Swine Flu, AIDS, and Mosquitoes

A recent reoccurrence of a dangerous strain of The Flu, called Swine Flu, brought out unfortunate speculations about the causes of it. This particular strain of the flu is extremely virulent, and a large number of people who contracted it were killed by it. The moment it was discovered as a form of the Swine Flu the news media quickly reported its similarity to outbreaks in the 1900’s that killed tens of millions of people around the world, and a mild panic began. With any panic we can expect misinformation, and such was the case with this Swine Flu of 2009. A glance around the internet found many chat rooms and websites that told us that insects, such as mosquitoes, are a likely means by which the disease is being spread from person to person. This absolutely is false. 

 

This seems to be a common theme, that blood feeding insects are vectors of any and all diseases that seem to be making the news. When AIDS was in its early years in the United States it was widely reported that mosquitoes, fleas, and bedbugs were spreading it from person to person, and yet even to this day reputable health agencies will tell us there is no evidence whatsoever that this can happen. When West Nile Virus began to occur in North America, a disease that definitely IS vectored by mosquitoes, there was speculation that the mosquitoes, the virus that causes the disease, or both were genetically engineered biological terrorist weapons, released into the U.S. just to kill people. This is dangerous speculation, but unfortunately it often makes popular media and is easily believed by people who fear the diseases. It is a fact that blood feeding parasites, such as mosquitoes or bedbugs, would certainly be capable of ingesting blood infected with these serious disease pathogens, but there is no evidence, despite intense study of it, that they are then capable of passing those pathogens onto another host animal – a person.

In the case of swine flu there is no evidence at all that any insect is capable of spreading it from human to human by means of a bite. The insects that serve as vectors of disease are well known, and the diseases associated with them are usually distinct for that kind of insect. Only mosquitoes can spread malaria, yellow fever, dengue, or encephalitis. Only body lice can vector epidemic typhus. Only ticks can vector Lyme Disease and Rocky Mountain Spotted Fever. Only fleas can vector bubonic plague. And, none of these has any role in the transmission of the flu. The speculation is that it would seem logical for a blood feeding insect to ingest infected blood from a person with a disease, and then pass it onto the next person that insect feeds on, as happens with the known insect-borne diseases. However, if this were the case then logically mosquitoes also could spread chicken pox, measles, mumps, or the common cold, and none of these are realistically associated with these insects either. The simple reference to mosquitoes as just “hypodermic needles” does not do justice to the actual complexity of their biology.

 

Why is this the case, for there is a very good reason that insects do not spread all diseases of humans? The answer is that the pathogen – that microbe that causes the disease – and the insect that is capable of transferring it from person to person, must have evolved together and have a very intimate relationship with each other. In most cases the pathogen MUST live part of its life within the host insect, as part of its normal biology and development. In the case of AIDS, the flu, or other typically human diseases, the pathogen is only an accidental visitor inside that mosquito or other blood sucking pest, and once ingested by the insect the virus or bacteria is quickly passed out as excreted material. There is no mechanism for the insect to pass that pathogen back into a second blood host human.

Compare this with the virus that causes West Nile Virus for example, a form of encephalitis. Somewhere in nature there is a “reservoir”, or a source where the virus sustains itself, and for West Nile Virus this reservoir commonly is within birds. A mosquito that feeds on birds may ingest the virus, which ends up in the stomach of that mosquito. The virus then enters the lining of the gut of the mosquito where it lives and reproduces, increasing its numbers dramatically. The virus then migrates to the salivary glands of the mosquito where it can be passed out as the mosquito feeds again, entering the blood stream of this new host animal. The reason the virus is able to make this circuitous route is because it has spent millions of years doing so, and perfecting that practice as a natural part of its own life cycle. The virus must be within the mosquito for this to happen, and for it to survive. Incidental pathogens such as the virus that causes the flu do not have this kind of relationship with insects or any other blood feeding arthropod, and cannot be transmitted by them.

It is very important to be skeptical of wild claims that you hear, and with the wealth of valuable information available on the internet there is, unfortunately, also a wealth of fraudulent information. Filtering through this can be difficult, but your best course of action is to look to reliable sources. For anything having to do with human health one excellent agency is the Centers for Disease Control (CDC), and another is the World Health Organization (WHO). Both of these can be counted on to offer information that is both current and accurate. You often can find local or state health department websites that also would be reliable, as well as many university websites. These may take longer to place new information on new events onto their websites, but what is found there would be information you can trust.

 

What you can NOT rely on is the headlines you see at supermarket checkout counters, where the sensationalistic news media are placed for easy reading. These offer outrageous information that may be fun to read, but should never be counted upon to be truthful. On the internet avoid personal blogs or other websites, such as chat rooms, that are filled with personal opinions. This may be where false rumors get started. There also is a constant flow of disinformation circulating throughout the internet and email systems, and it pays to check for validity on one of the many hoax busting websites before passing these curious emails along to others you know. BugInfo articles are presented by a reliable source, and as an affiliate of the professional pest management industries it is our goal to help educate people on insects, rodents, and other organisms that pester us, and provide information you can rely on.