Don’t Blame the Deer!
Many folks have been known to blame the deer for spreading Lyme Disease. We have to remember that ticks (the young ones anyway) are usually carried by mice & ground feeding birds, deer are actually poor hosts they are great for the adult tick for feeding & breeding & so can complete the life cycle, but without deer all that will happen is that these adults will seek other warm blooded animals perhaps in their starving state look for more humans & dogs to munch on. I hope that Ireland does not decide to do a mass culling of deer to control lyme cases, I think we have to look at the bigger picture.
One thing I loved seeing in the States is a deer station where insecticides (arachnacides) were rubbed onto rollers & as the deer fed their antlers picked up the stuff to kill the ticks. Others have used bedding for mice that was soaked in tick killing or repelling chemicals & they would carry it back to their nests hence controlling the ticks in the mouse community – I’d much rather see that than culling..
..Or maybe Prince Charles has it right, using sheep as tick mops with natural repellant http://www.timesonline.co.uk/tol/news/uk/scotland/article6946028.ece (link since broken however this site mentions using sheep as tick mops..
Sheep can also be used as ‘tick mops’ to reduce the number of blood-sucking, sheep ticks on a moor because they attract the ticks.
By regularly treating the sheep with pesticides, to kill off the ticks, they can be used to literally mop up ticks from the moor and greatly reduce their numbers.
The Michigan governenmet site had this to say:
The relationship between deer and the disease is complex. Deer show no symptoms of the disease. Deer may carry small numbers of the spirochete that causes Lyme disease but they are dead-end hosts for the bacterium. Deer cannot infect another animal directly and no deer hunter has acquired the disease from dressing out a deer. Infected ticks that drop from deer present little risk to humans or other animals since the ticks are now at the end of their life cycle and will not feed again. There is no evidence that humans can become infected by eating venison from an infected deer. In addition, the Lyme organism is killed by the high temperatures that would be reached when venison is cooked or smoked. Deer supply the tick that transmits the bacterium with a place to mate and provides a blood meal for the female tick prior to production of eggs. Research has shown that white-tailed deer are important to the reproductive success of the black-legged tick. In the absence of deer, this tick will opportunistically feed on other medium sized mammals and humans. As a management tool for Lyme Disease, there is still debate in the scientific community as to whether reducing the number of deer present in an area will effectively or dramatically reduce Lyme Disease “risk”.
Here is Lyme Docs’ latest blog about this:
“Bumper crop of ticks this year. Our dog came down with a lame paw and was diagnosed with Lyme disease. Family members have unfortunately had tick bites. (I know).We live in a zero-lot-line community with minimal grass, no deer – but -lots of rabbits. Our dog is always trying to dislocate my shoulders eager to pursue these critters.
The term “deer tick” is misleading. Deer, like us humans are incidental hosts. The animals feed, neck bent, in tick infested brush. Deer heads and necks covered with Ixodes is a testament to just how dense the population of ticks is. Not that deer are a necessary part of the equation. Any warm blooded animal (even us humans) can serve as the tertiary host for adult female maturation. In my case, rabbits are generally the final host.
The problem is the primary host: the white footed mouse. Newly hatched larvae take feed on mice having Borrelia swarming through their bodies (and co-infecting organisms) then morph into nymph forms which are the primary culprit for human transmission.
The 6 legged larvae become the 8 legged nymphs, well equipped for the job at hand. They can move very quickly andt hen lie still, perched for action, sniffing out the carbon dioxide and body heat of their next unwitting meal.
When we pull off an adult tick we don’t really know how many others smaller forms may have attacked us unseen. The issue of how long the tick needs to be in place in order to transmit Lyme disease may be a moot point since most tick bites are never seen.
Some have suggested that most of the ticks are not infected and that we need not worry so much. Informal data from Clongen labs indicates the infection rates may range from 30-70 percent depending on the time of year in our area.
Any effective prevention programs must focus on effective ways to kill the ticks and perhaps the mice if possible. Thinning out deer populations, as some have suggested, will be of no help.
As for my bunnies, their population does thin out – spring to fall – meals for predators like our fox. Unfornuately, the fox become the next host for the stubborn ticks.”
As usual with Lyme there is no easy answer but whilst we’re trying our best to raise awareness I would hate for a mass panic in the population & a call for mass culling of deer. If there’s anyway to control tick numbers through other means I would be delighted 😉
A message to hunters:
Visitors to the Deer Alliance HCAP Blog are invited to consider the contents of advisory information on LYME DISEASE set out in the letter below, and are urged to take the information on board when deerstalking, hillwalking or undertaking any activity likely to lead to exposure to Lyme Disease.
Re. Protecting against Lyme Disease when taking part in outdoor pursuits
I am writing to you on behalf to the South East Regional Zoonoses Committee. We are a multidisciplinary group of Human and Animal Health Professionals from the South East whose remit includes informing the public about diseases that can be passed between animals and humans.
Those affiliated with Deer Alliance Ireland are involved in outdoor pursuits and may be at risk of contracting Lyme disease because these activities.
Lyme disease, which is spread by tick bites, can, in a minority of cases, cause severe debilitating heart and nervous system disease. Recently the HSE Health Protection Surveillance Centre issued a warning to people who engage in out-door pursuits in the summer months -ramblers, campers, mountain-bikers and others who work or walk in forested or grassy areas -to be vigilant against tick bites. Ticks are tiny insect-like creatures that feed on the blood of mammals and birds and will also feed on humans. Ticks are more active and numerous in the summer months and protecting against tick bites protects against Lyme disease.
Tick bites can be prevented by:
• Wearing long trousers, long-sleeved shirt and shoes
• Using insect repellent
• Checking skin, hair and warm skin-folds (especially the neck and scalp of children) for ticks after a day out
• Removing any ticks and consulting with a GP if symptoms develop
• Using tick collars for pets (they can get Lyme disease) and inspecting them for (and removing) any ticks.
Only a minority of ticks carry infection. If a tick is removed within a few hours, the risk of infection is low. The entire tick, including any mouthparts which might break off, should be removed with a tweezers by gripping it close to the skin. The skin where the tick was found should be then washed with soap and water and the area checked over the next few weeks for swelling or redness. Anyone who develops symptoms should contact their GP and explain that they had been bitten by a tick.
Further important information on protecting against Lyme disease, an information leaflet and a poster are available at http://www.hpsc.ie/hpsc/A-Z/Vectorborne/LymeDisease/
We would urge you to encourage those affiliated with Deer Alliance Ireland to read this information and we suggest that a copy of the HPSC leaflet be included with your education material.
Dr. Sarah Doyle, MB MRCPI MPH MFPHMI, MCRN 19055
Consultant in Public Health Medicine,
Secretary to the South East Regional Zoonoses Committee,
Public Health Department,
24 January 2012