What do we know about the outcomes of tuberculosis contact investigations in NSW?

Epidemiology of Mycobacterium bovis and Mycobacterium tuberculosis in animals: Transmission dynamics and control challenges of zoonotic TB in Ethiopia

Mycobacterium tuberculosis complex is the cause of tuberculosis (TB) in humans and other animals. Specifically, Mycobacterium bovis (M. bovis) and Mycobacterium tuberculosis (M. tuberculosis) are highly pathogenic mycobacteria that may infect different animal species and are the sources of TB in humans. The objective of this paper was to review the epidemiology of M. bovis and M. tuberculosis in animals. The review also highlighted the transmission dynamics of M. bovis and M. tuberculosis in humans and animals and control challenges of zoonotic TB in Ethiopia. The literature review focused on scientific peer-reviewed articles from studies exclusively conducted in Ethiopia that were published from 1998 to 2017. Husbandry system, breed and herd size have significant role in the epidemiology of bovine tuberculosis (BTB) in Ethiopia. The information presented reveals that different strains of M. bovis are widely distributed in domestic animals predominantly in the Ethiopian cattle and the main strain was found to be SB1176. In addition, the isolation of M. tuberculosis from domestic animals in different settings signifies the circulation of the agent between humans and animals in Ethiopia. The life styles of the Ethiopian communities, close contact with domestic animals and/or the habit of consuming raw animal products, are suggested as the main factors for transmission of M. bovis and M. tuberculosis between human and animal which may have impact on the TB control program in human. In Ethiopia, a human TB control program has been widely implemented, however, the role of animal in the transmission of the causative agent has been neglected which could be one of the challenges for an effective control program. This warrants the need for incorporating animal TB control programs using "One Health" approach for effective TB control for both human and animal.

Physicians' perspectives on communication and decision making in clinical encounters for treatment of latent tuberculosis infection

The aim of the study was to explore the views of tuberculosis (TB) physicians on treatment of latent TB infection (LTBI), focusing on decision making and communication in clinical practice.

20 Australian TB physicians participated in a semistructured interview in person or over the telephone. Interviews were recorded, transcribed and analysed thematically.

The study identified challenges that physicians face when discussing treatment for LTBI with patients. These included difficulties explaining the concept of latency (in particular to patients from culturally and linguistically diverse backgrounds) and providing guidance to patients while still framing treatment decisions as a choice. Tailored estimates of the risk of developing TB and the risk of developing an adverse effect from LTBI treatment were considered the most important information for decision making and discussion with patients. Physicians acknowledged that there is a significant amount of unwarranted treatment variation, which they attributed to the lack of evidence about the risk–benefit balance of LTBI treatment in certain scenarios and guidelines that refer to the need for case-by-case decision making in many instances.

In order to successfully implement LTBI treatment at a clinical level, consideration should be given to research on how to best address communication challenges arising in clinical encounters.

Overcoming challenges in clinical encounters is essential for implementation of treatment of latent TB infectionhttp://ow.ly/HEFu30izBUu

Attitudes towards preventive tuberculosis treatment among hospital staff

Background. Healthcare workers have an increased risk of latent tuberculosis infection (LTBI), but previous studies suggested that they might be reluctant to accept preventive tuberculosis (TB) treatment. We aimed to examine doctors’ and nurses’ experience of TB screening and to explore their attitudes towards preventive TB treatment.

Methods. We conducted a survey among randomly selected healthcare workers at a tertiary hospital in Sydney, Australia, using a paper-based questionnaire.

Results. A total of 1,304 questionnaires were distributed and 311 (24%) responses were received. The majority of hospital staff supported preventive TB treatment in health care workers with evidence of latent TB infection (LTBI) in general (74%, 164/223) and for them personally (81%, 198/244) while 80 and 53 healthcare workers respectively had no opinion on the topic. Staff working in respiratory medicine were significantly less likely to support preventive TB treatment in health care workers in general or for them personally if they would have evidence of LTBI compared to other specialties (p = 0.001). Only 13% (14/106) of respondents with evidence of LTBI indicated that they had been offered preventive TB treatment. Twenty-one percent (64/306) of respondents indicated that they did not know the difference between active and latent TB. Among staff who had undergone testing for LTBI, only 33% (75/230) felt adequately informed about the meaning of their test results.

Discussion. Hospital staff in general had positive attitudes towards preventive TB treatment, but actual treatment rates were low and perceived knowledge about LTBI was insufficient among a significant proportion of staff. The gap between high support for preventive TB treatment among staff and low treatment rates needs to be addressed. Better education on the concept of LTBI and the meaning of screening test results is required.

Evaluation of tuberculin skin testing in tuberculosis contacts in Victoria, Australia, 2005-2013

AIM

To review the programmatic use of the tuberculin skin test (TST) following tuberculosis (TB) exposure in Victoria, Australia.

METHODS

A retrospective review of data collected for public health surveillance was performed to identify contact demographic factors, including bacille Calmette-Guérin (BCG) status and age and outcomes of TST.

RESULTS

Contact tracing was performed for 15 094 people, of whom 13 427 (89.0%) had a TST performed. The TST was positive in 31.4% (95%CI 30.6-32.2) of all contacts, and 48.8% of contacts born outside of Australia. Amongst contacts who were TST-negative at baseline, the conversion rate following exposure was 14.8%. Conversion was most common in those aged 45-54 years, with <12% positivity in both the youngest (<5 years) and oldest (⩾65 years) age groups. Active TB developed in 1.1% of all contacts. Contacts aged <5 years had the highest risk of developing active TB following exposure (3.8%), while low risk was seen in those aged ⩾65 years (0.3%).

CONCLUSION

Overall, contact tracing and TST in this setting appear to yield a high proportion of people at risk for the development of active TB. The yield of testing in some groups, particularly those aged ⩾65 years, was low, and investigation of alternative strategies should be considered.

What patient factors predict physicians' decision not to treat latent tuberculosis infection in tuberculosis contacts?

Objective

The study aimed to determine factors that are associated with physicians’ decision to offer treatment for latent tuberculosis infection (LTBI) in contacts of patients with tuberculosis.

Methods

We performed a nested case-control study in a cohort of contacts of patients with pulmonary tuberculosis who had a tuberculin skin test (TST) ≥ 10 mm. Cases were those who were offered treatment for LTBI. Controls were randomly selected from those who were not offered treatment for LTBI by the reviewing physician. Odds ratios were estimated by multivariate logistic regression.

Results

There were 195 cases and 279 controls. The following factors were significantly (positively or negatively) associated with being offered LTBI treatment in the multivariate analysis: female gender (OR 2.9; 95% CI 1.6–5.5), TST conversion (OR 3.9; 2.0–7.9), TST > 20 mm (OR 4.1; 1.8–9.1, for TST of 21–30 mm and OR 7.9; 2.6–23.8, for TST >30 mm), sputum smear positive index case (OR 12.7; 4.5–36.1), being overseas-born and immigration more than 2 years ago (OR 0.1; 0.06–0.3), being a health care worker (OR 0.2; 0.1–0.6), being a non-household contact of the TB index case (OR 0.3; 0.2–0.6) and age >35 years (OR 0.2; 0.1–0.5 for age 35 to 54.9 years and OR 0.04; 0.01–0.2 for age ≥55 years). Previous BCG vaccine and chest x-ray findings were not significantly associated with physicians’ decision to offer treatment for LTBI.

Conclusions

Most factors that influenced physicians’ decisions on treatment for LTBI were based on evidence of an association with risk of developing TB or risk of having an adverse reaction to treatment for LTBI. However, the decreased likelihood of offering treatment for LTBI to people born overseas, men and health care workers, was apparently not based on any evidence of risk. Efforts should be made to ensure that these groups are given access to treatment for LTBI.