Biomedical subjects
L A Durden
Publications and source records attributed to L A Durden.
Robert Traub (1916-1996): a bibliography.
Explore the source record for details and available documents.
Illustrated key to nymphs of the tick genus Amblyomma (Acari: Ixodidae) found in the United States.
A dichotomous identification key, with important characters illustrated by scanning electron micrographs, is provided for nymphs of the 9 species of the genus Amblyomma occurring in the United States. Species included are A. americanum (L.), A. cajennense (F.), A. dissimile Koch, A. imitator Kohls, A. inornatum (Banks), A. longirostre (Koch), A maculatum Koch, A. rotundatum Koch, and A. tuberculatum Marx. Notes on the geographical distributions, medical and veterinary importance, and nymphal stage hosts are included for each species.
Some factors affecting infestation of white-tailed deer by blacklegged ticks and winter ticks (Acari:Ixodidae) in southeastern Missouri.
A total of 5,669 ticks of 4 species was collected from 515 hunter killed, white-tailed deer. Odocoileus virginianus (Zimmerman), in southeastern Missouri from 1993 through 1995. The American dog tick, Dermacentor variabilis (Say) (4 adults), the lone star tick, Amblyomma americanum (L.) (57 adults, 2 nymphs), the blacklegged tick, Ixodes scapularis (Say) (3,120 adults), and the winter tick, Dermacentor albipictus (Packard) (2.059 adults, 436 nymphs, 1 larva) were collected. Patterns of adult D. albipictus and I. scapularies infesting deer were analyzed with respect to upland versus lowland habitat, county, and host sex. Prevalence and intensity of infestation by D. albipictus were higher on bucks than does, and a higher infestation prevalence was recorded for this tick on deer from upland than from lowland habitats. Mean intensities for D. albipictus were not significantly different between counties. Prevalence and mean intensity of infestation for I. scapularis were significantly higher on deer from uplands than lowlands and on bucks than does; mean intensities also differed between counties for this tick. Because adjacent populations, as well as the sex of the host, can differ in infestation rates, differences between local populations of I. scapularis should be recognized to optimize tick surveys and population models.
Ectoparasite fauna of the eastern woodrat, Neotoma floridana: composition, origin, and comparison with ectoparasite faunas of western woodrat species.
We collected ectoparasites from eastern woodrats, Neotoma floridana, from 3 sites in the southeastern United States: coastal South Carolina, southeast Georgia, and south-central Georgia. Twelve ectoparasite species were recovered from 47 woodrats in South Carolina (5 ticks, 5 mites, 2 fleas), 13 from 35 woodrats in south-central Georgia (1 tick, 10 mites, 2 fleas), and 4 from a small host sample (7) in southeast Georgia (2 ticks, 1 mite, 1 flea). New state records are established for the listrophorid mite Listrophorus neotomae from both Georgia and South Carolina, the myocoptid mite Myocoptes neotomae from Georgia, and the ceratophyllid flea Orchopeas sexdentatus pennsylvanicus from South Carolina. Different ectoparasites predominated on woodrats at each site with the tick Ixodes minor being the most commonly collected species in South Carolina, the American dog tick Dermacentor variabilis in southeast Georgia, and the chigger Euschoengastia peromysci in south-central Georgia. Most of the 17 species recovered are known to parasitize several species of mammals, especially rodents, and none of them are host specific to N. floridana. However, the fleas Epitedia cavernicola and Epitedia neotomae are host-specific ectoparasites of eastern woodrats in other parts of their range. Also, 1 species of tick, 2 mites, and 3 fleas parasitize eastern woodrats in addition to western woodrats. A similar lack of host specificity is apparent for the few previously documented collections of ectoparasites from eastern woodrats, including 1 detailed survey in Indiana. Conversely, Neotoma spp. woodrats inhabiting western North America are parasitized by a plethora of host-specific ectoparasites including 2 tick species, 5 mites (other than chiggers), 20 chiggers, 2 sucking lice, and 42 fleas. Recognizing that western biotas are typically more speciose than corresponding eastern biotas in North America, we further propose that because eastern woodrats are the most recent and eastern descendants of the ancestral Neotoma stock, (1) some ectoparasite species failed to accompany the eastern woodrat lineage in its eastward dispersals, and (2) there has been insufficient time for a diverse assemblage of ectoparasites to co-evolve with eastern woodrats.
The fleas (Siphonaptera) of Tennessee.
Thirty-three species of fleas are recorded from the state of Tennessee. New state records are reported for two species, the pulicid fleas Euhoplopsyllus glacialis affinis and Pulex simulans. Two species of fleas with catholic feeding habits appear to be especially widespread and abundant in Tennessee. These are the pulicid Ctenocephalides felis which parasitizes cats, dogs, humans, opossums, and other medium to large sized mammals, and the hystrichopsyllid Ctenophthalmus pseudagyrtes which is associated with several species of small mammals, particularly shrews, moles, voles, and native mice. For a southeastern state, Tennessee has a relatively rich flea fauna. The figure of 33 flea species recorded here for Tennessee is higher than documented figures for other southeastern states (17 species for Alabama, 19 for Florida, 20 for Georgia, 12 for Mississippi, 18 for North Carolina, 19 for South Carolina). This is largely because several species with boreal origins inhabit the higher elevations characteristic of the Appalachian Mountains in the eastern part of the state. Although plague is not enzootic as far east as Tennessee, and murine typhus is rare of absent, suitable flea vectors inhabit the state and one abundant flea species, C. felis, is a pest because it feeds on companion animals and humans.
Sucking lice (Anoplura) of mammals of Tennessee.
Twenty-five species of sucking lice are recorded from wild and domestic mammals, including humans, from Tennessee. Collections of 10 of these species (Haematopinus eurysternus, Hoplopleura captiosa, Hoplopleura hirsuta, Hoplopleura oryzomydis, Hoplopleura trispinosa, Linognathus africanus, Linognathus setosus, Linognathus vituli, Neohaematopinus sciuropteri and Polyplax auricularis) represent newly documented state records. Host specificity was exhibited by 22 species of lice with each of these species being recovered from just one mammal species. Louse infestation prevalences are included for large samples of hosts. A host-parasite list for Tennessean sucking lice is included.
Ticks, Lyme disease spirochetes, trypanosomes, and antibody to encephalitis viruses in wild birds from coastal Georgia and South Carolina.
Ticks and blood samples were collected from wild birds mist-netted on St. Catherine's Island, Georgia, and at the Wedge Plantation in coastal South Carolina in 1994 and 1995. Immature stages of 5 species of ixodid ticks were recovered from 10 of 148 (7%) birds belonging to 6 species in Georgia, whereas 6 ixodid species were recovered from 45 of 259 (17%) birds representing 10 avian species in South Carolina. Borrelia burgdorferi sensu lato was isolated from 27 of 120 (23%) screened ticks (Ixodes scapularis and Ixodes minor) recovered from South Carolina birds, but from none of 16 screened ticks removed from Georgia birds. This spirochete was also isolated from 1 of 97 (1%) birds in South Carolina. In 1995, neither eastern equine encephalitis (EEE) virus nor St. Louis encephalitis (SLE) virus was isolated from any of 218 bird sera screened, but serum neutralizing antibodies were found to EEE virus in 4 of 121 (3%) sera and to SLE virus in 2 of 121 (2%) sera from South Carolina. No antibody to either virus was detected in 51 avian sera screened from Georgia. Trypanosomes (probably Trypanosoma avium) were isolated from 1 of 51 (2%) birds from Georgia and from 13 of 97 (13%) birds from South Carolina. Our data suggest that some wild birds may be reservoir hosts for the Lyme disease spirochete and for encephalitis viruses in coastal Georgia and South Carolina and that migrating birds can disperse immature ticks infected with B. burgdorferi.
Fleas and lice parasitizing mammals in Missouri.
Three species of chewing lice, 11 species of sucking lice, and 28 species of fleas are recorded from mammals in Missouri. Of these, seven species of sucking lice (Hoplopleura acanthopus, Hoplopleura hesperomydis, Hoplopleura sciuricola, Neohaematopinus sciuri, Neohaematopinus sciurinus, Neohaematopinus sciuropteri, and Solenopotes ferrisi) and one species of flea (Doratopsylla blarinae) represent new state records. From 1993 to 1995, 773 individual mammals were examined for ectoparasites in southeastern Missouri. One species of chewing louse, 6 species of sucking lice, and 11 species of fleas were recovered from 18 of the 21 mammal species examined. Ctenophthalmus pseudagyrtes was recovered from more mammal species (6) than any other flea species; and the white-footed mouse, Peromyscus leucopus, was parasitized by more flea species (5) than other hosts examined. Except for H. sciuricola, which was recovered from two congeneric species of tree squirrels, each species of louse was confined to a separate host species.
The effect of infection with Lyme disease spirochetes (Borrelia burgdorferi) on the phototaxis, activity, and questing height of the tick vector Ixodes scapularis.
Little is known about the effects of infection with Borrelia burgdorferi, the bacterium that causes Lyme disease, on its tick vectors. The purpose of this study was to determine the behavioural and ecological effects of infection by the bacterium in nymphal and adult black-legged (Ixodes scapularis) ticks. We found that the effects of infection were more pronounced in adults than in nymphs. Compared to uninfected adults, infected adults were less able to overcome physical obstacles, avoided vertical surfaces, were less active and quested at lower heights. Infected nymphs showed increased phototaxis and attraction to vertical surfaces. Infected nymphs also showed trends toward increased questing height and a greater tendency to overcome physical obstacles although these trends were not statistically significant. These altered behaviours in an infected tick may affect survival or pathogen transmission and may reflect kin selection in the bacterial pathogen.
Ixodes (Ixodes) scapularis (Acari:Ixodidae): redescription of all active stages, distribution, hosts, geographical variation, and medical and veterinary importance.
The blacklegged tick, Ixodes (Ixodes) scapularis Say, 1821, is redescribed, based on laboratory reared specimens originating in Bulloch County, Georgia. Information on distribution, host associations, morphological variation, and medical/veterinary importance is also presented. A great deal of recent work has focused on this species because it is the principal vector of the agent of Lyme disease (Borrelia burgdorferi Johnson, Schmidt, Hyde, Steigerwaldt & Brenner) in eastern North America. Its distribution appears to be expanding, and includes the state of Florida in the southeastern United States north to the provinces of Nova Scotia and Prince Edward Island, Canada, west to North and South Dakota, United States, and south to the state of Coahuila, Mexico. Although I. scapularis feeds on at least 125 species of North American vertebrates (54 mammalian, 57 avian, and 14 lizard species), analysis of the U.S. National Tick Collection holdings show that white-tailed deer, Odocoileus virginianus (Zimmermann), cattle, Bos taurus L., dogs, Canis lupus L., and other medium-to-large sized mammals are important hosts for adults as are native mice and other small mammals, certain ground-frequenting birds, skinks, and glass lizards for nymphs and larvae. This tick is a polytypic species exhibiting north-south and east-west morphological clines. Analysis of variance and Student-Newman-Keuls multiple comparisons revealed significant interpopulational variation that is expressed most significantly in the nymphal stage. Nymphs from northern (Minnesota, Massachusetts, Maryland) populations had relatively larger basis capituli with shorter cornua (except Maryland) than southern (North Carolina, Georgia) populations. Midwestern populations (Minnesota, Missouri) differed from eastern populations (Massachusetts, Maryland, North Carolina, Georgia) in idiosomal characters (broader scuta, larger coxae III, and IV). In addition to Lyme disease, this tick is also a primary vector of the agent of human and rodent babesiosis, Babesia microti Franca. Under laboratory conditions it has transmitted the agents of deer babesiosis, Babesia odocoilei Emerson & Wright, tularemia, Francisella tularensis McCoy & Chapin, and anaplasmosis, Anaplasma marginale Theiler. Moreover, I. scapularis can reach pest proportions on livestock, and females can cause tick paralysis in dogs.
Nocturnal questing by adult blacklegged ticks, Ixodes scapularis (Acari: Ixodidae).
Quantitative tick drag samples were taken at various times during the day and night from February through April 1994 on St. Catherines Island or on Sapelo Island, Georgia. For each month, there was no statistical difference between the numbers of adult blacklegged ticks, Ixodes scapularis, collected during any hour of daylight or darkness on St. Catherines Island, Adult I. scapularis also quested during both day and night on Sapelo Island, but on this island significantly more ticks were collected in 1 nocturnal sample during March. Nocturnal questing may partially explain why hosts that are principally nocturnal or that are active during both day and night are often heavily parasitized by adult I. scapularis. This observation could be epidemiologically important with respect to tickborne zoonoses such as Lyme disease and babesiosis.
Ticks parasitizing humans in Georgia and South Carolina.
From 1990 through 1995, 913 ticks removed from 460 human patients in Georgia or South Carolina were identified and recorded. The majority of these specimens (758, 83.0%) were lone star ticks, Amblyomma americanum. One hundred and four (11.4%) American dog ticks Dermacentor variabilis, 36 (3.9%) blacklegged ticks Ixodes scapularis, 9 (1.0%) Gulf coast ticks Amblyomma maculatum, and 6 (0.7%) brown dog ticks Rhipicephalus sanguineus were also recovered. All active stages (larvae, nymphs, and adults) of A. americanum were represented, whereas nymphs and adults of D. variabilis and I. scapularis and only adults of A. maculatum and R. sanguineus were recorded. Compared with data published for other regions in the U.S.A., A. americanum was a much more prevalent parasite of humans in the current survey. Only 1 (3%) of the I. scapularis collected was a nymph. Because these tick species are vectors of zoonotic pathogens or cause tick paralysis in humans, the data have epidemiological significance.
Ticks and fleas of shrews in Appalachian Georgia and North Carolina.
Ticks (Acari: Ixodidae) and fleas (Insecta: Siphonaptera) were recovered from 8 smoky shrews, Sorex fumeus Miller, and 9 northern short-tailed shrews, Blarina brevicauda (Say), trapped at elevations of 720-1,310 m in Macon and Jackson counties in western North Carolina and Union County in northern Georgia from April 1994 to August 1995. The ticks Ixodes angustus Neumann and Ixodes woodi Bishopp, and the flea Corrodopsylla curvata (Rothschild), were recovered from smoky shrews. The same 2 tick species, in addition to the fleas, Ctenophthalmus pseudagyrtes Baker and Doratopsylla blarinae Fox, were recovered from northern short-tailed shrews. New state records for I. angustus from Georgia and I. woodi from North Carolina are established.
Bot fly (Cuterebra fontinella fontinella) parasitism of cotton mice (Peromyscus gossypinus) on St. Catherines Island, Georgia.
From February 1993 through October 1994, 382 cotton mice (Peromyscus gossypinus) were live-trapped and examined for bot fly (Cuterebra fontinella fontinella) larvae. Thirty-nine (10%) of the mice were parasitized by a total of 44 bot fly larvae. All bots were situated in the inguinal or lower abdominal region of the mice. Monthly data strongly suggested that this bot is bivoltine at this latitude with distinct summer and winter population peaks. Prevalence of parasitism was highest in June 1994 when 56% of 16 mice examined were infested with a mean intensity of 1.3 bots. Adult flies were successfully reared from 10 bots that exited from mice; the time period (58-98 days, mean = 79.5) that these specimens spent in the soil as pupae further supports the contention that C. f. fontinella is bivoltine on St. Catherines Island.
Fleas (Siphonaptera) of cotton mice on a Georgia barrier island: a depauperate fauna.
From February 1993 through October 1994, 382 cotton mice Peromyscus gossypinus were live-trapped and examined for fleas on St. Catherines Island, Liberty County, Georgia. Orchopeas leucopus was the only species of flea collected, with an overall prevalence of 27% and a mean intensity of 3.8. This flea was more abundant on cotton mice during the cooler months, with peak infestation indices recorded in March 1993 and in January 1994. Five species of fleas (Polygenis gwyni, Stenoponia americana, Ctenophthalmus pseudagyrtes, Peromyscopsylla scotti, and O. leucopus) were collected from 29 cotton mice live-trapped in adjacent mainland localities during the same period. The depauperate flea fauna of cotton mice on St. Catherines Island suggests that either the original colonizing cotton mice were infested by only 1 species of flea (O. leucopus) and that no subsequent invasions of cotton mouse fleas have occurred, or that other cotton mouse fleas cannot establish on the island.
Experimental transmission of Langat (tick-borne encephalitis virus complex) virus by the soft tick Ornithodoros sonrai (Acari: Argasidae).
Laboratory studies determined that the soft tick Ornithodoros sonrai Sautet & Witkowski is a competent vector of Langat (tick-borne encephalitis virus complex) virus. When ticks fed on suckling mice having a mean viremia of 10(7.2) plaque-forming units per ml, 52% (n = 208) became infected, and 84% (n = 87) of the infected ticks transmitted virus by bite when fed individually on suckling mice > or = 27 d after the infectious blood meal. Overall, 79 of 184 (43%) of ticks exposed to the original viremic mice individually transmitted virus by bite when tested up to 351 d after the infectious blood meal. In addition, ticks transmitted virus both transstadially and transovarially. Some ticks that transmitted virus during their first transmission attempt were retested. These ticks transmitted virus during 81 (99%) of 82 refeeding attempts, including ticks that transmitted virus 512 d after the initial infectious meal. Therefore, Ornithodoros spp. should be considered as potential vectors of Langat and other tick-borne encephalitis viruses.
Ectoparasites of opossums and raccoons in southeastern Georgia.
Twelve species of ectoparasites (four fleas, three ticks, three chiggers, one macronyssid mite, and one atopomelid mite) were recovered from 42 opossums, Didelphis virginiana Kerr, live-trapped from September 1992 through April 1994 in southeastern Georgia. The fleas, Ctenocephalides felis (Bouché) (prevalence = 19%) and Polygenis gwyni (C. Fox) (36%); the ticks, Dermacentor variabilis (Say) (40%) and Ixodes scapularis Say (19%); and the macronyssid mite, Ornithonyssus wernecki (Fonseca) (21%), exhibited the highest infestation prevalences on opossums. The atopomelid mite, Didelphilichus serrifer Fain, and the chigger mite Leptotrombidium peromysci Vercammen-Grandjean & Langston, both ectoparasites of opossums, are reported from Georgia for the first time. Six species of ectoparasites (one chewing louse, four ticks, and one macronyssid mite) were collected from 58 raccoons, Procyon lotor (L.), examined between October 1992 and September 1993 in the same region. The chewing louse, Trichodectes octomaculatus Paine (prevalence = 24%); and the ticks, Amblyomma americanum (L.) (69%), D. variabilis (55%), and Ixodes texanus Banks (24%), exhibited the highest infestation prevalences on raccoons. Three species of ticks, A. americanum, D. variabilis, and I. scapularis, were the only ectoparasites recovered from both host species. Several of the ectoparasites collected are proven vectors of pathogenic agents that affect humans and animals.