Typhoid, cholera, jaundice: how contaminated water actually makes you sick

Ask someone in India what waterborne illness looks like and you'll get four words back — typhoid, cholera, jaundice, and "loose motions" — used loosely, sometimes interchangeably, rarely with a clear sense of what separates a stomach bug you sleep off from one that needs a hospital. They're different diseases, caused by different organisms, with different timelines and different risks. What they share is the route in: a pathogen from someone else's waste, reaching your gut through water or food that wasn't treated properly.

That shared route is why they cluster together on a site about water, and why they spike together every monsoon — even though the diseases themselves behave nothing alike, and the fix, in every case, is the same one: treat the water.

Typhoid: a fever that builds instead of breaking

Typhoid is caused by Salmonella Typhi, a bacterium that infects only humans — it has no animal reservoir, so every case traces back to someone else's faecal contamination reaching water or food, often via a person who is infected but not yet visibly sick. You swallow the bacteria, it crosses the gut wall, and spreads through the bloodstream rather than staying local, which is why the illness looks systemic rather than like ordinary food poisoning.

The signature is a fever that climbs rather than spikes and breaks — often reaching 39–40°C, sustained over days, with weakness, abdominal pain, headache, and appetite loss. Adults commonly get constipated rather than diarrhoeal; children are more likely to have loose stools alongside the fever. Left untreated, symptoms can persist for weeks and, in a minority of cases, progress to intestinal bleeding or perforation — a genuine emergency.

India carries a large share of the world's typhoid burden — published estimates vary widely by methodology, running from roughly a quarter to about half of global cases — with the heaviest toll falling on school-age children, roughly 5 to 15 years old, rather than infants. A separate, harder problem is drug resistance: a growing fraction of cases no longer respond to fluoroquinolone antibiotics, the older first-line treatment, which is one reason a fever that doesn't improve within a few days of starting treatment needs a doctor's follow-up rather than a change of home remedy.

Prevention is mostly about the water and food chain — safe drinking water, food from sources with reasonable hygiene, and hand-washing, since the bacteria travel on hands as readily as in water. A typhoid conjugate vaccine exists and is available privately in India, whose manufacturers also supply it globally, though it isn't yet part of the government's universal immunisation schedule.

Cholera: the one where speed matters more than diagnosis

Cholera comes from Vibrio cholerae, spread almost entirely through water and food contaminated with faecal matter, with symptoms appearing anywhere from 12 hours to five days after exposure. Only around 1 in 10 infected people develop the classic illness — but for those who do, the danger isn't the bacterium itself, it's how fast the body loses fluid.

Severe cholera produces profuse, watery diarrhoea — described as "rice-water" stool — often with vomiting, and the fluid loss can run to litres within hours. Left uncorrected, that becomes severe dehydration and shock, and can kill within hours of onset. This is the one illness on this list where the clock, not the lab test, decides the outcome.

Oral rehydration solution (ORS) — the WHO-formulated mix of salts and glucose in water — is the correct first response, started at home the moment watery diarrhoea looks unusually severe, without waiting for a diagnosis. It replaces fluid and electrolytes fast enough to keep most patients stable; those already severely dehydrated need intravenous fluids at a facility. With prompt rehydration, the case fatality rate stays under 1%; without it, cholera is one of the fastest-killing common infections there is.

In India, cholera has long been endemic around the Gangetic delta and eastern India, with case counts historically peaking before and after the monsoon there. Elsewhere it tends to be event-driven — outbreaks following flooding or a specific contaminated source, rather than a steady year-round presence.

Hepatitis and jaundice: usually self-limited, not always

Hepatitis A is a virus, not a bacterium, also spread through water or food contaminated with faecal matter, with a longer incubation than the bacterial diseases here — typically two to six weeks. It starts with fever, fatigue, nausea, and loss of appetite; a few days in, urine darkens and the skin and eyes yellow — the jaundice that gives the disease its common name.

In otherwise healthy people, hepatitis A is self-limiting: it typically resolves within a few weeks without specific treatment, and children often have mild or unnoticeable symptoms, while adults tend to get sicker. Severe, liver-threatening illness is uncommon but real, and people with pre-existing liver disease need closer monitoring.

Worth knowing: a lot of India's water-linked jaundice outbreaks — including several traced to leaking pipelines and contaminated municipal supply — turn out to be hepatitis E, a related but distinct virus, rather than hepatitis A. The transmission route is the same, but hepatitis E is markedly more dangerous in pregnancy, with case fatality in the third trimester cited as high as 20–25%, against well under 1% in the general population. If jaundice appears during pregnancy, that's why it needs medical attention immediately rather than a wait-and-see approach.

Diarrhoeal disease: the biggest number, by a wide margin

Typhoid, cholera, and hepatitis get the dramatic names, but the largest actual disease burden from contaminated water is plain acute diarrhoea — caused by rotavirus, E. coli, Giardia, and a long list of other bacteria, viruses, and parasites, on top of the diarrhoea that typhoid and cholera themselves cause. Globally it remains one of the leading infectious killers of children under five, and India, as the world's most populous country, carries a larger share of that toll than any other single nation.

The frustrating part is that the fix is cheap and well understood: oral rehydration salts plus zinc supplementation prevent the large majority of diarrhoeal deaths, at a cost of well under a dollar per course. Coverage in India still lags what it should be, particularly in rural and lower-income households. India's rotavirus vaccine, folded into the Universal Immunisation Programme since 2016, is a genuine win against one major cause, though it doesn't touch the bacterial and parasitic ones.

Why monsoon concentrates all four

The mechanism is the same one behind municipal water going bad more generally: ageing pipe networks running at intermittent, low pressure sit close to sewer lines, and a drop in pressure can pull sewage in rather than push water out. Heavy rain and flooding make this worse everywhere at once — drains overflow into open wells and shallow sources, tankers may draw from compromised sources during shortages, and runoff carries faecal contamination into supplies that are normally cleaner.

That's why typhoid, cholera, and hepatitis cases, along with routine diarrhoeal disease, track upward through India's monsoon and post-monsoon months almost everywhere they're tracked. None of these diseases is caused by the rain itself; they're caused by rain moving contamination into water that people then drink untreated.

When to stop managing it at home

Most mild diarrhoeal illness resolves with fluids, ORS, and rest. See a doctor rather than waiting it out when any of the following show up:

• Fever above 39°C, or any fever lasting more than 2–3 days without improving
• Signs of dehydration: little or no urination, dry mouth, sunken eyes, dizziness, or unusual lethargy or confusion
• Watery diarrhoea that's unusually frequent or severe, or diarrhoea that doesn't ease within 2 days in a child or 3 in an adult
• Blood in stool or vomit, or an inability to keep any fluids down
• Jaundice (yellow skin or eyes), especially with confusion, severe abdominal pain, or in a pregnant woman
• Any of the above in an infant, an elderly person, someone pregnant, or someone with an existing liver, kidney, or immune condition

The prevention answer doesn't change by disease

Salmonella Typhi, Vibrio cholerae, hepatitis A and E, rotavirus, E. coli, Giardia — every organism here is microbial, not a dissolved chemical, so the treatment problem has one answer: kill or remove the organism before you drink. A rolling boil does that reliably, which is why it remains standard emergency and household advice from public health bodies. Properly maintained filtration or disinfection does the same. What none of this prevents is contamination after treatment — water stored in an unwashed container or handled with unwashed hands can pick the same pathogens right back up, which is worth remembering before assuming a boiled or filtered source stays safe indefinitely.