Typhoid fever is a systemic illness that causes fever. It is spread through faeces and food or water, mostly in the developing world.
At least 16–20 million people get typhoid fever each year around the world, and about 600,000 of them die.
S. typhi is different from the other 2300 serovars of S. enterica subs. enterica because it is only able to infect people.
Given that S. typhi is so specific to humans, it could be younger than the split between humans and higher primates a few million years ago. It could also be younger than the spread of anatomically modern humans from Africa about 50,000 to 100,000 years ago.
S. enterica and Escherichia coli had their last common ancestor about 140 million years ago, but no one knows how old S. typhi is yet.
By using pulsed-field gel electrophoresis, IS200 typing, ribotyping, and amplified fragment length polymorphism, it has been shown that the S. typhi population has a lot of genetic diversity.
All of these fingerprinting methods found different fingerprints that were thought to be from different clones. This suggests that S. typhi is quite diverse.
There have been cases of typhoid outbreaks caused by a single PFGE genotype, but sporadic disease in endemic areas is usually linked to more than one PFGE genotype.
S. typhi isolates can have genome sizes that are up to 20% (1 MB) different from each other. This suggests that there has been a long history of insertions, deletions, and/or horizontal genetic exchange.
Also, unlike other serovars of S. enterica, the order of genes in S. typhi is not fixed. This is because homologous recombination between rRNA genes can cause rearrangements.
Kidgell, Claire & Reichard, Ulrike & Wain, John & Linz, Bodo & Torpdahl, Mia & Dougan, Gordon & Achtman, Mark. (2002). Salmonella Typhi, the causative agent of typhoid fever, is approximately 50,000 years old.. Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases. 2. 39-45. 10.1016/S1567-1348(02)00089-8.
We hope you've enjoyed reading our latest blog article! We're thrilled to see the positive response it's been
receiving so far. We understand that sometimes, after going through an interesting piece of content, you might
have questions or want to delve deeper into the topic.
To facilitate meaningful discussions and encourage knowledge sharing, we've set up a dedicated QNA Forum page
related to this specific article. If you have any questions, comments, or thoughts you'd like to share, we invite
you to visit the QNA Forum.
Feel free to ask your questions or participate in ongoing discussions. Our team of experts, as well as fellow
readers, will be active on the forum to engage with you and provide insightful answers.
Remember, sharing your thoughts not only helps you gain a deeper understanding but also contributes to the
community's growth and learning. We look forward to hearing from you and fostering an enriching discussion.
Thank you for being a part of our journey!