Typhoid fever, a life-threatening systemic infection, and its increasing resistance to widely used antibiotics, is the focus of a recent study published in The Lancet Microbe journal. According to available data, this fever leads to 11 million infections and over 100,000 deaths each year, with South Asia accounting for 70% of the global disease burden.
About Typhoid
Typhoid fever is caused by the bacterium Salmonella enterica serovar Typhi, more commonly known as Salmonella Typhi. This strain is exclusively carried by humans, with no other animal carriers discovered to date. The infection is transmitted through fecal-oral route, often by the ingestion of contaminated food or water.
One in twenty people who recover from typhoid without treatment becomes a ‘carrier’ who, despite having no symptomatic illness, carries the bacteria in their feces and urine. This person poses a risk of infecting others for about three months, or sometimes up to a year. Regions like Asia (specifically India, Pakistan, and Bangladesh), Africa, the Caribbean, Central and South America, and the Middle East are among the high-risk areas for travelers.
Symptoms of Typhoid
Symptoms of typhoid fever range from mild to severe and can last for about a month if untreated. These include fever, fatigue, malaise (a general feeling of unwellness), sore throat, persistent cough, and headaches.
Prevention and Treatment of Typhoid
The typhoid vaccine, which is available as an oral medication or a one-off injection, is an effective prevention method. However, it is only 50–80% effective. The detection of typhoid fever requires prompt treatment with antibiotics.
Drug Resistance in Typhoid
The effectiveness of antibiotics is threatened by emerging drug-resistant strains. The existence of these resistant strains means that certain antibiotics or drugs designed to kill them no longer work, allowing the bacteria to spread rapidly and posing a serious public health risk.
Since the year 2000, multi-drug-resistant (MDR) typhoid has steadily declined in Bangladesh and India, remained low in Nepal, but slightly increased in Pakistan. However, these regions are now confronted with other antibiotic-resistant strains. Multi-dric resistance (MDR) refers to lack of susceptibility to at least one agent in three or more chemical classes of antibiotic.
Strains were labeled as MDR if they had genes providing resistance to antibiotics such as ampicillin, chloramphenicol, and trimethoprim/sulfamethoxazole. A new type of resistance observed in strains coined XDR typhoid includes resistance to antibiotics like azithromycin in India, Bangladesh, Nepal, and Pakistan. Extensive Drug Resistance (XDR) typhoid is triggered by a strain that is resistant to at least five antibiotic classes recommended for treating typhoid fever.
Way Forward
A comprehensive policy framework and an integrative approach are necessary to prevent, control, and eliminate typhoid fever. India’s Ministry of Health, for instance, is considering incorporating new typhoid conjugate vaccines into the national immunization program. Two WHO-prequalified vaccines have been developed in India by Bharat Biotech and Biological E.
Last Modified: February 15, 2024