Every year, there are approximately 27 million cases of typhoid and 190,000 deaths caused by the disease. Research has shown that the impact of typhoid in developing communities goes beyond physical illness and death. Typhoid infections can cause adverse pregnancy outcomes, impair physical and cognitive development, impact school attendance and performance, and limit productivity in the workforce.
Typhoid is a bacterial infection in humans caused by the bacteria Salmonella enterica serotype Typhi (S. Typhi). Humans, once infected with typhoid, carry the bacteria in their bloodstream and intestinal tract, subsequently shedding it in the stool. A person contracts typhoid through the consumption of food or beverages that have been handled by a person who is shedding S. Typhi or if sewage contaminated with S. Typhi taints water used for drinking or washing food.
Typhoid is found mostly in countries and communities where many people lack access to clean water and basic sanitation, thereby exposing them to the conditions that enable typhoid to spread. Currently, one-third of the world’s population is at risk of contracting typhoid fever, and the infection remains a very real threat in developing countries.
The Coalition against Typhoid Secretariat and CaT members are currently conducting research in Africa and Asia and the Pacific Islands to assess the disease burden and impact of typhoid.
Read more about typhoid through recent publications.
While typhoid fever has more name recognition than paratyphoid, the prevalence of paratyphoid from S. Paratyphi A is increasing in South and Southeast Asia, sub-Saharan Africa, and other parts of the world. The Centers for Disease Control and Prevention (CDC) estimates that 6 million cases of paratyphoid occur each year.
Paratyphoid is caused by an infection by the bacterium Salmonella enterica serotype Paratyphi A, B (tartrate negative), or C (S. Paratyphi A, B (tartrate negative), or C) and is passed to humans or animals through water and food contamination. Currently there are no vaccines available to prevent paratyphoid fever, although there are conjugate vaccine candidates under development for paratyphoid fever alone, and as combination vaccines for typhoid and paratyphoid.
Read more about paratyphoid through recent publications.
Non-typhoidal Salmonella (NTS)
Non-typhoidal salmonellae are a leading cause of bacterial diarrhea worldwide. According to the CDC, they are estimated to cause 94 million cases of gastroenteritis (vomiting and diarrhea) and 155,000 deaths globally each year. Non-typhoidal Salmonellosis (NTS) refers to illnesses caused by all serotypes of Salmonella except for Typhi, Paratyphi A, Paratyphi B (tartrate negative), and Paratyphi C. There are hundreds of NTS serovars that may cause invasive non-typhoidal Salmonella (iNTS) infection in humans, however Typhimurium and Enteritidis are most common. These illnesses are not limited to human hosts.
In particular, iNTS is a major cause of bloodstream infection in sub-Saharan Africa among young children suffering from malaria and malnutrition, and HIV positive adults. Much like typhoid and paratyphoid, those with iNTS show do not have distinctive symptoms, making proper diagnosis and treatment a challenge. Case fatality from iNTS in African adults and children is 20 – 25 percent. Currently there are no vaccines for iNTS, but research for a broad spectrum NTS vaccine is underway.
Read more about NTS through recent publications.
Photos by Mithila Jariwala.