ABSTRACT
Dengue fever (DF), one of the mostimportant emerging arboviral diseases, is transmitted through the bite ofcontainer breeding mosquitoes <i>Aedesaegypti</i> and <i>Aedes albopictus</i>. Ahousehold entomological survey was conducted in Dhaka from August throughOctober 2000 to inspect water-holding containers in indoor, outdoor, androoftop for <i>Aedes</i> larvae. Theobjective of this study was to determine mosquito productivity of eachcontainer type and to identify some risk factors of the households to beinfested with <i>Aedes</i> larvae. Of 9222 households inspected, 1306(14.2%) were positive for <i>Aedes</i> larvae. Of 38 777wet containers examined, 2272 (5.8%)were infested with <i>Aedes</i> larvae. Containers used for reserving water,such as earthen jars, tanks, and drums were the most essential containers forlarval breeding. Tires in outdoor and rooftop of the households were alsoimportant for larval breeding. Although present in abundant, less importancewas indicated for buckets. Independent household, having water storage systemin the house, and having fully/partly shaded outdoor premise were foundsignificantly associated with household infestation of <i>Aedes</i> larvae. Identification and subsequent elimination of the most productive containers ina given area may potentially reduce mosquito density below a level at whichdengue transmission may be halted.
ABSTRACT
Dengue fever (DF), one of the most important emerging arboviral diseases, is transmitted through the bite of container breeding mosquitoes <i>Aedes aegypti</i> and <i>Aedes albopictus</i>. A household entomological survey was conducted in Dhaka from August through October 2000 to inspect water-holding containers in indoor, outdoor, and rooftop locations for <i>Aedes</i> larvae. The objective of this study was to determine mosquito productivity of each container type and to identify some risk factors of households infested with <i>Aedes</i> larvae. Of 9,222 households inspected, 1,306 (14.2%) were positive for <i>Aedes</i> larvae. Of 38,777 wet containers examined, 2,272 (5.8%) were infested with <i>Aedes</i> larvae. Containers used to hold water, such as earthen jars, tanks, and drums were the most common containers for larval breeding. Tires in outdoor and rooftop locations of the households were also important for larval breeding. Although present in abundance, buckets were of less importance. Factors such as independent household, presence of a water storage system in the house, and fully/partly shaded outdoors were found to be significantly associated with household infestation of <i>Aedes</i> larvae. Identification and subsequent elimination of the most productive containers in a given area may potentially reduce mosquito density to below a level at which dengue transmission may be halted.
ABSTRACT
A concentration of specimen is recommended for the effective recovery of Mycobacterium tuberculosis [MTB], but the bacteriological efficiency is not well evaluated. The present study evaluated the factors contributing to concentration efficiency of centrifugation and bead-based technique [TB-Beads; Microsens, UK] to recover MTB by using simple in vitro specimens. Four specimens were prepared [6.5 × 103; 8.1 × 104; 7.9 × 105; and 6.4 × 106 cfu/mL] of different concentrations with or without 5 × 104 of THP-1 cells [RIKEN BRC, Japan]. Specimens were subjected to centrifugation at 2000, 3000, and 4000g for 15 min, and to TB-Beads. The concentration and recovery rate were calculated to evaluate the efficiency of each method. The specimens containing a higher number of bacteria and THP-1 cells had a tendency to yield a higher concentration and recovery rate [p = 0.001-0.083]. MTB was recovered more efficiently with THP-1 cells from the 6.5 × 103 cfu/mL specimen by centrifugation [p= 0.001] than without them; 24.7-54.4% of MTB were recovered with THP-1 cells by centrifugation at 3000g for 15 min, while the recovery using TB-Beads was a maximum of 12.7%. The efficiency of centrifugation depends on the bacterial density and the co-existence of THP-1 cells. The efficiency of TB-Beads was not as high as centrifugation