Vegetation structure influences the burden of immature Ixodes dammini on its main host, Peromyscus leucopus

To determine whether the relative abundance of immature Ixodes dammini (the vector of Lyme disease and human babesiosis) is related to habitat structure, we examined tick burdens on their main host, the white-footed mouse (Peromyscus leucopus), in 4 structurally diverse sites on Great Island, Massachusetts, USA. Vegetation structure at each site was quantified with respect to 25 habitat variables. Principal components analysis was used to reduce this set of habitat variables to seven new and orthogonal variables. Immature tick abundance varied widely among grids. Regression analysis of tick burdens on the habitat principal components showed that larval burdens were related strongly to the density of woody vegetation and negatively to herbaceous vegetation. Nymphal burdens were related negatively to herbaceous vegetation, but the relationship was not as strong as in the case of larvae. An experimental reduction in the abundance of white-tailed deer (Odocoileus virginianus), the main host of adult ticks, substantially reduced tick burdens and altered their relationships to habitat structure. Nymphal burdens were unrelated to habitat structure following deer removal. Manipulating habitat structure may have utility as a control strategy against this important vector.

Clustering of host-seeking nymphal deer ticks (Ixodes dammini) infected by Lyme disease spirochetes (Borrelia burgdorferi)

In areas where the agent of Lyme disease is intensely enzootic, the mouse reservoirs may be universally infected. Because a large proportion of the vector tick population appears to feed upon these hosts, the prevalence of infection in the vectors should approach 100%. However, infection in host-seeking nymphal ticks in nature rarely exceeds 40%. To help reconcile this apparent paradox, we examined whether estimates of prevalence might differ if we did not assume that infected ticks are randomly or uniformly distributed within a site. Nymphal Ixodes dammini were collected by dragging a series of 10-meter replicates within an intensely enzootic site. Estimates of the prevalence of spirochetal infection, based upon the monthly means of individual 10-meter collections, were then compared with estimates derived by pooling all samples. Host-seeking ticks tended to cluster. The Lyme disease spirochete was present in 15.6% of 469 pooled ticks. When the prevalence estimate was based solely on ticks in clusters that contained one or more infected ticks, however, at least 50% of the ticks were infected. We conclude that nymphal deer ticks infected by Lyme disease spirochetes tend to aggregate spatially in nature, and that prevalence estimates based upon a mean value for pools may be misleading.

Ectoparasites of the blackbuck antelope (Antilope cervicapra)

Fifty-two free-ranging blackbuck antelope (Antilope cervicapra) from Texas were examined for ectoparasites. Two species of sucking lice (Anoplura), one species of chewing louse (Mallophaga), one species of louse fly (Diptera), and three species of ticks (Acari) were found. This is the first report of the anoplurans Linognathus cervicaprae and L. pithodes from the Western Hemisphere. The southern deer ked (Lipoptena mazamae), the winter tick (Dermacentor albipictus), and the rabbit tick (Haemaphysalis leporispalustris) are reported from blackbuck for the first time. The lone star tick (Amblyomma americanum) and the mallophagan (Damalinia cornuta cornuta) were reported previously from blackbuck in Texas, the latter species under the name Tricholipeurus balanicus balanicus.

Tick sweep: modification of the tick drag-flag method for sampling nymphs of the deer tick (Acari: Ixodidae)

We describe a version of the standard tick drag-flag modified for use in close-growing and tangled vegetation, as well as under ornamental shrubbery and fallen branches. Two major features of the sweep are: (1) it allows the user to remain upright with the flag parallel to the ground, thus sampling effectively beneath low and fallen branches and around shrubs, as well as capturing host-seeking ticks in advance of the operator; and (2) the use of a flannel rubberized-laminate fabric (crib sheet) for the flag that is snag-proof and highly durable in dense and thorny vegetation. In simultaneous 100-m samples, the sweep was as effective as the 1-m standard tick drag for capturing nymphs of the deer tick, Ixodes dammini Spielman, Clifford, Piesman & Corwin, where understory vegetation was sparse, but was twice as effective in dense vegetation, capturing significantly more I. dammini nymphs. The sweep also captured nymphs of the American dog tick, Dermacentor variabilis (Say); rabbit tick, Haemaphysalis leporispalustris (Packard); and lone star tick, Amblyomma americanum (L.).

Ectoparasites from river otters in Pennsylvania

Twenty-three livetrapped and two trapper-caught river otters (Lutra canadensis) from northeastern Pennsylvania (USA) were examined for ectoparasites immediately after their captures during 1981 to 1985. Ectoparasites were collected from both trapper-caught otters, but from only one livetrapped otter. One species of tick (Ixodes cookei) and one flea (Oropsylla arctomys) were collected.

Parasite burdens and host susceptibility of Zebu and N'Dama cattle in village herds in Gambia

Helminth and tick burdens of N'Dama cattle kept in village herds were compared with parasite burdens in Zebu cattle introduced into the same herds. The animals were monitored regularly for tick and helminth burdens, and blood samples were examined for differential white cell counts. The Zebu were found to have significantly higher numbers of endo- and ectoparasites. The N'Dama had significantly higher levels of circulating eosinophils than the Zebu during peak parasite burdens. No difference in antibody levels to Amblyomma variegatum infestation could be detected between the two breeds. It is suggested that observed differences in susceptibility to endo- and ectoparasites between the two breeds cannot be totally attributed to environmental naivety of the Zebu, but must be partially owing to enhanced innate resistance factors in the N'Dama.

First record of Ixodes brunneus in Kansas

A single specimen, a partially engorged female, of Ixodes brunneus was recovered from a common grackle (Quiscalus quiscula) in Butler County, near El Dorado, Kansas (USA). The discovery of this tick in Kansas represents a new state record.

Tick infestations of white-tailed deer in Alabama

Four species of ticks were collected from 537 white-tailed deer (Odocoileus virginianus), examined during the hunting seasons (November to January) of 1988-89 and 1989-90 at selected locations in Alabama (USA). Ixodes scapularis was the most common tick recovered (2,060 specimens) and infested 54% of the deer. Dermacentor albipictus was the second most frequent tick (1,253 specimens) and infested 15% of the deer. Amblyomma americanum was the third most frequent tick (315 specimens) and infested 24% of the deer; this was the only species of tick collected from deer at all sampling locations. Amblyomma maculatum was an infrequent parasite (five specimens) and infested only 1% of the deer; this tick species was only recorded during the 1989-90 season. Year-to-year and geographical differences in tick infestation parameters were noted. The data are compared with those reported for previous surveys of ticks infesting white-tailed deer in Alabama and adjacent states.

Ticks (Ixodidae) parasitizing humans in four provinces of north-western Argentina

In four provinces of north-western Argentina (Catamarca, Jujuy, Salta and Tucumán), between March 1976 and March 1990, 514 ticks were found on humans. They were identified as Rhipicephalus sanguineus group (1 male), Boophilus microplus (6 male, 1 female), Amblyomma parvum (9 male, 13 female), A. cajannense (35 male, 30 female, 81 nymphs), A. neumanni (33 male, 41 female, 144 nymphs) and Amblyomma spp. (10 nymphs, 110 larvae). Most of the ticks were from the phytogeographical region of Chaco, one (B. microplus) was from an ecotone between the Chaco and the Andean Patagonia region, and the remainder of the ticks were from the Amazon region.

The geographic spread and temporal increase of the Lyme disease epidemic

OBJECTIVE

To describe the temporal and geographic progression of the Lyme disease epidemic in New York State from 1977 through 1989.

DESIGN

Communicable disease surveillance system.

SETTING

Statewide.

MAIN OUTCOME MEASURES

The progression of the epidemic was examined by analyzing trends in Lyme disease cases reported to the state surveillance system, town and county Lyme disease incidence rates, Lyme disease hospital discharge rates, and the distribution of Ixodes dammini ticks obtained from surveillance efforts and submitted for identification.

MAIN RESULTS

The number of confirmed Lyme disease cases in New York has increased with concurrent increases in the number of hospital discharges. The number of counties endemic for Lyme disease increased from four to eight between 1985 and 1989. The number of counties with documented I dammini ticks increased from four in 1985 to 22 in 1989. Incidence of the disease also increased within known endemic counties.

CONCLUSIONS

Tick surveillance indicated that the range of I dammini has expanded annually into areas up to 384 km from the original known endemic areas of Long Island, NY, and Connecticut. Cumulative data from human surveillance resources document both temporal increases and geographic expansion of the Lyme disease epidemic in New York.

Parasites of domestic and wild animals in South Africa. XXVII. Ticks on helmeted guineafowls in the eastern Cape Province and eastern Transvaal Lowveld

Seventy-six helmeted guineafowls (Numida meleagris) were shot in the Andries Vosloo Kudu Reserve and on an adjacent farm in the eastern Cape Province during the period May 1985 to January 1987 and their tick burdens determined. A total of 10 ixodid tick species were recovered, of which Amblyomma hebraeum, Amblyomma marmoreum and Haemaphysalis silacea were the most abundant. The seasonal abundances of these 3 species and of Hyalomma marginatum rufipes were ascertained. A marked difference between the total number of A. hebraeum recovered from the birds in the reserve and those on the farm is ascribed to the treatment of domestic stock on the farm with an acaricide. The tick burdens of 118 helmeted guineafowls, shot in the southern part of the Kruger National Park, eastern Transvaal Lowveld, from August 1988 to August 1990, were also determined. Ten ixodid tick species and the larvae of an argasid species were recovered. A. hebraeum, A. marmoreum and the Argas sp. were the most abundant and their seasonal abundances and that of Rhipicephalus zambeziensis were determined. Only 2 of the 54,659 ixodid ticks recovered from the birds at the 3 localities were adults and the presence of these is ascribed to accidental infestations.

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.

Efficacy of ivermectin delivered from an intraruminal sustained-release bolus against natural infestations of five African tick species on cattle

The efficacy of ivermectin delivered by an orally administered prototype sustained-release bolus over approximately 90 days was evaluated against natural infestations of five African tick species. Twenty cattle, allocated by restricted randomization based on counts of standard Boophilus decoloratus, were allocated to two groups and were either given an ivermectin bolus or designated as non-medicated controls. All cattle grazed a single pasture of native grasses for 20-40 days before treatment and until trial termination. Starting on Days 27, 40, 68 and 82 after bolus administration, four replicates were confined to individual tick-collection stanchions for 4 to 5-day periods. Ticks recovered from these cattle were counted by species, sex, and stage and degree of repletion; engorged females were weighed and incubated to determine the number which oviposited. For the other replicates, half-body counts of adult ticks (classified by species, sex and degree of repletion by females) were made at 1- and 2-week intervals through Day 90. Among replicates confined to stanchions periodically, fewer (P less than 0.05) engorged adult female B. decoloratus, Hyalomma spp., Rhipicephalus appendiculatus and Rhipicephalus evertsi evertsi were collected from bolus-treated cattle than from controls. Numbers of engorged adult female Amblyomma hebraeum were reduced, but differences were not statistically significant (P greater than 0.10). Among cattle maintained continuously on pasture, tick numbers were reduced on the ivermectin-treated groups. A significant (P less than 0.05) treatment by linear time effect was seen for all adult ticks counted except R. appendiculatus. A significant (P less than 0.05) treatment by quadratic time effect was seen for A. hebraeum, B. decoloratus and R. evertsi evertsi, and overall treatment differences were significantly different (P less than 0.05) for these species. The differences tended to increase with time. Except for Boophilus, reductions in tick numbers on treated animals relative to controls were not readily apparent. There were no adverse reactions attributable to ivermectin treatment or the presence of the bolus. Each treated animal retained its bolus throughout the trial, based on metal detection.

[Ornithodoros (Alectorobius) maritimus (Ixodoidea, Argasidae) a new species in Italy and observations on the coniceps-capensis group]

The soft tick of the coniceps-capensis group, Ornithodoros (Alectorobius) maritimus Vermeil & Marguet, 1967, is reported for the first time in Italy. Besides the systematic position and the distribution of the species, as well as observations on bird hosts, the biology and pathogenic role of the group species are discussed.

Borrelia burgdorferi in ticks of the Canton Tessin (Switzerland)

In the northern Alps it is hard to find an Ixodes ricinus population which does not harbour Borrelia burgdorferi. The infection rates range from 5 to 34% for adults and nymphs to 3.1% for larvae. This study shows that the infection rates on the southern side of the Alps are similar, at 25% for adults, 36.2% for nymphs and 3.2% for larvae. With respect to tick species other than I. ricinus, we did not succeed in finding any spirochetes in Dermacentor marginatus, Haemaphysalis punctata, Ixodes hexagonus, Rhipicephalus sanguineus.

Enzootic transmission of the agent of Lyme disease in rabbits

To determine whether cottontail rabbits (Sylvilagus floridanus) maintain an enzootic cycle of transmission of the Lyme disease spirochete (Borrelia burgdorferi), we examined the prevalence of infection in ticks and rabbits in a location in which rabbits were abundant. Of 72 unfed nymphal Ixodes dentatus swept from vegetation, 32% were infected by this spirochete, as determined by darkfield microscopy and indirect immunofluorescence using monoclonal antibody H5332. Infected ticks were reared from larvae feeding on each of 11 rabbits taken from the same site. Of 50 rabbits sampled there over a period of 2 years, sera of greater than 90% reacted with B. burgdorferi antigen by ELISA and by immunoblotting. Deer ticks (I. dammini) comprised less than 10% of ticks found on rabbits. We conclude that rabbits perpetuate the agent of Lyme disease in an enzootic cycle where rabbit-feeding Ixodes are abundant, that intensity of transmission is independent of the zoonotic cycle in mice, but that infection may occasionally be exchanged between these cycles.

Lyme disease. The hidden pandemic

Physicians will recognize Lyme disease faster if they maintain a high index of suspicion in a young patient with arthritis accompanied by negative rheumatoid factor and antinuclear antibody in combination with cardiac conduction problems or lymphocytic meningitis. The Lyme spirochete (Borrelia burgdorferi) has notable sensitivity to tetracycline, penicillin, and erythromycin; therefore, proper and complete treatment of the disease, once it is identified, can be easily achieved. Finkel observed that Lyme disease manifests itself as a "great imitator," as do many disorders caused by a spirochete. The total impact of Lyme disease on public health will be known only when the disease is fully recognized, consistently reported, and adequately managed.

[A human case of tick bite by Ixodes nipponensis on the scalp]

A human case of tick bite on the scalp was found at a local hospital on June, 1984. The patient, 63-year old female, was attacked by a tick while working in a farm forest which located in the suburbs of Seoul. The clinical complaint was a (worm) mass on the scalp which she thought as a tumor. On admission the patient complained of facial edema and general malaise. After removal of the mass (tick), small bleeding and discoloration were observed around the biting site. The tick was morphologically examined and identified as Ixodes nipponensis. This is the 4th human case of tick bite reported in the literature of Korea.

Potential for exposure to tick bites in recreational parks in a Lyme disease endemic area

Eight recreational parks located in a Lyme disease endemic area of southern New York State were surveyed for the presence of ticks during the summer of 1985 by drag sampling. Ixodes dammini, the primary vector of Lyme disease in the northeast, was found in all but one park and accounted for 580 (91.8 per cent) of the 632 ticks collected. Of these, 18 per cent were larvae, 80 per cent were nymphs, and 2 per cent were adults. An I. dammini encounter distance, defined as the mean number of meters traveled before encountering a nymphal or adult I. dammini on a drag cloth, ranged from 36 m in high-risk parks, to infinity (no tick encounters). Generally, areas of high use presented higher encounter distances (lower risk) than those of the entire park. Two of the three parks with the highest annual attendance also had the highest I. dammini population indices as projected from our sampling regimen. These results indicate that recreational parks in Lyme disease endemic areas represent a substantial human risk for tick bites and Lyme disease.

Ixodes dammini: occurrence and prevalence of infection with Borrelia spp. in Minnesota

The distribution of Ixodes dammini in Minnesota was studied by collecting adult ticks from hunting dogs during the grouse seasons in September and October of 1985 and 1986. The tick was most frequently found in the east-central part of the state. Borrelia spp. were observed by immunofluorescence in 10% of the ticks. The locations where ticks were found coincide with the primary endemic areas for Lyme disease in the state.

Efficacy of topically applied ivermectin against Boophilus microplus (Canestrini, 1887) in cattle

Systemic efficacy of ivermectin applied topically was evaluated against the cattle tick, Boophilus microplus. Twenty cattle with induced infestations were randomly allocated to five groups of equal size based on the numbers of engorged female ticks which fell through the slatted floor of individual pens during the 3 days prior to treatments. Control cattle were non-medicated. Cattle in three groups were given ivermectin at 200, 500 or 1000 mcg kg-1 in a topical formulation applied along the backline from the withers to the rump; cattle in the fifth group were given ivermectin in an injectable formulation subcutaneously at 200 mcg kg-1. Individual 24-h tick collections were made three times weekly for 5 weeks after treatment. Engorged female B. microplus were incubated to determine effects on reproduction. Based on the numbers of engorged female B. microplus collected following treatments, overall efficacy of ivermectin applied topically at 200, 500 and 1000 mcg kg-1 was 50, 85 and 91%, respectively, whereas ivermectin given at 200 mcg kg-1 subcutaneously was 80% effective. The index of reproduction for ivermectin given topically was reduced by 84, 94 and 95%, respectively, and that for ivermectin subcutaneously was 94%. No significant differences (P greater than 0.05) were found for these variables between ivermectin given topically at 500 or 1000 mcg kg-1 versus 200 mcg kg-1 given subcutaneously.

Ectoparasites of sympatric cottontails (Sylvilagus audubonii Nelson) and jack rabbits (Lepus californicus Mearns) from the high plains of eastern New Mexico

Eight species of ectoparasites were recovered from 35 Sylvilagus audubonii and 35 Lepus californicus occurring sympatrically near the Clovis-Portales area of eastern New Mexico. Recovered were Anoplura (Haemodipsus setoni), Diptera (Cuterebra lepusculi and Cuterebra ruficrus), Siphonaptera (Echidnophaga gallinacea and Euhoplopsyllus glacialis), and Acari (Ornithodoros parkeri, Dermacentor parumapertus, and Haemaphysalis leporispalustris). Jaccard's index showed a 50% ectoparasitic overlap with H. setoni, E. glacialis, D. parumapertus, and H. leporispalustris present on both host species. Cuterebra lepusculi, E. gallinacea, and Ornithodoros parkeri were taken only from S. audubonii, whereas C. ruficrus occurred only on jack rabbits. Euhoplopsyllus glacialis was the only species to demonstrate a preference for sex of host, occurring more abundantly on females.

Hepatozoon sp. in wild carnivores in Texas

Twelve coyotes (Canis latrans), three bobcats (Lynx rufus) and six ocelots (Felis pardalis) from the Gulf Coast of Texas were infected with Hepatozoon sp. The geographic distribution of infected wild animals coincides with the highest prevalence of Hepatozoon canis infection in domestic dogs for which the wild species may act as a reservoir.

Prevalence of piroplasmosis in equines in the Colombian province of Cordoba

Eighty-two equine sera from 13 farms in northern Colombia were examined for antibodies to Babesia caballi and B. equi using the complement fixation (CF) and the indirect fluorescent antibody (IFA) test. Seroreactors to both piroplasms were present on all farms. The IFA test indicated a prevalence of 90% for B. caballi and 94% for B. equi. The CF test detected antibodies to B. caballi in 41% and to B. equi in 65% of the animals. The prevalence of seroreactors in different age groups revealed a significant decline in CF antibodies to B. caballi in animals older than three years. IFA titres for both Babesia spp. gradually declined with increasing age of the animals but were still present in most animals of the oldest age group (over nine years old). Anocentor nitens was found on all farms whereas Amblyomma cajennese was found only on two farms located on the coast.

Prevalence of Ixodes dammini near the homes of Lyme disease patients in Westchester County, New York

Cases of Lyme disease that occurred in Westchester County, an affluent suburb north of New York City, in 1983 were investigated in 1983 and 1984 to determine the presence of Ixodes dammini (Acari: Ixodidae) in the vicinity of the patients' homes. Small mammal trapping, drag cloth, and carbon dioxide-baited tick traps were used to sample ticks. In all but one of 11 cases investigated, I. dammini was found on or near well-maintained lawns in the immediate vicinity of the residences. A mark-release-recapture experiment to determine tick abundance in one 700 m2 lawn resulted in an estimate of 6800 adult ticks (approximately 1 per m2). Dark-field microscopic examination of tick midgut tissues revealed that 33% of nymphs and 55% of adult ticks from this lawn contained spirochetes. These data suggest that many cases of Lyme disease in Westchester County, New York, may be acquired at home as a result of activities on the lawn.

Seed ticks

Seed ticks, the first-stage larvae of hard ticks, are not always recognized. They are tiny (0.6 mm) and have six legs, rather than the eight legs found on nymphal and adult ticks. Seed ticks may transmit Rocky Mountain spotted fever, tularemia, babesiosis and Lyme disease. Pediculocides are effective in removing the larvae.

Prevalence of Borrelia burgdorferi and Babesia microti in mice on islands inhabited by white-tailed deer

Borrelia burgdorferi and Babesia microti were isolated from 35 of 51 white-footed mice (Peromyscus leucopus) and meadow voles (Microtus pennsylvanicus) captured on two Narragansett Bay, R.I., islands inhabited by deer, the principal host for the adult stages of the vector tick, Ixodes dammini. Immature ticks parasitized mice from both islands. From 105 mice captured on four other islands not inhabited by deer neither pathogen was isolated, nor were I. dammini found.

[Studies on ticks (Acarina, Ixodidae), parasites of cattle in West Algeria. I. Systematic survey and seasonal activity]

Tick samples (Acarina, Ixodidae) were collected for two years on bovidae from the whole Oran area which were brought weekly at the Oran open market (Algeria). The 5,500 ticks thus obtained could be divided into six genera and twelve species. From the phenological analysis the following were defined: three spring species (Rhipicephalus bursa, Rh. turanicus and Rh. sanguineus), three summer species (Hyalomma detritum, H. impeltatum and Boophilus annulatus), three winter species (Ixodes ricinus, Haemaphysalis punctata and Dermacentor marginatus) and three species called perennial (H. marginatum, H. excavatum and H. lusitanicum). In fact, the latter are present on cattle all year around, but in winter, the collected specimens (mostly male and a few females) remain fixed on their host without feeding. The parasitic intensity for each species and its relative distribution pattern were studied monthly on cattle from november 1981 to september 1983. The distribution on host of different species was analyzed. Short rostrum ticks were found to have a significant preference for specific habitats (depending on the thickness of the teguments) while long rostrum species are fixed on more varied sites. In the case of plurispecific infestations of the same area, phenomena of competition-exclusion were not observed. Most of the animals are simultaneously infected by two or four different species of ticks. Taking into account this first estimation, it was possible to define two types of associations both related to the rearing methods and geographical source of bovines.(ABSTRACT TRUNCATED AT 250 WORDS)

[Characteristics of the distribution of Ixodes persulcatus in the forest-park area of Novosibirsk]

Only one species of ixodid ticks Ixodes persulcatus occurs in the forest-park zone. Conditions of foliage forests with high grass, where occur hosts of all developmental phases of ticks (elks, hares, rodents, insectivores), are most favourable for I. persulcatus. Preimaginal phases of I. persulcatus feed, in general, on dominant species (common shrew, redbacked and narrow-skulled voles, field mouse and northern birch mouse).

The subgenus Persicargas (Ixodoidea: Argasidae: Argas): A. (P.) arboreus central nervous system anatomy and histology

The anatomy and histology of the adult Argas (Persicargas) arboreus central nervous system are described and compared with these properties in other ticks. The single, integrated, central nerve mass (CNM) is formed by a fused supra-esophageal part (protocerebrum, cheliceral ganglia, palpal ganglia, and stomodeal pons) and a subesophageal part (4 pairs of pedal ganglia and the complex opisthosomatic ganglion). Single peripheral nerves (pharyngeal and recurrent) and paired peripheral nerves (compound protocerebral, cheliceral, palpal, pedal and opisthosomatic) extend from the CNM to body organs and appendages. Optic nerves, described in other Argas species, are not found in A. (P.) arboreus. Histologically, the CNM is enclosed by a thin-walled periganglionic blood sinus and invested by a collagenous neural lamella followed by a perineurial layer composed of glial cells and containing fine reticular spaces, a cortical layer of association, motor and neurosecretory cell bodies and glial cells, and inner neuropile regions of fiber tracts forming 5 horizontal levels of connectives and commissures.

Erythema chronicum migrans of Lyme disease

Erythema chronicum migrans (ECM) is the distinctive cutaneous lesion of the multisystem tick-borne spirochetosis, Lyme disease. Its clinical and histologic pictures are variable. Of the 51 patients with ECM of Lyme disease, 38 patients (75%) had single lesions, 13 patients (25%) had multiple lesions, and 32 patients (62%) had extracutaneous signs and symptoms. Only 15 patients (29%) had symptoms referable to ECM. Extracutaneous signs and symptoms were absent in 12 (80%) of the 15 patients. These patients had uneventful recoveries following treatment with systemic antibiotics. Thirty-four skin biopsy specimens were obtained from the ECM lesions of 30 patients. With Warthin-Starry silver stain, the Ixodes dammini spirochete was found in 14 specimens (41%) taken from 12 (40%) of the 30 patients. Two of the Ixodes dammini spirochete-positive specimens were obtained from secondary ECM lesions. Careful clinical and histologic examination of skin lesions suggestive of ECM of Lyme disease will expedite its early diagnosis and treatment.

The ixodid tick burdens of various large ruminant species in South African nature reserves

The ixodid tick burdens of eland (Taurotragus oryx), greater kudu (Tragelaphus strepsiceros), nyala (Tragelaphus angasi), bushbuck (Tragelaphus scriptus) and giraffe (Giraffa camelopardalis) in the Kruger National Park, Transvaal; of African buffalo (Syncerus caffer) and nyala in the Hluhluwe Game Reserve, Natal; and of gemsbok (Oryx gazella) in the Mountain Zebra National Park, an eland in the Thomas Baines Nature Reserve and an eland and greater kudu in the Andries Vosloo Kudu Reserve, eastern Cape Province, were determined. The tick burdens of animals shot at the same time and locality are compared, and the attachment sites of some tick species on some of the hosts are given.

Some ecological observations on two east-Mediterranean species of Haemaphysalis ticks parasitizing domestic stock

Haemaphysalis cretica and H. otophila thrive in the Mediterranean phytogeographic zone of the eastern Mediterranean area. Haemaphysalis otophila has a wide geographical distribution, H. cretica is more restricted. The adults of both species parasitize sheep and goats, and transmit diseases. The pre-imaginal stages feed on reptiles and small mammals. Adults attach to their hosts only during winter. The pre-oviposition period is long and the embryonic development is slow. Larvae hatch in spring and attach to their hosts in early summer; nymphs follow somewhat later and descend off their hosts in late summer. There is only one generation per year for each of the species.

Relationship between ticks and Zebu cattle in southern Uganda

Tick populations were observed on zebu (Bos indicus) cattle over a period of 2 years at Entebbe, Uganda where the climate was thought to be highly favourable for the free-living stages of ticks. collections of all instars of ticks were made from the body surfaces of the cattle at intervals of between 1 and 5 weeks. The species recorded in order of decreasing abundance were Rhipicephalus appendiculatus, Amblyomma variegatum, Boophilus decoloratus, Rhipicephalus evertsi evertsi, Rhipicephalus simus, Rhipicephalus compositus and Hyalomma marginatum rufipes. The rankings of the cattle based on burdens of any particular species of tick were always correlated with their rankings for other species; animals that carried more adult stages of a species also carried more of its immature stages. There were more adult males than females of R. appendiculatus, A. variegatum and R. e. evertsi even when the cattle had had all ticks removed 1 week previously; several possible mechanisms are suggested to explain the biased sex ratio. It is concluded that there is promise for improvement in control of 3-host ticks by increasing the resistance of herds of zebu cattle by culling or selective breeding.

Isolation and characterization of Midway virus: a new tick-borne virus related to Nyamanini

Midway virus, a new tick-borne virus isolated from two species of Ornithodoros (Alectorobius) ticks of the capensis group (O capensis, O denmarki), is described from Midway, Kure, and Manana islands in the Central Pacific (Hawaiian Archipelago) and from northern Honshu (Japan). Midway virion is enveloped, unusually large, acid and temperature sensitive, and its type of nucleic acid is RNA. Complement-fixation (CF) tests show a close relation of Midway to Nyamanini virus, which has been isolated from ardeid birds and Argas ticks in Africa, the Indian subcontinent, and Southeastern Asia. However, cross-box tests (CF, mouse and tissue culture neutralization, immunofluorescence) show that these two viruses are quite distinct. Midway virus is lethal for newborn Swiss mice inoculated by intracerebral, but not intraperitoneal route. It fails to kill four-week-old mice by either route. Midway virus causes cytopathic effects in BHK-21 cells and titerable plaques in Vero cells. Antibodies to it were prevalent among nestlings of Larus crassirostris (Black-tailed Gull) on Aomatsushima I., but were scarce among those of Nycticorax nycticorax (Black-crowned Night Heron) of the same island.

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.