Rhinoviruses – Picornaviruses

00:01 Now let's look at rhinoviruses, the cause of the common cold.

00:04 And you see another beautiful model of rhinovirus right in front of you.

00:08 It looks so gorgeous, except that, as we all know, having a cold makes you miserable.

00:14 The rhinovirus is acid labile, meaning that if it is swallowed into the stomach, and it's exposed to gastric mucosa and gastric acid, then it will be inactivated, most often.

00:28 However, because it is a respiratory transmission, it most often is acquired through the nasal passages depositing into respiratory tissue in that way.

00:37 There are more than 100 serotypes of rhinovirus.

00:41 So even if you are exposed to and infected with 1 or 2 of those in a season, there are plenty more options to make you just as sick the next year.

00:49 Yay, us.

00:50 There are multiple viruses that are associated with or can cause the common cold or produce what we would think of as cold like symptoms.

00:57 The most common, of course, are the rhinoviruses accounting for 30 to 50% of The most common, of course, are the rhinoviruses accounting for 30 to 50% of the common cold and existing in nature and at least 100 serotypes, all of which could be associated with the cold.

01:08 Coronaviruses are next accounting for 10 to 15%, and especially the Ozone 43 coronavirus, which is a big player in that field.

01:17 Respiratory syncytial virus, RSV and influenza viruses.

01:21 Although we commonly associate those with other types of illnesses, 10% can also.

01:26 Common colds can be caused by these viruses, especially in younger children.

01:30 And then there's a long list of other viruses, including many adenoviruses enteroviruses, the human metahuman virus, and then even influenza viruses.

01:40 Although typically those will be associated with more systemic symptoms, such as you might see with with a lower respiratory tract infection and influenza type disease. But the flu viruses also can cause cold virus symptoms only.

01:54 But yet there's still a 20 to 30% part of the common cold, which is caused by as yet unknown or undescribed viruses.

02:02 What's been interesting during the COVID 19 pandemic is that the mitigation measures, for example, community closures, crowd avoidance, social distancing, especially mask wearing and perhaps maybe an increase in hand hygiene and other hygienic measures while those were all inserted to to try and decrease transmission of the virus coronavirus.

02:23 Two, they had the additional benefit of actually causing a marked decrease in most of the other respiratory illnesses and respiratory viruses.

02:33 However, in children, as demonstrated by multiple infectious disease submissions to the journals, rhinovirus continue to circulate.

02:42 And it's probably because it is so ubiquitous, so common and just so easily transmissible.

02:49 Transmission of cold viruses.

02:52 All of them typically occurs by three mechanisms, the most common of which is direct contact. So.

02:57 So exposing the hands through what other mechanisms, shaking hands, rubbing the nose, resting the hands on a contaminated environmental surface, handling a infected or contagious fomites such as the stethoscope, you know, you name it.

03:15 But but that step then must be followed by auto inoculation into either the nasal mucosa or some other mucosal surface, such as the eyes.

03:24 So again, hand to mucosa is the direct mechanism there.

03:29 And of course, if that is so, then the easiest and most expedient way to prevent it is hand-washing.

03:34 Hence all of the infection prevention tests.

03:36 Who who strongly support hand hygiene is the most effective method of avoiding transmission of pretty much everything, but also virus vital disinfectants can help decrease transmission, and these can be simple.

03:48 Even a less than 10% bleach solution just wiped across the countertop has decreased transmission of respiratory viruses.

03:57 The other two mechanisms also are pertinent to transmission of the cold viruses, and these are both aerosols.

04:03 So small particle droplets and then large particle droplets, the so called respiratory droplets that do require still a close contact.

04:12 The typical pathogenesis.

04:14 Primary infection occurs in the nasal mucosal, sometimes even the conjunctiva, and then we get as the virus creates its, you know, lytic effects, we get edema of the subepithelial tissues.

04:27 That then drives the onset of inflammatory mediators causing the symptoms which we know of as the common cold.

04:34 Primary infection at the same time for that 1 specific stereotype, 1 out of 100, will also drive creation of secretory immunoglobulin A, which can be protective, and it will also drive production of interferons, so pro-inflammatory cytokines, which ultimately will combine to limit that particular infection.

04:54 Now, we all know that some of us suffer worse than others with the common cold, and the thing called a "man cold," it's a thing.

05:02 Guys just suffer so much worse As we look at the clinical manifestations of the common cold, following a typical incubation period of 1 to 3 days, 24 to 72 hours, then there is onset of what we all know and love sneezing, rind, congestion, headache, sore throat, malaise, etc..

05:24 Most common cold viruses, however, are not associated with a significant elevation in temperature.

05:30 So. So fever is not necessarily a prominent part of the common cold, although low grade fever certainly can be present, the duration of the symptoms can be 3 to 10 days. The common adage is three days coming, three days with you, three days going so, so up to nine or ten days.

05:47 But some special populations, such as smokers or those with underlying chronic lung disease, can experience symptoms for as long as two weeks.

05:56 And then a persistent cough, even in those populations, could persist yet longer.

06:02 The common phrase is a cold is 3 days coming, 3 days with you, 3 days leaving.

06:07 All of those describe the entire prodrome active infection and resolution of active rhinovirus.