Typhoid Meaning And Definition

Typhoid Meaning And Definition. Typhoid is a serious and sometimes fatal disease spread through contaminated food and water. Typhoid causes fever, fatigue, headache, abdominal pain, and diarrhea or constipation.

What is typhoid ?

Typhoid fever is a systemic infection caused by Salmonella Typhi, usually through ingestion of contaminated food or water. The acute illness is characterized by prolonged fever, headache, nausea, loss of appetite, and constipation or sometimes diarrhoea. Symptoms are often non-specific and clinically non-distinguishable from other febrile illnesses. However, clinical severity varies and severe cases may lead to serious complications or even death. It occurs predominantly in association with poor sanitation and lack of clean drinking water. According to the most recent estimates, between 11 and 21 million cases and 128 000 to 161 000 typhoid-related deaths occur annually worldwide. A similar but often less severe disease, paratyphoid fever, is caused by Salmonella Paratyphi A and B (or uncommonly Paratyphi C).

Who can get typhoid ?

Any person who ingests typhoid organisms, and who is not immune can get typhoid. Children acquire typhoid more frequently than adults. Because typhoid isspread by faecoral contact, or through contaminated food or water, persons who have typhoid may spread typhoid to others if sanitation is poor.Chronic carriers of typhoid, especially those who are food-handlers, may be responsible for ongoing typhoid transmission.

How is typhoid transmitted ?

Typhoid is spread via faeco-oral transmission. The infective dose (the minimum number of organisms required to cause infection) is relatively high at around 100,000 organisms. Typhoid may be spread from person-to-person by direct contact, or through ingestionof contaminated food or water. Infection becomes apparent after an incubation period of 10-14 days (range 5-21 days).

What are the signs and symptoms oftyphoid ?

Typhoid feve ris asystemic illness characterised by: 

1. Fever that is intermittent during the first week, but becomes sustained (lasting > 48 hours) thereafter; 
2. Headache (43-90%),
3. Gastrointestinal symptoms such as abdominal pain/cramps, nausea andvomiting, constipationor diarrhoea. 

Other uncommon clinical signs include a relative bradycardia (a lower heart rate than would be expected in the presence of fever and illness), a skin rash (‘rose spots’ ) which are faint-pink spots 2-4 cm in diameter which develop on the chest, abdomen and back, hepatosplenomegaly (enlarged liver and spleen. The symptoms of typhoid overlap with a number of other infectious diseases important in the region notably malaria. Malaria must be considered first in all persons residing in or with a history of travel to malaria transmission areas who present with fever or a ‘flu-like‘ illness. Since malaria is rapidly progressive but responds well to early treatment, malaria blood tests must be done as a matter of urgency and treatment provided rapidly.

How is typhoid diagnosed ?

Typhoid is diagnosed when Salmonella Typhi is identified in a culture of blood, bone marrow, stool or other tissue. Stool cultures may only become positive after the first week of illness. Ideally, blood and stool cultures should be submitted simultaneously. Culture of bone marrow is useful as it may remain positive even after 5 days of antibiotic treatment. Positive cultures are confirmed by agglutination with specific typhoid anti-sera, including the Vi antigen. The Widal test which looks for antibodies to S. Typhi may be suggestive of the diagnosis but not confirmatory. The Widal test also does not supply information on antibiotic resistance, which is important to guide treatment.

How can typhoid beprevented ?

The three most effective methods of preventing typhoid are: adherence tostrict hand washing with soap and water after using the toilet and before handling food; the provision of safe water, and adequate sanitation. Patients with typhoid fever should pay strict attention to hand hygiene and should not be involved in food preparation until they have been shown to be free of infection.

Three typhoid vaccines are currently recommended for use by:

1. An injectable typhoid conjugate vaccine (TCV), consisting of Vi polysaccharide antigen linked to tetanus toxoid protein licensed for children from 6 months of age and adults up to 45 years of age;
2. An injectable unconjugated polysaccharide vaccine based on the purified Vi antigen (known as Vi-PS vaccine) for persons aged two years and above; and
3. An oral live attenuated Ty21a vaccine in capsule formulation for those over six years of age.

WHO recommends vaccination to control endemic typhoid fever and for outbreak control. Among the available typhoid vaccines, TCV is preferred at all ages in view of its improved immunological properties, suitability for use in younger children and expected longer duration of protection. WHO further recommends that all typhoid fever vaccination programmes should be implemented in the context of other efforts to control the disease, including health education, water quality and sanitation improvements, and training of health professionals in diagnosis and treatment.

Source

https://www.who.int/immunization/diseases/typhoid/en/

http://www.coalitionagainsttyphoid.org/why-typhoid/