Dr Mike: Infections and diseases you might face riding abroad


TV’s Dr Mike Leahy is an ABR who lives life on the edge. From lethal creepy crawlies to noxious bloodsucking nasties, he subjects himself to possible death-by-dangerous-insect so you don’t have to

I spent lots of my time in TV deliberately contracting diseases and being bitten by all manner of insects and bugs. I find the creatures that eat us alive or suck our blood absolutely fascinating, but they can seriously mess up your plans when biking abroad. Mosquito bites can be unbelievably uncomfortable, let alone life threatening. Malaria, which is transmitted by mosquitoes, is the world’s third biggest killer, but malaria infections are far from the only risk you might be facing when riding abroad…

Bloody Hell!

Apart from illnesses contracted from food or drink, the biggest threats you are likely to face while travelling in developing or tropical countries are diseases carried by bloodsucking invertebrates. Bear in mind that mosquito-borne diseases kill over one million people each year, 20 times more than the number killed by snakes. Unlike many holiday makers you’re not just laying on a beach trying to get a tan, so cover up and use insect repellent – but remember that ‘Deet’ might melt your bike!

Day-biting mosquitoes can be just as dangerous as those that like to suck blood in the evening. Dengue fever, for example, also known by the rather more dramatic nomenclature ‘Break Bone Disease’ is spread by Aedes aegyptii, a mosquito which is very active during daylight hours. While I was in Delhi a few weeks ago there was a Dengue outbreak which claimed a large number of victims. There was also a vicious outbreak in Rio de Janeiro when I was there last year, and in Cambodia when I was there the year before. The disease wasn’t simply following me around. The truth is that while many people haven’t heard of Dengue it is by no means a rare illness. With no vaccine, the only protection is to avoid being bitten.

Kissing bug up close!

The first time you contract the illness you will be in so much pain that you may well wish that you were dead. Symptoms include fever, headache, a characteristic skin rash, and severe muscle and joint pains. If you go on to contract a different strain of the Dengue virus at a later date you could even end up dead, because due to a quirk of our immune system you are at risk of developing the far more serious Dengue Haemorrhagic Fever. This particular strain causes severe haemorrhaging; if you really want to die bleeding from every orifice while your internal organs are effectively liquidised by this killer virus then just let those day-biting mozzies suck your blood!

Mosquitoes certainly don’t hold a monopoly when it comes to a taste for human blood, and where there are bloodsuckers there are bound to be disease outbreaks. When travelling, beware of sand flies. They are far smaller than mosquitoes, they don’t buzz when they are flying and more often than not they can squeeze through mosquito nets. The sand flies in New Zealand are a real pain. Appearing in swarms, they can make your life a misery, but thankfully they don’t carry disease. In most of South America sand flies may infect you with Leishmaniasis. It was a mild version of this disease (cutaneous Leishmaniasis) which jeopardized Ben Fogle’s trip to the North Pole. However he should think himself lucky because another South American strain called Muco-cutaneous Leishmaniasis can literally eat your face away, leaving you with no nose or soft palate, and in India yet another strain causes Kala Azar, a disease which, infects the spleen and other internal organs and is almost always fatal. If that’s not enough, the mango fly’s bite transmits worm larvae which will migrate through your body as they grow, eventually emerging out of your eye – Hammer Horror-style!

Mosquito bite

Worms transmitted by insect bite? I can almost hear the sighs of disbelief! Thankfully, the Loa worm generally causes few problems (as long as you don’t mind worms swimming around in your eyes each evening), but one mosquito-borne worm that you really don’t want to let into your vascular system is the species which causes lymphatic filariasis, more commonly known as ‘Elephantiasis’. Once the worms get into your body via a mosquito bite, they begin to hitch-hike around the two main vascular systems; the one which carries our blood and the lesser-known lymphatic system which drains body fluids and is an important part of our immune responses. Once in the lymphatic system, they breed quickly and block lymph nodes resulting in the retention of fluid in limbs and other extremities with horrifying results. If you don’t want to be dragging nuts the size of beach balls around on a skateboard for the rest of your life, then don’t allow yourself to be bitten by mosquitoes because elephantiasis is pretty much incurable.!

Fatal Reaction

On the road in Africa: beward the Tetse fly

When it comes to incurable diseases then the big hitters have to include the trypanosomes – microscopic single-celled parasites. African Trypanosomiasis (otherwise known as sleeping sickness) is found in Africa and is spread by the Tetse fly. If you’re unfortunate enough to be infected by this single-celled parasite you will suffer disruptions to your sleeping patterns, enter a coma, then perish. Around 45,000 people are known to die of this disease each year, although nobody has the money to count dead Africans effectively, and it is thought that the death toll is probably 10 times higher; the disease is pretty much 100 percent fatal. In South America a similar parasite transmits another killer disease imaginatively called American trypanosomiasis. It is transmitted by a beast called the Assassin bug, or Kissing bug. Unlike other insects it doesn’t infect you with its mouth parts. Put bluntly, as it nibbles you it also poops, and if that bug poop contains trypanosomes, and if they enter your blood stream, either via the bite wound or another scratch, you will probably end up dying prematurely. If you’re lucky your heart will simply fail, but the unfortunate may experience a failure of their gut muscles. Sufferers then slowly fill with faeces and semi-digested food before dying in agony, usually of septicaemia (blood poisoning).

Sufferers slowly fill up with faeces…

Assasin bug poo is deadly
Bed bug bites are itchy
Ticks can suck blood for days

Ticked off

If the flying bloodsuckers don’t get you, then ground-based ticks might. These talented little buggers are related to spiders and can locate you by detecting the CO2 in your breath, your body heat, or the movement of your shadow as you pass by. Once they bite many of them need to feed for hours or even days, so they cement themselves into your flesh. Not only do they spread some very nasty diseases such as Lyme disease here in the UK, Tick Borne Encephalitis in central Europe and Rocky mountain fever in the USA they can actually paralyse and kill you without the help of a microscopic pathogen. In Australia there are supposedly only three invertebrates that can kill humans: the Red Back Spider, the Funnel Web Spider and the Paralysis Tick. Unlike most tick-borne diseases, the effects of the paralysis tick’s bite (the clue’s in the name) are due to neurotoxins in the tick’s saliva. As with most Australian stories, the paralysis tick isn’t as prolific as it sounds, but people have died as a result of the bites. There are countless ‘experts’ on tick removal out there, but most of them are spouting rubbish, so read the box on tick removal. It might just save your life.

Other irritating creatures are Botflies, bed bugs and leaches. Thankfully they don’t carry deadly diseases, and there isn’t the space here to invest in creatures that don’t kill, but botflies can be bloody irritating when you find that a fleshgobbling parasitic maggot has invaded your body and is eating you alive (I know because I grew one in my leg a few years ago). Bed bugs don’t carry diseases but can cause bites that are infuriatingly itchy. Finally, leeches can be scary, gross and messy, but they don’t carry diseases. That said, once you are bitten by one you’re going to bleed for hours because of the anticoagulants in their saliva. I was unfortunate enough to have one feeding on my left testicle after filming in a lotus flower pond in Vietnam. It’s very embarrassing trying to explain away bloodstained underwear and hotel sheets, I can assure you!

There’s no point in constantly worrying or fretting about what might happen to you when travelling, but it’s worth taking the most obvious precautions as a matter of habit, just like taking the ignition keys out of your bike or locking your door on the way out of the house. This is really important when it comes to biting insects. Make sure that you have received the relevant vaccinations before you set off; cover up exposed skin and use insect repellent when necessary. Not only will you save yourself a lot of pain and discomfort, it might even save your life!

Leech and Tick removal

LeechWith any tick it is essential to remove it as quickly as possible. It usually takes a while for a body to become infected by tick-borne pathogens, and the risk of being paralysed by Australian paralysis ticks increases markedly with the length of time that the beast is sucking your blood. Stories about burning them with cigarettes or suffocating them with Vaseline are total crap because both can lead to the tick effectively regurgitating contaminated blood and saliva into your body – nice! More to the point many ticks (the hard ticks) physically can’t let go, because they need to attach to the body for some time to feed (days even), they literally cement themselves in. The only recommended way to remove a tick is by using tweezers or a special tool to grab the mouth parts very close to your skin then you should twist and pull. You should always seek medical advice some time later because the mouth parts may be left in the skin, but at least the tick, and its huge salivary glands will have been removed, together with the threat of infection by nasty tick-borne bugs. Leeches are easier to remove. Salt or a lighted cigarette will work fine, but my favourite method is simply to carry a very small lemon or lime with you. Sounds a bit inconvenient, but if you buy or find a hard un-ripe fruit it will last weeks until it is needed. To remove leeches just squeeze some juice on them; they’ll drop off immediately.

Night night, sleep tight…

However bedbug ridden or filthy a hotel is you will get a degree of protection (and comfort) by using a simple cotton sleeping bag liner that you know to be clean. You can either buy a readymade one from an outdoor shop or sew one up from an old sheet. They are light, easy to carry, and I always make sure I have one in my panniers. If you want to be really flash you can even buy liners that are impregnated with permethrin, an insecticide which is harmless to humans, but which may offer you extra protection from insect bites.

Who’s writing
Adventure motorcyclist Mike Leahy is a virologist and TV presenter who’s passionate about foreign travel. His TV shows include Bite Me for National Geographic, LabRats for BBC3, and Bodysnatchers for BBC1. Mike likes to experiment on his own body. By deliberately infecting himself with nasty diseases, being bitten by dangerous animals, and growing parasites in his insides he hopes his firsthand experience will save other adventure motorcyclists from the same fate.