bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detection of Plasmodium sporozoites in mosquitoes by polymerase chain reaction and oligonucleotide rDNA probe, without dissection of the salivary glands
Authors: STOFFELS J. A. W. , LEEUWEN W. M. DOCTERS VAN , POST R. J. 
Published: March 2008

AbstractDried Anopheles gambiae mosquito head + thorax portions, infected with Plasmodium falciparum sporozoites, were processed by the polymerase chain reaction. The PCR product was hybridized to an oligonucleotide probe (known as 114R or AW34) diagnostic for Plasmodium. The detection level by autoradiography was ten sporozoites per mosquito. Head + thorax of mosquitoes that contained mature P.falciparum oocysts, without sporozoites, gave no positive signal, indicating that the test detects only infective mosquitoes. This test can be applied to wild mosquito specimens collected, prepared and processed at different time intervals. The technique is convenient, highly sensitive, and could be used with a non‐radioactive detection system and specific probes to differentiate Plasmodium spp.
Exposure of Gambian children to Anopheles gambiae malaria vectors in an irrigated rice production area
Authors: LINDSAY S. W. , SCHELLENBERG J. R. M. ARMSTRONG , ZEILER H. A. , DALY R. J. , SALUM F. M. , WILKINS H. A. 
Published: March 2008

Abstract. Variation in exposure of children to malaria vectors of the Anopheles gambiae complex was recorded in a Gambian village situated near an irrigated area of rice cultivation. Observations were made in 1987 and 1988 during two dry seasons, when pumped water was used to grow rice, and two rainy seasons, when rice was produced using a combination of irrigated and rainfed paddies. Routine collections of mosquitoes were made from under bednets. Most of these specimens were assumed to have fed on the occupants of the net and thus represented a crude measure of exposure to malaria. Most nets in the village were in good condition, but even these were a poor defence against blood‐seeking mosquitoes.Two annual peaks in the numbers of An. gambiae s.l. corresponded with the irrigation of rice paddies in the dry and wet seasons. When there were few vectors in the village the frequency distribution of mosquitoes caught under nets was described best by a Poisson process. When high numbers were present the daily distributions were over‐dispersed and fitted a negative binomial model. The spatial distribution of mosquitoes varied between dry and wet seasons and was related to the predominant wind direction at night, suggesting that wind assisted the dispersal of mosquitoes from their breeding sites.For individual children in the rainy season, increased exposure to malaria vectors was associated with living adjacent to a mosquito breeding site, being resident in larger compounds, having open eaves in the house, a store‐room adjacent to the bedroom, the absence of a ceiling in the bedroom, the absence of wood smoke indoors and leaving the bednet untucked at night. In the dry season a high level of exposure was associated with living close to a mosquito breeding site, having an unfenced compound, sleeping in a room without a ceiling and using insecticide aerosols. These observations demonstrate that within a village there are systematic and persistent differences in the level of exposure to malaria parasites experienced by individual children.
The effect of female body size on male mounting behaviour in Dermacentor variabilis and D. andersoni
Authors: HAMILTON J. G. C. , SONENSHINE D. E. 
Published: March 2008

Abstract. This study was undertaken to determine if body size of female ticks was an important factor in eliciting the mating behaviour of Dermacentor variabilis and D. andersoni males. Dummy female ticks (DFTs) representing varying sizes of feeding females were prepared from plastic beads. Size of DFT was shown to be important in determining both the time spent by males in contact with DFTs and the extent of male mating response released. Dermacentor varlabilis males preferred the smaller‐sized DFT, whereas D. andersoni males preferred the larger sizes. Males of both species were able to discriminate between size of DFT only when mounting sex pheromone (MSP) was present.Size of the DFT was more important than the composition of the MSP extract in determining the time males spent in contact with DFTs.Males of both species were sensitive to variations in concentration of extract, and spent 2–6 times longer in contact with DFTs when the concentration was optimal than when it was not. No significant difference in the male's mating response was seen in response to variation in concentration of heterospecific extract.Male mating response, i.e. the behaviour of the male as it progresses through the initial contact, climbing onto the dorsal surface and turning onto the venter, was shown not to be dependent upon how long the male spent in contact with the DFT. Male D. andersoni had a much lower mating response to DFTs than D. variabilis males, suggesting that some further stimulus may be required.
Malaria infection potential of anopheline mosquitoes sampled by light trapping indoors in coastal Tanzanian villages
Authors: SHIFF C. J. , MINJAS J. N. , HALL T. , HUNT R. H. , LYIMO S. , DAVIS J. R. 
Published: March 2008

Abstract. Anopheline mosquito populations were studied during 1992 in seven villages south of Bagamoyo, coastal Tanzania, prior to malaria control intervention using insecticide treated bednets. To collect mosquitoes, CDC light traps were used in ten houses per village fortnightly for 12 months. Anopheles females were identified and checked by ELISA for the presence of malaria sporozoite antigen and source of bloodmeal. An. funestus peaked in June‐July after the long rains. Three members of the An. gambiae complex had different seasonality: An. arabiensis, An. gambiae and small numbers of An. merus were collected.In most villages transmission was extremely high and perennial with the entomological inoculation rate reaching three to eleven infective bites per person per night in July and persisting at around 0.1 and 1 for most of the remainder of the year. Sporozoite infection rates within the An. gambiae complex ranged from 2% to 25%, with the peaks in January and July following the two rainy periods. An. funestus showed a similar pattern. The light traps were reliable, simple to operate, and proved to be satisfactory to study the mosquito vector population.
Mosquito control in Dar es Salaam.
Authors: CHAVASSE C. , LINES J. D. , ICHIMORI K. , MARIJANI J. 
Published: March 2008

Abstract. In preparation for a trial of polystyrene beads and pyriproxyfen for the control of Culex quinquefasciatus mosquitoes, surveys of their breeding were carried out in two contrasting areas of Dar es Salaam, Mikocheni and Ilala, during the dry season.Sanitation structures (latrines, soakage pits, septic tanks and cess pits) were the most prolific breeding places, totalling 780 in Mikocheni and 1544 in Ilala. Those in Mikocheni were estimated to contain about 1.4 times more mosquito pupae, per site, than in such structures in Ilala. This was both because a higher proportion of sites contained visible water and because sites with water were more likely to contain pupae in Mikocheni. The relative importance of the different types of structure, in terms of productivity, was the same in both areas. Although septic tanks and cess pits made up only 10.5% of the on‐site sanitation structures in Ilala, they contained 53% of the total number of pupae in enclosed sites; they were therefore particularly important targets for treatment with polystyrene beads. A survey during the rainy season of sites in Ilala revealed little change in the proportion that were wet, or in the frequency of breeding in those with visible water.The number, type and area of open breeding sites varied greatly between the two study areas. In Mikocheni the area of open breeding sites was 100 times greater than in Ilala, with 97% of the13,000 m2 being flooded grassland. In Ilala all but four of the sixty‐six open breeding sites were puddles of sullage water derived from bathrooms. Different strategies for control in open breeding sites are required in the two areas of Dar es Salaam.
An assessment of host resistance to ticks on cross‐bred cattle in Burundi
Authors: MORAN M.C. , NIGARURA G. , PEGRAM R.G. 
Published: March 2008

Abstract. Groups of cattle of four different cross‐breeds (Ankole × Friesian, Ankole × Brown‐Swiss, Ankole × Guernsey, Ankole × Sahiwal) plus a group of pure Ankole cattle were immunized against tick‐borne diseases: East Coast Fever, using a Theileria parva trivalent vaccine, and anaplasmosis, babesiosis and, subsequently, heartwater. With the exception of two small subgroups of Ankole and Ankole	× Sahiwal which were treated by weekly spraying using Delnav, all the groups were exposed to natural field challenge of ticks to quantify the development of host resistance to ticks. The results indicate resistance to the most abundant species, Rhipicephalus appendiculatus, as follows: Ankole > Ankole × Sahiwal > Ankole × Brown Swiss > Ankole × Friesian > Ankole × Guernsey. In both Amblyomma variegatum and Rhipicephalus evertsi evertsi, the manifestation of different levels of resistance between breeds is inapparent. Correlations between total ticks and standard female ticks were good for R. appendiculatus (r = 0.73) and R. evertsi (r ‐ 0.51) but poor for A. variegatum (r= 0.31). Correlations between species were reasonably consistent (r = 0.43‐0.59). There was no significant correlation between tick burdens and daily liveweight gain (DLWG) over the. whole period of the study. Of the cross‐bred groups, Ankole × Sahiwal, which had the highest level of resistance, had the highest DLWG. In contrast, the Ankole × Guernsey which developed the lowest level of resistance had only marginally lower DLWG, the difference being only 8 g/day. During the first period of exposure to ticks, however, the untreated Ankole × Sahiwal group had markedly lower DLWG, which may indicate that the development and manifestation of resistance is at the expense of productivity.
Anthropophilic blackflies (Diptera: Simuliidae) and onchocerciasis transmission in southwest Ethiopia
Authors: GEBRE‐MICHAEL T. , GEMETCHU T. 
Published: March 2008

Abstract. From May 1984 to May 1985, the transmission of onchocerciasis by blackflies (Dipteria: Simuliidae) was studied around Gilgel Ghibe and Gojeb rivers in southwest Ethiopia. The predominant anthropophilic species of Simulium at both localities were S.(Edwardsellum) damnosum sensu law and S.(Lewisellum) ethiopiense. Some S.(Anasolen) dentulosum also landed on human bait at Gilgel Ghibe river.Dissections of S. damnosum from Gilgel Ghibe and Gojeb revealed mean parous rates of 92% (n = 18,291) and 84%(n = 9530), respectively. S. ethiopiense from Gilgel Ghibe and Gojeb showed mean parous rates of 53% (n = 322) and 93% (n = 14), respectively. Of the parous S. damnosum, 1.3% at Gilgel Ghibe and 0.5% at Gojeb harboured infective third‐stage larvae (L3) of Onchocerca volvulus (or morphologically indistinguishable from it). Unknown filariae of animal origin, indicative of zoophily, were found in 0.3% and 0.7% of Simulium damnosum complex females from Gilgel Ghibe and Gojeb, respectively. S. ethiopiense harboured developing (L,) larvae only, with 7.7% infection rate in both localities. In contrast, S. dentulosum did not harbour any filaria larvae. The annual infective biting rate (AIBR) and transmission potential (ATP) of the S. damnosum complex at Gilgel Ghibe river were 858 and 5478, respectively. The AIBR and ATP of S. damnosum s.I. at Gojeb river were 519.5 and 1963, respectively. These results emphasize the predominant role of the S. damnosum complex in the transmission of O. volvulus in southwest Ethiopia
Surveillance of the mosquito Aedes aegypti and its biocontrol with the copepod Mesocyclops aspericornis in Australian wells and gold mines
Authors: RUSSELL B. M. , MUIR L. E. , WEINSTEIN P. , KAY B. H. 
Published: March 2008

Abstract. A survey of the dengue vector mosquito Aedes aegypti was undertaken using runnel traps to detect immature stages (larvae and pupae) in flooded disused mine shafts and wells in Charters Towers, Queensland, Northern Australia. The town has a history of dengue fever since 1885 when goldminers were the first recorded victims. During the latest dengue epidemic in 1993, 2% of the population had laboratory‐confirmed dengue virus Type 2, despite source reduction of Ae.aegypti breeding‐sites at ground level or above. This led to suspicions that dengue vector Ae.aegypti breeding‐sites might be below ground level. When surveyed in March 1994, Ae.aegypti immatures were found in 9/10 wells and 1/6 mine shafts. The water in wells and mines had similar characteristics ‐except that turbidity was higher in the mines, which more often contained predators of mosquito immatures.The copepod Mesocyclops aspericornis was collected from water in 1/10 wells and 2/6 mine shafts. Laboratory predation trials resulted in 95.5–100% predation by 25 copepods/1 on Ae.aegypti first‐instar larvae up to 200 larvae/1. Five wells containing Ae.aegypti in the survey were inoculated with fifty indigenous M.aspericornis, and five wells (one positive and four negative in the survey) were left untreated as controls. Nine months later, in December 1994, Ae.aegypti had been eliminated from all five treated wells but all untreated control wells contained Ae.aegypti, except for one well that contained a natural population of M.aspericornis. The role of wells and mines as winter/ dry season refuges of Ae.aegypti in northern Australia is reviewed, and we recommend the use of M.aspericornis as a cost‐effective, environmentally acceptable and persistent agent for the sustainable control of Ae.aegypti, especially in inaccessible breeding sites.
The impact of permethrin‐impregnated bednets on malaria vectors of the Kenyan coast
Authors: MBOGO C. N. M. , BAYA N. M. , OFULLA A. V. O. , GITHURE J. I. , SNOW R. W. 
Published: March 2008

Abstract. The effects of introducing permethrin‐impregnated bednets on local populations of the malaria vector mosquitoes Anopheles funestus and the An.gambiae complex was monitored during a randomized controlled trial at Kilifi on the Kenyan coast. Pyrethrum spray collections inside 762 households were conducted between May 1994 and April 1995 after the introduction of bednets in half of the study area. All‐night human bait collections were performed in two zones (one control and one intervention) for two nights each month during the same period. PCR identifications of An.gambiae sensu lato showed that proportions of sibling species were An.gambiae sensu stricto > An.merus > An.arabiensis.Indoor‐resting densities of An.gambiae s.l. and the proportion of engorged females decreased significantly in intervention zones as compared to control zones. However, the human blood index and Plasmodium falciparum sporozoite rate remained unaffected. Also vector parous rates were unaltered by the intervention, implying that survival rates of malaria vectors were not affected. The human‐biting density of An.gambiae s.l., the predominant vector, was consistently higher in the intervention zone compared to the control zone, but showed 8% reduction compared to pre‐intervention biting rates ‐ versus 94% increase in the control zone.Bioassay, susceptibility and high‐performance liquid chromatography results all indicated that the permethrin content applied to the nets was sufficient to maintain high mortality of susceptible vectors throughout the trial. Increased rates of early outdoor‐biting, as opposed to indoor‐biting later during the night, were behavioural or vector composition changes associated with this intervention, which would require further monitoring during control programmes employing insecticide‐treated bednets.
Identification of electrophysiologically‐active compounds for the malaria mosquito, Anopheles gambiae, in human sweat extracts
Authors: CORK A. , PARK K. C. 
Published: March 2008

Abstract. Human sweat samples were chemically fractionated into acid and non‐acid components. The most abundant volatile compounds present in the fractions were identified by linked gas chromatography mass spectrometry. The acid fractions were found to be composed of a range of twenty aliphatic and three aromatic carboxylic acids ranging, on average, from 0.02 to 20 ig per ml of sweat sampled. Non‐acid fractions were found to contain: 6‐methyl‐5‐hepten‐2‐one, l‐octen‐3‐ol, decanal, benzyl alcohol, dimethylsulphone, phenylethanol, phenol and 4‐mefhylphenol, collectively amounting to 0.1 and 3 |ig per ml of sweat. The major component of sweat was found to be L‐lactic acid which constituted from 1 to 5 mg/ml.Using the intact antennae of the anthropophilic malaria vector mosquito Anopheles gambiae Giles, the peripheral olfactory activities of compounds identified in the sweat fractions were investigated by electroantennography (EAG). Short‐chain saturated carboxylic acids, methanoic, ethanoic, propanoic, butanoic, pentanoic and hexanoic acids were found to elicit significantly larger EAG responses than longer chain saturated carboxylic acids from female An.gambiae. For a given dose the largest amplitude EAG response was elicited by methanoic acid. Pentanoic acid elicited larger EAG responses than either butanoic or hexanoic acids. Two non‐acidic compounds, l‐octen‐3‐ol and 4‐methylphenol, were found to elicit significant dose‐dependent EAG responses from female An.gambiae. 1 ‐Octen‐3‐ol elicited larger EAG responses than 4‐methylphenol for a given dose, but both compounds elicited smaller EAG responses than the same dose of C]‐C6straight‐chain aliphatic carboxylic acids. The possible behavioural significance of the EAG‐active compounds identified in human sweat samples is discussed.
Differential application of lambda‐cyhalothrin to control the sandfly Lutzomyia longipalpis
Authors: KELLY DAVID W. , MUSTAFA ZEHRA , DYE CHRISTOPHER 
Published: March 2008

Abstract. To study the impact of residual pyrethroid insecticide on the abundance and distribution of peridomestic Lutzomyia longipalpis, the sandfly vector of visceral leishmaniasis in Brazil, lambda‐cyhalothrin was applied at 20 mg a.i.m‐2 in the following interventions: (i) spraying of all animal pens in a village (blanket coverage); (ii) treatment of a subset of animal pens, either by spraying, or by installation of insecticide‐impregnated 1 m2 cotton sheets as ‘targets’ (focal coverage).By sampling with CDC light traps, and using a novel analytical approach, we detected a 90% reduction in Lu. longipalpis abundance in sprayed sheds of the focal intervention. However, there was no discernible effect on the abundance of other phlebotomines trapped in sheds, or on the abundance of Lu. longipalpis in untreated dining‐huts and houses. This differential impact on Ludongipalpis abundance is explained in terms of the disruption of male pheromone production. Treated targets were approximately half as effective as residual spraying in reducing the abundance of Lu.longipalpis in sheds.Following blanket intervention, the abundance of Lu.longipalpis in traps fell by only 45% (not significant): catches at untreated dining‐huts actually increased, possibly because the blanket coverage diverted Lu. longipalpis away from major aggregation sites at animal pens. It is recommended that care be taken during vector control programmes to ensure that all potential aggregation sites are treated. The possible consequences of leaving some sites untreated include poor control of peridomestic sandfly abundance and an increase in the biting rate on dogs and humans.
Effect of the life‐span of female Glossina palpalis gambiensis on the weight and size of its progeny
Authors: DEKEN R. DE , BOSSCHE P. VAN DEN , SANGARE M. , GNANVI C. , MISSANDA J. H. , HEES J. VAN 
Published: March 2008

Abstract. Pupae and teneral flies of Glossina palpalis gambiensis originating from three successive reproductive cycles were compared for their size and weight. In general, pupal weight and fly weight increased, whereas fly size, measured as wing vein length, decreased with the number of reproductive cycles. The linear regression observed between weight and wing vein length of the fly demonstrated that, particularly for flies originating from the first and second larvipositions, small changes in wing vein length reflected substantial differences in weight.The results of these laboratory experiments were compared with some field data on Glossina morsitans from Zambia and related literature. The life span of the female tsetse, affecting the size of her progeny, could clarify partially some of the field observed seasonal changes in size, whereas the correlation between fly size and weight could eventually explain the differential mortality of some size classes of tsetse flies. However, whether these laboratory observations can be extrapolated to the field has still to be confirmed.
The effects of the bont tick, Amblyomma hebraeum, on milk production of Sanga and Sanga x Brahman cattle
Authors: NORVAL R. A. I. , SUTHERST R. W. , JORGENSEN O. G. , KERR J. D. 
Published: March 2008

Abstract. The effects of adults of the bont tick, Amblyomma hebraeum on the milk production of Sanga and Sanga x zebu (Brahman) cattle were measured over a period of 11 weeks in the lowveld of Zimbabwe in the summer of 1986. Four groups of lactating cows, consisting of two breeds, each divided into a high and low tick treatment, were exposed to very low or high challenges of ticks and their milk production measured by weighing their calves before and after suckling. The liveweight gains (LWG) of the calves were also measured.Tick burdens on the infested groups averaged around fourteen engorging females of A.hebraeum per day, which amounted to infestations of about 150 adult ticks. That is greater than most observed field infestations. This caused no significant reduction in milk yield or calf growth over the whole period, provided the teats of the dams had not been damaged by ticks. Mismothering occurred when teats were damaged. No breed differences were observed so all data was pooled for further analysis. Average calf LWGs of the high tick groups were reduced by 2.2kg (P < 0.01) during one 4‐week period but overall the 3.9 kg difference in LWG of the tick treatment groups was not quite significant (P < 0.10). Although there was a poor relationship between tick numbers and reduced milk yield or calf LWG, the effects were always in the direction expected. The effects averaged 6 ± lOg reduction of milk and 2.6 ± 1.8g loss of LWG of calves for every female tick that engorged. It was concluded that milk production is not an important consideration when estimating the losses in production caused by A.hebraeum on Brahman x Sanga or Sanga breeds of cattle. Losses due to teat or udder damage could be much more important and need to be quantified.