Saturday, September 28, 2013

Ancient Parasites of Puppies in Egypt

Researchers showing the infested ear of the mummified dog.
A really great article came out in the International Journal of Paleopathology last month.  It was entitled, "The dog mummy, the ticks and the louse fly: Archaeological report of severe ectoparasitosis in Ancient Egypt".  In this paper, a site in El Deir, Egypt was excavated between 2010 and 2011.  There were hundreds of mummified dogs found at the site. One of the dog mummies was unique from the others...it had ectoparasites!
This dog represents the first real evidence of canine ectoparasitism in Ancient Egypt. Researchers found a great load of ticks and a louse fly still attached to the ears and coat of the mummified pup.  These parasites may have been vectors for a variety of diseases that could have lead to the early passing of the young dog.


Mummified dog's ear infested with ticks.

People have suspected that such diseases existed in antiquity based on the writings of early Greek and Latin scholars.  Aristotle called do parasites kunorhaistes, a.k.a "dog destroyer".  Homer described Ulysses' dog as being infested by the same.  Pliny the Elder also described ticks that burdened dogs of his day saying:

"There is an animal...that always lives with its head fixed in the blood of a host, and consequently goes on swelling, as it is the only animal that has no vent for its food; with gorging to excess it bursts, so dying of its very nutriment.  This creature...occurs frequently in oxen and occasionally in dogs in which all creatures breed."
 
The oldest record of ticks exists in a piece of art dating back to Ancient Egypt.  This art depicts a "hyena-like animal" with ticks in its ear and dates to the 15th century B. C.  The piece is currently housed in the Metropolitain Museum of Art in New York.  This new paper represents the first time that anyone has actually found hard evidence that such ectoparasites did, in fact, exist. 

Piece from the Tomb of Intef, New Kingdom, Thebes, Upper Egypt.
Okay, parasite details!  Parasite details!  The ectoparasites found fell into two types.  The first was the brown dog tick, Rhipicephalus sanguineus, a type of hard tick found commonly all over the world, but especially in warm climates.  The second type was the louse fly, Hippobosca longipennis, a type of hippoboscid fly native to Africa, Asia, and the Middle East. 


There were 61 individual specimens of the hard tick recovered from the dog mummy with 38% of them pulled out of the inner ear alone.  This indicates that the 4-5 month old puppy may have suffered from problems like anemia or tick-borne pathogens.  Only a single louse fly was found on the coat of the animal.

The researchers also found the puparia of flies belonging in the families of Calliphoridae and Sarcophagidae.  The presence of these puparia could have been a source of myiasis (the infection of a live mammal with the larvae  of these flies).  However, the presence of these flies may also have invaded the dog mummies post-mortem. (Which I, personally, feel is more likely.)

Moral of the Story
It is pretty exciting to find solid proof of canine parasitism dating back to Ancient Egypt.  That being said, I have to wonder whether or not a parasitologist was a part of this research.  I have a few questions that come to mind about this amazing ectoparasite discovery.  First and foremost, why the hell were the ticks still attached to the dog?  Usually, when a tick's host dies, the ticks...to the best of my limited knowledge...abandon ship and go off questing for another host with their little jointed appendages reaching out for love.  Yet, here we find amazingly well-preserved ticks that, quite literally, had a death grip on the ears of these dogs.  WHY?  The authors proposed that the ticks were still there because their hypostomes have been known to sort of get stuck from time to time and stay attached to their hosts.  (They did not cite this assertion, so I'm not sure where that has been reported.)  Sure, the ticks might not pop off immediately, but I doubt they would hang on to the point that they would die and become mummified along with their host.  I'm thinking there had to be something else going on here!  The authors also proposed that perhaps the parasites were vectors for diseases that led to the early demise of the dog.  Though completely plausible, I'm not sure that I totally buy into this idea.  

Parasites and puparia collected
from dog mummies.
Another question that came to mind for me was the authors' theory that perhaps the puparia belonged to flies that had invaded their hosts' tissues while the hosts were still alive. I'm not really buying that one either.  I believe that it is far more likely that these puparia belonged to flies that laid eggs/larvae in their hosts post-mortem.  After hatching and molting, they would have pupated prior to some abrupt happenstance that preserved them before they could complete their life cycle.  (Although many of the puparia were fragments rather than whole puparia, indicating that many of the flies may have completed their life cycle without hindrance.)  It seems to me that perhaps the dog died in some way that killed the ticks and louse fly as quickly as it killed the dogs (perhaps a strong poison of some sort?) or possibly the dog became paralyzed (via ticks or from whatever caused the three vertebral dislocations I didn't mention earlier) and the owners entombed the dog thinking it was dead.   In either case, perhaps the dog's body was left exposed long enough for flesh flies and blow flies to invade its corpse.  Afterwards, the dog was placed in what I'm speculating may have been an anaerobic environment that could have halted the lives of the flies just after reaching their pupal stages.  This would be one explanation for the presence of these flies and arachnids found in these mummies.

My biological curiosities aside, it is very important that we can definitively say that the ectoparasitism of domesticated dogs dates back to the days of Ancient Egypt.  This is an incredible find in that it tells us that the host-parasite interactions found in modern canines are not all that different from those found thousands of years ago.  It is also interesting to note that the morphology of the brown dog tick hasn't changed much in all that time...I suppose if it ain't broke... This research will be helpful for those who are especially interested in the evolution of canine parasitism. Hooray for paleoparasitology!!!

2 comments:

  1. Agreed plain83!

    In other news, I spoke with some of my colleagues and learned that engorged ticks do tend to go down with the ship while ticks that have yet to attach at the time the host dies will hop off and look for a new host. I never realized engorged ticks would stay on, and apparently die on, a deceased host. That little tidbit makes this find make a little more sense to me than it did before, although I still think it's super awesome and important. :)

    ReplyDelete