Why can’t I take an antibiotic for my cold: A primer on viruses.

This is another article I put up on my Medium.com account.

 

As I’ve mentioned in a prior post, and is likely noted in other posts on my blog (and numerous medicine related sites), a virus is genetic material — either DNA or RNA — encapsulated in a protein coat. In some cases there is also a lipid envelope around the protein coat.

This gets to the crux of why antibiotics don’t work on viruses. Viruses need a living cell to reproduce, and does so by co opting the metabolic pathways of the host cell it invades. Normal cells use DNA to pass genetic information from one (cell) generation to the next. The DNA gets transcribed into RNA which is then taken to the cytoplasm of the cell (in eukaryotic cells) or other parts of the cell (in bacteria/non eukarotic cells), where proteins and ribosomes/ribosomal RNA read the RNA and ‘transcribe’ it into a protein.

In some cases, viruses do code for novel (relative to cells) enzymes and/or proteins. EG, reverse transcriptase in HIV viruses (HIV is a RNA based virus, but it’s genetic code is converted to DNA for replication). Other viruses replicate the RNA directly for future virus particles. However, as I note above, the vast majority of the replication is done by the cell’s own proteins.

This is why antibiotics don’t work on viruses. Bacteria have have different types of cell walls than human cells. They require chemicals that our cells just don’t use. Penicillins and cephalosporins interfere with the cell wall construction as an example. Other antibiotics target pathways our cells don’t have (eg, trimethaprim-sulfamathoxazole targets folate production in bacteria. Our cells don’t produce folate so it doesn’t affect us). There are other examples that could be used as well that utilize a chemical’s affinity for a bacterial protein/enzyme more than for the equivalent in human cells.

Having said this, there are some antiviral drugs for some (not all) viruses. These target the proteins viruses code for that are novel to the specific virus/virus family.

Now at this point, you might be thinking “well, my great aunt _namehere_ was told she had a viral pneumonia, but when she got admitted to the hospital she was given antibiotics”. In some cases, a viral infection goes through its course and the person can develop a secondary infection that’s bacterial in nature. In that case, antibiotics might be warranted. Or she was given them to prevent the superinfection/secondary infection. This is true of any viral illness, even corona viruses, rhinoviruses and covid 19.

Coronavirus biology 101

This is a post I put up in my Medium.com account.

Initially I was going to write specifically about covid19 and how to prevent getting (perhaps — or at least decreasing the chances of getting) it. I realized there are more than enough articles already about that subject and can be found on the CDC website.

Instead I decided to write more generically about Coronaviruses and doing so, hopefully address questions some people might have, and that might not be answered by posts that deal with coronovid19. First of all a virus, unlike bacteria, algae, fungi and animal cells, is just a bunch of genetic material encapsulated by protien (and in some cases, a lipid coat). They don’t have any mechanism to move, metabolize, ingest nutrients, replicate genetic material etc. Viruses are entirely dependent on infecting cells, and co-opting their metabolic pathways to reproduce. With some, there are some genes that code for things that cells — be they bacteria or eukariots — don’t have. An example would be Reverse Transcriptase in HIV viruses (Reverse Transcriptase reads RNA from the HIV genome and encodes it into DNA for use in viral replication. The virus is still dependent on the cell for the actual copying and reproduction of said genetic material and of making new viruses).

In the case of Coronaviruses, the genetic material is single stranded RNA. There are other families of RNA based viruses, such as Rhabdoviruses (EG the virus that causes rabies), Orthomyxoviruses (one such causes Measles), and others. The virus that causes HIV also uses RNA as genetic material, but by some classifications isn’t considered an RNA virus because the RNA has to be coded back into DNA for replication.

Because viruses don’t have the proteins/cell parts/etc to replicate themselves, as I note above, they’re dependent on a host cell for replication. This is why antibiotics don’t work for the common cold (or other viral illnesses. Though in some cases, such as HIV and some viruses closely related to the chicken pox virus, there are antivirals that work). As they don’t have a cell wall that’s different from our on cells’ walls, antibiotics that affect the building of the bacterial cell walls won’t work. For example, penicillin and cephalosporins interfere with an enzyme and chemical specific to what bacteria use to make cell walls. Other antibiotics interefere with enzymes and other proteins that are different enough from human cell proteins that the antibiotics don’t affect us. Others (eg, bactrim, aka trimethaprim-sulfamethoxazole) interefere with bacteria specific metabolic pathways.

Having said that, some viruses do need a particular enzyme or protein to reproduce that human (and mammalian cells in general) don’t have and do provide a target for medications. These are different than antibiotics.

As for coronaviruses, many are respiratory pathogens. In humans some coronoviruses cause the common cold. As one might expect or know, transmission can be through inhaling droplets that have active virus in them (and is why sneezing and coughing can spread the common cold, COVID-19, and so forth — the virus particles can become aerosolized). They can remain infectious on surfaces. Though the amount of time they can remain viable and therefore infectious is different for each virus and varies as well due to environmental conditions.

Anyhow, I hope this helps people understand why for viral illnesses, doctors don’t just hand out antibiotics. For COVID 19 information, use the link I have at the start of this post (it will take you to the appropriate page at the CDC).

Do Social Ties Affect Our Health? | NIH News in Health

Source:

Do social ties affect our health

This article caught my attention. In medical school we’re taught about physiology, anatomy, pathology of diseases and treatment of diseases. Yes, we do rotate through a psychiatry rotation in our third year of medical school, and in some specialties (pediatrics, for example) social aspects of health are kept in mind (some specifics probably vary from state to state, but physicians are mandated reporters for such things as child abuse and elder abue) as kids, for example, don’t raise themselves. Abuse of any kind can affect growth, development and health – especially if it involves physical abuse, starvation, etc (sexual abuse as horrific as it is, is a whole other post and not the topic of this blog post).

Some studies have indicated people who attend religious services are healthier than those who don’t. Though it has been a while since I’ve looked at the literature for this, and I think some studies make the effect to be murkier or not as solid as some might make it, these are my thoughts on it:

  1. It’s not some supernatural being, or belief in one, that makes one healthier, but the fact as someone who is involved in a community, and a purpose larger than onself.
    1. 1a) I’d add, however, that this probably includes athiests and agnostics who aren’t church/mosque/temple goers, but are involved promoting athiest ideals and in the community at large.
  2. Being part of a community might mean access to people who can help older (or otherwise impared) community members to doctors appointments, help with food, etc.
  3. Being part of a community can also help alleiviate stress levels.
  4. Married people live longer, presuming the marriage is a healthy one. Though it’s important to be part of a a community larger than 2 as well.

For more information, follow the link above.

 

The Wide-Ranging Role of the Microbiome

What goes in your stomach can influence countless disorders, from cancer to asthma. Dr David Johnson surveys the latest data underlining the ever-increasing importance of a low-fat, high-fiber diet.

Source: The Wide-Ranging Role of the Microbiome

 

Anyone who’s been reading my blog probably won’t be surprised by my linking to this article (you may have to subscribe to medscape to read the full article).

Basically, the gist is that diet effects the kinds of bacteria in one’s GI tract. The good kinds of bacteria (that promoted by a low fat, primarily plant based diet) helps reduce risk of diseases like colon cancer, breast cancer (the former by producing short chain fatty acids and the latter by altering the reabsorption of estrogen that has been chemically altered by the liver and secreted into the GI tract).

 

There’s A Difference Between The Terms Hispanic, Latino, and Spanish

There’s A Difference Between The Terms Hispanic, Latino, and Spanish

As someone who’s learned some Brazilian Portuguese (and still has a lot to learn), something like this has been on my mind for a while. One of the things that us physicians are supposed to have is cultural competence. I think that before I started learning Portuguese, when I heard the term Latino/a or Hispanic, Spanish speakers typically came to mind. Granted I realized that encompassed people from many places as cultures (a patient of Puerto Rican decent who’s family has been in the U.S. Mainland for a generation or two might not have all of the same concerns as people who came from Columbia, Peru or Mexico).

Even people who come from the same country might be very different, though more similar to each other than they are to the ‘average’ american. In this I think of people from China where there are many languages and dialects spoken. Even in the U.S., someone who grew up in New England might have a much different outlook than someone who grew up in the Mid West or South East of the U.S. They might have different dietary proclivities as well.

Does that mean it’s useless or futile to try to be culturally competent? No. But it does make it more interesting at times. I think it just means keeping an open mind and remembering people from other cultures might have different expectations of time, needs from their physicians, etc. It is also helpful to know who a patient might – or would – rely on for decisions and for help. What might be considered to be “on time” for an appointment for a physician, might not be for someone where the sense of time is more fluid.

Another reason for being culturally aware – and here I am also including having a knowledge of a country’s or ethnic groups history – is risks for certain diseases. For example, if one doesn’t know much about the colonization of Cape Verde, one might not know to test a patient for Cystic Fibrosis mutations in a couple who are concerned about genetic diseases before getting pregnant. In Jewish populations, one might think of Tay Sachs as being a “Jewish Disorder”. However the genetic disorders jewish patients who trace their ancestry to Spain prior to 1492 (Sephardim) or to the near east (E.G., Persia) actually mirrors the countries they come from (For example,they can carry mutations for certain forms of Muscular Dystrophy). Knowing this kind of history helps inform decisions about testing and treatment.

Insured Americans Up to 3 Times Likelier to Get Preventive Care: CDC: MedlinePlus

Insured Americans Up to 3 Times Likelier to Get Preventive Care: CDC: MedlinePlus.

While I don’t have any answers as to universal health care coverage, whether there should be one payer or many. However it’s nice to see something that shows a positive effect for having insurance.