To determine which arthropods should be targeted for control should Rift Valley fever virus (RVFV) be detected in North America, we evaluated Culex erraticus (Dyar and Knab), Culex erythrothorax Dyar, Culex nigripalpus Theobald, Culex pipiens L, Culex quinquefasciatus Say, Culex tarsalis Coquillett, Aedes dorsalis (Wiedemann), Aedes vexans (Meigen), Anopheles quadrimaculatus Say, and Culicoides sonorensis Wirth and Jones from the western, midwestern, and southern United States for their ability to transmit RVFV Female mosquitoes were allowed to feed on adult hamsters inoculated with RVFV, after which engorged mosquitoes were incubated for 7-21 d at 260C, then allowed to refeed on susceptible hamsters, and tested to determine infection, dissemination, and transmission rates Other specimens were inoculated intrathoracically, held for 7 d, and then allowed to feed on a susceptible hamster to check for a salivary gland barrier When exposed to hamsters with viremias > or =10(88) plaque-forming units/ml blood, Cx tarsalis transmitted RVFV efficiently (infection rate = 93%, dissemination rate = 56%, and estimated transmission rate = 52%) In contrast, when exposed to the same virus dose, none of the other species tested transmitted RVFV efficiently Estimated transmission rates for Cx erythrothorax, Cx pipiens, Cx erraticus, and Ae dorsalis were 10, 8, 4, and 2%, respectively, and for the remaining species were < or = 1% With the exception of Cx tarsalis and Cx pipiens, all species tested had moderate to major salivary gland barriers None of the C sonorensis became infected and none of the An quadrimaculatus tested transmitted RVFV by bite, even after intrathoracic inoculation, indicating that these species would not be competent vectors of RVFV Although Ae vexans from Florida and Louisiana were relatively efficient vectors of RVFV, specimens of this species captured in Colorado or California were virtually incompetent, illustrating the need to evaluate local population for their ability to transmit a pathogen In addition to laboratory vector competence, factors such as seasonal density, host feeding preference, longevity, and foraging behavior should be considered when determining the potential role that these species could play in RVFV transmission

/pdf/potential-for-north-american-mosquitoes-diptera-culicidae-to-3yxussenqp.pdf

Potential for North American Mosquitoes (Diptera: Culicidae) to Transmit Rift Valley Fever Virus

...................................... 2 Resumen ....................................... 2 Introduction ....................................... 3 Acknowledgments ....................................... 4 Materials and Methods ....................................... 4 Specimens ....................................... 4 Measurements ....................................... 4 Age Criteria ....................................... 5 Karyotypes ..............................................5 Multivariate Statistics .............. ............................. 5 Gazetteer ........................................... 5 The Genus ........................................... 11 Sigmodon Say and Ord ..................................................... 11 Phylogenetic Relationships ....................... .................... 14 Variation Within and Among the South American Species ........... .............. 15 Qualitative External Characters ....................... ................ 15 External Dimensions ....................................... 16 Qualitative Craniodental Characters ....................................... 16 Craniodental Dimensions ........... .......................................... 21 Species Accounts ...................... 26 Sigmodon hispidus Say and Ord ...................... 26 Sigmodon alstoni (Thomas) ...................... 30 Sigmodon peruanus J. A. Allen ...................... 34 Sigmodon inopinatus Anthony ...................... 36 1 Assistant Curator, Department of Mammalogy, American Museum of Natural History. Copyright © American Museum of Natural History 1992 ISSN 0003-0082 / Price $6.50 AMERICAN MUSEUM NOVITATES Natural History...................................................... 37 Species Descriptions........37 Sp ie ~~~~~~ Dsp os............................................... 3 Summary, Comparisons, and Discussion ............. .......................... 46 Biogeography .................................................... 47 Intercontinental Dispersal .................................................... 47 Nonforest Mammal Faunas and South American Paleohabitats ...... ............. 49 References ..................................................... 50 Appendix: List of Measured Specimens ................ .......................... 55

A revision of the South American species of Sigmodon (Mammalia, Muridae) : with notes on their natural history and biogeography. American Museum novitates ; no. 3050

The ontogenetic threshold related to the large size difference between heteromorphic larva and post-larva has inevitably led to larval parasitism and regression of nymphal instars in trombiculid mites. It is most likely that mammals are primary hosts of trombiculid larvae, whereas the use of other terrestrial vertebrates as hosts arose later. An association with a host takes only a short time from the entire life cycle of a trombiculid mite; a mite spends the rest of its life as a free-living soil-dweller. As a result, host selection by a trombiculid larva is determined mainly by habitat distribution of a host rather than by its taxonomic affinity.

Taxonomy, life cycles and the origin of parasitism in trombiculid mites

A checklist of the family Trombiculidae and Leeuwenhoekiidae is presented, containing 63 species in 30 genera of chiggers from 80 different hosts and 146 localities in Brazil. The type locality and depository are provided, including new locality and host records for the country.

https://zookeys.pensoft.net/lib/ajax_srv/article_elements_srv.php?action=download_pdf&item_id=22675

A checklist of chiggers from Brazil, including new records (Acari: Trombidiformes: Trombiculidae and Leeuwenhoekiidae).

This study concerns the patterns of parasitism by the larvae of Eutrombicula alfreddugesi (Oudemans, 1910) on three species of Tropidurus Wied, 1820 from Cerrado habitats of Central Brazil: T oreadicus Rodrigues, 1987 (n = 97), T itambere (n = 85) and T torquatus (Wied, 1820) (two samples n = 75, n = 23) The highest prevalence value was observed in T itambere (882%), followed by T oreadicus (876%), and T torquatus (173% and 652%) The most important sites of infestation were the mite pockets and skin folds, especially on the neck and inguinal region Tropidurus itambere Rodrigues, 1987 was the most heavily parasitized species (mean intensity of infestation: 3667 ± 4109), followed by T oreadicus (1538 ± 2108), and T torquatus from Unai, Minas Gerais (1213 ± 2109) The lowest intensity of infestation was found in T torquatus from urban and periurban areas of Brasilia, Distrito Federal (197 ± 543) The analysis did not indicate differences in intensity of infestation between sexes for any of the species Differences in the patterns of parasitism among the three lizard species may be related to the morphological and numerical variation of the skin folds (especially mite pockets), to the degree of conservation of the host's habitats, and to selective processes related to reduction of damage to the host's bodies, to the evolution of mechanisms of decreasing illness transmission by parasites, or even to some behavioral traits of the lizards

http://www.scielo.br/pdf/rbzool/v23n4/05.pdf

Patterns of parasitism by Eutrombicula alfreddugesi (Oudemans) (Acari, Trombiculidae) in three species of Tropidurus Wied (Squamata, Tropiduridae) from Cerrado habitat of Central Brazil

Detailed or summarized records of 136 species in 38 genera with a key to the latter are provided. Of 86 described forms, 49 are new for Venezuela; the remaining undescribed taxa are coded for purposes of this report. A classified host-parasite list is appended.

/pdf/a-list-of-venezuela-chiggers-particularly-of-small-mammalian-458e8tqhkc.pdf

A list of Venezuela chiggers, particularly of small mammalian hosts (Acarina: Trombiculidae)

The genus Eutrombicula in Venezuela (Acarina: Trombiculidae).

Neotropical representatives of the subfamily Leeuwenlioekinae are reviewed. The genus Odontacarus comprises 66 percent of the chiggers examined, and 82 percent of this genus were identified as O. tuhercularis (Brennan). The following genera are redescribed: Albeckia Veracammen-Grandjean and Watkins, Leeuwenhoekia Oudemans, Odontacarus Evving, Sasacarus Brennan and Jones, Wagenaaria Brennan, and Whartonia Ewing. New taxa are: Odontacarus comosus comosus, O. c. novemsetus, O. dienteslargus, O. pugnosus, O. schoenesetosus, O. sunnianae, O. tiptoni, O. tuherculohirsutus, O. vanderhammeni, O. vergrandi, Sasacarus furmani panamensis, and Whartonia angidaicuta. Odontacarus ficldi Brennan and Jones, 1961, and O. catjolargoensis Brennan, 1959, are synonymized under O. tuhercularis Brennan, 1952. Keys to genera and species are provided.

/pdf/the-subfamily-leeuwenhoekinae-in-the-neotropics-acarina-d7rox1ldfk.pdf

The subfamily Leeuwenhoekinae in the Neotropics (Acarina: Trombiculidae)

Intercutestrix is redescribed, and the new species I. exigua off Proechimys semispinosus and Sigmodon hispidus, Venezuela, I. incomitata off Hoplomys gymnurus, Colombia, and I. pisinna off Proechimys guyannensis, Venezuela, are described. A key to the 5 included species is given. Three new species of the Neotropical intradermal genus Intercutestrix have prompted a generic redescription and assay of promising structural features for ready identification of the minute larvae. Contributing to this study are two species (I. exigua and I. pisinna) collected in Venezuela under the supervision of Dr. Charles 0. Handley, Smithsonian Institution, and Dr. Vernon J. Tipton, Brigham Young University, and one species (I. incomitata) collected in Colombia by Mr. Kjell von Sneidem under the direction of the Field Museum of Natural History. Intercutestrix Brennan and Yunker Intercutestrix Brennan and Yunker, 1966, p. 237. Neotropical trombiculine larvae, intradermal parasites of small mammals, principally rodents of the family Echimyidae. Broad ellipsoidal to subcircular when engorged. Scutum arcuate, considerably wider than long, with shallow sinuous margins. Five scutal setae, anteroand posterolaterals approximate, the latter far anterior to the sensillary bases. Sensillae caducous, known only in one specimen of I. mondolfii where they are broad obovate and moderately setulose. Eyes minute, 2/2 in an indistinct plate, the posterior pair sometimes evanescent. Cheliceral blade small with tricuspid cap. Galeal seta nude. Palpal tibial claw slender, trifurcate; palpal tarsus with 4 branched setae and a tarsala. Leg segmentation 7-6-6; legs with 2 genualae I, no genuala II and III, a tibiala Received for publication 2 July 1973. * This work was supported in part by Department of the Army Contract DA-49-193-MD-2788 with the Smithsonian Institution (Ecology and distribution of mammalian ectoparasites, arboviruses, and their hosts in Venezuela). t U. S. Department of Health, Education, and Welfare, Public Health Service, NIH, NIAID, Rocky Mountain Laboratory, Hamilton, Montana 59840. $ Department of Zoology, Brigham Young University, Provo, Utah 84601. III, no mastisetae, a suband abbreviate parasubterminala, microtarsala I lateroproximad of tarsala I; coxae unisetose. Type species: Euschongastia tryssa Brennan and Jones, 1961. Referred species: Intercutestrix mondolfii Brennan and Yunker, 1969, I. exiguia sp. n., I. incomitata sp. n., and I. pisinna sp. n. Species of Intercutestrix seem to prefer rodent hosts of the family Echimyidae, particularly of the genus Proechimys, although they have been recorded from other rodents and opossums. The minute larvae are rather elusive because of their intradermal habitat where they occur singly, almost completely enclosed in a keratinous cyst, and are found ventrally on the host only by thorough and specific examination (Brennan and Yunker, 1969). Consequently, samples resulting from general chigger collecting are most often small and inadequate for precise and conclusive taxonomic study. Disregarding other structural characters, the five included species are separable by form, size, and arrangement of dorsal setae. The scutum, in the almost invariable absence of sensillae, and setation of the appendages are not remarkable, and offer little aid in specific identification. Figures of scutum and specialized setae of legs were given by Brennan and Jones (1961) for I. tryssa and by Brennan and Yunker (1969) for it and I. mondolfii. Thus, an illustration of scutum and specialized leg setae for only one new species, I. exigua, will suffice here. Key to larvae of Intercutestrix 1. Second posthumeral row with 10 setae (Peru) -.-. --------.-.......tryssa Second posthumeral row with 6 setae .---2 2. Palpal setal formula B/B/BBB, dorsal setal formula begins 2-10 (Colombia) ----)-----...--...... -. .......incomitata

Endoparasitic chiggers. 8. The intradermal genus Intercutestrix Brennan and Yunker, 1966, and three new species (Acarina: Trombiculidae).

Loomisia gen. n. is described to receive Euschoengastia desmodus Brennan and Dalmat, 1960 (type species), Trombicula sprocssi Brennan, 1965, T. univari Brennan, 1965, and 3 new species from Venezuela, L. alcithoae off Carollia sp., Barinas, L. bulbocalcar, holotype off Peropteryx kappleri, Carabobo, and L. yunkeri, holotype off P. kappleri, Bolivar. A synoptic key to the six species is included. Loomis (1969), in recording Euschoengastia desmodus off bats from Yucatan, noted that it, as well as the allied bat chiggers Trombicula sprocssi and T. univari from southwestern United States were misplaced generically and that these three belong to an unnamed genus. The recent discovery of three new species on bats in Venezuela, clearly of this same group, has prompted the erection of a new genus Loomisia and a resume of the six species assigned to it. Unless otherwise stated, all collections which provide new records were made by personnel under the supervision of Dr. Charles O. Handley, Smithsonian Institution, and Lt. Col. Vernon J. Tipton, U. S. Army (retired), now Brigham Young University. The new genus is named for Dr. Richard B. Loomis, Department of Biology, California State College, Long Beach, in recognition of his many significant contributions both in research and in students to the science of chig-

Jack T. Reed

Papers

A list of Venezuela chiggers, particularly of small mammalian hosts (Acarina: Trombiculidae)

The genus Eutrombicula in Venezuela (Acarina: Trombiculidae).

The subfamily Leeuwenhoekinae in the Neotropics (Acarina: Trombiculidae)

Endoparasitic chiggers. 8. The intradermal genus Intercutestrix Brennan and Yunker, 1966, and three new species (Acarina: Trombiculidae).

Loomisia gen. n. with descriptions of three new venezuelan species (Acarina: Trombiculidae).