Larval rearing water and preexisting eggs influence oviposition by Aedes aegypti and Ae. albopictus (Diptera: Culicidae)

Two-choice laboratory bioassays were used to evaluate oviposition responses of gravid Aedes aegypti (L.) and Ae. albopictus (Skuse) to larval rearing water and eggs from prior egg deposition. Oviposition responses by female Ae. aegypti were similar between larval water from Ae. aegypti and water controls but significantly greater to larval water from Ae. albopictus (12.2%) compared with water controls. Oviposition by Ae. albopictus females increased significantly in response to larval water from either species compared with water controls with increases of 15.1% to Ae. aegypti larval water and 17.6% to Ae. albopictus larval water. Oviposition responses of gravid Ae. aegypti and Ae. albopictus were evaluated in the presence of preexisting conspecific and heterospecific eggs on strips of oviposition paper. Significantly more eggs were laid by gravid Ae. aegypti females on oviposition paper containing either Ae. aegypti or Ae. albopictus eggs than on oviposition paper without eggs. In contrast, oviposition responses of gravid Ae. albopictus females were unaffected by the presence of eggs of either species.     

Laboratory and field evaluations of oviposition responses of Aedes albopictus and Aedes triseriatus (Diptera: Culicidae) to oak leaf infusions

Organic infusions created by fermenting white oak (Quercus alba L.) leaves in water were evaluated as sources of attractant odorants and contact oviposition stimulants for gravid Aedes albopictus (Skuse) and Aedes triseriatus (Say). Infusions were bioassayed in the laboratory by giving single females a choice of ovipositing in 1 container with infusion and 7 containers with water. Ae. albopictus laid significantly more eggs in containers with infusion, regardless of concentration (dilutions ranging from 10 to 100%) or age (fermentation periods of 7, 28, 60 d), than in containers holding water. The largest proportion of eggs (76.8%) was deposited in response to a 60% concentration of 7-d-old infusion. In contrast, Ae. triseriatus exhibited variable oviposition responses but generally deposited the largest number of eggs in only a few concentrations of older age infusions. In binary "sticky screen" bioassays, there was no difference between the numbers of females attracted to infusion or water, indicating that oviposition responses to infusion were mediated by contact chemostimulants rather than by attraction to odorants. Oviposition responses to infusions by field populations of Ae. albopictus and Ae. triseriatus in Raleigh, NC, were evaluated with pairs of oviposition traps, one containing infusion and the other containing water. Generally, Ae. albopictus laid significantly more eggs in ovitraps containing infusion regardless of its age (7, 28, and 60 d old) or the mass of leaves fermented (126 g = 1x or 504 g = 4x) than in water. In contrast, Ae. triseriatus deposited an equivalent number of eggs in traps containing water or 1x, 80% infusion regardless of its age; however, the oviposition response to ovitraps containing 4x, 7-d-old, 50% infusion was significant. Placement of an automobile tire behind an ovitrap did not increase the number of Ae. albopictus eggs laid in ovitraps containing 4x, 7-d-old, 50% infusion or water relative to ovitraps without a tire. Our research indicates that baiting ovitraps with oak leaf infusion would increase the sensitivity of surveillance efforts for Ae. albopictus and Ae. triseriatus.     

Breeding places of Aedes scapularis (Diptera: Culicidae) in artificial containers

Breeding places of Aedes scapularis were found in the Ilha Comprida and Pariquera-A?u counties of S. Paulo State, Brazil. They included several types of artificial water container. As 270 (250 larvae and 20 pupae) immature forms were collected, the hypothesis is raised that behavioral change is occurring as a secondary adaptation, as a consequence of the anthropic environment. This tends toward a reduction in ground breeding places and, at the same time, to an increase in the number of artificial containers. So the synanthropic tendence of thus mosquito may be favored by or even be a result of the man-made environment. Reference is made to the epidemiological consequences of this phenomenon for encephalitis transmission specifically for the Southeastern region of Brazil.     

Establishment and characterization of three cell lines from Aedes triseriatus (Diptera: Culicidae)

The objectives of this study were to develop sex-, age-, and body size-specific nomograms and partition values for upper and lower limits of M-mode echocardiographic aortic root measurements derived from a large population-based cohort. The study sample consisted of 1433 male and 1816 female participants in the Framingham Heart Study and Framingham Offspring Study who were normotensive and free of clinically apparent heart disease at the baseline examination. Aortic root measurements were obtained by M-mode echocardiography by a leading-edge to leading-edge technique. The relations of age and measures of body size with aortic root dimensions were evaluated with sex-specific correlations and multiple stepwise linear regression analyses. Age was the most important determinant of aortic root size in both men and women in the multivariable regression models. Models with age and body surface area yielded R2 values of 0.214 in men and 0.222 in women. Models with age and height yielded lower R2 values of 0.136 in men and 0.181 in women. Thus aortic root dimensions vary widely with the age, sex, and body size of individuals. Sex-specific reference nomograms of aortic root dimensions in relation to age and body size (body surface area or height) are presented to facilitate the detection of abnormalities of aortic root size.     

Predation on Aedes aegypti (Diptera: Culicidae) by Theridion rufipes (Araneae: Theridiidae) in Puerto Rico

A total of 110 total knee replacements (TKRs) was randomised to receive either a cemented or an uncemented prosthesis. Postoperative venography at five to seven days was used to compare the prevalence, site and size of deep-vein thrombosis (DVT). We also compared the findings with those of postoperative venography in a group of patients with cemented total hip replacements (THRs). The total prevalence of DVT was significantly greater after uncemented (81%) than after cemented TKR (55%). Both knee groups had a significantly higher prevalence of DVT than in cemented hip replacements (32%). We found no difference in the proportion with proximal DVT in the three groups (14%, 15% and 16%). The median length of the thrombi was significantly greater after cemented (26.5 cm) than after uncemented TKR (11 cm) or after cemented THR (7 cm). This difference was mainly due to greater lengths of distal rather than proximal thrombi. We conclude that the use of cement may affect the formation of DVT after joint replacement, but does not appear to lead to an increased incidence.     

Evaluation of commercial insect repellents on human skin against Aedes aegypti (Diptera: Culicidae)

An olfactometer was used to evaluate the efficacy of selected commercial insect repellent products against Aedes aegypti (L.). A comparison of 12 commercial repellent products was made on human skin. The products tested included 2 natural oil insect repellent formulations (Buzz Away and Green Ban) containing plant extracts, 2 proprietary products (Skin-So-Soft lotion and bath oil), and 8 commercial deet preparations in various concentrations and forms of spray, aerosol, stick, cream, and lotion. Behavioral responses and time to probe were determined in triplicate using 10 female mosquito challenges per replicate for each product. Generally, products with higher concentrations of deet were found to have longer repellence times. OFF spray and Muskol lotion offered the longest repellence times. However, there was no significant difference in time for mosquitoes to probe among the formulations. Skin-So-Soft lotion and bath oil were not as effective as deet in repelling Ae. aegypti. Natural oil insect repellent formulations offered essentially no repellency against Ae. aegypti. This is a simple and reproducible method to evaluate the efficacy of insect repellents and is recommended for preliminary screening of new insect repellents or formulations.     

Nutritional reserves of autogenous and anautogenous selected strains of Aedes albopictus (Diptera: Culicidae)

Autogeny in Aedes albopictus (Skuse) females was increased from 5% in wild-type parental stock to 84% by selection through 20 generations and was decreased to 0% by selection through nine generations. Concomitantly, the mean number of eggs per female that matured autogenously increased from 6.4 to 18.3 in sugar-fed mosquitoes that developed eggs. Although the duration of the larval period of the two strains was not different, autogenous females emerged with greater amounts of metabolizable protein and lipid and total available energy reserves than did anautogenous females, but with lesser amounts of glycogen. Dry weights did not differ significantly. The difference in the energy reserves between strains was slightly more than the total energy invested in 20 autogenous eggs. Autogenous females survived 1.3 d longer than did anautogenous females when starved from emergence.     

Physical factors influencing the oviposition of Lutzomyia migonei (Diptera: Psychodidae) in laboratory conditions

Anthropometric and demographic characteristics are important determinants of exercise performance in healthy subjects, but their influence has not yet been studied in severe chronic heart failure, although peak oxygen uptake is frequently assessed in such patients for prognostic purposes. The aim of the present analysis was to examine the association between peak oxygen uptake and age, gender, and measures of body size in patients with severe chronic heart failure. We selected 122 (99 male) adult heart transplant candidates who were able to perform a bicycle ergometer test with respiratory gas analysis until voluntary fatigue. Peak oxygen uptake was higher in male than in female patients, both before and after adjustment for weight. In single regression analysis on the total study population, peak oxygen uptake was positively related to weight and to height, but inversely to age (r = 0.59 (P < 0.001), 0.42 (P < 0.001), and -0.33 (P < 0.001), respectively). Multiple stepwise regression analysis identified weight (P < 0.001), age (P < 0.001), and gender (P < 0.01) as independent determinants of peak oxygen uptake (cumulative R2 = 0.45). Similar to the findings in healthy subjects, peak oxygen uptake of patients with severe chronic heart failure is influenced by anthropometric and demographic characteristics.     

Insecticide impregnated cotton fabrics of different hydrophobicity against Aedes aegypti (Diptera:Culicidae)

Residual efficacy of synthetic pyrethroids, viz, permethrin, deltamethrin, lambdacyhalothrin and an insect repellent DEPA in cotton fabrics of different hydrophobicity was tested against Aedes aegypti. Amino silicone was used for enhancing the hydrophobicity of the fabrics. The results showed that there was an increasing trend in repellency/feeding deterrency with the increase in hydrophobicity up to 17.5 weeks at an optimum level of 30g/l. The adulticidal effect lasted for 1 to 4 weeks and this lower residual activity was attributed to the repellency of the treated fabrics. The results indicated that the residual efficacy of cotton fabrics could be enhanced by treating with an hydrophobic agent that increases the availability of the insecticide on the surface.     

Enzymatic variability in natural populations of Aedes aegypti (Diptera:Culicidae) from Brazil

Yellowfever mosquitoes, Aedes aegypti (L), were collected from 3 towns located within 70 km of each other in the State of Sao Paulo to evaluate the protein variability of natural populations. Electrophoretic analysis permitted the identification of 6 loci responsible for the production of leucine aminopeptidase, 3 for esterases and malic enzyme, 2 for malate dehydrogenase, isocitrate dehydrogenase and alpha-glycerophosphate dehydrogenase, and 1 for phosphoglucomutase. For the 3 populations, the range for alleles per locus (1.63-2.03), the proportion of polymorphic loci (37.5-50.0%), and the expected mean heterozygosity (0.48-0.53) were greater than reported for other populations of A. aegypti. Although the 3 populations were similar genetically, the 1.8% differentiation was significant.     

Selection-dependent trends of autogeny and blood feeding in an autogenous strain of Culex tarsalis (Diptera:Culicidae)

The purpose of this report is to examine the outcomes for patients with an underlying diagnosis of malignancy who have had Greenfield vena caval filters placed for protection from pulmonary embolism, and to identify areas requiring further study. This was a retrospective review of data obtained from the Greenfield filter registry and the University of Michigan Tumor Registry for 166 patients treated at the University of Michigan Medical Center between January 1988 and June 1994. The 84 men and 82 women (mean age 57.8 years) had a mean survival time of 10 (range 1-68) months. This differs significantly from patients in the filter registry who do not have malignancy (P<0.0001). Some 51% experienced recurrence of their malignancy at a mean of 20 months; this timing corresponds to development of new or recurrent thrombembolism and filter placement. Distant metastases were present in 72% of patients at the time of filter placement. In conclusion, as anticipated, filter patients with malignancy have a significantly shorter survival time than those with other concurrent diseases. A temporal association between the progression of the malignancy and the occurrence of thromboembolism is observed in this population and requires further study. Future studies regarding the use of vena caval filters in these patients and the role of diagnostic screening for deep venous thrombosis and occult recurrence of malignancy should focus on efficacy, safety, cost and patient quality of life rather than on survival.     

Influence of plant abundance on nectar feeding by Aedes aegypti (Diptera: Culicidae) in southern Mexico

The availability of flowering plants affected the sugar feeding rates of female Aedes aegypti (L.) in 4 areas of a small city in southern Mexico. The proportion of mosquitoes containing sugar varied from 8 to 21% in 4 areas in direct relation to blooming plant abundance. Human density was similar in the 4 areas (range, 3.9-5.4 per house), whereas the number of flowering plants per house increased on the outskirts (range, 3.1-5.4 plants per house). Equal proportions of sugar positive females were nulliparous or parous, indicating similar sugar feeding at any age. In addition, nearly 60% of positive females were at the Christophers stage II, indicating a greater need for flight fuel during the early stages of egg development. We conclude that Ae. aegypti feeds frequently on nectar and that this activity is modulated by nectar availability.     

Serotonin depletion affects blood-feeding but not host-seeking ability in Aedes triseriatus (Diptera: Culicidae)

The host-seeking and blood-feeding abilities of Aedes triseriatus (Say) were evaluated after treatment with the amine depleting drugs alpha-methyl-tyrosine (AMT) and alpha-methyl-tryptophan (AMTP). High-performance liquid chromatography with electrochemical detection (HPLCED) was used to demonstrate that AMTP depleted serotonin levels, whereas AMT reduced dopamine levels. The host-seeking ability (evaluated with an olfactometer) of Ae. triseriatus was not altered by treatment with either AMT or AMTP. Blood-feeding success was reduced significantly by either oral administration or injection of AMTP. Mosquitoes treated with AMTP responded positively when placed in close proximity to a host (rabbit), but fewer treated than untreated mosquitoes fed to repletion or fed at all. Those feeding to repletion took longer to do so. No differences in feeding ability were observed between control and AMT-treated mosquitoes. These observations indicate that serotonin plays a role in modulating blood-feeding activities of Ae. triseriatus.     

Control of larval Aedes aegypti (Diptera: Culicidae) by cyclopoid copepods in peridomestic breeding containers

HIV infection and AIDS create a unique dilemma for women in their potential for vertical transmission of these conditions. Selected feminist perspectives in ontology, epistemology, and axiology are reviewed to illuminate possible social, cultural, and political circumstances of these women. Drawing both on these perspectives and various sources of data about women with HIV/AIDS, some implications for nursing complete this discussion.     

1st isolation of Aedes (Ochlerotatus) sticticus (Diptera, Culicidae) in the Po-Venetian valley

Aedes sticticus is recorded for the first time in northern Italy. The species was collected in some relict woods mainly at sea level in the Po-Venetian valley (Northern-Italy). Larval growth took place in residual puddles originated by rain or river floods. The most abundant adult emergence was observed in April or May. Minor earlier or later adult emergencies were observed depending from egg submersion and temperature. Data on larval chetotaxy are presented.     

Susceptibility of three laboratory strains of Aedes albopictus (Diptera: Culicidae) to Japanese encephalitis virus from Taiwan

An 11-year-old boy developed florid reactive periostitis several years after minor trauma. The symptoms responded initially to antibiotics, but after cessation, rapidly recurred and progressed, requiring a ray amputation to relieve the pain and to achieve a functional hand. The reactive periostitis affected the volar aspect of two adjacent phalanges with sparing of the intervening joint, confirming that this is a reactive process rather than a benign neoplasm.     

Larvicidal activity of the entomopathogenic fungus Tolypocladium cylindrosporum (Deuteromycotina: Hyphomycetes) on the mosquito Aedes triseriatus and the black fly Simulium vittatum (Diptera: Simuliidae)

Laboratory bioassays evaluated the pathogenicity of the entomopathogenic fungus Tolypocladium cylindrosporum against Aedes triseriatus. All larval instars were found to be susceptible at temperatures from 18 to 25 degrees C. Blastoconidia were more virulent than conidia. Mortality was proportional to exposure time in assays using blastoconidia. Blastoconidia and exposure time appear to be a more adequate method for bioassay of T. cylindrosporum virulence than the standard procedure of using conidia and continuous exposure. Tolypocladium cylindrosporum was also active against Simulium vittatum black fly larvae, but the mortality recorded was much lower than with mosquito larvae.     

Aedes triseriatus (Diptera: Culicidae) and La Crosse virus. II. Modification of mosquito feeding behavior by virus infection

Intact and ovariectomized female rats were bilaterally lesioned in the anterior part of the medial amygdaloid nucleus (AMN) at 15, 21 or 26 days of age. The onset of puberty and the LH concentration in the peripheral serum on the third day after lesioning, respectively, were recorded. Damage to the AMN on day 15 induced a significant delay of vaginal opening and the first puberal ovulation and suppressed completely the castration-induced increase of LH secretion. In contrast, females lesioned on day 21 showed true precocious puberty and a significant elevation of the LH level as compared to the ovariectomized controls. The LH-inhibiting effect of s.c. administered estradiol benzoate (0.05 micrograms/100 g/day) was not diminished by lesions produced at this age. Neither the onset of puberty nor the LH concentration were influenced by lesioning of the AMN on day 26. Estimation of the LH concentration in untreated female rats revealed a distinct decline between 19 and 23 days of age followed by a significant increase between days 24 and 26. The findings indicate a transient LH-inhibiting activity of the medial amygdala in three-week-old female rats that is not related to the negative estrogen feedback. In other species, too, a temporary inhibitory action of the central nervous system may play a significant role in the prepuberal control of gonadotropin secretion.     

The mosquitoes of Yellowstone National Park (Diptera:Culicidae)

Although antibodies to viruses in both the epizootic hemorrhagic disease virus (EHDV) and bluetongue virus (BTV) sero-groups have been reported from white-tailed deer (Odocoileus virginianus) in Texas (USA), there are few reports of hemorrhagic disease (HD) in these populations. To understand the extent and diversity of exposure to the North American EHDV and BTV serotypes in these deer populations, we serologically tested 685 white-tailed deer collected from November 1991 through March 1992 throughout their range in Texas. Overall, 574 (84%) of deer had antibodies to EHDV or BTV. Prevalence estimates varied according to ecological region, from 57% in the Gulf Prairies to 100% in the northwest Edwards Plateau. Based on serum neutralization tests, the deer had evidence of previous exposures to multiple EHDV and BTV serotypes, with evidence of exposure to two to five serotypes detected in each ecological region. The apparent lack of HD in relation to this high antibody prevalence cannot be explained, but may be related to enzootic stability in which a near perfect host-virus relationship exists.