Tag: disease

Nasal Bots in White-tailed Deer

Nasal Bots in Deer

Most deer hunters that have harvested white-tailed deer have, unfortunately, found nasal bots. Nasal bots in deer are very common. At first glance, what a hunter encounters looks like a large maggot. And, that’s basically what a nasal bot is. They live in the cavities of the deer’s nose and mouth.

Nasal bots are the larvae of a specific kind of fly that belongs in the genus Cephenemyia. Deer biologists actually find them in a percentage of whitetail deer, particularly when a thorough examination of the head is conducted. From my experience, white-tailed deer in Texas are more likely to have nasals bots than to not have them.

What’s Up, Nasal Bot?

These bots are specific to members of the deer family, which also includes elk and mule deer in the United States. Nasal bots begin life when the adult fly lays a group of eggs around the nose or mouth of a deer. Next, the small larvae within these eggs are then released when the deer licks the eggs.

White-tailed deer often have nasal bots

The warm, wet saliva creates an environment that permits the “hatching” of the immature bots. These larvae then migrate to the nasal passages and occasionally into the sinuses. While there, they molt into larger stages of the maturing larvae.

The mature larvae then move to the deep cavities in the deer’s mouth called the retropharyngeal pouches. The fully matured bots then exit and pupate in the ground until emerging as adult flies. Then, they begin the life cycle all over again.

Are Nasal Bots in Deer A Problem?

To a white-tailed deer, nasal bots are typically only a minor nuisance. The bots do irritate the lining of the nasal passages and move about in the retropharyngeal pouches. In fact, most sneezing and coughing of deer is assumed to be the result of nasal bots. From a clinical perspective, the bots do not cause deer any harm. No sores, infection, nor other problems have been reported, even when the parasites are present in large numbers.

Deer hunters normally encounter nasal bots after the deer they harvested has begun to cool. After the deer dies, the body temperature falls and the bots begin to leave the nasal passages and oral pouches in search of a more suitable environment. These bots then exit through either the nose or mouth. Bots can also move in the wrong direction, or down the trachea (where it is usually warmer), and may appear to be in the body cavity of the deer, even though they are not.

Lastly, nasal bots in deer pose no disease threat to deer hunters. They do not harm the venison. Remember, nasal bots are only found in nasal passages and around the mouth of deer. Deer “infected” with these harmless parasites are safe for human consumption. However, I suspect many unknowing hunters have discarded deer carcasses after observing an ugly larvae crawl out of a deer’s nose.

Deer Warts or Tumors?

When deer hunters head out into the field they don’t usually think to themselves, “Man, I want to harvest a healthy deer.” But we all do, even though we don’t really think about it. So., what if you harvested a deer with warts? Most hunters would be a little concerned because, after all, warts are not normal on white-tailed deer.

Although injuries and diseases are some things hunters and property owners serious about deer management try to avoid having in their herds, it usually can not be avoided.

These “deer tumors”, which are more accurately wart-like growths, and are formally referred to as cutaneous fibromatosis. The virus that causes such growth on the skin can be transmitted between deer, at least experimentally.

Deer fibroma occurs occasionally in white-tailed deer living in North America. Although the ailment is not common, it not extremely rare either. The cutaneous growths can vary in diameter, but usually vary from about 1/4 inch to 4 inches in size.

These wart-like growths can be found growing by themselves or in clusters, typically on the front-end of an infected deer. The whitetail buck featured in the above photos has warts caused by cutaneous fibroma on the underside of his neck and face.

Although these tumor-looking growths are not believed to directly harm the deer, the presence of these warts could cause additional stress or points for additional injury on an animal.

From a hunting or deer management perspective there is little that can be done once a deer contracts fibroma. In some cases the infection may not even be noticeable, but as in the example above, the warts may be very obvious. The virus has been successfully spread under experimental conditions from deer to deer, but the chances of this happening in wild deer herds is unknown.