Evaluation of the Latent Tuberculosis Care Cascade Among Public Health Clinics in the United States.

BACKGROUND: Tuberculosis (TB) elimination within the United States will require scaling up TB preventive services. Many public health departments offer care for latent tuberculosis infection (LTBI), although gaps in the LTBI care cascade are not well quantified. An understanding of these gaps will be required to design targeted public health interventions. METHODS: We conducted a cohort study through the Tuberculosis Epidemiologic Studies Consortium (TBESC) within 15 local health department (LHD) TB clinics across the United States. Data were abstracted on individuals receiving LTBI care during 2016-2017 through chart review. Our primary objective was to quantify the LTBI care cascade, beginning with LTBI testing and extending through treatment completion. RESULTS: Among 23 885 participants tested by LHDs, 46% (11 009) were male with a median age of 31 (interquartile range [IQR] 20-46). A median of 35% of participants were US-born at each site (IQR 11-78). Overall, 16 689 (70%) received a tuberculin skin test (TST), 6993 (29%) received a Quantiferon (QFT), and 1934 (8%) received a T-SPOT.TB; 5% (1190) had more than one test. Among those tested, 2877 (12%) had at least one positive test result (3% among US-born, and 23% among non-US-born, P < .01). Of 2515 (11%) of the total participants diagnosed with LTBI, 1073 (42%) initiated therapy, of whom 817 (76%) completed treatment (32% of those with LTBI diagnosis). CONCLUSIONS: Significant gaps were identified along the LTBI care cascade, with less than half of individuals diagnosed with LTBI initiating therapy. Further research is needed to better characterize the factors impeding LTBI diagnosis, treatment initiation, and treatment completion.

Impact of T-Cell Xtend on T-SPOT.TB Assay in High-Risk Individuals after Delayed Blood Sample Processing.

T-SPOT.TB (T-SPOT) is an interferon gamma release assay (IGRA) used to detect infection with Mycobacterium tuberculosis based on the number of spot-forming T cells; however, delays in sample processing have been shown to reduce the number of these spots that are detected following laboratory processing. Adding T-Cell Xtend (XT) into blood samples before processing reportedly extends the amount of time allowed between blood collection and processing up to 32 h. In this study, paired blood samples from 306 adolescents and adults at high risk for latent tuberculosis (TB) infection (LTBI) or progression to TB disease were divided into three groups: (i) early processing (∼4.5 h after collection) with and without XT, (ii) delayed processing (∼24 h after collection) with and without XT, and (iii) early processing without XT and delayed processing with XT. The participants' paired samples were processed at a local laboratory and agreement of qualitative and quantitative results was assessed. The addition of XT did not consistently increase or decrease the number of spots. In groups 1, 2, and 3, samples processed with XT had 13% (10/77), 28.0% (30/107), and 24.6% (30/122), respectively, more spots, while 33.8% (26/77), 26.2% (28/107), and 38.5% (47/122) had fewer spots than samples processed without XT. The findings suggest that XT does not reliably mitigate the loss of spot-forming T cells in samples with processing delay.

Genomic sequencing is required for identification of tuberculosis transmission in Hawaii.

BACKGROUND: Tuberculosis (TB) caused an estimated 1.4 million deaths and 10.4 million new cases globally in 2015. TB rates in the United States continue to steadily decline, yet rates in the State of Hawaii are perennially among the highest in the nation due to a continuous influx of immigrants from the Western Pacific and Asia. TB in Hawaii is composed of a unique distribution of genetic lineages, with the Beijing and Manila families of Mycobacterium tuberculosis (Mtb) comprising over two-thirds of TB cases. Standard fingerprinting methods (spoligotyping plus 24-loci Mycobacterial Interspersed Repetitive Units-Variable Number Tandem Repeats [MIRU-VNTR] fingerprinting) perform poorly when used to identify actual transmission clusters composed of isolates from these two families. Those typing methods typically group isolates from these families into large clusters of non-linked isolates with identical fingerprints. Next-generation whole-genome sequencing (WGS) provides a new tool for molecular epidemiology that can resolve clusters of isolates with identical spoligotyping and MIRU-VNTR fingerprints. METHODS: We performed WGS and SNP analysis and evaluated epidemiological data to investigate 19 apparent TB transmission clusters in Hawaii from 2003 to 2017 in order to assess WGS' ability to resolve putative Mtb clusters from the Beijing and Manila families. This project additionally investigated MIRU-VNTR allele prevalence to determine why standard Mtb fingerprinting fails to usefully distinguish actual transmission clusters from these two Mtb families. RESULTS: WGS excluded transmission events in seven of these putative clusters, confirmed transmission in eight, and identified both transmission-linked and non-linked isolates in four. For epidemiologically identified clusters, while the sensitivity of MIRU-VNTR fingerprinting for identifying actual transmission clusters was found to be 100%, its specificity was only 28.6% relative to WGS. We identified that the Beijing and Manila families' significantly lower Shannon evenness of MIRU-VNTR allele distributions than lineage 4 was the cause of standard fingerprinting's poor performance when identifying transmission in Beijing and Manila family clusters. CONCLUSIONS: This study demonstrated that WGS is necessary for epidemiological investigation of TB in Hawaii and the Pacific.

TB-free Ebeye: Results from integrated TB and noncommunicable disease case finding in Ebeye, Marshall Islands.

Background: Tuberculosis (TB) incidence rates in the Republic of the Marshall Islands are among the highest in the world, 480/100,000 in 2017. In response, the Health Ministry completed islandwide screening in Ebeye Island in 2017. Methods: Participants were interviewed to obtain TB history, exposures, and symptoms. TB assessment included chest radiography with sputum collection for GeneXpert® MTB-RIF if indicated. TB diagnosis was made by consensus of visiting TB experts. Participants were also screened for Hansen's disease (HD) and diabetes mellitus (DM). For persons aged ≥21 years, blood pressure, cholesterol, and blood glucose were assessed. Results: A total of 5,166 persons (90.0 % of target population) completed screening leading to the identification of 39 new cases of TB (755/100,000) and 14 persons with HD (270/100,000). DM was detected in 1,096 persons (27 %), including in 351 persons not previously diagnosed. The rate of hypertension was 61 % and of hypercholesterolemia was 15 %. New or prevalent TB diagnosis was associated with newly diagnosed or history of DM (aOR 4.68, 2.15-10.20). Conclusions: In Ebeye, an integrated TB screening campaign found TB, HD, DM, and hypertension. TB and DM were strongly associated.

Estimating the long-term effects of mass screening for latent and active tuberculosis in the Marshall Islands.

BACKGROUND: Ambitious population-based screening programmes for latent and active tuberculosis (TB) were implemented in the Republic of the Marshall Islands in 2017 and 2018. METHODS: We used a transmission dynamic model of TB informed by local data to capture the Marshall Islands epidemic's historical dynamics. We then used the model to project the future epidemic trajectory following the active screening interventions, as well as considering a counterfactual scenario with no intervention. We also simulated future scenarios including periodic interventions similar to those previously implemented, to assess their ability to reach the End TB Strategy targets and TB pre-elimination in the Marshall Islands. RESULTS: The screening activities conducted in 2017 and 2018 were estimated to have reduced TB incidence and mortality by around one-third in 2020, and are predicted to achieve the End TB Strategy milestone of 50% incidence reduction by 2025 compared with 2015. Screening interventions had a considerably greater impact when latent TB screening and treatment were included, compared with active case finding alone. Such combined programmes implemented at the national level could achieve TB pre-elimination around 2040 if repeated every 2 years. CONCLUSIONS: Our model suggests that it would be possible to achieve TB pre-elimination by 2040 in the Marshall Islands through frequent repetition of the same interventions as those already implemented in the country. It also highlights the importance of including latent infection testing in active screening activities.

A systematic review of hepatitis C virus epidemiology in Europe, Canada and Israel.

BACKGROUND AND AIM: Decisions on public health issues are dependent on reliable epidemiological data. A comprehensive review of the literature was used to gather country-specific data on risk factors, prevalence, number of diagnosed individuals and genotype distribution of the hepatitis C virus (HCV) infection in selected European countries, Canada and Israel. METHODOLOGY: Data references were identified through indexed journals and non-indexed sources. In this work, 13,000 articles were reviewed and 860 were selected based on their relevance. RESULTS: Differences in prevalence were explained by local and regional variances in transmission routes or different public health measures. The lowest HCV prevalence (≤ 0.5%) estimates were from northern European countries and the highest (≥ 3%) were from Romania and rural areas in Greece, Italy and Russia. The main risk for HCV transmission in countries with well-established HCV screening programmes and lower HCV prevalence was injection drug use, which was associated with younger age at the time of infection and a higher infection rate among males. In other regions, contaminated glass syringes and nosocomial infections continue to play an important role in new infections. Immigration from endemic countries was another factor impacting the total number of infections and the genotype distribution. Approximately 70% of cases in Israel, 37% in Germany and 33% in Switzerland were not born in the country. In summary, HCV epidemiology shows a high variability across Europe, Canada and Israel. CONCLUSION: Despite the eradication of transmission by blood products, HCV infection continues to be one of the leading blood-borne infections in the region.

A systematic review of hepatitis C virus epidemiology in Asia, Australia and Egypt.

BACKGROUND: The hepatitis C pandemic has been systematically studied and characterized in North America and Europe, but this important public health problem has not received equivalent attention in other regions. AIM: The objective of this systematic review was to characterize hepatitis C virus (HCV) epidemiology in selected countries of Asia, Australia and Egypt, i.e. in a geographical area inhabited by over 40% of the global population. METHODOLOGY: Data references were identified through indexed journals and non-indexed sources. In this work, 7770 articles were reviewed and 690 were selected based on their relevance. RESULTS: We estimated that 49.3-64.0 million adults in Asia, Australia and Egypt are anti-HCV positive. China alone has more HCV infections than all of Europe or the Americas. While most countries had prevalence rates from 1 to 2% we documented several with relatively high prevalence rates, including Egypt (15%), Pakistan (4.7%) and Taiwan (4.4%). Nosocomial infection, blood transfusion (before screening) and injection drug use were identified as common risk factors in the region. Genotype 1 was common in Australia, China, Taiwan and other countries in North Asia, while genotype 6 was found in Vietnam and other Southeast Asian countries. In India and Pakistan genotype 3 was predominant, while genotype 4 was found in Middle Eastern countries such as Egypt, Saudi Arabia and Syria. CONCLUSION: We recommend implementation of surveillance systems to guide effective public health policy that may lead to the eventual curtailment of the spread of this pandemic infection.

Higher Rates of Tuberculosis Among Class B1 Filipino Immigrants to Hawaii Compared to Nationwide, 2010-2014.

BACKGROUND: Immigrants to the United States from countries with a high burden of tuberculosis (TB) who have abnormal chest radiographs but negative sputum cultures during pre-immigration screening (TB Class B1) have a high risk of being diagnosed with TB disease within 1 year of arrival. METHODS: Using 2010-2014 national surveillance data, we compared proportions of Class B1 Filipino immigrants who received a diagnosis of TB disease within 1 year of arrival to Hawaii to proportions in other U.S. states (not including Hawaii) using chi-squared tests. RESULTS: In Hawaii, 40/1190 (3.4%) of Class B1 Filipino immigrants to Hawaii received a diagnosis of TB disease within 1 year of arrival compared with 220/16,035 (1.4%) nationwide (P < .01). CONCLUSIONS: During 2010-2014, the percentage of recent Class B1 Filipino immigrants in Hawaii with TB disease diagnosed within 1 year of arrival was over twice that as nationwide.

Whole genome SNP analysis suggests unique virulence factor differences of the Beijing and Manila families of Mycobacterium tuberculosis found in Hawaii.

While tuberculosis (TB) remains a global disease, the WHO estimates that 62% of the incident TB cases in 2016 occurred in the WHO South-East Asia and Western Pacific regions. TB in the Pacific is composed predominantly of two genetic families of Mycobacterium tuberculosis (Mtb): Beijing and Manila. The Manila family is historically under-studied relative to the families that comprise the majority of TB in Europe and North America (e.g. lineage 4), and it remains unclear why this lineage has persisted in Filipino populations despite the predominance of more globally successful Mtb lineages in most of the world. The Beijing family is of particular interest as it is increasingly associated with drug resistance throughout the world. Both of these lineages are important to the State of Hawaii, where they comprise over two-thirds of TB cases. Here, we performed whole genome sequencing on 82 Beijing family, Manila family, and outgroup clinical Mtb isolates from Hawaii to identify lineage-specific SNPs (SNPs found in all isolates from their respective families, and exclusively in those families) in established virulence factor genes. Six non-silent lineage-specific virulence factor SNPs were found in the Beijing family, including mutations in alternative sigma factor sigG and polyketide synthases pks5 and pks7. The Manila family displayed more than eleven non-silent lineage-specific and characteristic virulence factor mutations, including in genes coding for MCE-family protein Mce1B, two mutations in fatty-acid-AMP ligase FadD26, and virulence-regulating transcriptional regulator VirS. This study further identified an ancient clade that shared some virulence factor mutations with the Manila family, and investigated the relationship of those and other "Manila-like" spoligotypes to the Manila family with this SNP dataset. This work identified a set of virulence genes that are worth pursuing to determine potential differences in transmission or virulence displayed by these two Mtb families.

Circadian organization of a subarctic rodent, the northern red-backed vole (Clethrionomys rutilus).

Arctic and subarctic environments are exposed to extreme light: dark (LD) regimes, including periods of constant light (LL) and constant dark (DD) and large daily changes in day length, but very little is known about circadian rhythms of mammals at high latitudes. The authors investigated the circadian rhythms of a subarctic population of northern red-backed voles (Clethrionomys rutilus). Both wild-caught and third-generation laboratory-bred animals showed predominantly nocturnal patterns of wheel running when exposed to a 16:8 LD cycle. In LL and DD conditions, animals displayed large phenotypic variation in circadian rhythms. Compared to wheel-running rhythms under a 16:8 LD cycle, the robustness of circadian activity rhythms decreased among all animals tested in LL and DD (i.e., decreased chi-squared periodogram waveform amplitude). A large segment of the population became noncircadian (60% in DD, 72% in LL) within 8 weeks of exposure to constant lighting conditions, of which the majority became ultradian, with a few individuals becoming arrhythmic, indicating highly labile circadian organization. Wild-caught and laboratory-bred animals that remained circadian in wheel running displayed free-running periods between 23.3 and 24.8 h. A phase-response curve to light pulses in DD showed significant phase delays at circadian times 12 and 15, indicating the capacity to entrain to rapidly changing day lengths at high latitudes. Whether this phenotypic variation in circadian organization, with circadian, ultradian, and arrhythmic wheel-running activity patterns in constant lighting conditions, is a novel adaptation to life in the arctic remains to be elucidated.