Salmonella Infections in India, Spread, Hidden Burden, Resistance

Salmonella infections in India are a broader public health concern than typhoid alone. A 2026 Lancet study estimated 4.9 million typhoid cases and about 7,850 deaths in India in 2023. At the same time, non-typhoidal Salmonella (NTS), which commonly causes gastroenteritis, often goes undiagnosed because many mild cases resolve without testing.

The growing antimicrobial resistance (AMR) of Salmonella is further narrowing treatment options. India therefore needs to address the problem through food safety, safe water and sanitation, better surveillance, vaccination and antimicrobial stewardship, rather than relying mainly on antibiotics.

What Are Salmonella Infections?

Salmonella is a group of bacteria that can infect humans and animals and cause diseases ranging from foodborne diarrhoea to typhoid fever. The infections are broadly divided into typhoidal and non-typhoidal Salmonella infections.

• Typhoidal Salmonella, mainly Salmonella Typhi and Salmonella Paratyphi, causes typhoid and paratyphoid fever, collectively known as enteric fever.
• Non-typhoidal Salmonella (NTS) is mainly associated with contaminated food and commonly causes gastroenteritis, resulting in diarrhoea, abdominal cramps, fever and sometimes vomiting.
• In severe cases, Salmonella can spread beyond the intestine and enter the bloodstream, causing invasive infection and potentially life-threatening complications.
• Young children, older adults and people with weakened immunity are at greater risk of severe disease.

How Salmonella Infections Spread?

Salmonella infections are primarily transmitted through the faecal-oral route, usually when a person consumes food or water contaminated with the bacteria. The source of contamination, however, differs between typhoidal and non-typhoidal Salmonella.

• Typhoidal Salmonella is mainly transmitted from person to person through contaminated food and water. An infected person or carrier can contaminate food or drinking water when faecal matter enters the food or water supply.
• Non-typhoidal Salmonella has a wider transmission cycle involving animals, food and the environment. Poultry, eggs, meat and other animal-derived foods can carry the bacteria and transmit infection when they are contaminated or inadequately cooked.
• Contamination may occur at several stages of the food chain, beginning at farms and slaughterhouses and continuing through processing, transportation, storage, restaurants and household kitchens.
• Poor sanitation, unsafe water, inadequate food hygiene and improper storage of perishable foods can therefore increase the risk of transmission.

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The Wider Burden of Salmonella Infections Beyond Typhoid

India’s Salmonella burden extends beyond reported typhoid cases, with NTS forming an important but under-recognised part of the problem.

• Many NTS infections remain undiagnosed because mild cases often resolve without medical consultation or laboratory testing. This makes the actual burden difficult to estimate and leaves many community-level infections outside routine surveillance.
• Although most NTS infections are self-limiting, some can become invasive and cause bloodstream infections.
• The risk of serious disease is higher among young children, older adults and people with weakened immunity.

The concern, therefore, is not only the recognised burden of typhoid but also the hidden burden of NTS infections that remain outside routine diagnosis and surveillance.

Rising Antimicrobial Resistance and Treatment Challenges

Antimicrobial resistance is making serious Salmonella infections increasingly difficult to treat and reducing the effectiveness of important antibiotics.

• Fluoroquinolone resistance in S. Typhi reached about 85% during 2015–19, although it subsequently declined.
• During the 2025 enteric fever outbreak in Thane, 44 of 167 culture-confirmed cases (26.35%) were resistant to ceftriaxone.
• The Thane outbreak also found a significant association between tanker-water supply and ceftriaxone resistance, highlighting a link between water systems and resistant infections.
• Carbapenem-resistant S. Typhi carrying the blaNDM-5 gene has also been reported in India.
• Resistance across multiple antibiotic classes can result in extensively drug-resistant typhoid, leaving clinicians with limited treatment options.
• Unnecessary antibiotic use further accelerates the emergence and spread of resistant strains.

Treatment therefore requires accurate diagnosis and rational antibiotic use rather than simply shifting to stronger drugs.

• Blood culture is important for suspected typhoid and should preferably be performed before antibiotics are started.
• The Widal test should not be used alone because of its diagnostic limitations.
• Uncomplicated NTS gastroenteritis generally requires fluid and electrolyte replacement, while antibiotics are mainly reserved for severe, invasive or high-risk infections.
• Culture and antimicrobial susceptibility testing can help select an effective antibiotic when treatment is required.

Gaps in Prevention and Control

India’s main weaknesses lie in fragmented surveillance and uneven implementation of water, sanitation and food-safety measures.

• Unsafe water and inadequate sanitation continue to create conditions for typhoid transmission.
• Food contamination can occur at multiple stages, while monitoring the large informal food sector remains difficult.
• Gaps in hygiene, refrigeration and food handling increase the risk of contamination.
• Human, animal, food and environmental surveillance is not sufficiently integrated, limiting understanding of Salmonella transmission and resistance.
• Laboratory capacity gaps can restrict timely identification of infections and emerging resistance.

Way Forward

India needs to focus on preventing Salmonella transmission and reducing the need for antibiotic treatment in the first place.

• Strengthen One Health surveillance by integrating human, animal, food and environmental health data.
• Improve water, sanitation and hygiene to reduce faecal-oral transmission of typhoid.
• Strengthen farm-to-fork food safety through better hygiene, testing, refrigeration and regulatory enforcement.
• Improve food-handler training and monitoring, particularly in the informal food sector.
• Expand laboratory surveillance to detect Salmonella infections and emerging antimicrobial resistance earlier.
• Strengthen typhoid vaccination as an additional prevention measure. The WHO recommends typhoid conjugate vaccines for children from six months of age, although typhoid vaccination is not currently part of India’s universal immunisation programme.
• Strengthen antimicrobial stewardship to reduce unnecessary antibiotic use and slow resistance.
• Promote household food safety through safe water, thorough cooking of poultry and eggs, proper refrigeration and prevention of cross-contamination.

A prevention-oriented One Health approach can reduce Salmonella transmission, limit antimicrobial resistance and lessen dependence on antibiotics.