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PubMed1997

A generic population model for the African tick Rhipicephalus appendiculatus.

We present a simulation population model for the African tick Rhipicephalus appendiculatus, based on previous analyses of the mortality factors most closely correlated with observed population changes at 11 sites in equatorial and South Africa. The model incorporates temperature-dependent rates of egg production and development, climate-driven density-independent mortality rates, particularly during the adult-larval stage, and density-dependent regulation of both nymphs and adults. Diapause is also included for tick populations in southern Africa. The model successfully describes both the seasonality and annual range of variation in numbers of each tick stage observed at each of 4 test sites in Uganda, Burundi and South Africa. Sensitivity analysis showed that the final version of the model is robust to 4-fold variation in most parameter values (that were per force based on informed guesses), but is more sensitive to the regression coefficients determining density-dependent interstadial mortality (that were derived from analysis of field data). The model is able to predict the seasonality of ticks from a site in Kenya where a full prior population analysis was not possible because only adults and nymphs had been counted. The model is potentially applicable to other species of ticks, both tropical and temperate, to predict tick abundance and seasonality as risk factors for tick-borne diseases.

Animals↗
PubMed1999

Borrelia burgdorferi sensu lato in Ixodes ricinus ticks and rodents in a recreational park in south-western Ireland.

Ixodes ricinus ticks infected with Borrelia burgdorferi sensu lato were numerous on the edges of paths and roads in a recreational park in south-western Ireland. The abundance of ticks at different sites was related to the presence of deer, but a negative relationship was shown between tick abundance and tick infection rates. This is thought to be due to the deposition of large numbers of uninfected ticks by deer, which are apparently not good reservoir hosts of B. burgdorferi s.l. Blood meal analysis only detected deer DNA in uninfected nymphs. Reservoir competent rodents, Apodemus sylvaticus and Clethrionomys glareolus, were abundant at all sites and a high proportion of captured specimens were infested with larval ticks. However, very few rodents were infected with B. burgdorferi s.l. and none of the unfed infected nymphs analysed for the identity of their larval blood meal had fed on rodents. The spirochaetes detected in I. ricinus in the study area may be poorly adapted to rodents or are not transmitted readily because of the absence of nymphal infestation. The majority of spirochaetes in these ticks were apparently acquired from non-rodent hosts, such as birds.

Animals↗
PubMed1999

Selection of virulent isolates of entomopathogenic hyphomycetes against Clavigralla tomentosicollis Stål. and evaluation in cage experiment using three cowpea varieties.

The virulence of 8 isolates of entomopathogenic hyphomycetes against adult and 5th instar nymph of Clavigralla tomentosicollis was evaluated in the laboratory at 4 different concentrations of inoculum. At all concentrations, Beauveria bassiana CPD 9 and Metarhizium anisopliae CPD 5 caused the highest mortality in adult bug ranging from 58 to 97% and 53 to 100%, respectively at 7 days post inoculation. The same isolates had the shortest LT50 (3.5 and 4.1 days, respectively) and the lowest LC50 (1.8 x 10(5) and 9.8 x 10(4) conidia ml-1) values in adult insects. In nymphs, M. anisopliae CPD 5 was the most virulent isolate causing mortality of between 43 to 92% with the shortest LT50 of 2.7 days and the lowest LC50 of 4.6 x 10(5) conidia ml-1 which however did not differ significant from LC50 observed in B. bassiana CPD 9 isolate at 5 days post inoculation. A significant reduction in feeding in both developmental stages treated with fungi was observed at 2 days after treatment with the greatest reduction occurring in insects treated with B. bassiana CPD 9 and M. anisoplia CPD 5. In adult insects treated with these isolates, some bugs ceased feeding 24 h before death. When these two isolates were compared in caged experiment with an untreated control using a susceptible, tolerant and moderately resistant variety of cowpea, percentage pod and seed damage were significantly lower in fungal treated cages than in the control cages on all varieties tested. Grain yield per plant was also significantly higher in fungal treated cages than in the control cages on all varieties. The performance of M. anisopliae CPD 5 was however superior to B. bassiana CPD 9. Application of the fungi on moderately resistant variety of cowpea was found to enhance the performance of the pathogen.

Heteroptera↗
PubMed1997

The distribution and prevalence of B. burgdorferi genomospecies in Ixodes ricinus ticks in Ireland.

Questing Ixodes ricinus ticks were collected from six locations throughout Ireland and 638 nymphs, 111 females and 118 males were investigated for infection with Borrelia burgdorferi sensulato (s.l.). The total prevalence of B. burgdorferi s.l. in the ticks was determined as 14.9% by polymerase chain reaction (PCR) amplification of the spacer region of 5S-23S rRNA genes. Infection prevalence was significantly higher in adult (20.1%) Ixodes ricinus compared to nymphs (13.1%). The prevalence of infection in adult male and female ticks was similar (19.5% and 20.7% respectively). The genomospecies B. burgdorferi sensu stricto, B. afzelii, B. garinii and group VS116 were identified by reverse line blot (RLB) using genomospecies specific oligonucleotide probes. The most prevalent B. burgdorferi genomospecies identified were VS116 (34.6%), B. garinii (24.3%) and B. burgdorferi sensu stricto (18.4%). B. afzelii was uncommon (6.6%). Multiple infections were observed in 13.2% of the infected ticks. The distribution of the genomospecies showed geographical variation and also seemed to be influenced by the nature of the habitat. A broad range of genomospecies seemed to be associated with the presence of a wide spectrum of potential reservoir hosts in the habitat and also with a high overall prevalence of B. burgdorferi s.l.

Animals↗
PubMed2001

Sequestration of host plant-derived compounds by geometrid moth, Milionia basalis, toxic to a predatory stink bug, Eocanthecona furcellata.

A predatory stink bug, Eocanthecona furcellata, died after feeding on Milionia basalis larvae. The compounds toxic to E. furcellata were isolated from the hemolymph of M. basalis larvae and identified as inumakilactone A, nagilactone C, and nagilactone C glucoside. The concentrations of inumakilactone A, nagilactone C, and nagilactone C glucoside in the hemolymph of the final instar larvae were 130, 50, and 770 microg/ml, respectively. Nagilactone C showed the highest insecticidal activity against second-instar nymphs of E. furcellata, while nagilactone C glucoside showed the lowest, one twentieth of that of nagilactone C. When mixed compounds were given at the same concentrations as those in hemolymph of M. basalis, all nymphs of E. furcellata died with in three days. Inumakilactone A and nagilactone C were found to be in the leaves of podocarp, Podocarpus macrophyllus, the only host plant of M. basalis, at concentrations of 13 and 175 microg/g fresh weight, respectively. However, no nagilactone C glucoside was detected in the leaves of this species. These results suggested that M. basalis may transform nagilactone C to its glucoside.

Animals↗
PubMed2001

Evidence for the utility of the Bm86 antigen from Boophilus microplus in vaccination against other tick species.

The Bm86 antigen, as originally identified in Boophilus microplus, is the basis of commercial tick vaccines against this tick species. The potential for using this antigen or homologues of the antigen in vaccination against other tick species has been assessed. We have conducted vaccine trials in cattle using the B. microplus-derived recombinant Bm86 vaccine (TickGARD) using pairs of vaccinated calves and control calves. These were infested with B. microplus and Boophilus decoloratus larvae simultaneously. For both species, the numbers of engorged female adult ticks, their weight and egg-laying capacity were all reduced, leading to a reduction in reproductive capacity of 74% for B. microplus and 70% for B. decoloratus. Hyalomma anatolicum anatolicum ticks were fed both as immatures as well as adults on vaccinated calves and non-vaccinated controls. There was an overall 50% reduction in the total weight of nymphs engorging on vaccinated calves, and a suggestion of a subsequent effect on feeding adults. For Hyalomma dromedarii there was a 95% reduction in the number of nymphs engorging and a further 55% reduction in weight of those ticks surviving. Rhipicephalus appendiculatus and Amblyomma variegatum ticks were fed simultaneously both as immatures and subsequently as adults. There was no evidence for a significant vaccination effect. Finally, the amino acid sequence of a Bm86 homologue found in H. a. anatolicum unequivocally demonstrated the conservation of this molecule in this species. Our strategy for the development of multivalent anti-tick vaccines is discussed in relation to these findings.

Amino Acid Sequence↗
PubMed2001

Breast cancer in Rubens paintings.

Rubens was one of main baroque painters who practices realism, which means that he painted whatever his eyes capture. That fact has helped us with the visual aspect and the circumstances where such paintings were painted. This has allowed us to discover alterations in the breast of the models he painted, which suggest breast cancer. Such painting are 'The three Graces', 'Diana and her nymphs pursued by satyrs', 'Orpheus and Euridice'. In 'The three Graces' we can see that the model on the right has an open ulcer with reddening of the skin, nipple retraction, reduction of breast volume as well as axilar lymph nodes. This is a visual aspect of a locally advanced breast cancer. In Diana and her nymphs pursued by satyrs and in Orpheus and Euridice we can see a breast retraction in the same place as in 'The three Graces', which suggest breast cancer indirectly. The analysis of the tumor mass in the models of these pictures allow us to know more on the works, the social environment and the diseases happened in the years this painter lived.

Breast Neoplasms↗
PubMed1997

Detection of Theileria annulata by the PCR in ticks (Acari:Ixodidae) collected from cattle in Mauritania.

We report on the detection of Theileria annulata in infected Hyalomma ticks by the PCR using primers derived from the gene encoding the 30 kDa major merozoite surface antigen (TamsI-1). No inhibition of the PCR was observed and as little as 0.1 pg of parasite DNA, corresponding to 12 sporozoites, could be detected in non-infected tick DNA samples, spiked with T. annulata genomic DNA. Hyalomma dromedarii ticks, fed on a calf experimentally infected with T. annulata, were used to validate the PCR further. The infection rate in the adult ticks, fed as nymphs during the febrile reaction, was high (62%), dropped to zero for 1 day in tick batches that engorged after treatment with Butalex and increased to 30% 2 days later and 38% of the ticks acquired the infection after feeding as nymphs during a carrier state piroplasm parasitaemia of less than 0.1%. As an internal control, 16S tick rDNA sequences could be amplified from T. annulata-negative tick samples. Finally, 202 adult ticks from Mauritania, collected from zebu cattle carrying low levels of Theileria piroplasms, were tested by the PCR. Thirty-eight out of 52 (73%) and 17 out of 30 (57%) H. dromedarii from the Gorgol and Trarza regions, respectively and two out of 30 (7%) Hyalomma marginatum rufipes from the Gorgol region were positive. Hyalomma marginatum rufipes, Rhipicephalus evertsi evertsi and Rhipicephalus guilhoni from the Trarza region were negative. These findings confirm that H. dromedarii is the main vector of T. annulata in Mauritania and that the PCR is a useful method of determining the infection rates in ticks collected from cattle carrying low levels of T. annulata piroplasms.

Animals↗
PubMed2002

Lygus hesperus feeding and salivary gland extracts induce volatile emissions in plants.

Induction of plant volatiles by leaf-chewing caterpillars is well documented. However, there is much less information about volatile induction by insects with different feeding habits. We studied the induction of plant volatiles by a piercing-sucking insect, the western tarnished plant bug Lygus hesperus Knight. Adults of both genders and nymphs of Lygus induced the local emission of a blend of volatiles from both cotton and maize. Feeding by Lygus also induced the systemic emission of volatiles that was similar but less complex than the blend emitted at the site of feeding. Infestation by mated, mature adult females (>4 days old), but not by nymphs or mature males, caused detectable emission of alpha-pinene, myrcene. and (E)-beta-caryophyllene, compounds that are stored in the glands of cotton tissue. This indicated that damage to glands in the petiole and leaf by the female ovipositor, rather than feeding, contributed significantly to the emission of these volatiles. Girdling the plant stem to disrupt phloem transport markedly decreased the movement of 14C-labeled photosynthetic products to the apex of the plant, and this treatment also markedly reduced the amount of systemically induced volatiles caused by Lygus feeding. Lygus salivary gland extracts were capable of inducing emission of the same volatile blend as measured for plants infested by feeding insects or treated with volicitin. an elicitor isolated from caterpillar regurgitant. The results indicate that L. hesperus is capable of inducing the emission of plant volatiles and that induction is caused by an elicitor that is contained in the insect salivary gland.

Animals↗
PubMed2003

Hosts and distribution of Amblyomma auricularium (Conil 1878) and Amblyomma pseudoconcolor Aragão, 1908 (Acari: Ixodidae).

Collections of Amblyomma auricularium (Conil 1878) and A. pseudoconcolor Aragão, 1908 are discussed in relation to distribution and hosts. Three tick collections (two from Argentina and a third from the USA) house a total of 574 A. auricularium (307 males, 162 females, 73 nymphs and 32 larvae) and 179 A. pseudoconcolor (96 males, 74 females, 4 nymphs and 5 larvae). Apart from an adult A. pseudoconcolor found on a bird, Nothura maculosa Temminck, 1815, all ticks were found on mammals. The great majority of specimens of both ticks species were removed from the family Dasypodidae Gray, 1821 (84.9% and 93.8% of A. auricularium and A. pseudoconcolor, respectively). Amblyomma auricularium has also been found on wild hosts of the families Myrmecophagidae and occasionally Didelphidae, Caviidae, Chinchillidae, Hydrochaeridae, Muridae, Canidae, Mustelidae, Procyonidae and domestic animals (cattle, dogs, horses), while A. pseudoconcolor has also been found occasionally on wild hosts of the family Didelphidae and on domestic animals (cattle, dogs). Amblyomma pseudoconcolor appears to be restricted to the Neotropical region, covering northern Argentina and the eastern region of South America from Uruguay to Surinam, including south-eastern Paraguay, eastern Brazil and French Guiana. Amblyomma auricularium is distributed from northern Patagonia in Argentina throughout the Neotropics into the Nearctic region up to the southern USA (Texas, Florida), with collection localities also in Belize, Bolivia, Brazil, Colombia, Costa Rica, French Guiana, Honduras, Mexico, Nicaragua, Panama, Paraguay, Trinidad & Tobago, Uruguay and Venezuela. It is not known whether A. auricularium is an established resident of the USA.

Animals↗
PubMed2002

Control of Ixodes scapularis and Amblyomma americanum through use of the '4-poster' treatment device on deer in Maryland.

Deer self-treatment devices ('4-posters') were evaluated for their efficacy in reducing populations of blacklegged ticks, Ixodes scapularis, and lone star ticks, Amblyomma americanum. At each of three locations in Maryland, 25 '4-posters' were operated in study areas of approximately 5.18 km2. Populations of host-seeking ticks were monitored by flagging of treated areas and similar untreated control areas without '4-posters.' From 1998 to 2002 the percent mortalities achieved were 69, 75.8 and 80 at the three study sites infested with I. scapularis nymphs, and 99.5 and 95.3 for A. americanum nymphs at the two sites where this species occurred.

Animals↗
PubMed2003

Factors affecting mite herbivory on eggplants in Brazil.

The objective of this study was to determine effects of total rainfall, mean temperature, predators, height of canopy, levels of nitrogen and potassium in leaves, and the density of leaf trichomes on the attack intensity of Tetranychus evansi and T. urticae (Acari: Tetranychidae) and Aculops lycopersici (Acari: Eriophyidae) in five plantations of the eggplant Solanum melongena var. 'Natu Nobilis' in two regions of Brazil. Higher numbers of individuals of A. lycopersici, T. evansi and T. urticae/cm2 were observed on eggplants in the Municipality of Guidoval than in Viçosa which might be explained by the fact that Guidoval showed hotter and more rainy weather. A. lycopersici was positively correlated with mean temperature (r=0.54, P=0.03), and T. evansi was positively correlated with total rainfall (r=0.54; P=0.04), while for T. urticae the correlation with total rainfall was almost significant (r=0.47, P=0.055). No significant effects were found (P>0.05) of natural enemies, levels of N and K and leaf trichome density on population densities of mites. A. lycopersici showed higher density on the apical leaves while nymphs and adults of T. evansi and eggs of T. urticae had higher numbers on leaves of the apical and medium parts of eggplants than on the lower leaves. Nymphs and adults of T. urticae showed higher attack intensity on leaves from the medium and lower thirds of the plants.

Brazil↗
PubMed2004

Comparative studies on the infectivity of Theileria parva in ticks fed in vitro and those fed on cattle.

Nymphs of the brown ear tick, Rhipicephalus appendiculatus, were fed on heparinised bovine blood infected with Theileria parva parasites in an in vitro feeding system consisting of rabbit skin membranes. The main feeding and development parameters such as the mean attachment rate, feeding duration and engorgement weights of membrane-fed ticks were not significantly different from nymphs fed on cattle. The moulting rate was also comparable although a slight significant difference was observed. Assessment of infection prevalence and abundance with T. parva in adults indicated that the membrane-fed ticks acquired infection to the same level as those fed on cattle. Stabilates prepared from both the membrane- and cattle-fed adult ticks were found to be infective and caused severe reactions in susceptible cattle. When the immunised cattle were challenged with a lethal homologous dose of T. parva (Marikebuni), they were found to be immune.

Animals↗
PubMed2004

The predatory mite Typhlodromus pyri (Acari: Phytoseiidae) causes feeding scars on leaves and fruits of apple.

Typhlodromus pyri Scheuten (Acari: Phytoseiidae) is the most important predator of Panonychus ulmi (Koch) (Acari: Tetranychidae) in orchards and vineyards. It was recently found that adult T. pyri females cause microscopic scars on apple leaves. The present laboratory experiments were carried out to confirm the production of scars on apple leaves and to assess if females cause scars on fruits as well. Scar production on apple leaves and/or fruits was investigated under various nutritional conditions: no food, pollen of Scots pine (Pinus sylvsestris L.) only, nymphs of P. ulmi only, and pollen + prey. Both on leaves and fruits, either offered alone or in combination, feeding scars were produced under all nutritional conditions, but mostly in the 'no food' treatment. The predators consumed significantly more P. ulmi nymphs when offered alone than when offered in combination with pollen. T. pyri laid eggs under all nutritional conditions, but mostly in the 'pollen + prey' treatment and least when no food was offered. T. pyri females caused scars on both leaves and fruits when offered simultaneously, but more on leaves than on fruits. The scars were also bigger on leaves than on fruits in all experiments. T. pyri survived and reproduced on plant material in the absence of other food sources. Whether the scars produced on leaves and fruits harm the quality of fruits or the yield of apple cannot be concluded from the present experiments.

Animals↗
PubMed2004

Effects of purified persimmon tannin and tannic acid on survival and reproduction of bean bug, Riptortus clavatus.

We evaluated the effects of tannic acid and purified perrsimmon tannin on survival and reproduction of bean bugs, Riptortus clavatus.Feeding behavior of R. clavatus was also examined on sweet (cv. Fuyu) and astringent (cv. Chongdosi) persimmon fruits. Soluble tannin in sweet persimmon fruits decreased from 3% in early June to 0.5% in late September, but it increased from 2 to 8% during the same period in astringent persimmon fruits. More bugs visited sweet than astringent persimmon. Numbers of piercing/sucking spots were higher on sweet than on astringent persimmon. When fed 1 and 3% solutions of persimmon tannin, adult bugs ingested only 64.1 and 9.5% of the amount of water ingested by those offered the control (distilled water). Amounts of persimmon tannin ingested by the adult bugs were 6.5 and 2.8 times higher at 1 and 3% tannin solutions compared to a 0.1% solution. Persimmon tannin exerted negative effects on survival and reproduction of R. clavatus at higher concentrations (1 and 3% solutions). Feeding of R. clavatus adults decreased with increasing tannin concentrations. When results from both sexes were pooled, 50% mortality was achieved at 11 and 4 days after treatment with the 1 and 3% tannin solutions, respectively. Reproduction decreased with 1% tannin, and no eggs were produced with 3% tannin solution. Tannic acid was similar in its effects on R. clavatus. All nymphs died 14, 12, and 7 days after feeding on 0.1, 1, and 3% tannic acid, respectively. Adults were less sensitive than nymphs, and their survival was not affected by 0.1% tannic acid. However. 1 and 3% tannic acid solutions were fatal. Survivorship decreased to 50% at 11 and 6 days after supplying tannin solutions of 1 and 3% concentrations. Higher concentrations (1 and 3%) resulted in reduced reproduction, as was seen with persimmon tannin. Our data may explain why R. clavatus does not invade sweet persimmon orchards until late July, when concentrations of soluble tannin are low enough to allow them to feed.

Animals↗
PubMed2001

Th2 polarization of the immune response of BALB/c mice to Ixodes ricinus instars, importance of several antigens in activation of specific Th2 subpopulations.

BALB/c mice were infested with Ixodes ricinus larvae, nymphs or adults. Expression of IL-4 and IFN-gamma mRNA in axillary and brachial draining lymph node cells were measured by competitive quantitative reverse transcription-polymerase chain reaction 9 days after the beginning of primary-infestation. IL-4 mRNA was always higher than that of IFN-gamma mRNA for all tick instars. Moreover, IL-4 mRNA expression progressively increased during nymphal primary-infestation with a high burst of expression 7 days after the beginning of infestation. No evolution of IFN-gamma mRNA expression was detected. Draining lymph node cells of infested BALB/c produced higher level of IL-4 than IFN-gamma following in vitro restimulation with adult tick saliva, salivary gland extract (SGE) or with five selected different chromatographic fractions of SGE. Anti-tick IgG1 antibodies but no IgG2a were detected in BALB/c pluri-infested with I. ricinus nymphs, which confirmed the Th2 polarization of the immune response.

Animals↗
PubMed2003

Selection by phage display of a variant mustard trypsin inhibitor toxic against aphids.

The mustard trypsin inhibitor, MTI-2, is a potent inhibitor of trypsin with no activity towards chymotrypsin. MTI-2 is toxic for lepidopteran insects, but has low activity against aphids. In an attempt to improve the activity of the inhibitor towards aphids, a library of inhibitor variants was constructed and cloned into the pRlac3 phagemid vector. The library of 9.3 x 107 independent colonies was created by randomisation of a stretch of five consecutive codons in the reactive site. Repeated selection rounds against bovine trypsin and chymotrypsin allowed the identification of novel, MTI-2 derived, antitrypsin and antichymotrypsin inhibitors. Chy8, the selected variant with highest affinity for bovine chymotrypsin (Ki = 32 nm versus >1000 nm for the wild-type) represents the strongest known recombinant chymotrypsin inhibitor of the MTI-2 family. It is highly toxic to nymphs of the aphid Acyrthosiphon pisum, and moderately toxic to nymphs of Aphis gossypii and Myzus persicae. The LC50 of 73 microg ml-1 towards A. pisum is the lowest value known among chymotrypsin inhibitors. The aphicidal activity of Chy8 was improved eightfold compared to the wild-type inhibitor. This demonstrates, for the first time, that bovine chymotrypsin provides a useful template to select engineered proteins highly toxic against these aphids. The selected gene will allow the development of transgenic crops that are protected against sucking insect pests.

Amino Acid Sequence↗
PubMed2002

Pathological differentiation of suspected cases of pentastomiasis in China.

We report nine cases of suspected pentastomiasis from China, and propose that diagnosis of this rare parasitic disease should be made aetio-pathologically, subaetio-pathologically, and presumptively. In none of our cases' lesions we could find either a whole or part of an embedded nymph; hence, no aetio-pathologic diagnosis of pentastomid infection was established. In three cases, subaetio-pathologic diagnoses of pentastomiasis were made upon the discovery of a peculiar set of relics from lesions, namely two pairs of circumoral hooks of pentastomid from lesions. In one of these three cases, an extra scissors-like image indicating a longitudinal section of a hook of the embedded pentastomid nymph, probably Linguatula serrata, was found. In the other six cases, none of the relics of the aetiological agents were found, and our diagnoses were made presumptively by a series of relatively specific pathologic features, i.e. pearly lesions over the peritoneal surface of the abdominal cavity under the serosa of the intestinal wall or under the capsules of liver and spleen. They tend to be uniquely protuberant, sometimes linked by a short thin stalk to the surface. The hyalinization and calcification of these centrally caseated granulomatous nodules tend to be concentric and targetoid in appearance. Tuberculosis, the most easily confused condition, was easily ruled out pathohistologically. We believe that there is a need for presumptive pathologic diagnosis of human pentastomid infection not only in China, but worldwide.

Aged↗