bluuebunny/crossref_metadata_2025 huggingface dataset:
Cigarette consumption and socio‐economic circumstances in adolescence as predictors of adult smoking
Authors: Jefferis B. , Graham H. , Manor O. , Power C.
Published: December 2003

Aim To investigate effects of cigarette consumption level and socio‐economic circumstances during adolescence on adult smoking.

Methods 1958 British birth cohort (all births 3–9 March 1958). Logistic regression used to predict (i) smoking at 41 years and (ii) persistent smoking (at 23, 33 and 41 years) from cigarette consumption and socio‐economic circumstances at 16 years, indicated by social class and educational qualifications.

Results Of 6537 subjects with full smoking history, 30% smoked at 16 years, 23% smoked at 41 years and 19% smoked at 23, 33 and 41 years (persistent smokers). Heavier smokers at 16, 23 and 33 years were more likely to smoke at 41 years than lighter smokers. The odds ratio (OR) of smoking at 41 years was 2.5 for men and 3.0 for women who smoked ≥60 cigarettes/week at age 16, relative to <20 cigarettes/week. Subjects from manual social backgrounds and those with no qualifications had elevated risks of being a smoker at 41 years or a persistent smoker. These effects were robust to adjustment for adolescent consumption level (e.g. adjusted OR for no qualifications was 3.8). However, adolescent consumption level modified the effect of educational achievements. Among lighter adolescent smokers, those gaining higher qualifications had lower prevalence of smoking at 41 years (16%) than men with no qualifications (83%); among heavier adolescent smokers, prevalence was more similar for subjects with higher (56%) and no qualifications (69%).

Conclusions Socio‐economic background appears to influence adult smoking behaviour separately from adolescent cigarette consumption which is a recognized measure of nicotine dependence. There was some evidence that effects of early nicotine dependence are modified by educational achievements.
The alcohol–tobacco relationship: a prospective study among adolescents in six European countries
Authors: Wetzels J. J. L. , Kremers S. P. J. , Vitória P. D. , De Vries H.
Published: December 2003

Aim  This study examined the earliest stages in drug involvement, in terms of the relationship between alcohol and tobacco use, among adolescents from six European countries (Denmark, Finland, the Netherlands, Portugal, Spain and the United Kingdom). International, gender and age differences were studied.

Design, setting and participants  A large international sample of European adolescents (n = 10170, mean age = 13.3 years) was followed longitudinally. Data were gathered in the autumn terms of 1998 and 1999 by means of self‐administered questionnaires.

Measures  Adolescents’ self‐reports on smoking and alcohol behaviour were used. Both behaviours were classified into two categories, that of adolescents who had never used the substance and that of those who had used the substance at least once in their lives. Logistic regression was used to determine which substance was the best predictor of the subsequent use of the other substance.

Findings  Alcohol use and tobacco use were found to be associated with each other reciprocally. Results revealed that in Europe as a whole, tobacco use predicted subsequent alcohol use better than the converse. However, for Dutch girls, alcohol use predicted subsequent smoking behaviour better than the converse.

Conclusion  The findings suggest that the development of alcohol and tobacco use patterns are closely related, but the order of progression is not universal and may reflect cultural factors.
The role of an international nightlife resort in the proliferation of recreational drugs
Authors: Bellis Mark A. , Hughes Karen , Bennett Andrew , Thomson Roderick
Published: December 2003

Aims  The study compares types, frequencies and quantities of substances used by young people while holidaying in the international dance resort of Ibiza (Spain) with their patterns of use in the United Kingdom. It measures changes in substance use at both locations between 1999 and 2002 and examines the role of dance resorts in recruiting individuals into using new substances.

Design  Data were collected from visitors to Ibiza in 1999 (n = 846) and 2002 (n = 868). Information on drug use was surveyed through a short anonymous questionnaire.

Setting  Individuals were sampled at Ibiza airport just prior to returning to the UK.

Findings  Most individuals visiting Ibiza used illicit drugs in the United Kingdom (57.4% in 2002), with nearly all users continuing to use in Ibiza. Use of most drugs in Ibiza was characterized by binge behaviour, with many individuals using drugs 5 or more nights per week. Proportions using cocaine, ecstasy and GHB have risen significantly (1999–2002) in both locations, as have numbers of ecstasy tablets taken on a usual night. Substance use was associated positively with number of previous visits to Ibiza and new users were recruited into use while abroad (17.4 and 33.1 per 1000 people were introduced to cocaine and ecstasy use, respectively, in Ibiza).

Conclusions  The emergence of international nightlife resorts increasingly links drug use abroad with that in individuals’ countries of origin. Our results indicate that resorts such as Ibiza offer tourists the opportunity to increase levels of drug consumption and try different substances in an atmosphere conducive to experimentation. Patterns of recreational drug use in leading international resorts may help predict developments in drug use elsewhere and as such be an important tool in planning appropriate interventions.
Neighborhood effects on drug reporting
Authors: Richardson Jerome , Fendrich Michael , Johnson Timothy P.
Published: December 2003

Aims  To examine whether neighborhood racial characteristics are associated with the under reporting of life time cocaine/crack use.

Design  A household survey of high‐risk communities with above‐average admissions to state‐supported drug and alcohol treatment programs.

Setting  Chicago, Illinois, USA.

Participants  A total of 303 adults.

Measures  Self‐reported use of cocaine/crack during a respondent's life time, hair test assays for cocaine use and level of neighborhood diversity measured using the Simpson Index.

Findings  Respondents from more segregated neighborhoods were more likely than those from diverse neighborhoods to under report life time cocaine/crack use.

Conclusions  Neighborhood racial characteristics should be considered as an important factor in household surveys on illicit substance use.
Types of natural recovery from alcohol dependence: a cluster analytic approach
Authors: Bischof G. , Rumpf H. ‐J. , Hapke U. , Meyer C. , John U.
Published: December 2003

Background  Social capital and a low severity of alcohol‐related problems have been focused upon to explain the processes of natural recovery from alcohol dependence. However, studies using control groups have not found significant differences in these variables. Subtypes of natural remission which might account for this inconsistency have only been described on grounds of qualitative data.

Aims  To identify subtypes of natural remitters using cluster analysis.

Participants  One hundred and seventy‐eight media‐recruited natural remitters were interviewed personally. Several triggering mechanisms and maintenance factors of remission were assessed using standardized questionnaires. Based on age of onset and severity of dependence, adverse consequences from drinking, social pressure and social support, cluster analyses were performed.

Results  Cluster analyses yielded three groups of natural remitters: one cluster with a high severity of dependence, low alcohol‐related problems and low social support (‘low problems—low support’; n = 65), one group characterized by high severity of dependence, high alcohol‐related problems and medium social support (‘high problems—medium support’; n = 37), and a third group which consisted of subjects with high social support, late age of onset, low severity of dependence, and low alcohol‐related problems (‘low problems—high support’; n = 76). Cluster solutions were confirmed using discriminant analyses. Analyses of variance (ANOVAs) revealed further group differences on other triggering and maintaining factors of remission.

Conclusions  Failure to identify specific pointers to natural recovery in previous research might be due to heterogeneous subgroups of natural remitters. In order to build a conceptual framework for understanding the processes of natural recovery, interactions of different independent variables should be considered.
Cannabis and educational achievement
Authors: Fergusson David M. , Horwood L. John , Beautrais Annette L.
Published: December 2003

Aims  To examine the relationship between cannabis use in adolescence/young adulthood and levels of educational attainment.

Design  Data were gathered over the course of a 25‐year longitudinal study of a birth cohort of 1265 New Zealand children.

Measurements  Measures analysed included (a) frequency of cannabis use in adolescence and young adulthood (15–25 years); (b) levels of educational achievement to age 25 years; and (c) social, family and individual characteristics assessed prior to age 16.

Findings  Increasing cannabis use was associated with increasing risks of leaving school without qualifications, failure to enter university and failure to obtain a university degree. The association between cannabis use and leaving school without qualifications persisted after control for confounding factors. When due allowance was made for pre‐existing levels of cannabis use there was no evidence to suggest the presence of reverse causal pathways in which lower educational achievement led to increased cannabis use.

Conclusions  Findings support the view that cannabis use may act to decrease educational achievement in young people. It is likely that this reflects the effects of the social context within which cannabis is used rather than any direct effect of cannabis on cognitive ability or motivation.
Patterns of over‐the‐counter nicotine gum use: persistent use and concurrent smoking
Authors: Shiffman Saul , Hughes John R. , Di Marino Michael E. , Sweeney Christine T.
Published: December 2003

Aims To examine the occurrence of persistent use (i.e. use beyond 12 weeks) and concurrent use of nicotine gum with cigarettes among consumers who purchase nicotine gum over‐the‐counter (OTC).

Design Assessment of gum use was conducted in the context of a smoking cessation trial among smokers who purchased Nicorette gum and enrolled in the optional Committed Quitters smoking cessation program. Eligible participants were contacted by telephone 6 weeks and 12 weeks following their self‐selected target quit date. Those who reported gum use at 12 weeks were contacted again at week 24.

Participants A total of 2655 current smokers who purchased nicotine gum and enrolled in a clinical efficacy trial of the Committed Quitters program.

Measurements Detailed information on smoking and gum use, including frequency of use, amount used and reasons for use was obtained at each of the three follow‐up assessments.

Findings At the 24‐week assessment, 6% of participants reported current use of nicotine gum (i.e. persistent use). Those engaging in persistent use averaged 4.7 (SD = 2.5) days of gum use per week and 3.2 (SD = 3.5) pieces of gum per day. Sixty‐six per cent of persistent users reported at week 24 that they were not currently smoking, and 67% of persistent users reported they were using gum to establish or maintain abstinence. At the 6‐, 12‐ and 24‐week assessments, 14%, 10% and 2% of participants, respectively, reported current use of nicotine gum and current cigarette smoking (i.e. concurrent users). Those concurrent users reported at the 12‐week follow‐up that they did so an average of 4.4 (SD = 2.1) days per week, that they chewed an average of 2.6 (SD = 3.5) pieces of nicotine gum per day and that they smoked an average of 8.7 (SD = 8.6) cigarettes per day.

Conclusion Extended use of nicotine gum is rare. Concurrent use with cigarettes is uncommon. In both cases, the amount of gum use is small. OTC marketing of nicotine gum does not appear to have increased use contrary to labeling nor resulted in patterns of use that should warrant clinical or public health concerns.
A contextual profile of club drug use among adults in Chicago
Authors: Fendrich Michael , Wislar Joseph S. , Johnson Timothy P. , Hubbell Amy
Published: December 2003

Aims  To better understand the prevalence, correlates, risk factors and context of club drug use among US adults in the City of Chicago.

Design  An Audio Computer‐Assisted Self Interview was administered to a household probability sample of adults, aged 18–40 years, from June 2001 to January 2002.

Setting  Subjects were drawn from randomly selected households using a multi‐stage area probability design.

Participants  The data represent 627 randomly selected adult participants.

Measurement  Weighted prevalence estimates with design‐effect adjusted confidence intervals of life‐time, past 12 month and past 30 day use of any club drug and of specific club drugs; prevalence of rave attendance, other drug use, motivation for use among club drug users; χ2 tests of significance, logistic regression and adjusted odds ratios.

Findings  Overall club drug prevalence rates were nearly twice those obtained for MDMA alone. Club drug users were more likely to use multiple illicit substances and to report having been in treatment for substance use. A majority of life‐time club drug users never attended a rave although rave attendees were more likely to report frequent use of MDMA. Use was associated with gender, race and sexual orientation.

Conclusions  Prevention research should be informed by further population‐based research on club drug use. Research should not focus exclusively on rave attendees, as they are only a subset of club drug users. Research is needed on neurological and behavioral sequelae across different types of club drugs, gender differences in the impact of sexual orientation on club drug risk and on the effects of personality characteristics such as sensation seeking on club drug use behavior.
Mitochondrial and Wolbachia markers for the sandfly Phlebotomus papatasi: little population differentiation between peridomestic sites and gerbil burrows in Isfahan province, Iran
Authors: Parvizi P. , Benlarbi M. , Ready P. D.
Published: December 2003

Abstract.  In Iran, Phlebotomus papatasi (Scopoli) (Diptera: Psychodidae) is the main vector of Leishmania major Yakimoff & Schokhor (Kinetoplastida: Trypanosomatidae), the causative agent of rural zoonotic cutaneous leishmaniasis. This sandfly is abundant both in villages and in the burrows of the main reservoir host, the gerbil Rhombomys opimus (Licht.) (Rodentia: Gerbillidae). Populations of P. papatasi were sampled from the edges of villages in Isfahan province, using CDC miniature light traps in peridomestic sites and sticky papers placed at the entrances to gerbil burrows. Single peridomestic sites in two northern provinces were also sampled. Individual sandflies were characterized by PCR amplification and sequencing of fragments of their mitochondrial cytochrome b gene and of the wsp gene of endosymbiotic Wolbachia pipientis Hertig (alpha‐Proteobacteria: Rickettsiaceae). The distributions of the haplotypes of these two maternally inherited genes were analysed to assess the population differentiation of P. papatasi, knowledge of which will be needed for planning control measures. For the first time these markers were used to characterize P. papatasi from gerbil burrows, and they indicated the absence not only of sympatric cryptic species but also of any long‐term differentiation of lineages in different habitats. A single lineage of cytochrome b haplotypes was found, and both sexes in all populations had a high infection rate of the same A‐group strain of Wolbachia (wPap). The distributions of cytochrome b haplotypes were consistent with females dispersing more than males, which has been reported for P. papatasi in other countries. The widespread distribution of wPap suggests that Wolbachia could be used to spread transgenes between populations of P. papatasi in different habitats.
Molecular identification of some forensically important blowflies of southern Africa and Australia
Authors: Harvey M. L. , Mansell M. W. , Villet M. H. , Dadour I. R.
Published: December 2003

Abstract.  One major aspect of research in forensic entomology is the investigation of molecular techniques for the accurate identification of insects. Studies to date have addressed the corpse fauna of many geographical regions, but generally neglected the southern African calliphorid species. In this study, forensically significant calliphorids from South Africa, Swaziland, Botswana and Zimbabwe and Australia were sequenced over an 1167 base pair region of the COI gene. Phylogenetic analysis was performed to examine the ability of the region to resolve species identities and taxonomic relationships between species. Analyses by neighbour‐joining, maximum parsimony and maximum likelihood methods all showed the potential of this region to provide the necessary species‐level identifications for application to post‐mortem interval (PMI) estimation; however, higher level taxonomic relationships did vary according to method of analysis. Intraspecific variation was also considered in relation to determining suitable maximum levels of variation to be expected during analysis. Individuals of some species in the study represented populations from both South Africa and the east coast of Australia, yet maximum intraspecific variation over this gene region was calculated at 0.8%, with minimum interspecific variation at 3%, indicating distinct ranges of variation to be expected at intra‐ and interspecific levels. This region therefore appears to provide southern African forensic entomologists with a new technique for providing accurate identification for application to estimation of PMI.
In vitro assays for repellents and deterrents for ticks: differing effects of products when tested with attractant or arrestment stimuli
Authors: Mcmahon C. , Kröber T. , Guerin P. M.
Published: December 2003

Abstract.  Most in vivo and in vitro tests with repellents or deterrents against ticks have not considered which sensory channel is being targeted. We have recorded the responses of two hard tick species (Acari: Ixodidae) in vitro to determine if such products can disrupt the perception of an attractant in a repellent assay or the perception of an arrestment stimulus in a deterrent assay. Ethyl butylacetylaminopropionate (EBAAP), N,N‐diethyl‐methyl‐benzamide (deet), permethrin and indalone were chosen to test their capacity to inhibit the attraction of Amblyomma variegatum Fabricius to its aggregation‐attachment pheromone. Vapours of each test product plus those from a synthetic blend of the pheromone were delivered to the walking tick in an air stream on a locomotion compensator. Neither EBAAP, deet, permethrin nor indalone could inhibit attraction of A. variegatum even when each of the test products was delivered at 106 times the pheromone. Indalone did decrease the attraction of A. variegatum to the pheromone and induced repulsion of A. variegatum when presented on its own in the air stream. The effect of permethrin, a sodium channel blocker, was also tested in a deterrent assay measuring the arrestment of Ixodes ricinus (L.) adults on its own faeces and faecal constituents. Permethrin deterred arrestment at doses of 670 fg/cm2 to 67 ng/cm2, i.e. at levels five times lower than the dose of chemostimuli present in the arrestment stimulus. This sensitivity to permethrin suggests that it acts via the contact chemoreception channel.
Phylogenetic status and matrilineal structure of the biting midge, Culicoides imicola, in Portugal, Rhodes and Israel
Authors: Dallas J. F. , Cruickshank R. H. , Linton Y.‐M. , Nolan D. V. , Patakakis M. , Braverman Y. , Capela R. , Capela M. , Pena I. , Meiswinkel R. , Ortega M. D. , Baylis M. , Mellor P. S. , Mordue (luntz) A. J.
Published: December 2003

Abstract.  The biting midge Culicoides imicola Kieffer (Diptera: Ceratopogonidae) is the most important Old World vector of African horse sickness (AHS) and bluetongue (BT). Recent increases of BT incidence in the Mediterranean basin are attributed to its increased abundance and distribution. The phylogenetic status and genetic structure of C. imicola in this region are unknown, despite the importance of these aspects for BT epidemiology in the North American BT vector. In this study, analyses of partial mitochondrial cytochrome oxidase subunit I gene (COI) sequences were used to infer phylogenetic relationships among 50 C. imicola from Portugal, Rhodes, Israel, and South Africa and four other species of the Imicola Complex from southern Africa, and to estimate levels of matrilineal subdivision in C. imicola between Portugal and Israel. Eleven haplotypes were detected in C. imicola, and these formed one well‐supported clade in maximum likelihood and Bayesian trees implying that the C. imicola samples comprise one phylogenetic species. Molecular variance was distributed mainly between Portugal and Israel, with no haplotypes shared between these countries, suggesting that female‐mediated gene flow at this scale has been either limited or non‐existent. Our results provide phylogenetic evidence that C. imicola in the study areas are potentially competent AHS and BT vectors. The geographical structure of the C. imicola COI haplotypes was concordant with that of BT virus serotypes in recent BT outbreaks in the Mediterranean basin, suggesting that population subdivision in its vector can impose spatial constraints on BT virus transmission.
Learning and memory in the mosquito Aedes aegypti shown by conditioning against oviposition deterrence
Authors: Kaur J. S. , Lai Y. L. , Giger A. D.
Published: December 2003

Abstract.  Oviposition site choice by female mosquitoes, Aedes aegypti (L) (Diptera: Culicidae), was affected by rearing them in water treated with 0.016% of the repellent Mozaway™ containing citronella and neem. Given a choice between a bowl of repellent‐treated and a bowl of untreated water, Ae. aegypti reared in untreated water strongly preferred to oviposit on the clean water (93–98%) instead of repellent‐treated water. This demonstrates effective deterrence of oviposition by dilute Mozaway™. Those reared in repellent‐treated water were less deterred: 38–46% of their eggs were laid on the repellent‐treated water and 54–62% on the clean water. Evidently the female mosquitoes reared in repellent‐treated water were conditioned against oviposition site deterrence, as shown when choice tests were conducted 6 days post‐emergence from the treated water. This demonstrates learning and memory in the mosquito Ae. aegypti, with implications for dengue vector surveillance and control.
Geographical and seasonal distribution of the bluetongue virus vector, Culicoides imicola, in central Italy
Authors: De Liberato C. , Purse B. V. , Goffredo M. , Scholl F. , Scaramozzino P.
Published: December 2003

Abstract.  Following the first incursion of bluetongue virus (BTV) into Italy, the geographical and seasonal distribution of the biting midge Culicoides imicola Kieffer (Diptera: Ceratopogonidae), the main vector of BTV and African horse sickness virus, was investigated in two regions of central Italy (Lazio and Tuscany). Surveillance of Culicoides was carried out between July 2001 and December 2002 using light traps: 1917 collections were made in 381 trap sites, well distributed across both regions. During the survey, bluetongue outbreaks were recorded in both regions. Culicoides imicola was found in 89 (23%) trap sites, distributed fairly continuously along the whole western coastline, between 41.2697° N and 44.05724° N. It was found only occasionally inland and usually in low abundance, with catches of more than 1000 specimens per night found in only two sample sites and 74% of catches numbering fewer than 10 specimens. Adults were caught from March to mid December, with peaks ranging from the end of August to mid November. The coastal distribution and the presence of only few sites with year‐round records of adult vectors suggests that colonization may have occurred recently, by passive wind‐dispersal from external source areas (Sardinia and Corsica). Alternatively, the species may occur in established, previously undetected, autochthonous populations that are limited from extension inland and northern‐ward within Lazio and Tuscany by cool winter temperatures.
Vasodilatory activity in horsefly and deerfly salivary glands
Authors: Rajská P. , Pecháňová O. , TAKÁC P. , Kazimírová M. , Roller L. , Vidlicka L , Ciampor F. , Labuda M. , Nuttall P. A.
Published: December 2003

Abstract. Salivary gland extract (SGE) of four horsefly species (Hybomitra bimaculataMacquart,Hybomitra ciureaiSéguy,Tabanus bromiusL.,Tabanus glaucopisMeigen) and one deerfly species (Chrysops relictusMeigen) (Diptera: Tabanidae) were shown to contain vasodilatory activity. Aliquots equivalent to 1, 5 and 10 pairs of salivary glands (SG) relaxed rat femoral artery (with intact endothelium) pre‐constricted with phenylephrine. Vasodilatory activity was dose‐dependent. SGE of one horsefly species (Haematopota pluvialisL.) did not induce relaxation. The kinetics of vasodilation induced by SGE of four horsefly species differed from the deerfly. These results indicate that tabanid species may produce more than one type of vasodilator to aid blood feeding.
Mosquito host‐feeding patterns and implications for Japanese encephalitis virus transmission in northern Australia and Papua New Guinea
Authors: Van Den Hurk A. F. , Johansen C. A. , Zborowski P. , Paru R. , Foley P. N. , Beebe N. W. , Mackenzie J. S. , Ritchie S. A.
Published: December 2003

Abstract.  Japanese encephalitis (JE) virus spread to northern Australia during the 1990s, transmitted by Culex annulirostris Skuse and other mosquitoes (Diptera: Culicidae). To determine the relative importance of various hosts for potential vectors of JE virus, we investigated the host‐feeding patterns of mosquitoes in northern Australia and Western Province of Papua New Guinea, with particular attention to pigs, Sus scrofa L. – the main amplifying host of JE virus in South‐east Asia. Mosquitoes were collected by CDC light traps baited with dry ice and 1‐octen‐3‐ol, run 16.00–08.00 hours, mostly set away from human habitations, if possible in places frequented by feral pigs. Bloodmeals of 2569 mosquitoes, representing 15 species, were identified by gel diffusion assay. All species had fed mostly on mammals: only <10% of bloodmeals were from birds. The predominant species was Cx. annulirostris (88%), with relatively few (4.4%) bloodmeals obtained from humans. From all 12 locations sampled, the mean proportion of Cx. annulirostris fed on pigs (9.1%) was considerably lower than fed on other animals (90.9%). Highest rates of pig‐fed mosquitoes (>30%) were trapped where domestic pigs were kept close to human habitation. From seven of eight locations on the Australian mainland, the majority of Cx. annulirostris had obtained their bloodmeals from marsupials, probably the Agile wallaby Macropus agilis (Gould). Overall proportions of mosquito bloodmeals identified as marsupial were 60% from the Gulf Plains region of Australia, 78% from the Cape York Peninsula and 64% from the Daru area of Papua New Guinea. Thus, despite the abundance of feral pigs in northern Australia, our findings suggest that marsupials divert host‐seeking Cx. annulirostris away from pigs. As marsupials are poor JE virus hosts, the prevalence of marsupials may impede the establishment of JE virus in Australia.
Seasonal dynamics of the Cayenne tick, Amblyomma cajennense on horses in Brazil
Authors: Oliveira P. R. , Borges L. M. F. , Leite R. C. , Freitas C. M. V.
Published: December 2003

Abstract.  The population dynamics of all stages of the Cayenne tick, Amblyomma cajennense (Fabricius) (Acari: Ixodidae) on horses was evaluated over a period of 2 years in the district of Pedro Leopoldo, State of Minas Gerais, Brazil. Every 14 days, the left side of 20 horses was brushed for collection of immature stages; counts of adults were also undertaken. Infestation by larvae was detected from April to August, whereas nymphs were observed from June to October. Infestation by adults was detected throughout the year, and the highest population density occurred from September to March. The number of males was always higher than the number of females, but with considerable reduction in the male : female ratio between April and July. It was observed that 25% of the horses carried 41% of the infesting ticks, and 20% carried only 10% of the ticks during the entire period of the study.
Anopheles arabiensis and An. quadriannulatus resistance to DDT in South Africa
Authors: Hargreaves K. , Hunt R. H. , Brooke B. D. , Mthembu J. , Weeto M. M. , Awolola T. S. , Coetzee M.
Published: December 2003

The malaria control programme of KwaZulu‐Natal Province, South Africa, includes Mamfene and Mlambo communities. Western‐type houses there are currently sprayed with deltamethrin, whereas traditional houses are sprayed with DDT for malaria control. In 2002, mosquitoes of the Anopheles gambiae complex (Diptera: Culicidae) were collected from DDT‐sprayed houses, by window exit traps, and from man‐baited nets outdoors. Larval collections were also carried out at Mzinweni Pan near Mlambo. Species of the An. gambiae complex were identified by rDNA polymerase chain reaction assay. The majority of samples collected by window trap and baited nets were identified as the malaria vector An. arabiensis Patton, with a few An. merus Dönitz and An. quadriannulatus (Theobald). The larval collections were predominantly An. quadriannulatus with a small number of An. arabiensis. Standard WHO insecticide susceptibility tests using 4% DDT and 0.05% deltamethrin were performed on both wild‐caught females and laboratory‐reared progeny from wild‐caught females. Wild‐caught An. arabiensis samples from window traps gave 63% and 100% mortality 24‐h post‐exposure to DDT or deltamethrin, respectively. Wild‐caught An. arabiensis samples from man‐baited net traps gave 81% mortality 24‐h post‐exposure to DDT. The F1 progeny from 22 An. arabiensis females showed average mortality of 86.5% 24‐h post‐exposure to DDT. Less than 80% mortality was recorded from five of these families. Biochemical analyses of samples from each of the families revealed comparatively high levels of glutathione‐S‐transferases and non‐specific esterases in some families, but without significant correlation to bioassay results. Wild‐caught An. quadriannulatus larvae were reared through to adults and assayed on 4% DDT, giving 47% (n = 36) mortality 24‐h post‐exposure. Finding DDT resistance in the vector An. arabiensis, close to the area where we previously reported pyrethroid‐resistance in the vector An. funestus Giles, indicates an urgent need to develop a strategy of insecticide resistance management for the malaria control programmes of southern Africa.
Seasonal abundance patterns of the sandfly Phlebotomus papatasi in climatically distinct foci of cutaneous leishmaniasis in Israeli deserts
Authors: Wasserberg G. , Yarom I. , Warburg A.
Published: December 2003

Abstract.  Among foci of cutaneous leishmaniasis in Israel, population densities of the vector sandfly Phlebotomus papatasi Scopoli (Diptera: Psychodidae) were assessed during April–October 1999 in the mesic Negev desert and the hyper‐xeric Arava valley, using sticky traps placed overnight near host burrows of the fat sand rat, Psammomys obesus Cretzschmar (Cricetidae: Gerbillinae). Population dynamics of Ph. papatasi differed between the Negev (study sites on sand near Mount Keren and on loess at Nizzana ruins) and the Arava valley (study sites on sand at Shezaf and in a fallow field near irrigation at wadi Arava). At the Negev sites, sandfly abundance peaked in spring (April or May), whereas at Arava sites Ph. papatasi population densities were bi‐modal, with peaks in both spring and autumn (September or October). This might be conducive to sustaining enzootic Leishmania major Yakimoff & Schokhor (Kinetoplastida: Trypanosomatidae). In both areas, Ph. papatasi densities were much higher at the site with moister soil, raising transmission risks of zoonotic cutaneous leishmaniasis.
Multiplex PCR assay for malaria vector Anopheles minimus and four related species in the Myzomyia Series from Southeast Asia
Authors: Phuc H. K. , Ball A. J. , Son L. , Hanh N. V. , Tu N. D. , Lien N. G. , Verardi A. , Townson H.
Published: December 2003

Abstract.  Mosquitoes (Diptera: Culicidae) of the Anopheles (Cellia) Myzomyia Series are important malaria vectors in Africa, India and Southeast Asia. Among 10 named species of Myzomyia known from the Oriental Region, seven form the An. minimus group. Even for expert taxonomists, the adults of these species remain difficult to identify morphologically. For technical staff of malaria control programmes, confusion may extend to misidentification of species that are not formally within the minimus group. For identification of specimens from Indochina (Cambodia, Laos, Vietnam), we describe a multiplex polymerase chain reaction (PCR) assay, based on rDNA internal transcribed spacer 2 (ITS2) sequences, that employs a cocktail of primers to identify An. minimus Theobald sibling species A and C (sensu; Green et al., 1990) and three other species in the An. minimus group (An. aconitus Dönitz, An. pampanai Büttiker & Beales, An. varuna Iyengar), as well as An. jeyporiensis James, also belonging to the Myzomyia Series. As the test is DNA‐based, it can be applied to all life stages of these mosquitoes for ecological investigations and vector incrimination studies. This PCR assay is simpler, quicker, cheaper and more readily interpreted than previous assays.
First finding of Dirofilaria repens in a natural population of Aedes albopictus
Authors: Cancrini G. , Romi R. , Gabrielli S. , Toma L. , DI Paolo M. , Scaramozzino P.
Published: December 2003

Abstract.  The invasive mosquito Aedes albopictus (Skuse) (Diptera: Culicidae) has become widespread in Italy during the past decade. Also Italy has foci of canine filariasis caused by Dirofilaria (Spirurida: Onchocercidae), due to subcutaneous D. repens Railliet & Henry as well as the dog heartworm D. immitis (Leidy) transmitted by various vector mosquitoes (Diptera: Culicidae). In 2002, at Fiumicino, west of Rome (Lazio Region), 17% of dogs were found to have D. repens microfilariae in peripheral blood. To evaluate the role of Ae. albopictus as a vector of Dirofilaria in this area, female mosquitoes were collected daily, June–October 2002, landing on dog or human bait in a rural house at Focene. Mosquitoes were maintained at 27°C and 70% RH for 6 days, to allow development or purging of filaria larvae, then identified and frozen for subsequent molecular assay with filaria‐specific ribosomal S2‐S16 primers. To distinguish specimens harbouring infective L3 Dirofilaria larvae, DNA was extracted separately from the mosquito abdomen and head‐thorax. Dirofilaria species were identified by sequencing, confirmed by polymerase chain reaction of positive specimens using primers specific for D. immitis and D. repens. Dirofilaria DNA was detected in 3/154 (2%) of Ae. albopictus females examined: D. repens DNA in head‐thorax and abdomen of one collected 27th July; D. immitis in the abdomen of one collected 24th September; DNA of both D. immitis and D. repens in the head‐thorax of one collected 11th October 2002. Thus Ae. albopictus is a potential vector of both Dirofilarias in Italy, representing risks for veterinary and human health.
Mitochondrial diversity ofMusca domesticahousefly populations in the Asian and western Pacific biogeographical regions
Authors: Marquez J. G. , Bangs M. J. , Krafsur E. S.
Published: December 2003

Abstract. Houseflies (Musca domesticaL., Diptera: Muscidae) are cosmopolitan, colonizing, and eusynanthropic. Their distribution in the Malaysian archipelago provides an opportunity to study successive waves of colonization and extinction during the Pleistocene and Recent epochs. We scored single‐strand conformation polymorphisms (SSCPs) at16S2andCOIImitochondrial loci in 47 housefly samples from the Australian, Austro‐Malayan, Indo‐Malayan, Manchurian and Indo‐Chinese subregions of Wallace's zoogeographical classification. We discuss the results in light of the Pleistocene vs. post‐Pleistocene dispersal and faunal exchange in the Asia‐Pacific area. Fourteen haplotypes were detected, of which 10 were confined to a single subregion. No haplotype was ubiquitous and only one was found in four subregions. Population diversity,HS, was greatest in the Indo‐Malayan (0.36) and heterogeneous among subregions. The mean subregional diversity was 0.21 ± 0.03, representing the probability that two randomly chosen flies, from any subregion, had different haplotypes. The hierarchical partition of diversity indicated restricted maternal gene flow among subregions (GRT = 0.60,Nm∼ 0.32). These results suggest long‐standing genetic isolation of houseflies in the Malaysian archipelago and support the hypothesis that they dispersed widely during the Pleistocene. Haplotypes common among mainland populations but shared with island groups in low frequencies (<1%) indicate surprisingly little recent gene flow.
Reduced seroprevalence of Kaposi's sarcoma‐associated herpesvirus (KSHV), human herpesvirus 8 (HHV8), related to suppression of Anopheles density in Italy
Authors: Coluzzi M. , Calabrò M. L. , Manno D. , Chieco‐Bianchi L. , Schulz T. F. , Ascoli V.
Published: December 2003

Abstract.  In two formerly malarious parts of Italy, age‐related seroprevalence rates of Kaposi's sarcoma‐associated herpesvirus [human herpesvirus 8 (KSHV/HHV8)] were determined from local blood donors and correlated with periods of vector control during anti‐malaria campaigns. In Veneto, decreased KSHV/HHV8 seroprevalence in the 1951–1955 birth cohort coincides with the peak of DDT house‐spraying. In Sardinia, where larviciding augmented indoor DDT‐spraying, a significant drop of KSHV/HHV8 seroprevalence between 1945 and 1950 and 1951–1955 birth cohorts (P = 0.0046) coincides with suppression of the malaria vector Anopheles labranchiae Falleroni (Diptera: Culicidae). These results are consistent with age‐related association between KSHV/HHV8 seroprevalence rates in native/resident populations and the density of malaria vectors in Veneto and Sardinia. This example supports our ‘promoter arthropod’ hypothesis on the role of haematophagous insects [putatively blackflies (Simuliidae), sandflies (Phlebotominae) and biting midges (Ceratopogonidae), as well as mosquitoes] when their bites induce hypersensitivity and immunosuppression, potentiate KSHV/HHV8 transmission via human saliva (when insect bite lesions are licked by another person whose saliva carries the virus) and may facilitate Kaposi's sarcoma.
Oral susceptibility of South African Culicoides species to live‐attenuated serotype‐specific vaccine strains of African horse sickness virus (AHSV)
Authors: Paweska J. T. , Prinsloo S. , Venter G. J.
Published: December 2003

Abstract.  The oral susceptibility of livestock‐associated South African Culicoides midges (Diptera: Ceratopogonidae) to infection with the tissue culture‐attenuated vaccine strains of African horse sickness virus (AHSV) currently in use is reported. Field‐collected Culicoides were fed on horse blood‐virus mixtures each containing one of the seven serotype‐specific vaccine strains of AHSV, namely serotypes 1, 2, 3, 4, 6, 7 and 8. The mean titres of virus in the bloodmeals for the seven vaccine strains were between 6.8 and 7.6 log10TCID50/mL. All females (n = 3262) that survived 10 days extrinsic incubation (10 dEI) at 23.5°C were individually assayed in microplate BHK‐21 cell cultures. In midges tested immediately after feeding, AHSV was detected in 96.1% individuals; mean virus titre was 2.0 log10TCID50/midge. After 10 dEI virus recovery rates varied in Culicoides (Avaritia) imicola Kieffer from 1% (AHSV‐2) to 11% (AHSV‐7) and in Culicoides (A.) bolitinos Meiswinkel from 0% (AHSV‐3) to 14.6% (AHSV‐2). Although our results indicate that two major field vectors C. imicola and C. bolitinos are susceptible to oral infection with vaccine strains of AHSV, the level of viral replication for most of the vaccine strains tested was below the postulated threshold (=2.5 log10TCID50/midge) for fully disseminated orbivirus infection. In this study, for the first time AHSV has been recovered after 10 dEI from six non‐Avaritia livestock‐associated Old World species: C. engubandei de Meillon (AHSV‐4), C. magnus Colaço (AHSV‐3, ‐4), C. zuluensis de Meillon (AHSV‐2, ‐4), C. pycnostictus Ingram & Macfie (AHSV‐2), C. bedfordi Ingram & Macfie (AHSV‐7), and C. dutoiti de Meillon (AHSV‐7). As little is known about the virogenesis of AHSV in the southern African species of Culicoides, the epidemiological significance of our findings in relation to the potential for transmission of current AHSV vaccine strains by Culicoides requires further assessment.
Naturally acquired antibody responses to the components of the Plasmodium falciparum merozoite surface protein 1 complex
Authors: Wang Lina , Crouch Lucy , Richie Thomas L. , Nhan Doan Hanh , Coppel Ross L.
Published: December 2003

Merozoite surface protein 6 (MSP6) and 7 (MSP7) of Plasmodium falciparum are peripheral membrane proteins whose cleaved products, MSP636, MSP722 and MSP719, are found on the merozoite surface as components of a non‐covalently bound complex which also contains four polypeptides derived from merozoite surface protein 1 (MSP1). We have expressed both the precursor regions and the processed mature products of MSP6 and MSP7 in Escherichia coli and showed that these recombinant proteins react with human immune sera. In a set of sera collected from individuals living in malaria‐endemic areas of Southern‐central Vietnam, antibodies to the mature polypeptides of MSP636 and MSP722 were detected in 50·6 and 85·6% of the serum samples, whereas antibodies to the precursor regions of MSP6 and MSP7 were detected in only 12·1 and 42·5% of the serum samples, respectively. The predominant subclass of anti‐MSP6 antibodies was IgG1, whereas the predominant subclass of anti‐MSP7 antibodies was IgG3. In the same set of serum samples, the antibody responses to MSP119 are predominantly IgGI, whereas antibodies to merozoite surface protein 4 (MSP4) are mainly IgG3. This data is consistent with the proposition that, during malaria infection, variable proteins induce responses that are predominantly of the IgG3 isotype, and conserved proteins induce responses that are predominantly IgG1. The antibodies to MSP6, MSP7 and MSP119 all decreased at the time of infection, but increased during the convalescent period. No correlation was observed between the antibodies at the commencement of the study and absence of parasitaemia during surveillance in this population.
Local skin reaction (chancre) induced following inoculation of metacyclic trypanosomes in cattle by tsetse flies is dependent on CD4 T lymphocytes
Authors: Naessens Jan , Mwangi Duncan M. , Buza Joram , Moloo Shamshudeen K.
Published: December 2003

The first visible response in livestock to the bite of a trypanosome‐infected tsetse fly is the formation of a localized skin reaction, also known as a chancre. This is an inflammatory response in the skin associated with swelling and an influx of cells. It is thought to be associated with an acquired immune response to the injected metacyclic trypanosomes. In this study, we examined the role of T lymphocytes in the development of the inflammatory response, by depleting cattle of T cell subpopulations and monitoring the development of chancres. Depletion of CD4 cells, but not CD8 cells, resulted in a significant reduction in chancre formation, confirming that an acquired response mediates the inflammatory response. In addition, it was established that the CD4 T cells mediate the generation of memory for immunity to a homologueous re‐challenge. The inflammatory response in the skin did not affect further progress of the infection.
In vivo activation of murine peritoneal B1 cells by the filarial nematode phosphorylcholine‐containing glycoprotein ES‐62
Authors: Wilson Emma H. , Katz ElaD. , Goodridge Helen S. , M. Harnett Margaret , Harnett William
Published: December 2003

Mice were subcutaneously implanted with osmotic pumps loaded with ES‐62, an immunomodulatory phosphorylcholine (PC)‐containing glycoprotein secreted by filarial nematodes. The concentration of ES‐62 was set to give a serum level within the range found for PC‐containing molecules during natural filarial nematode infection of humans. Peritoneal B1 cells were recovered from the mice and the effect of exposure to ES‐62 on a number of parameters determined ex vivo. B1 cells exposed to ES‐62 showed an increase in spontaneous proliferation that was enhanced by ex vivo exposure to F(ab′)2fragments of anti‐IgM antibodies (anti‐IgM), to activate via the antigen receptor, or LPS. Consistent with this, cell‐cycle analysis indicated that cells pre‐exposed to ES‐62 showed increased cell‐cycle progression following stimulation with anti‐IgM. Pre‐exposed cells also showed an increase in both spontaneous and anti‐IgM induced IL‐10 secretion. Taken together, these data indicate that ES‐62 activates murine B1 cells in vivo. Conversely, we have previously shown conventional (B2) B cells to be rendered hypo‐responsive by in vivo exposure to ES‐62 and the different effect on the two cell types is discussed in relation to the nature of the antibody response arising during filarial nematode infection.
A DNA‐prime/protein‐boost vaccination regimen enhances Th2 immune responses but not protection following Schistosoma mansoni infection
Authors: DA’Dara Akram A. , Skelly Patrick J. , Walker Christine M. , Harn Donald A.
Published: December 2003

DNA immunization represents a promising vaccine strategy that has been reasonably successful, and will likely play an even greater role in vaccine development as these vaccines continue to be improved. We have developed a partially protective DNA vaccine against schistosome infection based on a 23‐kDa integral membrane protein, Sm23. The focus of this study was to compare immunogenicity and efficacy of vaccination regimens utilizing Sm23 DNA vaccine alone vs. regimens that utilized both Sm23 DNA and Sm23 in recombinant protein form. We found that priming and boosting with the Sm23 DNA construct (Sm23‐pcDNA) resulted in a significant level of protection against challenge infection (36–44%). In contrast, altering this protocol by changing the boost from Sm23 DNA to boosting with recombinant Sm23 protein (rSm23) formulated in aluminium hydroxide (alum) failed to induce a significant reduction in worm burdens. Similarly, mice primed and boosted with the rSm23 in alum also did not develop significant levels of protection against challenge infection. We hypothesize that the differences in the ability to drive protective immunity using the DNA prime‐DNA boost strategy and the inability to do so when recombinant Sm23 in alum was substituted for Sm23 DNA is due to driving of different immune responses. In support of this, we found that mice primed and boosted with Sm23‐pcDNA had Th1‐type immune responses characterized by low anti‐Sm23 IgG1 : IgG2a antibody isotype ratios, whereas mice boosted with rSm23 had higher IgG1 : IgG2a ratios. In addition, priming and boosting with rSm23 elicited mainly IgG1 antibodies with no detectable IgG2a, indicative of a polarized Th2‐type immune response. Thus, similar to our earlier work, the results of this study show that protective vaccination using Sm23 is associated with a Th1 immune response, and efficacy is diminished using protocols that diminish this Th1 bias. In our study, this was likely due to the use of the Th2‐driving adjuvant alum, and future studies are planned where we will compare the protective efficacy of rSm23 administered with Th1‐type adjuvants.