—from the Epidemiological Bulletin, Vol. 21 No.1, March 2000—
Case definitions:
Neonatal Tetanus and Tuberculosis
Neonatal Tetanus
Rationale for surveillance
Neonatal tetanus was targeted for elimination (9GPW) by WHO. In the American Region, the 3 primary strategies towards this goal are: 1) identification of high risk areas; 2) vaccination of all women of child-bearing age who live in at-risk municipalities; and 3) clean delivery and post-deli- very practices.
Epidemiological surveillance is particularly useful in order to identify high-risk areas and monitor the impact of interventions
Recommended case definition
Suspected case: Any infant with a history of tetanus-compatible illness during the first month of life that fed and cried normally for the first 2 days of life; Or: Any neonatal death (death within the first 28 days after birth) in a child who could suck and cry normally during the first 48 hours of life.
Confirmed case: A confirmed case of neonatal tetanus defined as a child with a history of all three of the following: 1) normal feeding and crying for the first 2 days of life; 2) onset of illness between 3 and 28 days of life; and 3) inability to suck (trismus), followed by stiffness (generalized muscle rigidity) and/or convulsions (muscle spasms).
Discarded Case: A discarded case is one that has been investigated and does not fit the case definition. The diagnosis should be specified. A summary of diagnoses for discarded cases should be made routinely.
Recommended types of surveillance
The number of confirmed neonatal tetanus cases must be included in routine monthly surveillance reports of all countries and reported as a separate item from other (non-neonatal) tetanus. Even if there are no cases, the mention of “zero case” in the report is required, as well as active surveillance in major health facilities on a regular basis (at least once a year). In “low risk” geographical areas (incidence<1/1000 live births with effective surveillance), all suspect cases should be investigated to confirm the case and identify the cause. Community surveillance is recommended in “silent” areas (i.e. where routine reporting is not functional but where, based on socioeconomic indicators, neonatal tetanus could be a problem).
Recommended minimum date elements
Aggregated data for reporting
- Number of cases.
- Number of TT1, TT2 or TT3 doses administered to wo-men of child-bearing age and number of women of child-bearing age who live in the municipality. · Completeness / timeliness of monthly reports.
Case-based data, individual patient records for investigation:
(i) Unique identifier, (ii) Geographical information, (iii) Date of birth, (iv) Age (in days) of infant at onset, (v) Sex of infant, (vi) Parity of mother (total number of deliveries including current delivery or pregnancy), (vii) Date of case investigation, (viii) Type of birth: 1=institution; 2=home with trained attendant; 3=home with untrained attendant; 4=home without attendant; 5=other; 9=unknowm, (ix) Tetanus immunization status of mother when she gave birth: 1=up-to-date; 2=not up-to-date; 3=unimmunized; 9=unknown, (x) Final classification: 1=confirmed; 2=suspected; 3=discarded, (xi) Mother given protective TT dose within 3 months of report: 1=yes; 2=no; 9=unknown, (xii) Supplemental immunization conducted within same locality as case: 1=yes; 2=no; 9=unknown.
Principal use of data for decision-making
- Monitor progress towards achieving and sustaining high routine TT2+ coverage in high-risk areas.
- Monitor progress towards eliminating neonatal tetanus in every geographical area.
- Investigate suspected neonatal tetanus cases in areas not considered at risk for neonatal tetanus to confirm and determine cause.
- Identify high-risk geographical areas and conduct 3 rounds of supplemental TT immunization in those areas.
- Periodically validate sensitivity of neonatal tetanus reporting and surveillance by comparing the number of reported cases with the number of cases identified through active surveillance.
Tuberculosis
Rationale for surveillance
The overall objective of tuberculosis (TB) control is to reduce mortality, morbility and transmission of the disease until it no longer poses a threat to public health. To achieve this objective, the 1991 World Health Assembly endorsed the following targets for global tuberculosis control: successful treatment for 85% of the detected new smear-positive cases and detection for 70% of smear-positive cases by the year 2000.
About one third of the world’s population is infected by Mycobacterium tuberculosis. Between 7 and 8.8 million new cases occur each year, 95% in developing countries; some 3.3 million cases of tuberculosis are notified each year. Projections into the next century suggest that the impact of tuberculosis will increase if no adequate control is established immediately in all countries.
Surveillance of tuberculosis helps obtain an accurate picture of the course of the epidemic in a community over time so as to allow timely intervention.
Recommended case definition:
Pulmonary tuberculosis, sputum smear positive (PTB+):
- Tuberculosis in a patient with at least two initial sputum smear examinations (direct smear microscopy) positive for Acid-Fast Bacilli (AFB), or
- Tuberculosis in a patient with one sputum examination positive for acid-fast bacilli and radiographic abnorma-lities consistent with active pulmonary tuberculosis as determined by the treating medical officer, or
- Tuberculosis in a patient with one sputum specimen positive for acid-fast bacilli and at least one sputum that is culture positive for acid-fast bacilli.
Pulmonary tuberculosis, sputum smear negative (PTB-):
Either: a patient who fulfills all the following criteria:
- two sets (taken at leat 2 weeks apart) of at least two sputum specimens negative for acid-fast bacili on microscopy;
- radiographic abnormalities consistent with pulmonary TB and a lack of clinical response despite one week of a broad-spectrum antibiotic;
- a decision by a physician to treat with a full curative course of anti-TB chemotherapy;
Or: a patient who fulfills all the following criteria:
- severely ill;
- at least two sputum specimens negative for acid-fast bacilli by microscopy;
- radiographic abnormalities consistent with extensive pulmonary TB (interstitial or miliary);
- a decision by a physician to treat with a full curative course of anti-TB chemotherapy;
Or: a patient whose initial sputum smears were negative, who had sputum sent for culture initially, and whose subsequent sputum culture result is positive.
Extra-pulmonary tuberculosis:
- Tuberculosis of organs other than lungs: pleura, lymph nodes, abdomen, genito-urinary tract, skin, joints and bones, tuberculous meningitis, etc.
- Diagnosis should be based on one culture positive specimen from an extra-pulmonary site, or histological or strong clinical evidence consistent with active extra-pulmonary tuberculosis, followed by a decision by a medical officer to treat with a full course of anti-tuberculous therapy.
Note: Any patient diagnosed with both pulmonary and extra-pulmonary tuberculosis should be classified as a case of pulmonary tuberculosis.
New case: A patient who has never had treatment for tuberculosis or took anti-tuberculous drugs for less than 4 weeks.
Relapse case: A patient previously treated for tuberculosis and declared cured by a medical officer after one full course of chemotherapy, but who reports back to the health service bacteriologically positive (smear or culture).
Recommended surveillance measures
Quarterly reports on case notifications and cohort analysis of treatment outcomes (at peripheral, intermediate, and central level).
Recommended minimum data elements
- Number of new pulmonary sputum smear positive cases
- Number of pulmonary relapse cases
- Number of new pulmonary sputum smear negative cases
- Number of new extra-pulmonary cases
- Number of new pulmonary sputum smear positive cases by age and gender (suggested age groups: 0-14, 15-24, 25-34, 35-44, 45-54, 55-64, 65+ years)
Treatment results for new sputum smear positive cases: (usually as a percentage of all new sputum smear positive cases registered during the same period of time):
- Number of cases who converted to negative after initial phase of treatment.
- Number of cases cured (i.e., completed treatment and at least 2 negative sputum smear results during the continuation phase of treatment, one of which occurred at the end of treatment).
- Number of cases who, after smear conversion at the end of initial phase of treatment, completed treatment, but without smear results at the end of treatment.
- Number of cases who died (regardless of cause).
- Number of cases who failed treatment (i.e., became positive again or remained smear positive, 5 months or more after starting treatment).
- Number of cases who interrupted treatment / defaulted (i.e., did not collect drugs for 2 months or more after registration).
- Number of cases who were transferred out (i.e., transferred to another reporting unit and results not known).
Principal uses of data for decision-making
- At local level: ensure that appropriate treatment services are offered, contact tracing is carried out, local outbreaks are recognized, and local epidemiology is monitored.
- At national level: facilitate monitoring of the epidemiology of the disease and of the performance of treatment programmes (ability of a National Tuberculosis Programme to detect tuberculosis cases, diagnose sputum positive cases, treat tuberculosis cases successfully); and facilitate planning for programme activities (e.g., securing drug supply, lab supply, etc.).
- At international level: examine trends over time and make inter-country comparisons with the aim of coordinating control efforts.
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Epidemiological Bulletin, Vol. 21 No.1, March 2000
