I already had a question about dealing with mosquitos: Really virulent mosquitos - dealing with them and their bites

But this question is about whether they really do vary in virulence and toxicity. A few people in the other question suggested I am naturally a target and react badly to bites. However:

  • I haven't in other locations had such big reactions, I get nasty lumps but not swellings several centimetres across
  • My wife gets even worse reactions, e.g. her whole calf went red and swollen from a single bite - and I currently can't clench my fist because one bite made it swell up!
  • several other people, including a gardener and a tree surgeon who both deal with such things all the time, have commented they react particularly badly when working in our garden

Interestingly this summer I am reacting differently than this time last year - bigger swellings but less itchy and no weeping wounds. This may be due to the difference between midges and mosquitos.

So - are there a large number of sub-species prevalent in the UK (NE UK specifically) or can a given population become more nasty for some reason?

  • $\begingroup$ I am glad i had stings every year aged 1-20, i dont have immunity allergy, stings are always half a lentil and itchy. I recall them being more noticeable when i was young. Different size mozzies may inject different anaesthetics and anticoagulants, but unless you get mozzy diseases in N UK, they orent toxic... you are allergic. I can get 30 stings, not very noticeable. Mozzyland people average 1 2 sting per day. $\endgroup$ Jul 12, 2018 at 5:50
  • $\begingroup$ You should have a serious read about mozzy allergies. They may contain a few bacteria bug no pathogens in the uk. Someone please write bacterial content of harmless mozzies. $\endgroup$ Jul 12, 2018 at 6:21
  • $\begingroup$ I am from Gardening Stackexchange...the thing about mosquitoes that makes them 'harmful' is not the toxicity of the stuff they have to shoot into you before they can take a sample of your blood. It is not toxic, slightly causes histamines on a different basis for different people. When they take a drink of your blood (vampire speak) they are taking lots of information from your body and then when they bite another animal they deposit a bit of you into another animal body. It is the bacteria and virus from other blood systems such as malaria, West Nile Virus that is dangerous. $\endgroup$
    – stormy
    Jul 12, 2018 at 21:31
  • $\begingroup$ Bodies don't 'build up' immunity to mosquitoes. I wish. I would be protected from mosquito bites. Not stings...Repellent is disputable, I use 'Skin so Soft' by Avon as do all the wilderness guides and back country people. Supposedly, I've read, mosquitoes leave a type of pheromone behind after drinking your blood telling other mosquitoes to stay away. I've not noticed this phenomenon and I've more than most have sat and slept and hiked in clouds of vicious mosquitoes. Mosquitoes that bite through thick jeans! I always have mosquito netting. Two pks. sewed together so two can cuddle. $\endgroup$
    – stormy
    Jul 12, 2018 at 21:37
  • $\begingroup$ By the way, whenever you get bit by something that causes major reactions please take Benadryl. Immediately. This is an antihistamine that is safe and very effective. If anything, grins, people who get lots of bites will become MORE sensitive not LESS sensitive unless they take Benadryl. You want to stop the production of histamines. They make you far more sensitive and vulnerable for the next bites. Her calf swelling up like that for a mosquito bite is not something to dismiss. There aren't virulent mosquitoes, just virulent JUICES from other bodies introduced into yours. $\endgroup$
    – stormy
    Jul 12, 2018 at 21:42

2 Answers 2


This is more a biological (immunology, serology) question, than one about gardening. It is possible that mosquitoes vary in 'toxicity', however I think the greatest part of the reaction is caused by yourself (no offense, I am prone to allergic reactions to mosquito bites too). So the chemicals that enter your body can vary per mosquito species (or even individual), which can trigger a milder or worst reaction. Just like different pathogens (bacteria, viruses) can also trigger different reactions (influenza can be innocent or deadly). But it is more likely that your own immunological 'state' is causing a worst reaction. For instance if you also have hay fever, levels of immunological molecules (etc. cytokines, chemokines) are already high in your blood and cause a larger or more intense reaction than in periods when less of these molecules are present in your blood.


Mosquito bites absolutely vary in toxicity/danger.

For a start there are multiple different types of mosquito, only some of which carry diseases like Maleria, Dengue, Zika, West Nile, Encphalitis (and different mosquitos carry different virii) Males, of-course, are non-toxic as they do not bite.

In some ways, Mosquitos are like the Flu - they mutate, and different strains have different characteristics - including when they bite - and most importantly the properties of the anticoagulant (that is what causes bites to itch)

  • $\begingroup$ Some references for a difference in anticoagulant properties would be nice. $\endgroup$
    – iayork
    Jul 12, 2018 at 12:17

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