Guest News Brief by Kip Hansen – 29 July 2020
“What makes mosquitoes so dangerous? Despite their innocuous-sounding name—Spanish for “little fly”—they carry devastating diseases. The worst is malaria, which kills more than 600,000 people every year; another 200 million cases incapacitate people for days at a time. It threatens half of the world’s population and causes billions of dollars in lost productivity annually. Other mosquito-borne diseases include dengue fever, yellow fever, and encephalitis.” — this quote and this essay’s title come from the blog of Bill Gates:
A recent biology study asks the interesting question: “Why do some mosquitoes prefer humans?” The new study is titled “Climate and Urbanization Drive Mosquito Preference for Humans”.
Let’s hit the new study’s high point right from the start:
Despite the use of the word “climate” in the paper’s title, Climate Change does not drive mosquito preference for humans. Climate, however, has played a role in the evolutionary selection for the human-preferring sub-species of Aedes aegypti – which is the main insect vector that spreads Zika, yellow fever and dengue. (This is not the same mosquito that spreads malaria, that is the Anopheles mosquito.)
The NY Times coverage of study states : “The Current Biology paper focused on evolutionary history, but its findings might have implications for public health. The results, combined with climate and population data from the United Nations, suggest that there will be more human-biting mosquitoes in sub-Saharan Africa by 2050, caused mostly by urbanization.” When it says “there will be more”, what is really meant here is that the Aedes mosquito population will shift towards the human-preferring sub-species. The actual number of mosquitoes will depend on the effectiveness of (or lack of) mosquito control efforts of each urbanized area.
The reason they expect the shift is that the study found that the “more human-loving mosquitoes tended to come from areas with a dry climate and dense human population.” [NY Times]. In the areas of sub-Saharan Africa studied, the shift of rural populations to densely urbanized areas over the next few decades is projected to continue.
The hypothesis on how this came to be is based on the fact that mosquitoes need small pools of still water for reproduction. In drier climates, in which the rainy season is short, mosquito reproduction depends on human-supplied pools of water for much of the year – like flower pots, old tins cans, abandoned automobile tires and household water barrels. Urbanized areas thus supply not only the blood-meal needed by female Aedes for reproduction, by providing plenty of humans to feed on, but the small still pools of water needed for egg-laying as well. This two-barreled advantage, they believe, has favored the human-preferring genes (which they consider a sub-species) especially in these densely populated urban areas.
One of the authors of the study, Dr. Carolyn S. McBride, in this quote from the NY Times article, sounds disappointed that they were unable to blame Climate Change:
“I think it’s counterintuitive, because people know the climate is changing rapidly, so that should be the driving force,” Dr. McBride said. “But the features of the climate that we found to be important for this mosquito aren’t predicted to change in strong and clear ways that would affect the mosquito.”
Urbanization, in contrast, is occurring very quickly. “You could easily imagine that having an effect on disease transmission in big cities,” Dr. McBride said.
From the paper’s Summary: “Our findings suggest that human-biting in this important disease vector originally evolved as a by-product of breeding in human-stored water in areas where doing so provided the only means to survive the long, hot dry season. Our model also predicts that the rapid urbanization currently taking place in Africa will drive further mosquito evolution, causing a shift toward human-biting in many large cities by 2050.”
This study is really about the evolution of the Aedes mosquito and tracking the gene flow of the specific genes they have identified as being associated with the sub-species that seems to prefer biting humans (as opposed to other red blooded animals). The author team bravely tried to come up with a finding that would blame bad future outcomes on Climate Change (see the methods section of the study’s “Extended PDF”) but it was just no good. Model predictions of climate variables just didn’t change the finding: the shift had to be laid at the feet of human urbanization.
As with all modern news about mosquitoes, it is necessary to clear up common misunderstandings.
1. “….Aedes aegypti mosquitoes, which are responsible for Zika, yellow fever and dengue.” And, from the Bill Gates’ blog at the beginning of the essay: “they carry devastating diseases.”
Mosquitoes are not responsible for any of those diseases. Mosquitoes simply spread the disease from one infected host (usually human) to another host – mosquitoes pick up the disease from one infected human source and carry it around a while, then drop it off in another human. The diseases do not originate in the mosquitoes.
“…the infected mosquito carries the disease from one human to another (acting as a “vector”), while infected humans transmit the parasite to the mosquito, In contrast to the human host, the mosquito vector does not suffer from the presence of the parasites.” CDC
and
“people serve as the primary vertebrate hosts for Ae. aegypti and Ae. albopictus mosquitoes spreading chikungunya, dengue, yellow fever, or Zika virus.” CDC [my bold – kh]
The presence of mosquitoes does not mean the presence of mosquito-vectored diseases. For instance, Aedes aegypti [left panel] are found through much of the southern parts of the United States, yet we are almost entirely free of Zika, yellow fever, and dengue.
Today, dengue is only reported to be locally acquired in the very southern tip of Florida, where many residents come and go from the Caribbean Islands. So far this year, there has been one (1) locally transmitted case of dengue. [ source ]
The same is true for the malaria-vector mosquito, Anopheles:
As can be seen, malaria was ubiquitous throughout the Eastern United States in 1882, except for in the eastern mountain ranges. By 1932, it has been beaten back to a few hold-out areas, but broke out in 1934-1935.
After a long campaign against malaria, the CDC currently reports: “Now approximately 1,500 malaria cases and five deaths are reported in the United States annually, mostly in returned travelers.”
2. To nearly eliminate human cases of mosquito-vectored diseases is fairly simple in a country like the United States, and almost impossible in less-developed countries.
In the United States, humans sick with such diseases are taken to hospitals, where they cannot be bitten by mosquitoes and therefore cannot further transmit the disease. Neighborhoods where the disease showed up are heavily treated to knock out the existing generation of mosquitoes that might have been responsible for the transmission of known cases and the neighborhood is searched diligently for further cases. Then, with no (or very few) sick humans and few mosquitoes, there is no further transmission.
In the developing world, where health care systems have fewer resources and the people have less access to that system, sick people only end up in the hospital when they are already very sick (if then) and have, in all probability, already infected many local mosquitoes, who are busy infecting other humans. In this case, the procedure is for local officials to stage a wide area campaign of mosquito control by spraying, distributing treated mosquito nets, running a Anti-Mosquito Breeding Sites campaign, and bringing in nurses and doctors to find, quarantine and treat the sick.
A typical campaign poster (this one in the Caribbean) to eliminate breeding sites:
These campaigns are not limited to the Third World – see this Fight The Bite game from Miami/Dade County, Florida.
In my personal experience in humanitarian work in the Caribbean, the local officials almost never have the equipment or chemicals necessary for wide-spread mosquito control and have only limited, already-stretched-to-the-limit medical resources. It is heart-breaking.
The long fight against mosquito-vectored diseases has involved DDT – which itself is a very controversial issue – but is not the primary focal point of the fight. Many local mosquito populations have developed varying degrees of resistance to DDT. It is, however, still effective when used to treat indoor walls and bed-nets.
[And NO – “bringing DDT back” into wide use in Africa will not be an (or the) instant silver bullet solution to mosquito-vectored diseases. That is a myth. DDT is already widely used in Africa. ]
Permethrins Treat clothing and gear
-
- Use permethrin to treat clothing and gear (such as boots, pants, socks, and tents) or buy permethrin-treated clothing and gear.
- Permethrin is an insecticide that kills or repels mosquitoes.
- Permethrin-treated clothing provides protection after multiple washings.
- Use permethrin to treat clothing and gear (such as boots, pants, socks, and tents) or buy permethrin-treated clothing and gear.
For years, while living on our sailboat in the Caribbean, we regularly treated our hatch screens and cabin surfaces with permethrin – and had great success with it.
In the United States, synthetic pyrethroids are used in aerial spraying to control adult mosquitoes along with malathion and naled.
Mosquito-vectored diseases are a major, world-wide health problem and the use of insecticides in their control remains a hugely controversial topic at all levels of government and a matter of much concern from health and environmental groups. The controversies swirling around the issue are highly politicized.
One thing that is certain: The propaganda meme that Climate Change will spread mosquito-vectored diseases is categorically false and based on gross, seemingly intentional, misunderstanding of the mechanisms involved in disease spread.
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Author’s Comment:
I was reluctant to bring up DDT – in the past it has overwhelmed the comment section. I suppose it will again today, so I had my say on the topic. I will not be responding to the controversy in the comments here. After all, there have been whole books written on the topic, on both sides, and yet the controversy remains – it will not be resolved here.
On a personal note, I am allergic to mosquito bites. When I get them they swell up, they itch sometimes for weeks and if I get very many, I get body-wide allergy symptoms and have to rely on medication. Living in the Caribbean for so long was challenging. I nearly drove my wife crazy with my repeated rants and mania about mosquitoes. Suffice it to say: “I don’t like mosquitoes.”
All that said, neither my wife or I ever contracted any of the many nasty mosquito-vectored diseases endemic to the Northern Caribbean.
The featured study presents an interesting finding on why some mosquitoes like humans better than birds or dogs or goats.
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At least in my part of the Spanish-speaking world (the Southern Cone), mosquitoes aren’t called “mosquitos”, but “zancudos”. “Mosquito” refers to any small flying insect, such as a gnat or midge. For specifically the insects called mosquito in English, the word here is “zancudo”.
In Spain, mosquitoes are indeed called “mosquito”, but I do know about the “zancudo” word in use in South America. Not the first time I hear it.
Haven’t determined if fruit flies here are mosquitos or zancudos. Will ask someone.
Probably they’re zancudos if they bite.
In Chile, avocados are “paltas” instead of “aguacates”, strawberries are “frutillas” instead of “fresas” and babies are “guaguas” instead of “bebés” or “niños”. “Palta” and the onomatopoetic “guagua” come from Quechua, rather than any Chilean Indian language. The settlers had Peruvian Indian cooks and nannies.
The first time my Chilean wife and I were in Peru, she asked me what a “fresa” was. I told her that’s the Spanish word for strawberry. It’s “morango” in Portuguese, “amorogo” or “amodoro” in Galician (ancestor of Portuguese) and “maduixa” in Catalan (which looks more Portuguese than the Portuguese term), but as many here will know, “fraise” in French and “fragola” in Italian, from Latin “fragaria” or “fragum”, but also “arbutum”, the fruit of “arbutus”, the strawberry tree.
For malaria, HCQ!
Shown safe and effective against malaria, rheumatoid arthritis, lupus and porphyria cutanea tarda, since 1955.
Unfortunately it is no longer effective in many areas since the trypanosomes have acquired immunity to it.
Now you have to use other drugs like lariam which have considerably worse side effects.
True.
Eternal vigilance is needed against pathogens, whose powers of evolution are astounding.
Just a correction. Trypanosomes are the cause of various forms of trypanosomiasis such as Chaga’s disease, and African sleeping sickness. They are not treated by the drugs used for malaria. Marlaria is caused by Plasmodium species and Plasmodium falciparum is the most dangerous and the most resistant. In many areas where it is highly prevalent it is resistant to many of the earlier drugs including chloroquine but chloroquine remains active in much of oceana.
HCQ was in part adopted as more effective than chloroquine. Also better tolerated with fewer side effects.
Plasmodium, the malaria pathogen, is, like Trypanosoma, a genus of unicellular eukaryote, an obligate parasite of vertebrates and insects. But they’re in different phyla.
Two of the four Plasmodium species producing malaria have evolved resistance to chloroquine.
https://www.cdc.gov/malaria/malaria_worldwide/reduction/drug_resistance.html#:~:text=The%20development%20of%20resistance%20to,vivax.
HCQ against Chagas disease:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2844568/
Not just for malaria.
But resistance is a problem in a drug widely used for 65 years.
African sleeping sickness is spreaded by Tsetse fly, not mosquitos.
If you want to be protected against tsetse fly, try to have an zebra aspect.
Tsetse flies have no chance to see zebras.
Unfortunately, I don’t think the sleeping sickness trypanosomes can be treated with HCQ.
My tropical diseases teacher was visiting Stanford from Edinburgh, where he was the world’s leading expert on tsetse flies, which give live birth. Fascinating creatures, but lethal.
Re zebra stripes:
https://www.sciencemag.org/news/2012/02/mystery-zebras-stripes-finally-solved
Too bad that zebras aren’t domesticatable, to replace horses and donkeys in East Africa, but they’re both suicidal and homicidal.
Has anyone ever seen an environmental impact report on eliminating the mosquito? Their demise has pretty much eliminated the birds, bats, fish and amphibians that used to thrive on them.
Eliminating A. aegypti would have little or no effect on their predators. There are thousands of mosquito species. A. aegypti tends to breed where there are few fish.
Paul ==> There is seldom any effort to eliminate all mosquitoes. Many locales would like to eliminate human biting mosquitoes, especially those that act as vectors for human diseases.
In reality, eliminating sick humans eliminates these diseases.
Actually, here in Central Oregon, the Forrest Service, other Federal agencies and state agencies spray or have contractors aerial spray the forest and streams to eliminate mosquitoes so humans can recreate on or near the streams. Many years ago, no one could even go near the rivers and the open meadows in the forest without getting covered with mosquitoes. People could not build houses near the streams.
At the same time, there were masses of fat trout to be caught. The air was full of birds eating mosquitoes during the day and bats doing it at night. Frogs and other amphibians were everywhere eating them.
Now the birds that ate the insects have disappeared, the amphibians are endangered species, and bats are seldom seen.
Every other chemical use has required an environmental impact study, but never for mosquito spraying.
My granddad built the second cabin on the Metolius at Camp Sherman in the 1920s. It has a screened in porch as a refuge for when the mosquitoes were at their worst. The rest of the time, the fishing for my dad was great.
You cannot go into a Minnesota woods in the summer and not expected to covered by mosquitos. The fortunate part most do not carry disease. Most insect repellents are ineffective. The mosquitos are only a small part of the equation, the biting flies make it almost impossible to be in the wood in summer.
Biting flies are even worse on Central and Eastern Oregon streamsides than mosquitoes, in my experience. Fewer of them but much worse bite.
John, not just central and eastern Oregon. Biting flies are not a big problem in the valley but get up in the coast range and you’ll be swarmed by them at certain times of the year. You’ll be doing a jig trying to keep them from biting you. But I have to say the worst for me are the high mountain cascade lakes with their mosquitoes. I run screaming the other direction as soon as I spot a lake through the trees. No amount of repellent protects me from their overzealous attention.
These little bastards just showed up in my neighborhood last year in Southern California. This species is known here as the “Ankle-Biter” mosquito because they stay low to the ground. Unfortunately they attack all day as opposed to the type that just comes out at dusk. They can also bite through clothing and can reproduce in standing water as small as a teaspoon. Bring out the helicopters loaded with malathion, DDT, or just flame throwers.
Hoyt ==> Most mosquitoes re not long distance fliers. You do need to treat the neighborhood — they can fly about 100 meters (the consensus position on that…) and they can be blown in on the wind.
In the Caribbean, even near the marshy shore and lush vegetation, being anchofred out more than 50 – 75 yards was enough to almost guarantee mosquito-free living. When the wind blows from the shore, some would blow out into the anchorage.
Kip, there’s been 16 cases of dengue in Key Largo so far…..
.” So far this year, there has been one (1) locally transmitted case of dengue.”
“More confirmed dengue fever cases in Key Largo have brought the total number of infected to 16.”
https://keysweekly.com/42/dengue-cases-rise-in-key-largo/
Latitude ==> CDC and local officials often don’t communicate well. As the article explains, some infected individual apparently settled in Key Largo, transmitted the disease to local mos
Latitude ==> Oops – a vanished reply.
CDC often gets delayed reports. Some brought dengue to Key Large and the mosquitoes picked it up, spreading it. The article details the steps I mentioned on what developed world countries do in these cases. They isolate the sick, contact trace, and spray mosquitoes.
“The emergence of these dengue cases is reinforcing the importance for the public to prevent insect bites and to take basic precautions to help limit exposure. These measures include intact windows and screens and the use of air conditioning, keeping the area around homes free from containers that collect water, wearing protective clothing and the appropriate use of insect repellents.”
nope…we have our own strain….it has evolved to have a different genetic fingerprint…and is unique to the Keys
no one brought it here….it’s ours
Latitude ==> “Dengue is caused by one of any of four related viruses: Dengue virus 1, 2, 3, and 4. For this reason, a person can be infected with a dengue virus as many as four times in his or her lifetime.”
The reported locally transmitted cases in the Keys were DENV-1 which is not restricted to the Keys in any way. It does appear that there are occassional outbreaks of locally transmitted dengue there.
ok, I’m not going to go back and forth with you..about stuff you’re finding on the internet
Our virus is no longer classified as DENV-1
…it now has a different genetic fingerprint and is unique to the Keys and different than the rest….the RNA sequences have changed
It is now unique to the Keys…and not imported from travelers like it is up on the mainland
no one brought it here…our strain is unique to the Keys…it even has it’s own name
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3647415/
Latitude ==> The CDC does believe that dengue is endemic to Key West — and is DENV-1 dengue. This means that there are unidentified dengue-infected humans living among you — possibly asymptomatic. They established that the dengue is endemic (at lest in the 2009-2010 outbreak) through genetic sequencing.
Here, they are calling it the Key West DENV-1 strain….
it’s a different strain, not brought in by tourists, and unique to the Keys
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3647415/
kip, that’s not what you said…and not what I’m replying to
you said > “”The reported locally transmitted cases in the Keys were DENV-1 which is not restricted to the Keys in any way””
no, the locally transmitted cases in the Keys are ‘Key West DENV-1″…a different strain…and it is restricted to the Keys
we are tested for that particular strain
Kip
Thanks for the great article .
Mosquito-borne diseases MD are real, deadly and costly to the community .
COVID 19 is real, deadly and costly to the community .
There are preventative measures and treatments for both.
While cost of each MD prevention and treatment is well known for COVID-19 it has not even been considered.
I have no doubt the money spent fighting COVID-19 has been a horrible waste.
Waza
“COVID 19 is real, deadly and costly to the community .”
How ‘bout some updated statistics.
The data will set us free – or not. (CDC & WHO data)
Start close to home with Colorado.
Denver, Arapahoe and Jefferson counties account for more Covid-19 deaths than the ENTIRE rest of the state COMBINED!!!
Add the seven more in the top ten: Adams, Weld, El Paso, Boulder, Douglas, Larimer and Eagle and together these ten account for 89% of the total Colorado Covid-19 deaths.
Covid-19 is NOT a state-wide Scam-demic. It’s a problem for these ten counties with too many, too old, too sick, too vulnerable, too crammed together in contagious (BLUE) elder care facilities.
The state-wide social distancing, economic shutdown cluster ***, masked clown show is really^4 DUMB and totally UNJUSTIFIED!!
New York City, BY ITSELF, holds down FOURTH place in the GLOBAL rankings.
That takes some talent.
Covid-19 didn’t start in Wuhan, it began in NYC.
NYC, NJ, NY, MA, PA and CA account for more Covid-19 deaths than the ENTIRE rest of the country COMBINED!!!!
Add the three additional of the top ten, IL, MI and CT and they account for almost two-thirds of the country’s Covid-19 death count!!!
Covid-19 is NOT a nation-wide Scam-demic. It’s a problem for these ten jurisdictions with too many, too old, too sick, too vulnerable, too crammed together in contagious, poorly run (aka BLUE) elder care facilities.
The national social distancing, economic shutdown cluster ***, masked clown show is really^4 DUMB and totally UNJUSTIFIED!! Fauci does not know WTF he is talking about!!!
The US, Brazil, UK and Mexico account for more Covid-19 deaths than the ENTIRE rest of the WORLD!!!!
Add the six more to complete the top ten: Italy, France, Spain, India, Iran and Peru together account for 75%!!!!! of the GLOBAL Covid-19 death count.
Covid-19 is NOT a world-wide Scam-demic. It’s a problem for these ten countries with too many, too old, too sick, too vulnerable, too crammed together in contagious, poorly run (aka socialized) elder care facilities.
The global social distancing, economic shutdown cluster ***, masked clown show is really^4 DUMB and totally UNJUSTIFIED!! WHO does not know WTF they are talking about!!!
Nick ==> Appreciate your input — and know you were provoked. But, this is not the Covid thread.
Readers — there are plewnty of Covid threads to comment on, here and elsewhere, let’s try to keep this thread to mosquitoes.
“Covid-19 didn’t start in Wuhan, it began in NYC”
And you have a bridge for sale ?
Waza wrote, “Mosquito-borne diseases MD are…” and “While cost of each MD prevention…”
“MD” stands for what?
Dave
MD was my abbreviation for mosquito-borne disease . Sorry I wasn’t clear.
My point is prevention measures such as mosquito nets are funded based on well understood cost benefit analysis.
COVID preventions are not
As a fit 25 yo living and working in Malaysia I got dengue
One week in bed with horrible body aches.
Treatments, isolation, air con and paracetamol.
Sadly I have heard of many unhealthy Poor children Die from dengue.
Waza ==> There are two types of dengue infection -=- we have had friends get a “flu-like” version and some have near-death brushes with it.
Despite long-term exposure in the Dominican Republic and helping to fight a district-wide dengue epidemic, my wife and I escaped without getting the disease (which is good, we were both in our sixties…)
Stay away from infected areas. It is the second dengue infection that can be deadly.
Or take a vaccine. It is oddly enough only recommended for people who have already definitely had one infection, to decrease the risk of a second one. Not to people who haven’t been infected, since it isn’t 100% effective, and if not, can serve as a “first infection” making the next one dangerous.
Good to know. Thanks.
Deadliest animal in the world? People.
GLZ ==> Certainly up there. And, if we consider microbes . . . . ?
Although most microbes aren’t animals.
Also, most biologists don’t consider viruses to be microbes, since not “alive”. This even though they speak of “k!lling” viruses, and of “live” virus vaccines and of their “life cycles”. Technically, viruses are “replicants” rather than “organisms”, since they generally lack metabolic functions (except for probably relict genes in some of the largest DNA viruses). Other replicants include Mobile Genetic Elements (MGEs), such as plasmids, transposons, some bacteriophage elements and introns.
An estimated 50% of the human genome consists of MGEs.
Despite bacterial resistance to many antibacterial agents, viruses are a greater threat today than most bacterial infections. And despite eradication of smallpox and the ongoing extermination campaign against the polio virus.
As I use to say, there is only two animals I am really afraid of and take precautions against, humans and malaria typanosomes. And, yes, trypanosomes are animals, unlike bacteria.
Trypanosomes are eukaryotes, ie unicellular, parasitic, flagellate protozoa, but not animals (metazoa), ie multicellular, motile, heterotrophic eukaryotes.
True in the case of most infectious disease. Vectors like mosquitoes or fleas carry pathogens from one person to another. Or we transmit the viruses, bacteria or protists directly to other people.
Humans tend not to be moving when and where Aedes aegypti is most commonly feeding, ie at dusk and dawn, indoors, in shady areas or under cloudy weather.
Wear long sleeves and pants in A. aegypti country and sleep under a net soaked in premethrins.
The Modern English word “canopy” comes ultimately from the Ancient Greek for “mosquito”, via late Middle English, from Medieval Latin “canopeum” (ceremonial canopy), from the word’s Classical Latin meaning (mosquito net over a bed), from Attic Greek “kōnōpeion” (couch with mosquito curtains), from “kōnōps” (mosquito).
John ==> When we lived in the Caribbean, we stayed indoors, quite intentionally, at “mosquito feeding time”…. I often worked on deck until I heard the first buzzy little critter arrive and then I’d duck into the cabin, and button up all the screens.
Excellent anti-mosquito protocol!
In 1958 traveling on a P & O passinger ship Stratheden I was told by a fellow passinger that had been working on a Pacific island for 6 years that the100% cure for maleria was Gin & Tonic .
Kip
Speaking of screens, that is something you left out of your article. Yet, for anything larger than a noseeum, typical insect screen is very effective. Almost all homes in good repair in the US have screens on windows and have screen doors. Screening is much less common in Africa. I have a friend who has been teaching in Africa, most recently Ethiopia, and while the university was putting him up in relatively nice hotel, it had neither A/C or screens on the windows.
Clyde ==> Yes, no glass, no screens, no doors that seal, no refrigerators that are cold inside, no available medicine and when available, not affordable.
Has the same experience in the 1970s doing port surveys for our ship while staying in one of the best hotels in Port au Prince, I got bitten by a something that left an oozing wound at lasted several weeks and resisted healing.
Kip
That sounds like a spider bite.
Clyde ==> Yes, I had to go to a local Haitian doctor at the time – that was his guess too. It was worse than I made it sound, almost had to abandon our port survey and return to the ship.
DDT
DDVP—-been using it for 60+ yrs.. It was the active ingredient used in the
Shell No Pest Strip, remember those.? My dad bought a gallon of
the concentrate back in the 60’s for his annual fishing trip up north where the mozzies
are reputed to be the state bird. He also got a hot fogger to apply the stuff..diluted to
1%. The label is mostly still the same except a licence is required to buy the concentrate but
the diluted mix is available but expensive.
He would walk around the fishing camp applying the stuff
in a hot fog which in turn would make the bush a no pest strip for several days. It made
a huge impression with the guys on the trip, I still use it on occasion as needed, I lost a nice
horse a few years ago to west nile even after 2 vaccine shots…and I’ve had a case of
west nile also..thought I was going to die.
It also is used in a diluted liquid form in a barn on walls floors ect. flies, bees ,mozzies ect
Better living through modern chemistry..
Do we have evidence that GM mosquitoes tech is viable, or evidence of the contrary?
Jurty still out as to effectiveness, based upon Brasil results, but opposition predictable:
https://www.sciencemag.org/news/2019/09/study-dna-spread-genetically-modified-mosquitoes-prompts-backlash
Plans for release in FL and TX okayed:
https://www.theguardian.com/environment/2020/jun/17/genetically-modified-mosquitoes-florida-texas
John ==> Thank you for fielding the question. I have covered this in earlier essays on mosquitoes.
Another interesting question is why mosquitoes like biting some people and not others. It’s unlikely to be genetic, because my sister and I were polar opposites: she’d get eaten alive during walks through our woods, and mosquitoes would rarely even land on – let alone bite – me. In my 66 years, it has been a constant. I have almost never had a mosquito bite, even though I’ve spent a lot of time outside in places heavily populated with mosquitoes (e.g. Missouri, Florida, Indiana).
Possibly scents, carbon dioxide and water vapor exhaled, body odor body temperature. Steam rising from a boiling kettle attracts a column of mosquitoes, while camping. Warm, moist air is part of their search algorithm.
Michael ==> The common held view is pheromones — or as John says — body odor. There is a huge difference in “attractiveness” between individuals.
Yes. I should have broken BO down into its pheromonal and organismal components.
Whether pheromones or bacterial ecology on our skin, the little bitches (all bloodsucking mosquitoes are female, using our blood proteins to make their eggs) prefer some biochemical smells over others.
Also could have added colors. The suckers are attracted to darker colors such as black or blue over lighter shades, such as white or tan.
It also changes over time. When I was a boy my father thought I was making unnecessary fuss over mosquitoes because he was rarely bitten. Twenty years later it was the other way around and it was he who was always complaining about mosquitoes, while they didn’t bother me much.
One insect and disease that has not been mentioned that come from South America is leishmaniasis and is carried by sand flies. One variation of this disease can eat your face leaving a gaping hole where you nose, mouth, eyes, and facial bones use to be – this disease is now in Oklahoma and Texas moving Northeastward and to some degree southwestern. Malaria is a terrible disease but this one takes the cake – we need to make sure we are not disregarding this little known illness because most of the people who have it are very very poor people in Honduras and other Central American countries. Scientists need to find a vaccine or medication to stop this disease as there are no good alternatives for it – the drugs they do have can kill you before they cure you and sadly to say you are never cured of this parasite – it stays in your body forever and can reappear at any time.
Maybe entering the US from South America, but where it originated isn’t known. It has existed in the Middle East and Indian subcontinent since ancient times.
Again, sleep under a pesticide-impregnated net in areas where sand flies are active.
DEllison ==> The CDC has a page on leishmaniasis . There have been “occassional cases” in Texas and Oklahoma.
” In drier climates, in which the rainy season is short, mosquito reproduction depends on human-supplied pools of water for much of the year – like flower pots, old tins cans …. ”
Up here in the dry tropics of North Queensland, these pools are targeted by the “authorities” but there is a major omission, which is below ground level infrastructure service pits belonging to telecommunication providers, and irrigation boxes and the like, many of which are the responsibility of, but ignored by, the local government agencies who are the enforcers out there, busy issuing fines for infringements occurring in domestic spaces. I used to tip mozzy deterrent into the telephone pit in front of my property, but that is no longer available, and I don’t think it is a good idea to replace it with kerosene.
Anything that makes a persistent oily film on the surface would probably work. You might try olive oil.
Martin – tty ==> There are lot of surface treatments effective against breeding mosquitoes.
Had another look at what is recommended here; health.gov.au reports that only the larvacide s-methoprene is registered for use in rainwater tanks. It does not recommend vegetable oils as they easily become rancid (especially up here). Kero can coagulate, and also affects some tank materials. I think I’ll invest in some sealable lids with 1mm gauze for the unprotected tanks. The problem with the service pits is that the lids on even newer ones have holes for the lifting gear.
Technically, the mosquito vectors of lethal diseases aren’t all the same animal. They’re not only different species but in different genera. It’s as if “apes are the most dangerous animal” were the claim.
Aedes, Anopheles (malaria), Culex, Culiseta, Haemagogus and Ochlerotatus genera all include disease vectors.
Was for a while considered a subgenus of Aedes. Carries a host of pathogens:
https://en.wikipedia.org/wiki/Ochlerotatus
Carries yellow fever virus and other viral pathogens:
https://en.wikipedia.org/wiki/Haemagogus
Cold-adapted:
https://en.wikipedia.org/wiki/Culiseta
North temperate zone vectors of arbovirus infections such as West Nile virus, Japanese and St. Louis encephalitis, but filariasis and avian malaria as well.
https://en.wikipedia.org/wiki/Culex
Even if all these genera were wiped out, there would still be no shortage of mosquitoes for bats, birds, reptiles, amphibians and fish to eat.
On a personal note, I am allergic to mosquito bites. When I get them they swell up, they itch sometimes for weeks and if I get very many, I get body-wide allergy symptoms and have to rely on medication. Living in the Caribbean for so long was challenging. I nearly drove my wife crazy with my repeated rants and mania about mosquitoes. Suffice it to say: “I don’t like mosquitoes.”
Kip I hear you on this, that’s me to a T. I’ve had bug bites still swell up, get itchy & red/bleed as if it was a fresh bite, 6 months afterwards! Turns out I have mast cell activation syndrome/disease – you might have something like this. Anti-histamines help a lot but you’ll need to take them daily, it helps reduce the huge over-reaction and makes you feel better. I’ve been taking antihistamines for 2 yrs now wish I had known sooner. Now if I get a bite, I hardly notice or it’s over with in a normal few days time. I get deer fly, tic, gnats and mosquito bites as we live in the country, I can now enjoy gardening again as I had given it up; the bites made me so miserable.
ldd ==> Thanks for the tip —- I’ll talk to my physician.
Up here in Canada I bought a $15 item called a Therapik. It uses contact heat to denature the proteins in the insect bite that cause the swelling. Very effective for all biting flies. Just need to press it to your skin for 30 seconds or so until you can’t bear it any longer. May need to do it a second time.
Doug => Thanks, I’ll check it out.
If you let a mosquito suck, she will usually withdraw the anticoagulant which causes the blister and itching. Then smack her and be amazed at the amount of blood. Or if possible, tighten tissue enough so that she can’t pull out her proboscis and watch her explode. Enjoy the blood spatter pattern.
“After all, there have been whole books written on the topic, on both sides,” yes, some propaganda on one side and some science on the other … moral coward …
The Dark Lord ==> It is not always necessary to ignite controversy in the comment section. I stated my opinion quite clearly and will leave it at that. Your accusation is out of line.
Kip yet again got a useful discussion going without much sidetracking. He’s not a coward. He has written on the DDT issue elsewhere at length.
John ==> Thank you, sir.
De nada. Es la verdad.
John ==> Are you, or do you have friends, in Central America? Guatemala?
Not Guatemala, but Costa Rica and, unfortunately for them, Nicaragua.
Plus, I sometimes cycle through Panama.
John ==> I asked because I has a research question: How much does an adult goat cost in Guatemala? Any idea? any of those countries will have similar values….
“As professor of epidemiology at Yale School of Public Health, I have authored over 300 peer-reviewed publications and currently hold senior positions on the editorial boards of several leading journals. I am usually accustomed to advocating for positions within the mainstream of medicine, so have been flummoxed to find that, in the midst of a crisis, I am fighting for a treatment that the data fully support but which, for reasons having nothing to do with a correct understanding of the science, has been pushed to the sidelines. As a result, tens of thousands of patients with COVID-19 are dying unnecessarily. Fortunately, the situation can be reversed easily and quickly.
I am referring, of course, to the medication hydroxychloroquine. When this inexpensive oral medication is given very early in the course of illness, before the virus has had time to multiply beyond control, it has shown to be highly effective, especially when given in combination with the antibiotics azithromycin or doxycycline and the nutritional supplement zinc.”
The above is the opening of an article which is well worth reading by Professor Harvey Frisch in Newsweek . Rather than risk being accused of the fallacy of arguing from authority I would recommend that people read the article themselves and follow the links to the evidence he cites.
Alan ==> Can you supply a link. Google search and searching the Newsweek Magazine site directly turn up nothing.
BTW — this is not the Covid thread — but I would appreciate the link now that you weighed in.
My apologies, I posted this under the wrong article.
http://www.newsweek.com/key-defeating-covid-19-already-exists-we-need-start-using-it-op535inion-1519
Censorship strikes again.
That link goes to Newsweek but only provides the message
PAGE NOT FOUND
I’ve been seeing a lot of this lately.
I searched using duckduckgo browser and I found it! Sometimes we have to be smarter than the machine.
https://www.newsweek.com/key-defeating-covid-19-already-exists-we-need-start-using-it-opinion-1519535
IAMPCBOB ==> Thank you — great job,
Alan ==> Thanks no worries. Always glad to have your input.
https://www.foxnews.com/media/hydroxychloroquine-could-save-lives-ingraham-yale-professor
This article provides great perspective and is well worth the read. Urbanization is one of the most important changes in modern society and has, in many ways brought significant new problems, but ones which, in the passage of time, human ingenuity has general found solutions for. These include air, land and water pollution, increased automation with reduce human activity which, along with dietary changes led to an epidemic of obesity, increased population densitiy facilitating the spread of many high risk infections (including CoVID), and, in my opinion, a separation of most populations from experience and knowledge of primary production processes which support society, leading to ignorance and poor decision-making about the support of maintenance of those processes.
Andy ==> Urbanization in the Third World really means millions of profoundly poor people pouring into already crowded cities that lack proper infrstructure like clean water, sanitary sewers and electricity.
I agree this is part of the pattern but if we get busy and start providing electricity, services and economic opportunity we can help these nations move forward in ways that solve those problems. China has made a lot of progress on that path but with lots of the issues I mentioned still to solve. In most cases in poor countries people move to cities because it is better than what they leave behind. We need to help them make urban life a better life and solve the problems that cities create. History tells us this is all doable if we stop focusing on imaginary problems and creating unjustified barriers such as the prevention of investment in cheap electricity and preventing the use of resources to move forward. We in the developed world seem to be saying the poor should stay poor because of a religious belief that humans harm the earth whenever we make our lives better.
China, India and other developing countries would benefit from improving rural opportunities, to stem the tide into megacities.
People are now fleeing NYC, the world’s first megacity. Who knows how many widll return?
Yellow Fever was effectively eliminated as a threat with the live, attenuated YF-17 virus vaccine called YF-17d.
YF does nor spare children like SARS-CoV-2, and the neurologic sequelae with severe YF are substantial in many recovered patients.
Even though the US military and WHO recommends giving it every ten years to at risk people, T-cell memory responses to the vaccine in vaccinees has been found 60 years later.
Attenuated live virus vaccines work. And work quite well.
True, but dengue vaccines based upon YF-17 are still not up to snuff. However, dengue isn’t as deadly as yellowjack.
Coronavirus vaccines will probably need boosters and won’t last 60 years, if animal CoV vaccines are any indication. While RNA viruses, they’re far removed from yellow fever virus and its kin.
The Dengue vaccines are certain to fail because of the inevitable non-neutralizing antibody dependent enhancement (ADE) of a related infections within the 4 DV serotypes.
Thanks!
If all they do is fail, without causing death, that’s a better than worst thing.
Of the “plague” bugs I’ve endured in the bush the worst in the Canadian Shield are:
Black flies–the have a pain killer in their saliva and you can’t feel their bite.
They don’t care if you are moving or not–they will get your one way or another.
Next mosquitoes. Keep moving and you will be OK.
Horse Flies — When their fuselage length approaches one-inch they are called Super-Bulldogs.
They don’t so much sting as bite.
Right through blue-jeans.
Ooops bad memories.
Out of here!
Bob
While I spent my early childhood in northern Illinois, I didn’t know what a noseeum (black fly?) was until I was stationed in New Hampshire while in the army. They can be much more annoying than mosquitoes! However, I later discovered that the sand fly bites in New Zealand were worse than noseeums! I started wearing long-sleeve shirts and gloves with insect repellent sprayed around my wrists and ankles while in the bush.
Something went wrong with that link. The 535 should be at the end not in the middle of the word opinion.
Great article Kip. Good comments too. It’s a subject I’ve studied and always been interested in and it jogged my memory back.
Over the years I’ve noticed that midnight mosquitos seem inclined towards biting children more than adults and I reached that conclusion after spending a decade of summers in a holiday apartment with assorted family.
One young nephew was covered in bites all over his back, I put some TCP liquid on the bites and the swelling subsided in 30 minutes !!
Tim ==> Had to look up TCP — phenols . .. . I’ll have to get and try some.
Kip – great article – Bats are the best “natural way” to manage mosquito population. In a article on http://savetheeaglesinternational.org I summarized the problem of Industrial Wind Turbines killing bats and birds:
Birds and bats are being killed at an astonishingly increasing rate as the number of industrial wind turbines increase.
– Mosquito populations are rising at an alarming rate.
– Bat kills in one location can impact locations thousands of miles away.
– Bats are long lived and slow to reproduce. Scientists are worried that some of the most useful bat species (e.g. Hoary bats) will not recover and become extinct – Fatalities at wind turbines may threaten population viability of a migratory bat
– Birds and bats provide a natural way of keeping mosquitoes and other problem insects (e.g. Lyme disease ticks) in check.
– Mosquitoes spread diseases like Zika, Malaria, and West Nile Virus. These diseases are spreading throughout the US and Europe.
– Communities are beginning to increase chemical spraying, including aerial spraying of Naled over millions of acres in the US. Naled is toxic to bees and butterflies. The European Union banned Naled in 2012, citing “potential and unacceptable risk showed for human health.”
– Politicians and Industrial Wind companies are not going to give in easily, as billions of dollars (and euros) in subsidies are at stake.
Tom ==> I like birds and bats. Wind Turbines kill too many of both.
Interesting article, thanks for posting.
Here in France all you hear about is the relentless spread of what we call the “moustique tigre” due to climate change. I presumed it was yet another one of their seemingly endless “worse than we thought” type ideas, so reading your thoughts about it was very educational.
I’d be interested to know what you think about the latest research into mosquito sex change, female to male, which can be seen here :
https://www.pnas.org/content/117/30/17702
CB ==> I’ll have th leave that question to John Tillman too far outside my expertise. Interesting though.
Or in this case, “u”, as in “m@rder”.
See below. Was double secret probationed for both the K and M words.
CB,
Transgenic change has been studied as a possible vector population control in A. aegypti:
https://link.springer.com/article/10.1186/s13071-018-3217-6
Your invasive mosquito species might be this member of Genus Aedes, native to SE Asia and named for its stripes:
https://en.wikipedia.org/wiki/Aedes_albopictus
It has spread to infest much of the world.
In the US, we have “murder hornets”, the killer bees and fire ants of the 21st century.
Oops! Forgot to replace the “i” in the word which shall not be named.
I got malaria when I was 7 years old. We were living in Quetta, Baluchistan at the time. We visited Rawalpindi, my birth place, for a short holiday. That’s probably where I caught it. Malaria is not a nice thing to have. I was close to death and had major hallucinations.
It came back to bite me every now and then until I was 15 or 16. It’s debilitating. Each time I was in a bad way – fever, sweating, not knowing where I was, etc. I was lucky that I got the milder form. The really bad form kills you. I’ve long thought that the really bad form would also recur, but you’re dead, so it can’t.
I’m sorry to raise the spectre of DDT, but I have to. It was killing the malaria mosquitoes and saving lives and getting close to eradicating malaria. Then it was banned in 1962 or around then and the malaria deaths since then, if we use the 600,000 per annum number, would be around 35 million and most of the victims are poor African children.
It wouldn’t surprise me to learn that the people who banned DDT, leading to the deaths of 35 million African children, are the same people that want to deprive poor Africans of electricity.
One thing I’ve never understood about mosquito control is why we have no simple and effective trap for eliminating mosquitoes around dwellings. Mosquito host response and acquisition seems to be relatively well understood and medical entomologists have been sampling mosquito populations with awkward CO2 light traps for generations. Some advances have been made with other chemical attractants, but nothing that I have seen has been designed to protect people in their backyards and homes.
What is available are snake-oil type hypersonic or UV-bug grill type traps – all useless. There are the allethrin-type thermal dispersants for ‘repelling’ mosquitoes, and my experience with them in Canada suggests they do have short-term repellent properties, but then you have to breathe in a noxious chemical too. Same for coils, citronella, etc, except they are less effective.
Why has no one devised a simple and effective trap for mosquitoes attracted to humans? There would be a giant market in the entomophobic first worlders; real health benefits wherever La Crosse, West Nile and assorted encephalitic viruses are present; and the public health benefits would be enormous in less developed nations. Any selective force would probably be towards avoiding humans rather than becoming resistant to the trap. Really, this is a void in applied medical entomology. Some engineers and medical entomologists need to get together and get creative.
Dave ==> As you say, no one has yet come up with one . . .
Kip wrote, “…It is heart-breaking.”
For canines, felines, and some other animals, mosquito bites can be literally heart-breaking, because they carry heartworm infections.
With the lockdowns there have been a resurgence of the mosquito driven tropical diseases since people are inside and not emptying the pools of stagnant water around houses.
They should use CRISP to eradicate these little pests off the planet. I am sure the other bugs and fish can eat other bugs than mosquito larvae.
By the way, the Aedes aegypti doesn’t really hide during the day and is so aggressive. In a mater of seconds that little fu*** bit me 5 times on one hand… that’s when I got my first tropical disease… dengue fever. Really no fun. Spent 5 days in hospital and took months to really get back to normal.
Raymond ==> My wife and I lived in a Dengue Endemic country for ten years — and helped fight a localized dengue outbreak providing humanitarian aid to buy pickup-truck-mounted and backpack sprayers and anti-mosquito chemicals — miraculously, we never got dengue or any of the other nasty tropical diseases in vogue there,
Raymond Bélanger ==> If people are really staying in their houses. Have we got data that shows an uptick in tropical diseases?
Kip…
https://asia.nikkei.com/Spotlight/Coronavirus/Singapore-grapples-with-dengue-fever-while-battling-coronavirus
Raymond ==> Ah — Singapore has apparently stopped its spraying and regular maintenance practices such as those to prevent stagnant pools of water, etc.
“The spread of COVID-19 among foreign laborers has led to grass going uncut at parks, creating a more hospitable environment for mosquitoes, while standing water at idle construction sites gives them more places to breed.
The agency is working to control mosquito populations through steps including spraying pesticides and removing stagnant water.”
Anytime a tropical country falls behind in anti-mosquito measures they risk an outbreak. The idea that they have quit mowing the grass because foreign workers are ill is probably not true … have they laid them off or locked down?
LOL.. most likely kicked them out…
Kip..
also: https://www.nea.gov.sg/dengue-zika/dengue/dengue-cases