Wood Tick Dermacentor Andersoni Research Articles

Increasing the paralyzing ability of a laboratory colony of Dermacentor andersoni Stiles.

Field-collected Rocky Mountain wood ticks Dermacentor andersoni Stiles from British Columbia caused limited paralysis in hamsters at high doses, but not at lower doses, while ticks collected from Alberta failed to cause paralysis. This prompted development of a laboratory strain of ticks with a more consistent ability to cause paralysis. Progeny of ticks that paralyzed a cow near Walhachin, British Columbia were reared and assayed for paralyzing ability. A high-virulence colony was selected for four generations using female ticks that cause paralysis singly on hamsters. A low-virulence colony was concurrently selected using female ticks that failed to cause paralysis at four ticks per hamster. Logistic regression indicated that the paralyzing ability of the high-virulence colony was consistently higher than that of the low-virulence colony, but that the paralyzing ability of both colonies increased through four generations of selection. Ticks required storage at 10 degrees C to terminate behavioral diapause. The effects of prolonged storage at 10 degrees C on the paralyzing ability of ticks was estimated and was small compared with differences between colonies and across generations. Single ticks from the high-virulence colony caused an increasing proportion of paralysis with each generation, but only limited paralysis with no increase across generations for the low-virulence colony. Single ticks from the high-virulence colony that caused paralysis were similar in weight and percent weight gain compared with single ticks that failed to cause paralysis. Engorged weight and egg mass production after four generations of rearing in the laboratory were similar to that measured for field-collected adults. Results indicated that laboratory selection could increase paralysis, but not eliminate it. This was likely a result of an inability to select male ticks.

Tick Removal

Several tick-borne infectious diseases that can affect children are prevalent in different geographic areas within the United States. Examples of these include: babesiosis, a protozoal infection transmitted by the deer tick(Ixodes scapularis); Colorado tick fever, which is an arboviral infection; and tularemia, a Gram-negative bacterial infection. Several rickettsial diseases also are spread by tick bites, including ehrlichiosis,which is spread by the tick vector Amblyomma americanum and possibly Ixodes scapularis, and Rocky Mountain spotted fever (RMSF). RMSF is transmitted in the South Atlantic/Southeastern states primarily by the dog tick Dermacentor variabilis, in the Western United States by the wood tick Dermacentor andersoni, and in the South Central region by the Lone Star tick, Amblyomma americanum.Perhaps the most notorious tick-borne disease in the United States today is Lyme disease, caused by the spirochete Borrelia burgdorferi. The disease is transmitted by the deer ticks Ixodes scapularis(previously Ixodes dammini) in the East/ Midwest and Ixodes pacificus in the West.Control measures for these and other tick-borne pediatric infectious diseases are aimed at preventing infected ticks from biting children. These measures include avoiding tick-infested areas; wearing protective clothing that covers exposed parts of the body; using tick/insect repellant; and carefully examining the child’s head, neck, and body following possible tick exposure.Any ticks that are discovered should be removed promptly either by using the fingers or fine tweezers. Whatever method is used, the tick should be grasped as close to the skin as possible and removed by pulling straight out. Twisting motions should be avoided. In addition, care should be taken not to squeeze the body of the tick. Fingers always should be protected by tissue paper and thoroughly washed with soap and water after tick removal.Adherence to the measures described can diminish the transmission of tick-borne diseases by reducing contact with ticks and preventing infected ticks from biting and engorging on children.Worldwide, only mosquitoes surpass ticks as arthropod vectors of human infections, and the range of infectious agents transmitted by ticks to people is an unfortunate reflection of nature’s almost infinite variety: virus, bacterium,protozoa, rickettsia, and spirochete,not to mention the noninfectious neurotoxin that causes tick paralysis. Children are particularly susceptible to tick-borne disease because they love to play in the kinds of places where ticks live, as do their pets,another common source of exposure.An article published in Pediatrics(Needham GR. Evaluation of five popular methods for tick removal. 1985;75:997) serves as the scientific basis for the recommendations outlined by Dr Ozuah. Despite what our grandmothers may have told us,neither petroleum jelly, fingernail polish, alcohol, nor a hot match works as well in extracting a tick intact as totally straight traction. Dr Ozuah points out that if fingers are used instead of tweezers, they should be protected by tissue or rubber gloves to keep infectious agents in the tick’s saliva from invading through breaks in the skin—an argument for not allowing children to “de-tick” their pets.Because of the risk of contamination with infectious agents from the tick’s saliva, the site of a bite should be disinfected carefully after the tick has been removed. Removed ticks should be put into a bottle of alcohol or flushed down the toilet.

Rocky Mountain spotted fever.

1. L. Akinbami, MD* 1. 2. *Pediatric Resident Children’s National Medical Center Washington, DC 1. Rocky Mountain Spotted Fever. Silber JL. Clin Dermatol . 1996;14:254-258 2. Lyme Disease, Rocky Mountain Spotted Fever, Ehrlichiosis: Emerging and Established Challenges for the Clinician. Jantausch BA. Ann Allergy . 1994;73:4-12 [OpenUrl][1][PubMed][2] 3. Treatment of Rocky Mountain Spotted Fever. Kamper C. J Pediatr Health Care . 1991;5:216-222 [OpenUrl][3][CrossRef][4][PubMed][5] 4. Therapeutic Delay and Mortality in Cases of Rocky Mountain Spotted Fever. Kirkland KB, Wilkinson WE, Sexton DJ. Clin Infect Dis . 1995;20:1118-1121 [OpenUrl][6][Abstract/FREE Full Text][7] 5. Rocky Mountain Spotted Fever. Weber DJ, Walker DH. Infect Dis Clin North Am . 1991;5:19-35 [OpenUrl][8][PubMed][9] Rocky Mountain spotted fever (RMSF) is a potentially fatal multisystem illness caused by Rickettsia rickettsii , a Gram-negative, obligate intracellular coccobacillus. A feeding tick inoculates the bacteria into the dermis from which they disseminate hematogenously and enter endothelial cells throughout the body. Intracellular replication leads to vasculitis and increased vascular permeability. The seasonal occurrence (April to October) of RMSF is associated with feeding activity of the vectors— the wood tick Dermacentor andersoni in Rocky Mountain states and the dog tick Dermacentor variabilis in the eastern two thirds of the United States. RMSF has been reported from every region of the continental United States, and the vector is found in both rural and urban areas. The incidence is highest in children ages 5 to 9 years. For all ages, risk factors include exposure to dogs, residence in wooded areas, and male gender. Clinical signs and symptoms of RMSF emerge after an average incubation of 1 week, which may range from 2 to 14 days, depending on the inoculum size. Patients present with fever, severe frontal headache, and myalgias, which make early RMSF difficult to distinguish from acute viral illnesses. Additional complaints … [1]: {openurl}?query=rft.jtitle%253DAnnals%2Bof%2Ballergy%26rft.stitle%253DAnn%2BAllergy%26rft.aulast%253DJantausch%26rft.auinit1%253DB.%2BA.%26rft.volume%253D73%26rft.issue%253D1%26rft.spage%253D4%26rft.epage%253D11%26rft.atitle%253DLyme%2Bdisease%252C%2BRocky%2BMountain%2Bspotted%2Bfever%252C%2Behrlichiosis%253A%2Bemerging%2Band%2Bestablished%2Bchallenges%2Bfor%2Bthe%2Bclinician.%26rft_id%253Dinfo%253Apmid%252F8030801%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [2]: /lookup/external-ref?access_num=8030801&link_type=MED&atom=%2Fpedsinreview%2F19%2F5%2F171.atom [3]: {openurl}?query=rft.jtitle%253DJournal%2Bof%2Bpediatric%2Bhealth%2Bcare%2B%253A%2B%2Bofficial%2Bpublication%2Bof%2BNational%2BAssociation%2Bof%2BPediatric%2BNurse%2BAssociates%2B%2526%2BPractitioners%26rft.stitle%253DJ%2BPediatr%2BHealth%2BCare%26rft.aulast%253DKamper%26rft.auinit1%253DC.%26rft.volume%253D5%26rft.issue%253D4%26rft.spage%253D216%26rft.epage%253D222%26rft.atitle%253DTreatment%2Bof%2BRocky%2BMountain%2Bspotted%2Bfever.%26rft_id%253Dinfo%253Adoi%252F10.1016%252F0891-5245%252891%252990067-Z%26rft_id%253Dinfo%253Apmid%252F1865296%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [4]: /lookup/external-ref?access_num=10.1016/0891-5245(91)90067-Z&link_type=DOI [5]: /lookup/external-ref?access_num=1865296&link_type=MED&atom=%2Fpedsinreview%2F19%2F5%2F171.atom [6]: {openurl}?query=rft.jtitle%253DClin%2BInfect%2BDis.%26rft_id%253Dinfo%253Adoi%252F10.1093%252Fclinids%252F20.5.1118%26rft_id%253Dinfo%253Apmid%252F7619985%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [7]: /lookup/ijlink?linkType=ABST&journalCode=cid&resid=20/5/1118&atom=%2Fpedsinreview%2F19%2F5%2F171.atom [8]: {openurl}?query=rft.jtitle%253DInfectious%2Bdisease%2Bclinics%2Bof%2BNorth%2BAmerica%26rft.stitle%253DInfect%2BDis%2BClin%2BNorth%2BAm%26rft.aulast%253DWeber%26rft.auinit1%253DD.%2BJ.%26rft.volume%253D5%26rft.issue%253D1%26rft.spage%253D19%26rft.epage%253D35%26rft.atitle%253DRocky%2BMountain%2Bspotted%2Bfever.%26rft_id%253Dinfo%253Apmid%252F1904897%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [9]: /lookup/external-ref?access_num=1904897&link_type=MED&atom=%2Fpedsinreview%2F19%2F5%2F171.atom

Arthropod vectors of human disease in the United States

Arthropod vectors of human disease in the United States

Neuro-Anatomical Site in Tick Paralysis

PREVIOUS studies1 have shown that tick paralysis, induced in mongrel dogs by applying the wood tick Dermacentor andersoni Stiles, is due to failure in transmission at the neuro-muscular junction because: (a) the anterior tibial muscle in a paralysed dog responded to direct but not to indirect stimulation through the peroneal nerve; (b) the motor nerve fibres conducted an impulse.

TULAREMIA, PULMONIC FORM

It has been only fifteen years since Edward Francis 1 described tularemia, a new disease in man. Since that time it has been widely recognized in all parts of the country. The ulceroglandular form is quite common in eastern Montana, where the wood tick Dermacentor andersoni and the jack rabbit are prevalent. We see relatively few cases due to the skinning of rabbits, since they are little used for food in this locality. Most of our cases are associated with tick bite or occur in the handling of tick-infested sheep. The incidence of infection varies greatly and seems to coincide with the rise and fall of the jack rabbit population. An epizootic of tularemia among the rabbits seems to kill off most of them and there is relative freedom from human tularemia for a few years until it develops in a new generation of rabbits. The present report is based

Rocky Mountain Spotted Fever: Investigation of Sexual Transmission in the Wood Tick Dermacentor andersoni

Rocky Mountain Spotted Fever: Investigation of Sexual Transmission in the Wood Tick Dermacentor andersoni