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Biomedical subjects

D Fish

Publications and source records attributed to D Fish.

At least 109 records · Page 6Linked to original sources
PubMed1989

Host associations of ticks (Acari: Ixodidae) parasitizing medium-sized mammals in a Lyme disease endemic area of southern New York.

Ticks of eight medium-sized mammal species were studied in an area of endemic Lyme disease in Westchester County, N.Y., from 1 April 1984 to 31 March 1985. Most (81%) of the 266 total mammal captures were raccoon, Procyon lotor (L.) (47%), opossum, Didelphis virginiana (Kerr) (19%), and striped skunk, Mephitis mephitis Schreber (15%); these host species accounted for 91% of the 1,519 ticks collected. Although the total number of ticks was rather evenly distributed among these mammals, species composition of ticks on each host species differed markedly. Ixodes dammini Spielman, Clifford, Piesman, and Corwin was the most abundant tick species and accounted for 45% (690) of the total ticks collected. Immatures were most prevalent (56%) on opossum, and nearly all (86%) adults were found on this host species. I. cookei Marx was second in abundance (34%) and was most prevalent (60%) on skunk. I. texanus Banks and Dermacentor variabilis (Say) were less abundant (less than 20% collectively) and were most prevalent on raccoon. I. dentatus Marx on eastern cottontail, Sylvilagus floridanus (Allen), and I. marxi Banks on gray squirrel, Sciurus carolinensis Gmelin, were least abundant (less than 2% collectively). The prevalence of I. dammini on medium-sized mammals in southern New York may influence the epizoötiology of Lyme disease.

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PubMed1989

Seasonal activity and survival of adult Ixodes dammini (Acari: Ixodidae) in southern New York State.

Mark-recapture studies demonstrated that adult Ixodes dammini Spielman, Clifford, Piesman, and Corwin in southern New York successfully overwinter and resume active host-seeking in the spring. Thus, the resulting bimodal peak in autumn and spring appears to reflect temperature-induced activity of the same cohort and not different generations. Adult tick abundance in the field was monitored by counting the number of ticks collected by a domestic dog on routine walks and correcting for the effects of temperature on tick activity. It is suggested that adult abundance, measured independently of ambient temperature, may be an accurate indicator of survival. The field tick abundance curve was negatively exponential (y = e(4.26-0.12x] and significantly different from the survival curve for ticks maintained in the laboratory, which displayed a constant mortality rate (y = -3.7x + 105.5). Body size influenced male survival during the winter, whereas female survival was independent of body size. Greater male mortality in fall and winter resulted in a lower sex ratio in spring.

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PubMed1989

Potential for exposure to tick bites in recreational parks in a Lyme disease endemic area.

Eight recreational parks located in a Lyme disease endemic area of southern New York State were surveyed for the presence of ticks during the summer of 1985 by drag sampling. Ixodes dammini, the primary vector of Lyme disease in the northeast, was found in all but one park and accounted for 580 (91.8 per cent) of the 632 ticks collected. Of these, 18 per cent were larvae, 80 per cent were nymphs, and 2 per cent were adults. An I. dammini encounter distance, defined as the mean number of meters traveled before encountering a nymphal or adult I. dammini on a drag cloth, ranged from 36 m in high-risk parks, to infinity (no tick encounters). Generally, areas of high use presented higher encounter distances (lower risk) than those of the entire park. Two of the three parks with the highest annual attendance also had the highest I. dammini population indices as projected from our sampling regimen. These results indicate that recreational parks in Lyme disease endemic areas represent a substantial human risk for tick bites and Lyme disease.

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PubMed1988

Prevalence of Ixodes dammini near the homes of Lyme disease patients in Westchester County, New York.

Cases of Lyme disease that occurred in Westchester County, an affluent suburb north of New York City, in 1983 were investigated in 1983 and 1984 to determine the presence of Ixodes dammini (Acari: Ixodidae) in the vicinity of the patients' homes. Small mammal trapping, drag cloth, and carbon dioxide-baited tick traps were used to sample ticks. In all but one of 11 cases investigated, I. dammini was found on or near well-maintained lawns in the immediate vicinity of the residences. A mark-release-recapture experiment to determine tick abundance in one 700 m2 lawn resulted in an estimate of 6800 adult ticks (approximately 1 per m2). Dark-field microscopic examination of tick midgut tissues revealed that 33% of nymphs and 55% of adult ticks from this lawn contained spirochetes. These data suggest that many cases of Lyme disease in Westchester County, New York, may be acquired at home as a result of activities on the lawn.

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PubMed1988

Ticks parasitizing humans in a Lyme disease endemic area of southern New York State.

A total of 126 tick specimens were submitted by tick bite victims to the Westchester County Department of Health, White Plains, New York, and to the New York Medical College, Medical Entomology Laboratory, Armonk, New York, during 1985. These included 96 (76.2%) Ixodes dammini, 26 (20.6%) Dermacentor variabilis, and two (1.6%) Amblyomma americanum. I. dammini parasitism was reported during all months of the year except December and February and involved all life stages. Only D. variabilis adults parasitized humans, with all cases occurring in the spring and summer. The mean age of I. dammini victims was 24.5 years, with 39.0% under age 10 years. This age group also accounted for 52.0% of all D. variabilis victims (mean age, 16.8 years). The majority of I. dammini and D. variabilis were though to be acquired in the victims' yards (68.6 and 64.7%, respectively). Attachment sites for these species were significantly different, with I. dammini nymphs found most frequently on the lower extremities and I. dammini adults and D. variabilis adults found primarily on the head. Prophylactic antibiotic treatment was prescribed by a physician for 40.8% of I. dammini victims, compared with 4.5% of the D. variabilis victims. Lyme disease was reported by two patients during the course of the study. Neither had received prophylactic therapy at the time of the reported tick bite.

Adolescent↗
PubMed1988

Serologic analyses of Peromyscus leucopus, a rodent reservoir for Borrelia burgdorferi, in northeastern United States.

An enzyme-linked immunosorbent assay (ELISA) and indirect fluorescent-antibody test were used to detect antibodies to Borrelia burgdorferi, the causative agent of Lyme disease, in Peromyscus leucopus (white-footed mouse). Of the 661 mice captured in Connecticut, Rhode Island, and New York during 1980 and 1983 to 1987, 166 (25.1%) had antibodies to B. burgdorferi by ELISA. Comparative analyses of 210 serum specimens, collected in areas where Lyme disease is endemic, revealed a threefold difference in sensitivity between the ELISA (38.1% positive) and the indirect fluorescent-antibody method (12.4%). Although prevalence of seropositive P. leucopus was highest during June, elevated amounts of antibody (1:1,280 to 1:2,560) were detected in mice that harbored spirochetes during all seasons. Being reservoirs for B. burgdorferi, these rodents are suitable for monitoring spirochete infections at foci and should be included in field evaluations of control programs aimed at suppressing Lyme disease.

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PubMed1987

Choroid plexitis in white-tailed deer (Odocoileus virginianus) in southern New York State.

Brains, spinal cords, nerve roots, nerves and muscle tissues were removed from deer in southern New York State and examined for histologic evidence of infection by the causative agent of Lyme disease, Borrelia burgdorferi. There was no histologic evidence of this infection and only four of 26 deer had serologic evidence of past infection despite the fact that all were parasitized by the tick vector, Ixodes dammini. Of these ticks, 21% were carrying B. burgdorferi. In contrast, most of the deer had choroid plexitis. All but one of 48 deer tested were infected with Trypanosoma cervi, 20 of 24 deer had sarcocystis in skeletal muscles and two had dural lesions probably due to the nematode Pneumostrongylus tenuis. The causal relationship between choroid plexitis and trypanosomiasis is discussed.

Animals↗
PubMed1986

Spirochetes in ticks and antibodies to Borrelia burgdorferi in white-tailed deer from Connecticut, New York State, and North Carolina.

Ticks were screened for spirochetes and serum samples from white-tailed deer (Odocoileus virginianus) were assayed for antibodies to Borrelia burgdorferi during 1983-1984. Using fluorescein isothiocyanate-labeled rabbit antibodies produced to B. burgdorferi, the etiologic agent of Lyme disease, spirochetes were detected in Ixodes dammini (10.5% of 1,193) and Dermacentor albipictus (0.6% of 157) adults from Connecticut, I. dammini nymphs (49.1% of 108) and adults (64.7% of 99) from Armonk, New York, and in I. scapularis (0.4% of 531) and Amblyomma americanum (3.5% of 173) adults from North Carolina. Infected ticks were either seeking hosts or feeding on deer during the summer and fall. Direct fluorescent antibody staining also revealed spirochetes in two larvae of I. scapularis that emerged from eggs deposited by separate females in the laboratory. Using indirect immunofluorescence tests, antibodies to B. burgdorferi were identified in white-tailed deer living in tick-infested areas of all three states. Aside from minor cross-reactivity, there was no serologic evidence of Treponema or Leptospira infections. Ixodes dammini is a primary vector of B. burgdorferi in northeastern United States, but in North Carolina, other ixodid ticks may transmit this spirochete to humans and wildlife.

Animals↗
PubMed1984

Passive stiffness of isolated cardiac and skeletal myocytes in the hamster.

Single cardiac myocytes and skeletal myocyte fragments, devoid of interstitial collagen but with intact glycocalyx, were prepared by mechanical disaggregation of hamster ventricular myocardium and caudal gracilis muscle, respectively. Passive stiffness was studied by examining the sarcomere length-tension relationship over the approximate Eulerian stress range of 0-20 mN/mm2 for cardiac myocytes and 0-120 mN/mm2 for skeletal myocytes. Creep and stress-relaxation became apparent only when cells were stretched to sarcomere lengths close to, or exceeding, 2.2 micron for the cardiac myocytes, and 2.7 micron for the skeletal myocytes. Stress-relaxation and creep occurred simultaneously, suggesting that the sarcomere is at least one of the structural components responsible for viscoelasticity. The differential strain stiffness constant was calculated from the regression of natural stress [Ln(mN/mm2)] against differential strain [(L-Lo)/Lo] and found to be 7.48 +/- 1.73 for the ventricular myocytes and 5.77 +/- 0.87 for the skeletal myocyte fragments. The natural strain stiffness constant was obtained from the regression of natural stress against natural strain [Ln(L/Lo)]. The natural strain stiffness constant was 30-50% higher than the differential strain constant. The high correlation coefficients obtained for both regressions indicate that the length-tension relationships for these isolated cardiac and skeletal myocytes can be very closely fitted to the single exponential function, sigma = C X exp[K(epsilon)]. The length-tension curves obtained for the skeletal myocyte fragments are qualitatively and quantitatively similar to those obtained by others with intact skeletal muscle. The cardiac myocyte length-tension curves are qualitatively, but not quantitatively, similar to those obtained with cardiac muscle. Isolated ventricular myocytes are stiffer than similarly isolated skeletal myocytes. These findings suggest that cellular structures contribute to myocardial stiffness in the hamster.

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PubMedDate not supplied

Emerging zoonoses.

Explore the source record for details and available documents.

Animals↗
PubMedDate not supplied

Disparity in the natural cycles of Borrelia burgdorferi and the agent of human granulocytic ehrlichiosis.

We studied the prevalence of Borrelia burgdorferi and the agent of human granulocytic ehrlichiosis (HGE) among questing nymphal and adult Ixodes scapularis ticks of the same generation and the infectivity of wild white-footed mice for ticks feeding on them. The prevalence of B. burgdorferi infection in host-seeking ticks increased less than twofold from nymphal (31% to 33%) to adult (52% to 56%) stage, and 52% of white-footed mice were infected. Prevalence of the agent of HGE increased 4.5- to 10.6-fold from nymphal (1.5% to 1.8%) to adult stage (7.6% to 19.0%), while only 18% of mice were infectious to ticks. B. burgdorferi infection was more common in mouse-fed ticks than in ticks collected from vegetation, whereas the agent of HGE was half as common in mouse-fed ticks as in ticks collected from vegetation. The different prevalence in nature of these pathogens in ticks suggests that their maintenance cycles are also different.

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