The majority of bacteria are opportunists; they will seize any opportunity. Typhi Salmonella is distinct. It only targets humans, has done so for centuries, and still manages to surprise the medical community with its quiet, methodical efficiency.
The bacterium that causes typhoid fever, which is still pervasive in the modern world, is Salmonella Typhi. According to WHO estimates, it causes more than 11 million illnesses every year. Every year, about 135,000 people pass away from it. When you read those figures in a report, they seem to lose their significance, but they shouldn’t.
The bacteria can enter the body through contaminated food or water, such as produce that has been irrigated with untreated wastewater, a meal prepared by someone who unintentionally carries the infection, or a drink from an unsafe source. Unlike many foodborne pathogens, S. Typhi does not remain in the gut once it has entered. It breaks through the intestinal lining, gets into the blood, and starts to spread throughout the body. It is far more dangerous than regular food poisoning because of this.
The onset of symptoms is frequently gradual. a persistent fever, headaches, exhaustion, and appetite loss. Some patients experience faint rose-colored patches on their abdomen or chest. Typhoid and other feverish illnesses, such as dengue, malaria, and viral infections, are often confused. In areas with limited diagnostic laboratories, this confusion can cost weeks of vital treatment time. Death rates can rise to 20% in the absence of antibiotics. Early treatment significantly reduces that percentage to less than 1%. Access is what separates those two figures.
It’s possible that the environment that typhoid takes advantage of, rather than the bacteria itself, is what makes it so dangerous today. The disease is most prevalent in heavily populated regions of South Asia, sub-Saharan Africa, and some parts of Latin America, where drinking water is not always reliable and sanitation infrastructure is still unreliable. India and Pakistan bear a large portion of the world’s burden. Children are disproportionately impacted.
Researchers have been increasingly concerned about the emergence of drug-resistant strains. A few antibiotics, including ampicillin, trimethoprim-sulfamethoxazole, and chloramphenicol, were used to treat typhoid for decades. Subsequently, strains that were resistant to multiple drugs surfaced; these strains had accumulated antibiotic resistance genes in a manner similar to how a virus accumulates mutations.
By handling food, not washing their hands properly, or drinking tainted water, these carriers can silently spread the bacteria to other people. The most famous historical example is Mary Mallon, the notorious “Typhoid Mary” of early 20th-century New York, but she was by no means exceptional. Even when treatment is available, eliminating typhoid in endemic areas is extremely challenging due in part to the carrier dynamic.
Not to be overlooked is a more recent issue. Chronic S. Typhi carriage, especially in the gallbladder, has been associated in some studies with an increased risk of gallbladder cancer. The bacteria seem to produce toxins that can harm DNA and disrupt regular cell cycles, though the exact mechanism is unknown. The long-term effects of typhoid infection may go far beyond the acute illness, according to ongoing research in this area.
There are vaccines, and they are effective. An injectable polysaccharide vaccine and an oral live-attenuated vaccine are two commonly used formulations. A more recent conjugate vaccine is becoming more and more advised for travel to high-risk areas because it has demonstrated stronger immune responses in young children. The science is not the issue. In order to incorporate vaccination into regular immunization programs in the areas where it is most needed, deployment, cost, and political will are necessary.
Observing how typhoid fever is covered—or, more frequently, not covered—gives the impression that the illness benefits from an invisibility that comes with aging. People believe it’s a solved issue because it’s been around long enough. It isn’t.
