Haemaphysalis Leporispalustris Research Articles

Seasonal Activity and Frequency Distributions of Ticks (Acari: Ixodidae) Infesting Snowshoe Hares in Nova Scotia, Canada

Seasonal activity and infestation patterns of the rabbit tick, Haemaphysalis leporispalustris ; and the American dog tick, Dermacentor variabilis , on Snowshoe Hare, Lepus americanus , populations were studied in a 12-ha area of southwestern Nova Scotia during the summers of 1974 to 1976. All feeding stages of the rabbit tick, but only larvae and nymphs of the American dog tick, were collected from hares. Seasoual peak activities for each feeding tick stage indicated that the majority of individuals of both tick species undergo a 2-year life cycle in Nova Scotia. Although both tick species exhibited a markedly clumped distribution on the hares, which could be described by a negative binomial distribution, the distribution patterns were different for each species. Over ¾ of all hares trapped each summer were infested with each of the stages of H. leporispalustris , whereas less than ½ were infested with either the larvae or nymphs of D. variabilis . Differences in host species requirements by the ticks may explain the differences in the distribution patterns.

Development, Survival, and Oviposition of the Rabbit Tick, Haemaphysalis leporispalustris (Packard) (Acari: Ixodidae), at Constant Temperatures

The relationship between development, survival, and oviposition rates, and five constant temperatures is described for the developing and reproductive life stages of the rabbit tick, Haemaphysalis leporispalustris (Packard). Development was most rapid at 29.7 C for egg and larvae, and 35.6 C for nymphs. Survival was greatest between 14.7 and 29.7 C, but was reduced at 35.6 C for eggs and larvae. Oviposition was optimal between 19.9 and 29.7 C with a maximum mean daily oviposition of 253 eggs/female/day on the third day of oviposition at 29.7 C. Maximum mean total eggs per female produced was 1,157 with a range of 277 to 3,327. The total number of eggs produced per female correlated with the weight of the engorged female. Both linear and sigmoid curve equations were used to approximate the relationship between the temperature and development rates of eggs, larvae, and nymphs. The nymphs had the highest heat requirements of the 3 development stages. Comparisons with field host-parasite data indicate that the rabbit tick has a 2-yr life cycle in southwestern Nova Scotia.

Field Study of the Relationship between Skin-Sensitizing Antibody Production in the Cottontail Rabbit, Sylvilagus floridanus, and Infestation by the Rabbit Tick, Haemaphysalis leporispalustris (Acari: Ixodidae)

The resistance of cottontail rabbits to tick feeding appears correlated with the rabbits' development of skin-sensitizing antibodies. Resistance appeared to be greatest in adult rabbits which had been repeatedly infested with ticks. Rabbits with little exposure to ticks, usually the young cottontails, showed little or no skin-sensitizing antibody present in their blood and usually had relatively high tick loads when compared with adult rabbits. Models used to interpret the data show promise as tools for predicting tick population fluctuations and, perhaps, incidence of vector borne disease outbreaks. The existence of resistance to tick attachment has important implications for the host-parasite relationship. The research lends support to the hypothesis that the resistance may function as a homeostatic regulatory mechanism capable of maintaining the size of the tick population in equilibrium with the size of the rabbit population. In this way, host resistance may be advantageous to the parasite as well as to the host.

Ixodiphagus texanus Howard (Hymenoptera: Encyrtidae) a parasite of the rabbit tick in Nova Scotia

An encyrtid wasp, Ixodiphagus texanus, was found parasitizing larvae and nymphs of the rabbit tick, Haemaphysalis leporispalustris, that had engorged on snowshoe hares, Lepus americanus, in a study area in southwestern Nova Scotia. Laboratory experiments on the development of the wasp and observations on the seasonal occurrence on wild-caught hosts indicated the wasp has at least two generations per year.

Ectoparasites of the Ringtail, Bassariscus Astutus, from West Texas

One louse, 6 flea, 8 mite and 4 tick species were recovered from 14 Ringtails, Bassariscus astutus , collected from several localities in Central and West Texas. Hosts were infested with from 1 to 7 species of ectoparasites. Malaraeus sinomus, Anomiopsyllus nudatus, Orchopeas sexdentatus subspecies #1 and #2, Polygenis gwyni, Euschoengastia eadsi, Pseudoschoengastia apista, Eucheyletia hardyi, Cheyletus eruditus, Dermacarus hypudaei, Hirstionyssus breviseta, H. staffordi, Androlaelaps fahrenholzi, Dermacentor variabilis, Ixodes conepati , and Haemaphysalis leporispalustris are new host records for the Ringtail. Only the louse Neotrichodectes thoracicus appears to be host-specific.

Climbing Behavior and Host-Finding of Larval Rabbit Ticks (Haemaphysalis leporispalustris)

The rabbit tick (Haemaphysalis leporispalustris) is highly host-specific. Adults feed almost exclusively on rabbits. Immatures feed primarily on rabbits but will attack birds. When larvae leave the daytime resting form of the rabbit, they climb up to a position on vegetation where they can encounter a host. Experiments using glass rod models to represent vegetation showed that ticks selected a position which had greatest substrate curvature and was at rabbit body height. This strato-orientation restricts the tick's host spectrum to rabbits and ground-dwelling or feeding birds.

New Minto virus: a new rhabdovirus from ticks in Alaska.

Three strains of a virus were isolated from Haemaphysalis leporis-palustris (Packard) ticks removed from snowshoe hares (Lepus americanus Erxleben) in east central Alaska. We suggest that the virus be named New Minto for the location in which the ticks were collected. Prototype New Minto virus is sensitive to the action of sodium deoxycholate and kills suckling mice by the intracerebral but not intraperitoneal route; weaned mice do not die after intracerebral, intraperitoneal, or subcutaneous inoculation. The virus produces plaque in serially propagated Vero but not in primary Pekin duck embryo cells. By complement-fixation and neutralization tests New Minto is related to Sawgrass Virus, a hitherto ungrouped virus from Florida. The establishment of a Sawgrass group is suggested. In addition, Sawgrass virus was found by electron microscopy to belong to the Family Rhabdoviridae.

Suckling mouse cataract agent is a helical wall-free prokaryote (spiroplasma) pathogenic for vertebrates.

THE suckling mouse cataract agent (SMCA) is a filterable organism originally isolated from a pooled extract of rabbit ticks (Haemaphysalis leporis-palustris) collected near Atlanta, Georgia in April 1961 (ref. 1). The agent grows to high titre in the eyes and brains when inoculated intracerebrally into newborn mice in which it induces cataract, uveitis and chronic brain infection1–3. SMCA has also been grown to high titre in embryonated hen's eggs, in which it produces a lethal infection in 4–9 d (ref. 1). The agent has not been grown in tissue culture or in artificial media, but growth in a rabbit lens organ culture has been reported4. Stained SMCA-infected tissues failed to show the presence of rickettsiae and, as a result of such negative inferences and other characteristics of the agent3–5, it was considered to be a candidate slow virus6. Within the past few years however, ultrastructural and biological studies showed that a wall-free prokaryote was consistently associated with the acute and chronic disease in mice and with lethality in chick embryos7,8. Although the agent resembled mycoplasmas morphologically, it differed from them in its apparent non-cultivability on conventional mycoplasma medium. We now report that the organism associated with the suckling mouse cataract syndrome is a prokaryote similar to the spiroplasmas—a group of mycoplasmas known previously only from plants and insects.

Notes on the role of ticks feeding on lagomorphs and ingestion of ticks by vertebrates in the epidemiology of Rocky Mountain spotted fever.

Sonenshine & Clifford (1973, J. Med. Ent. 10 : 497–502) reported on the incidence of rickettsiae of Rocky Mountain Spotted Fever (RMSF) in birds in Virginia, and on the extent of infestation of these birds with immature Haemaphysalis leporispalustris (Packard). McKiel (unpubl.) obtained similar data for SW Nova Scotia, and Martell, Yescott & Dodds (1969, Can. J. Zool. 47 : 183–84) reported on some infestations of birds in Nova Scotia. All stages of H. leporispalustris occur abundantly on lagomorphs (e.g., Sylvilagus and Lepus ) in North America, but there continue to be questions about links between the bird- Haemaphysalis -Iagomorph cycle and the rodent- Dermacentor -larger mammal (including man) cycle of RMSF. Sonenshine & Clifford (1973, loc. cit.) found very few Dermacentor variabilis (Say) on Sylvilagus in Virginia, and they stated “the data do appear to raise doubts as to its (i.e., involvement of ticks on birds in spreading RMSF to ticks that infect man) importance and suggest the need for further study and evaluation.” This note (1) presents new data on the infestation of hares with both Dermacentor and H. leporispalustris in Nova Scotia and (2) draws attention to the plausibility of another link between the cycles, that of ingestion of ticks by vertebrates.

Laboratory rearing procedures and equipment for multi-host ticks (Acarina: Ixodidae).

Sacktor et al. (1948, J. Econ. Ent. 41 : 296–301), Lancaster (1955, J. Econ. Ent. 48 : 295–97), and Loomis (1961, J. Parasitol. 47 : 91–99) reported on laboratory rearing methods for ixodid ticks. These methods are apparently without the capacity for producing large numbers of ticks economically. The following procedures are currently used at our laboratory to rear large numbers of uniformly aged ticks of the following species: Amblyomma americanum (L.), A. maculatum Koch, A. cajennense (Fabricius), Dermacentor variabilis (Say), D. parumapertus (Neuman), HaemaPhysalis leporispalustris (Packard), and Rhipicephalus sanguineus (Latreille). We assume that these techniques are applicable to numerous other multi-host species.

Arthropod Parasites of the Collared Peccary, Tayassu tajacu (Artiodactyla: Tayassuidae), from New Mexico

Collared peccaries, Tayassu tajacu, collected in Hidalgo County, New Mexico, in 1964 and 1973 were found to be irregular hosts the sucking louse, Pecaroecus javalii Babcock and Ewing (Haematopinidae), the spinose ear tick, Otobius megnini (Dug'es) (Argasidae), and a psoroptid ear mite, heretofore unrecorded from North America, thought to be Trouessalges pecari da Fonseca (Psoroptidae). Also collected were the winter tick, Dermacentor albipictus (Packard) (Ixodidae), from a peccary, and 0. megnini from a bobcat skin, Lynx rufus (Felidae). A summary previously unpublished tick (Ixodoidea) collections from the peccary, deposited at the Rocky Mountain Laboratory, Hamilton, Montana, is included. Babcock and Ewing (1938) described a new genus and species sucking louse, Pecaroecus javalii Babcock and Ewing (Haematopinidae), from a collared peccary, Tayassu tajacu (as Pecari angulatus), collected about 12 miles west Juno, Val Verdi County, Texas, on 29 January 1932. They also mentioned that mites of a species Sarcoptidae were found within many the attached empty egg shells this new louse, but that no mites were found on the skin the host. Menzies et al. (1951) reported the same giant sucking louse (as P. javalli [sic]) from peccaries (as Tayassu angulatum) west the Pecos River, in Terrell County, Texas; Eads (1951) published a note on the occurrence P. javalli [sic] on one 20 peccaries, examined over a 5-year period, which had been shot in Aransas, Kleberg, Nueces, Terrell, and Uvalde counties, Texas, and reported the presence the peccary flea, Pulex porcinus Jordan and Rothschild, on all them. He also reported finding the ixodid ticks, Amblyomma americanum (L.), A. cajennense (F.), A. maculatum Koch, Dermacentor variabilis (Say), and Ixodes scapularis Say, but did not identify which ticks came from which counties. Neal (1959) reported external parasites from 85 peccaries in Arizona, as follows: Pecaroecus javellii [sic] on 7; the human flea, Pulex irritans L., and the tropical hen flea, Echidnophaga gallinacea (Westwood) on 3; Ornithodoros turicata (Dug'es) (Argasidae) on 1; and Dermacentor albipictus (Pack.) on 1. Rapp and Jones (1962) recorded Percaroecus [sic] javalii from the same species tayassuid Received for publication 28 January 1975. (as Pecarii tojacu [sic] sonoriensis) from Pima County, Arizona. McDaniel et al. (1966) recorded collections the giant sucking louse from the type locality, and Samson and Donaldson (1968) recovered 3 and 13 lice (P. javalii) from around the eyes 2 30 peccaries (as Tayassu tajacu sonoriensis) in southwestern New Mexico. Cooley (1938) republished the record for Dermacentor halli McIntosh, 1932 (Ixodidae) from peccaries in southern Texas. Samuel and Low (1970) collected giant sucking lice from the peccary (as Dicotyles tajacu angulatus) from locations in Crockett and Brewster counties in western Texas and the ixodid ticks, Amblyomma cajennense, A. inornatum Banks, Dermacentor variabilis, and Haemaphysalis-leporis palustris (Packard), from the same host species from locations in Kleberg and San Patricio counties in southern Texas. They also recorded the peccary flea, Pulex porcinus, from all four locations. Previously unpublished records Ixodoidea, now residing in the collection the Rocky Mountain Laboratory, from peccaries, have been made available to me (Table I). These include 1 female Ornithodoros turicata from Pima County, Arizona; 4 collections Amblyomma cajennense from Live Oak, Willacy, and Kenedy counties, Texas; 1 collection A. imitator Kohls from somewhere in Mexico; 1 collection Boophilus annulatus (Say) from the King Ranch in Texas; 1 collection Dermacentor halli from somewhere in Mexico and 1 from the King Ranch; and 3 collections D. variabilis from Willacy and Dimmit counties, Texas (Fig. 1).

Parasites of the black-tailed jackrabbit in north central Colorado.

Forty-four black-tailed jackrabbits, Lepus californicus melanotis Mearns, 1890, were collected near Denver from August, 1972, through July, 1973, and amined for parasites. Recovered parasites and their infection rates were: Eimeria sp. 100%, Cittotaenia sp.27%, coenuri of Multiceps sp. 57%, Cediopsylla inaequalis 14%, Hoplopsyllus affinis 9%, Haemodipsus setoni 2%, Dermacentor andersoni 14%, and Haemaphysalis leporis-palustris 25%.

Concentration of the Ingested Meal in Four Species of Hard Ticks 1

The concentration of the bloodmeal in the larvae, nymphs, and adult females of the Cayenne tick, Amblyomma cajennense (F.), Gulf Coast tick, Amblyomma maculatum (Koch), American dog tick, Dermacentor variabilis (Say), and rabbit tick, Haemaphysalis leporispalustris (Packard), allowed to feed to repletion on laboratory hosts was determined. The lowest concentration (average: 1.59 times) occurred in the larvae, due to a relatively large proportion of non-blood tissue ingested with the blood. Nymphs showed a much higher concentration (average: 2.39 times), and adult females the highest (average: 2.78 times). Many significant differences were found among the species of ticks.

On the natural occurrence of California encephalitis virus and other arboviruses in Alaska

California encephalitis virus (Snowshoe Hare strain) was isolated from these Alaskan sources: varying hare (snowshoe hare), Lepus americanus Erxleben; indicator rabbit, Oryctolagus cuniculus (Linnaeus); varying lemming, Dicrostonyx rubricatus (Richardson); northern red-backed vole, Clethrionomys rutilus (Pallas); mosquitoes, Aëdes spp.; and blackflies, Simulium sp. This virus has been confirmed as enzootic in east-central Alaska. Other arbovirus isolations were Silverwater virus, from hare-ticks, Haemaphysalis leporispalustris (Packard); Great Island virus and a virus of the Sakhalin group from bird ticks, Ixodes signatus Birula, from common murres, Uria aalge (Pontoppidan); and Northway virus, a hitherto undescribed member of the Bunyamwera group from a northern red-backed vole, from indicator rabbits, and from hematophagous Diptera. These findings include new host-records and extensions of the known geographic range of some of the viruses isolated.

Critical temperature and changes in cuticular lipids in the rabbit tick, Haemaphysalis leporispalustris

The epicuticle in the rabbit tick, Haemaphysalis leporispalustris, appeared to be continuously changing, with deposition and removal of lipids during and after engorgement. These changes were accompanied by corresponding changes in critical temperature. The correlation between changes in critical temperature and composition of cuticular lipids (i.e. changes in the number, types, and relative concentration of lipid classes) suggested that changes in lipid composition could be responsible for changes in critical temperature. A hypothesis, alternative to those of Beament and Locke, is proposed to explain the phenomenon of critical temperature. At critical temperature, certain lipids probably change phase from crystal to liquid crystal, with hydrocarbon chains in a highly mobile condition. The hypothesis is not based on the presence of a water-proofing monolayer, and is supported by transition phenomena known in many lipids.

Changes in Critical Temperature During Nymphal and Adult Development in the Rabbit Tick, Haemaphysalis Leporispalustris (Acari: Ixodides: Ixodidae)

ABSTRACT During the developmental period from nymphal to adult engorgement of the rabbit tick, Haemaphysalis leporispalustris, critical temperature changed with developmental stage and nutritional state, but was similar in the two sexes. Critical temperature was low in engorged nymphs one day after drop-off (in the range of 36–40 °C), increased during the following 15 days (46–47 °C), slightly decreased just after ecdysis (42–43 °C), remained constant in unfed females for the next 2 months (42–43 °C) and then decreased again during engorgement of adult females (from 42–43 to 37–38 °C then to 35–36 °C). The rates of water loss also changed with the developmental period. The hypothesis that evaporative water loss might initiate the rapid engorgement phase is supported, although not confirmed, by a close correspondence between the host body temperature and the critical temperature of the tick just prior to the rapid engorgement phase.

Arthropod parasites collected from white-tailed deer.

5864 white-tailed deer (Odocoileus virginianus) from the United States, the U.S. Virgin Islands and Cuba were examined for ectoparasites. Most of the collections were made in the southeastern United States. Twenty-five species of arthropods were found which included Metastigmata: Amblyomma americanum, A. maculatum, Boophilus annulatus, B. microplus, Dermacentor albipictus, D. nigrolineatus, D. nitens, D. variabilis, Haemaphysalis leporispalustris, Ixodes affinis, I. scapularis, Rhipicephalus sanguineus; Prostigmata; Eutrombicula sp., Neotrombicula whartoni; Astigmata: Demodex sp., Psoroptes sp.; Mesostigmata: Raillietia auris; Anoplura: Haematopinus suis, Solenopotes binipilosus; Mallophaga: Tricholipeurus lipeuroides, T. parallelus; Diptera: Cephenemyia Phobifera, Lipoptena cervi, L mazamae; Siphonaptera: Cediopsylla simplex.

Drop-off rhythms of engorged rabbit ticks, Haemaphysalis Leporispalustris (Packard, 1896) (Acari: Ixodidae).

A definite rhythm of dropping off the host following engorgement is a part of the behavior of each of the 3 instars of the rabbit tick, HaemaPhysalis leporispalustris. Experiments done in the laboratory under controlled conditions revealed that as much as 90% of the total “drop-off” of larvae, nymphs, and adults occurred during the daytime in a 6-hr interval that ended 2 hr before the onset of darkness. The periodicity of drop-off is regulated primarily by a circadian rhythm of the ticks which is entrained by the daily light cycle. It appears that darkness plays the principal role in setting the phase of the rhythm. Experiments in which drop-off occurred in either constant light or darkness yielded evidence that the drop-off of ticks which had not been entrained by a light cycle could be influenced by some physiological rhythm of the lagomorph host.

Mass Rearing of Radioisotope-Tagged Larval Ticks for Ecological Investigations12

The results of 3 years of experience with mass rearing Radio labeled larval ticks for use in field studies are reported. Mass rearing was done with the American dog tick, Dermacentor variabilis (Say); the lone star tick, Amblyomma americanum (L.); and the Rocky Mountain wood tick, D. andersoni Stiles; small numbers of tagged larvae of the rabbit tick, Haemaphysalis leporispalustris (Packard), also were reared. Inoculation of 14C glucose into engorged, procreant females of these 4 species was done to provide sufficient suitably tagged larvae to meet the needs of field programs, ranging from only a few thousand in 1 species to approximately 250,000 per year in another species. Evaluation of the mass rearing program revealed that yields of suitably tagged larvae were substantially less than predicted in previous published studies. Responsibility for the reduced yield was attributed, primarily, to decreases in transtadial transmission efficiency (eggs to larvae) and percent hatching, both of which were less than expected. Nevertheless, the planned overproduction of tagged larvae compensated for these reductions in yield (except in 1 instance). The program was found to be practical both in yield and economics.

Ultrastructural changes in the nymphal salivary glands of the rabbit tick, Haemaphysalis leporispalustris, during feeding

Changes occurring in the salivary glands of the rabbit tick, Haemaphysalis leporispalustris, during feeding have been investigated by light and electron microscopy. Anatomically, the salivary glands consist of two glandular masses, lying in the lateral regions of the body cavity, which are composed of numerous alveoli of two distinct types: (1) non-granule-containing, and (2) granule-containing alveoli, referred to as type I and II alveoli respectively. Type I alveoli lack granules and appear to contribute very little to the salivary secretion, whereas type II alveoli contain two granule types in unfed ticks and three types in actively feeding ticks. Histochemical staining was used in the tentative determination of the chemical composition of some of the granules present in the type II alveoli and possible functions of these granules are considered in relation to feeding mechanisms in ixodid ticks. Also discussed is the possible functional significance of type I alveoli in water transport and ionic regulation as these relate to concentration of the blood meal.