Robert Burge

Correlation between Lethal Toxin-Neutralizing Antibody Titers and Protection from Intranasal Challenge with Bacillus anthracis Ames Strain Spores in Mice after Transcutaneous Immunization with Recombinant Anthrax Protective Antigen

ABSTRACT Transcutaneous immunization of mice with recombinant protective antigen (rPA) of Bacillus anthracis resulted in significantly higher lethal toxin-neutralizing antibody titers than did intramuscular injection of alum-adsorbed rPA. Immunized mice were partially protected against intranasal challenge with 235,000 (10 50% lethal doses) Ames strain B. anthracis spores. A highly significant correlation was observed between toxin-neutralizing antibody titer and survival after challenge. Future experiments with rabbits and nonhuman primates should confirm the significance of protection by this vaccine strategy.

A stable, oligosymptomatic malaria focus in Thailand

Blood from most of the 250 residents of a non-migratory farming village in south-eastern Thailand was visually examined for malaria parasites monthly for 2 years. Nearly 97% of the population had at least one (median = 5) patent Plasmodium falciparum infection per year; 72% had one due to P. vivax (median = 1). This contrasted with a slide positivity rate of 17% calculated from 12 months of passive case detection before the study began. Children 1-9 years old had the highest mean monthly prevalence (51%) and highest geometric mean density (10/500 white blood cells) of P. falciparum. Fewer than half the expected number of mixed infections were found but these were more common at high densities of P. falciparum. Individuals over 19 years old comprised 52% of the population but accounted for only 18% of P. vivax and 32% of P. falciparum gametocytaemias. Fever rates were marginally higher in those below 10 years old (8%) but occurred with equal frequency in those with patent infections or negative. The spleen rate (89% stage 1) was 24% in those under 15 years old and 7% in those older. No malaria mortality was seen P. falciparum cases treated for 10 d with quinine+tetracycline (QT) cleared the infection as often as those given one dose of mefloquine+sulfadoxine+pyrimethamine (MSP); both treatments reduced densities in cases not cured. Apparently unsupervised compliance was no better with MSP than with QT. The role played by hyperendemic, cryptic foci in Asian epidemics of malaria may have been underestimated.

Field Evaluation of Deet and a Piperidine Repellent Against Aedes communis (Diptera: Culicidae) and Simulium venustum (Diptera: Simuliidae) in the Adirondack Mountains of New York

Abstract Repellent efficacy of N,N-diethyl-3-methyl-benzamide (deet), the piperidine, 1-[3-cyclohexen-1-ylcarbonyl]-2-methylpiperidine (AI3-37220), and a 1:1 ratio of deet + AI3-37220 were evaluated topically (0.25 mg/cm2 applied in ethanol solution) on human volunteers against the mosquito Aedes communis (DeGeer) and the black fly Simulium venustum Say. The average repellency of all three formulations was >95% at 4 h. For both mosquitoes and black flies, deet alone provided <90% protection at 6 h, whereas AI3-37220 provided >95% protection. Although repellent treatments were not significantly different overall, the contrasts between AI3-3720 versus deet were significant at 6 and 8 h. The 95% confidence interval on percent repellency at 6 h ranged from 90.1 to 98.9% for AI3-37220 versus 64.3 to 82.2% for deet, and at 8 h ranged 76.1 to 88.5% for AI3-37220 versus 47.8 to 64.0% for deet. Similarly, the confidence interval for protection against black flies at 6 h by (AI3-37220 ranged from 86.3 to 99.5% and did not overlap with the confidence interval provided by deet alone (51.2 to 78.8%). There was no evidence of synergistic repellency from a combination of the two compounds; i.e., protection from combined compounds was no better than either repellent used alone.

Plasmodium falciparum andP. berghei: detection of sporozoites and the circumsporozoite proteins in the saliva ofAnopheles stephensi mosquitoes

Sporozoites and free circumsporozoite (CS) protein were stained immunoenzymatically in 1-min saliva samples collected fromAnopheles stephensi mosquitoes infected with eitherPlasmodium berghei orP. falciparum. The number of sporozoites in 1-min saliva-streak samples significantly increased as the salivary gland index rose from 3+ to 4+. ForP. berghei-infected mosquitoes from which saliva had been collected before 30 days postfeed, the median sporozoite counts for 3+ and 4+ gland indexes were 4.5 and 116, respectively. ForP. falciparum-infected mosquitoes, the median counts obtained in two experiments were 4.5 and 14.5 (3+) and 97 and 107 (4+), respectively. The frequency of sporozoite detection in the saliva of mosquitoes containing <100 salivary-gland sporozoites was low (0.1), whereas that in the saliva of mosquitoes with >100 sporozoites was high (0.96). In highly infected 4+P. berghei-infected mosquitoes from which saliva had been collected after 30 days postinfection, both the volume of saliva collected and the median number of sporozoites recovered decreased significantly.

Field-User Acceptability of New Camouflage Face Paint Formulations in the Republic of Korea

New formulations of camouflage face paint (CFP), one with 30% N,N-diethyl-3-methylbenzamide (DEET) and the other without DEET, were evaluated for soldier-user acceptability during a military field-training exercise in the Republic of Korea. Soldiers testing the CFP formulations were members of one of four U.S. Army infantry companies (A, B, C, or D). The formulations were evaluated while soldiers participated in simulated combat exercises for 5 days during hot, humid summer weather in Korea. Results showed that soldiers found both of the new formulations easier to apply (91.3% of respondents who used CFP without DEET and 87.9% of respondents who used CFP with DEET) and remove (82.6% without DEET and 81.2% with DEET) than the previous standard military-issue CFP. Soldier acceptability was higher for the new CFP formulation with 30% DEET (70.5%) than for the formulation without 30% DEET (52.9%). Soldiers recommended it more frequently (70.5%) than the formulation without 30% DEET (50.0%). The new CFP formulation with 30% DEET was rated more often (79.5%) as either good or excellent than the new formulation without 30% DEET (67.4%). Soldiers reported that the CFP formulation with 30% DEET more successfully camouflaged the face (92.7%) than the formulation without 30% DEET (80.0%).