Deer and Lyme Disease, Research and News on the Relationship
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Summary: Deer are immune to Lyme disease and do not carry the diseases. If an infected tick bites a deer, the disease does not spread to other ticks that may bite the deer as it would if the tick bit a mouse. Reducing the number of deer may reduce the number of ticks, but because of the dilution effect, the result can be a higher percentage of remaining ticks with the disease since the ticks will choose other hosts that may be carriers of the disease. Deer also browse on the vegetation that provide tick habitat. While deer may provide a meal for the adult tick, research shows the risk of Lyme disease is statistically correlated to mice, chipmunks, and ground dwelling birds. Deer groom themselves, eliminating many ticks. A reference book.
Ecology of Infection Disease: A Special Report (On Lyme Disease) National Science Foundation
... Areas of patchy woods, which are very common in cities and suburban and rural areas, may have higher populations of Lyme-disease carrying ticks than forest fragments, which generally have fewer species than continuous habitat. This is because some species thrive in smaller places. White-footed mice, for example, are more abundant in forest fragments in some parts of the country, likely because fewer predators and competitors remain there. These mice are particularly abundant in patches smaller than about five acres, which could spell trouble for people living nearby: the mice are the main carriers of Lyme disease-causing bacteria ...
"Our results suggest that efforts to reduce the risk of Lyme disease should be directed toward decreasing fragmentation of deciduous forests of the northeastern United States, particularly in areas with a high incidence of Lyme disease ...The creation of forest fragments smaller than five acres should especially be avoided."
Don't blame deer because ticks carry disease June 19, 2017 Maine, The Forecaster
"... Research in New England shows that when deer abundance is reduced, adult ticks crowd onto the remaining deer, so that there is little if any decline in total ticks on deer... Our studies in upstate New York show that Lyme disease risk is correlated with abundance of mice, but not with abundance of deer. Deer do not infect the ticks with Lyme disease bacteria, but mice and chipmunks do..." [Dr. Richard Ostfeld, a director of The Tick Project www.tickproject.org]
An anti-Lyme disease vaccine for mice could help prevent human infections January 19, 2020 Connectictut, Medical Xpress
... Scientists at the Connecticut Agricultural Experiment Station recently finished a three-year study that provided vaccine-coated food pellets to mice in the backyards of 32 homes in Redding. In a recently published paper on the study, researchers reported a 26% drop in the number of Lyme disease-infected white-footed mice ...
Tick expert: Killing deer, keeping chickens won't cut Lyme risk in Fayetteville May 26, 2016 New York, Syracuse Post-Standard
... Felicia Keesing, a Bard College biology professor who has researched the distribution of ticks and Lyme disease since 1999, said culling some deer hasn't been shown clearly to cut the risk of Lyme in communities. She said many of the studies that indicate culling deer could help have been found to be unreliable....
Where foxes thrive, Lyme disease doesn't September 10, 2012 New York, Poughkeepsie Journal
... Taal Levi has studied environments from Brazil to Alaska ... His statistical analysis showed little correlation between the prevalence of deer and the incidence of Lyme. If that were the case, Levi said, “then why is Lyme disease so relatively rare in Western New York when deer are more abundant than in places here that have lots of Lyme disease?” ...Levi used statistical data to show that as fox populations went down, Lyme went up. The statistical connection between Lyme and other species wasn’t as consistent. The study was published in the Proceedings of the National Academy of Sciences in June...
Lyme study highlights why small mammals spread disease September 23, 2014 New York, Poughkeepsie Journal
... The research also undercuts a misconception that Lyme disease is spread primarily by ticks that feed on deer, a notion that has incorrectly popularized the label "deer tick" for the black-legged tick that can be infected by other mammalian hosts... large litters of mice, shrews and chipmunks correspond with the increased chance that a tick will pick up Lyme disease and two malaria-like diseases... [read the article in PLOS ONE]
State of New Hampshire Tickborne Disease Prevention Plan [PDF] March 31, 2015
... For the years 2008 and 2012, NH had the highest incidence rate of Lyme disease in the US.... Because NH is near the northern limit of white-tailed deer range it is known to have one of the lowest density deer herds in the eastern US ... The main, and shared, reservoir host for the four tickborne diseases known to be transmitted in NH is the white footed mouse. Chipmunks, shrews, voles and birds, including the American Robin, have also been identified as reservoirs for Lyme disease, although are of lesser importance. Wild
rodents have been identified as possible reservoirs for anaplasmosis and babesiosis; woodchucks, squirrels and the white footed mouse are the three known reservoirs for Powassan virus...
Co-Infections Possible from Tick Bites June 24, 2014 Massachusetts, Boston
... New to this study, said co-author Felicia Keesing, is that the small mammals the ticks feed on also carry multiple infections... Ticks resort to feeding exclusively on small mammals when there aren’t larger animals, like raccoons or deer, to feast upon. ... scientists at Bard College, Sarah Lawrence College and the Cary Institute of Ecosystem Studies...
Have deer gotten a false rap for Lyme disease? August 3, 2012 Earthwise [includes pictures and podcast]
... While deer host lots of ticks, so do other vertebrates, including raccoons, skunks, and white-footed mice. Eliminate deer, and ticks will feed on other hosts. Also, while deer don’t transmit the Lyme bacterium to ticks—the smaller mammals do. Rick Ostfeld, a senior scientist at the Cary Institute of Ecosystem Studies, has written a book on Lyme disease ecology…
Help Stop the Spread of Lyme Disease and Kill Deer Ticks With Damminix Tick Tubes August 22, 2013 Massachusetts, Comtex
... "Homeowners trying to kill ticks in their own yards need to target the rodents that carry the Lyme disease bacteria," says the CDC's Division of Vector-Borne Diseases Director Lyle Petersen in its recent report. That's how Tick Tubes target deer ticks. Developed at the Harvard School of Public Health, Damminix relies on the natural nesting instincts of rodents that carry Lyme disease and is the only rodent-targeting deer tick control solution on the market today. "Historically, people focused on deer as the culprit, but it's mice that spread Lyme disease," says Damminix Company Director Ariana Ganak. "When deer ticks hatch, they are disease free. Immature ticks feed on mice twice a year, and when they bite the infected mouse they become carriers of Lyme and pass it on to the unsuspecting general public. At long last people are becoming aware that mice are the real cause of this public health epidemic ...
Spritzing deer with tick insecticide is one way to fight Lyme disease September 1, 2013 New Hampshire, Nashua Telegraph
... the black-legged tick picks up the bacteria – a spirochete, to get technical – as a larva from the blood of the white-footed mouse, which carries the bacteria. ... They aren’t called “deer ticks” anymore ... even if every deer in New Hampshire became tick-free, we could still get Lyme from ticks via the white-footed mouse... the population of white-footed mice has exploded ... A variant of the deer feeding station idea is available for ticks: cardboard tubes filled with cotton balls treated with permethrin, a tick insecticide. Mice take the cotton back to their nests as building material, and it kills the ticks...
Forest Journal: Winter in New Hampshire a time for survival of the fittest January 18, 2014 New Hampshire, Union Leader
... Deer don't experience severe winter tick infestations. They tend to groom off questing winter ticks in autumn...Overwintering deer ticks may be reduced by extreme cold. That good news translates into a reduction in future rates of human Lyme disease...
East Hampton, Deer in Town Sights July 5, 2012 New York, East Hampton Star
... As for Lyme disease, the Group for Wildlife suggests that the town do more to educate the public about how to avoid tick bites and to prohibit the hunting of turkeys, which eat immature ticks. Because Lyme disease is also spread by ticks that feed on the white-footed mouse, the report says, “it’s unlikely that any reduction of deer populations can alleviate the disease.” ... if deer were eliminated, the ticks would feed on other animals ... two recent studies show that “four-poster” stations, where deer are exposed to tick-killing chemicals, reduced ticks by 69 to 100 percent....
Hunting Isn’t the Answer to Animal “Pests” November 27, 2013, Time
... Efforts to reduce Lyme disease with deer hunting are ineffective because the ticks feed on a wide variety of host species ... The only places where hunting is effective are in isolated areas—islands and peninsulas–where the ticks have few alternate hosts. To reduce the incidence of Lyme disease in humans on the mainland, the number of ticks needs to be reduced, not the number of deer. A 2011 study published in Public Health Reports found that a tick-killing device led to a reduction in the incidence of Lyme disease in humans in the area, while deer hunting “did not show a clear decreasing trend.” ...
The Rocky Mountains Have Ticks. Scientists Want To Know What Viruses They're Carrying April 29, 2018 Colorado, KUNC
... Researchers in other parts of the country have noticed that when deer populations drop, Buttke says, “the following year and sometimes the next year we have a really, really high number of ticks looking for blood meal hosts.” Instead of biting deer, they turn to people. Buttke says it’s all speculation whether chronic wasting could lead to a temporary spike in tick-borne disease...
Tick expert: Killing deer, keeping chickens won't cut Lyme risk in Fayetteville May 26, 2016 New York Syracuse.com
... Felicia Keesing, a Bard College biology professor who has researched the distribution of ticks and Lyme disease since 1999, said culling some deer hasn't been shown clearly to cut the risk of Lyme in communities. She said many of the studies that indicate culling deer could help have been found to be unreliable...
Missing Foxes Fuel Lyme Disease Spread June 18, 2012 LiveScience.com
Researchers used to think the increases were due to increasing deer populations ,,, However, the new data show these increases were independent of deer population levels... "Increases in Lyme disease in the Northeastern and Midwestern United States over the past three decades are frequently uncorrelated with deer abundance and instead coincide with a range-wide decline of a key small-mammal predator, the red fox, likely due to expansion of coyote populations,"... in the journal Proceedings of the National Academy of Sciences (June 18, 2012 article).
Increase in Lyme disease cases might have a coyote connection July 8, 2012 Michigan, Detroit Free Press
... Increases in the deer population have been blamed for the explosion of Lyme disease cases, but changes in the numbers of foxes and coyotes -- and what they eat -- actually might be responsible, according to a study published late last month. ... As coyotes have expanded in numbers and range, the new study suggests, they interfere with the important role served by foxes: to suppress rodent hosts of Lyme disease, especially around human habitation.
Council Talks Deer Management, Chevy Chase Program Deemed A Success? February 28, 2013 Maryland, Bethesda Now
... County data shows the deer management program racked up 5,598 deer kills during the 2012-2013 seasons, 5,571 in 2011-2012, 5,969 in 2010-2011 and 5,599 in 2009-2010. Despite those totals... In the case of Lyme disease, which some dispute is related to deer overpopulation, the numbers have also remained steady. There were 297 confirmed and probably cases of Lyme disease in the county in 2011 and 296 in 2010, the two most recent years that those statistics were available.
Lyme Disease: Habitat Fragmentation and the Abundance of White-tailed Deer L Chavez - 2017
... The results of the linear regressions that were ran did not support the hypothesis that in areas with increased cropland acreage there would be a higher population of white-tailed deer which would result in more reported cases of Lyme disease...
Surprise Culprits of Lyme Disease Boom June 18, 2012 Discovery News
Deer are not to blame for rising rates of Lyme disease ... Foxes don’t spread Lyme disease directly. Instead, they cull populations of small mammals, which are responsible for the bulk of infectious ticks. Where foxes are thriving, the risk of disease drops. But when fox numbers fall – often because coyotes move in, small mammal populations surge and Lyme disease flourishes.
Killing deer is no solution [to Lyme Disease] September 17, 2013 Connecticut, The Advocate, Laura Simon
Preventing Lyme disease is a vital goal, but killing deer isn't a solution ... Even when deer numbers are drastically lowered, ticks have no trouble finding other hosts and reproducing merrily.... Mice and chipmunks are important hosts for the immature stages of the tick, and popular songbirds bring ticks to new areas... National health authorities, such as the Centers for Disease Control and World Health Authority, as well as Connecticut State Health Department, are not calling for increased hunting because it will not effectively reduce human disease risk...
Predators, Prey and Lyme Disease June 18, 2012 New York Times (blog)
... While people used to blame deer for the spread of Lyme disease, Dr. Levi said that scientific evidence has indicated that deer probably aren’t significant transmitters of B. burgdorferi bacteria because their systems tend to quickly flush it out. ... models showed higher numbers of Lyme disease cases in places where there are fewer foxes. They detected no significant relationship between numbers of deer and numbers of Lyme disease cases.
Deer, predators, and the emergence of Lyme disease Proceedings of the National Academy of Science. June 18, 2012. Taal Levi, A. Marm Kilpatrick, Marc Mangel, and Christopher C. Wilmers
Lyme disease is the most prevalent vector-borne disease in North America, and both the annual incidence and geographic range are increasing. The emergence of Lyme disease has been attributed to a century-long recovery of deer, an important reproductive host for adult ticks. However, a growing body of evidence suggests that Lyme disease risk may now be more dynamically linked to fluctuations in the abundance of small-mammal hosts that are thought to infect the majority of ticks. The continuing and rapid increase in Lyme disease over the past two decades, long after the recolonization of deer, suggests that other factors, including changes in the ecology of small-mammal hosts may be responsible for the continuing emergence of Lyme disease. We present a theoretical model that illustrates how reductions in small-mammal predators can sharply increase Lyme disease risk. We then show that increases in Lyme disease in the northeastern and midwestern United States over the past three decades are frequently uncorrelated with deer abundance and instead coincide with a range-wide decline of a key small-mammal predator, the red fox, likely due to expansion of coyote populations. Further, across four states we find poor spatial correlation between deer abundance and Lyme disease incidence, but coyote abundance and fox rarity effectively predict the spatial distribution of Lyme disease in New York. These results suggest that changes in predator communities may have cascading impacts that facilitate the emergence of zoonotic diseases, the vast majority of which rely on hosts that occupy low trophic levels.
Climate, Deer, Rodents, and Acorns as Determinants of Variation in Lyme-Disease Risk Ostfeld RS, Canham CD, Oggenfuss K, Winchcombe RJ, Keesing F (2006) Climate, Deer, Rodents, and Acorns as Determinants of Variation in Lyme-Disease Risk. PLoS Biol 4(6): e145. doi:10.1371/journal.pbio.0040145
Indices of deer abundance had no predictive power, and precipitation in the current year and temperature in the prior year had only weak effects on entomological risk. The strongest predictors of a current year's risk were the prior year's abundance of mice and chipmunks and abundance of acorns 2 y previously. In no case did inclusion of deer or climate variables improve the predictive power of models based on rodents, acorns, or both. We conclude that interannual variation in entomological risk of exposure to Lyme disease is correlated positively with prior abundance of key hosts for the immature stages of the tick vector and with critical food resources for those hosts.
Biodiversity and Disease Risk: The Case of Lyme Disease Richard S. Ostfeld and Felicia Keesing
Conservation Biology Vol. 14, No. 3 (Jun., 2000), pp. 722-728
"A positive correlation between Lyme disease per capita and species richness of ground dwelling birds . . ."
Full Abstract: Utilitarian arguments concerning the value of biodiversity often include the benefits of animals, plants, and microbes as sources of medicines and as laboratory models of disease. The concept that species diversity per se may influence risk of exposure to disease has not been well developed, however. We present a conceptual model of how high species richness and evenness in communities of terrestrial vertebrates may reduce risk of exposure to Lyme disease, a spirochetal (Borrelia burgdorferi) disease transmitted by ixodid tick vectors. Many ticks never become infected because some hosts are highly inefficient at transmitting spirochete infections to feeding ti cks. In North America, the most competent reservoir host for the Lyme disease agent is the white-footed mouse (Peromyscus leucopus), a species that is widespread and locally abundant. We suggest that increases in species diversity within host communities may dilute the power of white-footed mice to infect ticks by causing more ticks to feed on inefficient disease reservoirs. High species diversity therefore is expected to result in lower prevalence of infection in ticks and consequently in lower risk of human exposure to Lyme disease. Analyses of states and multistate regions along the east coast of the United States demonstrated significant negative correlations between species richness of terrestrial small mammals (orders Rodentia, Insectivora, and Lagomorpha), a key group of hosts for ticks, and per capita numbers of reported Lyme disease cases, which supports our "dilution effect" hypothesis. We contrasted these findings to what might be expected when vectors acquire disease agents efficiently from many hosts, in which case infection prevalence of ticks may increase with increasing diversity hosts. A positive correlation between per capita Lyme disease cases and species richness of ground-dwelling birds supported this hypothesis, which we call the "rescue effect." The reservoir competence of hosts within vertebrate communities and the degree of specialization by ticks on particular hosts will strongly influence the relationship between species diversity and the risk of exposure to the many vector-borne diseases that plague humans.
Dilution Effect, "the scientific evidence as I’ve reviewed it, without any preconceived notion or political agenda or any other agenda, does not support the notion that tick numbers and Lyme disease risk are strongly correlated with deer numbers, and the data do not suggest that if you manage deer by hunting, you’ll reduce the number of Lyme cases.” Dr. Richard S. Ostfeld Disease Ecologist Ph.D., 1985, University of California. Buy the book on Amazon: Lyme Disease: The Ecology of a Complex System
Acorns And Mice Driving Unusual Lyme Disease Risks (ICEID 2) March 14, 2012, Wired News
Dr. Richard S. Ostfeld of the Cary Institute of Ecosystem Studies in Millbrook, New York, explained .. Mice also can survive in much smaller areas than the larger animals, chiefly deer, that are usually blamed for perpetuating Lyme, Ostfeld pointed out. In sampling of “forest fragments” sliced up by development in three northeastern states, his team has not found a parcel in which mice did not thrive. Larger parcels with more balanced ecosystems, with natural mouse predators and larger mammals, actually tend to have lower Lyme density ...
White-tailed deer live throughout Minnesota, but blacklegged ticks are not found everywhere that deer live
From Michigan Department of Natural Resources (Lyme disease): 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".
Duke Forest, Our illogical war on deer February 9, 2013 North Carolina, The Durham News, Karin Yates
... According to John Rohm of the Virginia Department of Game and Inland Fisheries, “Reducing deer density by X will not = X percentage reduction in Lyme disease cases. ... Deer should not be blamed for the current Lyme disease situation. Integrated pest management would be more effective than focusing solely on deer.”
Deer ticks thriving in Ohio December 3, 2013 StarBeacon.com
... “Migratory birds probably brought them to Ohio from Pennsylvania,” Needham said [Glen Needham, Ph. D., a deer tick expert and associate professor emeritus at Ohio State University] ... “Deer ticks will feed on anything despite their name,” ..
Studies confirm lizards fight Lyme disease May 30, 2015 California, Tehachapi News
... Western Fence Lizards, more commonly known as “Bluebellies,” ... Bluebellies eat ticks, which reduces the numbers of these parasites, but they also do something more extraordinary: a protein in the blood of Western Fence Lizards kills the Lyme disease bacterium in ticks that feed on the lizards ... Professor Jeff Burkhart of the University of La Verne ...
Explanation for Chronic Lyme Disease
Does this new study put an end to the chronic Lyme Disease controversy? Allentown Morning Call November 16, 2012
... It's not one stubborn infection that is making them ill, states a study released this week by the New England Journal of Medicine, but multiple new infections. Researchers at the University of Pennsylvania and New York Medical College studied 17 patients, who had the classic erythema migrans rash associated with Lyme disease, more than once in a span of 20 years. They analyzed the genetic makeup of the Lyme-causing bacteria in those who had been sick several times. Each time, they were infected by different strains of the bacteria, ruling out relapses.
Crucial Player For Lyme Disease Transmission Identified Decenber 21, 2013 RedOrbit
... Borrelia burgdorferi, the bacterium that causes Lyme disease, hitchhikes in ticks for dissemination to mammalian hosts–including humans. An article in the 19 December issue of PLOS Pathogens identifies HrpA, an RNA helicase, as a crucial player in the transmission from ticks to mammals... The authors say, “We now know that HrpA is involved in both parts of the B. burgdorferi lifecycle: animal infection and tick transmission, making it a very important protein in B. burgdorferi gene regulation and establishing gene regulation through an RNA helicase as an important regulatory pathway in the Lyme spirochete.”
Other Motives for the Lyme Disease Hunts
Odgen Dunes, Deer Management Task Force Publishes Findings/Opinions July 12, 2012 Indiana, SaveOurDeer.Org
... Ogden Dunes has not come to a consensus on whether there is an overabundance of deer in Ogden Dunes. But they have come to a consensus that killing deer will not eliminate the risk of Lyme Disease ... Despite this development, the threat of a deer cull within Town limits seems to remain. Why? ... It appears the real reason for the deer cull was never to protect young families from the risk of Lyme Disease. The Town government was using the fear factor of Lyme Disease to promote the idea of a deer cull when the real reason was to kill deer to keep them from eating the plants of prominent town residents...
Moose Die-Off Alarms Scientists October 14, 2013 New York, New York Times
... Across North America ... moose populations are in steep decline. And no one is sure why... Minnesota had two geographically separate moose populations. One of them has virtually disappeared since the 1990s, declining to fewer than 100 from 4,000... In New Hampshire, a longer fall with less snow has greatly increased the number of winter ticks, a devastating parasite... Deer are grooming animals, so they are able to keep tick numbers fairly low ...
Some Contradictory Results from Connecticut, based on Insular Enivronments
The Relationship Between Deer Density, Tick Abundance, and Human Cases of Lyme Disease in a Residential Community Journal of Medical Entomology, Howard J. Kilpatrick,1,2 Andrew M. Labonte,1 and Kirby C. Stafford, III3
... Reducing deer density to 5.1 deer per square kilometer resulted in a 76% reduction in tick abundance, 70% reduction in the entomological risk index, and 80% reduction in resident-reported cases of Lyme disease in the community from before to after a hunt was initiated... [This study shows a short term reduction but it was done one a pennisula with limited other animals. This relationship has only been documented on insular environments, not in open environments] ... from page 778 of the article: "The study area was the Mumford Cove (MC; 80.9-ha) community in Groton, CT. The number of occupied residences in MC year-round varied from 98 to 119 during the study. House lots were 0.61 ha each. MC was situated on a 1.9-km2 coastal peninsula bordered by Long Island Sound to the east and west. North of the peninsula was an 80-ha undeveloped state park closed to hunting and separated from MC by a
1.83-m-high chain-link fence. South of MC was the 105.9-ha residential community of Groton Long Point..."
Jamestown, Deer cull is counterproductive, says opponents September 11, 2014 Rhode Island, The Jamestown Press
... what about Monhegan Island off the coast of Maine? Professional sharpshooters eliminated the deer there in the 1990s, and the Lyme disappeared... Monhegan Island does not have mice. “It’s a whole different host ecology,” [Laura Simon] said. To compare Monhegan Island to Jamestown would be “like apples and bananas.” ...
The use of deer vehicle accidents as a proxy for measuring the degree of interaction between human and deer populations and its correlation with the incidence rate of Lyme disease. DH Wiznia, PJ Christos, AM LaBonte - Journal of environmental health, 2013
... The authors also examined the relationship between deer population density and human Lyme incidence rate. They analyzed data from Connecticut's Department of Environmental Protection and the Department of Public Health from 1999 through 2008 by deer management zone (DMZ) and town. For DVA incidence rate versus Lyme incidence rate for both DMZs and towns, most of the correlation coefficients computed yearly were moderate to strong and all of the p-values were significant. A weak correlation was observed between deer population density and Lyme disease incidence rate by DMZ. The authors propose DVAs as a proxy for measuring the interaction between coexisting populations of humans and deer.
Long-Term Effects of Berberis thunbergii (Ranunculales: Berberidaceae) Management on Ixodes scapularis (Acari: Ixodidae) Abundance and Borrelia burgdorferi SC Williams, MA Linske, JS Ward - Environmental Entomology, 2017
... Barberry management reduced B. burgdorferi-infected adult I. scapularis (BBIAIS) abundances (191/ha ± 64 SE) over 6 yr to statistically indifferent from that of no barberry areas (140/ha ± 47 SE; P = 0.080) and significantly less than intact barberry stands (458/ha ± 80 SE; P = 0.026). Over 9 yr, BBIAIS abundances in managed barberry remained lower than intact barberry stands (P = 0.037), but increased to be significantly greater than no barberry areas (P = 0.007) as cover increased over time. Longer-term data further document that Japanese barberry infestations are favorable habitat for I. scapularis...
Integrated Control of Nymphal Ixodes scapularis: Effectiveness of White-Tailed Deer Reduction, the Entomopathogenic Fungus Metarhizium anisopliae, and Fipronil … SC Williams, KC Stafford III, G Molaei, MA Linske - Vector-Borne and Zoonotic …, 2017
… Unfortunately, the efficacy of deer reduction as a tick management strategy in noninsular settings still remains unclear (Kugeler et al. 2016) ... questions related to the data analysis are presented in this link
Deer-Free Areas May Be Haven For Ticks, Disease
... This ScienceDaily article summarizes a Penn State Study: "This goes somewhat against conventional wisdom. When you remove deer, it does not always reduce the tick population," says Perkins. "If you were to exclude deer from hundreds of acres, tick numbers will fall. But in an area less than 2.5 acres, you are more likely to increase tick density and probably create tick-borne hotspots." ...
An Army Of Deer Ticks Carrying Lyme Disease Is Advancing And Here's Why It Will Only Get Worse August 7, 2018 HuffPost
... Rebecca Eisen, a federal CDC biologist who has studied climate’s influenceon Lyme, notes that deer ticks dominated the East Coast until the 1800s, when forests gave way to fields. The transition nearly wiped out the tick, which thrives in the leaf litter of oaks and maples. Since the 1990s, a decline in agriculture has brought back forests while suburbia has sprawled to the woods’ edges, creating the perfect habitat for tick hosts. Eisen suspects this changing land-use pattern is behind Lyme’s spread in mid-Atlantic states like Pennsylvania ...
Lake Michigan insights from island studies: the roles of chipmunks and coyotes in maintaining Ixodes scapularis and Borrelia burgdorferi in the absence of white-tailed deer
2021 Ticks and Tick-borne
... deer herd exists on North Manitou Island but not on South Manitou Island, where coyotes (Canis latrans) and hares (Sylvilagus lepus) are the dominant medium mammals... Our investigation demonstrated that alternative hosts could maintain a local population of blacklegged ticks and an enzootic cycle of the Lyme disease bacterium in the absence of white-tailed deer...
POPULATION AND COMMUNITY ECOLOGY,
Effects of Reduced Deer Density on the Abundance of Ixodes scapularis
(Acari: Ixodidae) and Lyme Disease Incidence in a Northern
New Jersey Endemic Area
ROBERT A. JORDAN,
TERRY L. SCHULZE, AND MARGARET B. JAHN
Freehold Area Health Department, 1 Municipal Plaza, Freehold, NJ
J. Med. Entomol. 44(5): 752Ð757 (2007)
ABSTRACT We monitored the abundance of Ixodes scapularis Say (Acari: Ixodidae) and the Lyme disease incidence rate after the incremental removal of white-tailed deer, Odocoileus virginianus Zimmermann, within a suburban residential area to determine whether there was a measurable decrease in the abundance of ticks due to deer removal and whether the reduction in ticks resulted in a reduction in the incidence rate within the human population. After three seasons, the estimated deer population was reduced by 46.7%, from the 2002 postfawning estimate of 2,899 deer (45.6 deer per km2) to a 2005 estimate of 1,540 deer (24.3 deer per km2). There was no apparent effect of the deer culling program on numbers of questing I. scapularis subadults in the culling areas, and the overall numbers of host-seeking ticks in the culling areas seemed to increase in the second year of the program. The Lyme disease incidence rate generated by both passive and active surveillance systems showed no clear trend among years, and it did not seem to vary with declining deer density. Given the resources required to mount and maintain a community-based program of sufficient magnitude to effectively reduce vector tick density in ecologically open situations where there are fe impediments to deer movement, it may be that deer reduction, although serving other community goals, is unlikely to be a primary means of tick control by itself. However, in concert with other tick control interventions, such programs may provide one aspect of a successful community effort to reduce the abundance of vector ticks.
Overpopulation problems December 20, 2010 Part 2 of 3 The Adirondack Daily Enterprise
Biologists Felicia Keesing and Richard Ostfeld reject the tick-Lyme disease connection, noting that studies in New York and New Jersey found no correlation between the number of deer and the number of ticks in a region. These researchers argue that when deer are scarce, ticks simply move to alternate hosts: raccoons, skunks, opossums and other medium sized animals. Keesing and Ostfeld note that Lyme disease is rare in Southeastern and most Midwestern states, regions of the country where deer are plentiful.
UMaine and Maine Medical Center study illustrates how Lyme disease-causing ticks have increased in Maine March 30, 2022 Bangor Daily News
... one small mammal in the study rose above the rest when it came to carrying blacklegged ticks... White-footed mice hosted just over 94% of all the blacklegged ticks found, and 15% of all white-footed mice had blacklegged ticks on them... The study was published in the Journal of Medical Entomology in December
Youtube Video: A young Mule Deer in Colorado Springs get help from a flock of Magpies who are eating parasites off his back.
A Contradictory Study: Information about problems with this study
The relationship between deer density, tick abundance, and human cases of Lyme disease in a residential community. Kilpatrick HJ, LaBonte AM, Stafford KC.
... After hunts were initiated, number and frequency of deer observations in the community were greatly reduced as were resident-reported cases of Lyme disease. Number of resident-reported cases of Lyme disease per 100 households was strongly correlated to deer density in the community. Reducing deer density to 5.1 deer per square kilometer resulted in a 76% reduction in tick abundance, 70% reduction in the entomological risk index, and 80% reduction in resident-reported cases of Lyme disease in the community from before to after a hunt was initiated.
In some news articles Dr Fish, a Lyme Researcher, associates Lyme Disease and Deer without research support. Explanation
Misinformation from USDA
Long Island, 2014 East End Deer Damage Management Report August 2014 New York, Prepared by: United States Department of Agriculture Animal and Plant Health Inspection Service Wildlife Service
... White-tailed deer are a vector of several prevalent and serious tick borne diseases on the East End of Long Island, including Lyme disease ... [White-tail deer are not a vector for Lyme disease. They are immune to Lyme and do not transmit the disease.]