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The Difference Between Latent TB Infection and TB DiseaseEspañol (Spanish)										Related Pages
										**The Difference Between Latent TB Infection and TB Disease**
**What is TB?**
Tuberculosis (TB) is a disease caused by a germ called *Mycobacterium tuberculosis* that is spread from person to person through the air. TB usually affects the lungs, but it can also affect other parts of the body, such as the brain, the kidneys, or the spine. When a person with infectious TB coughs or sneezes, droplet nuclei containing *M. tuberculosis* are expelled into the air. If another person inhales air containing these droplet nuclei, he or she may become infected. However, not everyone infected with TB bacteria becomes sick. As a result, two TB-related conditions exist: latent TB infection and TB disease.
**What is Latent TB Infection?**
Persons with latent TB infection do not feel sick and do not have any symptoms. They are infected with *M. tuberculosis*, but do not have TB disease. The only sign of TB infection is a positive reaction to the tuberculin skin test or TB blood test. **Persons with latent TB infection are not infectious and cannot spread TB infection to others**.
Overall, without treatment, about 5 to 10% of infected persons will develop TB disease at some time in their lives. About half of those people who develop TB will do so within the first two years of infection. For persons whose immune systems are weak, especially those with HIV infection, the risk of developing TB disease is considerably higher than for persons with normal immune systems.
Of special concern are persons infected by someone with extensively drug-resistant TB (XDR TB) who later develop TB disease; these persons will have XDR TB, not regular TB disease.
A person with latent TB infection
Usually has a skin test or blood test result indicating TB infection
Has a normal chest x-ray and a negative sputum test
Has TB bacteria in his/her body that are alive, but inactive
Does not feel sick,
Cannot spread TB bacteria to others
Needs treatment for latent TB infection to prevent TB disease; however, if exposed and infected by a person with multidrug-resistant TB (MDR TB) or extensively drug-resistant TB (XDR TB), preventive treatment may not be an option**What is TB Disease?**
In some people, TB bacteria overcome the defenses of the immune system and begin to multiply, resulting in the progression from latent TB infection to TB disease. Some people develop TB disease soon after infection, while others develop TB disease later when their immune system becomes weak.
The general symptoms of TB disease include
Unexplained weight loss
Loss of appetite
Night sweats
Fever
Fatigue
ChillsThe symptoms of TB of the lungs include
Coughing for 3 weeks or longer
Hemoptysis (coughing up blood)
Chest painOther symptoms depend on the part of the body that is
affected.
**Persons with TB disease are considered** infectious and may spread TB bacteria to others. If TB disease is suspected, persons should be referred for a complete medical evaluation. If it is determined that a person has TB disease, therapy is given to treat it. TB disease is a serious condition and can lead to death if not treated.
A person with TB disease
Usually has a skin test or blood test result indicating TB infection
May have an abnormal chest x-ray, or positive sputum smear or culture
Has active TB bacteria in his/her body
Usually feels sick and may have symptoms such as coughing, fever, and weight loss
May spread TB bacteria to others
Needs treatment to treat TB disease**Additional Information**
American Thoracic Society (ATS) and CDC. Diagnostic standards and classification of tuberculosis in adults and children. (PDF)*Am J Respir Crit Care Med* 2000; 161.
CDC. Questions and Answers About TB
CDC. Multidrug-Resistant Tuberculosis (MDR TB).
CDC. Extensively Drug-Resistant Tuberculosis (XDR TB).
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						Page last reviewed:  October 20, 2014					Content source: 	Division of Tuberculosis Elimination, National Center for HIV, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention homeTuberculosisBasic TB Factsplus iconHow TB SpreadsLatent TB Infection and TB DiseaseSigns & SymptomsTB Risk FactorsExposure to TBTB PreventionVaccinesTB & HIV CoinfectionTB and DiabetesTB TermsPersonal StoriesTesting & Diagnosisplus iconWho Should be TestedTesting for TB InfectionTesting in BCG-Vaccinated PersonsTB Screening and Testing of Health Care PersonnelTesting During PregnancyDiagnosing latent TB infection and TB diseaseTreatmentplus iconDeciding When to Treat Latent TB InfectionTreatment Regimens for Latent TB Infection (LTBI)Treatment for TB DiseaseAdverse EventsTB Treatment of Persons Living with HIVTB Treatment and PregnancyTB Treatment for ChildrenFrequently Asked QuestionsDrug-Resistant TBResearchplus iconTB Epidemiologic Studies Consortiumplus iconResearch ProjectsPublicationsTB Trials Consortiumplus iconStudy DescriptionsBackgroundBehavioral & Social Science ResearchHealth Care Settingsplus iconTB Infection Control in Health Care SettingsResources for TB Screening and Testing of Health Care Personnelplus iconFrequently Asked QuestionsTB in Specific Populationsplus iconHealth DisparitiesAsian PersonsBlack or African American PersonsHispanic or Latino PersonsChildrenPregnancyCorrectional FacilitiesPeople Experiencing HomelessnessInternational TravelersLaboratory Informationplus iconDrug Susceptibility TestingFalse-Positive Investigation ToolkitInterim Laboratory Biosafety Guidance for XDR  tuberculosis strainsModel Performance Evaluation Program (MPEP)Rapid Molecular Testing to Detect Drug-Resistant TB in the USplus iconExecutive SummaryIntroductionBackground on Tests for Molecular Detection of DRGeneral Considerations and Principles for a Molecular DR Testing ServicePossible Scenarios and Scope of Testing for a Molecular DR Testing ServiceResearch NeedsGeneral Recommendations of the Expert PanelCommunication Plan for the ReportRecommendationsReferencesPanel Members and CDC ParticipantsAppendix 1Appendix 2Appendix 3The Uses of Nucleic Acid Amplification Tests for the Diagnosis of TBplus iconGeneral ConsiderationsGeneral Recommendations of the Expert PanelRecommendations to ACET, CDC, DTBEData & Statisticsplus iconTB Incidence in the United StatesReported TB in the US, 2022 Surveillance Reportplus iconNational DataReporting Area DataRisk FactorsDemographicsTB Treatment and Case OutcomesDrug-Resistant TBMolecular SurveillanceTuberculosis in the United States, 2022 (Slide Set)Archived Surveillance Reports and Slide Sets2021 State and City ReportArchived State and City ReportsProfessional Resources & Toolsplus iconTools for Healthcare ProvidersResources for TB Programsplus iconStrengthening Civil Surgeons’ Capacity to Improve LTBI Surveillance and Outcomes Among Status AdjustersNotice of Funding Opportunity (NOFO)Program EvaluationTB Centers of ExcellenceTB Elimination AllianceTB Genotypingplus iconConventional TB GenotypingWhole Genome SequencingTB GIMSAnalytic ToolsLatent Tuberculosis Infection ResourcesPublications & Productsplus iconPatient and Public MaterialsFact SheetsGuidelinesplus iconControl & EliminationDrug-Resistant TBInfection Control & PreventionLaboratory & GenotypingTB & HIVTB in Specific PopulationsTesting & DiagnosisTreatmentVaccines & ImmunizationsArchived TB GuidelinesGuides & Toolkitsplus iconAggregate ReportsCDC TB Surveillance TrainingCore CurriculumEffective TB Interviewing for Contact InvestigationEthnographic GuidesFalse-Positive Investigation ToolkitForging Partnerships to Eliminate TuberculosisGuide to Application of GenotypingLTBI: A Guide for Primary Health Care ProvidersMantoux Tuberculin Skin Testing ProductsReport of Verified Case of Tuberculosis (RVCT)Self-Study ModulesTB Contact Investigation Interviewing Skills CourseTB eDOT ToolkitUnderstanding the TB Cohort Review ProcessNewslettersplus iconTB Notes, No. 4, 2023TB Notes, No. 3, 2023TB Notes. No. 2, 2023TB Notes. No. 1, 2023TB Notes, No. 4, 2022TB Notes, No. 3, 2022TB Notes, No. 2, 2022TB Notes, No. 1, 2022TB Notes, No. 4, 2021TB Notes, No. 3, 2021TB Notes, No. 2, 2021TB Notes, No. 1, 2021Pamphlets, Brochures, Bookletsplus iconQuestions and AnswersPatient Education SeriesTuberculosis - Get the FactsTuberculosis - The Connection between TB and HIV12-Dose Regimen for Latent TB Infection-Patient Education BrochurePostersplus iconMantoux Tuberculin Skin Test Wall ChartWorld TB DayThink TBStop TBTake on TBReports & Articlesplus iconDTBE Authored Journal ArticlesTuberculosis Laboratory Aggregate ReportsSlide Setsplus iconIntroduction to TuberculosisEpidemiology of Tuberculosis Among Non-U.S.​–Born Persons in the United States, 1993–2016Self-Study Modules on Tuberculosis, 1-5 Slide SetsThe Tuberculosis (TB) in Correctional Settingsplus iconFacilitator GuideIntroduction to TB GenotypingEpidemiology of Tuberculosis in Correctional Facilities, United States, 1993-2017Prevention and Control of Tuberculosis in Correctional and Detention FacilitiesGuidelines for Preventing the Transmission of M. TB in Health care SettingsInvestigation of Contacts of Persons with Infectious TBEpidemiology of Pediatric Tuberculosis in the United StatesTargeted Tuberculosis Testing and Treatment of Latent Tuberculosis InfectionElectronic Tools & ResourcesWeb-Based Courses & Webinarsplus iconTB 101 for Health Care WorkersContent SyndicationInfographicsplus iconSocial Media GraphicsCustomizable Take on TB Infographic with InstructionsEventsWorld TB Dayplus iconU.S. TB ChampionsHistoryFeaturesplus iconTB Risk FactorsTreating Latent TB Infection with Short-Course RegimensWorld Tuberculosis (TB) Day 2021World Tuberculosis (TB) Day 2020Linksplus iconState TB Control OfficesAbout Usplus iconMission Statement and Activitiesplus iconDTBE Strategic PlanNational TB Program ObjectivesOrganization ChartAdvisory Groupsplus iconFederal TB Task Force To receive email updates about this page, enter your email address: Email Address			What's this?				Submit


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