Sciencemadness Discussion Board

Attacking the vector - Mosquitoes

un0me2 - 3-5-2010 at 16:23

A very interesting article is this one, where they play around with transgenic modification of Aedes Aegyptii Mosquito's (the #1 vector for yellow fever & Dengue Fever). Without going too far into the detail, they found that Delta-Relish (??) modification led to almost total immunodefficeincy post-feeding.

What is more interesting, from the point of view of effective control of wild-type mosquito's (there is a large body of opinion that modified mossies will not be strong enough to compete for mates, etc.), is that non-modified mosquito's ALL died within 48 hours of being exposed to P. Aeruginosa:
Quote:

Survival experiments with the transgenic mosquitoes showed a marked susceptibility to Gram-negative infections (E. cloacae, E. coli, and P. aeruginosa) (Fig. 4 A). All RMID transgenic mosquitoes injected by Gram-negative bacteria did not survive beyond 24 h postinfection. The parental UGAL strain showed <40% lethality to the injection of E. cloacae and E. coli and less susceptibility than the transgenic mosquitoes to the injection of P. aerusinosa. This human opportunistic pathogen is highly pathogenic to Drosophila (20) and even killed all of the wild-type mosquitoes in <48 h. The susceptibility to Gram-positive infection was not markedly different between the transgenic and wild-type mosquitoes in the present experiment (Fig. 4 A). All three Gram-positive bacterial infections could not kill >50% of both wild-type and transgenic mosquitoes.


Now, P. Aeruginosa is EVERYWHERE:
Quote:
P. aeruginosa is often preliminarily identified by its pearlescent appearance and grape-like or tortilla-like odour in vitro. Definitive clinical identification of P. aeruginosa often includes identifying the production of both pyocyanin and fluorescein, as well as its ability to grow at 42°C. P. aeruginosa is capable of growth in diesel and jet fuel, where it is known as a hydrocarbon-utilizing microorganism (or "HUM bug"), causing microbial corrosion.[6] It creates dark gellish mats sometimes improperly called "algae" because of their appearance


Now that suggests to me, that this may well be the key, after all we already use fogging with some seriously unhealthy chemicals to control the Aedes Aegyptii Mosquito (in the northern part of Australia, predominantly on the East Coast). Using fogging with a natural, endemic human bacterium, which has far more effect on the mosquito than on the human (or anything else) for the most part, might be an effective answer.

Human susceptibility to this pathogen is known to occur, but that is mainly due to the fact that it is known to occur wherever there is human habitation and to infect human skin already. It is effectively an "endogenous" pathogen, so increasing the levels of it in the air should not seriously affect humans (certainly a lot less than drug-resistant malaria, let's put it that way).

In fact there is study going into this now, while the use of P. Fluorescens against the vectors of Japanese Encephalitis, etc. is also being investigated.

It will be very interesting to watch this, the use of pathogenic agents we carry on our body anyway to destroy a major source of serious virus vectors, is interesting in its own right. Put simply, despite being quite problematic pathogens in their own right, they affect only those people who would be much more susceptible to death via malaria/dengue fever anyway. The use of the Pseudomonas Spp. would be less problematic than the other bacterial agents that are being investigated, as it is much more robust in the environment.

[Edited on 4-5-2010 by un0me2]

not_important - 3-5-2010 at 17:50

Relish
Quote:
Relish was identified in a screen for genes involved in the Drosophila immune system by using PCR differential display to identify genes induced in infected flies. Unlike the single domain proteins Dorsal and Cactus (respectively the classic NF-kappaB- and IkappaB-related proteins of Drosophila), Relish contains both a Rel homology domain (hence the name Relish) and an IkappaB-like domain with six ankyrin repeats. Thus Relish is a dual domain protein. In this respect Relish is similar to the compound mammalian NF-kappaB precursors p100 and p105, although no obvious similarity is seen outside the two conserved domains


http://www.sdbonline.org/fly/torstoll/relish1.htm


Adaptive Evolution of Relish, a Drosophila NF-{kappa}B/I{kappa}B Protein
http://www.genetics.org/cgi/content/abstract/154/3/1231

Interesting stuff

JohnWW - 4-5-2010 at 15:42

I would like to know about any such insecticides, or biological control agents, specific to mosquitos, too. In spite of the drought, in my part of New Zealand, there have been unprecedented numbers of mosquitos, al;l the past spring, summer, and autumn, forcing me to buy large amounts of mosquito repellants (picaridin and bicycloheptene derivatives) and insectide (pyrethrins + piperonyl butoxide) sprays.

New Zealand has 7 native species of relatively harmless mosquitos, some of which may also occur in Australia, but they are all very aggressive toward humans. A few years ago, there was a scare over an Australian species, the salt marsh mosquito, from Queensland arriving and breeding in New Zealand, which is a carrier for the Ross River fever, but they have since been all exterminated. They probably arrived in water inside tires on ships, either as imported new tires carried as deck cargo or used old tires used as buffers around ships' hulls, although they may have been blown across the Tasman Sea by storms.

A particular worry is, still, the possibility of arrival in New Zealand of the Aedes Aegyptii mosquito, which is the principal carrier of malaria, dengue, and yellow fever, and which could survive and breed in my part of New Zealand. This is especially as they are already on the east coast of Queensland, and probably making their way south, ironically the area most affected also by introduced cane toads.

[Edited on 5-5-10 by JohnWW]

un0me2 - 5-5-2010 at 13:44

One type of Aedes Aegyptii borne-Dengue is prevalent in Cairns & the other in Townsville (quite probably derived from that from the Solomon Islands, given Townsville was THE R&R center for troops infected with Dengue from the Solomon's campaign(s) in WWII). Get one type then the other, and dengue hemorrhagic fever is a real possibility, this shit makes malaria look like fun, it is also recurrent, drops you hard as fuck and hurts like a bastard.

What I am looking at is that this pathogen KILLS ALL the mosquito's it infects, even in the wild without the need for ANY genetic manipulation of the mosquito itself. Thus we avoid the potential (real or imagined) of inadvertently creating "super-mozzies", or rather more likely, of costly failures. This pathogen lives in diesel/kerosene, which would be a rather useful fogging agent, as it would form a layer on top of water, then evaporate slowly, allowing the pathogen to enter the water itself, thereby infecting the pupae.

It would also presumably fall onto and then attach itself to adult mosquito's, but that is of lesser potential realistically. The spraying/fogging with rather nasty chemical combinations that goes on every year in NQ/NT, etc. are probably going to prove to be a greater threat to health than a spray containing nothing more than a basic solvent containing an endogenous pathogenic bacteria. Yes, it may (and quite probably will) affect those with compromised immune systems, but probably to no greater degree than the fogging, whilst having the potential to be far more effective in preventing the mosquito breeding cycle (people with compromised immune systems fall victim to Dengue & Ross River rather easily too).