scrub typhus is divided into two stages:

1. 1. The primary Stage of Treatment (Used for non-complicated cases) involves:
      
      • Treatment of scrub typhus in adults
        Doxycycline 200 mg every day, divided into two doses for seven days for individuals weighing more than 45 kg.
        Or
        Azithromycin strength 500 mg once a day for five consecutive days.
      • Treatment of scrub typhus in children
        Doxycycline in the dose of 4.5 mg/kg body weight/day in two divided doses for children below 45 kg
        Or
        Azithromycin in a single dose of 10mg/kg body weight for five days.
      • Treatment of scrub typhus in Pregnant women
        Azithromycin 500 mg/ day for five days should be administered. Azithromycin is the drug of choice for scrub typhus in pregnant women.
   2. The Secondary stage of treatment (Used for complicated cases).
      The treatment involves:
      • Intravenous doxycycline 100mg twice daily in 100 ml normal saline to be administered as an infusion over half an hour initially followed by an oral dose for 7-15 days of complete therapy.
        OR
      • Intravenous Azithromycin [500mg IV in 250 ml normal saline over 1 hour once daily for 1-2 days followed by oral therapy to complete five days of treatment].
        OR
      • Intravenous chloramphenicol [50-100 mg/kg/d six hourly doses to be administered as an infusion over one hour initially followed by oral therapy to complete 7-15 days of treatment].

References

1. George, T., Rajan, S. J., Peter, J. V., Hansdak, S. G., Prakash, J., Iyyadurai, R., Mathuram, A., Antonisamy, B., Ramanathan, K., & Sudarsanam, T. D. (2018). Risk Factors for Acquiring Scrub Typhus among the Adults. Journal of global infectious diseases, 10(3), 147–151. https://doi.org/10.4103/jgid.jgid_63_17
2. Devamani, C. S., Schmidt, W., Ariyoshi, K., Anitha, A., Kalaimani, S., & Prakash, J. A. J. (2020). Risk Factors for Scrub Typhus, Murine Typhus, and Spotted Fever Seropositivity in Urban Areas, Rural Plains, and Peri-Forest Hill Villages in South India: A Cross-Sectional Study, The American Journal of Tropical Medicine and Hygiene, 103(1), 238-248. Retrieved Mar 31, 2022, from https://www.ajtmh.org/view/journals/tpmd/103/1/article-p238.xml
3. Scrub Typhus, Centers for Disease control and Prevention.
   Accessed at
   https://www.cdc.gov/typhus/scrub/index.html#:~:text=Scrub%20typhus%2C%20also%20known%20as,body%20aches%2C%20and%20sometimes%20rash.
4. Xu, G., Walker, D. H., Jupiter, D., Melby, P. C., & Arcari, C. M. (2017). A review of the global epidemiology of scrub typhus. PLoS neglected tropical diseases, 11(11), e0006062. https://doi.org/10.1371/journal.pntd.0006062
5. Rajan, S. J., Sathyendra, S., & Mathuram, A. J. (2016). Scrub typhus in pregnancy: Maternal and fetal outcomes. Obstetric medicine, 9(4), 164–166. https://doi.org/10.1177/1753495X16638952
6. Kim DM, Kim HL, Park CY, Yang TY, Lee JH, Yang JT, Shim SK, Lee SH. Clinical usefulness of eschar polymerase chain reaction for the diagnosis of scrub typhus: a prospective study. Clin Infect Dis. 2006 Nov 15;43(10):1296-300. doi: 10.1086/508464. Epub 2006 Oct 12. PMID: 17051495.
7. Kundavaram AP, Jonathan AJ, Nathaniel SD, Varghese GM. Eschar in scrub typhus: a valuable clue to the diagnosis. J Postgrad Med. 2013 Jul-Sep;59(3):177-8. doi: 10.4103/0022-3859.118033. PMID: 24029193.
8. Rahi M, Gupte MD, Bhargava A, Varghese GM, Arora R. DHR-ICMR Guidelines for diagnosis & management of Rickettsial diseases in India. Indian J Med Res. 2015 Apr;141(4):417-22. doi: 10.4103/0971-5916.159279. PMID: 26112842; PMCID: PMC4510721.
9. Rose W, Rajan RJ, Punnen A, Ghosh U. Distribution of Eschar in Pediatric Scrub Typhus. J Trop Pediatr. 2016 Oct;62(5):415-20. doi: 10.1093/tropej/fmw027. Epub 2016 Apr 27. PMID: 27122479.
10. Chakraborty, S., & Sarma, N. (2017). Scrub Typhus: An Emerging Threat. Indian journal of dermatology, 62(5), 478–485. https://doi.org/10.4103/ijd.IJD_388_17
11. Chin, J. Y., Kang, K. W., Moon, K. M., Kim, J., & Choi, Y. J. (2018). Predictors of acute myocarditis in complicated scrub typhus: an endemic province in the Republic of Korea. The Korean journal of internal medicine, 33(2), 323–330. https://doi.org/10.3904/kjim.2016.303
12. Jayaprakash V, Vamsikrishna M, Indhumathi E, Jayakumar M. Scrub typhus-associated acute kidney injury: A study from a South Indian Tertiary Care Hospital. Saudi J Kidney Dis Transpl [serial online] 2019 [cited 2022 Mar 3];30:883-90. Available from: https://www.sjkdt.org/text.asp?2019/30/4/883/265464
13. Jamil, M. D., Hussain, M., Lyngdoh, M., Sharma, S., Barman, B., & Bhattacharya, P. K. (2015). Scrub typhus meningoencephalitis, a diagnostic challenge for clinicians: A hospital based study from North-East India. Journal of neurosciences in rural practice, 6(4), 488–493. https://doi.org/10.4103/0976-3147.169769
14. Song, S. W., Kim, K. T., Ku, Y. M., Park, S. H., Kim, Y. S., Lee, D. G., Yoon, S. A., & Kim, Y. O. (2004). Clinical role of interstitial pneumonia in patients with scrub typhus: a possible marker of disease severity. Journal of Korean medical science, 19(5), 668–673. https://doi.org/10.3346/jkms.2004.19.5.668
15. Attur RP, Kuppasamy S, Bairy M, Nagaraju SP, Pammidi NR, Kamath V, Kamath A, Rao L, Bairy I. Acute kidney injury in scrub typhus. Clin Exp Nephrol. 2013 Oct;17(5):725-729. doi: 10.1007/s10157-012-0753-9. Epub 2013 Jan 5. PMID: 23292176.
16. Gaba, S., Sharma, S., Gaba, N., & Gupta, M. (2020). Scrub Typhus Leading to Acute Liver Failure in a Pregnant Patient. Cureus, 12(9), e10191. https://doi.org/10.7759/cureus.10191
17. Ahmed, A. S., Kundavaram, A. P., Sathyendra, S., & Abraham, O. C. (2014). Acute pancreatitis due to scrub typhus. Journal of global infectious diseases, 6(1), 31–34. https://doi.org/10.4103/0974-777X.127949
18. Bonell A, Lubell Y, Newton PN, Crump JA, Paris DH. Estimating the burden of scrub typhus: A systematic review. PLoS Negl Trop Dis. 2017 Sep 25;11(9):e0005838. doi: 10.1371/journal.pntd.0005838. PMID: 28945755; PMCID: PMC5634655.