Craig A. Stoops

Remotely-sensed land use patterns and the presence of Anopheles larvae (Diptera: Culicidae) in Sukabumi, West Java, Indonesia

ABSTRACT Land use patterns and the occurrence of Anopheles species larvae were studied in Sukabumi District, West Java, Indonesia, from October 2004 to September 2005. Two land use maps derived using remote sensing were used. One map derived from Quickbird satellite images of 150 km2 of the Simpenan and Ciemas subdistricts (106° 27′53″–106° 38′38″ E and 6° 59′59″–7° 8′46″ S) in Sukabumi and one using ASTER images covering 4,000 km2 of Sukabumi District from 106° 22′15″–107° 4′1″ E and 6° 42′50″–7° 26′13″ S. There was a total of 11 Anopheles spp. collected from 209 sampling locations in the area covered by the Quickbird image and a total of 15 Anopheles spp. collected from 1,600 sampling locations in the area covered by the ASTER map. For the area covered by the land use maps, ten species were found to have statistically positive relationships between land use class and species presence: Anopheles aconitus, An. annularis, An. barbirostris. An. flavirostris, An. insulaeflorum, An. kochi, An. maculatus, An. subpictus, An. sundaicus, and An. vagus. Quickbird and ASTER satellite images both produced land maps that were adequate for predicting species presence in an area. The land use classes associated with malaria vector breeding were rice paddy (An. aconitus, An. subpictus), plantation located near or adjacent to human settlements (An. maculatus), bush/shrub (An. aconitus, An. maculatus, An. sundaicus), bare land, and water body land use on the coast located ≤ 250 m of the beach (An. sundaicus). Understanding the associations of habitat and species in one area, predictions of species presence or absence can be made prior to a ground survey allowing for accurate vector survey and control planning.

Environmental Factors Associated with Spatial and Temporal Distribution of Anopheles (Diptera: Culicidae) Larvae in Sukabumi, West Java, Indonesia

Abstract A 12-mo ecological study of the spatial-temporal distribution of immature stages of Anopheles species was conducted in Sukabumi District, West Java, Indonesia. The study characterized 1,600 sites from a contiguous coastal and hill zone (0–800-m elevation) of which 64% contained Anopheles larvae. Principal component and multiple logistic regression analyses identified ecological parameters associated with presence of nine [Anopheles aconitus Doenitz, Anopheles annularis Van de Wulp, Anopheles barbirostris Van der Wulp, Anopheles flavirostris (Ludlow), Anopheles insulaeflorum (Swellengrebel and Swellengrebel de Graaf), Anopheles kochi Doenitz, Anopheles maculatus Theobald, Anopheles sundaicus (Rodenwaldt), and Anopheles vagus Doenitz] of 15 Anopheles species collected. Combined data for all nine species showed increased Anopheles presence associated with wet season periods and higher elevation habitats exhibiting reduced tree canopy coverage, higher water temperatures, and shallower water depths. Habitat variables measured included topography (elevation), water conditions (temperature, pH, salinity depth, and velocity), habitat characteristics (substrate and canopy cover), density and type of aquatic vegetation coverage (riparian, floating, and emergent), and distance from nearest human habitation. Significant relationships were found for nine species when using all habitats in the analysis. Habitat characteristics for three species were refined. An. aconitus and An. barbirostris were associated with higher elevation rice, Oryza savita L., paddies with relatively shallow water depths, higher water temperatures, higher acidity and salinity concentrations, and a greater average distance from human habitation. An. vagus presence in rice paddies was associated with lower elevation fields, deeper and cooler water, less acidic and saline conditions, and habitats closer to human dwellings. Overall, the distribution of Anopheles species in Sukabumi was found to be nonrandom and predictable on the basis of habitat characteristics.

Bionomics of Anopheles spp. (Diptera: Culicidae) in a Malaria Endemic Region of Sukabumi, West Java, Indonesia

ABSTRACT: A 15-month bionomic study of Anopheles species was conducted in two ecologically distinct villages (coastal and upland) of Sukabumi District, West Java, Indonesia from June 2006 to September 2007. Mosquitoes were captured using human-landing collections at both sites. During the study, a total of 17,100 Anopheles mosquitoes comprising 13 Anopheles species were caught: 9,151 at the coastal site and 7,949 at the upland site. Anopheles barbirostris, Anopheles maculatus, and Anopheles vagus were the predominant species caught at the coastal site, and Anopheles aconitus, Anopheles barbirostris, and An. maculatus predominated in the upland site. Overall, species were exophagic at both sites, but there was variation between species. Anopheles aconitus was endophagic at the coastal site, exophagic at the upland site, collected most often in April 2007 and had a peak landing time between 22:00 and 23:00. Anopheles sundaicus was only collected at the coastal site, exophagic, collected most often in October 2006, and had a peak landing time between 19:00 and 20:00. Potential malaria vector species such An. aconitus, An. maculatus, and An. sundaicus were present throughout the year. None of the 7,770 Anopheles tested using CSP-ELISA were positive for malaria, although the risk for malaria outbreaks in Sukabumi district remains high.

Laboratory and field testing of bednet traps for mosquito (Diptera: Culicidae) sampling in West Java, Indonesia

ABSTRACT: Surveillance of medically important mosquitoes is critical to determine the risk of mosquito-borne disease transmission. The purpose of this research was to test self-supporting, exposure-free bednet traps to survey mosquitoes. In the laboratory we tested human-baited and unbaited CDC light trap/cot bednet (CDCBN) combinations against three types of traps: the Mbita Trap (MIBITA), a Tent Trap (TENT), and a modified Townes style Malaise trap (TSM). In the laboratory, 16 runs comparing MBITA, TSM, and TENT to the CDCBN were conducted for a total of 48 runs of the experiment using 13,600 mosquitoes. The TENT trap collected significantly more mosquitoes than the CDCBN. The CDCBN collected significantly more than the MBITA and there was no difference between the TSM and the CDCBN. Two field trials were conducted in Cibuntu, Sukabumi, West Java, Indonesia. The first test compared human-baited and unbaited CDCBN, TENT, and TSM traps during six nights over two consecutive weeks per month from January, 2007 to September, 2007 for a total of 54 trapnights. A total of 8,474 mosquitoes representing 33 species were collected using the six trapping methods. The TENT-baited trap collected significantly more mosquitoes than both the CDCBN and the TSM. The second field trial was a comparison of the baited and unbaited TENT and CDCBN traps and Human Landing Collections (HLCs). The trial was carried out from January, 2008 to May, 2008 for a total of 30 trap nights. A total of 11,923 mosquitoes were collected representing 24 species. Human Landing Collections captured significantly more mosquitoes than either the TENT or the CDCBN. The baited and unbaited TENT collected significantly more mosquitoes than the CDCBN. The TENT trap was found to be an effective, light-weight substitute for the CDC light-trap, bednet combination in the field and should be considered for use in surveys of mosquito-borne diseases such as malaria, arboviruses, and filariasis.

Larval collection records of Culex species (Diptera: Culicidae) with an emphasis on Japanese encephalitis vectors in rice fields in Sukabumi, West Java, Indonesia

(Leicester), Culex mimeticus Noe, Culex nigropunctatus Edwards, Culex pallidothorax Theo., Culex pseudosinensis Colless, Culex pseudovishnui, Culex rubithoracis (Leicester), Culex tritaeniorhynchus, Culex sinensis Theo., Culex sitiens Weid., Culex vishnui, and Culex whitmorei (Giles). The collection of Cx. mimeticus and Cx. pseudiosinensis represents the first Indonesian records of these species. Voucher specimens are located in the U.S. Naval Medical Research Unit 2 laboratory and will be made available for further study in conjunction with the Indonesian Ministry of Health. Because of their potential importance in JE transmission, the collection records for the following species will be provided: Cx. fuscocephala, Cx. gelidus, Cx. pseudovishnui, Cx. tritaeniorhynchus, and Cx. vishnui.

Feeding behavior of larval black flies (Diptera: Simuliidae) with and without exposure to Bacillus thuringiensis var. israelensis

ABSTRACT Behavioral time budgets were constructed for larval black flies of the Simulium jenningsi and S. tuberosum groups in a recirculating flume. Larvae spent the majority (54–80%) of time filter feeding. Flick rates of the labral fans, which averaged 0.7–1.9 flicks/sec, did not differ significantly between regimens of 0 mg/l and 10 mg/l of food. Larvae consistently flicked the fan nearest the water surface significantly more often than the lower fan. They also tended to flick the right fan more than the left, although this trend was significant in only one of four treatments. Although handedness cannot be dismissed, the differential flick rate appeared to be related to the position of the fans relative to the water surface, possibly because of different particulate concentrations in the microcurrents received by the upper and lower fans. Cessation of feeding by larvae of the S. jenningsi group from rivers regularly treated with Bacillus thuringiensis var. israelensis was independent of exposure to this biological control agent. Of larvae that ceased to feed, the mean time to cessation of feeding after exposure to Bti was 12–18 s, sufficient time to ingest a lethal dose.

Comparison of BG-Sentinel® Trap and Oviposition Cups for Aedes aegypti and Aedes albopictus Surveillance in Jacksonville, Florida, USA

Abstract The BG-Sentinel® (BGS) trap and oviposition cups (OCs) have both proven effective in the surveillance of Aedes species. This study aimed to determine which of the 2 traps could best characterize the relative population sizes of Aedes albopictus and Aedes aegypti in an urban section of Jacksonville, FL. Until 1986, Ae. aegypti was considered the dominant container-breeding species in urban northeastern Florida. Since the introduction of Ae. albopictus, Ae. aegypti has become almost completely extirpated. In 2011, a resurgence of Ae. aegypti was detected in the urban areas of Jacksonville; thus this study initially set out to determine the extent of Ae. aegypti reintroduction to the area. We determined that the BGS captured a greater number of adult Ae. aegypti than Ae. albopictus, while OCs did not monitor significantly different numbers of either species, even in areas where the BGS traps suggested a predominance of one species over the other. Both traps were effective at detecting Aedes spp.; however, the BGS proved more diverse by detecting over 20 other species as well. Our results show that in order to accurately determine vectorborne disease threats and the impact of control operations on these 2 species, multiple trapping techniques should be utilized when studying Ae. aegypti and Ae. albopictus population dynamics.

Suppression of Amblyomma americanum (Ixodida: Ixodidae) for Short-Term Field Operations Utilizing Cypermethrin and Lambda-Cyhalothrin

ABSTRACT Tick-borne diseases pose significant risks to U.S. military personnel who conduct operations, both domestic and abroad. To determine the feasibility of protecting personnel from tick vectors during short-term field deployments, acaricides Cypermethrin (Demon WP, Syngenta, Greensboro, NC) and lambda-cyhalothrin (Surrender Pestabs, CSI, Pasadena, TX) were applied to plots within two separate field sites on Camp Blanding Joint Training Center in Starke, FL, from May to June 2011. We analyzed their effectiveness in reducing tick counts for 6 wk after application. In total, 8,193 ticks were identified and counted, of which >99% were a mix of nymphs and adult-stage Amblyomma americanum (L.). Our results indicate that both Cypermethrin and lambda-cyhalothrin were effective in significantly reducing tick numbers and preventing entry into treated plots for 6 wk after application. Thus, these two acaracides can be used to effectively suppress tick populations and provide residual protection in small geographic areas of recreation or public health significance.

SR450 and Superhawk XP Applications of Bacillus Thuringiensis Israelensis Against Culex Quinquefasciatus

Abstract Sprayer comparisons and larval morality assays were conducted following SR450 backpack mist blower and Superhawk XP thermal fogger applications of Vectobac® WDG Bacillus thuringiensis israelensis (Bti) against Culex quinquefasciatus. Bacillus thuringiensis israelensis was applied at maximum label rate in a 232.26-m2 field plot located in north-central Florida with containers placed at 2 heights (ground level and 1.52 m above ground) on stakes positioned 3.04, 6.09, 9.14, 12.19, and 15.24 m from the spray line. Results indicated that there was no significant (P > 0.05) difference in 24- and 48-h larval mortality between the 2 sprayers or between the 2 heights. There was significant difference (P < 0.05) among the 5 rows, with mortality continuously decreasing with increasing distance from sprayer. Both sprayers provided on average >70% larval mortality 3.04–9.14 m from the spray line, and <60% mortality at 12.19 and 15.24 m. The data suggest that the SR450 and Superhawk XP may be comparable sprayers for use with Bti to control mosquito larvae.

Sand Fly Surveillance and Control on Camp Ramadi, Iraq, as Part of a Leishmaniasis Control Program

Abstract : Vector-borne diseases are a serious health threat to U.S. troops stationed around the world. U.S. forces deployed to Iraq following the 2003 invasion experienced serious risk of infection by several vector-borne pathogens, specifically cutaneous (CL) and visceral leishmaniasis (VL) (Aliaga and Aronson 2007). Camp Ramadi, a U.S. military Forward Operating Base, was established in 2003 at the Al Anbar provincial capital of Ramadi, approximately 110 km west of Baghdad. In Iraq the total number of cases of CL reported per year from 2004 to 2008 was 1,655 and for VL was 1,711 (Alvar et al. 2012). In Al Anbar province in 2008, the estimated incidence of CL and VL was 1 per 10,000 (Alvar et al. 2012). Because of the war, the number of cases of both CL and VL was most likely underreported in Al Anbar and all provinces of Iraq (Alvar et al. 2012). Because of the risk of vector-borne diseases, each large U.S. military facility, such as Camp Ramadi, had a vector control program operating throughout the year. As part of a base-wide vector control program, unbaited Center for Disease Control and Prevention (CDC) light traps were placed at three locations on Camp Ramadi between April and August, 2009 to gather baseline population estimates of adult sand flies and monitor the success of subsequent control measures. This paper reports sand fly collections over the five-month period, whether they were positive for Leishmania, and describes efforts to control sand fly populations using ultra-low volume (ULV) insecticide applications. Three sites on Camp Ramadi were established for trap placement in areas where U.S. troops worked and lived. Site one was in a grove of palm trees near troop living quarters and the base medical clinic. Site two was in a plot of scrub vegetation near the helicopter landing pad, and site three in tall vegetation near buildings occupied by the base Commander. All three sites had active rodent burrows.