Factors influencing the seasonal abundance of Aedes (Stegomyia) aegypti and the control strategy of dengue and dengue haemorrhagic fever in Thanlyin Township, Yangon City, Myanmar.

From June 2006 to May 2007, mosquito surveys were conducted in Thanlyin Township, Yangon City, Myanmar, to determine factors influencing the abundance of Aedes aegypti (Stegomyia aegypti) during the rainy season. Both the biological and environmental factors were included in this study. Increase in the hatchability of egg, larval survival rate, the shortened larval life-span and increased pupation rates supplemented by rainfall (i.e. continuous flooding of the containers, stimulate the continuous hatching of eggs) were observed for correlation with the increase in population density of Ae. aegypti during the rainy season in the study area. Control strategy of Ae. aegypti to analyze the infestation in the community (study area) with larval Ae. aegypti, integrated management measures including health education, attitudes and practices regarding dengue and dengue haemorrhagic fever, transmission of the disease and possible preventive measures, reduction of breeding sites and testing the efficacy of Bacillus thuringiensis israelensis (B.t.i.) with respect to the reduction level of Ae. aegypti larvae in breeding sources, were taken into consideration.

Factors influencing the seasonal abundance of Aedes (Stegomyia) aegypti and the control strategy of dengue and dengue haemorrhagic fever in Thanlyin Township,Yangon City, Myanmar

From June 2006 to May 2007, mosquito surveys were conducted in Thanlyin Township, Yangon City, Myanmar, to determine factors influencing the abundance of Aedes aegypti (Stegomyia aegypti) during the rainy season. Both the biological and environmental factors were included in this study. Increase in the hatchability of egg, larval survival rate, the shortened larval life-span and increased pupation rates supplemented by rainfall (i.e. continuous flooding of the containers, stimulate the continuous hatching of eggs) were observed for correlation with the increase in population density of Ae. aegypti during the rainy season in the study area. Control strategy of Ae. aegypti to analyze the infestation in the community (study area) with larval Ae. aegypti, integrated management measures including health education, attitudes and practices regarding dengue and dengue haemorrhagic fever, transmission of the disease and possible preventive measures, reduction of breeding sites and testing the efficacy of Bacillus thuringiensis israelensis (B.t.i.) with respect to the reduction level of Ae. aegypti larvae in breeding sources, were taken into consideration.

Hantavirus (Bunyaviridae) infections in rodents from Orange and San Diego counties, California.

During a screening program to determine the extent of hantavirus activity in Orange and San Diego Counties, California, serum samples from 2,365 rodents representing nine genera and 15 species were tested for hantavirus antibodies. A reverse transcription-polymerase chain reaction on selected seropositive rodents was used to identify the specific hantavirus. Rodents positive for Sin Nombre virus (SNV) antibodies by Western blot included 86 (9.1%) of 948 deer mice (Peromyscus maniculatus), four (1.5%) of 275 California mice (Peromyscus californicus), one (0.5%) of 196 cactus mice (Peromyscus eremicus), 51 (12.2%) of 417 harvest mice (Reithrodontomys megalotis), and five (12.5%) of 40 California voles (Microtus californicus). All other specimens tested were negative for hantavirus antibodies. There was a correlation between age and sex of the reservoir host and prevalence of SNV antibody, especially among male deer mice and harvest mice. Few seasonal trends in antibody prevalence were observed and continued maintenance of SNV and El Moro Canyon virus was found at several foci over a 4-5-year period. Isla Vista virus was also found in voles and represents the first recorded in Orange County. Microhabitat selection on the part of these rodents based on plant density, plant height, and availability of food plants may explain, to some extent, all of the hantavirus-positive foci throughout the study area over a broad geographic range and the lack of antibody-positive rodents in dense chaparral, woodland, and riparian areas. The majority of rodents positive for SNV was identified from localities along coastal bluffs and the foothills of the Santa Ana Mountains, where trap success was high and P. maniculatus represented 43% of all rodents collected. Several residential, commercial, and industrial sites exist in these areas and the potential health risk should not be overlooked. This study represents an in-depth analysis of the prevalence, host distribution, and characteristics of rodent populations infected by three hantaviruses within a small, well-defined, geographic area.

An overview of plague in the United States and a report of investigations of two human cases in Kern county, California, 1995.

Plague was confirmed in the United States from nine western states during 1995. Evidence of Yersinia pestis infection was identified in 28 species of wild or domestic mammals. Thirteen of the plague positive species were wild rodents; 15 were predators/carnivores. Yersinia pestis was isolated from eight species of fleas. Seven confirmed cases of human plague were reported in 1995 (New Mexico 3; California 2; Arizona and Oregon 1 each). Five of the seven cases were bubonic; one was septicemic and one a fatal pneumonic case. Months of onset ranged from March through August. In California, during 1995, plague was recorded from 15 of the 58 counties. Over 1,500 animals were tested, of which 208 were plague positive. These included 144 rodents and 64 predators/carnivores. Two confirmed human cases (one bubonic and one fatal pneumonic) occurred, both in Kern County. Case No. 1 was reported from the town of Tehachapi. The patient, a 23 year-old male resident, died following a diagnosis of plague pneumonia. The patient's source of plague infection could not be determined precisely. Field investigations revealed an extensive plague epizootic surrounding Tehachapi, an area of approximately 500-600 square miles (800-970 square kilometers). Case No. 2 was a 57 year-old female diagnosed with bubonic plague; she was placed on an antibiotic regimen and subsequently recovered. The patient lives approximately 20 miles (32 km) north of Tehachapi. Field investigations revealed evidence of a plague epizootic in the vicinity of the victim's residence and adjacent areas. Overall results of the joint field investigations throughout the entire Kern county area revealed a high rate of plague positive animals. Of the numerous samples submitted, 48 non-human samples were plague positive.

Seroepidemiologic studies of hantavirus infection among wild rodents in California.

A total of 4,626 mammals were serologically tested for antibodies to Sin Nombre virus. All nonrodent species were antibody negative. Among wild rodents, antibody prevalence was 8.5% in murids, 1.4% in heteromyids, and < 0.1% in sciurids. Of 1,921 Peromyscus maniculatus (deer mice), 226 (11.8%) were antibody positive, including one collected in 1975. The highest antibody prevalence (71.4% of 35) was found among P. maniculatus on Santa Cruz Island, off the southern California coast. Prevalence of antibodies among deer mice trapped near sites of human cases (26.8% of 164) was significantly higher than that of mice from other sites (odds ratio = 4.5; 95% confidence interval = 1.7, 11.6). Antibody prevalence increased with rising elevation (> 1,200 meters) and correlated with a spatial cluster of hantavirus pulmonary syndrome cases in the Sierra Nevada.

High doses of caffeine impair performance of a numerical version of the Stroop task in men.

The effects of caffeine ingestion on mid-morning cognitive performance were investigated in thirty-two male subjects. These were given drinks containing either no caffeine, 125 mg caffeine (mean dose: 1.38 mg/kg), or 250 mg caffeine (mean dose: 3.45 mg/kg) and were tested on three tasks: 1) free recall of supraspan word lists, 2) a response time (pointing) task and 3) a numerical Stroop task. There were no significant group differences on the recall task or in response times, but subjects having the higher caffeine dose were seriously impaired on the Stroop test, making particularly slow responses. Caffeine may have a deleterious effect on the rapid processing of ambiguous or confusing stimuli, and this may account for its clear effect on the Stroop test than on other cognitive tests used hitherto.

Introduction of the scorpion Centruroides exilicauda into California and its public health significance.

The bark scorpion, Centruroides exilicauda, formerly C. sculpturatus, is a native of Arizona and adjacent parts of New Mexico in the United States, and Baja California and Sonora in Mexico. A few specimens have been captured on the California side of the Colorado River. The general biology of this scorpion is discussed and the introduction of the arthropod into three California counties, probably in trailer paraphernalia and dune buggies, is described. Four probable stings by C. exilicauda in California and their public health significance are presented.

Pharmacokinetic profile of benoxaprofen in subjects with normal and impaired renal function, prediction of multiple-dose kinetics.

The pharmacokinetic profile of benoxaprofen given as a single oral dose of 600 mg was determined comparatively in 5 healthy volunteers and in 15 patients with various degrees of renal insufficiency (5 of whom were undergoing maintenance hemodialysis). In normal subjects, the half-absorption period (Ka) was 0.63 hours. A mean maximum concentration of 47.3 micrograms/ml could be predicted at 3.6 hours after the dose intake. Serum level decrease was particularly slow. The overall elimination rate constant, Ke, was 0.0234(h-1) and biologic half-life amounted to 28.8 hours. Values for total clearance (Ct=4.8 ml/min/1.73 m2) and renal clearance (Cr=1.6 ml/min/1.73 m2) were low. Of the administered dose of benoxaprofen, 13.9% was recovered in the urine over a 24-hour period. Renal insufficiency did not induce major changes in pharmacokinetic parameters. Under such conditions, it seems advisable to reduce the dose to one-half only in patients with a creatinine clearance of less than 10-20 ml/min/1.73 m2. Predicted serum levels theoretically achieved after repeated administration of a 600-mg dose of benoxaprofen every 6, 12, 24, 36 and 48 hours were calculated. From this evaluation, it appears that therapeutically effective and adequate levels could be obtained after administration of a 600-mg dose every 12 ot 24 hours.

Dislocations in spinel and garnet high-pressure polymorphs of olivine and pyroxene: implications for mantle rheology.

The meteorite Tenham was observed by transmission electron microscopy and ringwoodite and majorite, the high-pressure polymorphs of olivine and pyroxene, were identified. Ringwoodite contains antiphase boundaries and straight dislocations that are probably dissociated. Mantle flow of spinel might proceed by pure climb, and whole-mantle convection may be possible if the grain size is small enough.