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Biomedical subjects

D Fish

Publications and source records attributed to D Fish.

At least 91 records · Page 5Linked to original sources

The biological and social phenomenon of Lyme disease.

Lyme disease, unknown in the United States two decades ago, is now the most common arthropod-borne disease in the country and has caused considerable morbidity in several suburban and rural areas. The emergence of this disease is in part the consequence of the reforestation of the northeastern United States and the rise in deer populations. Unfortunately, an accurate estimation of its importance to human and animal health has not been made because of difficulties in diagnosis and inadequate surveillance activities. Strategies for prevention of Lyme disease include vector control and vaccines.

Animals↗

Reduction of nymphal Ixodes dammini (Acari: Ixodidae) in a residential suburban landscape by area application of insecticides.

Seven formulations of three commercially available insecticides were evaluated for their ability to reduce the density of nymphal deer ticks (Ixodes dammini Spielman, Clifford, Piesman & Corwin) in a suburban residential area endemic for Lyme disease. In total, 101 residential properties in Mount Kisco, Westchester County, NY, were treated with one of the following: carbaryl emulsifiable concentrate (EC) at 0.6 or 1.1 kg AI/ha, carbaryl granular (GR) at 4.5 kg AI/ha, chlorpyrifos wettable powder (WP) at 0.6 or 1.1 kg AI/ha, chlorpyrifos GR at 1.1 kg AI/ha, or cyfluthrin EC at 0.1 kg AI/ha. All three chemicals were found to reduce the density of nymphs on treated properties significantly compared with untreated controls. Percentage of reduction of nymphs ranged from 67.9% for carbaryl EC 1.1 kg AI/ha to 97.4% for chlorpyrifos WP 1.1 kg AI/ha. There was no difference in the amount of reduction provided by each formulation of the same chemical, but carbaryl formulations were significantly less effective than chlorpyrifos or cyfluthrin. Nymphal densities after treatment remained low throughout the course of the study, indicating that a single well-timed spring application is sufficient to provide significant reduction of nymphs for an entire transmission season.

Animals↗

Canine exposure to Borrelia burgdorferi and prevalence of Ixodes dammini (Acari: Ixodidae) on deer as a measure of Lyme disease risk in the northeastern United States.

Surveillance programs that identify areas where both the vector (Ixodes dammini) and etiologic agent (Borrelia burgdorferi) are present may identify the risk of Lyme disease and its spread earlier and more accurately than do programs relying on any single method, particularly human case reports. Hunter-killed deer (n = 1,204) from 22 counties in Maryland, Massachusetts, New Hampshire, New York, and Pennsylvania were examined in fall 1989 and all ectoparasites were identified. The following spring, canine sera (n = 884) were obtained from these sites, which included known endemic areas and those where Lyme disease is uncommon, and tested by enzyme-linked immunosorbent assay. Regression analysis of canine seroprevalence versus tick prevalence on deer from the same counties demonstrate a significant positive linear relationship. Sites were designated as low-, moderate-, or high-risk counties based upon their position on the regression curve. The geographic distribution of the sites correlated well with the distribution of known Lyme disease endemic and nonendemic areas. Locations were also identified where Lyme disease may be emerging. The positive relationship between measures of vector and pathogen abundance determined in this study permits public health workers to identify endemic and potentially endemic areas independently of human case reports.

Animals↗

Relative importance of bird species as hosts for immature Ixodes dammini (Acari: Ixodidae) in a suburban residential landscape of southern New York State.

Abundance of birds and their tick parasites were estimated in a residential community located in Westchester County, NY, where Lyme disease is endemic. In total, 36 bird species (416 captures) were collected, of which 25 species (69%) were parasitized by ticks. Ixodes dammini Spielman, Clifford, Piesman & Corwin composed 96.4% of the 1,067 ticks found on birds. The bird species most heavily parasitized was house wren, Troglodytes aedon Vieillot (11.1 Ixodes dammini per bird). Relative density estimates of birds, using fixed circle radius counts, revealed dominance by the American robin, Turdus migratorius L. (29.3%), followed by the common grackle, Quiscalus quiscula (L.) (9.3%). Bird density estimates were combined with tick abundance data to calculate an importance value for each bird species as a host for immature I. dammini. The American robin was most important, accounting for 72.7% of all larval I dammini found on birds, followed by the common grackle (8.2%) and the house wren (5.9%). Both the American robin and house wren are reservoir competent for the Lyme disease spirochete Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner and therefore may contribute to the risk of Lyme disease for humans. During August when larvae were most prevalent, 39% of the American robins and 70% of the common grackles were observed on lawns. These species are probable contributors to nymphal I. dammini populations found on lawns.

Animals↗

Reduced abundance of Ixodes scapularis (Acari: Ixodidae) and Lyme disease risk by deer exclusion.

The effect of deer exclosures upon the numbers of immature Ixodes scapularis Say, the vector of Lyme disease in the eastern United States, was examined at five sites in Westchester County, NY. Study areas ranged in size from 6 to 101 ha where deer had been excluded for a period of 25 yr by > 2.4-m-high fencing that surrounded each site. A total area of 40,506 m2 was drag-sampled during the study to measure tick abundance. Nymphal densities (ticks per 1,000 m2) averaged 4.6 (range, 1.3-9.6) inside exclosures and 27.7 (range, 7.3-79.4) outside. Larval densities averaged 36.7 (range, 1.2-132.1) inside exclosures and 354.4 (range, 7.5-914.5) outside. Comparisons between exclosure sites and outside areas immediately adjacent to the exclosure fence, where deer had unrestricted access, revealed that exclosures had 83% fewer host-seeking nymphs and 90% fewer host-seeking larvae. Tick numbers inside exclosures did not always decline with increasing distance from the fence. There was no significant difference in the rate of Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner infection for host-seeking ticks collected inside (20%, n = 50) exclosures compared with ticks collected outside (26%, n = 50) exclosures. Deer fencing may provide a means of significantly reducing the abundance of I. scapularis and the risk of Lyme disease in relatively large areas without the need to reduce or eliminate the deer population.

Animals↗

Important characteristics of warning displays on alcohol containers.

Four studies examined the federally mandated warning on alcohol containers, which is required by law to be "located in a conspicuous and prominent place." In all four studies few of the drinkers could recall the main parts of the warnings, even though the warning had been required on all alcohol containers for over two years. In Study 1, 44 adults looked at the warning on various beer containers and 77% thought that the warning was not conspicuous but could be made conspicuous through various changes, such as by printing the warning horizontally (parallel to the brand name) rather than vertically. In Study 2, 50 adults looked at the warning placed horizontally on one beer can and vertically on a similar can and rated the horizontal warning significantly more conspicuous. In Study 3, 44 adults spent several minutes in a simulated drinking atmosphere. Half the subjects had beer cans with a horizontal warning and half had a vertical warning. The subjects with the horizontal warning later showed significantly better awareness/recall of the warning. In Study 4, with 75 adult subjects in a bar, the half of the subjects prompted to notice the alcohol warning drank less thereafter in the bar than the other subjects. The findings of the series of studies suggest that the conspicuousness of health warnings on alcohol containers tends to influence their possible effectiveness.

Accidents, Traffic↗

The distribution of canine exposure to Borrelia burgdorferi in a Lyme-Disease endemic area.

OBJECTIVES: A serosurvey of canine exposure to Borrelia burgdorferi, the causative agent of human Lyme disease, was conducted in Westchester County, New York, to determine the distribution of exposure in an area endemic for Lyme disease. METHODS: A total of 1446 blood samples was collected from resident dogs and tested by modified enzyme-linked immunosorbent assay. Equivocal samples were further tested by immunoblot. A mean number of 57.8 samples was collected from each of 25 towns and cities. RESULTS: Seroprevalence rates for municipalities ranged from 6.5% to 85.2%. County seroprevalence was 49.2%. There was a significant difference among the rates for the northern (67.3%), central (45.2%), and southern (17.3%) regions. Multiple range analysis indicated homogeneity between the southern and central regions and the central and northern regions. CONCLUSIONS: Canine exposure to B burgdorferi increases in a south to north gradient within the county. Intensity of exposure, measured by enzyme-linked immunosorbent assay titers, indicates a similar pattern. The close association between dogs and humans suggests that human risk of acquiring Lyme disease within Westchester County is equally disparate and is inversely related to the degree of urbanization.

Animals↗

Entomologic and demographic correlates of anti-tick saliva antibody in a prospective study of tick bite subjects in Westchester County, New York.

We measured anti-tick saliva antibody (ATSA) by enzyme-linked immunosorbent assay using whole sonicated Ixodes dammini salivary glands as antigen in subjects with 1) a recent and confirmed I. dammini (n = 100) or Dermacentor variabilis bite (n = 3), 2) erythema migrans (n = 15), 3) late-stage Lyme disease (n = 4), and 4) normal controls without a history of tick bites (n = 5). Tick bite subjects had three ATSA determinations over approximately six weeks. On the first ATSA measurement at a mean +/- SD of 18.5 +/- 19.8 hr after removal of the tick, the subjects bitten by I. dammini had a mean ATSA optical density value (95% confidence interval [CI]) of 0.264 (0.223, 0.305); the corresponding value in controls was 0.142 (0.115, 0.169). There was no consistent change in ATSA levels in individuals with time. Multiple linear regression indicated that tick engorgement (P < 0.01), subject age (higher ATSA with increasing age; P = 0.01), and subject sex (females > males; P = 0.03) were all independent predictors of ATSA levels. Logistic regression revealed that a bite by I. dammini that became engorged (defined as an engorgement index > or = 3.4) was a risk factor for ATSA seropositivity (odds ratio [95% CI] = 6.2 [1.7, 21.8]). Finally, the ATSA test had a sensitivity of 0.81 and a specificity of 0.56 for a bite by I. dammini that became engorged. Overall, the data are further evidence that ATSA is a biologic marker of tick exposure, in that the engorgement index, a surrogate for tick saliva dose, was the strongest independent predictor of antibody response.

Adolescent↗

A comparison of methods for sampling the deer tick, Ixodes dammini, in a Lyme disease endemic area.

The purpose of this study was to compare the trapping and examining of mice, drag sampling, and CO2-baited traps for their ability to detect the presence and abundance of immature deer ticks, Ixodes dammini, in a Lyme disease endemic area in southern New York State. Eight study sites were sampled 14 times between 28 May and 31 August by setting 49 live-traps, four CO2-baited traps, and drag sampling 500 m2. A total of 1540 nymphs and 3079 larvae was collected during the study. Drag sampling collected the most nymphs (705), while more larvae were recovered from CO2-baited traps (1105). Comparisons among the methods showed a significant difference in the numbers of both larval and nymphal ticks collected (P less than 0.01). There was a positive correlation between the numbers of nymphs collected by drag sampling and CO2-baited tick traps (rs = 0.83, P less than 0.05), and between the numbers of larvae collected by drag sampling and mouse trapping (rs = 0.75, P less than 0.05). These results suggest that drag sampling would be the single most reliable method for quantitatively sampling immature I. dammini populations in a Lyme disease endemic area.

Analysis of Variance↗

Multimodality imaging and intracranial EEG display for stereotactic surgery planning in epilepsy.

We describe a computer program for stereotactic surgery planning based on multimodality imaging and the display of intracranial EEG data in relation to anatomical data. The program is primarily designed to be used by surgeons to assist them in localizing brain structures and plan the safe and accurate insertion of surgical tools and depth electrodes. The mathematics underlying these concepts are briefly described. Estimates of the accuracy of the procedures are calculated and made available to the user. An extension of the program was developed to integrate intracranial EEG data with conventional images in order to help the neurologist and neurosurgeon in visualizing the EEG data in relation to the anatomy. It can be used to visualize the measured EEG voltages, or processed signals such as the application of the tetrahedral field calculation, which provides an extension of conventional bipolar EEG to 3 dimensions.

Brain↗

Landscape ecology of Lyme disease in a residential area of Westchester County, New York.

The landscape ecology of Lyme disease was studied in 1989 on 67 residences in an endemic area of Armonk, Westchester County, a northern suburb of New York City. Four main habitat types were defined, and each property was surveyed for immature and adult lxodes dammini ticks; 98.6% of 1,790 ticks collected were I. dammini. Overall, 67.3% were collected from woods, 21.6% from ecotone (unmaintained edge), 9.1% from ornamental vegetation, and 2% from lawns. Larval ticks were concentrated in woods, but nymphs and adults were widely dispersed in all habitats. Tick abundance was positively correlated with property size. Larger properties (greater than or equal to 0.5 acre) were more likely to have woodlots and, hence, more ticks. Dark-field and direct fluorescent microscopic examination of tick midgut tissues revealed that 29.6% of nymphs and 49.7% of adults were infected with Borrelia burgdorferi. Infected nymphs and adults were found on 36% and 60% of properties, respectively. These data indicate that the abundance of ticks capable of transmitting Lyme disease spirochetes is related to landscape features of the suburban residential environment.

Animals↗

Evaluation of host-targeted acaricide for reducing risk of Lyme disease in southern New York state.

A 2-yr evaluation of a commercial product designed to reduce the risk of Lyme disease by delivering permethrin-treated cotton to white-footed mice (Peromyscus leucopus) was conducted at three sites in Westchester County, N.Y., an area where Lyme disease is endemic. We examined the numbers of host-seeking nymphal Ixodes dammini Spielman, Clifford, Piesman & Corwin, the numbers of larval I. dammini infesting mice, and the proportion of nymphs infected with Borrelia burgdorferi, the causative agent of Lyme disease. The density of nymphs collected by drag sampling did not differ between treatment and control areas in the first year for either a woodland or recreational site. In the second year, no significant decrease in the density of nymphs was observed in the treatment areas compared with the control areas. Numbers of larvae on 67 mice captured on treatment and control grids did not differ for woodland and recreational sites, but significantly fewer larvae were found on mice captured at the residential treatment site. The percentage of host-seeking ticks infected with spirochetes did not differ between treatment and control sites in any habitat for either year. The use of permethrin-treated cotton did not measurably reduce the numbers of I. dammini or the proportion of ticks infected with spirochetes at our study sites.

Animals↗

Horizontal movement of adult Ixodes dammini (Acari: Ixodidae) attracted to CO2-baited traps.

The ability of male and female deer ticks, Ixodes dammini Spielman, Clifford, Piesman, & Corwin, to move horizontally was evaluated by performing a mark-recapture study. In each of two experiments, 120 ticks were marked with fluorescent powder and released at predetermined distances from a CO2-baited trap. The mean recruitment distance was 1.8 m after 6 d of trap operation. This distance is appreciably lower than those calculated from previous studies of several other species of ixodid ticks, including Amblyomma americanum (9.9 m for 48 h) and Dermacentor andersoni (6.3 m for 48 h). Both the number of ticks attracted and the distance traveled to the trap were dependent upon the duration of trap operation (P less than 0.001 for both cases).

Animals↗

The clinical features and prognosis of pseudoseizures diagnosed using video-EEG telemetry.

A total of 110 patients underwent diagnostic evaluation for attacks of uncertain origin by means of video-EEG telemetry and had a diagnosis of pseudoseizures confirmed. Eighty-six patients (78%) were female, mean age of onset 25 years, and mean duration of attacks was 3 years. Many of the patients had erroneously been thought to be suffering from epilepsy. The attacks could be divided into two broad categories: attacks of collapse (one-third) and attacks with prominent motor activity (two-thirds). In some patients, the attacks were associated with incontinence and injury. The differential diagnosis and clinical features of the attacks are described. Additional psychiatric features were present in 52 (47%) patients. Follow-up (for a median 5 years; range, 1 to 14 years) showed that 40% of these patients stopped having pseudoseizures. This favorable outcome was associated with being female, leading an independent life, a formal psychological approach to therapy and counseling, and the absence of coexisting epilepsy, but not with the duration of pseudoepilepsy, prior episodes of pseudostatus, the coexistence of overt psychiatric disease, or the clinical features of the attacks.

Adult↗

Complex partial seizures and small posterior temporal or extratemporal structural lesions: surgical management.

Twenty patients with small, indolent, relatively inaccessible posterior temporal or extratemporal lesions had complex partial seizures presumably related to anterior and inferomesial temporal lobe epileptic activity. All underwent anterior temporal corticectomies, and in six the resection was extended at a second operation. There was sclerosis of mesial temporal structures in seven of the surgical specimens. Two patients became seizure free for more than 2 years; three others showed more than 95% reduction in seizure frequency, and five had moderate (greater than 50%) reduction. While cessation of seizures or improved control may occur following this surgical strategy, the results are strikingly inferior to those obtained when the lesion, as well as the epileptogenic area, can be resected. Review of this group of patients suggests that the lesion should be included in the resection if at all possible.

Adolescent↗

Methods for control of tick vectors of Lyme borreliosis.

During the IVth International Conference on Lyme Borreliosis in Stockholm, 1990, a workshop on control of Lyme disease vectors briefly reviewed: basic ecological principles for tick control; biocontrol of ticks; chemical control, including the use of repellents and use of permethrin-treated rodent nest material; tick control by habitat modification; and reduction of tick host availability. It was concluded that, although much research work remains, Lyme borreliosis is to a large extent a preventable infection. Avoidance of heavily tick-infested areas, personal protection using proper clothing, and prompt removal of attached ticks remain the most effective protective measures. Many other prophylactic measures are available and could be efficiently integrated into schemes to reduce the abundance of vectors. However, since the ecology of the infection varies greatly between different localities it may be necessary to apply different combinations of control methods in different endemic regions.

Animals↗

Visceral leishmaniasis in HIV infection and AIDS: clinical features and response to therapy.

The development of visceral leishmaniasis with atypical features in an AIDS patient, and the recent flurry of reports of visceral leishmaniasis in HIV-infected individuals prompted the review of its manifestations in the 47 reported cases. Splenomegaly, which is almost always a feature of visceral leishmaniasis in the immunocompetent host, was absent in eight. Antibodies to Leishmania donovani, which are present in approximately 95 per cent of immunocompetent patients with visceral leishmaniasis, were absent in 29 of 45 (66 per cent) of HIV-infected patients tested. Nine HIV-positive patients with visceral leishmaniasis did not exhibit a primary clinical response to therapy with antimonials and of those who did show a response, relapse occurred in 13, at a mean 4.5 months after stopping therapy. Seventeen patients are known to have died often in association with respiratory disease; Leishmania was seen in one bronchial lavage specimen and in lung tissue in one post-mortem performed. In order to improve the prognosis of visceral leishmaniasis in HIV-infected patients diagnosis will have to be made earlier, taking account of the atypical features, and treatment will need to be improved, both initially and perhaps also by the use of long-term maintenance therapy.

Acquired Immunodeficiency Syndrome↗

The role of medium-sized mammals as reservoirs of Borrelia burgdorferi in southern New York.

The ability of raccoons (Procyon lotor), striped skunks (Mephitis mephitis) and opossums (Didelphis virginiana) to serve as reservoirs of Borrelia burgdorferi, the spirochetal agent of Lyme disease, was compared with that of white-footed mice (Peromyscus leucopus). Twenty-eight (28) medium-sized mammals and 34 white-footed mice were captured in Westchester County, New York (USA) in summer 1986. Animals were caged over pans of water for 1 to 2 days to recover engorged tick larvae (Ixodes dammini) that detached from the hosts after feeding. With the exception of mice, numbers of engorged tick larvae recovered exceeded those counted during initial examinations of the hosts by 30% (opossums) to nearly 90% (raccoons). Newly-molted nymphal ticks derived from the engorged larvae were examined for the presence of spirochetes by darkfield microscopy. Percentage infection was 5% (n = 22) for ticks from skunks and 14% (n = 191) for ticks from raccoons. None of 24 nymphs from larvae that fed on opossums survived long enough for spirochete examination. By comparison, 40% (n = 72) of nymphs from larvae which fed on white-footed mice were infected. Of the individual hosts from which molted nymphs had fed as larvae, 67% of mice, 33% of skunks, and 55% of raccoons produced spirochete-positive ticks.

Analysis of Variance↗