We used a histologic technique to study multiple blood feeding in a single gonotrophic cycle by engorged Aedes aegypti (L.) that were collected weekly for 2 yr from houses in a rural village in Thailand (n = 1,891) and a residential section of San Juan, Puerto Rico (n = 1,675). Overall, mosquitoes from Thailand contained significantly more multiple meals (n = 1,300, 42% double meals, 5% triple meals) than mosquitoes collected in Puerto Rico (n = 1,156, 32% double meals, 2% triple meals). The portion of specimens for which frequency of feeding could not be determined was 31% at both sites. We estimated that on average Ae. aegypti take 0.76 and 0.63 human blood meals per day in Thailand and Puerto Rico, respectively. However, frequency of multiple feeding varied among houses and, in Puerto Rico, the neighborhoods from which mosquitoes were collected. In Thailand 65% of the mosquitoes fed twice on the same day, whereas in Puerto Rico 57% took multiple meals separated by> or = 1 d. At both sites, the majority of engorged specimens were collected inside houses (Thailand 86%, Puerto Rico 95%). The number of blood meals detected was independent of where mosquitoes were collected (inside versus outside of the house) at both sites and the time of day collections were made in Puerto Rico. Feeding rates were slightly higher for mosquitoes collected in the afternoon in Thailand. Temperatures were significantly higher and mosquitoes significantly smaller in Thailand than in Puerto Rico. At both sites female size was negatively associated with temperature. Rates of multiple feeding were associated positively with temperature and negatively with mosquito size in Thailand, but not in Puerto Rico. Multiple feeding during a single gonotrophic cycle is a regular part of Ae. aegypti biology, can vary geographically and under different climate conditions, and may be associated with variation in patterns of dengue virus transmission.

The tribe Aedini (Family Culicidae) contains approximately one-quarter of the known species of mosquitoes, including vectors of deadly or debilitating disease agents. This tribe contains the genus Aedes, which is one of the three most familiar genera of mosquitoes. During the past decade, Aedini has been the focus of a series of extensive morphology-based phylogenetic studies published by Reinert, Harbach, and Kitching (RH&K). Those authors created 74 new, elevated or resurrected genera from what had been the single genus Aedes, almost tripling the number of genera in the entire family Culicidae. The proposed classification is based on subjective assessments of the “number and nature of the characters that support the branches” subtending particular monophyletic groups in the results of cladistic analyses of a large set of morphological characters of representative species. To gauge the stability of RH&K’s generic groupings we reanalyzed their data with unweighted parsimony jackknife and maximum-parsimony analyses, with and without ordering 14 of the characters as in RH&K. We found that their phylogeny was largely weakly supported and their taxonomic rankings failed priority and other useful taxon-naming criteria. Consequently, we propose simplified aedine generic designations that 1) restore a classification system that is useful for the operational community; 2) enhance the ability of taxonomists to accurately place new species into genera; 3) maintain the progress toward a natural classification based on monophyletic groups of species; and 4) correct the current classification system that is subject to instability as new species are described and existing species more thoroughly defined. We do not challenge the phylogenetic hypotheses generated by the above-mentioned series of morphological studies. However, we reduce the ranks of the genera and subgenera of RH&K to subgenera or informal species groups, respectively, to preserve stability as new data become available.

Aspiration collections of adult Aedes aegypti (L.) were made weekly from inside and outside of houses for 3 yr in a rural Thai village (n = 9,637 females and n = 11,988 males) and for 2 yr in a residential section of San Juan, Puerto Rico (n = 5,941 females and n = 6,739 males). In Thailand, temperature and rainfall fell into distinct seasonal categories, but only temperature was correlated with fluctuations in female abundance. Average weekly temperature 6 wk before mosquitoes were collected and minimum weekly temperature during the week of collection provided the highest correlations with female abundance. Accounting for annual variation significantly improved Thai models of temperature and mosquito abundance. In Puerto Rico, temperature, but not rainfall, could be categorized into seasonal patterns. Neither was correlated with changes in female abundance. At both sites the vast majority of females were collected inside houses and most contained a blood meal. Most teneral females were collected outside. Wing length--an indicator of female size--and parity, egg development or engorgement status were not correlated, indicating that feeding success and survival were not influenced by female size. At both sites, females fed almost exclusively on human hosts (> or = 96%), a pattern that did not change seasonally. In Puerto Rico more nonhuman blood meals were detected in mosquitoes collected outside than inside houses; no such difference was detected in Thailand. Gut contents of dissected females indicated that females in the Thai population had a younger age distribution and fed more frequently on blood than did Ae. aegypti in Puerto Rico. Our results indicated that aspects of this species' biology can vary significantly from one location to another and 1 yr to the next.

Morbidity and mortality caused by rickettsioses have had a major influence on military activities and public health for >2000 years. The threat posed by the rickettsioses is reviewed, focusing on the impact and epidemiology of those that have adversely influenced wartime operations and the current challenges posed by these diseases. With their uneven worldwide distribution, the discovery of drug-refractory strains of Orientia tsutsugamushi, the increased threat of their use in acts of bioterrorism, frequent deployment of troops to regions of endemicity, and exposures due to increased humanitarian missions, these diseases continue to be a threat to military personnel in the field. Effective strategies to reduce the impact of these diseases include development of effective vaccines, enhanced surveillance, and development of new safe, effective, and odorless repellants. The continuation of a proven, highly productive military infectious disease research program is essential for providing solutions to these daunting tasks.

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BACKGROUND: Aedes (Stegomyia) albopictus (Skuse) is an important disease vector and biting nuisance. During the 2009 active season, six ∼1000-parcel sites were studied, three in urban and three in suburban areas of New Jersey, United States, to examine the efficacy of standard integrated urban mosquito control strategies applied area wide. Active source reduction, larviciding, adulticiding and public education (source reduction through education) were implemented in one site in each county, an education-only approach was developed in a second site and a third site was used as an untreated experimental control. Populations were surveyed weekly with BG-Sentinel traps and ovitraps.RESULTS: A substantial reduction in Ae. albopictus populations was achieved in urban sites, but only modest reductions in suburban sites. Education alone achieved significant reductions in urban adult Ae. albopictus. Egg catches echoed adult catches only in suburban sites.CONCLUSIONS: There are significant socioeconomic and climatic differences between urban and suburban sites that impact upon Ae. albopictus populations and the efficacy of the control methods tested. An integrated pest management approach can affect abundances, but labor-intensive, costly source reduction was not enough to maintain Ae. albopictus counts below a nuisance threshold. Nighttime adult population suppression using truck-mounted adulticides can be effective. Area-wide cost-effective strategies are necessary. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

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Aedes aegypti (L.) were collected by aspiration once each week from in and around houses in a rural village in Chachoengsao Province. Thailand, during May 1990 to June 1991. Of the 1,230 specimens analyzed with a sandwich ELISA, 73% reacted to one or more of the seven hosts which we tested. Eighty-eight percent (789/896) of all detectable meals were identified as being from a single host (human). Patent multiple meals (double and triple), of which one was always human, were detected in 7% (66/896) of the specimens. The probability of feeding on a human, either as a single host or in a patent mixed meal, was > 0.90 during 12 of the 14 mo of the study; this probability never dropped below 0.85. The probability of Ae. aegypti taking multiple blood meals during a single gonotrophic cycle varied widely from 0.0 to 1.0. The possibility is discussed, including epidemiological significance, that there are seasonal fluctuations in the frequency of multiple feeding by Ae. aegypti and that multiple feeding increases in concert with seasonal trends for dengue infections of humans in Thailand.