You mean this awesome state where most of our children don't die before reaching adulthood?
You should really read a history book about how horrible life was before the dawn of modern industrial civilization. Our ancestors declared war on nature for a good reason and made our lives unimaginably better this way.
> Any loss of biodiversity is a tragedy.
I bet Africans disagree. Mosquitoes have killed more humans than all wars combined. Bill Gates and company are currently trying to wipe them out to save the lives of countless millions in Africa. I am pretty sure they won't miss the "biodiversity" which keeps killing them and the people they love.
By the way, the US used to have regions plagued by mosquitos and malaria too. The parasites were systematically exterminated through chemical warfare (DDT). Do you think e.g. Florida would be a better place with malaria? With hundreds of thousands of people being killed by it every year? I don't. And I am not ashamed of this "level of hubris".
> Once these genetics are lost, they are gone forever.
Not all genes are worth preserving e.g. the ones for horrible heritable diseases.
Also what you wrote is not really true, all life, all the biodiversity on earth evolved from the same archaic cells. So "gone forever" is too optimistic / pessimistic.
Rather, I think his point is that there's a hidden cost to the loss of biodiversity that ridding the world of parasites entails. Moreover, his point is that ethical analyses (such as the one you present) tend to minimize the extreme complexity of biological systems, and that therefore the conclusions of such analyses should be viewed suspiciously.
Whether that role is necessary now or not, we cannot know for certain. Of course though, we can and should limit their ability to cause “suffering.”
Imagine us killing all bees to extinction because their stings hurt, then realizing that they were necessary for many plants.
This is why you can get malaria from a mosquito but not AIDS.
Where billions are living longer, healthier, more peaceful, productive, less deceased lives than anybody though possible 100 years ago? Where we are on the tresshold of the possibility of maybe eliminating extreme poverty?
Yeah, lets try to save a few strains of DNA.
Another important aspect of parasites is that they usually only parasitise a specific species. One place where this makes a big difference is agricultural pest control. Attempts to suppress agricultural pests by introducing predators often backfire because the predator might also eat native species or itself become a pest (like the Cane Toad in Australia). Biocontrol with parasitic wasps, on the other hand, is much more targeted: http://news.nationalgeographic.com/news/2010/07/100719-paras...
Malicious agents may actually play a critical game-theoretical role in promoting in-group coöperation [1]. Sort of like how teams can be made stronger with an enemy "them" to be defeated by a now-defined "us".
(That said, I agree that any parasite that preys on humans should be eradicated.)
[1] http://deim.urv.cat/~alexandre.arenas/publicacions/pdf/joker...
> no essential ecological role
"ecological role" is a purely human concept. Nature doesn't give a shit about lions, zebras, parasites, or humans ; hence it's up to use to decide what we care about. Why should a lion be more important than a tapeworm ? Because it's less ugly ?
Mosquito larvae are aquatic, and the prey of freshwater fishes, toads, frogs, bats... they are directly or indirectly linked with almost everything around marshes and lakes: bacteria, algae, birds. We can expect a tsunami of unpredictable consequences for freshwater ecosystems and also for men. What if we wipe mosquito only to discover that they are necessary to controlling amoeba proliferation in water, for example?. We don't know.
The article has a bunch of scientists talking about recent science that questions this assumption.