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The accumulation of plastics in our environment has generated serious eco-environmental problems and the need to look for alternatives for the production of bioplastic. The purpose of this work was to evaluate the effect of the proportion of fibers from vegetable leaves (banana and achira) with oca starch on the physical and mechanical properties of biodegradable trays made through the thermoforming process. 3 percentages (2.5%, 5% and 7.5%) of natural fiber with a size between 53 - 75 µm were used. The formulated trays were evaluated by their physical properties (color, thickness, density, humidity and water absorption), mechanical (resistance to tension, elongation and perforation) and Fourier transform infrared spectroscopy (FT-IR).). The results showed trays with adequate expansion, homogeneously distributed fibers and acceptable appearance. As the fiber concentration increased, the ability to absorb water increased, however, the moisture content, puncture resistance and fracturing decreased. In general, the tray with 2.5% banana leaf fiber obtained the best results. These trays can be used to pack dry food with a short shelf life and can be a viable alternative to replace polystyrene trays.

We present a case of catatonia, which occurred shortly after starting a new antipsychotic, paliperidone, an active metabolite of risperidone. Catatonia may be caused by a variety of conditions, including metabolic, neurologic, psychiatric and toxic processes. Interestingly, risperidone, which has been thought to cause several cases of catatonia, has also been recommended as a potential treatment. We discuss potential mechanisms for causes of drug-induced catatonia as well as potential treatment options.

The Australasian Annulipes Complex is the most species-rich among Anopheles mosquitoes, with at least 15 sibling species suspected. Members of this complex are the most likely vectors of malaria in the past in southern Australia and are involved in the spread of myxomatosis among rabbits. In this, the first comprehensive molecular study of the Annulipes Complex, 23 ITS2 rDNA variants were detected from collections throughout Australia and Papua New Guinea, including diagnostic variants for the previously identified An. annulipes species A-G. Specimens of each ITS2 variant were sequenced for portions of the mitochondrial COI, COII and nuclear EF-1alpha genes. Partitioned Bayesian and Maximum Parsimony analyses confirmed the monophyly of the Annulipes Complex and revealed at least 17 clades that we designate species A-Q. These species belong to two major clades, one in the north and one mainly in the south, suggesting that climate was a driver of species radiation. We found that 65% (11) of the 17 sibling species recorded here had unique COI sequences, suggesting that DNA barcoding will be useful for diagnosing species within the Annulipes Complex. A comparison of the taxa revealed morphological characters that may be diagnostic for some species. Our results substantially increase the size of the subgenus Cellia in Australasia, and will assist species-level studies of the Annulipes Complex.

The health belief model (HBM) has been adopted as the principal theory for health education and communication for dengue haemorrhagic fever (DHF) prevention and control in Thailand. The HBM focuses on persuading people to acknowledge their vulnerability and susceptibility to DHF, and the benefits of undertaking dengue larval control in household water containers. This study was undertaken in Khon Kaen province to investigate folk knowledge and beliefs about dengue mosquitoes and larval control campaigns and relating these to the theoretical components of HBM. Findings from this study indicate that health education messages can raise awareness during an outbreak but do not ensure sustained larval control practices. Several barriers are identified, including insufficient control agents, inadequate knowledge of control methods, and incompatibility of control practices with people's beliefs. The barriers prevail over the benefits of recommended larval control practices. In developing health education messages, consideration should go beyond the HBM and focus on control methods that are compatible with the socio-cultural environment in which control practices are being encouraged.

Allozyme and molecular sequence data from the malaria vector Anopheles flavirostris (Ludlow) (Diptera: Culicidae) were analysed from 34 sites throughout the Philippines, including the type locality, to test the hypothesis that this taxon is a single panmictic species. A finer-scaled allozyme study, of mainly Luzon samples, revealed no fixed genetic differences in sympatric sites and only low levels of variation. We obtained data from partial sequences for the internal transcribed spacer 2 (ITS2) (483 bp), the third domain (D3) (330 bp) of the 28S ribosomal DNA subunit and cytochrome c oxidase subunit I (COI) of mitochondrial DNA (261 bp). No sequence variation was observed for ITS2, only a one base pair difference was observed between Philippine and Indonesian D3 sequences and An. flavirostris sequences were unique, confirming their diagnostic value for this taxon. Sixteen COI haplotypes were identified, giving 25 parsimony informative sites. Neighbour-Joining, Maximum Parsimony, Maximum Likelihood and Bayesian phylogenetic analysis of COI sequences for An. flavirostris and outgroup taxa revealed strong branch support for the monophyly of An. flavirostris, thus confirming that Philippine populations of this taxon comprise a single separate species within the Minimus Subgroup of the Funestus Group. Variation in the behaviour of An. flavirostris is likely to be intraspecific rather than interspecific in origin.

Objective: To investigate the influence of larval control methods (using temephos, keeping fish and covering containers with lids), water use and weekly cleaning of containers on the presence of Aedes aegypti larvae in water-storage containers in rural and urban households in Khon Kaen province., Method: Cross-sectional questionnaire survey and larval survey covered 966 households and 5821 containers were inspected., Result: In rural and urban areas larval control was patchy and often ineffective. Consequently, the mosquito indices exceed the target indices for dengue control with the Breteau Indices of 201 and 113, and Container Indices of 25 and 28 in rural and urban areas, respectively. The containers most frequently infested with larvae were rectangular cement containers storing water for bathing (rural: 37.2%; urban: 35%) and flushing the toilets (rural: 35.7%; urban: 34.3%). Keeping fish [adjusted odds ratio (AOR): 0.08-0.16] was the most effective methods of control. Correctly covering containers with lids was similarly effective (AOR: 0.10-0.25) when used on jars for storing drinking water. However, frequent use of containers reduced the effectiveness of lids. Temephos was effective only in dragon jars in urban areas (AOR: 0.46) where a standard package of temephos were available. Weekly cleaning of containers was an effective method for larval control in most types of containers. A combination of control methods increased effectiveness., Conclusion: This study highlights the complex interaction of household water use and larval control practices as well as the importance of determining the most effective control measures compatible with water practices for implementing control promotion.

Ochlerotatus notoscriptus (Skuse) (Diptera: Culicidae) is the predominant peridomestic mosquito in Australia where it is the primary vector of dog heartworm, Dirofilaria immitis (Leidy), and a potentially important vector of arboviruses (Barmah Forest, Ross River) with geographical variation of vector competence. Although widespread, Oc. notoscriptus has low dispersal ability, so it may have isolated subpopulations. The identification of gene flow barriers may assist in understanding arbovirus epidemiology and disease risk, and for developing control strategies for this species. We investigated the population structure of Oc. notoscriptus from 17 sites around Australia, using up to 31 putative allozyme loci, 11 of which were polymorphic. We investigated the effect of larval environment and adult morphology on genetic variation. At least five subpopulations were found, four in New South Wales (NSW) and one unique to Darwin. Perth samples appear to be a product of recent colonization from the Australian east coast. For NSW sites, a Mantel test revealed an isolation by distance effect and spatial autocorrelation analysis revealed an area of effective gene flow of 67 km, which is high given the limited dispersal ability of this species. No consistent difference was observed between 'urban' and 'sylvan' habitats, which suggests frequent movement between these sites. However, a finer-scaled habitat study at Darwin revealed small but significant allele frequency differences, including for Gpi. No fixed allozyme differences were detected for sex, size, integument colour or the colour of species-diagnostic pale scales on the scutum. The domestic habit of Oc. notoscriptus and assisted dispersal have helped to homogenize this species geographically but population structure is still detectable on several levels associated with geographical variation of vector competence.

A description of Anopheles (Cellia) irenicus Schmidt, sp.n. (formerly A. farauti No. 7) is provided. This species is one of six recorded from the Solomon Islands within the A. punctulatus group, which contains the major vectors of the causative agents of malaria and lymphatic filariasis in the southwest Pacific. Morphological markers are described for adult females, fourth-instar larvae and pupae that identify most specimens of A. irenicus. Keys are presented to distinguish members of the A. punctulatus group in the Solomon Islands.

Malaria control strategies are more likely to be successful if groups at high risk can be accurately predicted. Given that mosquitoes have an obligate aquatic phase we were interested in determining how vector larval abundance relates to the spatial distribution of human malaria infection. We examined the relationship between malaria parasite prevalence and distance from vector larval habitat, and vector larval abundance and distance from human habitation, in separate studies in rural, low-endemic areas of the Philippines. Parasite prevalence among symptomatic patients was significantly higher among those living in proximity (< or = 50 m) to potential larval habitats of the major vector, Anopheles flavirostris (adjusted odds ratio [AOR] = 2.64, P = 0.02 and AOR = 3.43, P = 0.04). A larval survey of A. flavirostris revealed a higher density of early and late instars near human habitation (adjusted P < 0.05). The results suggest that larvae are associated with human habitation, thereby reinforcing malaria risk in people living close to larval habitats. This has implications for understanding the interaction between vectors, hosts, and parasites, and the potential for success of localized malaria control measures.

Descriptions of the three sibling species of the Anopheles farauti complex in Australia, A. farauti Laveran (formerly A. farauti No. 1), A. hinesorum Schmidt sp.n. (formerly A. farauti No. 2) and A. torresiensis Schmidt sp.n. (formerly A. farauti No. 3) are provided. These species form a part of the punctulatus group, which contains the major malaria vectors in the southwest Pacific. Morphological markers are described for adult females, fourth instar larvae and pupae which identify most specimens, and are presented in keys.

We surveyed the larval habitats of members of the Anopheles punctulatus group of mosquitoes on Niolam (Lihir) Island, Papua New Guinea. Identification of this group was undertaken by polymerase chain reaction-restriction fragment length polymorphism analysis of the amplified internal transcribed spacer unit 2 of rDNA, because morphologic separation of member species is unreliable. The most widespread malaria vector species and their most common larval habitats were identified to aid source-reduction programs for malaria control. The most ubiquitous species was An. punctulatus, followed by An. farauti no. 2. then An. farauti s.s. Anopheles punctulatus has increased relative to An. farauti s.l. since the start of development projects on Lihir Island. The most common larval habitats were shallow temporary pools with clay substrate and with plants or floatage. These habitats, mostly encountered alongside poorly drained roads, may be increased by development projects.

Among the Punctulatus Group of Anopheles mosquitoes (Diptera: Culicidae), first-instar larvae of the medically unimportant freshwater Anopheles farauti species No. 7 survives a seawater tolerance test (STT) that was previously thought to be diagnostic for the saltwater-tolerant malaria vector species, An. farauti Laveran s.s. Salt tolerance in these two closely related isomorphic species appears to be a shared derived character within the Farauti Complex. Failure to differentiate An. farauti s.s. from An. farauti No.7 will overestimate potential malaria vector numbers and waste limited larval control resources. Use of the STT should therefore be discontinued on Guadalcanal and other techniques such as allozyme electrophoresis used instead [corrected].

We investigated mortality in Anopheles farauti mosquitoes, a major coastal malaria vector in the south-west Pacific, fed on a volunteer who had taken a 250 micrograms/kg dose of ivermectin. High mortality was recorded in mosquitoes feeding during the first week after treatment of the volunteer, for instance 100-80% failed to survive 3 days. A long-term residual effect of ivermectin in the blood was indicated by a small but significantly higher mortality in mosquitoes fed 6 weeks after ivermectin was taken. These effects were included in malaria transmission models that incorporated host choice and host-induced mortality parameters. For the zoophilic An. farauti, ivermectin treatment of animals resulted in a greater reduction in malaria than ivermectin treatment of humans alone, whereas for an anthropophilic vector, treatment of humans was more important. This suggests that ivermectin treatment of animals could have an important role in malaria control where An. farauti is the vector. Improvement in the health of humans and domestic animals through control of parasitic worms and mites might encourage community participation in strategies involving ivermectin.

Anopheles kochi is reported for the 1st time from New Guinea, probably introduced by aircraft. This Oriental species was originally detected by analysis of polymerase chain reaction-amplified rDNA internal transcribed spacer unit 2 (ITS-2). Identification was confirmed by morphologic examination. Size of ITS-2 is presented for 32 species of Australasian and Oriental anophelines to assist morphologic identifications for distribution and vector studies.

Government health policy for malaria control in Solomon Islands has three main objectives: (1) early diagnosis and treatment of malaria at a health service; (2) reduction of human-vector contact through widespread use of insecticide-impregnated bed nets; and (3) provision of malaria chemoprophylaxis for pregnant women. Social research was carried out in thirteen villages in central Malaita to determine local attitudes toward malaria and to estimate the level of participation in malaria control activities. Interviews with 124 care-givers who had children 0-10 years of age, 20 focus group discussions and four evening structured observations were research methods used. Antimalarial drugs were the most favoured treatment, and use of traditional medicines and healers were reportedly minimal. Twenty-five percent of respondents reported keeping chloroquine at home and 42% said they would use chloroquine before seeking diagnosis and treatment from a health service. Structured observations suggest that protection against mosquitoes is poor during the evening. Fifty-two percent of respondents reported using fire and 32% said they used bed nets to protect themselves from mosquitoes. Participants had contradictory beliefs on the threat of malaria during pregnancy and the safety of taking chloroquine prophylaxis. Implications of malaria treatment and prevention practices are discussed, and recommendations for improving malaria control are presented.

The present study investigated the use of insecticide-impregnated bed nets by communities in central Malaita, Solomon Islands. Qualitative and quantitative data were collected by: (1) questionnaire administration to 124 care-givers of children aged 0-10 years of age; (2) 20 focus group discussions; (3) two structured observations of bed net re-impregnation, and (4) interviews with key informants. Ninety-four percent of all care-givers had bed nets, but only 62% had sufficient bed nets for all household members. Fifty-two percent used bed nets throughout the year and 70% of care-givers reported that all their children slept under bed nets. Although coastal householders considered malaria and mosquitoes more of a problem than inland householders, overall bed net compliance did not differ. Factors affecting bed net ownership were cost and community expectation of free bed nets. Bed net use was affected by four factors: (1) seasonality (99% used bed nets during the rainy season, 52% used them all year); (2) mosquito nuisance (59% of respondents reported that protection against mosquitoes was the main reason for using a bed net); (3) weather (68% of care-givers would not use a bed net if the weather was hot), and (4) low density of mosquitoes (respondents who used bed nets as protection against mosquito nuisance were more likely not to use bed nets when mosquitoes were few than those who used bed nets for malaria protection (odds ratio (OR), 3.9; 95% confidence interval (CI), 1.4-12.0). Protection against malaria was the main reason children slept under bed nets. Children from households where bed nets were used for malaria protection were more likely to sleep under bed nets than children from households where nets were used as protection from mosquitoes only (OR, 2.7; 95% CI, 1.3-5.9). Other factors that affected children's bed net use were, age (users were significantly younger than non-users; chi(2)=7.9, degrees of freedom=1, P=0.005) and sufficiency of bed nets (OR, 2.0; 95% CI, 1. 3-7.0).

In the Cairns area of far north Queensland, Australia, the seasonal abundance of Anopheles farauti Laveran sibling species was studied at 6 locations, representing 3 habitat types, between August 1995 and September 1997. A total of 45,401 An. farauti s.l. was collected using CO2 + octenol baited CDC light traps, and consisted of 29,565 An. farauti No. 2, 14,214 An. farauti No. 3, and 1,622 An. farauti s.s. The relative abundance of all 3 species differed significantly by season and location. An. farauti No.2 was the dominant species except in Cairns, where An. farauti s.s. was most abundant, and at Ninds Creek, where An. farauti No. 3 predominated. The dominant species at each location was present year round, although peaks in seasonal abundance were observed. An. farauti s.s. populations were highest during the wet season (January-April). In lowland freshwater swamp habitats and 1 brackish location, An. farauti No. 2 was more abundant during the wet season. However, at the highland freshwater swamp habitat, populations of An. farauti No. 2 were highest during the late dry season and early wet season (October-December). There was a significant positive correlation of both temperature and rainfall with An. farauti s.s. and An. farauti No. 2 trap collections. There was a negative correlation between An. farauti No. 3 and temperature, indicating that this species may be more abundant during cool weather. Although there were significant relationships among weather variables and An. farauti s.l. collections, correlation values were generally low, indicating that other factors may contribute to variability among An. farauti sibling species trap collections.

Oviposition preference of the Australasian coastal malaria vector Anopheles farauti s.s. for water of varying salinity was determined in the laboratory to help understand the distribution and control of this species in the field. Numbers of eggs laid showed an inverse relationship with salinity; of 5 NaCl concentrations most eggs were laid in distilled water but some were laid in 3.17% NaCl (the salinity of seawater). The association of An. farauti with coastal areas occurs in spite of an aversion to salt water by ovipositing females. Factors other than salinity must be the primary determinants of distribution. Increasing the salinity of larval habitats will not totally prevent An. farauti from laying eggs. Elimination of this species may not occur unless salinity is kept high enough to prevent complete larval development.

Relationships among the genus Anopheles and its many sibling species-groups are obscure despite the importance of anophelines as the vectors of human malaria. For the first time, the interrelationships and the origin of Australasian members of the subgenus Cellia are investigated by a cladistic analysis of sequence variation within the mitochondrial cytochrome oxidase subunit II gene. Estimated divergence times between many Australasian and Oriental taxa predate the mid Miocene collision of Australasia and Southeast Asia. Phylogenetic analysis suggests that two-way exchanges with Oriental mosquitoes rather than only immigration may have been a characteristic of anopheline paleobiogeography in Australasia. The Australasian fauna is mostly included in a large clade. The medically important Punctulatus Group is monophyletic and appears derived from Oriental stock. Populations within this group from as far apart as Australia and Vanuatu were in contact in the recent past (i.e., 0.35-2.44 mya), supporting dispersal rather than vicariance explanations. Some support for the monophyly of the Myzomyia, Neomyzomyia, and Pyretophorus Series was found. However, the subgenera Anopheles and Cellia and the Neocellia Series are paraphyletic, but branch support at these taxonomic levels was poor. The COII gene shows promise for questions concerning alpha taxonomy but appears to be of limited use for resolving deeper relationships within the Anopheles.

Adult and larval specimens of anopheline mosquitos were collected throughout eastern Honiara during a study into risk factors for malaria illness in adults. Species identification was by morphology, DNA probes and by PCR. Only Anopheles farauti s.s. were identified from part-night landing catches carried out from 1900 to 2200 hours. Most mosquitos attracted to humans were culicines. The majority of anophelines (85%) were captured between 1900 and 2000 hours. An. farauti s.s. larvae were most common but one An. farauti No. 7, and ten An. punctulatus larvae were also collected.

Genomic DNA probes were made for two recently identified members of the Anopheles punctulatus complex; Anopheles sp. near punctulatus from Papua New Guinea and Anopheles farauti No. 7 from the Solomon Islands. The probes are species-specific and with the use of 32P labeling sensitive enough so that a squash blot of only a small segment of the mosquito is required for identification. The 119-basepair (bp) probe for An. sp. near punctulatus and the 1,106-bp probe for An. farauti No. 7 have been sequenced in full and the probes have been tested on field collected specimens. These probes now make it possible to distinguish An. sp. near punctulatus and An. farauti No. 7 from the other eight members of the An. punctulatus complex. A pan-species probe was also made from the 18S ribosomal DNA that binds to DNA from all members of the complex. These three probes complete the set required for distinguishing all known members of the An. punctulatus complex by DNA hybridization.

Although endemic malaria was eradicated from Australia by 1981, the vectors remain and transmission from imported cases still occurs. Climate modelling shows that global warming will enlarge the potential range of the main vector, Anopheles farauti sensu stricto; by the year 2030 it could extend along the Queensland coast to Gladstone, 800 km south of its present limit. Vigilance and a dispassionate assessment of risk are needed to meet this challenge.

Entomological studies were undertaken in three villages in the East Sepik Province of Papua New Guinea. The inhabitants of one village, Nanaha, had been treated with diethylcarbamazine (DEC) to reduce the prevalence and density of microfilaraemia of Wuchereria bancrofti. No intervention was undertaken in the other two villages, Yauatong and Musenau, in which bancroftian filariasis was present but with markedly different human prevalence rates and mean parasite densities. In Yauatong, infection rates in anopheline vectors (Anopheles punctulatus and An. koliensis) varied from 20.5 to 46.6% with infectivity rates of 0-1.4% while these rates were 10.9-14.3% and 0-1.1% respectively in Culex quinquefasciatus. In Nanaha after DEC treatment, infection rates were as high as 16.3% in An. koliensis and infectivity rates reached 7.0% for An. punctulatus despite a 45% reduction in the number of people with detectable microfilariae (mf) and a 94% reduction in mf density in those who remained positive.

Specimens identified morphologically as Anopheles punctulatus revealed 2 genetically distinct entities in samples collected in the Western Province of Papua New Guinea. We regard one of these species as conspecific with An. punctulatus and the other as a new species designated here as An. sp. near punctulatus.

Four species within the Anopheles punctulatus group of mosquitoes (Diptera: Culicidae) were identified by allozyme analysis of samples collected from thirty-three localities in Guadalcanal, Makira, Malaita, Temotu and Western Provinces in the Solomon Islands and six localities on Efate, Espiritu Santo, Maewo and Malekula Islands in Vanuatu. Three of these species are members of the An.farauti complex. A key is given to identify five species of the An.punctulatus group known to occur in the Solomon Islands using their isoenzyme characteristics. An.farauti No. 1 was widespread in coastal areas of the Solomon Islands and was the only species detected in Vanuatu, including Efate Island (where Faureville is the type locality of An.farauti Laveran sensu stricto). An.farauti No. 2 and An.punctulatus were common in the Solomon Islands in more inland areas. An.farauti No. 7, reported here for the first time, was found as larvae in freshwater at six localities on north Guadalcanal. Three other members of the An.punctulatus group which have been reported previously from the Solomon Islands: An.koliensis, An.renellensis and an electrophoretic variant of An.farauti sensu lato, were not found in our samples. Previously recognized vectors of malaria and bancroftian filariasis in the Solomon Islands are An.farauti No. 1 (i.e. An.farauti s.s.), An.koliensis and An.punctulatus s.s. Adult females of An.farauti No. 2 and An.farauti No. 7 were not attracted to human bait in areas where their larvae occurred, indicating that these two species are not anthropophilic and therefore unlikely to transmit human pathogens.

Genomic DNA probes were made for five members of the Anopheles punctulatus complex of mosquitoes found in Papua New Guinea. Specific DNA probes were developed for An. punctulatus, An. koliensis, and three sibling species, An. farauti No. 4, An. farauti No. 5, and An. farauti No. 6, by differentially screening total genomic DNA libraries of individual species and sibling species with homologous DNA against heterologous DNA labeled with 32P. Probes ranged from 273 to 630 bp. Identification of species can be made from squash or dot blots using only a segment of the mosquito (i.e, head, thorax, abdomen, or even legs), allowing for concurrent analysis of the remainder of the mosquito for other epidemiologic characteristics.

Electrophoretic keys are given for the six species of the Anopheles punctulatus complex (Diptera: Culicidae) known from Papua New Guinea plus An.farauti No. 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 as standards.

Among samples collected from nineteen localities in Papua New Guinea, we have identified six species within the Anopheles punctulatus complex of mosquitoes, by means of cellulose acetate allozyme electrophoresis. An.punctulatus Dönitz sensu stricto was collected from seven villages in the Madang area and from Buksak, Sausi Mission and an area 18 km SW of Tari; An.koliensis Owen from eight villages in the Madang area, from Popondetta and Brown River near Karema; and An.farauti No. 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 as An.farauti No. 4 from Gonoa and Hudini, Madang area; An.farauti No. 5 from Ketarabo near Goroka; and An.farauti No. 6 from Hiwanda near Tari. Three other known members of the complex, An.clowi Rozeboom & Knight, An.farauti No. 2 (Bryan, 1973) and An.farauti No. 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.

The dispersal of Culex annulirostris was studied during February 1986 in Griffith, N.S.W. using a mark-release-recapture technique. Parity was determined of recaptured females and a sample of the population at release. Parity rates of the 2 populations were comparable, and no significant differences were detected between the dispersal characteristics of the nulliparous and parous recaptured females. The maximum flight distance observed was 12 km, the limit of the trapping network. It was estimated that the mean distance traveled was 4.4 km and 36.6% (n = 377) of the population dispersed further than 5 km. The majority (81.2%, n = 377) of recaptures were taken within 2 days of release and the rate of dispersal of the population was estimated at 2.2 km/day.

Quantitative understanding of the transmission dynamics of lymphatic filarial parasites is essential for the rational planning of control strategies. One of the most important determinants of transmission dynamics is the relationship between parasite yield, the success rate of ingested microfilariae (mf) becoming infective larvae in a mosquito vector, and mf density in the source of the human blood meal. Three types of relationship have been recognized in human filaria/mosquito couples--limitation, facilitation and proportionality; facilitation has hitherto been observed only in the couple Wuchereria bancrofti/Anopheles gambiae in Burkina Faso, in experimental studies on a high density mf carrier. The present paper demonstrates facilitation in W. bancrofti/An. gambiae and W. bancrofti/An. arabiensis in lower mf density carriers in The Gambia and Tanzania, and in W. bancrofti/An. funestus in Tanzania. Facilitation was not found in An. melas in The Gambia nor in An. merus in Tanzania. Analysis of published data shows limitation at low level mf densities in W. bancrofti/Culex quinquefasciatus in Sri Lanka, and in the same couple in India. Limitation also occurs in Brugia malayi/Aedes togoi in experimental cats; proportionality occurs in B. malayi/Mansonia bonneae in Malaysia. The epidemiological significance of these host/parasite relationships is discussed, and supporting evidence for its validity is presented from the published results of large-scale control programmes.

The dispersal of Culex annulirostris, a major arbovirus vector in Australia, was studied in Griffith, N.S.W. using a mark-release-recapture technique. From an empirical model of dispersal, fitted to data on recaptured adults, the average distance dispersed was 6.8 km (95% c.l. 4.1-40.9 km), and 50% of the population dispersed 4.8 km or more. Maximum recorded dispersal was 8.7 km, and 2 individuals traveled more than 5 km in 1 day. The relevance of the findings to control strategy is discussed.

Animals homozygous for the recessive, pleiotropic, mutation hpy(hydrocephalic-polydactyl) develop hydrocephalus early in the postnatal period. The condition develops in the apparent absence of any overt indications of obstruction in the cerebrospinal fluid (CSF) drainage system suggesting a continued, inappropriate, secretion of CSF. Electron microscope investigations were undertaken to both characterize and quantify the cell types present in the choroidal epithelium of mutants and their wild-type littermates and to gauge their response to a prolonged (24 h) deprivation of water, which has severe adverse effects on the general body fluid balance. Collectively, the findings indicate that the cellular makeup of the choroidal epithelium of normal animals and the manner of its response to changing fluid conditions is more complex than formerly anticipated. Also that inferences derived from a simple extrapolation of findings from other fluid-transporting epithelia to choroidal cells are misleading and erroneous. In wild-type animals allowed free access to water light cells with clavate microvilli (secretory cells) predominated whereas, following water deprivation there was a preponderance of dark cells with filiform microvilli, abundant mitochondria, multivesicular bodies and osmiophilic droplets (resorptive cells). In hydrocephalic mutants, the makeup of the choroidal epithelium of non-water-deprived animals resembled that of water-deprived wild-type mice and showed little change following water deprivation. These findings suggest that while the choroidal cells of mutants are capable of mounting a response to conditions having adverse effects on water balance (i.e., hydrocephalus) their response falls short of the level needed to fully redress the imbalance and is not materially increased by imposition of further, stringent, conditions (e.g., water deprivation). Thus, the findings lend support to the view that the mutational event affects the regulation of solute transport rather than effecting abrogation of the membrane pump itself.

Laboratory observations were made on the uptake of microfilariae (mf) of Wuchereria bancrofti by Anopheles gambiae, An. arabiensis, An. merus and An. funestus. Over host mf densities ranging from 450/ml to 1735 mf/ml neither the percentage of mosquitoes ingesting mf nor the mean number of mf per mosquito was correlated to host mf density. All mosquito species damaged mf during ingestion but the proportion harmed was independent of host mf density. The mean proportion damaged was 0.67 in An. gambiae, 0.51 in An. merus, 0.47 in An. Arabiensis and 0.26 in An. funestus. A comparison of the mean number of undamaged mf ingested and the number of larvae in the thoracic muscles revealed that not all undamaged mf were able to reach the thoracic muscles.

In mice homozygous for the mutation hydrocephalic-polydactyl (hpy) ciliary axonemes from tracheal, oviducal, and ependymal lining cells showed a variety of abnormalities. Defects included: a deficiency of inner dynein arms, extra central tubules, a displacement of one outer doublet and/or the central tubules, and double axonemes. More than one kind of defect was seen in some axonemes. None of the types of defects observed in mutants were encountered in equivalent samples from non-mutant littermates. Except for the most common defect, the deficiency in dynein arms, which occurred to about the same extent (approximately 34%) in all three tissues, there were marked variations in frequency among the tissue types with respect to the other defects. In general, defects such as central tubule anomalies, displaced tubules, and double axonemes occurred with the highest frequencies in axonemes from tracheal epithelial cells and with the lowest frequencies in samples of oviducal epithelium. Fused cilia were seen only in ependymal cell samples. Some of the defects encountered were common to sperm flagella axonemes while others appeared restricted to somatic tissues, suggesting, perhaps, each tissue type may exert its own modulating influence on the expression of the mutant gene.

A survey of the antibody response to sporozoites of Plasmodium falciparum was carried out on plasma samples obtained from 20 mothers and their newborn infants living in The Gambia, West Africa. Serological assays detected antisporozoite antibodies in 90% (18/20) of the mothers, and similar titers were detected in 17/18 of their infants. The antisporozoite antibodies were gradually lost from the circulation of the babies until by approximately 6 months of age positive reactions against P. falciparum sporozoites were no longer detected. A similar pattern of acquisition and persistence of maternally-derived antisporozoite antibodies was noted in a neonatal rhesus monkey born to a female immunized with sporozoites of Plasmodium knowlesi.