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Biomedical subjects

R J Novak

Publications and source records attributed to R J Novak.

44 records · Page 3Linked to original sources
PubMed1990

Penetration rate of two pesticide carriers at a large used-tire storage facility in Chicago, Illinois.

During August 1987, a large and concentrated infestation of Aedes albopictus was discovered on the property of a tire recapper and gasket manufacturer in Chicago, IL, in a densely populated urban environment. The infestation called for special abatement procedures because of the large number of tires and the varied ways they were stacked. An effective method for delivering pesticides into the cavity of each tire is described. Corncob granules, when applied to stacked tires, effectively penetrated this larval habitat at rates of 85% in column-stacked piles, 93% in random-stacked piles and an average of 95% in shingle-stacked piles. By comparison, gypsum pellet carriers sustained penetration rates of 37% in shingle-stacked piles and 87% in random-stacked piles.

Aedes↗
PubMed1989

Oviposition behavior of Aedes triseriatus (Diptera: Culicidae): prevalence, intensity, and aggregation of eggs in oviposition traps.

The oviposition behavior of the treehole mosquito Aedes triseriatus (Say) was studied by counting the eggs laid in 300 oviposition traps weekly for one season (May-October) in Illinois. Eggs were aggregated spatially among traps each week, and temporally among weekly samples and for individual traps over weekly counts. Aggregation could be associated with a nonrandom dispersion pattern of oviposition events and with the oviposition of 20-60 eggs per event. Thus, females were laying clumps of eggs in an overdispersed manner. The greatest number of eggs was found in late July when prevalence (proportion of traps with eggs) and intensity (number of eggs per positive trap) peaked simultaneously. Intensity also peaked in May and prevalence peaked in mid-June and early September. When traps from which eggs were removed each week were compared with traps in which eggs were allowed to accumulate, prevalence was naturally higher in the latter group. However, the intensity of eggs was similar in both groups, indicating that more eggs were laid in traps from which eggs were removed. Thus, the presence of eggs on oviposition surfaces was associated with a decrease in further oviposition.

Aedes↗
PubMed1988

Panveld oviposition sites of floodwater Aedes mosquitoes and attempts to detect transovarial transmission of Rift Valley fever virus in South Africa.

Floodwater aedine mosquito eggs were recovered from soil samples taken from grassland depressions, called pans, in the Orange Free State Province of South Africa. A sedge, Mariscus congestus (Vahl) C.B.Cl., was a useful indicator of Aedes (Ochlerotatus) juppi McIntosh oviposition areas. No transovarial transmission of virus was demonstrated by Ae.juppi females reared from the eggs and allowed to feed shortly after eclosion on hamsters. No virus was recovered from 557 pools of 5425 adult Ae.juppi that were collected as eggs and reared to the adult stage in the laboratory. Rift Valley fever virus replicated to high titres in experimentally infected Ae.juppi females, but horizontal transmission experiments proved inconclusive.

Aedes↗
PubMed1985

Analysis of lipids by gas-liquid chromatography and complementary methods in four strains of Aedes aegypti mosquitoes.

Fatty acid composition of total lipids, neutral lipids and phospholipids of strains of Aedes aegypti were determined. The fatty acid composition of the strains differed quantitatively with regard to the relative percentage of commonly occurring fatty acids. Gas-liquid chromatography of fatty acid methyl esters showed 18:1 (oleic or elaidic) to be the predominant fatty acid. The fatty acid was identified as oleic by argentation thin-layer chromatography. A modified colorimetric method was used to determine tissue-free fatty acids. The lipids were predominantly triacylglycerol with lesser amounts of free fatty acids and decreasing amount of sterol ester, sterol, monoacylglycerol, diacylglycerol and hydrocarbons. The data show considerable lipid differences between the Caribbean strains (Les Cayes, Haiti, and San Juan, Puerto Rico) and the Jakarta (Indonesia) strain. The Shimba Hills (Kenya) strain was more similar to Jakarta than to the Caribbean strains. The results obtained with the different strains are discussed in relation to the established oral susceptibility to Dengue 1 and Dengue 2, yellow fever, and genetic analysis by isoenzyme studies.

Aedes↗
PubMed1985

Dengue transmission in two Puerto Rican communities in 1982.

Paired serologic, entomologic, and environmental surveys were performed in two Puerto Rican communities, Salinas and Manatí, in summer and fall 1982. Paired samples on 434 persons in Salinas and 324 persons in Manatí showed recent dengue infection rates of 35% and 26%, respectively. Ae. aegypti larval indices were higher in Salinas than in Manatí but were relatively high throughout both communities. Breteau indices in neighborhoods ranged from 43 to 172, and infection rates in the neighborhoods were 22% to 45%. With a multivariate technique, we analyzed possible associations of environmental variables with dengue incidence and prevalence of dengue antibody. Wood-constructed housing and low socioeconomic status were among the variables significantly associated with dengue incidence. Predictors of dengue antibody prevalence included socioeconomic level, tree height, shade, and window and door screens. Recent dengue infections clustered within the sampled members of households (P less than 0.05, binomial test). An estimated 35% of dengue infections were symptomatic, and no serious illnesses were reported. The potential for high dengue infection rates in Puerto Rico will continue unless substantial reductions in vector populations are achieved. Targeting dengue surveillance and vector control activities in areas with demonstrated environmental risk factors may limit transmission during future outbreaks.

Adolescent↗
PubMed1985

Evaluation of slow-release formulations of temephos (Abate) and Bacillus thuringiensis var. israelensis for the control of Aedes aegypti in Puerto Rico.

Formulations of temephos (Abate) and Bacillus thuringiensis var. israelensis (B.t.i.) on corncob and dried coconut husk carriers were tested for slow-release insecticide properties against Aedes aegypti larvae in Puerto Rico. Granular formulations of 5% and 10% temephos gave continuous larval control in used automobile tires for 27 to 124 days and 34 to 162 days, respectively. Temephos on radial sections of corncob and coconut husk chips gave good larval control in tires for 27 to 63 and 61 to 134 days, respectively, depending on the size of the carrier. Small (2-3 g) and large (3-5 g) coconut husk chips tested in 167 liter drums provided continuous control for 55 to 105 days, respectively. Granular formulations of B.t.i. controlled Ae. aegypti in tires for 19 to 33 days, and B.t.i. briquets exhibited larvicidal activity in large containers for 26 to 78 days.

Aedes↗
PubMed1985

High-resolution gradient polyacrylamide electrophoresis of isozymes of the mosquito, Aedes aegypti.

A procedure for high resolution electrophoresis of isozymes of the mosquito Aedes aegypti using nonlinear (2.5%-20%) polyacrylamide gradient gel slabs is described. Crude mosquito homogenates were electrophoresed on gradient and on homogeneous (7%) polyacrylamide gels and stained for esterase (EST), isocitrate dehydrogenase (IDH) and malate dehydrogenase (MDH). The resulting zymograms were compared to demonstrate the high resolving power of the polyacrylamide gradient gel system.

Aedes↗