Ticks and the diseases they carry- the quieter pandemic.

For one thing, there are now lots more of them.

My go-to place for birdwatching is the Tavy estuary, accompanied by Zola (see pic), yet this beauty spot is now out of bounds. After finding Zola covered in several ticks after every walk there, I must save the joy of that place for mid-winter only.

After the long journey from where they land to their favoured locations on Zola’s bare skin around her eyes and mouth, they insert themselves for the long bloody feast. Thankfully she seems unbothered but they drive some dogs mad with itching. 

The Ticks clearly know what they are doing and have evolved to do it well. They travel upwards till they hit bare skin, for a hairy dog that’s around the head, though anywhere they can get to skin will do. 

They like humans too. While scratching an itch the other night I found one of the little critters happily dug in for the long haul. Nicky’s nursing skills and a Tom Tick Twister did the rest. I shall leave it to your imagination as to where it decided to stay, but its not the first time I have had a tick in my nether regions!

Their spread was recently confirmed by the experiences of moor loving friends, one of whom has to visit the doctor to have dozens of them removed after a camping trip on the moor.

Its clearly festival time for ticks!

Tick lifestyle

It all comes down to the ticks lifecycle. In a sentence this involves jumping from one animal to another, sucking blood at every turn, thus spreading infections between one host and another. 

From eggs, they hatch into larvae which latch onto small animals like mice and reptiles, feed till full, drop off, moult and become nymphs. 

These too then find another host on whom to dine till full, drop off, moult and become adults.

Adults, being larger, can crawl up grass and lie there waiting for a larger animal to brush by. They latch on, feed again, drop off, mate with any males in the area, lay about 5000 eggs and die. 

Off the cycle starts again with many many more larvae emerging to enjoy the warning weather and wait for a unwitting passer-by.

Simple, beautiful biology. Heres a picture of the egg to egg journey from the American Center of Disease Control.

This lifestyle also happens to be perfect for sharing any bacteria or viruses from the creatures on whom they dine, including us.

As with mosquitos, their mouthparts are like little hypodermic needles and so are the perfect disease generating vector. Don’t blame the ticks, all they want is lunch. The culprits are that unknown reservoir of pathogens which are a part of the natural world yet cause mayhem when they spillover into ours. 

Remind you of the origin of COVID19? Indeed.

Ticks travel well. They can hook onto migratory birds and beasts, travel on pets and traded animals and have thus spread around the world.
They are hardy too, able to survive cold and heat and even submersion in water for days and in between their feasts they use almost no energy. Like a spider that just waits for months for a meal, they can survive for very long quiet spells, just waiting.

They breed well too, each adult laying 5000 eggs many of which survive and begin their own parasitic lifestyle.

So what diseases do they bring?

Lyme disease.

While I did not have many consultations for ticks in my urban practice, the subject did come up as more people became aware that caution after a Tick bite is a good idea. 

When I was diagnosed with MS, I thought I’d better not make a fool of myself by missing Lyme disease (whose later stages have many symptoms similar to those of MS), as I had been bitten by a quite a few ticks though never with a rash or consequent fever. All tests thankfully negative. Leaning more about Lyme disease was sobering.

If you see this, see a doctor

Lyme disease is named after a town in the USA where is was first noticed as recently as 1975. It’s caused by Borrelia burgorferi, a bacterial fellow traveller with Ticks, and one of a class of bacteria called Spirochetes, so is distant cousin of Syphilis.

If a Tick is infected, and in some US states more than half of them are, then you may get infected after a Tick bite. The first stage of Lyme disease features a flu like illness and a rash which sometimes though not always, heralds the infection. This can appear from 3 days to THREE MONTHS after a tick bite. Even if you cant remember a tick bite, a rash like this means a trip to the GP.

Indeed any symptoms after a tick bite means a call to the Doctor. Further, because Ticks can bite, feed and depart without you even knowing it, a rash like this, or odd symptoms might be due to Lyme disease even if you can’t remember being bitten. If you live in an areas where Ticks are prevalent, this is important to bear in mind.

Like Syphilis, it causes a milder flu-like initial phase, then a secondary and final phase as it impacts around the body, This is thankfully rare, but shows the importance of early recognition and treatment after a Tick bite.

It is treatable with antibiotics, and the earlier the treatment the better. A vaccine has been developed to which ran into problems typical of the difficulties of modern new vaccines development. 

The vaccine, LYMErix, was withdrawn in 2002 after a class lawsuit rendered the vaccine unprofitable. The scientific consensus suggested that the vaccine was safe, with far more benefits than side effects, but the presence of some side effects and the medio-legal quagmire in the US means it is hard to see vaccine developers having another attempt. This represents the loss of a very useful method of managing Lyme’s disease.

UK Lyme disease cases 2001-17

It is now found in all US states and has travelled around the world, even to Antarctica. It now infects 300,000 people in the USA every year, is the most common vector borne disease in Europe and dare I say it, has rightly been called a pandemic.

Of course, the Tick just goes about its business of reproducing, they don’t choose which organisms join them on their journey.

So might it be interesting to look at what other diseases they bring with their dinner? I’m afraid so……

Other tick borne illnesses

• Rocky mountain fever
  

  Rash of Rocky Mountain Fever From Wikipaedia

• Queensland tick typhus
• Finlanders Island spotted fever, (Australia)
• Ehrlichiosis
• Babesiosis which comes from protozoa. 
• Powassan virus
• Crimean Congo Haemorrhagic fever
• Alpha-gal syndrome which leads to allergy and anaphylaxis to meat.

• Ghost moose with emaciated animals ill due to thousands of feeding Ticks
• Swine fever, which infects pigs
• Canine piroplasmosis, which infects dogs

For a recent review on tick borne diseases, click here, but for me, one other significant illness comes to mind:

Tick borne encephalitis

So, what to do about ticks?

Warmer shorter winters mean that the tick season is getting longer and their territory is expanding. This is a global phenomenon, with ticks and their passengers spreading, for example, from the US to Canada who have recently reported a 14 fold increase in cases of Lyme disease.

Just like COVID19, all you need is one person, or pet, or animal to travel from one area to another with tick on board too, for a tick to spread globally. And that is what has happened in the USA. 

It can reproduce without the inconvenience of mating, producing 2000 eggs containing clones of itself every six months. Thus it has rapidly spread across the USA. Watch this space!

Another example of this occurred in Mexico. In 2018 an outbreak of Rocky Mountain Fever caused by the bacteria Rickettsia Rickettsii delivered by the brown dog tick, led to 7,000 cases and hundreds of deaths. Thankfully, it can be treated with antibiotics.

Just as I end this post, a tick drops off Zola and onto the floor. I now think of biosecurity. I crush the little critter between a sheet of paper with care not to contact any of its blood. Then into the bin and from then to its ultimate incineration in Plymouth. No 5000 eggs from that one!

Perhaps I should have worn gloves and eye protection? What bugs were in its blood? Would they be able to jump from human to human? Should I self-isolate? Notify Public Health? 

Ring any bells?? 

Yet, COVID19 might well go away or become a part of life, like flu. Ticks however will not. Even if richer nations are able to treat some (though not all) of the tick borne illnesses with antibiotics or prevent them with vaccination (occasionally) we are behind the curve when it comes to rapid diagnosis and treatment or Tick borne illnesses.  

These manifold, incredible creatures are not moving into our habitat, we are moving into theirs. 

We need to adapt and adapt fast.

There is an excellent series written by Alex Bhattacharji which will take you further into the world of Ticks and many of the links in this post will also help you expand your understanding.