Text & Photos by Tommy Kirkland
One of the reasons drought enhances the spread of EHD is that all wildlife and insects congregate over limited water sources. When deer gather at watering holes, the risk of transmitting disease increases. Even though EHD is not transmitted from deer to deer, other infections, particularly parasites, can be spread as well. This is why it is imperative to control and prevent high deer densities.
-- Last year in 2007, a large outbreak of EHD (Epizootic Hemorrhagic Disease) unfolded throughout the country - causing the deaths of several thousand plus whitetails. From the Carolinas, Georgia, Alabama, Texas and on up into Tennessee, Indiana, Illinois, Ohio, and Maryland as well as other states, hemorrhagic disease was intense and widespread.
Although EHD kills a certain number of deer each year and is usually sporadic, the summer of 2007 was dramatic. Scores of outdoorsmen and landowners continue to discover the remains of many whitetails. Wildlife biologists with state agencies reported that 2007 was one of the worst years since 2002's EHD epidemic.
Yet what exactly is EHD and how does it affect whitetails? Though there are certain viruses in the EHD classification, the two most common types afflicting whitetails are referred to EHD and BT, also known as blue tongue. Both are known to cause serious internal bleeding.
These diseases are transmitted to deer by small biting flies commonly called gnats, or no-see-ums. EHD usually takes place in the summer from late July and August and can even extend into October until a cold snap suppresses the flying insects. Also, the more abundant the no-see-ums are, the higher the risk of EHD infections along with bucks bachelor grouping and females congregating in the summer. Extreme environmental conditions, (see Buckmasters Online article "The Drought of 2007"), can also heighten the likelihood of large EHD outbreaks.
The disease has been around since the 1950s; and although outbreaks are common in the Midwest and Northeastern states, it is mainly associated with whitetails in the Southeast. The indications that EHD is present can vary - especially if some whitetails build up a resistance to the virus over time. Nevertheless, the most common and visible symptoms of EHD are a swollen head, neck and tongue. Whitetails may also show signs of breathing problems.
Depending on a herd's overall health and duration of infection, whitetails can display EHD signs within just a few days after being infected. For others, it could be weeks before loss of appetite and sluggishness takes place. Deer may also release saliva and mucous from their nasal passages more so than usual and blood can be seen to some degree. Yet the real evidence for EHD is internal with hemorrhages. Ulcers can also manifest in the deer's mouth; and once the disease reaches a serious stage, the animal's hooves will reveal deformities and peeling.
In most cases of EHD, whitetail carcasses can be found near water sources and shaded woodlots near water. Evidence of EHD includes a swollen face and tongue, blood in the saliva, and cracked or split hooves.
If EHD is suspected in a herd, the only way to really know is to have a biologist or a wildlife veterinarian examine the carcass. Many other deer diseases can cause minor but similar symptoms to EHD, simply because the disease affects each deer differently from mild to severe. Some whitetails build-up a resistance to it - showing little to no visible symptoms at all.
Even so, the most common warning of EHD is a sudden loss of deer on a property or lease. Within just a few weeks, the visibility of whitetails can diminish. The infected animals will seek water, and can be found near water sources. Yet if predators such as coyotes roam the area; then determining the actual cause of death could be difficult. Coyotes are quick to scavenge a deer carcass - at times just leaving a few bones.
Can EHD negatively affect a deer population? Scientific studies show that EHD usually accounts for roughly a 25-percent mortality rate of a localized deer herd, but on rare occasions, half of the deer population can succumb to the disease. EHD tends to be more prevalent in high deer densities but is also found in areas with low deer densities.
To date, humans are not at risk for contracting EHD, even after consuming venison. However, most state agencies recommend not eating infected deer due to various bacterial infections secondary to the disease. Therefore, if you suspect that a deer you harvested has EHD, by all means contact your local state wildlife agency for assistance.
Besides EHD, summertime intensifies a host of other parasitic problems - most of which are only a nuisance for the deer themselves. The most common and obvious irritations for the whitetails are nasal bot flies which deposit their larvae in the nasal passages of whitetails. These pests cause the deer to sneeze or broadcast a false snort periodically.
During the summer months, whitetails are also afflicted with other problems. More common are skin tumors, known as papillomas or fibromas. This ailment is not serious and does not affect the venison.
Whitetails are also exposed to various tapeworm infections. They usually show up in the liver and abdominal areas and pose no threat to humans or the deer. However, due to consuming low quality nutrition combined with old age, a whitetail cannot maintain a normal body weight because consumed nutrition is feeding the tapeworm as well.
Deer also develop skin tumors that give a warlike growth appearance. They are known as fibromas and do not affect the venison for human consumption.
Despite the many diseases and parasitic infections that whitetails can experience, deer have developed an amazing ability to adapt and survive during the summer. This time also sets the stage for a white-tailed buck's process of antler growth, the next installment here at Buckmasters.com.
-- Tommy Kirkland
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