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Results for “Space-Time Clustering”

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At least 19 recordsLinked to original sources
PubMed2026

Spatial clustering and transmission networks of multidrug-resistant tuberculosis in Rwanda: a national retrospective genomic and spatial epidemiological study.

BACKGROUND: Approximately 96% of rifampicin resistance/multidrug-resistant tuberculosis (RR/MDR-TB) cases in Rwanda result from direct transmission rather than acquired resistance. However, the nationwide spatial distribution and transmission dynamics of RR/MDR-TB remain poorly characterised. This study aims to analyse spatial patterns of RR/MDR-TB in Rwanda and explore relationships between spatial proximity and RR/MDR-TB strains' genetic relatedness. METHODS: We conducted a retrospective analysis of 249 confirmed RR-TB cases across Rwanda from 2017 to 2024, using the known geolocations of patients' residences. Spatial and space-time clustering was assessed using Kulldorff's scan statistics. Demographic and socioeconomic determinants were evaluated using multivariable regression. For 201 cases with whole-genome sequencing data, we performed transmission analysis using a 5-SNP threshold to define recent transmission clusters and investigated spatial relationships within genetically related strains. RESULTS: Significant spatial clustering of RR/MDR-TB was identified in 21 sectors, mainly in Nyarugenge, southern Gasabo and western Kicukiro (relative risk: 10.06; p<0.001). Our multivariable analysis showed that population density is positively associated with case notification rates. Molecular analysis revealed 88.5% of cases belonged to genotype clusters defined using a 12-SNP threshold, with 73.6% forming clusters at a strict 5-SNP threshold. Spatial K-function analysis of the six major clusters revealed heterogeneous transmission patterns, characterised by both tightly clustered outbreaks and regional transmission networks that spanned administrative boundaries. Most clusters (5/6) extended beyond Kigali, indicating that transmission networks operate across administrative divides. CONCLUSION: RR/MDR-TB in Rwanda shows significant spatial clustering with transmission occurring through both localised and regional networks. Integrating genomic and spatial data reveals transmission patterns that extend beyond household contacts and administrative boundaries. These findings underscore the need to implement geographically targeted interventions that address community-level transmission to control RR/MDR-TB in Rwanda effectively.

Rwanda↗
PubMed1977

Trisomy clusters.

Explore the source record for details and available documents.

Colorado↗
PubMedDate not supplied

A detection algorithm for multiform premature ventricular contractions.

This paper reports an algorithm developed to identify and quantify multiform PVCs. The algorithm clusters PVCs of similar morphology using a combination of time-domain and frequency-domain analysis. Initially, PVCs are grouped together on the basis of four time-domain-based morphological feature measurements. However, these time-domain-based clusters many times are nonunique because commonly encountered signal changes can cause substantial variations in the feature measurements of clinically similar beats. These redundant clusters are consolidated using two frequency-domain parameters: The First Spectral Moment (FSM) (center of gravity) of the amplitude spectrum, and the 5-Hz phase angle.

Cardiac Complexes, Premature↗
PubMed1978

Clustering of different subtypes of hepatitis B surface antigen in families of patients with chronic liver diseases.

Clustering of hepatitis B surface antigen (HBsAg) with both subtypes adr and adw in three families of patients with chronic liver diseases or hepatocellular carcinoma was demonstrated in Taiwan where adw is the main subtype. The subtype in the children was similar to that in their mothers, suggesting maternal transmission. In all the family units clustered with different subtypes, the same pattern occurred, invariably with fathers carrying HBsAg/adr and the children carrying HBsAg/adw. The subtype difference clearly rules out the transmission of hepatitis B virus (HBV) from father. Horizontal infection with the locally dominant adw-subtyped HBV in the children of fathers carrying HBsAg/adr explains the discrepancy of the subtypes in these families. Clustering of two HBsAg-positive brothers with hepatocellular carcinoma in one of the families was found. That both adr-subtyped and adw-subtyped HBV are capable of inducing chronic active hepatitis in another family suggests that host factors are probably more important in determining the clinical course of HBV infection.

Adult↗
PubMed1979

[Studies of parodontal results obtained for selected teeth and groups of teeth with particular reference to their predictive potential regarding an overall assessment (author's transl)].

With the support of a Cluster Analysis and other statistical methods we have found out the relative efficiency of some periodontal partial recording selections. Overrating or underrating evaluations arise from the registration of periodontal symptoms and signs by partial recording of special teeth or groups of teeth. The results of our investigations have demonstrated the higher quantitative and qualitative coincidence of the RAMFJORDS teeth with the periodontal status as the frontal region of the lower jaw.

Dental Calculus↗
PubMed1979

Incidence of myeloid leukaemia in Lancashire.

Identification of a "cluster" of cases of acute myeloid leukaemia and chronic myeloproliferative disorders in Lytham St. Annes, Lancashire, prompted an analysis of the incidence of myeloid leukaemias in Lancashire (excluding Ormskirk Health District), as recorded by the Manchester Cancer Registry. Although statistically there was no significant difference in the trend of incidence between the whole former borough of Lytham St. Annes and the other districts studied, the reported incidence of these diseases in the area as a whole had almost doubled, and in two districts nearly trebled, between two consecutive 6 year periods, beginning in 1965. This represents a substantially larger increase than mortality data suggests has occurred nationally in the same period, and is unlikely to be due solely to more accurate diagnosis or reporting.

England↗
PubMed1978

Multivariate analyses of the MMPI profiles of low back pain patients.

A multivariate clustering procedure was used to identify replicable, homogeneous MMPI profile subgroups among three independent cohorts of male (N = 233) and female (N = 315) low back pain ((LBP) patients. Three subgroups were replicated across all male cohorts and four subgroups were replicated across all female cohorts. Multiple discriminant analysis showed that for both male and female patients between-subgroup variability was significantly greater than within-subgroup variability. The results suggest that LBP patients may not be solely characterized by MMPI profiles featuring the "conversion V" configuration. Examination of the profile subgroups also suggests there may be distinct, pain-related, behavioral attributes associated with each subgroup which might have important implications for practitioners' choice of treatment modalities. Suggestions are made for research regarding the development of specific, optimal treatments for various LBP patient subgroups.

Analysis of Variance↗
PubMed1978

Paralytic poliomyelitis in England and Wales 1976-7.

In 1976-7 26 cases of paralytic poliomyelitis were notified, of which 6 were vaccine-associated. 16 of the 20 non-vaccine-associated cases were due to type-u poliovirus, the type usually associated with outbreaks. The most important factor in the increase was the occurrence of poliomyelitis in unvaccinated persons.

Adult↗
PubMed1978

Multiple sclerosis and canine distemper in Iceland.

Iceland offers a favourable opportunity to examine the suggested relationship between canine distemper and multiple sclerosis. Distemper is not enzootic in Iceland and distemper immunisation is not practised. However, importations result in occasional epizootics, three of which have occurred since 1909. Careful enumeration of multiple sclerosis indicates that there were 129 cases during the period 1946--65. When these cases are subdivided into six regions, by place of birth, regional period-prevalence rates were highest in two regions partially involved by distemper only once in the past 70 years. Also, there was substantial prevalence in a third region, encompassing Reykjavik, where the dog population has been kept very low for over 50 years. The Icelandic experience indicates that multiple sclerosis can occur at high incidence in the virtual absence of canine distemper or in the presence of a very small dog population.

Animals↗
PubMedDate not supplied

A two-dimensional clustering technique for identification of multiform ventricular complexes.

A computer algorithm for the identification of multiform ectopic ventricular complexes in 24-hour ambulatory electrocardiographic recordings is described. The clustering technique established regions, based on R-R interval and ST-segment slope, in a two-dimensional probability space based on the fit of each ventricular complex. The boundaries of any overlapping regions are analyzed using a Bayesian decision rule to minimize misclassification.

Arrhythmias, Cardiac↗
PubMed2026

Mapping Sub-National Respiratory Virus Circulation in Cambodia Using Metatranscriptomic Sequencing: A Multi-Center Hospital-Based Surveillance Study.

BACKGROUND: Genomic surveillance can guide early detection of and response to emerging epidemics. Metatranscriptomic sequencing was used to investigate sub-national respiratory virus circulation in Cambodia from 2020 to 2023. METHODS: Nasopharyngeal swabs were collected from individuals aged 2&#x2009;months to 65&#x2009;years with influenza-like illness in four Cambodian hospitals. Metatranscriptomic data were generated by short-read RNA sequencing. Bernoulli space-time scan statistics were used to identify temporal virus clusters. Bayesian inference of phylogenetic trees was used to compute divergence times for temporally clustered, highly represented viruses (influenza A/H3N2 and B, Betacoronavirus 1, respiratory syncytial virus [RSV] A and B), and publicly available global influenza virus genomes. RESULTS: Of 1093 individuals, 499 (45.7%) had detectable respiratory viruses belonging to 68 distinct species. Moderate (N&#x2009;>&#x2009;20) discrete time-clusters were noted of RSV-A (37 cases), Betacoronavirus 1 (21 cases), RSV-B (22 cases), and A/H3N2 (30 cases). The posterior median of time to most recent common ancestor ranged from 0.71&#x2009;years (95% HPD 0.38-1.10) for Betacoronavirus 1 and 1.31&#x2009;years (95% HPD 0.60-3.20) for A/H3N2, to 2.75&#x2009;years (1.82-4.26) for RSV-A and 4.79&#x2009;years (2.39-7.74) for RSV-B. A/H3N2 and influenza B virus genomes mapped to clades 3C.2a1b.2a.2a and Victoria 1A.3a.2, respectively, and inter-mixed with concurrent global strains. CONCLUSIONS: Multiple respiratory viruses circulated at a sub-national level in Cambodia from 2020 to 2023 despite pandemic disruptions. Influenza virus population diversity decreased during the height of lockdown but recovered in mid-2022. Re-emerging influenza strains were distinct from historically circulating strains and clustered with contemporaneous global variants, suggesting multiple external introductions.

Humans↗