Diseases and Cures in the Wings of Houseflies

A checked version of this page, approved on 28 July 2013, was based on this revision.

This article analyzes the apologetic claim that the sahih hadiths concerning the wings of the housefly are somehow scientifically accurate.

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Electron micrograph of bacteriophages attached to a bacterial cell.

Muslim Claim

The thesis put forward by some Muslims is that it has recently been proven by modern science that flies carry not only pathogens but also the agents that limit these pathogens, thus proving the fly wing hadiths:

As narrated from Abu Hurayra and Abu Sa`id al-Khudri by al-Bukhari and in the Sunan, prophet Muhammad said: If a fly falls into one of your containers [of food or drink], immerse it completely (falyaghmis-hu kullahu) before removing it, for under one of its wings there is venom and under another there is its antidote.(Sahih Al-Bukhari: Volume 4, Book 54, Number 537)

They principally identify these agents to be bacteriophages, though they also sometimes refer to fungi.

To bring the layperson up to date, bacteriophages (“phages”) are viruses that infect bacteria. It is a generality that all natural bacterial populations are limited by phages and environmental conditions, but it is a leap to suggest that these elements are antidotes. Mammals, too, are limited by pathogens, but it is foolish to suggest these pathogens are antidotal to mammals.

Analysis

Dissection of the fly wing hadiths is as follows:

Which wing contains the venom and which the antidote?

Ibn Hajar wrote in his commentary on the hadith:

I found nothing among the variants to pinpoint the wing that carries the antidote but one of the Ulema said he observed that the fly protects itself with its left wing so it can be deduced that the right one is the one with the antidote.

This is ludicrous, but also what must be the starting point in debating on this subject. For if they say that the presence of phages proves that the hadith is correct, then pointing out that phages are not limited to any one wing, right or left, immediately proves the falsehood in the hadiths.

They make erroneous assumptions

A. They assume that bacteriophages are antidotal to bacteria. Bacteriophages cause lysis of their bacterial hosts in the final stage of infection – thereby releasing new phage particles to infect other bacterial cells in the population. However, in the natural environment, this state is equilibrial – meaning that only a small proportion of bacterial cells is infected at any one time. Just like only a small proportion of humans is ever infected with the flu virus at any one time (except in a pandemic).

B. They assume that flies must carry the antidote to the pathogens they carry.

… from the perspective of logic, if the fly did not carry some sort of protection in the form of an antidote or immunity, it would perish from its own poisonous burden and there would be no fly left in the world.

As far as we know, flies do not succumb to human pathogens – they are merely carriers. This shows that those who make these claims do not understand pathogenesis. Flies do not succumb to human diseases.

The way it works is like this:

Fly lands on feces or rotting carcass – gets traces of feces or rotting carcass on itself.
Fly lands on human food – drops traces of feces or rotting carcass on human food.
Fly flies away – human consumes contaminated food and gets sick.
Fly continues on with its life, free to repeat the cycle again.

C. They falsely assume relations that do not exist.

The existence of similar bacteria-killing mechanisms in two bacteriophages suggests that antibiotics for human infections might be designed on the basis of these cell wall-destroying proteins. Science 292 (June 2001) p. 2326-2329.

The ability to design antibiotics that might utilize bacteriophage infection pathways does not prove that phages are antidotal to bacteria. Antibiotics are not phages. Further, these antibiotics are likely to be ‘artificial’ and do not reflect the natural state of fly-human disease interactions.

They make patently erroneous statements

Only in modern times was it discovered that the common fly carried parasitic pathogens for many diseases including malaria, typhoid fever, cholera, and others. It was also discovered that the fly carried parasitic bacteriophagic fungi capable of fighting the germs of all these diseases.

There are two errors here:

A. The common fly does not carry malaria – that is carried by and transmitted exclusively through the bites of Anopheles mosquitoes.^[1]

B. There is no such thing as bacteriophagic fungi. This term may sound impressive to non-scientists, but bacteriophages are viruses and fungi are simply fungi.

They quote scientific articles that contain errors

These fly microbiota are bacteriophagic or "germ-eating". Bacteriophages are viruses of viruses. They attack viruses and bacteria. They can be selected and bred to kill specific organisms. The viruses infect a bacterium, replicate and fill the bacterial cell with new copies of the virus, and then break through the bacterium's cell wall, causing it to burst. The existence of similar bacteria-killing mechanisms in two bacteriophages suggests that antibiotics for human infections might be designed on the basis of these cell wall-destroying proteins. Science 292 (June 2001) p. 2326-2329.

A. Bacteriophages do not attack other viruses.

B. Not all bacteriophages encode cell-wall destroying proteins to lyse host cells.

They misinterpret scientific facts

Gnotobiotic [=germ-free] insects (Greenberg et al, 1970) were used to provide evidence of the bacterial pathogen-suppressing ability of the microbiota of Musca domestica [houseflies] .... most relationships between insects and their microbiota remain undefined. Studies with gnotobiotic locusts suggest that the microbiota confers previously unexpected benefits for the insect host.

This basically says that the microbiota of insects protect them from their (i.e. insect) pathogens. It does not say anything about human pathogens carried by insects.

An article in Vol. 43 of the Rockefeller Foundation's Journal of Experimental Medicine (1927) p. 1037 stated: The flies were given some of the cultured microbes for certain diseases. After some time the germs died and no trace was left of them while a germ-devouring substance formed in the flies - bacteriophages. If a saline solution were to be obtained from these flies it would contain bacteriophages able to suppress four kinds of disease-inducing germs and to benefit immunity against four other kinds. Cited in `Abd Allah al-Qusami, Mushkilat al-Ahadith al-Nabawiyya wa-Bayanuha (p. 42).

This has just proven the existence of bacteriophages. What it has not proven is whether these bacteriophages protect humans against human pathogens carried by flies.

They make extension of claims

The fly microbiota were described as "longitudinal yeast cells living as parasites inside their bellies. These yeast cells, in order to perpetuate their life cycle, protrude through certain respiratory tubules of the fly. If the fly is dipped in a liquid, the cells burst into the fluid and the content of those cells is an antidote for the pathogens which the fly carries." Cf. Footnote in the Translation of the Meanings of Sahih al-Bukhari by Muhammad Muhsin Khan (7:372, Book 76 Medicine, Chapter 58, Hadith 5782).

Now it is not only phages on the right wing, but the yeast cells inside fly stomachs and respiratory tubules. We assume it is the yeast antibiotics they are referring to. The presence of tiny amounts of antibiotics (produced by fungi) do not protect humans from enteric diseases. Apologists are confused about antibiotics – they do not understand how antibiotics work. Dosage is important. Modern antibiotics are artificial and highly purified. Treatment of bacterial infections involves ‘massive’ doses of purified antibiotics that are not found in the natural environment.

They confuse the use of bacteriophage

Bacteriophagic medicine was available in the West before the forties but was discontinued when penicillin and other "miracle antibiotics" came out. Bacteriophages continued to flourish in Eastern Europe as an over-the-counter medicine. The "O1-phage" has been used for diagnosis of all Salmonella types while the prophylaxis of Shigella dysentery was conducted with the help of phages. Annales Immunologiae Hungaricae No. 9 (1966) in German.

A. The O1-phage is used for typing (i.e. diagnosing) Salmonella infections, not treating it.

B. Bacteriophage therapy was subsumed by antibiotic therapy in the 1940s because it was largely ineffective. Before antibiotics, physicians were desperate for cures – they would try anything, even bacteriophage therapy – but that does not prove bacteriophage therapy works. In any event, one would need massive doses of phages to treat each case – which does not occur in the natural environment. A fly dipping its right wing, left wing, or its entire body, will not be sufficient.

They do not understand what they purport to be proof

However, researchers in eastern Europe, including the former Soviet Union, continued their studies of the potential healing properties of phages. And now that strains of bacteria resistant to standard antibiotics are on the rise, the idea of phage therapy has been getting more attention in the worldwide medical community. Several biotechnology companies have been formed in the U.S. to develop bacteriophage-based treatments - many of them drawing on the expertise of researchers from eastern Europe." http://www.sciencefriday.com/pages/2000/Jul/hour1_072100.html

A. This article they quote and link to highlights one of the main limitations of bacteriophages in therapeutics, i.e. it is rapidly taken up by the human body and destroyed in human spleen cells. Therefore, even when a fly should carry bacteriophages, normal human physiology precludes these phages from acting as antidotes.

B. Even if some biotechnology companies want to develop bacteriophage-based treatments, it does not prove the hadith to be correct. These bacteriophage-based treatments involve the use of genetic engineering and other advanced scientific techniques to utilize bacteriophage pathogenesis for the treatment of human diseases. Naturally-occurring bacteriophages are useless for this purpose.

They ignore non-bacterial enteric diseases

Even if the wings of flies were to provide humans with an antidote to bacterial diseases, they could possibly infect humans with another non-bacterial disease. Flies also spread pinworm, tapeworm, viral gastroenteritis, amebic dysentery, giardia enteritis, and enteric hepatitis. Bacteriophages and fungi are totally ineffective against these diseases.

Conclusion

The scientific evidence does not support the veracity of the fly wing hadith for the following reasons:

1. Contrary to their innovative interpretations of relevant hadith, bacteriophages are not limited to any specific wing of the fly.

2. Contrary to their innovative interpretations of relevant hadith, bacteriophages in the natural state and concentration are not antidotal to bacterial diseases, particularly for temperate or lysogenic phages.

3. Bacteriophages are ineffective against non-bacterial diseases carried by flies, meaning even if the wings were to provide you with an antidote to bacterial diseases, they would possibly infect you with another non-bacterial disease (i.e. dipping a fly into your drink is not good advice).

4. Phage therapy is not a generally-accepted medical therapy at present because it is largely ineffective and requires large quantities of purified, possibly genetically-engineered, phages not present in the natural condition.

This page is featured in the core article, Islam and Science which serves as a starting point for anyone wishing to learn more about this topic