EPI-NEWS NATIONAL SURVEILLANCE OF COMMUNICABLE DISEASES Editor: Tove Rønne Statens Serum Institut - 5 Artillerivej - 2300 S - Tel.: +45 3268 3268 - Fax: +45 3268 3868 www.ssi.dk - [email protected] - ISSN: 1396-4798

OUTBREAK OF TUBERCULOSIS No. 1-2, 2001 Investigation of a case of tuberculo- desinfected by washing all horizon- bacteria shows the same DNA re- sis (TB) in a young Danish national tal surfaces, bunks and cupboards striction fragment length pattern, serviceman has so far revealed two with a chlorinated compound. Mat- also called “DNA fingerprint”, further cases of TB. 14 of 37 persons tresses, curtains and cleaning rags Fig. 1, the patients are usually mem- examined at the barracks were Man- were destroyed. bers of the same chain of . toux positive, which is unusual for On the other hand, if the fingerprints Danish conditions. Comment are different, it is most unlikely that TB is still a serious disease. Although the patients belong to the same chain Tuberculosis in Næstved Barracks only a few hundred persons per year of infection. In August 2000 open pulmonary TB are infected by TB in Denmark , it is Fig. 1. Identical M. tuberculosis was diagnosed in a national service- important to consider this diagnosis DNA pattern from patients A and B man at the South Zealand military in patients with prolonged cough or installations at Næstved. Initial di- unexplained tiredness.

164 agnosis was by chest x-ray, followed (F. Juhl, Næstved Central Hosp., 176 171 182 200 by the observation of massive num- O. Mygind, MOH, Storstrøm County) 206 bers of acid-fast bacilli on sputum 268 microscopy. The patient had sought Blood test for tuberculosis 274 303 309 324 medical advice because he had been An immunological method for de- 331 354 363 362 coughing for six months, latterly with tecting TB infection is under deve- 369 388 396 402 green sputum, and was now unable lopment. It is based on a blood test 409 to keep up with others on training for demonstrating the presence of runs. The patient belonged to a de- circulating, antigen-specific T cells

523 tachment of 38 persons between 19 that arise as a result of the infection. 530 and 25 years of age, divided into two These cells liberate the proinflam- equal squads that were quartered in matory cytokine interferon-g when By means of these DNA methods one dormitories of 10 bunk beds separa- stimulated in vitro by M. tuberculo- can also assess whether patients who ted by 165 cm. In tracing the spread sis-specific antigens. In earlier trials develop TB on successive occasions of infection the local Medical Officer the test has shown a specificity of have been reinfected by a new bac- of Health defined a group of close over 95% and a sensitivity of about terial strain or whether there has contacts to be investigated. This 75-80%. In future it may prove to be been a reactivation of the earlier group included all members of the a useful supplement to present diag- infection. In the Næstved TB out- detachment plus two NCO’s who had nostic methods. The test has several break described, it was demon- been in particularly close contact advantages, including independence strated that the two persons who de- with the patient. The investigation of BCG vaccination status and expo- veloped TB at the barracks had been protocol was designed in accordance sure to non-pathogenic mycobacte- infected by bacteria of identical with National Board of Health ria, and can also detect extrapulmo- DNA pattern, Fig. 1. DNA analysis of guidelines for family contacts. This nary TB and subclinical . In the isolate from the one-year-old involved Mantoux testing of a total connection with the outbreak descri- child has not yet been completed. In of 37 of the 39 persons in the contact bed above, all 39 members of the future it will be possible to deter- group, as two of these had been BCG close contact group were asked to mine whether other persons infected vaccinated. Altogether 14 persons give a blood test, 21 of these consent- at the barracks develop TB of the were Mantoux positive: 100% of ing (six Mantoux positive, 13 nega- same DNA pattern, even if this takes those sharing the patient’s 10-bunk tive, one with an uncertain reaction place after several years as a result dormitory and 40% of those in the and one previously BCG vaccinated). of reactivation. adjacent dormitory, as well as 5% There was a reaction to the specific (T. Lillebæk, Å.B. Andersen, Int. Ref. (one member) of the other squad. antigens in specimens from six per- Laboratory for Mycobacteriology) Subsequent chest x-ray showed that sons. The test method showed good one person sharing the patient’s general agreement with Mantoux INFLUENZA dormitory had lung changes com- testing. Further evaluation of the In week 51 of 2000 an influenza A patible with TB, and further investi- method is under way. (H3N2)/Moscow-like strain was gation revealed that this person also (I. Brock, P. Andersen, Dept. of TB isolated from a clinical specimen. In had infectious TB. A parallel investi- Immunology) week 52 an influenza A (H1N1)/ gation of the index patient’s family New Caledonia-like strain was iso- showed that a child just over 1 year DNA analysis in tuberculosis lated from a sentinel specimen. Both old had also developed TB. Because During the last decade it has been strains are included in this season’s of their massive exposure and close possible to perform a DNA-based influenza and are in line contact, all the Mantoux-positive identification of TB isolates from in- with strains detected elsewhere in persons were offered prophylactic dividual patients. In this way it is Europe. treatment with isoniazid 300 mg possible to determine whether the (P.C. Grauballe, Dept. of Virology, daily and pyridoxine 50 mg x 1-2 bacterium that has infected patient S. Samuelsson, Dept. of Epidemiol.) daily for 6 months. Once the de- A is identical to or different from that tachment had left, the dormitory was which has infected patient B. If the 10 January 2001 Patients with laboratory-diagnosed RSV or rotavirus infections, 2000

September October November RSV Rota RSV Rota RSV Rota

0 7 4 5 13 10

Reported from the following Clinical Microbiology Departments: Aalborg Hospital (South), Aarhus Municipal Hospital, Herning Central Hospital, Hvidovre Hospital, Odense University Hospital, Slagelse Central Hospital, Viborg Hospital, and from the Department of Virology, Statens Serum Institut.

Sentinel surveillance of influenza activity Weekly percentage of consultations, 1999/2000/2001

% 12

10

8

6

4

2

0 27 30 33 36 39 42 45 48 51 2 5 8 11 14 17 20 23 26 29 32 35 38 41 44 47 50 1 4 7 10 13 16 19 22 25 Week

1999 2000 2001

Sentinel Alert threshold Basal curve

Sentinel: Influenza consultations as % of total consultations Basal curve: Expected frequency of influenza consultations under non-epidemic conditions Alert threshold: Possible incipient epidemic

(Dept. of Epidemiology)