The Most Dangerous Organisms In North America

This article, authored by Jerry Cates, was first published on 6 April 2022, and last revised on 8 October 2022© Bugsinthenews Vol. 24:04(01).

This article — like all the others that have been posted here — is a work in progress. It is also one of those “mind-bending,” or even “mind-stretching” papers that, if properly presented, should force you to think out of the box, and dig into important questions you may not often think about. The subject matter is challenging, for the author as much as the reader. As such, it is subject to constant revision and updating. Every article of this kind is a learning experience. Each develops and matures over time as more research is carried out. And, as much as possible, each incorporates all the learning that takes place — once fully vetted — as part of the revisioning process. Come back often, and you will see what that means.

Before proceeding further, it will help to define a few terms. All “living” organisms found on planet earth are presently considered to fall within three taxonomical domains, the Archaea, the Bacteria, and the Eukarya. This three-domain classification of life, proposed by Carl Woese and others in 1990,  excludes non-cellular “non-life-forms” like prions (misfolded proteins, bereft of DNA or RNA, which are capable of transmitting their misfolded shapes onto normally-folded variants of the same protein), or viruses, virusoids and viroids (all consisting of various forms of DNA or RNA, but which cannot replicate except within living cells).

Some scientists argue that Woese’s classification should be expanded. The term “organism” has as one of its main definitions “an individual form of life,” and by that definition Woese’s classification is complete. Another definition of organism is “A system regarded as analogous in its structure or functions to a living body.” In other words, it isn’t necessary to be “alive,” as long as functionality and structure can be considered as analogs — roughly or otherwise — of living bodies. We could easily stretch that definition to include the ability to assume a condition of “living” under certain conditions.

Although prions and viruses, and associated molecular structures like virusoids and viroids, are not themselves “alive,” or complex enough on their own to meet that second definition, they still “come to life” with dramatic consequences once introduced into living cells.  For this reason alone, prions, viruses, virusoids, and viroids are included in the list of organisms to be evaluated here. Thus, they will be considered along with single cell prokaryotes lacking nuclei that fall into the Archaea domain, single cell nucleated procaryotes that comprise the Bacteria domain, and multi-celled eucaryotes like plants and animals that compose the Eukarya domain.

So, across that entire spectrum, we now ask this question:Which would you place at the top of the list of those that pose the gravest dangers to human life and well-being?

That’s an interesting question. It becomes even more interesting when we discover that, no matter who you ask, the answers you get are almost never the same. Often they aren’t even in the same ballpark. Most people don’t think of organisms the way we do here, by including all those mentioned in the list we just described. One needs at least some involvement in, or education or training relevant to the biological or medical fields to be inclined to do so. Yet, unless we cover that entire spectrum, it would be impossible to prioritize the dangers that exist in our environment in any sensible way.

If at this point you are apt to say, “Fine, that’s for the doctors and environmentalists to decide… I have better things to do,” you’re probably typical. I suppose it’s ok to be typical… by definition most people are, and being atypical isn’t considered cool… But thinking individuals rise above the norm. They know that by doing so they are able to accomplish more and improve their health and welfare and that of their loved ones far beyond that experienced by the average, i.e., typical, human.

I challenge you: dare to be atypical. It’s worth the effort. This article was written precisely to bring that point home.

Each of us has to make important decisions — every day — based on how we prioritize the gravest dangers we face as the day progresses. We strive to protect ourselves and our loved ones from the dangers that are most likely to impinge on our and their lives. How well we do that is based on the efficacy of our decision-making process.

Is yours up to speed? Ask yourself that question and be honest with your answer. How efficiently (i.e., intelligently) we make decisions affects our lives in myriad ways. That process needs to be in tip-top shape. Our personal health and welfare, and that of our loved ones — those impacted by the decisions we make — depend on it.

Practically every step we take involves decisions. If we counted all the decisions we make throughout the day the number would likely surprise us. If we categorize those decisions by their relative importance, we might be even more surprised, particularly in terms of how we treat those at the top of our priority list and those at the bottom. It seems, today, that most folks concentrate on those priorities that give them pleasure, and give short shrift to those that pose danger to life and limb. That’s not a good approach to life. Concentrating first on the the dangers we face is a key both to welfare and longevity.

What About Your Danger-Priority List?

How accurate is your priority list? The one delineating the dangerous organisms you should avoid, day after day, as you go through life?

If you are typical, it isn’t accurate at all. Honestly, though, even if you are way beyond typical, it may not be much better.

That’s a bold statement, but it’s easy to prove. Most of the highly educated people I discuss this with, including those holding PhD’s in chemistry, biology, epidemiology, and even those with MD’s, DO’s, or ND’s after their names who are actively practicing within the medical field, think they have a good idea what the most dangerous organisms are that they face every day. But when pressed for specific examples, the forthcoming responses span a long list of possibilities that are not at all similar. I’d expect to witness some kind of consensus from such a group of individuals, but it isn’t there. Remember, we need that list of priorities imprinted on our brains so we can use it every day, and if it’s absent, or if it is present but fails to represent the real world, we’re not going to make good decisions.

Stop for a moment and make your own private danger-priority list on a scrap of paper. Nobody is watching, and nobody will grade you. Make the list, fold it up, then hide it in your purse or billfold, while we check out what other sources of information on this question have to say. Later, you can look it over again, privately, to see if it and what this article says are even remotely congruent…

Google’s “Helping” Hand…

Let’s go to Google first. Isn’t that where we usually go these days for answers to vexing questions? Hey, if Google can’t help us, who can?

That was a flippant question, I admit, but in truth most of us do that every day. Google is the “go-to” source of information on just about everything under the sun for 88% of those who search the web. Described as an American multinational company that focuses on artificial intelligence, Google began as an unbiased method for “surfing the web,” one that appeared at the onset as a truly objective means of leading us to answers for every question we could imagine. For several years, it served in that role in a stellar manner. Had it remained so, the Internet would be a much safer, and better, place today than the virtual minefield it has become. Over time — following the path we’ve all grown to recognize for its devolution from remarkably wonderful to horribly bad — it slowly morphed to take advantage of its growing popularity, straying from objectivity as it developed into a behemoth advertising and money-making machine.

Regardless of its merits and demerits, we seem to be stuck with it. Today Google provides what amounts to the primary means people use for searching the Internet, having nearly vanquished all its competition. Yes, Yahoo still exists, and Bing continues to grow in popularity. DuckDuckGo and a small list of similar anonymous search portals are available, too, enabling you to search the web without being tracked, but they utilize other search engines — like Google — to conduct their searches, so the demerits of those engines inevitably taint their search results.

Ostensibly, in something even fractionally approaching a perfect world, Google would have vanquished all its competitors by being better than they were. In a truly perfect world that would likely mean that it serves the user’s purposes better than all the rest. That should translate to a functionality that requires it to interpret your expressed search criteria — in the form of a set of key words — into a search of the Internet that resolves into links containing information directly related to those specific keys. Then, from those links, we ought to get some idea what the rest of the world thinks those words mean.

Let’s do a little test to see how well that works. I’m doing that just now, using Google by searching on “The most dangerous organism in North America.

The first link that Google gives me is an article by Sage Marshall, writing in Field & Stream magazine and published  on 29 September 2021. His title? “The 5 Deadliest Animals in North America — And the 5 States With the Most Fatal Attacks.” Each year, he tells us, people lose their lives as a result of animal attacks. He then lists the 5 deadliest animals in North America to be 1. Brown Bears, 2. Sharks tied with 3. Snakes, followed by 4. Black Bears, and finally 5. Alligators. He then goes on to list the states with the most fatal animal attacks.

Mr. Marshall graduated from Wesleyan University in 2019, with a major in English concentrated in creative writing and a minor in history. His lists were excerpted from a study done for Outforia, a Norwegian media company focused on the outdoors, looking into the number of fatal animal attacks on humans, in North America, between 1970 and 2019.

Let’s quickly evaluate the information value of this list. Google evidently uses an algorithm that equates the broad term “organism” with the much narrower term “animal,” and the somewhat expansive term “dangerous” with the more restrictive “deadly.” This first link is telling me — through the writings of a relatively inexperienced journalist (that’s not a slight, Mr. Marshall, I envy your youth) — that of all the sources of information on the Internet, Sage Marshall’s list provides at least one contender (but one Google elevates to the top) for the very best definitions of “The most dangerous organism in North America.”

Sage didn’t write this specifically to meet my search criteria. He had a narrow focus, tailored to the needs and interests of those who hunt and fish. That audience wants to know what he had to tell them, and he did a masterful job meeting their needs. I suppose his career as a journalist gets a boost from Google’s choice, so… good for him.

But bad for Google. As today’s most-used search engine, there seems to be no good reason, but probably a few bad ones, for choosing Sage’s article to be first on the list of articles supposedly conforming to my search criteria. There must be numerous articles on the Internet, written by world-renowned scientists on this subject, that Google could have placed first in the list, but Sage’s was picked instead. I still remember when Google had competition from a host of very good search engines. In those days, search criteria mattered. Not today.

Critiquing Sage’s List…

What’s so bad about Sage’s list? Well, to begin with, for the vast majority of us Americans the likelihood we will run into brown bears, sharks, snakes, black bears or alligators today is practically nil. Here in Texas rattlesnakes might be an appropriate item on our list, but even that is nowhere near the top. I initiated this search in hopes of learning something I didn’t already know, yet nothing in Sage’s list met that criteria. If I happen to see a brown bear today, or a shark, a venomous snake, a black bear or an alligator, well, gosh, I already know to steer clear of it. I think I even knew that by the youthful age of… 2? Yes, maybe even earlier. Avoiding contact with such animals is practically a knee-jerk reaction, one imprinted on the human brain early on, so Sage’s list doesn’t appear capable of improving anyone’s  existing decision-making process one bit.

To be fair, I didn’t make it clear to Google that I didn’t need a list of “obvious” dangerous organisms, just the most dangerous ones. On the other hand, nothing in my search criteria indicated my focus was on animals, or that — within that focus — I was concerned about animals I might come across while hunting or fishing.

To be extra fair, let’s continue on, still with Google’s… ahem, “assistance,” and see what else this search brought to the fore. Maybe Google burped on this first link, and the next will be more on point…

The second link in Google’s list is an article in Newsweek, by Alexandra Schonfeld, published on 10/31/21. She reported on “… the States With the Most Fatal Animal Attacks.” Alexandra recently graduated from Elon University with a degree in journalism, and references the same Outforia study as Mr. Marshall. The time frame involved in that study was 1999 through 2019, a total of 20 years. Texas is the first state on the list (520 deaths, averaging 26 annually over the 20 year period) followed by California (299), Florida (247), North Carolina (180), Tennessee (170), Georgia tied with Ohio (both 161), and finally, Pennsylvania (148). These deaths, by the way, resulted from interactions with the dangerous animals mentioned in Mr. Marshall’s list.

Another junior journalist, fresh out of college, Alexandra is enthusiastic, and exhibits great writing skills and lots of potential that will serve her well in the future (again — I envy her youth…). She was writing in a weekly news periodical for John Q. Public, and she nailed it for that group. But to what purpose? Sensationalism, evidently, and little more. Consider the statistics. Texas, at the top of the list, suffered 26 annual fatalities from all those animal attacks over a 20 year period. I thought more Texans died from infected hangnails than that… That was a joke, but you get my point. Making a priority list of organisms to avoid every day, using Sage’s and Alexandra’s articles, would not be — for most of us — very useful. Still, to be as fair as possible, let’s give Google one more try…

The third link is an article in Reason, written by Ronald Bailey published on 11/21/2001. Born in 1953, Mr. Bailey is eleven years younger than I. He attended the University of Virginia earning a B.A. in philosophy and economics in 1976. His journalism career focuses on scientific topics, garnering him a ton of impressive awards. Having lectured at Harvard, Rutgers, McGill and a long list of other universities and institutes, his credentials seem impeccable. And he focuses on biology, too, another indicator he should know a good priority from a bad one.

Well, with that background Bailey qualifies as a trusted writer on science-based issues. I can’t envy his youth since, like me, he’s not there anymore. Hopefully, he used his accumulated wisdom to make sense out of questions like the one before us.

So what does Mr. Bailey think merits the title of “The most dangerous organism in North America“?

Bambi, that’s who

Mr. Bailey points out that there are about 1.5 million deer/vehicle collisions annually in the United States. Those collisions, he informs us, cause around 29,000 human injuries. Resulting insurance claims exceed $1 billion. Not only that, but the Bambis responsible for this carnage are infested with biting ticks infected with Lyme disease, and spread their infections to around 13,000 humans each year. But wait, there’s more… Bambi, he rightly notes, also causes damage to agriculture, timber and landscaping, by munching on crops in the field, damaging trees in our forests, and laying waste to shrubs, flowers, and bushes at our homes and businesses. Those annual economic losses alone total $1.2 billion.

Really… Bambi? Deer/vehicle collisions? This defines the most dangerous organism in North America?

Again, I intend no disrespect to Mr. Bailey. His well-written article was published in Reason. It’s a publication distributed by a reputable think tank, the Reason Foundation, a non-profit tax-exempt organization based in Los Angeles, California. Established in 1978, the Foundation’s mission is to advance a free society by developing, applying, and promoting libertarian principles, including individual liberty, free markets, and the rule of law. Drew Carey, one of Reason’s key people, hosts the Reason TV video website. All of that is laudable, on many different levels.

Still, Mr. Bailey’s article didn’t tell me much of value on the subject of “The most dangerous organism in North America.” His exposition on the dangers of Lyme disease might have come close, though. Lyme disease is a serious issue, and although Mr. Bailey’s article doesn’t make it sound nearly as bad as it actually is, for certain Americans it is or should be close to the top of the dangerous organisms they need to avoid.

Still, one doesn’t do that directly. You can’t just “decide” to avoid the bacteria causing Lyme. Instead, you have to steer clear of its vector, the tick in the genus Ixodes that brings the bacteria to you. Lyme disease is mostly transmitted to humans by the bacterium Borrelia burgdorferi, and sometimes by Borrelia mayonii, through the bite of infected blacklegged ticks. Some 30,000 cases of Lyme disease are reported to the CDC every year in the United States, far more than the 13,000 Mr. Baily’s Bambi’s dish out. Deer are not the only, and may not even be the most effective, carriers of infected blacklegged ticks. But even the number of Lyme cases reported to CDC understates the total number of infections that take place annually. Research by the CDC suggests up to 476,000 Americans get Lyme disease every year, most of which are never diagnosed, much less reported.

So, why aren’t Lyme disease or the blacklegged tick (Ixodes scapularis) or its Pacific-coast species, the western blacklegged tick (Ixodes pacificus) at the very top of our list of most dangerous organisms in North America? Good question. Let’s see if we can make sense of this.

Click on the link for Ixodes scapularis, above, to see a map showing where I. scapularis is found. If you are in one of the states in the Northeast, mid-Atlantic, or upper Midwest regions of the United States, your chances of getting Lyme disease from a tick bite go up considerably. In Texas, by comparison, your chances drop dramatically. West of the Rockies — half the land mass of the lower 48 states — the bottom falls out, as the likelihood of encountering an infected blacklegged tick drops to nearly zero.

More to the point, even if you contract the disease the likelihood you will die from it is very, very low. Furthermore, if diagnosed early Lyme disease is usually cured with a round of antibiotics taken over a 10-14 day period. Some Lyme infections do result in Post-Treatment Lyme Disease Syndrome (PTLDS), and that can last six months or more, but even PTLDS improves over time, as a rule.

Blacklegged ticks are carried by wild animals, so if you are in an area where these ticks and the wild animals carrying them are common, you do need to take steps to prevent tick bites. Fortunately, that’s easily done, simply by using one of the cheap, over-the-counter mosquito, chigger, and tick repellents available at the corner drug store. If you are wise enough to use one of those repellents every time you go where ticks may be found, you probably won’t get bitten, period. In other words, make part of your decision making process the appropriate application of a good, over-the-counter biting insect repellent, and thereby obliterate your risk of getting Lyme disease.

In summary, Lyme disease is a serious concern, in some places, but not everywhere, and even where it is a concern it is almost never fatal, is usually cured quickly, and rarely has lingering aftereffects. So, while Lyme disease definitely merits a place on our list, that place is nowhere near the top.

Whew! Well, so far we’re not getting very far… We’ve been more than fair to Google, but the search results are burgeoning and, to save some time, I dug a little deeper into the Google search results on my own. The next 25 links Google provides were no better than the ones already discussed. Conclusion? This approach just isn’t going to cut it…

Will Siri Help?

Out of desperation, I picked up my iPhone and asked Siri exactly the same question I’d earlier put to Google. Maybe Apple will do what Google cannot. The reply? A list of Internet links apparently provided from an Internet search, but not the same set of links I got from Google. Maybe Apple uses a demonstrably more objective search algorithm? Maybe?

The topmost link Siri provided took me to an article in USA Today, written by a young reporter named Jordan Mendoza. His source? The same study done for Outforia cited by Sage Marshall and Alexandra Schonfeld.


Thanks, but no thanks, Siri…

Time to Go to the Experts…

Well, since Google and Siri were a bust, let’s take our question to the real experts. I had the fortuitous opportunity to do that right away. The 2022 Texas A&M University’s Urban Entomology workshop, in College Station, Texas, started on 5 April and concluded two days later. Presentations at the workshop were provided by some of the best entomologists in the world, literally.

One lecturer, a PhD entomologist whose post-doctoral focus is in the field of vector control, posted a slide titled “The World’s Deadliest Animals.” Now, I thought, we’re really getting somewhere…

First on the slide’s list — purporting to be the deadliest of all — was mosquitoes, which were said to cause 725,000 human deaths annually. Wow! Sage’s list didn’t say anything at all about mosquitoes… Next came humans themselves, killing over 475,000 of their fellows in an average year. Again, Sage’s list left humans off, too, though to be honest having humans on the list doesn’t help much. How do you avoid contact with humans, especially those most likely to commit homicide? The answer is way more complicated than can be addressed here, so — reluctantly — we’ll pass it by. Third was snakes (50,000) followed by dogs (25,000), then Tsetse flies tied with Assassin bugs and freshwater snails (each 10,000), Ascaris roundworms (2,500), Tapeworms (2,000), Crocodiles (1,000), Hippopotamuses (500), Elephants tied with Lions (100 each), and finally Wolves tied with Sharks (10 each).

Meaty, thought-provoking statistics! The audience, myself included, loved it. You probably realize that tsetse flies aren’t found in North America, and crocodiles, hippopotamuses, elephants and lions aren’t much of a problem here unless you work in a zoo. Many of my friends do work in zoos, and have to deal with such animals, but they’re uncommon people, with uncommon occupations. Of all the items on the slide, mosquitoes seemed the most relevant to this discussion, though snakes, dogs, assassin bugs, freshwater snails, ascaris roundworms and tapeworms merit consideration, too.

The slide did not mention a source, so I queried the Internet to find out where that information came from (using Google, of course). After scrolling through a bunch of posted articles the exact slide came up (Note: it’s dated 2014, and could change at any moment, so if you click on the link and find it broken, don’t be surprised).

That slide was published by, a statistical service hosted by the University of Southern California. Statista claims to be

… one of the first statistic portals in the world to integrate data on over 80.000 topics from over 18.000 sources onto a single professional platform and providing companies, business customers, research institutions, and the academic community with direct access to quantitative data on media, business, finance, politics, and a wide variety of other areas of interest or markets.”

Holy Smokes. We’ve struck the Mother Lode!

Bill Gates & The Computer Revolution… pulls information from all over the world. It cited its source for the information on the slide in question as That’s a blog hosted by William Henry Gates III. You may know him as THE Bill Gates, of MicroSoft fame. He’s a computer software genius, and doesn’t claim to be a biologist… Still, he’s one of the richest people on earth. These days he’s said to be engrossed in solving earth’s most serious environmental challenges. As a result he likely has more than a few genuine biologists at his beck and call.

Though 13 years younger than I, it happens that Gates and I became computer nerds at about the exact same time. I was 27 in 1969 when I wrote my first software program, a mathematical simulation coded in Fortran on a 5-year-old Univac 1108. Gates, then only 14, wrote his first piece of software that same year, coded in BASIC using a Teletype ASR 33 connected to a GE computer. He programmed the game of tic-tac-toe so players could compete with the computer itself.

Digital computers had been invented in 1950, only 19 years earlier. Programming them was still a novelty in 1969. Earlier, when I worked as an analyst at Rome Air Development Center, all the complicated calculations I performed had to be done by hand, aided by a heavy and very clunky mechanical desktop calculator manufactured by the Frieden Corporation. In 1969, recently employed by Texas Instruments Inc., I had immediate access not only to the Univac 1108 but to an IBM 360 whose impressive CPU consoles, card readers, magnetic tape and memory disk machines filled  a huge air-conditioned room large enough to house an automobile dealership.

My focus was on solving problems for TI’s Department Of Defense clients. It was tedious work, and kept me busy day and night. Gates, a freshman in high school, looked past the tedium and saw the computer’s potential for everyday use by everybody.

Urban Entomology and Mosquito Control…

Anyway, putting the past behind and scrolling forward to the April 2022 workshop at Texas A&M, I listened attentively to the PhD entomologist who was presenting a slide whose content was published on Bill Gates’ blog. I felt a genuine connection here. The presenter, an obviously intelligent young lady with excellent speaking skills, was wowing us with her knowledge of the dangers posed by mosquitoes in North America in general, and Texas in particular.

Her use of Gates’ slide emphasized an important point, that mosquitoes need to be controlled as a means of protecting human health. She did a great job of updating those in attendance on the latest diseases mosquitoes transmit. Of all the many presentations I’ve attended on that subject, hers was as good as or better than all the rest, hands down. When she was finished I and my colleagues felt a renewed respect for the remarkable importance of controlling mosquitoes throughout Texas.

Her message seemed to make sense to everybody in attendance, me included. But I had some concerns the moment I scanned that slide. Since then, I’ve delved into those concerns more deeply. That slide and its content merit thoughtful examination, as much for what it didn’t say as for what it did.

Mosquitoes and Human Epidemiology…

Mosquitoes were, indeed, likely responsible for at least 725,000 human deaths in the year 2014, worldwide. Other sources even suggest the number of mosquito-related deaths for that year was higher, so the slide might have even understated the magnitude of the threat mosquitoes represent. But… are mosquitoes really the most dangerous animals in the world, either then, in 2014, or especially now, in 2022?

More to the point, though, do mosquitoes constitute the most dangerous organism in North America, particularly that part making up the lower 48 U.S. states? After all, that’s where those attending the 2022 TAMU Urban Entomology workshop ply their trades as pest management professionals.

Animals that pose significant dangers to humans on one continent often pose less of a threat elsewhere. We don’t have wild lions and hippopotamuses roaming the greenbelts of North America. Mosquitoes and the diseases they spread provide another, similar example, though it is doubtful most Americans realize it. Everything we read about mosquitoes demonizes them, the way this slide did. Granted, they probably deserve it. But are they as bad, here in North America, as we are led to believe?

Let’s consider a few facts that seem to suggest otherwise.

Worldwide, about 3,500 species of mosquitoes are recognized. In North America that number is around 200. Of those, only twelve are capable of spreading mosquito-borne diseases. While in tropical Africa and Central America mosquitoes are present — biting and spreading disease — all year round, in America north of Mexico they’re present only 4-6 months out of the year.

90% of the deaths that occur from mosquito-borne diseases occur on the African continent. The majority of the rest occur in tropical Asia, India, and the Indian Ocean. Still, Americans do become infected with mosquito-borne diseases like Malaria, West Nile, Zika, Dengue, and Chikungunya. How many of those cases occur each year? How many then result in death or permanent injury? Finally, how many were transmitted by local, vs. out of country mosquitoes? Americans travel abroad, a lot… when they return from visiting places where mosquitoes are prevalent, do they sometimes get infected abroad and then bring those diseases back with them?

Let’s have a look at each of these questions.

MALARIA: According to the Centers for Disease Control and Prevention (CDC), about 2,000 cases of malaria diagnoses are made in the United States annually.

Most malaria cases in the United States involve travelers returning from, and immigrants arriving from malaria-ridden countries, primarily sub-Saharan Africa and South Asia. Rarely is malaria locally transmitted anywhere in the U.S.

WEST NILE VIRUS: The CDC tells us that the leading cause of mosquito-borne disease in the U.S. is West Nile virus (WNV).

Most infected people are asymptomatic but about 20% develop fevers and exhibit other symptoms. About one in 150 infections produces a serious, or even a fatal illness. 

In 2020, an estimated 66 deaths were recorded in the lower 48 U.S. states from infections with West Nile virus; the majority occurred in California (235 cases, 11 deaths) and Texas (122 cases, 26 deaths).

The U.S. WNV death toll increased to 191 in 2021; the majority occurred in Arizona (1,645 cases, 112 deaths), followed by Colorado (174 cases, 10 deaths), California (115 cases, 11 deaths), Nebraska (107 cases, 8 deaths), and Texas (77 cases, 7 deaths). 

ZIKA: Prior to 2014 only a few cases of Zika virus were recorded in the U.S., and all that were recorded were travel-related.

In 2015-16, coinciding with large outbreaks of Zika in South America, travel-related cases began to be recorded in U.S. states. Widespread transmission of the disease also took place in Puerto Rico and the U.S. Virgin Islands. At the same time, limited local transmission of the disease took place in Florida and Texas.

In 2017, the number of Zika cases in the United States declined. No reports of Zika cases transmitted by mosquitoes have been reported in the continental United States since 2018, and — since 2019 — no mosquito-borne cases have been reported in any of the U.S. territories, though 57 non-mosquito-borne cases were reported in that year, presumably resulting from sexual or laboratory transmission.

DENGUE: Between 2010 and 2021, as many as 9,193 cases of Dengue were recorded in the U.S.

Of those, 8,706 (95%) were acquired while traveling in other countries, 487 were locally transmitted, and 4 were the result of accidental laboratory transmissions. The death toll for this period is not available.

The majority of the locally transmitted cases occurred in Hawaii (250), and Florida (193). 39 occurred in Texas, 2 in North Carolina (both from laboratory accidents), 1 occurred in New York, and 1 each occurred in Washington DC and West Virginia (both accidental laboratory transmissions).

CHIKUNGUNYA: According to the CDC, chikungunya virus disease has rarely affected U.S. travelers.

Between 2006 and 2013 about 28 people annually (ranging from 5-65 each year), all of whom had traveled to or returned from Asia, Africa, or the Indian Ocean, tested positive for recent chikungunya virus infection.

In the latter months of 2013, a single case of local transmission was reported in the Caribbean, then — in 2014 — a total of 2,799 cases were reported in travelers returning from affected parts of the Caribbean, and 12 cases of local transmission was observed in Florida, Texas, Puerto Rico, and the U.S. Virgin Islands.

In 2015 a total of 895 cases of travel-associated chikungunya virus infection were observed in the U.S., along with a single case of local transmission. Since then, no cases of local transmission have been observed, and the number of travel-associated cases has declined steadily, to the point that in 2020 only 33 such cases were reported.

The Problem with Agenda-Driven Statistics…

From CDC’s files on mosquito-borne diseases in the United States, it seems that, although mosquitoes pose a serious threat to certain parts of the world, the risks they pose to persons living in the continental United States are relatively low. The West Nile virus is the greatest threat we face from mosquitos, but even that caused less than 200 deaths, nationwide, in 2021.

Every death matters, to be sure, so the threat from West Nile virus should not be trivialized. At the same time it should be mentioned that mosquito bites can generally be avoided through the use of inexpensive, over-the-counter mosquito repellents. The fact that mosquitos are seasonal, only pose a threat for 4-6 months out of the year, and their breeding habits enable us to reduce their numbers through smart stewardship of the environment, makes it even easier — for most people — to avoid their bites.

Of course, there’s something else — besides death totals — to consider, too.

Death is not the only way to measure danger. Another factor, misery, may matter as much as the D word. Mosquitoes can make us miserable, but as already mentioned we can avoid those miseries rather easily. What about animals that can cause death, but that also cause human misery short of, or leading up to, death? And what about the indirect causes of misery and death emanating from the myriad ancillary behaviors common to those organisms? Most important, what about animals that are not so easily avoided?

Achieving a reasonable perspective that considers all these points isn’t easy. That probably best explains why they can be — and often are — answered with simple examples like the ones in the Gatesnotes slide. Still, doing so risks missing important marks that should figure in shaping opinion. After all, it is opinion, particularly that which prevails within a given time frame, that largely determines where scarce resources in time, labor, and money are allocated to craft and implement solutions to them. But gaining a reasonable perspective is crucial. Opinions based on good logic are more likely to direct those allocations rationally.

I admit to not having satisfactory answers at present. We should not shrink from seeking those answers, though, and we should conduct our search for those answers with vigor. If we do, we’ll eventually get there. Unfortunately, if this exercise tells us anything so far, it is that nobody seems close to doing that at the moment.

Commensal Rodents, Ignored, but Definitely in the Running…

Mosquitoes and the diseases they spread are important, but they are not the only, and possibly are not the worst threats to human life and well-being in North America.

Commensal rodents — comprised of only three species of rats and mice — are just as likely contenders for the title of the most dangerous organisms on earth as any. They and the diseases they carry and spread to humans are found practically everywhere humans exist, worldwide. Yet they were not even listed in the slide published by Gatesnotes. Nor were they mentioned in the articles written by Sage Marshall, Alexandra Schonfeld, Ronald Bailey, or Jordan Mendoza. It is reasonable to ask — rhetorically, at least — why they were left off those lists.

For reasons not immediately apparent, it is not fashionable to champion projects focused on control of commensal rodents: I’ve searched the Internet for all the health and welfare projects funded by the Gates Foundation, for example, and not one mentioned rodent control. Why not? Maybe that’s the real question we should be asking. It isn’t because we don’t know how dangerous those infestations of rats and mice are…

Rats & Mice, Unrivaled Disease Super-Spreaders…

Three species of rats and mice — widely considered the commensal triumvirate — rival every other animal on earth as super-spreaders of disease. History makes that plain. Together they orchestrated the greatest pandemics of all time, spreading the plague known as the Black Death that killed over 50 million people. Those deaths took place in 14th century Europe. Human populations were much smaller then, so each death had a proportionally greater impact than now.

Even today the plague continues to infect over 600 people every year. But that’s not all… It is estimated that, each year in the U.S. alone, as many as 50,000 people are bitten by rats. Rats carry from 55-63 known diseases (and probably a much longer list of diseases we don’t yet know about), so their bites can lead to more serious problems. Most of those bitten are children, i.e., that subset of humanity most vulnerable to disease. Just in the past century alone, it is said that more than 10 million people have died, worldwide, from rodent-borne diseases, but — as with mosquitoes — the greatest consequence in North America isn’t death so much as misery. Good health, sanitation, and a protected food supply see to that.

Speaking of food, mosquitoes have little or no impact on our U.S. food supply, but commensal rodents contaminate, render inedible, and consume a large fraction of the farmed and stored nutriment intended for human use. They are as destructive in this manner in North America as anywhere. By doing so they deprive us of one-fifth to one-third of the world’s food supply, year after year after year. Maybe few Americans starve as a result, but starvation still happens in America, and rats and mice are part if not most of the cause. In other parts of the world, how many millions of humans starve to death, under miserable — even horrible — conditions, because the food they need to stay alive is damaged, destroyed or eaten by rats and mice? By that one measure alone, the argument could easily be made that commensal rodents are at, or certainly near, the top of the list of the world’s most dangerous animals.

But, while wolves and sharks — both cited as causing, on average, around 10 deaths annually — get star listing, commensal rodents don’t even merit an honorable mention in the Gatesnotes slide. That’s more than just “odd”… We can speculate why this is so, but I will leave that to others. The important thing is that most “authorities” ignore the dangers that commensal rodents pose to human health and well-being, worldwide and here, closer to home. Maybe we need to explore the real causes behind it. Until we do, the lack of attention that results has consequences that affect human health and well-being.

My point? Don’t let the inattention of others cause you to drop your guard. We started this article on the premise that every thinking person needs command of a decision making process that improves their health and well-being and that of their loved-ones. Here’s something everyone should include in that process, and though you may not have thought it was that important before, give it another look. Control of commensal rodents at your home and business is crucial. Your health and the health and well-being of those around you are at stake.


Sadly, neither Google (via its Internet search algorithm), the Bill and Melinda Gates Foundation, nor the statisticians at the University of Southern California who oversee the graphs published by, seem to have a truly comprehensive understanding of what constitutes the most dangerous organisms on planet earth.

One thing seems sure. No matter how little attention others may pay to the facts, rats and mice are definitely up there, and are clearly among the greatest enemies most Americans and their families face.

What About Your List?

Remember that list of priorities you made at the beginning of this article, the one on that scrap of paper you folded up and hid in your billfold or purse? Pull it out now, and read it over. If, somewhere on that list you mentioned rats or mice, congratulations! You’re probably one in several million.

But, whether you listed commensal rodents on your list or not, they deserve to be there. If this paper serves any useful purpose at all, they will now become part of your mental list, the one that influences how you make important decisions that impact your health and welfare and that of those you love. As a result, your tomorrows may be brighter, more productive and healthier…

The evidence pointing to that is overwhelming. Read the material presented in E2M2C Chronicles for more on this topic…


  1. Commensal Rodents. University of Arizona, Cooperative Extension.
  2. Controlling Commensal Rodents. Dr. Ralph Kamel.
  3. The Significance of Commensal Rodents. PCT On-Line.


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