What is typhoid?
Typhoid is a bacterial infection caused by Salmonella typhi that spreads through contaminated food and water. The bacteria enter the small intestine and multiply, causing high fever, diarrhea, headaches, rash, and fatigue. Typhoid can be fatal if not treated promptly with antibiotics. Before modern sanitation and antibiotics, typhoid was a major killer, but with improved sanitation and vaccination, typhoid has become rare in industrialized nations. However, it remains endemic in developing regions with poor sanitation and limited access to clean water and healthcare. An estimated 11-20 million cases and 128,000-161,000 deaths from typhoid occur annually worldwide.
How do you get typhoid?
You can get typhoid in two main ways:
- Eating or drinking food or water contaminated with S. typhi. This includes fruits and vegetables grown or washed in contaminated water.
- Close contact with someone infected with S. typhi who sheds the bacteria in their stool or urine. This includes nursing or caring for someone with typhoid fever.
Because S. typhi is shed in stool and occasionally urine, typhoid spreads rapidly in areas with poor sanitation and hygiene. Contaminated sewage can get into water supplies, contaminating public water sources, wells, and food crops irrigated with contaminated water. Flies can spread the bacteria from feces to food. Typhoid is not spread through casual contact, only through ingestion of contaminated food or water.
What are the symptoms of typhoid?
Typhoid symptoms usually appear 1-3 weeks after exposure to the bacteria, although they can take up to 60 days to appear. Symptoms often come on gradually and include:
- High fever – can reach up to 104°F (40°C)
- Fatigue and weakness
- Headaches
- Dry cough
- Abdominal pain and cramping
- Constipation – more common in adults
- Diarrhea – more common in children
- Loss of appetite
- Rash of flat, rose colored spots on the chest and abdomen
Without treatment, the fever comes in waves, rising in the evenings and subsiding in the morning. Other complications can develop in untreated typhoid:
- Gastrointestinal bleeding due to intestinal ulcers
- Perforation of the intestine
- Heart infection (endocarditis)
- Meningitis (inflammation of membranes around the spinal cord and brain)
- Encephalitis (brain inflammation)
- Liver or spleen abscesses
- Pneumonia
Some people can carry S. typhi in their gallbladders, shedding the bacteria in stool intermittently. This condition is known as a typhoid carrier state. Carriers have no symptoms but can still spread the infection.
How is typhoid diagnosed?
If typhoid is suspected based on symptoms, the doctor can order lab tests to confirm the diagnosis:
- Blood culture: Samples of blood are taken to try to grow S. typhi in culture. Blood cultures can confirm diagnosis in 60-90% of people. This test takes 2-5 days for results.
- Stool culture: A sample of stool is analyzed to look for S. typhi. The bacteria can be shed in stool later in the infection.
- Bone marrow culture: The bacteria are sometimes visible in bone marrow. Bone marrow samples are usually only needed if blood and stool cultures are negative.
- Serology tests: Blood is analyzed for the presence of antibodies against the S. typhi bacteria. Antibody levels rise and fall during infection, so timing is important for accuracy.
- Polymerase chain reaction (PCR): This detects S. typhi DNA in blood and can provide rapid diagnosis. It is an accurate test.
Imaging tests like CT scans and ultrasounds may also be done to check for complications like intestinal perforation or abscesses in other organs.
How is typhoid treated?
Typhoid is treated with antibiotics, which can shorten duration of illness and reduce mortality. Treatment also reduces risk of spreading the infection to others.
- Ciprofloxacin has been the antibiotic of choice for uncomplicated typhoid. It is given for 10-14 days.
- Ceftriaxone given IV or IM for 10-14 days is another preferred option.
- Other options include azithromycin for uncomplicated typhoid or ampicillin, trimethoprim-sulfamethoxazole for more severe cases.
Those antibiotics cannot be given in pregnancy. Alternatives in pregnancy include azithromycin and third-generation cephalosporins.
Some S. typhi strains have developed antibiotic resistance. Multidrug resistant (MDR) strains are common in South Asia. These require treatment with carbapenems or azithromycin.
Treating complications may require surgical drainage of abscesses or repairing intestinal perforations. Supportive treatment like IV fluids and electrolyte management are also important.
Most people recover completely with antibiotics, but fatigue and weakness may persist for a month or more. Relapse occurs in 10-15% of people and long-term carrier state in 2-5%. Fatality rate with treatment is around 1%.
Treatment in resource-poor regions
In regions with limited healthcare access, diagnosis may rely more on clinical symptoms than lab tests. Treatment options may also be constrained by lack of available antibiotics or high rates of antibiotic resistance. Oral rehydration solutions can help combat dehydration and electrolyte abnormalities. Preventative strategies like vaccination and hygiene improvements are especially important in those settings.
Can you get typhoid again after being cured?
Yes, it is possible to get typhoid again after recovering fully and being cured with antibiotics. This occurs because typhoid does not result in lifetime immunity.
After infection, the immune system develops antibodies against S. typhi. Immunity after infection or vaccination wanes over time. One estimate is that immunity lasts around 7 years on average after natural infection. But some people become susceptible again sooner while others retain immunity longer.
Reinfection is more common in areas with high rates of typhoid exposure from contaminated food and water supplies. Individuals with past infection or vaccination may have milder symptoms on reinfection. But they can still develop serious illness, complications, and transmit S. typhi to others.
Additionally, antibiotic treatment does not always fully eliminate S. typhi bacteria from the body. A small percentage of people go on to become chronic, long-term carriers after infection. The bacteria remain living in the biliary system or other sites and these individuals continue shedding the bacteria in their stool or urine. Carriers are at risk for relapse and can be a source of new infections in the community.
Can typhoid be prevented with vaccination?
Yes, vaccination helps prevent typhoid by stimulating immunity against S. typhi. Two typhoid vaccines are commonly used:
- Ty21a oral vaccine: This live, attenuated vaccine is given in 4 capsules taken every other day. It provides 50-80% protection that begins to wane after 5-7 years.
- Vi polysaccharide vaccine: This injectable vaccine contains purified Vi capsular polysaccharide from S. typhi. It provides 65-75% protection that wanes after 3 years.
Newer typhoid conjugate vaccines (TCVs) have been developed that provide longer-lasting immunity and can be given to young children. The World Health Organization recommends routine TCV immunization where typhoid risk is high. Vaccination is recommended for:
- Travelers to areas with endemic typhoid
- Household contacts of known S. typhi carriers
- Populations in endemic areas, especially children
Vaccination provides protection against infection, but is not 100% effective. Individual response and waning immunity over time make reinfection possible. Vigilance with food, water safety, and hand hygiene remains important. Targeted vaccination programs, alongside improvements in water quality, sanitation, and hygiene, are critical for controlling typhoid long-term.
What progress has been made in typhoid control?
Typhoid has been drastically reduced in incidence and mortality in the last century in countries that have improved water sanitation, hygiene practices, and access to healthcare and antibiotics. Typhoid incidence in the U.S. has declined from over 35 cases per 100,000 people in 1920 to less than 300 cases reported nationwide in 2017. Still the progress has not been uniform across the globe. For example:
| Country | Estimated typhoid incidence (cases/100,000 population per year) |
|---|---|
| United States | 0.1 |
| Bangladesh | 214 |
| India | 188 |
| Pakistan | 412 |
Key measures that have successfully controlled typhoid historically and remain priorities in high-burden regions include:
- Closing the fecal-oral transmission route through improved water quality, sanitation, and hygiene (WASH). This breaks the cycle of bacteria passing from feces to water/food sources and then to new hosts.
- Targeted vaccination of populations at high risk with newer TCVs that give longer-lasting protection.
- Surveillance programs and rapid diagnostic tests to identify outbreaks and carriers.
- Public education campaigns promoting handwashing, safe food handling, and typhoid awareness.
- Training programs and infrastructure investments that increase access to healthcare and effective antibiotics.
Challenges remaining
Despite progress, major challenges hinder typhoid control efforts:
- Limited access to clean water and sanitation facilities in impoverished urban and rural areas.
- Ongoing conflicts and crises disrupting vaccination programs.
- Lack of healthcare investment in marginalized communities.
- Antibiotic overuse and misuse accelerating S. typhi drug resistance.
- Poverty, lack of education, and inadequate policies failing to stop fecal contamination of water supplies.
- Weak surveillance and reporting systems missing typhoid cases and outbreaks.
Targeted investment, political will, community engagement, and integrated control strategies will be needed to make further headway against typhoid.
Conclusion
Typhoid remains a serious public health threat in many low and middle-income regions, but proven strategies exist to reduce its toll. Vaccination, infrastructure upgrades, public education, surveillance, and access to medical care combine to save lives and decrease typhoid incidence long-term. Total eradication is difficult given S. typhi’s niche in only humans, asymptomatic carriers, recurring susceptibility after illness or vaccination, and socioeconomic factors enabling transmission. Continued efforts targeting high-risk areas while decisions makers keep typhoid impact in focus will bring the world closer to boxing in typhoid for good.