Blood and bone marrow cultures are the current gold standard tests for typhoid diagnosis. These tests are expensive and require equipment that is not routinely available in many low- and middle-income settings with a high burden of typhoid. The above estimates come from the Global Burden of Disease study, which uses models to estimate global disease burden numbers.
Varying burden estimates from different sources, using different modeling methods, range from 11 to 21 million cases and , to , deaths per year. Typhoid is an enteric fever and cannot be clinically distinguished from other enteric fevers caused by Salmonella enterica serovar Paratyphi. Together, the S. Typhi and S. Non-typhoidal Salmonella serovars can cause a serious bloodborne disease known as invasive nontyphoidal Salmonella [iNTS] and diarrheal disease.
It may be difficult to clinically distinguish iNTS from the enteric fevers. Current trends of drug resistance, climate change, and urbanization heighten the risk for typhoid outbreaks worldwide.
Because of increased travel and transient populations, even countries that currently have little or no typhoid burden may become susceptible.
Typhoid is spread by the fecal-oral route through contaminated food and water, usually due to unsafe water, inadequate sanitation, and poor hygiene habits. This puts low-resource communities in low-income countries at the highest risk for typhoid. Since first appearing in the s, multidrug-resistant typhoid—specifically defined as resistance to chloramphenicol, ampicillin, and co-trimoxazole—has since spread globally. During the past 30 years, a multidrug-resistant typhoid strain called H58 has emerged and spread in many parts of Asia and sub-Saharan Africa, displacing other typhoid strains and significantly changing typhoid epidemiology.
In addition to multidrug resistance, this strain has also shown reduced fluoroquinolone susceptibility. Resistance to fluoroquinolones, the drug of choice to treat multidrug-resistant typhoid since the s, and to some third-generation cephalosporins is increasingly frequent, making them less suitable for use in low- and middle-income countries.
Extensively drug-resistant XDR typhoid has emerged in Pakistan, which is responsible for an outbreak that has been ongoing since These strains are resistant to five classes of antibiotics, leaving only one effective oral antibiotic for treatment. Since , more than 10, people have been diagnosed with XDR typhoid. Almost half of urban residents in sub-Saharan Africa and Asia suffer from at least one disease caused by a lack of clean water and sanitation.
Typhoid complications include a life-threatening tear of the small intestines, hepatitis, neuropsychiatric dysfunction, and secondary infections of the lungs and heart.
In Bangladesh, the cost of a single case of typhoid is typically double what the average family spends on health in a year. Drug-resistant typhoid, which is spreading globally, forces the use of more expensive treatment options, further burdening families. Recovery from typhoid can take weeks to months, many times requiring caregivers to miss work to take care of an ill child. The best way to take on typhoid is through an integrated prevention and treatment approach including vaccines, improvements in safe WASH, availability of dependable typhoid diagnostics, and appropriate antibiotics.
Because typhoid is spread via the fecal-oral route, the bacteria can pass to humans through food and water that have been contaminated with fecal matter. Contaminated water and passion fruit juice sold in public markets in Uganda caused a large typhoid outbreak in Water treatment products and education about avoiding untreated beverages were an important part of outbreak control.
Compared to the previous vaccines, TCVs provide longer-lasting protection, only require one dose, and are suitable for children younger than two years of age, allowing delivery through routine childhood immunization programs. Pre- and post-licensure clinical trials with Typbar-TCV as well as post-marketing surveillance of approximately 8 million doses administered in the private sector in India have reported no significant safety signals or serious adverse events related to the vaccine.
Pakistan began introduction of TCV in Sindh Province in November , with nearly 10 million children vaccinated during a three-week campaign. Notably, no eligible studies were identified from Oceania despite the major typhoid fever problem that is recognized in some Pacific islands [ 75 ].
Studies were also lacking from high-income countries, that rely on robust national surveillance systems to monitor typhoid fever. However, typhoid fever incidence is almost universally low in high-income countries, is often travel-associated, and likely contributes little to total global cases [ 76 ].
While increasingly sophisticated approaches to modeling typhoid fever incidence provide a means of estimating typhoid fever incidence in locations where data are lacking [ 2 , 19 , 20 ], we sought to focus on systematic presentation of primary data and summary values across eligible studies. Our quality assessment identified a number of concerns with published typhoid fever incidence studies. We rated 5 studies as high quality, thus classifying the majority as of moderate or low quality.
Our data were also limited by the significant heterogeneity, but given the variation in location, inclusion ages, study design, and dates, this was to be expected. Our search strategy may not have identified negative studies from sites with low typhoid incidence.
A number of factors drove downgrading of study quality. Multiplier studies have been increasingly used to estimate typhoid fever incidence for cost and logistical reasons in recent years [ 48 ]. Such studies are less expensive and less logistically complex than population-based active surveillance studies and underpin considerable recent progress in available typhoid fever incidence data.
However, the multiplier method has not been validated in the context of population-based surveillance and is associated with greater uncertainty introduced at each stage of correction for underascertainment. Furthermore, we identified considerable variation in the types of multipliers that were used. We recommend that consensus be reached on standardization of multiplier selection for future work to ensure that incidence estimates derived from multiplier studies are directly comparable.
We also found that patient selection may have introduced bias in a large number of studies. The control arms of vaccine trials remain an important source of data on typhoid fever incidence. However, it must be recognized that vaccine trials are likely to be preferentially done in areas of high typhoid incidence to increase statistical power.
Furthermore, a number of studies were done in specific age groups or communities, and resulting incidence estimates may not reflect disease in all age groups or the wider population. We also identified variation in who received blood or bone marrow cultures in studies, which may have introduced bias, and blood culture volume adequacy and the proportion of blood cultures contaminated were rarely reported.
While there are concerns for bias, we describe an overall pattern of declining incidence among included studies, with variation in typhoid incidence between surveillance years at the same site and also variation in place within countries and regions. These observations support the recognition of heterogeneity in endemic typhoid fever in both time and place. We encourage ongoing efforts to generate more contemporary estimates of typhoid incidence, focusing on areas and regions where data are lacking, including Oceania and many parts of Africa.
We also identify the need to develop a consensus standard on the types of adjustments that should be made in multiplier studies. This systematic review serves as a resource for site selection for future incidence studies, as a data source for typhoid fever modeling efforts, and in policy decisions for typhoid fever control.
Supplementary materials are available at Clinical Infectious Diseases online. Consisting of data provided by the authors to benefit the reader, the posted materials are not copyedited and are the sole responsibility of the authors, so questions or comments should be addressed to the corresponding author.
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Bull World Health Organ ; 84 : 72 — 7. Typhoid vaccine is recommended for most people travelling to developing countries. Anyone travelling to countries where typhoid fever is common should discuss vaccination to prevent typhoid fever infection. Our typhoid vaccination process is as follows:. In some typhoid-endemic countries with poor sanitation, new conjugate typhoid vaccines are now available to prevent typhoid fever.
This formulation is given to adults aged 45 years old down to infants from 6 months of age, offering at least 3 years of protection These typhoid fever vaccines are not yet licensed in Australia. NB: As this is a live vaccine, it is not suitable for the following groups and the injectable form should be given:. The oral typhoid vaccine may be inactivated if taken with some antibiotics and antimalarial medications — check with the prescribing doctor. Also, if the oral cholera vaccine is also prescribed, at least 8 hours should lapse between the 2 vaccine doses.
Booster doses for both typhoid vaccination types, oral and injectable, do not apply. If at continued risk after 3 years or 5 years for the 4-dose oral schedule , the vaccine dose is repeated.
As with all vaccines and medications, there are side effects and there is a small risk of an allergic reaction from a typhoid vaccination. If you require vaccination against typhoid fever, head to a Travelvax clinic near you. Staffed by trained professionals who have access to state-of-the-art equipment, we can help keep you safe on your next trip. Note: Typhoid vaccination is not funded under the National Immunisation Program NIP , nor by states and territories , but may be covered in part by your health fund Extras cover.
Unless you are travelling to a typhoid-prone area overseas, work in the military or a laboratory that works with Salmonella typhi bacteria you generally don't need to be vaccinated in Australia. The effectiveness of the typhoid vaccines wanes over time so if you have had the injectable version and are at risk of the infection, you need a booster every 3 years.
If you had the oral vaccine you need a booster every years depending on initial course of 3 or 4 doses. The main differences are the duration of coverage and the contraindications or precautions for receiving a live vaccine. See above. Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission. This content does not have an English version. This content does not have an Arabic version.
Overview Typhoid fever is caused by Salmonella typhi bacteria. Request an Appointment at Mayo Clinic. Share on: Facebook Twitter. Show references Jameson JL, et al. In: Harrison's Principles of Internal Medicine. McGraw Hill; Accessed Oct.
Ryan ET. Epidemiology, microbiology, clinical manifestations, and diagnosis of typhoid fever. Typhoid fever. Centers for Disease Control and Prevention. World Health Organization.
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