Htin's lecture Flashcards
what is equality?
this is considered to be equal treatment
based on the assumption is that everyone benefits from the same supports
what is equity?
everyone getting the support that they need produces equity
what is mate kohi/tuberculosis?
the disease caused by mycobacterium tuberculosis
strongly related with poverty (most low burden countries are developed)
kills someone on average every 20 seconds
what are the phases of TB infection?
exposure to Mtb from active TB individuals leads to infection of 25% individuals
of those initially infected less than 10% experience early progression due to failed immune control leading to active TB
of those initially infected over 90% get latent infection as host immune system controls infection so it doesn’t progress; 10% of these individuals experience reactivation at some point due to failed immune control leading to active TB
what things increase chance of TB?
host - malnutrition, diabetes, HIV, smoking, alcohol, genetics
health services - delayed diagnosis, delayed treatment
pathogen - genetics, lineage, drug resistance, co-infections
environment - crowding, poor ventilation, indoor air pollution, congregate settings, occupational exposures
hence why combatting TB requires an interdisciplinary approach
what is the multisectoral approach?
interdisciplinary research involving the likes of academics, health economists, clinicians, social scientists, epidemiologists as well as policymakers and communities
community engagement is crucial as if you don’t engage communities how will you know the research is meeting their needs
what is mycobacterium tuberculosis?
small bacteria with small genome
mycobacterium tuberculosis complex (MTBC) are a group of the mycobacterium species with very little SNP differences between lineages
clonal, no HGT and slow mutation rate
5 or less SNP difference - cases linked
6-12 SNP difference - cases probably linked
what are the different kinds of sequencing technologies?
sequencing is the process of determining the order of nucleotide bases along a DNA strand
first-generation sequencing e.g. Sanger sequencing
next-generation sequencing e.g. Illumina
third-generation sequencing e.g. nanopore
different chemistry between different sequencing technologies
how do you interpret a phylogenetic tree?
whole genome sequencing data can organise sequences into lineages based on differences in SNPs which are represented as dots
can identify clusters based on SNP differences; less than 12 SNP differences between cases can be considered a cluster
very useful to delineate Mtb outbreaks
what data is combined to identify clusters during TB outbreaks?
genome sequencing data
epidemiological data
spatial data
how has tuberculosis fared in NZ?
TB notification rates have dropped dramatically following the national TB campaign
this coincided with the tuberculosis act 1948 which introduced consequences for those refusing to undergo treatment, the use of chest x-rays to identify TB becoming widespread in the 1950’s as well as BCG vaccination
notification rates have continued to drop with the introduction of new public health measures such as TB screening for international students staying for over 6 months (2004)
what are the two main variants of Mtb circulating in NZ and how do they highlight socioeconomic inequities?
rangipo strain strongly associated with Māori communities
southern cross strain strongly associated with Pasifika communities
Māori - 6 TB cases per 100,000
Pasifika - 16 TB cases per 100,000
Pākehā - 1 TB case per 100,000
indigenous populations also disproportionately effected in other countries native Americans, aborigines
how can we identify ongoing community transmission of TB?
identifying TB cases with no epidemiological link to other known cases
5 SNP differences can be considered a linked case, 12 or less means probably linked case
stopping ongoing community transmission is complicated by latent TB infections which grow slowly and have low mutation rates
what rapid diagnostic test do we have for TB and what NZ strain is it crucial for?
a fast and robust test for Rangipo strain is important to control further transmission due to evidence suggesting it is highly transmissible and confers faster disease progression
WGS guided, SNP based PCR-RFLP diagnostic can identify rangipo strain based on the number of bands that is run on gel
this has proven vital to combatting previous rangipo strain outbreaks such as in Kāwhia, cutting down diagnostic times by 3-4 weeks
what are high TB burden countries?
countries experiencing high rates of TB e.g. Myanmar, China, India
eight countries ranking first in terms of case numbers make up two thirds of global cases
huge problem is emergence of MDR and XDR-TB which have considerably longer and more complicated treatment (6mths vs 2 years) and are considerably more expensive (12,000NZD vs 330,000NZD) - much worse treatment outcomes as well
TB acquires drug resistance due to suboptimal treatment and poor adherence to treatment regimens, this DR-TB can then spread to other individuals who were previously uninfected as drug naive TB (primary resistance - as opposed to acquired resistance)
this is largely due to high burden countries having less treatment accountability and limited social welfare systems
WGS, rapid diagnostics and phylogenetic analysis are crucial to getting TB under control in these areas
