Sheesh, Sab... This conclusion of yours is inaccurate, too!! [I ignored it at first - but in looking at it now...]
"...Take the Internal Combustion Engine for example: ... This invention has killed far more people than tsetse fly could ever dream of, but yet the device is manufactured and freely sold around the world. ..." Sab, post #7734, page 1
Oh, really, Sab???
Do you mean to tell me that, at a kill-rate of over 250,000 per year, and an existence that dates back over 34 MILLION years, that the tsetse flies have NOT killed as many people as automobiles, which have only been in existence for around a HUNDRED years????
From this website: http://en.wikipedia.org/wiki/Tsetse_fly
"...Tsetse have been extensively studied because of their disease transmission. These flies are multivoltine, typically producing about four generations yearly, and up to 31 generations total over their entire lifespan.[3]
... Fossilized tsetse have been recovered from the Florissant Fossil Beds in Colorado[3] showing that tsetse have allegedly existed in their modern morphological form for at least 34 million years. There are 23 species of tsetse flies. Diseases transmitted by tsetse flies kill 250,000-300,000 people per year. ..."
Sure, automobiles kill around 1.25 million per year NOW - but that is a very recent kill-rate; as one moves back in time to 50 years ago, when there were far fewer cars, the numbers drop dramatically...
On the other hand, since humans have been in Africa - and in range of the tsetse fly - for well over 100,000 years, one can see that the human death toll from tsetse-fly infection MUST be much higher than that of automobiles...
And if you'll take a look at OVERALL causes of death, as shown here at this website: http://en.wikipedia.org/wiki/List_of_causes_of_death_by_rate
Deaths per 100,000 per year
Group Cause Percent of deaths All Male Female
All Causes 100.00 916.1 954.7 877.1
A Cardiovascular diseases 29.34 268.8 259.3 278.4
B Infectious and parasitic diseases 23.04 211.3 221.7 200.4
A.1 Ischemic heart disease 12.64 115.8 121.4 110.1
C Malignant neoplasms (cancers) 12.49 114.4 126.9 101.7
A.2 Cerebrovascular disease (Stroke) 9.66 88.5 81.4 95.6
B.1 Respiratory infections 6.95 63.7 63.5 63.8
B.1.1 Lower respiratory tract infections 6.81 62.4 62.2 62.6
D Respiratory diseases 6.49 59.5 61.1 57.9
E Unintentional injuries 6.23 57.0 73.7 40.2
B.2 HIV/AIDS 4.87 44.6 46.2 43.0
D.1 Chronic obstructive pulmonary disease 4.82 44.1 45.1 43.1
- Perinatal conditions 4.32 39.6 43.7 35.4
F Digestive diseases 3.45 31.6 34.9 28.2
B.3 Diarrhea diseases 3.15 28.9 30.0 27.8
G Intentional injuries (Suicide, Violence, War, etc.) 2.84 26.0 37.0 14.9
B.4 Tuberculosis 2.75 25.2 32.9 17.3
B.5 Malaria 2.23 20.4 19.4 21.5
C.1 Lung cancers 2.18 20.0 28.4 11.4
E.1 Road traffic accidents 2.09 19.1 27.8 10.4
B.6 Childhood diseases 1.97 18.1 18.0 18.2
Look at all those causes of death that are HIGHER than automobile accidents - heart diseases, parasitic diseases - including those carried by the tsetse fly - cancers, strokes...
Heck, automobile accidents are only #19 on the list...