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Biomedical subjects

D Strickman

Publications and source records attributed to D Strickman.

51 records · Page 3Linked to original sources
PubMed1993

Three simple devices for preventing development of Aedes aegypti larvae in water jars.

We developed three types of covers that are easily fabricated from plastic screen locally manufactured in Thailand. The covers were designed to permit normal use of water jars for drinking, utility water uses, and water storage. Tests of the covers in the laboratory and field demonstrated that they could completely prevent successful development of Aedes aegypti (L.) in water jars. Initial experience in a village setting demonstrated that these devices were readily manufactured and used in a community-based program. Village residents adapted the covers to local patterns of water use, collecting rainwater through the screen and adjusting cover use to water depth.

Aedes↗
PubMed1992

Female Aedes aegypti (Diptera: Culicidae) in Thailand rarely feed on sugar.

Female Aedes aegypti (L.) of two different body sizes and provided with different diets (20% sucrose, water only, or 20% sucrose + human blood) were marked and released together in a rural Thai village. Recaptured marked and unmarked (wild) adults were tested for fructose by the cold-anthrone reaction. Both released and wild females showed a low frequency of sugar feeding in nature; both small-bodied and large-bodied individuals failed to sugar feed significantly. Marked females released with sugar in their crop utilized this energy source over the following 2-3 d but failed to replenish it. In contrast, about one-third of wild, resting males showed evidence of recent sugar feeding. This indicated that the absence of plant sugar in females was not caused by a shortage of nectar sources in this rural domestic environment. Presumably, the nonutilization of plant sugar as an energy source increases the frequency of blood feeding and, therefore, the vectorial capacity of Ae. aegypti.

Aedes↗
PubMed1990

Illustrated key to the female anopheline mosquitoes of Central America and Mexico.

An illustrated key to the female anopheline mosquitoes of Central America from western Panama to the southern border of the United States is presented with a taxonomic summary and distribution table. Thirty-nine species and one subspecies are treated: Chagasia (1), Anopheles (Anopheles) (25 and one subspecies), An. (Kerteszia) (2), An. (Lophopodomyia) (1), An. (Nyssorhynchus) (9) and An. (Stethomyia) (1).

Anatomy, Artistic↗
PubMed1989

Biosystematics of larval movement of Central American mosquitoes and its use for field identification.

Means of locomotion of 48 species of larval mosquitoes was observed using cinematography in Panama, Honduras and neotropical Mexico. General observation led to a classification of movement into path, frequency, position and mechanism. Examination of high speed film sequences (64 frames per second) revealed that all species use the same basic mechanism of flexing, which consists of a power and a recovery phase. The entire flexing cycle is a modification of undulatory propulsion commonly observed in other animals (e.g., snakes, ceratopogonid larvae). Variations on the basic patterns of mosquito larval flexing mainly concern the speed of the power stroke and the degree of sinusoid curvature prior to the power stroke. Four basic patterns of larval flexing were discerned: irregular, sinuous, semisymmetric and anopheline. Some taxonomic groups appear to use one pattern of flexing exclusively or with few exceptions. Examples include Culex (Melanoconion) with sporadic irregular flexing, Cx. (Culex) with sustained irregular flexing, Haemagogus with slow sinuous flexing and Anopheles with anopheline flexing. Other groups (e.g., Aedes (Howardina), Cx. (Carrollia), Deinocerites, and Wyeomyia (Wyeomyia] use a number of patterns of flexing. Observation of flexing and other aspects of larval movement can be an important addition to geographical, habitat and morphological considerations in field identifications.

Animals↗
PubMed1988

Rate of oviposition by Culex quinquefasciatus in San Antonio, Texas, during three years.

Two artificial oviposition sites containing aged alfalfa pellet infusion were exposed to natural populations of Culex quinquefasciatus in San Antonio, Texas, for 3 years. Numbers of egg rafts were counted daily and compared to weather data from a nearby station. Egg rafts were generally most numerous in summer months, declining in fall and increasing in spring. Oviposition occurred in winter only when temperatures were high enough. A particularly severe winter in 1983-84 reduced winter activity, but was followed by a great increase in oviposition in late spring. In summer, increases of oviposition were correlated with rainfall 2 to 3 weeks before the time of oviposition. Rainfall at the time of oviposition appeared to decrease oviposition. On a seasonal basis, lack of rainfall in the summer of 1984 was correlated with a decrease in oviposition.

Animals↗
PubMed1986

Seasonal and meteorological effects on activity of Chrysops variegatus (Diptera: Tabanidae) in Paraguay.

Activity of adult, female Chrysops variegatus was studied for 17 months near Aregúa, Paraguay. The population was sampled by walking along a forest path while swinging an insect net. Results of sampling indicated that this species followed no seasonal pattern of activity. Fluctuation in activity appeared to follow a 13-week cycle. Meteorological effects on activity were studied during 2 weeks of peak tabanid abundance. Temperature, humidity, and wind accounted for 89% of the variation observed during the 23 weeks. Activity of this species observed on a particular day appeared to be the result of the overall population level and meteorological conditions at the time.

Animals↗
PubMedDate not supplied

Comparative evaluation of four serodiagnostic tests for scrub typhus in Thailand.

The commercial dot-blot enzyme-linked immunosorbent assay Dip-S-Ticks dipstick test was compared with the indirect immunoperoxidase (IIP) and Weil-Felix (WF) tests for the diagnosis of scrub typhus, using the indirect immunofluorescent antibody test (IFA) as the reference standard. With a panel of 117 positive and 75 negative sera, the dipstick test was 94% sensitive and 98.7% specific at a cut-off value of one or more positive dots. The IIP was 90.6% sensitive and 100% specific at a cut-off titre of 1:400, and was more sensitive than the IFA with acute sera (79.6% vs. 68.5% at a titre > or = 1:400). All 3 were superior to the WF, which lacked sensitivity. The dipstick assay was easy to perform and did not require sophisticated electrical equipment, and the results were available within one hour. It is therefore suitable for use in rural Thailand, where scrub typhus is common.

Agglutination Tests↗
PubMedDate not supplied

Reemergence of Plasmodium vivax malaria in the republic of Korea.

Plasmodium vivax malaria reemerged in the Republic of Korea in 1993. The number of cases has tripled each year since, with more than 1,600 cases reported in 1997. All 27 cases in U.S. troops resolved uneventfully with chloroquine/primaquine therapy. Disease is localized along the western Demilitarized Zone and presents minimal risk to tourists.

Antimalarials↗
PubMedDate not supplied

Distribution of dengue and Japanese encephalitis among children in rural and suburban Thai villages.

In the rainy season of 1989, IgG and IgM antibodies against dengue and Japanese encephalitis viruses (measured by enzyme-linked immunoassay [ELISA]) in serum from all primary-school children in two areas of central Thailand were sampled in order to choose a study site for more detailed epidemiological and entomological analysis. Students in three schools in the largely non-agricultural, suburban community of Bang Bua Thong, Nontaburi Province were sampled in late June and July. Of 1,477 children, 33/1,000 had recent dengue infection and 7/1,000 had recent JE infection. The rate of dengue infection in each village influenced the rate in schools, in that the rate of the school could be predicted from the proportion of students coming from each village. This result suggested that most transmission occurred in the residential environment; otherwise, the rate in each village going to a single school would be identical. Serum samples were taken in late August in the agricultural community of Hua Samrong, Chachoengsao Province. Of 748 students in two schools, 95/1,000 had signs of recent dengue infection and 32/1,000 had signs of recent JE infection. Two of 12 villages had significantly less flavivirus infection than some other villages and three villages had significantly more flavivirus infection. The children from one village had a dengue infection rate of 256 per 1,000, which was higher than the national average for the worst year (1987) previously recorded in Thailand. Within Hua Samrong, there was evidence for significant dengue transmission in one of the schools and concentrated transmission in small areas of two of the villages. The younger age group (3-8 years old) had significantly higher risk of infection by either flavivirus than older children. Elevated homes with wooden floors had significantly higher risk of dengue in the largest village. The observations from 1989 describe the epidemiological situation in rapidly developing, rural villages. This stage of development is probably being repeated throughout Southeast Asia as formerly isolated, rural villages become connected by transportation and economy to urban centers. What appears to be a single dengue outbreak based on passive surveillance conducted on a regional basis may actually be a variety of epidemiological situations. The practical implication of this conclusion is that application of a combination of vaccination and vector control should be targeted to higher risk areas in order to increase the likelihood of regional dengue virus eradication.

Adolescent↗