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PubMed2000

Density and spatial distribution of Ixodes pacificus (Acari: Ixodidae) in two recreational areas in north coastal California.

The density and distribution of Ixodes pacificus was assessed at 2 parks in north coastal California. The density of I. pacificus adults and nymphs varied significantly between years, trails, and sides of trails. Adult ticks occurred on vegetation along sun-exposed trails in January through March, their density (0-1.93 per 20 m) correlated with brush density, trail width, and presence of an uphill slope. Nymphs (0.06-5.10 per 20 m) occurred in leaf litter along shaded trails in May-July. Adult I. pacificus were rare at picnic sites (0.00-0.24 per 20 m), but nymphal densities (0.93-2.37 per 20 m) were comparable with those along some shaded trails. The prevalence of Borrelia burgdorferi in ticks (2.8% overall) did not differ significantly between locations, years, or stages. We conclude that the risk of acquiring Lyme disease in these sites is low, but varies among trails, seasons, and years.

Animals↗
PubMed1976

Ixodes scapularis Say on white-tailed deer (Odocoileus virginianus) from Long Point, Ontario.

Ixodes scapularis Say was the only species of tick found on white-tailed deer, Odocoileus virginianus, collected at Long Point, Ontario from October 1972 to August 1973. Adults were most abundant from September 1972 to April 1973. Larvae were found throughout the study period except during February. Nymphs were scarce during winter months but fairly common during spring and summer. Most adults were found on the neck and shoulders. Larvae occurred mainly on lower regions of the body and nymphs mainly on the head, shoulders, forelegs and brisket.

Animals↗
PubMed1993

The groundhog tick Ixodes cookei (Acari: ixodidae): a poor potential vector of Lyme borreliosis.

Evidence for infection with the spirochete, Borrelia burgdorferi, was sought in Ixodes cookei and in groundhogs (Marmota monax) in southern Ontario, Canada, and ticks fed on experimentally inoculated hosts were examined for the spirochete. Borrelia burgdorferi was not detected by immunofluorescent examination of 110 larval, nymphal or adult I. cookei collected from the environment, or taken from humans and other animals. Three groundhogs inoculated with B. burgdorferi developed titers of 1:20 to 1:80 by the indirect immunofluorescent antibody test, but B. burgdorferi was not isolated from the spleens, kidneys, or urinary bladders of these animals. One of 30 wild groundhogs had an antibody titer of 1:20 to B. burgdorferi. Three (5%) of 59 I. cookei larvae fed on B. burgdorferi-infected hamsters became infected, in comparison with 23 (28%) of 82 I. dammini larvae fed on the same hosts. Borrelia burgdorferi was present in 5%, 16% and 4% of molted I. cookei nymphs fed on infected hamsters, rats or a groundhog, respectively; prevalences of infection in I. dammini fed on the same hosts were significantly (P < 0.05) higher (45%, 36%, and 23%, respectively), as was the intensity of infection. A naive groundhog on which I. cookei nymphs from an infected cohort fed did not become infected with B. burgdorferi, but it is uncertain whether an infected tick engorged on the experimental host. Ixodes cookei seems to be an inefficient vector of B. burgdorferi, and is unlikely to be significant in nature. Groundhogs are potential wildlife reservoirs of B. burgdorferi, based on their capacity to transmit infection to I. dammini.

Animals↗
PubMed1997

Role of the eastern chipmunk (Tamias striatus) in the epizootiology of Lyme borreliosis in northwestern Illinois, USA.

The role of the eastern chipmunk (Tamias striatus) in the epizootiology of Lyme borreliosis was evaluated in Castle Rock State Park, Illinois (USA), an enzootic region, from June to August 1993. Prevalence, intensity, and molting rate of immature Ixodes scapularis were determined for chipmunks, white footed mice (Peromyscus leucopus), and raccoons (Procyon lotor). Chipmunks were the primary host for I. scapularis nymphs and an important secondary host for I. scapularis larvae. Based upon ear punch biopsy analysis, B. burgdorferi prevalence in chipmunks was similar to that of mice in August and greater than that of mice in June and July. Thus we propose that chipmunks are the primary source of B. burgdorferi infection for I. scapularis nymphs and an important secondary source of infection for larvae.

Animals↗
PubMed1976

Observations on the development of Rhabdochona phoxini Moravec, 1968 (Nematoda: Rhabdochonidae).

The life-cycle of the nematode Rhabdochona phoxini, an intestinal parasite of the fish Phoxinus phoxinus, has been studied experimentally. The mayfly nymphs, Habrophlebia lauta Eaton and H. fusca (Curtis) were found to serve as experimental intermediate hosts. After the eggs of R. phoxini have been swallowed by the mayfly nymph, the toothed first-stage larvae of this parasite are released and penetrate through the intestinal wall into t-e body cavity of the mayfly. Before reaching the infective third stage, the larvae moult twice in the body of the invertebrate host (2 to 16 and20 to 36 days after infection at water temperatures of 13--15 degrees C). However, the development of the encysted infective larvae does not cease in the intermediate host and the larvae may undergo one more moult. One of two moults then occur in the intestine of the definitive host (Phoxinus phoxinus) (depending on the fact whether it was infected with third- or fourth-stage larvae) before the larvae attain the maturity. The development of R. phoxini in the definitive host lasts about two months.

Animals↗
PubMedDate not supplied

[Transovarial and transphasic transmissions of Borrelia by the taiga tick Ixodes persulcatus (Ixodidae)].

Three generations of the taiga tick Ixodes persulcatus, the descendants from naturally infected females, have been examined by means of dark field and phase contrast microscopies and indirect immunofluorescent reactions with monoclonal antibodies. Location of borreliae in oocytes was examined by means of electron microscopy. The examined ticks derived from 9 females collected in the Novgorod Province, from 6 females of 1st laboratory generation and 5 females of the 2nd generation. In total, 250 larvae, 178 nymphs, 59 females and 70 males of three consequent generation have been examined. Almost 100% of descendants of naturally infected females were infected with Borrelia burgdorferi s. l. and similar infection rate was observed in unfed tick larvae collected in field conditions. The borreliae received transovarially to larvae of the 1st generation then were transmitted to 100% nymphs and imago of this generation and two next generations.

Animals↗
PubMed1998

[The effect of 2 diets on the biological aspects of Blattella germanica (Dictyoptera: Blattellidae) under laboratory conditions].

It was conducted a study of 2 colonies of Blattella germanica (Dictyoptera: Blattellidae) kept since 1994 in the laboratory at 29 +/- 1 degrees C, 70-75% of relative humidity and with different foods: one on a diet without proteins, consisting in portions of potatoes (Solanum tuberosum, L.), ripe banana (Musa paradisiaca, L.) and a sugary solution 10%, and the other with a protein content of 20.45% composed of pulverized and dry laboratory food for rats and a source of water. 6 nymphal stages were found with both types of food. There were determined the times of interchanges and the time of nymphal development, which were much shorter among the nymphs fed with proteins. The longevity of each sex showed no significant differences in connection with the type of food used. The times of appearance and eclosion of the oothecae of each oothecal cycle were determined with both foods. It was found that the females deposited up to 5 oothecae during their lives with the 2 types of diet. The average of nymphs per ootheca among the females fed with proteins was much greater (t = 5.33; p < 0.001). The results of this study show that when the food for B. germanica contains proteins, its nymphal development is faster and its reproductive capacity increases, which means that protein is a necessary nutrient for the diet of this species.

Analysis of Variance↗
PubMed1999

Prevalence of Borrelia burgdorferi sensu lato in Ixodes ricinus ticks (Acari, Ixodidae) in different Polish woodlands.

In 1996-1998, a total of 2285 Ixodes ricinus ticks (1063 nymphs, 637 males, 585 females) were collected from vegetation from 25 different localities in the 8 Polish provinces throughout the country. Ticks inhabited all 25 collection sites. The average number of ticks per collection site was 91.4 +/- 13.7. All 2285 ticks were examined for Borrelia burgdorferi sensu lato (s.l.) presence, of which 1333 specimens from 3 provinces were tested by routine indirect immunofluorescence assay (IFA) using polyclonal antibody PAB 1B29. The remaining 952 specimens from 5 provinces were examined by polymerase chain reaction (PCR), using FL6 and FL7 primers. The overall infection rate in ticks estimated by these 2 methods was 10. 2%. Nymphs showed lower positivity rate (6.2%) as compared to adult ticks (14.9% in females and 12.4% in males). The highest percentage of infected I. ricinus ticks (37.5%) was noted in the Katowice province while the lowest (4.1%) in the Bia ystok province. In particular collection sites, infection rates varied from 0-37.5%. The obtained results confirmed that B. burgdorferi s.l. is present throughout the distributional areas of I. ricinus in Poland and that a prevalence of spirochete-infected ticks may be high in some locations.

Animals↗
PubMed2001

Hosts of the immature stages of the rhinoceros tick, Dermacentor rhinocerinus (Acari, Ixodidae).

The collection of the immature stages of Dermacentor rhinocerinus from host animals is described for the first time. These are the bushveld gerbil (Tatera leucogaster, from which larvae and nymphs were collected, the red veld rat (Aethomys crysophilus), from which a larva was collected, and the Natal multimammate rat (Mastomys natalensis), from which a nymph was collected. The rodents were examined in a nature reserve in which there are white rhinoceroses (Ceratotherium simum).

Animals↗
PubMed2001

Exposure of cattle immunized with different stocks of Theileria parva to buffalo-associated Theileria challenge on two game parks in Zimbabwe.

Eight cattle immunized with cattle-derived Theileria parva Boleni stabilate together with six susceptible controls were released in Dombawera Game Park on the Highveld of Zimbabwe. This coincided with Rhipicephalus appendiculatus nymphal activity. The cattle grazed together with African buffaloes (Syncerus caffer) and were not treated against tick infestation. The nymphal tick infestation was high, and seven of the eight immunized cattle and three of the controls had severe and fatal reactions. Subsequently, two stocks of Theileria parva to be tested for their immunizing abilities were prepared-one from adult ticks which were fed as nymphs on one of the sick control animals (Dom 268) and the other from adult ticks collected from pastures grazed by buffaloes (Bv-1). Two groups of cattle were immunized with either the Dom 268-derived strain (eight animals) or the Bv-1-derived strain (four animals). These together with three non-immunized controls, were released in Bally Vaughaun Game Park in the Highveld, where buffaloes are present, during the season of nymphal tick activity. A third group of five cattle, immunized with stabilate Bv-1, and three non-immunized controls were released at the same site during the season of adult tick activity. The nymphal and adult tick infestations of the cattle were large and more than 2000 nymphs and 1000 adult ticks were counted per animal. Cattle were treated with a pyrethroid pour-on preparation to control the tick infestation and screw-worm strike. The immunized cattle in the three groups survived the theileriosis challenge for a period of 18 months, but the non-immunized control cattle suffered a severe and fatal theileriosis 19-23 days after being placed on the pasture.

Animals↗
PubMedDate not supplied

[Ecology of the tick, Dermacentor silvarum O1].

Results of the experiments have shown that the development of Dermacentor silvarum from egg to imago varied from 44 to 46 days at 28 C and redundant humidity and from 50 to 52 days at 25 degrees C. The thermic threshold of larval development lies within a range of 8.6 degrees C, that of nymphs-9.7 degrees C. A sum of effective temperatures required for larval development averaged 123.5 degrees C, for nymphs-225 degrees C and for the whole ontogenesis-from 570 to 690 degrees C. In the north of the distribution area of D. silvarum this species seems to occur only in those localities, where a sum of effective temperatures is higher than 10 C and makes not less than 570 degrees C.

Animals↗
PubMed1975

[Study of some biological peculiarities of Argas persicus].

It has been found that temperatures ranging from 22 to 38 degrees C are optimal for the development of Argas persicus. Under such conditions the average duration of the whole cycle ranges within the limits of 41 to 133 days. Under conditions favourable for the development of the parasite certain irregularities in the nymph stage of the individual generations have been observed. In some of these up to 97 per cent of the second-stage nymphs transform into imago. This is said to be the main reason for the faster propagation and distribution of the ticks. Adult females that lay eggs for the first time are of considerably higher potential fertility than those that have already passed through several gonotrophic cycles. Under optimal conditions the biologic cycle of the parasite does not discontinue during the whole year. It has been demonstrated that in each feeding the adult ticks engorge about 30 mg of blood and can thus endure fasting for more than 8 years.

Animals↗
PubMed1976

Studies on Theileriidae (Sporozoa) in Tanzania. I. Tick transmission of Haematoxenus veliferus.

Haematoxenus veliferus was experimentally transmitted in cattle on two occasions by the tick Amblyomma variegatum; transmission was transstadial, from nymph to adult. Theileria mutans and Cowdria ruminatium were transmitted at the same time. H. veliferus infected at least 15% of red cells in a splenectomized steer and 10% in a normal steer. One experiment on transstadial transmission from larva to nymph was unsuccessful.

Animals↗
PubMed2002

Individual number change of Empoasca spp. cicadas species in potato.

We investigated the individual number change of Empoasca spp. cicadas species that are living in potatoes for 3 years. We applied the "100 plants" method for the determination for the individual number once per week. Based on the data determined that the settling of adult begins on the last days of May, and valid presence will be followed till the end of the breeding-season. The individual number was gradually increased during the settling, and reached the peak in 1990 on 23 July, in 2000 on 6 August and in 2001 on 22 July. We determined the individuals gathered during the collection. In the population of Empoasca spp. The E. solani Curtis and the E. decipiens Paoli played the dominant role. The E. vitis Göthe was also present with insignificant individual number. Beside the adults many larvae and nymphs were living on the potato which means that the Empoasca spp. Can reproduce also on the potato. At the time of peak individual number in 1999 1876 larvae, 344 nymphs and 400 adults were present on 100 plants, in 2000 (according to the previous order) 3340, 580, 1280, and in 2001 there were 954, 786 and 285. The rainfall in Hungary was disadvantageous in the investigated period, especially the year 2000. During the rain-free period the temperature was high and the relative humidity of the air was low. However, we could state that the increase of the cicada individual number was not restrained by the heat (30-35 degrees C) days. The decrease was in connection with the ageing of the plant stock.

Animals↗
PubMedDate not supplied

[Role of some wild birds and mammals in the natural foci of Crimean haemorrhagic fever in Stavropol' region].

The results of the study on the role of some wild mammals and birds as feeding sources of for ticks Hyalomma marginatum, the main vectors of Crimean haemorrhagic fever virus in the Stavropol Territory, in the preimago phases of their development are presented. These phases (larvae and nymphs) were found on rooks, hooded crows, partridges, European brown hares and eared hedgehogs. The examination of domestic fowl resulted in finding larvae and nymphs in small amounts on turkeys. According to the data of the epizootological survey carried out in summer and autumn of 2000 in the Stavropol Territory, rooks and, to a lesser extent, hares were found to be the main feeding sources for ticks in the preimago phases. Rodents seemed to be of minimal importance as feeding sources under the conditions of the Stavropol Territory. Of all animals, rooks must be the main object in the epizootological survey of the territory.

Animals↗
PubMed2003

Ixodid ticks of angora and boer goats, grysbok, common duikers, kudus and scrub hares in Valley Bushveld in the Eastern Cape Province, South Africa.

At monthly intervals from February 1983 to January 1984 two Angora goats, two Boer goats, one grysbok, Raphicerus melanotis, one common duiker, Sylvicapra grimmia, one greater kudu, Tragelaphus strepsiceros, and four scrub hares, Lepus saxatilis, were killed on a farm in Valley Bushveld in the Eastern Cape Province, South Africa and examined for ticks. Seven ixodid tick species were collected, of which Rhipicephalus glabroscutatum followed by Amblyomma hebraeum and Rhipicephalus oculatus were the most numerous. Amblyomma hebraeum was mainly a parasite of the two goat breeds, with the Angora goats harbouring greater numbers than the Boer goats, while large numbers of R. glabroscutatum parasitized the goats and the antelopes. Rhipicephalus oculatus was nearly exclusively a parasite of scrub hares. The larvae of A. hebraeum were most numerous on goats from May to July, the nymphs from September to November and the adults from August to December and during February, while the immature stages of R. glabroscutatum were most numerous on these animals from April to July and the adults from August to December. Peak activity periods of the latter tick were somewhat longer on kudus than on goats; the immature stages were most numerous from January to August and the adults from July to February. The larvae of R. oculatus were most numerous on scrub hares from March to May, nymphs from September to November and adults from October to December.

Animals↗
PubMedDate not supplied

[Life cycle of Ixodes lividus Koch under the conditions in Leningrad Province].

Under conditions prevailing in the Leningrad region I. lividus has, in general, a one year life cycle. Having engorged on swallows overwintering larvae come off in burrows and in 24-26 days moult for nymphs. In a fortnight after 4-5 day feeding on nestlings the latter transform into imagos. After passing the stages of the postmoulting development (3-4 days), feeding on nestlings (5-7 days), rest (7-8 days) and oviposition (14-18 days) the females die. Larvae of a new generation appear in August-September. However, 2.8 to 6.5% of individuals in a population, due to late feeding of larvae or mortality of hosts, stop in their development at phases of imago and nymph and hibernate together with larvae. In an overwintering population they accounted for 3.4-5.0%.

Animals↗
PubMed1992

Immunization of guinea-pigs and cattle against adult Rhipicephalus appendiculatus ticks using semipurified nymphal homogenates and adult gut homogenate.

Guinea-pigs inoculated with crude homogenate of unfed nymphs of the tick Rhipicephalus appendiculatus and with three semipurified fractions of the homogenate obtained by gel permeation chromatography, acquired a significant degree of immunity to infestation with adults of this tick. Fraction 2 induced the highest reduction (66%) in mean weight of engorged females followed by crude homogenate and fractions 1 and 3. Calves immunized with crude homogenates of unfed nymphs, fraction 2 of nymphal homogenate, and gut homogenate of unfed females also acquired immunity against adults of R. appendiculatus. The mean weight of engorged females fed on calves inoculated with nymphal fraction 2 was the lowest of all five groups of calves on which females fed. The reduction in weight (38%) was not significantly different from that observed for females fed on calves inoculated with crude nymphal homogenate (31%) or females from third infestation of adult ticks. No differences in the weight and hatchability of egg batches produced by engorged females collected from the five groups of calves were observed. Analysis of sera collected from the five groups of calves showed that the concentration of albumin, alpha-1, alpha-2 and beta-globulins fluctuated and no significant differences between the treated groups were observed. The levels of gamma-globulin increased in treated groups including the group inoculated with adjuvant only, but unlike previous reports no increase in gamma-globulin or a correlation between the level of gamma-globulin and the degree of resistance acquired were observed in calves exposed to repeated tick infestations. However, the increase in the concentration of gamma-globulin in calves inoculated with fraction 2 or crude nymphal homogenate was higher than that observed in the other groups.

Animals↗