drug-resistant-typhoid

Why in News?

Typhoid fever-causing bacteria are becoming more and more resistant to some of the most widely used antibiotics, according to The Lancet Microbe journal.

Typhoid fever causes almost around 11 million infections and more than 1,00,000 deaths per year, with South Asia accounting for 70% of the global disease burden.

What is Typhoid?

About:

Typhoid fever is a life-threatening  infection caused by the bacterium Salmonella Typhi. Till date humans are the only carriers, no other animal carrier has been found.

Transmission:

  • Typhoid fever is transmitted through the faecal-oral route, mostly through intake of contaminated food or water.
  • If kept untreated, about one person in 20 who recovers from typhoid turns a ‘carrier’. Despite having any symptoms, they carry the bacteria through their faeces and urine, and can infect others for a period of about three months to one year.
  • Travellers are at high risk of developing typhoid fever in many endemic countries, especially in parts of Asia (especially India, Pakistan, and Bangladesh), Africa, the Caribbean, Central and South America, and the Middle East.

Symptoms:

Symptoms range from mild to severe, and can last for about one month without treatment. Most common traits are fever, fatigue or tiredness, feeling of unwellness, sore throat, persistent cough, headache.

Prevention:

Vaccine is available as an oral medication or a one-off injection. Vaccines are of two types - live attenuated or inactivated.

The typhoid vaccine is only 50–80% effective.

Treatment:

Typhoid fever requires prompt treatment with antibiotics.

Drug Resistance:

  • The effectiveness of antibiotics is endangered by the emergence of drug resistant strains.
  • This means antibiotics or drugs designed to kill them no longer work, allowing them to spread rapidly and thus posing a greater risk to public health.
  • Since 2000, multi-drug-resistant (MDR) typhoid has declined steadily in Bangladesh and India, with few infections still found in Nepal and Pakistan
  • However, these are getting replaced by drug resistant strains, according to the study conducted by researchers from Stanford University, Christian Medical College Vellore and others.
  • Multi-drug resistance (MDR) is defined as lack of susceptibility to at least one agent in three or more chemical classes of antibiotic like ampicillin, chloramphenicol, and trimethoprim/ sulfamethoxazole.
  • A new type of drug resistance is observed in strains termed XDR typhoid. Extensive Drug Resistance (XDR) typhoid is caused by a strain that is resistant to at least five antibiotic classes recommended for treating typhoid fever.
  • Strains resistant to the antibiotic (azithromycin) have been seen in India, Bangladesh, Nepal and Pakistan.

Way Forward

  • An integrated and comprehensive policy framework is required for the prevention, control and elimination of typhoid fever.
  • India’s Health Ministry is considering to introduce new typhoid conjugate vaccines into the national immunization program. 
  • Two WHO prequalified vaccines have been developed in India by Bharat Biotech and Biological E.