Tuberculosis: an Ongoing Challenge?

TUBERCULOSIS: AN ONGOING CHALLENGE?

Outbreak Control Team: T. FitzGerald, P. Lanigan, A. Veale, M. Hickey, K. Molloy, P. Prendiville, N. DeSouza, M. O’Connor, O. O’Reilly

Public Health Department, South Eastern Health Board, Lacken, Kilkenny, Ireland.

1. Introduction

During 2000/2001, a Community Care Area serving a population of 100,000 notified a total of 21 new cases of pulmonary Tuberculosis (TB) to the Department of Public Health.

Of these 21 cases, 8 patients (38%) lived in a city suburb. This suburb of 763 publicly provided houses (population 3000) is an area of high unemployment, high levels of substance abuse and homelessness, dysfunctional interpersonal relationships and high dependency on welfare services.

An Outbreak Control Team (OCT) was formed specifically to investigate possible links between the 8 cases, and to implement prevention and control measures in accordance with national and local guidelines.

1. Outbreak Control Team Response

The OCT was comprised of:

- Medical Specialists in Public Health

- Community Medical Officers

- Public Health Nurses

- Consultant Microbiologist

In addition to standard contact tracing procedures, the OCT:

- Raised local awareness by media, public fora and local poster displays

- Alerted local medical practitioners

- Selected personnel known to and by the local community

- Made home visits (112) to known contacts and contacts identified by 3rd parties

- Held walk-in outreach clinics (including out-of-hours) for two weeks in nearby Health Centres (18 clinics in addition to routine weekly clinic at the local hospital)

- Arranged specific x-ray sessions

- Provided free transport to x-ray department

- Arranged supervised collection of sputum specimens, where necessary

- Increased the provision of directly observed treatment (DOT)

- Sought legal advice on compulsory hospitalisation for non-compliance with treatment and the use of alias names on hospital records

- Requested DNA fingerprinting by Restriction Fragment Length Polymorphism (RFLP) of M tuberculosis in the 8 cases

1. Outcome of initial screening exercise

(a) DNA fingerprinting (RFPL) of initial 8 cases

(b) Contact tracing of initial 8 cases

* Preventive therapy with Isoniazid was commenced in contacts less than 30 years of age with positive Mantoux test and normal chest x-ray.

(c) Difficulties encountered during initial contact tracing

Reluctance of cases to identify contacts due to:

- Temporary house residents affecting tenancy/rent/welfare allowances

- Unacknowledged past and present relationships

- Mistrust of statutory agencies

- Unreliable/false information, including names, given by contacts

- Frequent change of address (within the estate)

- Reluctance of contacts to attend screening clinic

- Non-compliance with treatment/ preventive therapy

4.Outcome of intensive contact tracing

During the six-week period of intensive contact tracing, screening identified six new cases of TB including four patrons of a local public house (pub/bar). Nine contacts commenced preventive therapy.

Simultaneously, three cases living in the area, presented through their medical practitioner.

5.Summary

In a two-year period (2000/2001), 8 cases of TB occurred in a city suburb. DNA RFLP fingerprinting identified 5 cases belonged to a single cluster, 2 cases in a second cluster and 1 in a third. Intensive contact tracing, specially adapted by the OCT to the characteristics of the area, was commenced. 1 case, presenting through a medical practitioner, extended the screening process to a local public house.

By the end of 2002, 12 of 27 (44%) cases notified to the Department of Public Health, lived in the identified suburb. Of these 12 cases, 6 were found by screening and 6 presented through their medical practitioner. DNA (RFLP) testing confirmed 10 cases in Cluster 1. 2 results are awaited. In addition, a taxi driver, not living in the suburb was identified in Cluster 1.

In 2003, of 9 notified cases, 4 (44%) live in the suburb. 1 was a high-risk contact under supervision, and 3 presented as patients. A further 2 cases (22%) have possible links to the area (DNA results awaited).

To date, no new cases have been identified in Cluster 2or 3.

Cases resident in identified suburb 2000-2003

*DNA results are awaited in 6 cases from the area and in 2 possible linked cases.

6 cases and 2 contacts received directly observed treatment.

Legal advice sought on compulsory hospitalisation of patients who were non-compliant with treatment and on the implications of a patient using an alias in hospital records was unhelpful.

1. Conclusions

In this study, a large minority (42%) of patients notified to the Department of Public Health during 2000-2002 were residents of a single, socially deprived, city suburb.

DNA typing was helpful in ascribing individual cases to the outbreak. Initially, social and attitudinal problems of the community and of individual cases hindered identification of contacts. Control and prevention measures, specifically tailored to the characteristics of the local community, were essential to increasing the uptake of screening and slowing the rate of transmission of infection. A news and information item in a newspaper, delivered free to all households in the city, was employed to raise the level of awareness of TB in the general population. Alerting local medical practitioners to the outbreak was aimed at raising the index of suspicion of TB in diagnosis. The amount of third party information was surprising and greatly boosted the contact tracing effort. However, despite the short-term intensive contact tracing exercise, cases are still being notified from this suburb. In 2003, of 9 cases notified, 6 (66%) have possible links to Cluster 1.

In retrospect, it is likely that the outbreak originated in a family group within the estate and was spread by a homeless case to a patron of the public house where a secondary outbreak occurred. The need for members of the outbreak team to concentrate on the investigation led to their redeployment from other public health activities, to the detriment of these services.

1. Recommendations

Routine DNA should be considered when two or more seemingly unrelated cases of TB occur in a small geographic area.

Increased focus should be placed on obtaining 3rd party information when contacts are reluctant to divulge critical facts.

Select personnel known to and by the local community to contact trace in an area where mistrust of statutory agencies is evident.

In an outbreak, adequate resources should be available to allow for extended periods of intensive contact tracing.