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Typhoid and Paratyphoid (Enteric Fever)

Queensland Health Guidelines for Public Health Units

Revision History

 Version  Date  Changes

 1.0

 1.1

1.2

December 2010

August 2011 

July  2014

Full revision of guideline.

Edited re clearance for cases.  

Full revision of guideline. 

Infectious Agent

Typhoid: Salmonella enterica subsp. enterica serovar Typhi (commonly S. Typhi)

Paratyphoid: Salmonella enterica subsp. enterica serovars Paratyphi - A, B, C (commonly S. Paratyphi A, B and C)

Notification Criteria

Laboratory definitive evidence
Isolation or detection of S. Typhi or S. Paratyphi A, B or C from any clinical specimen.

(Exception: S. Paratyphi B biovar Java does not cause a typhoid-like enteric illness. It causes gastroenteritis and as such is coded as one of the salmonellae.)

Note: national case definition is only for S.Typhi – S. Paratyphi is combined with other Salmonellas.

Community outbreak criteria
Two or more geographically or temporally or epidemiologically linked cases.

Notification Procedure

Pathology Laboratories
To notify on microbiological confirmation by telephone or facsimile.

Lab Aspects

Blood cultures are the standard diagnostic method. A large volume of blood (15mL in adults) improves sensitivity. The sensitivity of blood culture is higher in the first week of illness. Culture of bone marrow is more sensitive than blood culture. The sensitivity of stool culture depends on the amount of faeces cultured and the positivity rate increases with the duration of the illness. Bacterial shedding in stools is irregular.

Reporting to NOCS

Report only confirmed cases.

Confirmed case: A confirmed case requires laboratory definitive evidence.

Objectives of surveillance

  1. To prevent further cases by ensuring adequate restriction and treatment of cases, investigation of contacts and mitigation of local sources.
  2. To monitor the epidemiology of enteric fever in Queensland.

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Public Health Significance and Occurrence

Occurs worldwide. Most of the burden of disease occurs in the developing world.  Outbreaks occur in areas with poor sanitation and inadequate sewerage systems. In Queensland, approximately 10 cases of typhoid/paratyphoid are notified each year, the majority being in returned travellers. Paratyphoid presents a similar clinical picture to typhoid but it is usually milder, shorter in duration and with fewer complications. Of the three serotypes, A is most common, and C extremely rare.

Clinical Features

A systemic bacterial disease with insidious onset of sustained fever, marked headache, malaise, anorexia, relative bradycardia, splenomegaly, non-productive cough in the early stage of the illness, rose spots on the trunk in 25% of white-skinned patients and constipation more often than diarrhoea in adults. The clinical picture varies from mild illness with low-grade fever to severe clinical disease with abdominal discomfort and multiple complications (15% – 20% of patients may experience relapses depending on the antimicrobials used). Case fatality is less than 1% with prompt antibiotic treatment. After beginning antibiotics, symptoms typically abate within four days to a week. Unapparent or mild illnesses particularly occur in endemic areas. Mild cases show no systemic involvement; the clinical picture is of gastroenteritis.

Paratyphoid fever presents a similar clinical picture, but tends to be milder (relapses occur in 3% - 4% of cases).

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Reservoir

Typhoid: Human, especially gallbladder carriers and, rarely, urinary carriers.

Paratyphoid: Human and questionably domestic animals.

Mode of Transmission

Faecal-oral route. Contaminated water and food, rarely by contact. For travellers important sources are water or ice, raw vegetables, salads, raw fruits and shellfish. Sexual transmission of typhoid fever from an asymptomatic carrier has been demonstrated.

Incubation Period

Typhoid: 3 days to over 60 days (inoculum dependent), usually 8 – 14 days.

Paratyphoid: 1 – 10 days.

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Period of Communicability

As long as the bacilli appear in excreta, usually from the first week of illness. Left untreated, about 10% of typhoid fever patients will discharge bacilli for three months after the onset of symptoms and about 2% to 5% become permanent carriers. However, with appropriate treatment, the rate of chronic carriage is extremely low. Fewer people with paratyphoid fever become permanent gallbladder carriers.

Susceptibility and Resistance

Susceptibility is general and is increased in individuals with gastric achlorhydria and possibly those who are HIV-positive.

Relative specific immunity follows recovery from clinical disease, unapparent infection and active immunisation.

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Management

Cases

Investigation
Locally-acquired cases are unusual in developed countries, but the actual or probable source of infection of every case should be determined. In consultation with the attending medical practitioner, obtain a food history and ask questions about recent overseas travel (obtain the date), exposure to someone else known to have travelled overseas recently, or exposure to other known cases/carriers.

Restriction and clearance
Cure is expected for nearly all persons who take appropriate antibiotic therapy, with very low rates of relapse or chronic carriage.  The risk of transmission is low where hygiene practices are good.

However, persons at higher risk of transmitting the disease include food handlers, carers of patients, carers of children, carers of the elderly, those unable to maintain personal hygiene and their carers.

All cases should be excluded from work, school, childcare and swimming pools until 48 hours after resolution of symptoms. All cases should be advised not to cook for others until 48 hours after resolution of their symptoms. 

"High risk" cases as outlined above should further be excluded from high-risk duties until 2 consecutive stool specimens collected one week apart and not sooner than 48 hours post cessation of antibiotics are negative.  They may return to work to undertake other duties (not high risk) once they have been free of symptoms for 48 hours. This includes cases who are chronic carriers.

If a case is in hospital, enteric precautions are indicated.

Treatment
Consult the latest edition of Therapeutic Guidelines: Antibiotic.

Counselling
Good hygiene is the single most effective way of preventing the spread of typhoid. The importance of hand washing, especially after using the toilet and before preparing or handling food must be emphasised and reinforced at each contact with the infected person.

Chronic Carriers

Definition
An asymptomatic person who sheds S. Typhi for more than 12 months.

Treatment
Consult an infectious disease physician. 750mg ciprofloxacin or 400mg norfloxacin twice daily for 28 days successfully treats carriers in 80-90% of cases.

Investigation
Manage chronic carriers the same as others with a positive specimen (ie. faecal clearance and exclusion as above), but also assess gall bladder function and consider cholecystectomy if gallstones present. Investigate the urinary tract if a possible urinary carrier (biliary and urinary stasis are associated with carriage and removal of gallstones or surgery for urinary anomalies can clear the organism).

Contacts

Contact Tracing
Yes.

Definition
Household contacts: those living in the same household as the case and/or those who have shared a bathroom and/or those who have eaten food prepared by the case while they were likely to be infectious.

Travel companions (if the disease was acquired overseas): someone who travelled with the case and who is likely to have been exposed to the same source of infection. 

Investigation
Question household (and travel companions if the disease was likely to have been acquired overseas) about symptoms and assess whether they belong to a "high risk" group as defined under Cases above. 

If the case has not travelled to an endemic country and the results of stool samples from their household contacts (see below) are negative, investigation should expand to question (and possibly request stool samples from) other contacts in attempt to identify the source of infection of the case.  Consider other people in contact with the case in the month prior to illness onset.  Use a risk based approach to guide contact sampling in this instance - consider their travel history and likelihood of transmitting disease to the case based on the nature of contact.

Restriction and screening
A symptomatic contact should be investigated as a possible case. Refer to their medical professional for diagnostic testing (faeces and blood cultures), provide hygiene advice and exclude from work, school, childcare and swimming pools until 48 hours after last symptoms.  If investigations are negative for typhoid / paratyphoid, no further action is required in this respect.

Asymptomatic "high risk" contacts should be excluded from work, school, and childcare until proof of 2 negative stool samples at least 24 hours apart.  If feasible, they may undertake other duties (not high risk) while awaiting specimen results.

Asymptomatic "non-high risk" household contacts of a case who has not travelled to an endemic area should also provide 2 stool samples 24 hours apart.  These contacts do not require exclusion.

Other asymptomatic "non-high risk" contacts do not require stool samples or exclusion.

Counselling
All identifiable contacts should receive information about the disease and mode of transmission and be advised to exclude themselves and present to their medical practitioner should symptoms develop within the next month.  Include education about hygiene, in particular hand-washing before eating and preparing food, and after going to the toilet.

Contact of a chronic carrier
Chronic carriers may continue to excrete while being treated or awaiting clearance.  Chronic carriers may infect others in their household while being treated and followed up, although this is considered unlikely.

Other control measures

Community outbreaks/epidemics

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Preventive Measures

Vaccination

Typhoid vaccination is recommended for all travellers two years of age and over going to endemic regions where food hygiene may be suboptimal and drinking water may not be adequately treated. Travellers include the military. Vaccination should be completed at least two weeks prior to travel.

 Laboratory personnel routinely working with S. Typhi should also be considered for vaccination as should household contacts of chronic carriers.

 Oral and parenteral vaccines are available. See the latest Australian Immunisation Handbook for further information.

Other preventive measures include:

Summary

Prepare a report of the investigation for the Communicable Diseases Unit, Queensland Health, on request.

Complete report form for OzFoodNet.

References

Antibiotic Expert Group. 2006. Therapeutic Guidelines: Antibiotic: version 13. Therapeutic Guidelines Ltd: Melbourne.

Balasegaram S, Potter AL, Grynszpan D, Barlow S, Behrens RH, Lighton L et al. Guidelines for the public health management of typhoid and paratyphoid in England. Journal of Infection; 2012, 65: 197-213.

Bhan MK, Bahl R, Bhatnagar S. 2005. Typhoid and paratyphoid fever. Lancet, 366: 749-62.

Heymann D (Ed).  2008. Control of Communicable Diseases Manual, 19th ed.  American Public Health Association: Washington.

NHMRC (2008) The Australian Immunisation Handbook, 9th ed. NHMRC: Canberra.

Parry CM, Dougan G, White NJ, Farrar JJ. 2002. Typhoid fever. New Eng J Med 347(22):1770-1782.

Skull SA, Tallis G. An evidence-based review of current guidelines for the public health control of typhoid in Australia: a case for simplification and resource savings. Australian & New Zealand Journal of Public Health 2001;25:539-42.

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Last Updated: 07 November 2014
Last Reviewed: 07 November 2014