What is the impact of change in diagnostic test method on surveillance data trends in Chlamydia trachomatis infection?

Australia's notifiable disease status, 2016: Annual report of the National Notifiable Diseases Surveillance System

Abstract

In 2016, a total of 67 diseases and conditions were nationally notifiable in Australia. The states and territories reported 330,387 notifications of communicable diseases to the National Notifiable Diseases Surveillance System. Notifications have remained stable between 2015 and 2016. In 2016, the most frequently notified diseases were vaccine preventable diseases (139,687 notifications, 42% of total notifications); sexually transmissible infections (112,714 notifications, 34% of total notifications); and gastrointestinal diseases (49,885 notifications, 15% of total notifications). Additionally, there were 18,595 notifications of bloodborne diseases; 6,760 notifications of vectorborne diseases; 2,020 notifications of other bacterial infections; 725 notifications of zoonoses and one notification of a quarantinable disease.

Australia’s notifiable disease status, 2015: Annual report of the National Notifiable Diseases Surveillance System

In 2015, 67 diseases and conditions were nationally notifiable in Australia. States and territories reported a total of 320,480 notifications of communicable diseases to the National Notifiable Diseases Surveillance System, an increase of 16% on the number of notifications in 2014. In 2015, the most frequently notified diseases were vaccine preventable diseases (147,569 notifications, 46% of total notifications), sexually transmissible infections (95,468 notifications, 30% of total notifications), and gastrointestinal diseases (45,326 notifications, 14% of total notifications). There were 17,337 notifications of bloodborne diseases; 12,253 notifications of vectorborne diseases; 1,815 notifications of other bacterial infections; 710 notifications of zoonoses and 2 notifications of quarantinable diseases.

Increased incidence of gonorrhoea and chlamydia in Greenland 1990-2012

Background: Since the 1970s, Greenland has presented the highest reported incidence rates of the sexually transmitted infections (STIs) gonorrhoea and chlamydia in the Arctic regions.

Objective: This study aims to describe sex- and age-specific incidence rates of gonorrhoea and chlamydia from 1990 to 2012 in Greenland, and to evaluate if changes in case definitions, diagnostic procedures and implementation of STI interventions during the period coincide with rate changes.

Design: Gonorrhoea and chlamydia cases were identified from the national STI surveillance. For 1990–2008, STI cases were identified from weekly notified aggregated data. For 2009–2012, cases were identified in person-identifiable national registers. We used log-linear Poisson regression to calculate incidence rates (IRs) and incidence rate ratios (IRRs) with 95% confidence intervals (95% CI). Analyses were stratified according to sex, age and calendar period.

Results: Gonorrhoea and chlamydia incidence rates have increased since 1995 to reach 2,555 per 100,000 person-years (PY) for gonorrhoea and 6,403 per 100,000 PY for chlamydia in 2012. From 2006 to 2012, the incidence rates among young adults aged 15–19 years were 8,187 and 22,515 per 100,000 PY for gonorrhoea and chlamydia, respectively. Changes in surveillance reporting did not seem to influence the incidence rates for either disease, whereas a change in diagnostic test coincided with an increased incidence of chlamydia.

Conclusion: Overall, the incidence of chlamydia in Greenland increased during the study period, whereas the incidence of gonorrhoea decreased until 1995 but increased thereafter. Young adults aged 15–24 years were at highest risk of infection. The increase in incidence rates was independent of changes in case definitions, whereas an observed increase in chlamydia incidence in 2005 coincided with a change in diagnostic test. None of the STI interventions launched after 1995 seemed to coincide with decreasing national incidence rates.

Striking ethnic variations in the epidemiology of Chlamydia trachomatis in Haifa District, Israel, throughout the years 2001-2015

Our objectives were to examine trends in the incidence of chlamydia over an extended period and compare the epidemiology of the infection between two distinct ethnic groups in Israel: Jews and Arabs. We examined the incidence rate of Chlamydia trachomatis infection among residents of Haifa District, northern Israel from 2001 to 2015, by reviewing archives of the Department of Epidemiology, Ministry of Health. Notified cases were stratified by age group, gender, and ethnic group. The overall incidence rate of Chlamydia was 10.8 cases per 100,000 population per year. The annual rate increased dramatically from 5.1 per 100,000 population in 2001, to an all-time high of 18.5 cases per 100,000 population in 2015 (P < 0.001), representing an increase of 362.7%. The most affected age group was 25-34 years of age. The estimated rate among Jewish inhabitants was ninefold higher than among Arabs. Only 3% recurrent episodes of Chlamydia were registered. The prevalence of HIV positivity among Chlamydia-infected patients was similar to that of the general population. In conclusion, Chlamydia in Haifa has been continuously increasing since 2001 and the infection is much more prevalent among patients of Jewish ethnicity, mainly due to more hazardous sexual practices in this population.

Interpretation of laboratory detection trends for Chlamydia trachomatis and Neisseria gonorrhoeae: Manitoba, Canada, 2000-2012

OBJECTIVES

Increases in case numbers for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) have been noted on a global level. This study analysed 13 years of testing data to better understand case detection trends over time.

METHODS

Data consisted of all nucleic acid probe and nucleic acid amplification diagnostic testing for CT and NG for the population of Manitoba, Canada (1.2 million); January 2000 to December 2012. Logistic regression models were used to analyse ORs associated with positive CT and NG tests by year. Included in the model as predictor variables were test type, specimen type, patient age and residence location.

RESULTS

For both male and female CT results, unadjusted OR by year mimicked absolute case counts, reflecting a general increase over time in case counts. Adjustment for laboratory-related variables altered this relationship such that a general decline in the odds of identifying a CT case over time was evident. For both male and female NG results, adjustment for laboratory and demographic variables altered the OR associated with each year, but to a lesser extent than for CT.

CONCLUSIONS

Temporal trends associated with CT case numbers should be interpreted after controlling, at a minimum, for the influence of laboratory-related variables. Interpretation of NG trends is feasible using only the number of reported NG cases.

How do changes in the population tested for chlamydia over time affect observed trends in chlamydia positivity? Analysis of routinely collected data from young women tested for chlamydia in family planning clinics in the Pacific Northwest (USA), between 2003 and 2010

Background The proportion of chlamydia tests that are positive (positivity) is dependent on the population tested and the test technology used. The way in which changes in these variables might affect trends in positivity over time is investigated.

METHODS

Data from 15- to 24-year-old women tested for chlamydia in family planning clinics participating in the Infertility Prevention Project in the Pacific Northwest, United States (USA Public Health Service Region X) during 2003-2010 (n=590557) were analysed. Trends in positivity and in test, demographic and sexual behaviour variables were identified. Unadjusted and adjusted trends in chlamydia positivity were calculated using logistic regression.

RESULTS

The proportion of tests carried out using nucleic acid amplification tests (NAATs) increased dramatically during the analysis period in two states. Smaller changes in demographic and behavioural characteristics were seen. Controlling for test technology used had the largest effect on the trend in testing positive per year, leading to a fall in the calculated odds ratio of testing positive from 1.06 to 1.02 in Oregon, and from 1.07 to 1.02 in Idaho. Controlling for other variables had minimal effect on chlamydia positivity trends.

CONCLUSIONS

Changes in NAAT use had a large effect on observed trends in chlamydia positivity over time in the two states where NAATs were introduced during the analysis period. While trends in chlamydia positivity may be a useful metric for monitoring chlamydia burden, it is important to consider changes in test type when interpreting these data.

Chlamydia trachomatis Infection: Screening and Management

OBJECTIVE

To review current criteria and rationale for Chlamydia trachomatis screening, testing methods, and treatment of infection.

METHODS

Review of the literature.

RESULTS

C. trachomatis urogenital infections are an important public health problem. Screening for C. trachomatis in women age 25 and younger and men and women of any age at increased risk allows for the early treatment of disease, avoiding morbidity such as pelvic inflammatory disease, ectopic pregnancy, and chronic pelvic pain, and reducing health care costs.

CONCLUSION

Current screening recommendations are not being implemented satisfactorily. Home-based methods of screening are acceptable and may improve universal screening rates.

Spolno Prenosljive Okužbe Z Bakterijo Chlamydia Trachomatis V Sloveniji / Sexually Transmitted Infections With The Bacteria Chlamydia Trachomatis In Slovenia

Namen:Namen prispevka je na osnovi sistematičnega pregleda objavljenih raziskav oceniti prevalenco genitalnihokužb z bakterijo Chlamydia trachomatis v Sloveniji.

Metode:Pregledana je bila literatura v dveh elektronskih podatkovnih zbirkah, in sicer v zbirki PubMed z uporabokombinacije ključnih besed »chlamydia« in »Slovenia« ter v zbirki Cobiss Slovenija s pomočjo ključnih besed»klamidija«, »chlamidia« in »chlamydia«. Vključene so raziskave, ki so bile v navedenih zbirkah vpisane do vključnokonca novembra 2011 in so vsebovale izsledke o pogostosti klamidijskih okužb med prebivalci Slovenije.

Rezultati:V obdobju od leta 1980 do vključno konca novembra 2011 je bilo objavljenih 18 raziskav, ki so ustrezaleiskalnim merilom. Večina raziskav je bila izvedena na različnih skupinah prebivalcev Slovenije in ne na verjetnostnihnacionalnih vzorcih. Klamidijska okužba je bila ugotovljena v 0-19% primerih. Pri preiskovancih z nekaterimi stanji,ki so lahko povezana z višjo prevalenco spolno prenosljivih okužb, je bila klamidijska okužba ugotovljena v 4,9-19%,pri tistih, ki takšnih stanj niso imeli opisanih, pa v 0-16,5%. Pet raziskav je bilo končanih po letu 2000 in pri teh jebila klamidijska okužba ugotovljena v 0-6,5%. Največ okuženih je med starimi 20 in 24 let.

Zaključki:Chlamydia trachomatis je pomembna povzročiteljica spolno prenosljivih okužb v Sloveniji. Večineklamidijskih okužb zaradi nizkih stopenj testiranja ne prepoznamo in tako zamujamo številne priložnosti za zdravljenjein preprečevanje kasnih posledic, predvsem za reproduktivno zdravje žensk

Trends in age disparities between younger and middle-age adults among reported rates of chlamydia, gonorrhea, and infectious syphilis infections in Canada: findings from 1997 to 2007

BACKGROUND

The objective was to determine trends in age disparities between reported rates of chlamydia, gonorrhea, and infectious syphilis among younger versus middle-age Canadians.

METHODS

We examined age- and sex-specific reported rates of chlamydia, gonorrhea, and infectious syphilis between 1997 and 2007. Sexually transmitted infection (STI) rates in the younger age group (15-29 years) were compared to the middle-age group (40-59 years) over the 11-year period. We used Poisson regression to examine trends in age-specific (younger:middle-age) rate ratios.

RESULTS

Between 1997 and 2007, both the number and rate of reported cases increased for all 3 nationally notifiable STIs. Although chlamydia and gonorrhea rates continued to be higher among younger adults, rates of all 3 STIs increased more dramatically among middle-age adults. Between 1997 and 2007, chlamydia rates increased by 86.8% among adults aged 15 to 29 (P <0.0001) and 165.9% among adults 40- to 59-years-old (P <0.0001). The corresponding increases for gonorrhea were 133.3% (P <0.0001) and 210.2% (P <0.0001) respectively. Infectious syphilis rates increased 5-fold among younger adults compared to an increase of 11-fold among middle-age adults (P <0.0001) since 1997. The reported rate ratios (younger:middle-age) decreased over time for chlamydia (P <0.0001), gonorrhea (P <0.0001), and syphilis (P = 0.005). Males were disproportionately represented among reported chlamydia, gonorrhea, and infectious syphilis cases, constituting 59.8%, 87.6%, and 93.0% of middle-age adult cases, respectively, in 2007.

CONCLUSIONS

Middle-age adults may be increasingly affected by chlamydia, gonorrhea and infectious syphilis. There is a need for sexual health information targeting Canada's middle-age adults and their health care providers.

Current crisis or artifact of surveillance: insights into rebound chlamydia rates from dynamic modelling

Background

After initially falling in the face of intensified control efforts, reported rates of sexually transmitted chlamydia in many developed countries are rising. Recent hypotheses for this phenomenon have broadly focused on improved case finding or an increase in the prevalence. Because of many complex interactions behind the spread of infectious diseases, dynamic models of infection transmission are an effective means to guide learning, and assess quantitative conjectures of epidemiological processes. The objective of this paper is to bring a unique and robust perspective to observed chlamydial patterns through analyzing surveillance data with mathematical models of infection transmission.

Methods

This study integrated 25-year testing volume data from the Canadian province of Saskatchewan with one susceptible-infected-treated-susceptible and three susceptible-infected-treated-removed compartmental models. Calibration of model parameters to fit observed 25-year case notification data, after being combined with testing records, placed constraints on model behaviour and allowed for an approximation of chlamydia prevalence to be estimated. Model predictions were compared to observed case notification trends, and extensive sensitivity analyses were performed to confirm the robustness of model results.

Results

Model predictions accurately mirrored historic chlamydial trends including an observed rebound in the mid 1990s. For all models examined, the results repeatedly highlighted that increased testing volumes, rather than changes in the sensitivity and specificity of testing technologies, sexual behaviour, or truncated immunological responses brought about by treatment can, explain the increase in observed chlamydia case notifications.

Conclusions

Our results highlight the significant impact testing volume can have on observed incidence rates, and that simple explanations for these observed increases appear to have been dismissed in favor of changes to the underlying prevalence. These simple methods not only demonstrate geographic portability, but the results reassure the public health effort towards monitoring and controlling chlamydia.

Typing Chlamydia trachomatis: from egg yolk to nanotechnology

A historical review is provided of the various methods used for half a century to differentiate and type Chlamydia trachomatis strains. Typing of C. trachomatis is an important tool for revealing transmission patterns in sexual networks, and enabling association with clinical manifestations and pathogenicity. Serotyping using the major outer membrane protein (MOMP) has been the mainstay of epidemiological work for several decades. However, the development of nucleic acid amplification techniques (NAAT) and easy access to sequencing have shifted the focus from MOMP serotypes to omp1 genotypes. However, insufficient epidemiological resolution is achieved by characterization of both MOMP and omp1. This calls for new high-resolution genotyping methods applying for example a multilocus variable number tandem repeat assay (MLVA) or multilocus sequence typing (MLST). The futuristic nanotechnology already seems at hand to further simplify and automate the high-resolution genotyping method based on NAAT and sequencing of various targets in the C. trachomatis genome. Thereby, a high throughput can be achieved and more epidemiological information can be obtained. However, it is important to realize that culture of C. trachomatis may still be needed to detect and characterize new variants of C. trachomatis.

Chlamydia trachomatis infections in norway, 1986 to 2006, surveillance data

INTRODUCTION

The number of Chlamydia trachomatis infections in Norway has been increasing for the last years. A new and enhanced surveillance system was implemented in 2005 to meet the challenges faced by the increasing number of cases.

METHODS

The new surveillance system is laboratory based. Data are collected once a year from all laboratories on the total number of test performed, and all diagnosed cases from the preceding year. For each case the following variables are reported: date of diagnosis, birth year, sex, and municipality of residence.

RESULTS

By 2006 all laboratories reported data as required. We have observed an increase in yearly diagnosed C. trachomatis cases in Norway during the last years. In 2006, the incidence was 4.6 per 1000 population. The proportion positive tests have increased from 6.0% in 2000 to 7.7% in 2006. In the same period the annual number of tests increased by 13.5%. Surveillance data from 2006 showed that the highest incidence rates were found in women between the ages of 15 to 24 in men aged 20 to 24 and in 2 northernmost regions of the country.

CONCLUSION

The year 2006 had the highest level of diagnosed cases ever in Norway. To better interpret the observed trend, a voluntary system will be introduced in 2007 to collect test rates by age, gender and geography. There is a need to evaluate current and new strategies to target the group of asymptomatic and untreated young people.

The implementation of European Association of Urology guidelines in the management of acute epididymo-orchitis

INTRODUCTION

Acute epididymo-orchitis is a common and increasing problem. This retrospective study reviewed whether the European Association of Urology guidelines for the management of acute epididymo-orchitis, which form the basis of this Trust's present inter-departmental guidelines, are being effectively implemented.

PATIENTS AND METHODS

Case notes of 53 patients attending the emergency department with acute epididymo-orchitis over a 6-month period were reviewed retrospectively. The hospital results' database was used to confirm the diagnostic tests requested on patients at the time of their initial presentation.

RESULTS

Of the study cohort, 26 patients were aged </= 35 years and 27 patients were aged > 35 years. The results demonstrated that a sexual history was documented in only 43.4% of cases. A mid-stream urine sample was sent for routine culture in 54.7% of cases whilst urine for the Chlamydia polymerase chain reaction (PCR) test was obtained in 17% and a urethral swab performed in 5.6%. Antibiotics were prescribed in 81% of cases. Of these patients, 46.5% received ciprofloxacin alone (mean age, 52 years; range, 18-87 years), 25.5% received doxycycline alone (mean age, 30 years; range, 18-45 years) and 21% received both ciprofloxacin and doxycycline (mean age, 33 years; range 18-49 years). In 26.4% of cases, verbal advice to attend a genito-urinary medicine clinic was given, whilst a formal telephone referral was made in only one case. Formal urological follow-up was arranged for only three out of 11 patients aged > 50 years.

CONCLUSIONS

Although a joint emergency department/urology clinical protocol for the investigation and treatment of acute epididymo-orchitis already exists within the Trust, our current management conforms to this in only a minority of cases. Many different strategies can be employed in the implementation of clinical practice guidelines and all are associated with variable degrees of success. The regular movement of junior staff through each department necessitates that the distribution of management protocols and guidelines occurs at frequent intervals throughout the year and that their implementation is continuously monitored so that, if necessary, further implementation strategies can be employed.