Shout out to Laura, the impetus for the post.
When Laura queried me about Fifth disease, and if I had ever heard of it, I was baffled. Fifth disease? Is there a First, Second, Third, Fourth illness too?
Bad joke aside, Laura told me what she knew about the disease; it make children flush persistently, like they had been slapped. Basically, it sounded unappealing, but what sickness is?
Fifth disease is the only human parvovirus, Parvovirus B19. If you put “parvovirus” into Google, you get a lot of dog-related pages. But you can’t catch Fifth disease from your dog or cat or other animal pal. Parvoviruses are some of the teeniest viruses out there, topping out the yardstick at a whopping 20 to 25 nanometers. For my biomedical pals, they’re single stranded in the DNA department and fond of making hairpins.
The disease primarily affects children, and children are the most contagious even before they exhibit the trademark scarlet face. It sounds much like a cold; it’s spread in the same way, and other symptoms in kids can include fever and tiredness, along with a sometimes itchy rash on the body. Adults have it rough though because they will get joint pain. Usually the illness goes away on its own, lasting from about four to fourteen days. During this time, affected individuals should stay away from pregnant ladies due to possible anemia in the offspring and possible miscarriage. Some lucky people are immune or show no symptoms. Nice.
But what I really really want to know about fifth, AKA erythema infectiosum, is why is it called that?
Answer: in ye olden days, wee ones were plagued by five different skin rashes.
- Rubeola (measles)
- Varicella (chicken pox)
- Rubella (German measles)
- Roseola (controversy! also called sixth disease?)
- Parvovirus B19
Fun lab fact: the parvovirus is named B19 because of how the lab researcher labeled plates!