Looking at how diseases spread using world maps

Understanding diseases and how they spread is a hot topic these days, for obvious reasons.  Let’s take a look at the different ways in which diseases can spread and see if that helps.  In each case, before scientists understood both the disease (Lyme disease, for example, still isn’t always diagnosed correctly) and the cause of the disease, there was no way to stop or slow it or to cure or manage its effects.  That’s where we stand right now with COVID-19.  It’s a work in progress.

Lyme disease. Lyme disease is a bacterial disease carried by ticks and passed on by tick bites. It is not contagious; it does not spread from human to human. It does however affect an increasing number of people within the world tick regions, and if it is not detected early, it can be a scary, debilitating disease, even fatal. Also, these ticks are moving further north and expanding  their range due to climate change.  For example, Lyme disease has moved into New Brunswick and Nova Scotia, which does not show on this map. Beware!

Range of the lyme-carrying ticks.


Malaria. Malaria is a parasitic disease passed on through the bite of an infected Anopheles mosquito. It is not passed from human to human through close contact, hugging, kissing, etc. Because the parasite infects red blood cells of its host humans, it can be passed on through blood transfusions or sharing of needles by infected people, but this type of transmission is very rare. Watch out for mosquitos in malaria-prone parts of the world.


Measles.  Measles is a highly contagious virus that lives in the mucus of an infected person (ick) and is spread by their coughing, sneezing, and even talking. People with measles are contagious for about 8 days, 4 days before the spots appear (but you have a fever and other symptoms) and then 4 days past that. Although most people recover without incident, it can produce serious and life-threatening complications in some people.  There is a simple way to protect both yourself and the rest of your community from measles: get vaccinated. This disease was largely wiped out in most western countries because of the effective and easily available vaccine, until people decided to stop being inoculated. Brilliant.


Typhoid. Typhoid is a bacterial disease spread by contaminated food and water. In those parts of the world where it is endemic, it thrives because of poor sanitation and lack of access to clean water. In other words, it is a disease of systemic poverty. It is very rarely passed on by hugging, kissing, or close contact. Typhoid fever can last from a few weeks to being life-threatening.

Image credit: prezi.com


Flu. The flu (influenza) is caused by a virus, which can come in different variations in different years. The flu is generally spread by virus-containing droplets from the coughing and sneezing of infected people; in other words, it’s an airborne disease. We’ve all been to a doctor when we’ve been sick with the flu and been told that it’s a virus, just go home and wait it out. There aren’t medicines for cure, just for prevention.  We also all know that it’s no fun at all and we know how to take precautions. If we have the flu, stay home, at the very least to protect others from getting it. Cough into your sleeve or into a tissue. And above all, get your flu shot every year. Even if you get the flu after your shot, it will be much milder. And you will protect others. Like many other illnesses, the flu can have devastating consequences for people with underlying health issues.

Image credit: who.int


COVID-19. COVID-19, as we all know all too well, is caused by a virus, a coronavirus. Because it is just now introducing itself to the world’s human population, we don’t know as much about it as we would like. And we can only produce an effective vaccine as we learn enough about the virus. And then have tested trial vaccines. Meanwhile, we do not know for sure if people who have the virus but display no symptoms and never will can still pass along the virus. My understanding has been for several weeks that this is one of the biggest challenges: We don’t know who is carrying the virus unless they present with symptoms, but they still may be carriers. Hence the importance of closing things down and self-isolating. So I was dumbfounded last night to read an article on CNN, not FoxNews, suggesting that “infected people without symptoms might be driving the spread of coronavirus more than we realized.” Really? This is a surprise?? Had that really not been considered by many officials in the U.S., as stated?

Image credit: ECDC Europa EU, March 14, 2020

At any rate, here we are in lockdown around the world, as we try to get a handle on the latest enemy to strike (in this case a virus). This map of COVID-19 shows numbers of reported cases per population as of March 14, 2020, but as we know, it changes every day. I’m afraid we have a long way to go before it’s contained. Stay safe, everyone. Keep your social distance.  Keep washing those hands!


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12 Responses to Looking at how diseases spread using world maps

  1. Dr B says:

    A very interesting comparison. The knock on effects of this outbreak are startling……. stock market collapses, lockdowns, supermarket shelves empty, grocery deliveries full booked/unavailable weeks into the future, self isolation about to be implemented for 70+ across the UK. A lot of people are about to experience what their grandparents experienced in WW2 in the UK.


    • Jane Fritz says:

      Thanks, Dr. B. Well, around the world we’re all learning a bit about privation and pulling together, but we’re not sending our young men (and now young women) off with guns to shoot each other or bombing each other’s homes. I’m pretty sure the Syrians, Yemenis, and some others who find themselves caught up in war right now would choose self-isolation without enough t.p.! Still, this is unique in our lifetimes. In other countries we’re already in self-isolation.

      Liked by 1 person

  2. dfolstad58 says:

    I liked this post as it well organized and illustrated. I would like to see one about the benefits of vaccination as many people don’t, mainly they don’t understand why it’s important. At least I hope that’s the reason. It leads into the fact that hopefully in the future there will be more vaccines but they are worthless if people don’t get them. While saying that I also believe that it saves money for the vaccines to provided for free. When people are sick, the losses to an economy is a huge multiplier and hopefully the decision makers understand that fact.


    • Jane Fritz says:

      What you’re saying is so important, David. Good suggestion. Maybe I’ll see what I can dig up specifically re vaccination vs no vaccination for next Monday. One thing about self-isolating, there’s lots more time for blogging!

      Liked by 1 person

  3. “Had that really not been considered by many officials in the U.S.?” Sigh. Will “I’m sorry?” suffice? I feel like saying that to every person outside of the U.S. for three years now. – Marty

    Liked by 1 person

    • Jane Fritz says:

      You have my full sympathies, Marty. Yes, he has caused damage to the entire world, but even more to his own country. For all of you who feel that way too – the majority of Americans – you don’t have the option of just leaving for another country. Your only option for yourselves is to campaign for your chosen candidates, and vote. Vote strategically. Help get out the vote. And keep blogging! 😏

      Liked by 1 person

  4. Roy McCarthy says:

    Good to read a bit of informed information amongst the loud hum of chatter, comment and opinion.


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