A morphometric and molecular study of adult male and female Lutzomyia shannoni (Dyar 1929) collected at seven different locations within the southeastern United States was conducted to assess the degree of divergence between the grouped specimens from each location. The collection locations were as follows: Fort Bragg, NC; Fort Campbell, KY; Fort Rucker, AL; Ossabaw Island, GA; Patuxent National Wildlife Research Refuge, MD; Suwannee National Wildlife Refuge, FL; and Baton Rouge, LA. Forty males and forty females from each location were analyzed morphometrically from 54 and 49 character measurements, respectively. In addition, the molecular markers consisting of the partial cytochrome c oxidase subunit I (from 105 sand flies: 15 specimens/collection site) and the partial internal transcribed spacer 2 (from 42 sand flies: six specimens/collection site) were compared. Multivariate analyses indicate that the low degree of variation between the grouped specimens from each collection site prevents the separation of any collection site into an entity that could be interpreted as a distinct population. The molecular analyses were in concordance with the morphometric study as no collection location grouped into a separate population based on the two partial markers. The grouped specimens from each collection site appear to be within the normal variance of the species, indicating a single population in the southeast United States. It is recommended that additional character analyses of L. shannoni based on more molecular markers, behavioral, ecological, and physiological characteristics, be conducted before ruling out the possibility of populations or a cryptic species complex within the southeastern United States.
This report describes two male specimens of the sand fly species Lutzomyia shannoni (Dyar) (Diptera: Psychodidae: Phlebotominae) collected at Fort Rucker, AL, and Fort Campbell, KY, in dry ice-baited light traps during September 2005. The specimens were observed to have anomalies to the number of spines on the gonostyli. The taxonomic keys of Young and Perkins (Mosq. News 44: 263-285; 1984) use the number of spines on the gonostylus in the first couplet to differentiate two major groupings of North American sand flies. The two anomalous specimens were identified as L. shannoni based on the following criteria: (1) both specimens possess antennal ascoids with long, distinct proximal spurs (a near diagnostic character of L. shannoni in North America), (2) the sequences of the partial cytochrome c oxidase subunit 1 gene from both specimens indicated L. shannoni, and (3) the sequences of the internal transcribed spacer 2 molecular marker from both specimens indicated L. shannoni. The anomalous features are fundamentally different from each other as the Fort Rucker specimen possesses a fifth spine (basally located) on just one gonostylus, whereas the Fort Campbell specimen possesses five spines (extra spines subterminally located) on both gonostyli. Because the gonostyli are part of the external male genitalia, anomalies in the number of spines on the gonostyli may have serious biological consequences, such as reduced reproductive success, for the possessors. These anomalies are of taxonomic interest as the specimens could easily have been misidentified using available morphological keys.
The seasonal abundance and temporal patterns of the adult sand fly (Lutzomyia shannoni Dyar) were examined at the Patuxent National Wildlife Research Refuge, MD, from August 3, 2005, to July 29, 2006. A total of 138 (53 males, 85 females) L. shannoni was collected from 4 dry ice-baited traps set at the same 4 locations throughout the study. The male: female ratio was 1: 2.4. All 4 traps, separated by a maximum distance of approximately 1.6 km, operated simultaneously on the collection dates. The collection dates were spaced apart by near weekly intervals during the months of expected sand fly activity. No collections occurred in December-February. August was clearly the period of peak adult abundance as the numbers collected were significantly greater during this month than any other month of collection. Results indicate the existence of a unimodal pattern of abundance with adult emergence beginning in June and ending by September. The temporal pattern and abundance differ from what has been observed for the species on Ossabaw Island, a barrier island located along coastal Georgia, and at San Felasco Hammock Preserve State Park, Gainesville, FL. Continued research is needed to compile multiyear data to confirm the temporal abundance patterns of this species in Maryland.
BACKGROUND:Nearly 1300 cases of leishmaniasis have been identified in American military personnel deployed to Iraq and Afghanistan. The symptoms of this disease can range from a mild, self-limiting cutaneous infection to a deadly visceral infection and are not prevented by chemoprophylaxis or immunization. Effective treatments, however, are available. The disease-causing parasite is spread through the bite of the female sand fly. Although the disease occurs in both the Old World and the New World, the parasite species differ between the hemispheres. The large number of cases in military veterans has caused some concern that Old World, temperate-adapted parasite species could be introduced into the native sand fly populations of American military facilities where veterans of the current conflicts return following their deployments. This paper reports part of a larger study to analyze the risk of such an accidental importation. Four potential habitats on two large Army facilities in the Southeast United States were surveyed to determine relative sand fly density. The National Land Cover Map was used to provide sand fly density prediction maps by habitat.RESULTS:Sand fly density was significantly higher in deciduous forest and even higher at the interface between forest and open grassland. The evergreen forest and agricultural fields supported very low densities. On Fort Campbell, KY, the percentage of land covered by suitable habitat was very high. A sand fly density prediction map identified large tracts of land where infected individuals would be at higher risk of exposure to sand fly bites, resulting in an increased risk of introducing the parasite to a native insect population. On Fort Bragg, NC, however, commercial farming of long leaf pine reduced the percentage of the land covered in vegetation suitable for the support of sand flies. The risk of introducing an exotic Leishmania spp. on Fort Bragg, therefore, is considered to be much lower than on Fort Campbell.CONCLUSION:A readily available land cover product can be used at the regional level to identify areas of sand fly habitat where human populations may be at higher risk of exposure. The sand fly density prediction maps can be used to direct further surveillance, insect control, or additional patient monitoring of potentially infected soldiers.
We assessed the prophylactic efficacy of azithromycin (250 mg/day) against malaria in 276 adults in western Thailand in a randomized, double-blind, placebo-controlled trial. After antimalarial suppressive treatment, volunteers were randomized in a 2:1 ratio to either the azithromycin or placebo, respectively. Study medication was given for an average of 74 days. The azithromycin group (n = 179) had five endpoint parasitemias (1 Plasmodium vivax and 4 P. falciparum), and the placebo group (n = 97) had 28 endpoint parasitemias (21 P. vivax, 5 P. falciparum, and 2 mixed infections). Adverse events and compliance and withdrawal rates were similar in both groups. The protective efficacy (PE) of azithromycin was 98% for P. vivax (95% confidence interval [CI] = 88-100%). There were too few cases to reliably estimate the efficacy of azithromycin for P. falciparum (PE = 71%, 95% C = -14-94%). We conclude that daily azithromycin was safe, well-tolerated, and had a high efficacy for the prevention of P. vivax malaria.
OBJECTIVES—Current incidence trends in type 2 diabetes portend a significant public health burden and have largely been attributed to similar trends in overweight and physical inactivity. Medical surveillance of the U.S. military indicates that the incidence of all types of diabetes is similar to that in the civilian population (1.9 vs. 1.6 cases per 1,000 person-years) despite weight and fitness standards. Differences in the common determinants of diabetes have not been studied in the military population, which may provide novel clues to the increasing incidence of diabetes in the U.S. RESEARCH DESIGN AND METHODS—A case-control study, 4-to-1 matched for age, sex, entry date, time in service, and service component (e.g., Army, Navy), was used to describe the association of race/ethnicity, socioeconomic status, and BMI and blood pressure at entry into military service with the subsequent development of type 2 diabetes. RESULTS—Increased BMI (adjusted odds ratio, 3.0 for the ≥30 kg/m2 vs. ≤20 kg/m2 categories and 2.0 for the 25.0–29.9 kg/m2 category, compared with the reference category), African-American (adjusted odds ratio, 2.0) and Hispanic origin (adjusted odds ratio, 1.6) compared with white race and rank (adjusted odds ratio for junior enlisted versus officers, 4.1) were all associated with type 2 diabetes. CONCLUSIONS—Individuals with type 2 diabetes in the U.S. military have risk factors similar to the general U.S. population. Because diabetes is a preventable disease, it is of concern that it is occurring in this population of younger and presumably more fit individuals. This has significant implications for the prevention of diabetes in both military and civilian populations.
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.