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Biomedical subjects

L A Magnarelli

Publications and source records attributed to L A Magnarelli.

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

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PubMed1986

Culturing Borrelia burgdorferi from spleen and kidney tissues of wild-caught white-footed mice, Peromyscus leucopus.

Borrelia burgdorferi was isolated most frequently from tissue of spleen (n = 13) and kidney (n = 10) and less often from blood (n = 5) of wild-caught Peromyscus leucopus. Prevalence of infection tended to be highest at sites where Lyme disease was most common (e.g., 5 of 6 mice were positive in East Haddam, Connecticut). Spirochetes were not isolated in Danbury or New Hartford, areas where this malady is rare. However, in Fairfield, where the disease is also uncommon, 4 of 9 mice were infected. Larval and nymphal I. dammini, containing borreliae, parasitized P. leucopus at all sites where B. burgdorferi was cultured from mice. Borreliae were also detected in D. variabilis feeding on hosts at two of the sites. P. leucopus appears to be an excellent animal to identify focal areas of B. burgdorferi.

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PubMed1986

Involvement of birds in the epidemiology of the Lyme disease agent Borrelia burgdorferi.

Borrelia burgdorferi, the causative agent of Lyme disease, was isolated from the liver of a passerine bird, Catharus fuscescens (veery), and from larval Ixodes dammini (tick) feeding on Pheucticus ludovicianus (rose-breasted grosbeak) and Geothlypis trichas (common yellowthroat). In indirect immunofluorescence antibody tests, isolates reacted with polyclonal and monoclonal (H5332) antibodies. Studies on the DNA composition of the veery liver isolate and the strain cultured from an I. dammini larva indicated that both were B. burgdorferi and not Borrelia anserina or Borrelia hermsii. The veery liver isolate infected hamsters and a chick. In contrast, B. anserina infected chicks but not hamsters. B. burgdorferi is unique among Borrelia spp. in being infectious to both mammals and birds. We suggest that the cosmopolitan distribution of B. burgdorferi may be caused by long-distance dispersal of infected birds that serve as hosts for ticks.

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PubMed1986

Peromyscus leucopus and Microtus pennsylvanicus simultaneously infected with Borrelia burgdorferi and Babesia microti.

Borrelia burgdorferi, the etiologic agent of Lyme disease, and Babesia microti, the causative agent of human babesiosis, were isolated from 71 and 57%, respectively, of 14 specimens of Peromyscus leucopus and Microtus pennsylvanicus collected from Prudence and Patience Islands, R.I. Both pathogens were isolated from five individual rodents. The presence of these two infectious organisms in the same mammal suggests that individual larval Ixodes dammini may ingest both pathogens and subsequently transmit them in the nymphal stage.

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PubMed1986

Rickettsia rickettsii and Rickettsia montana from Ixodid ticks in Connecticut.

Dermacentor variabilis, infected with spotted fever group rickettsiae, parasitized 8 of 70 raccoons captured in Newtown, Connecticut. The spotted fever agent, Rickettsia rickettsii, was isolated and identified from 4 adult D. variabilis and from 1 nymphal Ixodes texanus removed from raccoons. This verifies the presence of this etiologic agent in ticks in an area where 6 people had clinical signs and symptoms of Rocky Mountain spotted fever (RMSF) and antibodies to R. rickettsii. These are the first isolations of R. rickettsii from D. variabilis in southern New England and the first identified rickettsiae from I. texanus. No rickettsiae were isolated from Ixodes muris or I. cookei. Rickettsia montana was recovered in Vero cell culture from a D. variabilis collected in East Haddam, Connecticut where RMSF is not known to be prevalent.

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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.

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PubMed1985

Borreliosis in dogs from southern Connecticut.

Blood samples were obtained from dogs in tick-infested regions of southern Connecticut to assess canine exposure to Borrelia burgdorferi, the etiologic agent of Lyme disease in human beings. An indirect fluorescent antibody test detected immunoglobulin (Ig)M antibodies at titers of 1:64 to 1:512 in 22 of 84 serum samples previously shown to be positive with a polyvalent rabbit anti-dog total Ig conjugate. Analyses of paired serum samples from 20 seropositive dogs revealed temporal differences in titers; changes occurred during brief (1 month) or extended (greater than 4 years) sampling periods. Clinical records for 52 seropositive dogs indicated a history of intermittent lameness in 19 of these. Limb/joint disorders typically developed in dogs without IgM antibodies, suggesting manifestation during later phases of illness. A microscopic-agglutination test was used to assess cross reactivity between B burgdorferi and 20 serovars of Leptospira interrogans and biflexa. Analyses of 63 dog serum specimens with antibodies to B burgdorferi and a series of reference rabbit sera revealed minor antigenic relatedness. There was geographic clustering of dogs with antibodies to B burgdorferi in areas of south-central and southeastern Connecticut, where human Lyme disease also occurs.

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PubMed1985

Identification of endemic foci of Lyme disease: isolation of Borrelia burgdorferi from feral rodents and ticks (Dermacentor variabilis).

Borrelia burgdorferi, the etiological agent of Lyme disease, was isolated from the blood, kidneys, spleens, eyes, or livers of white-footed mice (Peromyscus leucopus) (n = 19 of 22) and from the blood, kidneys, or spleens of eastern chipmunks (Tamias striatus) (n = 2 of 2) captured at three foci for Lyme disease in eastern Connecticut. These bacteria were cultured most frequently from spleens (n = 19) and kidneys (n = 15). B. burgdorferi persisted in one mouse for at least 60 days. One spirochetemic mouse had infected Ixodes dammini and Dermacentor variabilis larvae attached, suggesting that these ticks may have acquired spirochetes from the host. Spirochetes isolated from P. leucopus, T. striatus, and D. variabilis larvae were serologically and genetically indistinguishable from reference B. burgdorferi isolates. We conclude that isolation of spirochetes from feral rodents is a method for identifying endemic areas of Lyme disease.

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PubMed1985

Spotted fever group rickettsiae in immature and adult ticks (Acari: Ixodidae) from a focus of Rocky Mountain spotted fever in Connecticut.

Immature and adult ixodid ticks were collected during 1983 and 1984 in Newtown, Connecticut, an area endemic for Rocky Mountain spotted fever (RMSF), to determine prevalence of infection by spotted fever group (SFG) rickettsiae. Direct fluorescent-antibody (FA) staining revealed SFG organisms in 6 (1.8%) of 332 Dermacentor variabilis larvae, 5 (7.8%) of 64 D. variabilis nymphs, and in 2 (40%) of 5 Ixodes cookei nymphs removed from small- and medium-sized mammals. Hemolymph tests detected rickettsia-like organisms in 15 (8.8%) of 170 D. variabilis adults; 8 specimens retested by direct FA were negative. In contrast, hemocytes from 5 (8.6%) of 58 Ixodes texanus females contained organisms that stained positively in both hemolymph and direct FA tests. An indirect microimmunofluorescence test identified specific antibodies to Rickettsia rickettsii, the etiologic agent of RMSF, in serum samples from a chipmunk, raccoons, and white-footed mice. Results indicate that immature or adult ticks of at least three species may be involved in the maintenance and transmission of SFG rickettsiae at Newtown.

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PubMed1984

Comparison of an indirect fluorescent-antibody test with an enzyme-linked immunosorbent assay for serological studies of Lyme disease.

An enzyme-linked immunosorbent assay was compared with an indirect fluorescent antibody test for its ability to detect antibodies to the Lyme disease spirochete in sera of naturally infected humans, dogs, and white-footed mice and experimentally infected Swiss mice. Ninety-five percent of the total 123 sera analyzed reacted similarly in both tests. For 36 human sera, the correlation coefficient (r = 0.47) for logarithmic transformations of indirect fluorescent antibody and enzyme-linked immunosorbent assay titers was significant at P less than 0.01. Within each mammalian species, mean titers for indirect fluorescent antibody and enzyme-linked immunosorbent assay antibodies were within three-fold. Comparisons of different naturally infected mammals revealed relatively higher average titration endpoints in both tests for patients with Lyme disease. Human sera also had the widest range of titers. Both methods proved satisfactory for serological confirmation of prior spirochetal infections.

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PubMed1984

Antibodies to Rickettsia rickettsii in Peromyscus leucopus from a focus of Rocky Mountain spotted fever in Connecticut.

During 1980-1982, white-footed mice (Peromyscus leucopus) were captured in Newtown, Connecticut, an area where Rickettsia rickettsii, the etiologic agent of Rocky Mountain spotted fever, is thought to be enzootic. An indirect microimmunofluorescence test identified specific antibodies to this organism in 16 of 237 (7%) sera: titration end points for 14 samples were relatively high (1:128-1:2048). Antibodies were detected in mice during 1980 and 1981 with monthly prevalences varying from 8 to 22%. These results suggest that P. leucopus may be involved in the ecology of R. rickettsii and that these rodents can be included along with other mammals to monitor spotted fever rickettsial infections in nature.

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PubMed1984

Antibodies to spirochetes in white-tailed deer and prevalence of infected ticks from foci of Lyme disease in Connecticut.

White-tailed deer (Odocoileus virginianus) were examined for the tick, Ixodes dammini, and sera were analyzed for antibodies to spirochetes during 1982. Of the 323 animals inspected in four areas endemic for Lyme disease, 188 (58%) had adult ticks; parasitism ranged from 43% at Haddam to 82% at East Lyme. Direct and indirect fluorescent antibody tests detected spirochetes in 18 of 133 (14%) ticks. Indirect immunofluorescence tests revealed antibodies at titers of 1:64-1:4,096 to this bacterium in 93 (28%) of the 332 sera assayed. There is a close correlation among the distribution of spirochete-infected I. dammini, deer with antibodies, and human cases of Lyme disease.

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