摘要:

Abstract.The incidence of dengue haemorrhagic fever (DHF) in Thailand has increased cyclically since the first recognized outbreak in 1958. Without an effective vaccine against dengue, and considering the clinical difficulty of treating DHF cases, vector control is needed to prevent dengue transmission. Since the establishment of the WHO Aedes Research Unit in 1964, continued since 1973 as the WHO Collaborating Centre at the Department of Medical Research in Bangkok, much operational research has been carried out in Thailand on the bionomics and control of dengue vectors:Aedes aegyptiandAe.albopictus.This review shows that, as in most other countries, dengue vector control programmes in Thailand make little use of the procedures arising from research, nor have they reduced the upward trend of dengue or prevented DHF outbreaks. Implications of the reluctance to use results of operational research on vector control are considered and remedial suggestions made.

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1993.tb00644.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.The enzymes acetylcholinesterase, glutathione S‐transferase (GST), glucose 6‐phosphate dehydrogenase (G6PD), and general esterases were assayed in four strains ofAedes aegyptimosquitoes aged between 1 and 30 days. Microtitre plate methods were used to assay activity in the homogenates of individual mosquitoes. The levels of GST and G6PD declined with the age of the mosquitoes, while the activity for the other enzymes remained constant. Soluble protein content was also found to decline with mosquito age in all the strains.Insecticide bioassays showed that two strains (Trinidad and Virtudes) ofAe. aegyptiwere resistant to DDT, deltamethrin and malathion, whereas two other strains (Bangkok and Indian) were susceptible to all four classes of insecticides tested.Higher esterase activity levels in the resistant compared to the susceptible strains were assumed to be the cause of organophosphate resistance. The combination of DDT and deltamethrin resistance in two strains with normal GST and G6PD characteristics suggests that a kdr‐type nerve insensitivity mechanism may be inv

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1993.tb00645.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.The density of cattle‐visiting flies (Muscidae) and the load of black‐flies(Simuliumspp.) were estimated in twelve and eighteen inland pastures in Denmark in 1984 and 1985 respectively. No differences in the geographical distribution pattern of the predominant cattle‐visiting Muscidae were recorded, whilst the relative abundance and density of the species and the total fly‐load varied considerably between pastures. In most cases the mean loads ofHaema‐tobia irritans(L.) andHydrotaea irritans(Fall.) on heifers varied significantly in relation to site topography and shelter. These crude site variables explained 65–98% of the variation in densities of horn flies and sheep head flies observed between pastures. Highest densities ofHydrotaea irritanswere primarily associated with permanent, low‐lying, fairly sheltered grassland sites, whereas the density was low in temporary, dry, wind‐exposed pastures. A comparable relationship was found forHaematobia irritans.WithHaematobosca stimulans(Mg.) andMorelliaspp. no relation between grassland environment and fly densi

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1993.tb00646.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.Data onCulicoides imicolawere obtained during studies carried out during the recent outbreak of African horse sickness in Portugal. The previous most northerly published record ofC.imicolain Portugal was 38o40'N (Pégöes). In the present work the geographical distribution of this species is extended to the parallel of 41o17'N. We have also confirmed the continuous presence of adultC.imicolain Southern Portugal (Alentejo and Algarve) throughout the year. In the laboratory we obtained this species from a sample of cattle faeces and from another of soil contaminated with animal excreta. In relation to host association 57.37% ofC.imicolawere trapped in the vicinity of pigsties. Finally, we collected11,463Culicoidesof which 12.47% wereC. imicol

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1993.tb00647.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.In preparation for a Filariasis Control programme in Samoa, during 1978 monthly larval surveys of the vector mosquitoAedes polynesiensiswere carried out in four study villages in the main island of Upolu. A more extensive survey of larval habitat distribution was then made in twenty‐two villages of Upolu and eighteen of Savai'i island, to determine the importance of habitat types according to their abundance, volume of water and whether their productivity was permanent or seasonal.Ae.aegyptilarval densities and habitat distribution were also monitored and the occurrence of predatoryToxorhynchites amboinensislarvae in northern Upolu was recorded from forty‐one collections.AedesBreteau and container indices fluctuated with the pattern of rainfall in two coastal villages and an inland bush village, but not in a coconut plantation community. The five mainAedeslarval habitat types encountered were: 200 litre water‐storage drums, discarded tins and bottles, coconut shells, automobile tyres and treeholes.Aedesimmatures occurred perennially in drums and tree holes, but breeding discontinued in tins, bottles and coconut shells during the driest month of July.ForAe.polynesiensisin Upolu the Breteau and container indices of 104.5 ± SD 80.9 and 35.3 ± 12.4 respectively were significantly higher than those in Savai'i: 33.1 ±25.0 and 24.3 ±20.0 respectively. Likewise forAe.aegyptithe Breteau and container indices of 50.8 ± 32.5 and 23.9 ± 15.6, respectively, were also significantly higher than those in Savai'i: 12.7 ± 17.1 and 9.4 ±13.2 respectively.Habitat types greater or lesser importance were determined by plotting the percentage of each type of container utilized forAedesbreeding against the percentage of each type amongst all larva‐positive containers.Ae.polynesiensispreferred tree‐holes but not water‐storage drums.Ae.aegyptipreferred drums and tyres; mixed populations of larvae of both species were commonest in these two types of habitat.Ae.polynesiensisoccurred in every village.Ae.aegyptiwas encountered in all twenty‐two villages surveyed in Upolu and nine of eighteen villages in Savai'i.Total larval surveys revealed that drums and tree‐holes contained the highest numbers ofAedeslarvae. The study provided criteria for plann

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1993.tb00648.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.Among samples collected from nineteen localities in Papua New Guinea, we have identified six species within theAnopheles punctulatuscomplex of mosquitoes, by means of cellulose acetate allozyme electrophoresis.An.punctulatusDönitzsensu strictowas collected from seven villages in the Madang area and from Buksak, Sausi Mission and an area 18 km SW of Tari;An.koliensisOwen from eight villages in the Madang area, from Popondetta and Brown River near Karema; andAn.farautiNo. 1 from ten coastal areas including Madang, Lorengau, Popondetta, Port Moresby, Rabaul and Wewak. Three newly recognized species, reported here for the first time, are designated asAn.farautiNo. 4 from Gonoa and Hudini, Madang area;An.farautiNo. 5 from Ketarabo near Goroka; andAn.farautiNo. 6 from Hiwanda near Tari. Three other known members of the complex,An.clowiRozeboom&Knight,An.farautiNo. 2 (Bryan, 1973) andAn.farautiNo. 3 (Mahon&Meithke, 1982) were not detected in Papua New Guinea. Problems arising with morphological characters for the identification of species in this group are discussed

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1993.tb00649.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.Electrophoretic keys are given for the six species of theAnopheles punctulatuscomplex (Diptera: Culicidae) known from Papua New Guinea plusAn.farautiNo. 2 and No. 3 from Australia. The categories ‘faster’, ‘standard’ and ‘slower’ are used in keys to relate allozyme band migration following cellulose acetate electrophoresis to the standard pattern. Alternative keys are given depending on the availability of different species for use a

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1993.tb00650.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.The gerbil fleaNosopsyllus laeviceps(Wagner) (Siphonaptera: Ceratophyllidae) is an important Palaearctic vector of enzootic plague among sylvan and campestral rodents. Laboratory blood‐feeding experiments with the subspeciesN.l.kuzenkovi(Yagubynts) from Inner Mongolia, China, using three rodent species including the natural hostMeriones unguiculatus(Milne‐Edwards), demonstrated a positive relationship between per cent feeding and time allowed for feeding, particularly for female fleas. Also the bloodmeal size was proportional to sucking time and was significantly greater in females, which are larger, than in males. However, on all four strains of host tested, there was no significant correlation between the feeding success rate of the fleas and the amount of blood they imbibed. Fleas fed better on active compared to confinedM.unguiculatus. These findings agree with studies of other flea spec

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1993.tb00651.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.A field study in Libya investigated aspects ofCochliomyia hominivoraxbehaviour relevant to the operation of a target‐based control system. Flies were readily caught by electrified targets, but only when baited with the attractant ‘swormlure‐4’. Target size (0.25‐lm2) did not affect catch, but black targets caught twice as many flies as red ones. Omitting the most volatile component of swormlure‐4, dimethyl disulphide, significantly reduced catches of both sexes ofC. hominivoraxin wind‐orientated traps, but only reduced the capture of females significantly on targets. A new polythene sachet dispenser for odours was tested; four to six such sachets filled with swormlure‐4 less dimethyl disulphide gave an equivalent catch to one of the standard bottle plus wick dispensers using the same attractant, although they dispensed odour at about half the rate.From direct observations, fewer than 40% of flies contacted the target for more than 10 s on any one visit. From catches on an intermittently‐active electrocuting grid, it was calculated that there is ac. 40% rate of multiple contacts of flie

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1993.tb00652.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.High titres of antibodies to antigens derived from head/thorax, midgut or abdomen ofAnopheles tessellatuswere produced in inbred mice. These antibodies, when ingested in a bloodmeal, reduced the fecundity ofAn.tessellatusby up to 29% in different experiments. It is postulated that antibodies directed against antigens shared between the head/thorax, abdomen and midgut tissues are involved in the reduction of fecundity.

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1993.tb00653.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY