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PubMed2004

Studies on the occurrence of Gram-negative bacteria in ticks: Ixodes ricinus as a potential vector of Pasteurella.

A total of 372 Ixodes ricinus ticks (101 females, 122 males, and 149 nymphs) collected by flagging in 6 mixed woodlands of eastern Poland were examined by culture for the presence of internal Gram-negative bacteria other than Borrelia burgdorferi. Adult ticks were examined in pools of 2 specimens each and nymphs were examined in pools of 3-5 specimens each. Ticks were disinfected in 70 % ethanol and homogenized in 0.85% NaCl. The diluted homogenate was inoculated onto 3 kinds of agar media: buffered charcoal yeast extract (BCYE-alpha) for isolation of fastidious Gram-negative bacteria, eosin methylene blue agar (EMB) for isolation of enterobacteria, and tryptic soya agar for isolation of all other non-fastidious Gram-negative bacteria. The Gram-negative isolates were identified with the API Systems 20E and NE microtests. A total of 9 species of Gram-negative bacteria were identified, of which the commonest were strains determined as Pasteurella pneumotropica/haemolytica, which were isolated on BCYE-alpha agar from ticks collected in all 6 examined woodlands. The total number of these strains (49) exceeded the total number of all other strains of Gram-negative bacteria recovered from ticks (30). Of the total number of examined ticks, the minimum infection rate with Pasteurella pneumotropica/haemolytica was highest in females (18.8%), and slightly lower in males (12.3%) and nymphs (10%). Besides Pasteurella pneumotropica/haemolytica, the following species of Gram-negative bacteria were isolated from examined ticks: Pantoea agglomerans, Serratia marcescens, Serratia plymuthica on EMB agar and Aeromonas hydrophila, Burkholderia cepacia, Chromobacterium violaceum, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia on tryptic soya agar. Minimal infection rates with these bacteria were low, ranging from 0.7-5.9%. Of the isolated bacteria, Chromobacterium violaceum, Pasteurella pneumotropica/haemolytica, Pseudomonas aeruginosa, and Serratia marcescens are potentially pathogenic for man and/or animals. In particular, the common occurrence of Pasteurella pneumotropica/haemolytica in Ixodes ricinus ticks poses a potential risk of pasteurellosis for humans and animals exposed to tick bites.

Animals↗
PubMed2005

[Control effects of Mikania micrantha alcohol extract on citrus red mite Panonychus citri].

This study showed that spraying 0.2 and 0.4 g x L(-1) Mikania micrantha alcohol extracts on Panonychus citri could significantly decrease the survival rates of P. citri eggs, larvae and nymphs, and 0.1 g x L(-1) M. micrantha alcohol extract could also significantly decrease the survival rates of larvae and nymphs. In a no-choice test, both the fecundity and the longevity of female P. citri fed on the leaves treated with all three test concentrations 0.1, 0.2 and 0.4 g x L(-1) of M. micrantha alcohol extracts were significantly reduced, compared with those fed on alcohol-treated leaves. In a field experiment, the efficacy of M. micrantha alcohol extracts at three test concentrations was compared with water, alcohol, and 15% Pyridaben, an acaricide widely used in commercial control of red mite in sweet orange orchards. The survival rates of P. citri eggs, larvae and nymphs in all three M. micrantha treatments were lower than the control, and the interference index of population control (IIPC) was 0.518, 0.292 and 0.277, respectively, while the IIPC for the Pyridaben treatment was 0.945, with a control efficacy of only 5.52%. M. micrantha extract had an increased control effect with its increasing concentration, and was safer to natural enemies than 15% Pyridaben. The leaves in the three M. micrantha treatments were less damaged, and their color was much deeper than that of the other three treatments. Therefore, M. micrantha alcohol extract provided a better control of citrus red mite populations than Pyridaben.

Animals↗
PubMed1991

Spatial and temporal dispersion of immature Ixodes dammini on Peromyscus leucopus in northwestern Illinois.

Infestation by immature Ixodes dammini and infection by Borrelia burgdorferi of the white-footed mouse Peromyscus leucopus were studied in Castle Rock State Park in northwestern Illinois during June-October 1990. Prevalence and intensity of infestation of larvae on mice were highest in August with a smaller peak in early June. The distribution of larvae on mice was highly aggregated during each of the sampling periods. Aggregation appears to be the result of a series of nonrandom successful attachments by single larvae, rather than of simultaneous attachment by clumps of larvae. Infection rate of mice by B. burgdorferi averaged 21.4% with a peak of 28.6% in August. A comparison of the numbers of attached immature ticks collected from mice and of questing ticks collected through dragging indicated that the larvae-to-nymph ratio was higher on mice than on drags. Given the low total numbers of nymphs collected from mice, this suggests a potential role for other hosts of I. dammini nymphs in northwestern Illinois.

Animals↗
PubMed1989

Observations on the occurrence and maturation of the nematode Rhabdochona denudata (Dujardin, 1845) in Chub, Leuciscus cephalus (L.), of the Rokytná River, Czechoslovakia.

From October 1985 until July 1987, the seasonal dynamics of Rhabdochona denudata in its principal definitive host, the chub (Leuciscus cephalus), was studied in the Rokytná River (the Danube basin), Czechoslovakia. Prevalence (overall prevalence 77%) and intensity of infection (1-59 nematodes per fish) in the fish were high all year, with both abiotic and biotic factors influencing the fluctuations. Maximum values of prevalence (82-87%) were found in the fish with body length exceeding 20 cm; the mean intensity was highest in the size-group of fish 20-25 cm long, whereas its values gradually decreased in larger fish, this being due to the choice of food by fish of different size-groups. In contrast to the situation in other localities, an annual maturation cycle was not evident and egg-producing female nematodes were present in fish throughout the year. New infections in fish were most common in summer but occurred all year round. This life history pattern seems to be mainly due to the availability of infected ephemeropteran intermediate hosts during all seasons, in this case the nymphs of Ephemera danica, a species noted for its two-year development. In this locality, specifically not determined Rhabdochona larvae were recorded from the mayfly nymphs Ephemera danica (0.4%), Ecdyonurus aurantiacus (7%), and Caenis macrura (10%). The diet of the chub included mayfly nymphs at all seasons.

Animals↗
PubMed1987

The efficacy of alternative routes for the infection or vaccination of animals with Cowdria ruminantium.

The efficacy of subcutaneous, intramuscular and intraperitoneal inoculation of heartwater infective blood or nymph suspensions was tested in 5 experiments involving a total of 199 sheep. The success rate of subcutaneous injections varied greatly (0-100%) in the different groups. However, it was found that certain additives to the inoculum, such as dimethyl sulphoxide or uninfective brain tissue, increased the efficacy of the subcutaneous route. Indications are that the site of inoculation and especially the dose volume are important factors in the success rate of such inoculations. Intramuscular injection with infective nymph suspensions containing bradikynin or hyaluronidase produced heartwater reactions in 11 out of 14 sheep. In 2 experiments, involving 25 cattle, it was found that, although very few animals showed definite reactions after the subcutaneous or intramuscular injection of nymph suspension and additives, the majority were afterwards immune to challenge. This phenomenon, which was also present in some sheep, needs further investigation.

Animals↗
PubMed1986

Dot-ELISA assessment of guinea pig antibody responses to repeated Dermacentor andersoni infestations.

Acquired resistance to ixodid tick infestation is expressed by cattle and laboratory animals. Humoral factors appear to be involved in host acquired resistance to tick bite; however, specific immune responses have yet to be fully characterized. This study examined tick resistance expressed by Hartley guinea pigs upon repeated infestation with Dermacentor andersoni, and describes longitudinal development of antigen specific immunoglobulin over approximately 180 days. Guinea pigs were infested either 4 times with D. andersoni adults, or twice with nymphs. Both infestation groups, adults and nymphs, demonstrated a significant level of resistance to re-infestation, following initial exposure. Dot enzyme-linked immunosorbent assay (Dot-ELISA) was employed to detect antibody reactive with D. andersoni salivary gland antigens (SGA). Animals infested with adults had antibody that increased at a relatively constant rate until the fourth infestation, which was differentiated by a sharp increase in titer, that was maintained for approximately 2 wk. Guinea pigs that received nymph infestations had SGA-specific antibody; however, titers were lower than those in the adult infestation group. Antibody levels continued to increase approximately 80 days beyond the final (second) infestation for this group. A direct correlation between resistance and antibody titer was not evident, since resistance was relatively stable after the second infestation in both infestation groups, and tick-specific immunoglobulin levels continually increased.

Animals↗
PubMed1986

Continued functioning of the feeding apparatus during moulting of Boophilus microplus as an adaptation of one-host ticks.

Nymphs of the 1-host cattle tick Boophilus microplus remain attached to the host during moulting, but this process is not uniform throughout the tick tissues. The muscles of the pharynx and salivarium remain attached to the cuticle and are functional while the cuticle of the legs has already separated from the underlying epidermis and muscle. The nymphs continue to feed for 2 days after the moulting process in the legs has begun, and they more than double their weight in this time. Mouth-part primordia of the adults develop while the nymphs are still feeding. These adaptations could be an advantage of a 1-host feeding strategy, as they decrease the non-feeding development time spent on the host. In the 3-host tick Haemaphysalis longicornis, which moults off the host, the pharynx, salivarium and legs all begin the moulting process at the same time.

Animals↗
PubMed1979

[Biochemistry of the developmental cycle of Triatoma infestans (Vinchuca). 2. Biosynthesis of fatty acids].

The biosynthesis of fatty acids in Triatoma infestans was studied in all the nymph stages and adult insects by feeding experiments with 1-14C acetate. In other experiments labeled acetate, 1-14C palmitate or 1-14C stearate were injected in the abdomen. In another group of experiments the abdominal non intestinal tissue of adult insects was homogenized and the supernatants of 10 000 X g and 105 000 X g were incubated with 1-14C acetyl-CoA. The incorporation of the labeling in the fatty acids was studiel by gas liquid radiochromatography. It was proved that the supernatant of 105 000 X g possessed a fatty acid synthetase able to synthesize de novo the saturated fatty acids of 10 to 18 carbons with a maximal yield in the myristic and palmitic acids. The fatty acid synthetase was active from Nymph L stage. The supernatant of 10 000 X g was able to synthesize fatty acids tentatively identified as eicosenoic and eicosadienoic acids. The T. infestans has also an enzyme that elongated palmitate to stearate. In the fraction precipitable between 10 000 X g and 105 000 X g was apparently present a desaturating enzyme that converts saturated to monoethylenic acids. The enzyme was apparently only active from Nymph II stage.

Acetates↗
PubMed1979

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.

Animals↗
PubMed1967

Isolation of tick-borne encephalitis virus from Ixodes ricinus ticks in the Tribec region.

An attempt has been made to isolate the tick-borne encephalitis virus from nymphs and adults of the tick Ixodes ricinus in the Tribec region. In 1963 no virus was found in 2715 nymphs and 998 adults from various parts of the region, but in 1964, from 2153 unfed ticks collected in the spring, two strains of virus were isolated from the 798 nymphs and two from the adults (one from 647 males and one from 708 females). Thus, on average, 0.2% of the ticks in the region were infected; in the elementary foci of Topol'cianky and Jelenec, where the virus-containing ticks were found, the proportion varied between 0.4% and 0.8%. In 1964 no viruses having a cytopathic effect on chick-embryo-cell cultures were isolated from I. ricinus ticks, in contrast to the isolation of nine such strains in the previous year. The significance of these results in relation to the interstadial transmission of tick-borne encephalitis virus is discussed.

Animals↗
PubMed1981

[A study on the transmission (transstadial, transovarial) of Babesia microti, strain "Hannover i", in its tick vector, Ixodes ricinus (author's transl)].

Transstadial, transovarial and combined transstadial-transovarial transmission of Babesia microti in its tick vector, Ixodes ricinus, was studied. The ticks used (larvae, nymphs, females) were part of the progeny of nymphs collected in an area nearby Hanover. Specimens to be infected alimentarily were fed on parasitaemic Golden Hamsters (Mesocricetus auratus). The ability to infect mammalian hosts of a tick stage was examined by feeding it on negative Golden Hamsters. B. microti was found to be transmitted transstadially from the alimentarily infected larva to the following nymphal stage, only. Thus, this nymph is the only stage transmitting the Babesia to mammalian hosts. Transovarial transmission could not be observed.

Animals↗
PubMed1980

Experimental transmission of African swine fever virus by Ornithodoros coriaceus, an argasid tick indigenous to the United States.

Three ticks, indigenous to the United States, were assessed for their ability to maintain and transmit African swine fever virus (ASFV). Amblyomma americanum and A cajennense adults and nymphs maintained virus for 4 to 7 days after engorging on infected swine blood; however, virus was not carried through the subsequent molt of nymphs and it was not transmitted vertically to the eggs and larvae of the infected females. On refeeding of the ticks, infection was not transmitted to healthy swine. Ornithodoros coriaceus adult females also did not show transovarial transmission of two strains of ASFV. Nymphs, however, maintained virus for 77 to 118 days through a molting stage and transmitted one strain of the virus (Lisbon 60) to healthy swine.

African Swine Fever↗
PubMed1994

[Stegomyian indices and epidemiological status of yellow fever in a rural area of the Ivory Coast].

The M'bahiakro region, located in the center of Ivory Coast and inhabited by the N'gain, has been the scene of a yellow fever epidemic since 1982. This region reunites all the conditions for cyclic emergence of the flavivirus given the current epidemiologic pattern of yellow fever in Africa. In view of this situation ORSTOM, in collaboration with the Pasteur Institute of Ivory Coast, has created a pilot zone for epidemiologic surveillance of yellow fever in this region. The N'gain region which has a total population of 12,000 living in 20 villages with between 100 and 2000 inhabitants is located in a preforest area with an attenuated transitional climate characterized by a dry season and a rainy season with two peak periods of precipitation (May and October) but a low mean annual rainfall (1172 mm). There are few springs, wells and rivers and maintaining water supplies is difficult. As a result villagers stockpile rainwater in various types of containers. Inspections were carried out from February to July in the 20 villages of the region. Each room of every dwelling was registered and visited. Water reserves were inspected and those containing pre-imaginal stage Culicidae were counted as positive. Nymphs and larva were sometimes collected. Nymphs were raised and larva preserved. Species identification by the laboratory was based on these larva and imagos obtained by raising the nymphs. Correspondence tables established by the World Health Organization between stegomiyan indices (dwelling), container, BRETEAU) and flavivirus in the population were used to exploit the results.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

[Colonization of artificial ecotopes by Panstrongylus megistus in Santa Catarina Island, Florianópolis, Santa Catarina, Brazil].

The aim of this work was to verify the colonization of Panstrongylus megistus on artificial ecotopes in Florianópolis, in the Santa Catarina Island, South Brazil. For this purpose 443 houses of the Lagoa district and 779 house annexes (524 chicken-houses, 46 corrals and 209 storage-houses) in 9 different places were examined from 1985 to 1992. These ecotopes, which include ceilings and basements, were checked after application of dislodging liquid (Pirisa 5%). Colonization by P. megistus was verified in two houses, three chicken-houses and one storage-house of the Lagoa district, where eggs, nymphs and adults were collected. To verify local reports of P. megistus occurrence, another two houses and one school were investigated. The colonization at all of these places was confirmed. In the 9 artificial ecotopes examined, 559 eggs, 305 nymphs and 24 adults were collected. The infection rate of P. megistus by Trypanosoma cruzi was 55.3% (182/329). A similar infection rate of 56.5% (78/138) was obtained in adults of P. megistus from sylvatic ecotopes and in adults captured in the houses by the inhabitants between 1983 to 1991. Precipitin tests revealed blood from just one source in 94.0% of the insects (170/181). Human blood was found in 80.6% (25/31) of the adults and in 5.8% (1/17) of the nymphs captured in the houses. These results suggest the need to ally serious epidemiologic vigilance to the effort of the inhabitants in order to avoid the risk of domiciliation of P. megistus in the houses.

Animals↗
PubMed1993

Ixodes ricinus immatures on birds in a focus of Lyme borreliosis.

The infestation of birds by immature Ixodes ricinus was studied during 6 months in a Swiss woodland, where Lyme borreliosis is endemic. Thirteen passerine species were found to be parasitized by I. ricinus subadults and specially Turdus merula, T. philomelos and Erithacus rubecula. Overall, 300 larvae and 162 nymphs were collected on 95 avian hosts. Prevalence of infestation of nymphs on birds was higher in spring; larvae peaked in summer. The infection of birds by Borrelia burgdorferi was also studied using blood cultivation and examination of ticks. Motionless spirochetes were isolated from two E. rubecula. Infected ticks were removed from five species of passerines, and mainly three species of Turdidae (T. merula, T. philomelos and E. rubecula). Infection rate of larvae and nymphs by spirochetes averaged 16.3% and 21.7%, respectively. These percentages, compared to the infection rate of questing ticks collected through dragging, suggest that some Turdidae may play a role as amplifying hosts for spirochetes in the focus.

Animals↗
PubMed1996

Ticks parasitizing humans in Georgia and South Carolina.

From 1990 through 1995, 913 ticks removed from 460 human patients in Georgia or South Carolina were identified and recorded. The majority of these specimens (758, 83.0%) were lone star ticks, Amblyomma americanum. One hundred and four (11.4%) American dog ticks Dermacentor variabilis, 36 (3.9%) blacklegged ticks Ixodes scapularis, 9 (1.0%) Gulf coast ticks Amblyomma maculatum, and 6 (0.7%) brown dog ticks Rhipicephalus sanguineus were also recovered. All active stages (larvae, nymphs, and adults) of A. americanum were represented, whereas nymphs and adults of D. variabilis and I. scapularis and only adults of A. maculatum and R. sanguineus were recorded. Compared with data published for other regions in the U.S.A., A. americanum was a much more prevalent parasite of humans in the current survey. Only 1 (3%) of the I. scapularis collected was a nymph. Because these tick species are vectors of zoonotic pathogens or cause tick paralysis in humans, the data have epidemiological significance.

Adolescent↗
PubMedDate not supplied

[Propagation of the pathogen of Lyme disease Borrelia burgdorferi in the ticks Ixodes persulcatus].

An increase of the number of Borrelia burgdorferi s. l. in nymphs was observed 3-4 months later the moulting and during the following 4-5 months. The percent of infected ticks remained unchanged. The reproduction of spirochete was going not only at a room temperature, but also at a lower temperature, 3-5 degrees (imitation of hibernation conditions). An increase of the spirochete density was especially well marked, when the ticks were maintained under fluctuated daily conditions. We have found out the difference in the transphase transmission. Almost all larvae and nymphs infected by a bloodsucking retained spirochetes after moulting (the first transphase transmission). When the nymphs infected at larval stage were fed on an uninfected mouse, only 30% of imago ticks retained the spirochetes (the second transphase transmission).

Animals↗
PubMed1996

Nymphal development of the auditory system in the praying mantis Hierodula membranacea Burmeister (Dictyoptera, Mantidae).

Like other praying mantises, Hierodula membranacea has a single midline ear on the ventral surface of the metathorax. The ear comprises a deep groove with two tympana forming the walls. A tympanal organ on each side contains 30-40 scolopophorous sensillae with axons that terminate in the metathoracic ganglion in neuropil that does not match the auditory neuropil of other insects. Nymphal development of the mantis ear proceeds in three major stages: 1) The tympanal organ is completely formed with a full complement of sensillae before hatching; 2) the infolding and rotations that form the deep groove are completed primarily over the first half of nymphal development; and 3) over the last five instars (of ten), the tympana thicken and broaden to their adult size and shape, and the impedance-matching tracheal sacs also enlarge and move to become tightly apposed to the inner surfaces of the tympana. Auditory sensitivity gradually increases beginning with the fifth instar and closely parallels tympanum and tracheal sac growth. Late instar nymphs have auditory thresholds of 70-80 dB sound pressure level (SPL). Appropriate connections of afferents to a functional interneuronal system are clearly present by the eighth instar and possibly much earlier. The pattern of auditory system ontogeny in the mantis is similar to that in locusts and in noctuid moths, but it differs from crickets. In evolutionary terms, it is significant that the metathoracic anatomy of newly hatched mantis nymphs matches very closely the anatomy of the homologous regions in adult cockroaches, which are closely related to mantises but are without tympanal hearing, and in mantises that are thought to be primitively deaf.

Acoustic Stimulation↗