Typhoid fever is a life-threatening infection caused by the bacterium Salmonella Typhi. It is usually spread through contaminated food or water. Once Salmonella Typhi bacteria are ingested, they multiply and spread into the bloodstream.
Salmonella typhi is a Gram-negative, obligate anaerobe that belongs to the serogroup D within subspecies I of the genus Salmonella, and it is represented by the antigenic formula 9,12:d:–. Characteristics of S. typhi are both genotypically and phenotypically similar to the genus Salmonella. It, however, displays distinctly different reactions for a number of biochemical tests that normally are used for the characterization of Salmonella spp.
Urbanization and climate change have the potential to increase the global burden of typhoid. In addition, increasing resistance to antibiotic treatment is making it easier for typhoid to spread in communities that lack access to safe drinking water or adequate sanitation.
Epidemiology :-
Improved living conditions and the introduction of antibiotics resulted in a drastic reduction of typhoid fever morbidity and mortality in industrialized countries. However, the disease continues to be a public health problem in many developing areas of the WHO African, Eastern Mediterranean, South-East Asia and Western Pacific Regions.
As of 2019 estimates, there are 9 million cases of typhoid fever annually, resulting in about 110 000 deaths per year.
Typhoid risk is higher in populations that lack access to safe water and adequate sanitation, and children are at highest risk.
Symptoms :-
Typhoid fever gets its name from a high fever that can last for weeks if left untreated. It often gets progressively worse over a few days.
Other symptoms of typhoid fever include:
-Headache.
-Chills.
-Loss of appetite.
-Stomach (abdominal) pain.
-“Rose spots” rash, or faint pink spots, usually on your chest or stomach.
-Cough.
-Muscle aches.
-Nausea, vomiting.
-Diarrhea or constipation.
Stages :-
You can develop symptoms of typhoid fever gradually in four stages. Early treatment with antibiotics can keep you from progressing to later stages.
Stage 1. You can start getting typhoid symptoms anywhere from five to 14 days after coming in contact with S. Typhi. The first symptom is a fever that gets higher over a few days — called “stepwise” since it goes up in steps. The bacteria is moving into your blood in this stage.
Stage 2. Around the second week of fever, the bacteria is multiplying in your Peyer’s patches (part of your immune system that identifies harmful invaders). You’ll start experiencing abdominal pain and other stomach symptoms, like diarrhea or constipation. You might get “rose spots,” small pink dots on your skin that look like a rash.
Stage 3. If not treated with antibiotics, the bacteria can cause severe damage, usually around the third week after your symptoms start. Some people get serious complications, like internal bleeding and encephalitis (inflammation in your brain).
Stage 4. Stage four is when most people begin to recover. Your high fever begins to come down. S. Typhi can live in your gallbladder without causing symptoms, which means you may still be contagious even after you feel better.
Tests :-
Your healthcare provider will take samples of body fluids or tissue to test for signs of S. Typhi. They might take samples of your:
Blood : Your provider will use a needle to take a small tube of blood from your arm.
Stool : Your healthcare provider will give you a sterile container and instructions on how to collect a sample.
Urine : You may be asked to pee into a cup given to you by your healthcare provider.
Your provider might numb your skin and take a sample with a small razor or scalpel.
Bone marrow : Your provider will numb your skin and use a special needle to get a sample of the inside of your bones. It’s rare that you’d ever need this test for diagnosis.
You provider may also take X-rays to look for changes in your lungs.
Prevention :-
Typhoid fever is common in places with poor sanitation and a lack of safe drinking water. Access to safe water and adequate sanitation, hygiene among food handlers and typhoid vaccination are all effective in preventing typhoid fever.
Typhoid conjugate vaccine, consisting of the purified Vi antigen linked to a carrier protein, is given as a single injectable dose in children from 6 months of age and in adults up to 45 years or 65 years (depending on the vaccine).
Two additional vaccines have been used for many years in older children and adults at risk of typhoid, including travellers. These vaccines do not provide long-lasting immunity (requiring repeat or booster doses) and are not approved for children younger than 2 years old:
an injectable vaccine based on the purified antigen for people aged 2 years and above; and
a live attenuated oral vaccine in capsule formulation for people aged over 6 years.
Two typhoid conjugate vaccines have been prequalified by WHO since December 2017 and are being introduced into childhood immunization programmes in typhoid endemic countries.
All travellers to endemic areas are at potential risk of typhoid fever, although the risk is generally low in tourist and business centres where standards of accommodation, sanitation and food hygiene are high. Typhoid fever vaccination should be offered to travellers to destinations where the risk of typhoid fever is high.
The following recommendations will help ensure safety while travelling:-
-Ensure food is properly cooked and still hot when served.
-Avoid raw milk and products made from raw milk. Drink only pasteurized or boiled milk.
-Avoid ice unless it is made from safe water.
-When the safety of drinking water is questionable, boil it, or if this is not possible, disinfect it with a reliable, slow-release disinfectant agent (usually available at pharmacies).
-Wash hands thoroughly and frequently using soap, in particular after contact with pets or farm animals, or after having been to the toilet.
-Wash fruits and vegetables carefully, particularly if they are eaten raw. If possible, vegetables and fruits should be peeled.
Treatment :-
Typhoid fever can be treated with antibiotics. Antimicrobial resistance is common with likelihood of more complicated and expensive treatment options required in the most affected regions.
Your healthcare provider will treat typhoid fever with antibiotics, which may include:
-Ciprofloxacin, levoflaxin or ofloxacin.
-Ceftriaxone, cefotaxime or cefixime.
-Azithromycin.
-Carbapenems.
-If your case is severe, you may be treated with steroids, like dexamethasone.
Even when the symptoms go away, people may still be carrying typhoid bacteria, meaning they can spread it to others, through shedding of bacteria in their faeces.
It is important for people being treated for typhoid fever to do the following:
-Take prescribed antibiotics for as long as the doctor has prescribed.
-Wash their hands with soap and water after using the bathroom and avoid preparing or serving food for other people. This will lower the chance of passing the infection on to someone else.
-Have their doctor test to ensure that no Salmonella Typhi bacteria remain in their body.