1Department that Energy and also Environmental Protection, Wildlife Division, 391 course 32, phibìc Franklin, CT 06254.

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1Department the Energy and Environmental Protection, Wildlife Division, 391 route 32, north Franklin, CT 06254.
3The Connecticut farming Experiment Station, 123 Huntington St., crate 1106, new Haven, CT 06504.
Journal of clinical Entomology, Volume 51, issue 4, 1 July 2014, Pages 777–784, https://aramuseum.org/10.1603/ME13232
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Abstract

White-tailed deer (Odocoileus virginianus Zimmerman), offer as the primary host for the adult blacklegged tick (Ixodes scapularis Say), the vector because that Lyme disease, human being babesiosis, and also human granulocytic anaplasmosis. Our objective was to advice the degree of association in between deer density, tick abundance, and human instances of Lyme disease in one Connecticut ar over a 13-yr period. Us surveyed 90–98% of every permanent citizens in the neighborhood six time from 1995 to 2008 to document resident"s exposure come tick-related condition and frequency and also abundance of deer observations. After hunts to be initiated, number and also frequency of deer monitorings in the community were greatly diminished as to be resident-reported instances of Lyme disease. Variety of resident-reported instances of Lyme disease per 100 households was strongly correlated to deer density in the community. Reduce deer thickness to 5.1 deer per square kilometer led to a 76% reduction in mite abundance, 70% palliation in the entomological hazard index, and also 80% reduction in resident-reported situations of Lyme disease in the neighborhood from before to ~ a hunt to be initiated.


B. Burgdorferi, hunting, Ixodes scapularis, Lyme disease, Odocoileus virginianus

White-tailed deer (Odocoileus virginianus Zimmerman), serve as the primary organize for the adult blacklegged mite (Ixodes scapularis Say), the vector for Lyme disease, person babesiosis, and human granulocytic anaplasmosis (ehrlichiosis; Spielman et al. 1985, Spielman 1988, Bakken et al. 1994). Numerous researchers have correlated tick abundance through deer diversity (Rand et al. 2003, Stafford et al. 2003, Wilson et al. 1990). A hopeful correlation to be found between density of deer pellet groups and also adult tick densities in Maine (Rand et al. 2003) and between deer densities and tick variety in Connecticut and brand-new York (Wilson et al. 1990, Stafford et al. 2003). Anderson et al. (1987) evaluate the presence of I. Scapularis (then Ixodes dammini Spielman, Clifford, Piesman & Corwin) and also the Lyme disease agent, Borrelia burgdorferi, on six coastal islands in Rhode Island and found the blacklegged tick and B. Burgdorferi only on islands occupied by deer. The association in between deer activity, deer and tick abundance, and the transmission of Lyme condition has to be recognized, but not well quantified (Rand et al. 2003).

Several studies have documented the influence of decreased deer number on blacklegged tick activity. Mite numbers decreased with the palliation of deer in ~ the Bluff Point coastal Preserve in Groton, CT, and also a forested street in Bridgeport, CT (Stafford et al. 2003). Near elimination that deer on great Island and also Crane beach in Massachusetts brought about reduction the ticks in years adhering to the deer reduction (Wilson et al. 1988, Deblinger et al. 1993). Similarly, elimination of deer ~ above Monhegan Island in Maine led to a decrease in tick abundance and also infection prices (Rand et al. 2004). Telford (1993) report that prior to the deer palliation on an excellent Island, a peninsula on Cape cod Massachusetts, 20% of citizens contracted a tick-related disease. ~ deer were reduced from in between 39–65 deer every square kilometre to 1–3 deer per square kilometer, no new cases the tick-related disease were reported end the following 8 yr (Steere et al. 1986, Wilson et al. 1988, Telford 1993).

It is unclear how low deer densities should be reduced to impact tick abundance saturated to reduce the incidence of human Lyme disease. Telford (1993) argued that deer populations need to be lessened to 90% (Mount et al. 1997). However, various other models suggest that adult master (white-tailed deer) had actually no affect on managing tick population densities under most circumstances (VanBuskirk and also Ostfeld 1995, Ostfeld et al. 2006).

Only Steere et al. (1986) and also Telford (2002) reported a reduction in tick-related condition in humans after a palliation in the deer population; however, no details were provided on the sampling methods. Kilpatrick and Walter (1997) and also Kilpatrick and also LaBonte (2003) report reduced neighborhood concerns about deer and Lyme an illness the year adhering to a managed deer hunt. However, no studies have simultaneously evaluated the relationship between deer density, mite abundance, and also incidence that Lyme an illness in human beings before and also after initiating a deer reduction regime in a residential community. Our objective to be to evaluate the level of association in between deer density, mite abundance, and also human cases of Lyme condition in one Connecticut community over a 13-yr period.

Study Area

The study area was the Mumford Cove (MC; 80.9-ha) ar in Groton, CT. The number of occupied resident in MC year-round varied from 98 come 119 during the study. Home lots were ≤0.61 ha each. MC was located on a 1.9-km2 seaside peninsula bordered by lengthy Island Sound come the east and also west. Phibìc of the peninsula to be an 80-ha undeveloped state park closed to hunting and separated indigenous MC by a 1.83-m-high chain-link fence. South of MC was the 105.9-ha residential neighborhood of Groton long Point. Nearby to residential breakthrough in MC were 3 tracts the open room (24.5, 22.7, and also 21.4 ha each; Fig. 1).



A regional ordinance prohibiting hunting in MC permitted the neighborhood deer population to flourish unimpeded. As a an outcome of this population growth, residents concerns connected with overabundant deer populations raised in the 1990s (Kilpatrick et al. 1996). Native 1995–2000, 63 woman deer to be radio collared and ear tagged (83–100% of annual estimated feather female population over a 6-yr period) and also 13 males were ear tagged only in the community to study deer movements (Kilpatrick and Spohr 2000a, b). In July 2000, the ar voted to remove the no-hunting ordinance, and also implement a deer hunt in their community (Kilpatrick et al. 2002).

A 6-d shotgun-archery hunt in November 2000 on 2 of 3 tracts that open an are reduced the target deer herds by 92% (Kilpatrick et al. 2002). The adhering to year the third tract the open room was opened up to hunting. A 3-d shotgun-archery hunt during November 2001 targeted deer herds ~ above all 3 tracts the open space and decreased the existing deer populace by 82%. Over the next 6 yr (2002–2007), a team of two to three hunters to be assigned to each tract that open space during the archery deer season (15 September–31 December) to preserve the deer populace at low densities. Under existing state hunting regulations, archery hunters were allowed to harvest unlimited numbers of antlerless deer. In 2003, the archery season was extended to 31 January and hunters were permitted to hunt over bait.

Methods

Population Estimate.

We performed aerial deer surveys 9 the 13 yr in between 1995 and 2007 (1995, 1996, 1999, and 2002–2007) native a helicopter when complete snow cover was available during January or February. All radio-collared deer were evidenced to be in the examine area at the time of the surveys. Before the hunt, a correction variable was developed to account for deer not observed throughout aerial surveys. The correction element was based upon the variety of known radio-collared deer in the populace compared v the number of radio-collared deer observed during aerial surveys (Kilpatrick et al. 2001). This correction element of 2.2 was used to all deer counts to estimate deer densities.

Homeowner Surveys.

We surveyed every permanent inhabitants in MC six times indigenous 1995 come 2008. We asked citizens if a physician had diagnosed castle or any kind of member the their household with Lyme condition and throughout which years. On every surveys citizens were asked come indicate throughout what year they contract Lyme condition which extended a 12-yr duration (1996–2007). On 4 of six surveys, we additionally asked occupants how frequently they it was observed deer and also how countless they observed (1995, 1999, 2001, and 2005). Deer monitorings were categorized into team sizes consists of 0, 1–3, 4–6, 7–9, and also 10+. Because that our analysis, we concentrated on size of ≥4 due to the fact that it most likely represented an extensive family team consisting of more than a doe and her immediate offspring.

The an initial survey was carried out by walk door-to-door in respectable 1995, before initiation of any type of deer monitoring program. Because that the remaining 5 surveys, we conducted a mail-back inspection of all permanent inhabitants in MC complying with methodologies argued by Dillman (1978). The 2nd survey was performed in august 1999 prior to the controlled hunt to be initiated. Based upon the timing of the surveys, some questions referenced interactions from previous years to incorporate complete years that data. The third (July 2001) and also fourth surveys (September 2002) were conducted after the first (2000) and second (2001) controlled hunts to be completed. The fifth and sixth surveys were conducted in July 2005 and also 2008 after bow hunting was created in the ar as an yearly management program.

The study protocol and also surveys to be reviewed and also approved by the Connecticut Wildlife Division. We performed surveys in accordance to federal guidelines by not included minors, ensuring outcomes were not identifiable to individuals, and ensuring the the surveys affiliated no dangers to individuals.

Tick Collection.

The variety of host-seeking nymphal blacklegged ticks in MC was monitored by dragging a 1-m2 fleece towel along transects at lawn edges and also at wooded plots varying from 25 to 137 m in length. Sampling arisen May with September native 2001 to 2007. Typical nymphal mite abundance every 100 m2 was based on June and July top season samples. Every nymphs the I. Scapularis were went back to the activities for experimentation for B. Burgdorferi by indirect florescent antibody staining that mid-gut tissues as previously described (Magnarelli et al. 1987). One entomological danger index (ERI) or average variety of infected ticks every unit area to be calculated as the product that the average variety of nymphs every area and proportion the ticks infected through B. Burgdorferi (Stafford et al. 1998).

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We used the very least square straight regression evaluation (Systat Software, Inc., san Jose, CA) to test for correlations between cases of Lyme condition and deer densities, daily deer sightings, and nymphal mite abundance (P 9.0 = 0.254; P Fig. 2). Before hunting (1995 and 1999), more than half of master in the ar (51–60%) generally observed ≥4 deer in a group and also the number of deer observed was comparable between year (ρ 3.0 = −0.099; P = 0.175). One year after searching was enforced (2001), only 27% the homeowners observed ≥4 deer in a group and also typical team size that deer observed in the neighborhood declined (ρ 3.0 = 0.217; P = 0.002) contrasted with one year before the hunt. Four years after searching was enforced (2005), 14% of homeowners observed ≥4 deer in a group and typical group size of deer it was observed in the neighborhood continued to decrease (ρ 3.0 = −0.178; P = 0.007) contrasted with 1 yr ~ the hunting (2001; Fig. 2).