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The use of mail reminders in STD contact tracing in Ibadan, Nigeria.

Contact tracing has become the most important tool in the control of sexually transmitted diseases (STDs) world-wide, and different strategies have been introduced into it in recent years to improve its effectiveness. Of all these strategy components, index patient counselling and co-operation to do their own contact tracing by themselves has been identified as the most important one. In Ibadan, it is the only component of the contact tracing strategies that has proven worthwhile. This study has assessed the contribution of supplementary mail reminders to defaulting index patients and their defaulting contacts to our control efforts in the first two years of its usage. It demonstrates that, like the other components of the contact tracing strategies, it is not successful in improving the contact or defaulting index patient attendance, thus only contributing to success in 7 of 141 patients. The intensification of efforts towards encouraging the index patient in contact tracing must therefore be ever more strongly emphasised as the top priority in STD control in Nigeria and similar developing countries for the success of this strategy.

Communicable Disease Control

Measuring the outcome of contact tracing. 1. A description of the patient and contact populations studied.

A standard system for health workers to record and handle information on patients and contacts was introduced to five clinics. Information on all the patients interviewed during the first quarter of 1975 was collected and analysed. An analysis of the characteristics of these patients showed variation between the clinics. However, regardless of what was being measured, there were always differences between men and women. It was found that not all infected patients were interviewed about their contacts. Unless or until contact tracing includes all infected patients, the effect of contact tracing on the control of the sexually transmitted diseases will be of limited value and difficult to assess.

Age Factors

Audit of a tuberculosis contact tracing clinic.

OBJECTIVE: To determine the efficiency of tuberculosis contact tracing in South Glamorgan 1987-9. DESIGN: Review of records of contact tracing clinic and of data from the Mycobacterium Reference Unit. The clinic's practice was compared with 1983 British Thoracic Society's recommendations. SETTING: Health authority tuberculosis control programme. MAIN OUTCOME MEASURES: Proportion of contacts screened, follow up attendance rates, number of secondary cases detected, and quality of record keeping. RESULTS: 101 index patients and 611 contacts were identified. 596 (97.5%) contacts were screened, of whom 139 should not have been. Of 356 contacts requiring a Heaf test, 237 were tested, seven refused the test, and 112 had chest radiography without a Heaf test. 95 contacts were unnecessarily tested. 87 contacts had chest radiography unnecessarily and seven should have had radiography but did not. 34 contacts were given follow up appointments inappropriately and seven were overlooked for follow up. Tuberculosis was diagnosed in five asymptomatic contacts, all at initial screening and all close contacts of index patients with pulmonary disease. CONCLUSION: Inadequacy of data, non-adherence to contact tracing guidelines, and failure to define the term highly infectious index case resulted in many contacts being unnecessarily screened or followed up. IMPLICATIONS: The efficiency of tracing contacts would be improved by specifying smear results and ethnic origin of the index case on the notification form, clearly classifying contacts as close or causal, and clearly defining the term highly infectious.

Adult

Contact tracing for human immunodeficiency virus (HIV) infection.

Contact tracing--or partner notification--is a generally accepted method for the control of sexually transmitted diseases (STDs), but its use as an epidemiological tool against the spread of acquired immunodeficiency syndrome (AIDS) has been questioned. The authors find contact tracing for infection with human immunodeficiency virus (HIV) quite feasible; it makes it possible for health care providers to reach people at high risk for infection in order to offer them counseling and testing. Contact tracing must be performed by someone directly engaged in caring for the HIV infected patient, as well as in giving support and aiding the patient through possible crisis reactions. Through this approach the authors were able to identify 188 contacts to 91 index patients. Thirty-eight of the contacts were seropositive for HIV infection, and 21 of these were previously unaware of their infection.

Acquired Immunodeficiency Syndrome

Contact tracing for hepatitis C: perspectives of people with experience of substance use and hepatitis C on intervention acceptability.

INTRODUCTION: Chronic hepatitis C (HCV) is a major cause of cirrhosis and hepatocellular carcinoma. In the UK, the principal risk factor for HCV is injecting drug use. The introduction of direct acting anti-virals (DAA's) have transformed HCV care, with cure rates of over 95%. However, HCV is often asymptomatic, and reinfection is a concern. Modelling and real-life studies demonstrate the potential effectiveness of a contact tracing approach for finding people who have acquired HCV through injecting drug use. However, it is not used routinely in the UK. This qualitative study was undertaken to assess the acceptability of a contact tracing approach to identify people who have injected drugs with an index patient recently diagnosed with HCV. METHODS: Twelve people with lived or living experience of injecting drug use and an HCV diagnosis were interviewed using semi-structured interview topic guides. Participants were purposefully selected according to the inclusion criteria and to ensure there was an even spread of male and female participants. Sekhon's Theoretical Framework of Acceptability, incorporating seven components (affective attitude, burden, ethicality, intervention coherence, opportunity cost, perceived effectiveness, and self-efficacy) was used to analyse data from interview transcripts. RESULTS: A sample of 12 people who inject drugs in the UK indicated that a contact tracing approach was acceptable across two components of Sekhon's acceptability framework: affective attitude and ethicality. Participants broadly found the idea of tracing people who may be at risk of contracting HCV acceptable, and the approach aligned with their value systems. A contact tracing approach would help alleviate concerns about putting other people's lives at risk through HCV transmission and was seen as a 'sensible' way of finding people at risk. However, there were caveats to this acceptability. Contact tracing approaches delivered by mainstream health, or governmental organisations increased burden, opportunity costs and perceived effectiveness of a contact tracing approach for HCV, particularly within contexts of exclusion and criminalisation of people who inject drugs. Burden and opportunity costs were also affected by individual experiences and risks of violence, sexual violence and abuse. There was a lack of knowledge of contact tracing approaches amongst respondents, leading to a lack of intervention coherence and misunderstandings of what contact tracing was and how it would work. Trusted relationships with NGOs and HCV specialist nurses reduced burden and increased confidence and ability (self-efficacy) to engage with a contact tracing approach. CONCLUSION: People who inject drugs broadly perceive contact tracing as an acceptable method of finding people who are at risk of HCV. However, this acceptability is based on specific modes of delivery through trusted organisations. Findings further highlight the importance of naming and describing contact tracing approaches appropriately, as well as assessing and mitigating against potential risk to index patients, to increase self-efficacy and capacity to engage. Considering these findings, the potential for expanding existing contact tracing approaches should be explored to ensure the UK reaches and maintains its elimination targets.

Humans

Measuring the outcome of contact tracing. 2. The responsibilities of the health worker and the outcome of contact investigations.

The previous paper (Satin and Mills, 1978) concerned information on patients who were interviewed by health workers in five selected clinics; information on the contacts named by these patients was similarly analysed. This paper describes and evaluates the activities of the health workers and the outcome of contact investigations. At all stages of the contact tracing process, differences were observed between men and women. It was found that more than half of the male contacts and half the female contacts were known to have been examined. Of those contacts examined, at least two-thirds of them attended the same clinic as the patient who had named them, and 85% of these contacts were found to have a treatable condition. It will be seen that the concept of success or effectiveness of contact tracing is complex in definition and measurement.

Allied Health Personnel

An epidemiological approach to sexually transmitted diseases--with special reference to contact tracing and screening.

Sexually Transmitted Diseases (STD) are a major health problem all over the world. The diseases are often spread by unsuspecting asymptomatic individuals. One important means of controlling STD is thus the identification of asymptomatic persons. The purposes of this thesis were a) to describe methods of identifying infected individuals through contact tracing and screening, b) to evaluate contact tracing routines, c) to compare epidemiological characteristics of two different groups of chlamydia-infected women and their partners and d) to see if data from contact tracing could be used in a model describing partner choice and STD spread. A microepidemic of penicillinase-producing gonococci was effectively controlled through contact tracing by cooperating counsellors. Serotyping of gonococci and graphic description proved of great help in mapping the contact chain. Contact tracing integrated in the psychosocial long-term care of HIV-infected patients resulted in identification of a great number of previously unidentified individuals. Screening for Chlamydia trachomatis (Ct) among asymptomatic patients of family planning clinics revealed a 7.3% Ct prevalence. Four factors were significantly correlated to the risk of being infected: age 18-23, duration of present relationship less than 1 year, failure to use condoms and no previous history of genital infection. Abstention from testing was especially high in areas with low socio-economic status. In these areas, increased resources for health care are needed. Five different levels of management of Ct infections were compared. Increased measures to verify that reported partners were examined decreased reinfections and after Ct was included in the STD Act more reported partners than before came for examination. Index patients found by chlamydia screening and their partners have a lower average number of recent partners than index patients visiting an STD clinic and their partners. Partners of female patients in the STD clinic group were also more often Ct-positive. The differences between the groups are small and do not justify different ambitions in partner management. Choice of steady partner was rather restricted and choice of casual partner followed a more random pattern. Our data thus do not support a pure random mixing model for STD spread.

Adolescent

A record system for contact tracing.

A system for recording information on patients and contacts was developed during a research project designed to measure the effectiveness of contact tracing. The record system has proved valuable in contact tracing, cross-referencing patients and their contacts, defining the characteristics of the patient and contact populations, and providing information for research and management. The value of a standardised system has been accepted by health workers who appreciate that its purpose is to increase efficiency and improve the care of infected persons. By October 1976 health workers in 16 clinics in the United Kingdom had started to use the system.

Humans

Accounting for contact tracing in epidemiological birth-death models.

Phylodynamics bridges the gap between classical epidemiology and pathogen genome sequence data by estimating epidemiological parameters from time-scaled pathogen phylogenetic trees. The models used in phylodynamics typically assume that the sampling procedure is independent between infected individuals. However, this assumption does not hold for many epidemics, in particular for such sexually transmitted infections as HIV-1, for which contact tracing schemes are included in health policies of many countries. We extended phylodynamic multi-type birth-death (MTBD) models with contact tracing (CT), and developed a simulator to generate trees under MTBD and MTBD-CT models. We proposed a non-parametric test for detecting contact tracing in pathogen phylogenetic trees. Its application to simulated data showed that it is both highly specific and sensitive. For the simplest representative of the MTBD-CT family, the BD-CT(1) model, where only the last contact can be notified, we solved the differential equations and proposed a closed form solution for the likelihood function. We implemented a maximum-likelihood program, which estimates the BD-CT(1) model parameters and their confidence intervals from phylogenetic trees. It performed accurate parameter inference on BD and BD-CT(1) simulated data, and detected contact tracing in HIV-1 B epidemics in Zurich and the UK. Importantly, we showed that not accounting for contact tracing when it is present, leads to bias in parameter estimation with the BD model (overestimation of the becoming-non-infectious rate). This bias is also present, but greatly reduced, when the BD-CT(1) model is used on data where multiple contacts can be notified. Our CT test, MTBD-CT tree simulator and BD-CT(1) parameter estimator are freely available at GitHub (evolbioinfo/treesimulator and evolbioinfo/bdct).

Contact Tracing

Audit of tuberculosis contact tracing procedures in south Gwent.

A survey of part of the work of the tuberculosis contact clinic over a 5-yr period (1984-1988 inclusive) is presented. There were 106 notified index cases and 781 contacts were screened. Following chest radiography, Mantoux tests and BCG vaccinations, only four contacts who were tuberculin-positive required chemoprophylaxis. One asymptomatic adult casual contact was treated as an active case because of shadowing on a chest radiograph. Two other cases of active tuberculosis came to light but not through the routine contact tracing procedures. All cases given treatment were contacts of a single index case and the family case history is described. Because of experience with this family the contact tracing procedures will continue locally but will be monitored prospectively. In view of different findings in other centres it is suggested a further national survey is indicated with special attention to regional variations.

Adult

Contact tracing in the control of genital Chlamydia trachomatis infection.

Four different types of contact tracing for partners of Chlamydia trachomatis infected patients were compared with respect to reinfections during two 15-month periods in 1979/80 and in 1983/84. Between the two study periods a gradual improvement in contact tracing occurred. No reduction in overall reinfections was observed in the second period, reinfections occurring within 12 weeks were similar in the two periods. Treatment of the regular partner (by giving the woman a prescription for her partner) without examination or further partner follow-up resulted in few reinfections. A system of partner referral without verification that partners actually appeared for examination resulted in significantly more reinfections by the regular partner than a system with non-mandatory verification: 60 of 997 women (6%) compared with 6 of 645 (1%). The addition of C. trachomatis infection to the existing STD legislation resulted in fewer identified partners refusing examination than previously, one of 254 men (0.4%) compared with 40 of 223 (18%) before legal inclusion.

Adult

Attitudes toward mandatory human immunodeficiency virus testing and contact tracing. A survey of intravenous drug users in treatment.

Legal initiatives and treatment policies regarding mandatory human immunodeficiency virus testing and contact tracing often are considered without the input of those groups most affected by the proposed legislation. A survey of attitudes toward the testing and tracing issues was conducted on one such group--intravenous drug users in treatment. Interview and self-report questionnaire data were collected on 196 methadone-maintained patients from two Philadelphia clinics. Data indicate that although most methadone patients supported mandatory testing, their support appears to be influenced by past testing experience. That is, significantly more untested than tested individuals were opposed to the policy. Regarding contact tracing, data indicate that most patients with seronegative results supported tracing, but of the three patients with seropositive results who were surveyed, two were opposed to it. However, most seropositive and seronegative patients reported a willingness to comply with tracing if it were to become law.

AIDS Serodiagnosis

Tuberculosis contact tracing: are the British Thoracic Society guidelines still appropriate?

The value of contact tracing in South Glamorgan for the period May 1987 to December 1989 was assessed. Tuberculosis was diagnosed in six (3.5%) of 170 close contacts. All were young and were detected in the initial screening. Tuberculosis was not found among 441 casual contacts. The value of follow up of contacts after the initial screening and of screening casual contacts in districts with a low prevalence of tuberculosis is questioned.

Contact Tracing

Contact-tracing among injection drug users in a rural area.

An epidemic of hepatitis B occurring in 1988 and 1989 in Cape Breton brought to light the existence of a group of "buddies" who engaged in injection drug use. Interviewing was conducted by Public Health in 82% of the 186 IDU contacts named. In comparison with published reports of contact-tracing efforts for viral hepatitis among IDUs, the Cape Breton experience seems successful. This article describes the approach used by Public Health. Aspects of the management of the epidemic and the interview technique which may have contributed to the comparative success of contact-tracing include collaboration with family physicians and laboratories; collaboration among public health investigators; and a nonjudgemental interview technique with 6 "golden rules".

Adult