Genome-based transmission modelling separates imported tuberculosis from recent transmission within an immigrant
Diepreye Ayabina1, Janne O Ronning2, Kristian Alfsnes2
11Department of Mathematics, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
Microbial Genomics
|September 15, 2018
Summary
Tuberculosis (TB) transmission in Norway is complex, with most cases among immigrants. Whole-genome sequencing revealed about a quarter of TB infections occurred within Norway, not solely imported.
Area of Science:
- Genomics
- Epidemiology
- Infectious Disease Control
Background:
- Low tuberculosis (TB) incidence countries often see TB cases concentrated in immigrant populations from high-burden regions.
- Norway experiences over 80% of TB cases among immigrants, posing challenges for distinguishing imported vs. local transmission due to factors like variable latency and social networks.
Purpose of the Study:
- To investigate the transmission dynamics of Mycobacterium tuberculosis in Norway, specifically within an immigrant community.
- To differentiate between imported TB cases and within-country transmission using genomic data.
Main Methods:
- Whole-genome sequencing of clinical Mycobacterium tuberculosis isolates.
- Phylogenetic analysis to model transmission and estimate patient infection times.
- Comparison of estimated infection times with patient arrival dates in Norway.
Main Results:
- A large genotype cluster linked to the Horn of Africa was identified in Norway over two decades.
- Independent import accounted for the majority of TB cases.
- Approximately 25% of TB cases were estimated to have been acquired within Norway.
Conclusions:
- While import is the primary driver, a significant proportion of TB transmission occurs locally within immigrant communities in low-incidence settings.
- The genomic and temporal analysis approach is valuable for understanding TB transmission dynamics and informing control strategies in diverse populations.
Related Concept Videos
01:25Transmission-based Precautions II: Airborne and Protective Environment
2.0K
Transmission-based precautions are for patients infected or suspected to be infected (or colonized) with organisms posing a significant risk to others. The transmission precautions include airborne and protective environment precautions.
Airborne precautions:
Use airborne precautions when treating patients known or suspected to have diseases that spread through the air—for example, tuberculosis or measles. These organisms are present in smaller droplets expelled by an infected person and...
Airborne precautions:
Use airborne precautions when treating patients known or suspected to have diseases that spread through the air—for example, tuberculosis or measles. These organisms are present in smaller droplets expelled by an infected person and...
2.0K
01:17Transmission-based Precautions I: Contact, Enteric, and Droplets
4.6K
Transmission-based precautions are for patients known to be infected or suspected to be infected or colonized with organisms that pose a significant risk to others. Some transmission-based precautions include contact, enteric, and droplet.
Contact Precautions:
Contact precautions are the measures taken to prevent the transmission of infectious agents, especially epidemiologically important microorganisms such as MRSA or influenza, primarily transmitted through direct or indirect contact with an...
Contact Precautions:
Contact precautions are the measures taken to prevent the transmission of infectious agents, especially epidemiologically important microorganisms such as MRSA or influenza, primarily transmitted through direct or indirect contact with an...
4.6K
01:16Design of Transmission Shafts
786
The design of a transmission shaft is governed by two primary specifications: the power it transmits and its rotational speed. These parameters guide the selection of the shaft's material and cross-sectional dimensions, ensuring that the material's maximum shearing stress remains within the elastic limit while transmitting the desired power at the given speed. The system's power is intrinsically linked to the applied torque. The torque applied to the shaft can be calculated by reconfiguring the...
786
01:23Transmission Line Design Considerations
631
Aluminum has become the material of choice for overhead transmission lines, surpassing copper due to its abundance and cost-effectiveness. The most prevalent type is the aluminum conductor, steel-reinforced (ACSR), which combines aluminum strands around a steel core. Other variants include all-aluminum conductors (AAC), all-aluminum alloy conductors (AAAC), aluminum conductor alloy-reinforced (ACAR), and aluminum-clad steel conductors. Advanced designs, such as aluminum conductors with steel...
631
01:09Transmission Shafts: Problem Solving
514
Designing a solid shaft that transmits power from a motor to a machine tool involves a series of calculations to ensure the shaft can withstand the stresses applied by bending moments and torques. First, calculate the torque exerted on the gear, considering the power transmitted by the shaft and its rotational speed. Following this, compute the tangential forces acting on the gears, which directly relate to the torque and the gear radius.
Next, use bending moment diagrams for the shaft to...
Next, use bending moment diagrams for the shaft to...
514
01:26Transmission-Line Differential Equations
1.0K
Transmission lines are essential components of electrical power systems. They are characterized by the distributed nature of resistance (R), inductance (L), and capacitance (C) per unit length. To analyze these lines, differential equations are employed to model the variations in voltage and current along the line.
Line Section Model
A circuit representing a line section of length Δx helps in understanding the transmission line parameters. The voltage V(x) and current i(x) are measured from...
Line Section Model
A circuit representing a line section of length Δx helps in understanding the transmission line parameters. The voltage V(x) and current i(x) are measured from...
1.0K