Evaluation and follow-up of infectious tuberculosis at the University of Ottawa

Ottawa-Carleton Health Department, Communicable Disease Program, Ottawa, Ontario Correspondence and reprints: Dr Ziad A Memish, Consultant Infectious Diseases, King Fahad Hospital, Department of Infectious Diseases, PO Box 22490 Riyadh 11426, Saudi Arabia. Telephone 9661 252 0088, fax 9661 252 0140 Received for publication August 1, 1994. Accepted Feburary 21, 1995 ZA MEM ISH, R HICKEY, I GEM MILL. Evalua tion and followup of in fec tious tu ber cu lo sis at the Uni ver sity of Ot tawa. Can J In fect Dis 1995;6(5):239243. A case of ac tive in fec tious pul mo nary tu ber cu lo sis (TB) in a re cent im mi grant to Can ada was iden ti fied at the Uni ver sity of Ot tawa. The stu dent was at tend ing classes regu larly and cough ing for six months be fore the di ag no sis of in fec tious pul mo nary TB was made. In ves ti ga tion car ried out by the OttawaCarleton Health De part ment iden ti fied 871 stu dent con tacts. Of the 871 con tacts, 773 (89%) were avail able for test ing and followup. Ini tial skin test ing with pu ri fied pro tein de riva tive (PPD) was posi tive in 149 con tacts. Of the 602 con tacts test ing nega tive ini tially 399 (66%) re turned for 12week re test ing. Eleven skin test con vert ers were iden ti fied. All 160 con tacts with posi tive PPD had nega tive chest xray and were given isonia zid pro phy laxis for six months. The es ti mated cost of the pro cess of con tact trac ing, test ing, followup and treat ment was $34,036. Al though preimmigration screen ing poli cies for TB do ex ist, ad di tional preand postim mi gra tion meas ures could help in the early de tec tion of ac tive TB and the pre ven tion of its spread.

I N THE EARLY 1980s, THE CEN TERS FOR DIS EASE CON TROL (AT - lanta, Geor gia) set a goal for tu ber cu lo sis (TB) eradi ca tion by the year 2010 (1).In the last dec ade of the 20th cen tury, eradi ca tion of TB seems less likely and ef forts are aimed at con trol ling its spread.In the United States, the number of new TB cases de clined un til 1984; the in ci dence in 1985 was sta ble but a 16% in crease oc curred in 1986.Since then, a con tinuous in crease in TB in ci dence has been noted.This oc cur rence was at trib ut able in part to the co-infection of some popu la tions with hu man im mu no de fi ciency vi rus and My co bac te rium tuber cu lo sis (2)(3)(4).
In Can ada the number of new TB cases has con tin ued to de cline since 1984, with only a slight in crease noted in 1989 (2.4%), 1991, 1992 and 1993 (5).This in crease was re lated to the in flux of im mi grants to Can ada from third-world coun tries where TB is en demic and tools for pre ven tion, treat ment and con trol of TB may be lack ing.
Through im mi gra tion, in di vidu als in fected with TB in their child hood bring with them this geo graphi cal risk fac tor for disease; with the stress of im mi gra tion and per sonal and so cial dis rup tion, re ac ti va tion is com mon, es pe cially within five years of im mi gra tion (7)(8)(9)(10)(11).Over all, the great est in crease in cases of TB in Can ada be tween 1980 and 1990 oc curred in im mi grants, with sub stan tial de cline in the in ci dence in the non-Native popu la tion born in Can ada.
The pres ence of one case of in fec tious TB may carry the risk of ex pos ing hun dreds of healthy in di vidu als to the disease.The follow-up and treat ment of con tacts is time consum ing, ex pen sive and very wor ri some to peo ple ex posed to TB with out their knowl edge.This situa tion raises the ques tion of whether pre-immigration medi cal poli cies and pro ce dures pro vide ade quate screen ing and care to new ar ri vals and protec tion to the un in fected in the Ca na dian popu la tion.We review a case of in fec tious TB in an im mi grant to Can ada, whose in fec tion was not de tected by im mi gra tion screen ing, and who had more than 800 con tacts who re quired test ing and followup.

CASE PRES EN TA TION
The in dex case was a sin gle, 27-year-old fe male who immi grated to Can ada from Viet nam on Janu ary 1,1990.She came from a mid dle class fam ily and re mem bered al ways being healthy.There was no sig nifi cant past medi cal his tory.
The pa tient re mem bered hav ing Ba cille Calmette-Guérin (BCG) vac cine as a child as did all her fam ily mem bers.As part of the pre-immigration medi cal ex am i na tion she and her fam ily mem bers had chest x-rays re ported as nor mal.No TB skin test was done ei ther be fore or af ter en ter ing Can ada, un til late in her ill ness.
She came with her par ents and three sib lings to live with her eld est brother who had been in Can ada for 13 years.In August 1992 she en tered the Uni ver sity of Ot tawa as a fulltime stu dent.In Sep tem ber 1992, she started to feel un well with con tinu ous dry cough; there were no as so ci ated shortness of breath, fe ver or chills.Chest x-ray done at the end of Sep tem ber re vealed right lower lobe in fil trate.This con di tion was treated with four courses of dif fer ent an ti bi ot ics over three to four months with mini mal im prove ment.
On Feb ru ary 25, 1993 she was re as sessed for per sis tent clini cal symp toms and chest x-ray ab nor mali ties.A skin test with five pu ri fied pro tein de riva tive (PPD) test units was done and was posi tive at 22 mm.Spu tum showed nu mer ous acidfast ba cilli and TB cul tures were ini ti ated.The pa tient was assessed by a res pi rolo gist for treat ment on March 5. Quad ru ple ther apy with isoni a zid, ri fampin, pyrazi na mide and eth am butol was started.Three sub se quent spu tum sam ples were nega tive for acid-fast ba cilli.The fi nal cul ture re port of spu tum was posi tive for M tu ber cu lo sis, sen si tive to all anti-TB drugs.
The in dex case had at tended classes regu larly since the be gin ning of the school year.She was not able to iden tify regu lar con tacts at school and stated that she sat at dif fer ent places at dif fer ent times in her classes.The audi to ria hold about 125 stu dents and the class rooms hold about 50 students each.There is cen tral ven ti la tion but no win dows in these rooms.The air cir cu lates back to other classes with a par tial fresh air ex change.
She also took lo cal buses to and from the uni ver sity.The to tal trav el ling time was 45 mins with no trans fers.Dur ing the win ter, all bus win dows were kept closed.

HEALTH DE PART MENT IN TER VEN TION
The Health De part ment was no ti fied im me di ately of positive spu tum smears by the res pi rolo gist.The fol low ing in terven tions were im ple mented: • The patient was excluded from the university and confined to home for three weeks after initiation of quadruple therapy with a public health nurse visit twice weekly to ensure compliance with treatment and to educate the patient about the disease.
• Screening of family contacts revealed that of four household contacts, only one sister had positive PPD (11 mm) but negative chest x-ray.She was treated with isoniazid for six months.
• The University Health Services medical director was contacted and informed of the situation, and arrangements were made for a skin testing clinic to be held on campus for all 871 contacts.Health Department staff ran the clinic with assistance from the University Health Services.
• A letter was written to the Dean of the Department in which the patient was registered to request formally the list of names, dates of birth, temporary and permanent addresses and telephone numbers of contact students sharing the same classes.
• A letter was formulated by the University and distributed to every student in any class with the index case.This letter gave information on why the test was needed and when it would take place.
• To ensure compliance with testing, the University decided that students would not receive their examination results until they had provided proof of follow-up to their TB exposure.
• Two-step PPD testing was done only for those who were over 35 years of age; who had previous history of BCG vaccine or previously had positive Mantoux tests PPD; or who had spent more than three months in an endemic area.
• Contacts who did not attend the clinics were sent a letter by the University telling them to make arrangements with their doctor for testing and forwarding of results to the Health Department.
• All contacts who were negative on the first test were given a letter with the date of final testing 12 weeks later, and instructions for the physician to send the result to the Health Department.
• All contacts with a positive Mantoux test were referred to University Health Services or their own doctor with a copy of the Health Department recommendations for assessment and isoniazid prophylaxis.A request was made to inform the Health Department of the course of action taken.
• Contacts with positive Mantoux test were contacted by public health nurses at least every three months to ensure compliance with isoniazid prophylaxis and medical follow-up.
• Contacts who had left the region were referred to the appropriate health unit for follow-up.

RE SULTS
The to tal number of con tacts iden ti fied through the sur veillance was 871 (Fig ure 1).This number in cluded all stu dents who at tended classes with the in dex case in the same room for more than 45 mins on mul ti ple oc ca sions.Be cause it was im pos si ble to de ter mine ac cu rately who was most closely exposed to the in dex case over the six-month pe riod, all students were in cluded ac cord ing to the cri te ria noted.Of the to tal 871 con tacts, 773 (89%) com plied with test ing and follow-up.Ninety-eight con tacts had no test ing.Nine peo ple who had had a posi tive Man toux test within the pre vi ous five years or who had had a pre vi ous se vere re ac tion to test ing had chest x-rays.All of these chest x-rays were nega tive.
The re sults of the first PPD test ing showed 149 posi tives out of 764 tested (19.5%).Two-step test ing was done for 144 con tacts meet ing the cri te ria.Of those, 13 had posi tive re actions.
Re test ing af ter 12 weeks was done in 399 con tacts; 11 con ver sions (2.8% of those re tested) were docu mented.This fig ure is the best in di ca tion of trans mis sion.Two hun dred and three stu dents did not have fi nal test ing de spite the Uni ver sity pol icy.
The es ti mated to tal cost of the pro cess of con tact trac ing, test ing, follow-up and treat ment was $34,036.Ta ble 1 summa rizes the ex penses.

DIS CUS SION
This in ter ven tion was com plex, time con sum ing and expen sive.De spite all ef forts 98 (11%) con tacts were not tested, All the 162 con tacts who had a posi tive Man toux test initially had nor mal chest x-rays and it could not be de ter mined with cer tainty whether the posi tive skin tests were re lated to the in dex case or to pre vi ous ex po sure in an en demic coun try.All these stu dents were given isonia zid pro phy laxis as rec ommended by the Ca na dian Lung As so cia tion and Ameri can Tho racic So ci ety (12).
The 11 skin con vert ers at 12 weeks are proba bly re lated to the in dex case.All of them had a nega tive chest x-ray and were given isonia zid pro phy laxis.Since there were 203 students who did not re turn for the 12-week re test ing, it can not be de ter mined how many ad di tional stu dents con verted and whether any sec on dary case may have re sulted from this in cident.
This case calls into ques tion cur rent im mi gra tion medi cal re quire ments.The im mi gra tion ex ami na tion in cludes tak ing a his tory; physi cal ex ami na tion; chest x-ray if the ap pli cant is older than 11 years; uri naly sis if the ap pli cant is older than five years; and se ro logi cal test ing for syphi lis if the ap pli cant is older than 15 years (13)(14)(15).The history-taking and physi cal ex ami na tion are done by a lo cal phy si cian in the coun try of ori gin ap pointed by the De part ment of Citi zen ship and Im migra tion.The ac cu racy and qual ity of this as sess ment var ies and the labo ra tory test ing may be mis in ter preted or mis rep resented; both poor qual ity chest x-ray and fraudu lently rep resented chest x-ray oc cur.These tests are done out side Can ada and the medi cal find ings are re viewed by a Ca na dian medi cal of fi cer.TB, es pe cially in peo ple com ing from en demic ar eas, may be in cu bat ing or dor mant and may not be detected by these screen ing meth ods.
The tu ber cu lin skin test is not in cluded in the Ca na dian rec om men da tion for im mi gra tion TB screen ing, al though it is a pre dic tor for the de vel op ment of TB over time.Those with inac tive TB are ad mit ted with no ti fi ca tion to pro vin cial TB con trol.Lo cal health units may re ceive these re ports months af ter im -mi gra tion, of ten too late to find the in di vid ual or af ter TB has already re ac ti vated.Ap pli cants are de ferred un til sat is fac tory treat ment has been ad min is tered for in fec tious TB or syphi lis.No at tempt is made to as sess on go ing risk for TB by skin testing.This pro ce dure is felt to be too dif fi cult for ap pli cants and to iden tify too many posi tives.
We there fore of fer the fol low ing rec om men da tions for immi gra tion medi cal screen ing.First, TB skin test ing on ar ri val by Ca na dian medi cal of fi cers to as sess risk for fu ture TB in both im mi grants and refu gees; sec ond, re fer ral of posi tives ex pe di tiously to lo cal health units, with a re quire ment for the refu gee or im mi grant to fol low up with their health unit; and finally, a re view of cur rent in fec tious dis ease screen ing to provide im mi gra tion screen ing based on in ci dence and the prac ti cal ity of in ter ven tion.In fec tions such as hepa ti tis B and oth ers should be con sid ered for in clu sion.The health of the in di vid ual and the pro tec tion of Ca na di ans should both be given pri or ity.
As TB makes a re sur gence in com mu ni ties set tled by people with geo graphi cal risk fac tors for this dis ease, pri mar ily the larg est ur ban cen tres in Can ada, bet ter screen ing for this and other dis eases is re quired.With new pat terns of im mi gration, a pre dict able number of new in fec tious TB cases will occur, some times in a large risk set ting such as high school or uni ver sity.More com pre hen sive screen ing and follow-up will bene fit the af fected in di vidu als through ear lier in ter ven tion and less rea son for back lash against popu la tions at risk for TB; it will bene fit the Ca na dian pub lic through re duced risk of ex po sure to in fec tious dis ease; and it will bene fit in sti tu tions in which cases oc cur through less dis rup tion.A full re view of the in fec tious dis ease com po nent of the im mi gra tion medi cal exami na tion is re quired to bene fit all these groups and to sat isfy the re quire ments of the Im mi gra tion Act.CAN Re sults of tu ber cu lo sis follow-up at the Uni ver sity of Ot tawa.PPD Pu ri fied pro tein de riva tive CAN J INFECT DIS VOL 6 NO 5 SEP TEM BER/OCTO BER 1995 and 203 (23%) of the con tacts re quir ing Man toux re test ing at 12 weeks did not re turn.

TA BLE 1 Uni ver sity of Ot tawa clinic costs Item Amount ($) To tal cost ($) (ac tual or es ti mated)
J INFECT DIS VOL 6 NO 5 SEP TEM BER/OCTO BER 1995Uni ver sity of Ot tawa print ing costs, the time for pub lic health nurse home vis its and tele phone calls are not ac counted for in these fig ures