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Biomedical subjects

L A Magnarelli

Publications and source records attributed to L A Magnarelli.

At least 127 records · Page 7Linked to original sources
PubMed1983

Spirochetes in Ixodes dammini and mammals from Connecticut.

Spirochetes were observed in the midguts of 35% of 147 motile Ixodes dammini from three locations in Lyme and East Haddam, Connecticut. Positive ticks were removed from eastern chipmunks (Tamias striatus), raccoons (Procyon lotor), white-footed mice (Peromyscus leucopus), and a red squirrel (Tamiasciurus hudsonicus). Spirochetes were isolated in fortified Kelly's medium from nine questing or partially engorged I. dammini adults and nymphs and from the bloods of a raccoon and a white-footed mouse. Connecticut isolates from ticks and mammals were serologically indistinguishable from the original Shelter Island, New York strain when cross-tested by immunofluorescence against their mouse antisera. Sera from eight patients diagnosed as having Lyme disease contained antibodies to spirochetes isolated from ticks and mammals. Our finding of serologically and morphologically indistinguishable spirochetes in a raccoon, white-footed mouse and ticks suggests that closely related serotypes are present in wild mammals commonly parasitized by I. dammini, and further supports the claim that a spirochete is involved in the etiology of Lyme disease.

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PubMed1982

Antibodies to spotted fever-group rickettsiae in dogs and prevalence of infected ticks in southern Connecticut.

Blood samples and ticks were obtained from dogs to assess canine exposure to spotted fever-group (SFG) rickettsiae during 1978-1980 in southern Connecticut. Of the 1,576 dog sera screened by microimmunofluorescence. 174 (11.0%) contained specific antibodies at titers greater than or equal to 1:64 against Rickettsia montana (n = 34), R rickettsii (n = 31), R rhipicephali (n = 19), or the unclassified 369-C rickettsia (n = 90). End points greater than or equal to 1:8,192 to R rickettsii and to R rhipicephali were recorded for 6 and 3 sera, respectively. Seropositivity rates from southwestern and southeastern Connecticut were similar (about 11%), with positive sera obtained from each region in nearly all months of the investigation. Rates were between 10% for dogs 2 to 7 years old and 14% for those greater than or equal to 8 years. Eight of 629 Dermacentor variabilis, 1 of 18 Ixodes dammini, and 2 of 3 Amblyomma americanum were positive by direct immunofluorescence for SFG rickettsiae. Thirteen D variabilis contained unidentified, long, bacillus-like organisms that differed from the short, ovoid (coccal) forms typical fo the spotted-fever agent, R rickettsii. With the exposure to infected ticks and production of type-specific antibodies against at least 4 SFG antigens, dogs may serve as suitable enzootic or epizootic indicators of rickettsial activity.

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PubMed1981

Endemicity of spotted fever group rickettsiae in Connecticut.

To compare rickettsial infectivity and seropositivity rates against spotted fever group (SFG) rickettsiae, ticks and wild mammals were collected from three areas where Rickettsia rickettsii was thought to be enzootic in Connecticut during 1978-1979, and from four additional sites (with no reported human cases) between 1976 and 1979. Of the 1,001 Dermacentor variabilis examined by the hemolymph test, 59 (5.9%) contained rickettsia-like organisms; direct immunofluorescence tests verified the presence of SFT rickettsiae in 14 specimens. Prevalence of rickettsiae-infected ticks at Newtown, an area where human cases of Rocky Mountain spotted fever probably originated, was 2.2%. Rates for six other areas ranged between 0 and 6.3%. Isolations included Rickettsia montana from four ticks collected at Branford and Woodbridge, and R. rickettsii (R-like strain) from the blood of an acutely ill person. Microagglutination (MA) tests indicated that 15 (14.9%) of 101 Peromyscus leucopus (white-footed mice) from Newtown had agglutinins in titers greater than or equal to 1:8 against R. rickettsii, whereas five of 92 white-footed mice (5.4%) from Brandord, West Hartford, Woodbridge, and Sharon were considered MA-positive. Indirect microimmunofluorescence tests of Procyon lotor (raccoon) sera revealed antibodies to R. rickettsii in 33 of 69 (47.8%) samples from Newtown and in two of 60 (3.3%) from Guilford. Additionally, 17 raccoons had sera specific to R. montana (n = 8) or to the 369-C rickettsia strain (n = 9). Since rickettsia-positive ticks are high-titered seropositive mammals occurred at widely separated sites in Connecticut there are probably several foci of SFG rickettsiae distributed throughout the D. variabilis range.

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PubMed1981

Human cases of furuncular, traumatic, and nasal myiasis in Connecticut.

Case histories are reported for four persons who had furuncular, traumatic, and nasal myiasis in Connecticut during 1980. Third-stage Sarcophaga sp. and Musca domestica larvae were removed from sores or wounds, a 2nd-stage Cuterebra sp. larva was dislodged from cutaneous tissue, and 3rd-stage larvae of Phaenicia sericata were extracted from nasal membranes. Human exposure to these facultative or obligate dipteran parasites occurred at residences in urban and suburban settings, including a convalescent home and a hospital. Infestations were asymptomatic in three cases, and following removal of larvae, each person recovered without further complications.

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PubMed1981

Raccoon babesiosis in Connecticut, USA: Babesia lotori sp. n.

A species of Babesia which infects raccoons, Procyon lotor, is described and named Babesia lotori. Twelve of 14 raccoons captured from five counties in Connecticut developed parasitemia after splenectomy. Preoperative levels were subpatent or less than 1%. Parasitemia peaked anywhere from less than 5% to 36.6% in splenectomized raccoons, and all but one survived and possessed low infection rates (less than or equal to 3%) at the end of the experiment. An indirect fluorescent antibody test is described and shown to be useful in detecting antibodies to B. lotori. Seropositive raccoons were obtained from six counties. Two, Babesia-free, splenectomized raccoons developed parasitemia with corresponding increases in antibody titers after they were inoculated with infected blood. Antibody titers of naturally infected raccoons following splenectomy either remained stable or increased fourfold. Babesia was observed in three of four young raccoons which had been naturally confined to chimneys. Two of these four young raccoons were infested with a nest-dwelling tick, Ixodes texanus.

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PubMed1980

Canine babesiosis: indirect fluorescent antibody test for a North American isolate of Babesia gibsoni.

A sensitive and reproducible indirect fluorescent antibody test for a North American isolate of Babesia gibsoni was described. In blind tests (coded samples), titer reproducibility was within two 4-fold dilutions and the appropriate positive and negative sera were identified as such. Babesia gibsoni antisera reacted with homologous antigen at one to three 4-fold dilutions greater than with the following heterologous species: B bigemina, B argentina, B equi, Plasmodium falciparum, and P brasilianum. The titer of B canis antiserum to B gibsoni antigen was 1:1,024. low parasitemia (less than 0.01%) of B gibsoni preceded development of minimum significant titer (1:64) by 10 days in a splenectomized dog. Maximum titer was detected 25 days later. In a nonsplenectomized dog, low parasitemia (less than 0.01%) was noted 6 days after injection; it reached 8% at 5 weeks and decreased to and remained below 1% at 7 weeks. A titer of 1:256 occurred at 25 days and increased to 1:65,536 at 18 weeks. Thereafter, it fluctuated to 1:4,096 until the experiment was ended at 24 weeks. organismic antigen retained its reactivity for 5 days at 5 C. This indirect fluorescent antibody test should be useful in the diagnosis of dogs infected with B gibsoni.

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PubMed1979

Canine Babesia new to North America.

A domestic dog residing in New England suffered a fatal febrile illness caused by a Babesia infection. The morphology of these intraerythrocytic protozoa and the range of hosts that could be infected experimentally suggested that the parasite was B. gibsoni. Although this tick-bourne disease is enzootic in wild and domestic Canidae in Africa and Asia, it appears to be new to the Americas.

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PubMed1979

Rocky mountain spotted fever in Connecticut: human cases, spotted-fever group rickettsiae in ticks, and antibodies in mammals.

Three parameters were used in 1976 and 1977 to assess the status of Rocky Mountain spotted fever (RMSF) in Connecticut--compilation and review of clinical data on suspected human cases for the 13-year period 1965--1977, examination of tick tissues for spotted fever-group rickettsiae by the hemolymph test and direct immunofluorescence, and analyses of mammalian sera for antibodies against Rickettsia rickettsii. There were six presumptive RMSF cases which probably originated in Connecticut. Four of these cases occurred in areas where the American dog tick, Dermacentor variabilis, abounds. A total of 2994 ticks were examined by the hemolymph test. Rickettsia-like organisms were observed in 67 (2.9%) of 2330 D. variabilis and two (0.6%) of 351 Ixodes sp. near scapularis. Fewer than one-half of these organisms stained positively with spotted fever-group conjugate. Microagglutination tests on 1093 mammalian sera indicated that eight (16%) of 49 raccoons, 14 (2.6%) of 549 white-tailed deer, eight (1.7%) of 470 white-footed mice, and one of two gray squirrels had agglutinins in titers greater than or equal to 1:8 against R. rickettsii. Spotted fever-group rickettsiae are present at low frequency in inland as well as coastal regions of Connecticut.

Adult↗
PubMed1979

Intraerythrocytic parasites in rodent populations of Connecticut: Babesia and Grahamella species.

A total of 612 Peromyscus leucopus, 11 Microtus pennsylvanicus, 21 Clethrionomys gapperi, and 4 Tamias striatus was collected in Connecticut and examined for Babesia and Grahamella during 1976 and 1977. Babesia antibodies were detected in sera of 9 P. leucopus collected from 4 sites. Babesia parasites were not detected in the blood smears of captured rodents. Subsequent splenectomy and subinoculation of blood from these rodents into susceptible animals failed to induce disease and no Babesia was isolated. Six of 10 P. leucopus inoculated with a Shelter Island, New York strain of B. microti remained infected for 3 1/2 months. Indirect fluorescent antibody titers of experimentally infected P. leucopus ranged from 1:8 to 1:256. Prevalence of Grahamella peromysci infection, as determined from examinations of blood smears of P. leucopus, was 13%. This infection rate is a conservative estimate because parasitemia is difficult to detect in intact animals. Twenty of 58 P. leucopus, taken at 2 sites and with negative blood smears for G. peromysci, developed parasitemia after splenectomy.

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