Wolbachia strain wMelPop reduces longevity of its Drosophila melanogaster host and halves lifespan when introduced into the mosquito Aedes aegypti. We show that wMelPop induces upregulation of the mosquito innate immune system and that its presence inhibits the development of filarial nematodes in the mosquito. These data suggest that wMelPop could be used in the global effort to eliminate lymphatic filariasis, and possibly the control of other mosquito-borne parasites where immune preactivation inhibits their development. The cost of constitutive immune upregulation may contribute to the life-shortening phenotype.Wolbachia pipientis is a maternally inherited intracellular bacterium of invertebrates, capable of spreading itself through populations by reproductive manipulation such as cytoplasmic incompatibility (CI). The strain wMelPop or 'popcorn', unusually, reduces longevity of its Drosophila melanogaster host (1) and has been shown to also halve lifespan when the mosquito Aedes aegypti was stably transinfected (2). The wMelPop life-shortening phenotype offers the prospect of a novel disease control system by potentially skewing the population structure toward younger individuals. Vectorial capacity is particularly sensitive to mosquito age because mosquito-borne pathogens require an extrinsic incubation period between ingestion and transmission that is long compared to mean lifespan in the field, such that only older mosquitoes within a population are potentially infective. wMelPop was also found to be inherited at high rates and to induce strong cytoplasmic incompatibility (CI) in Ae. aegypti, providing a reproductive advantage to infected females. The wMelPop strain should be capable of spread through populations despite the reduction in mean lifespan, because the reproduction of older individuals makes a relatively small contribution to the next generation (2-6).We compared host gene expression using whole genome microarrays in genetically identical Ae. aegypti lines infected and uninfected with wMelPop (7) to examine the mechanism underlying the life-shortening phenotype. Of 199 gene transcripts upregulated by more than a twofold threshold, 78 had putative immune-related functions (Fig. 1, table S2). These included genes that encode seventeen CLIP domain serine proteases, nine FREPs (fibrinogen-related proteins), six cecropins, four TEPs (Thio-ester containing proteins), three defensins, three PPOs (prophenoloxidases), two lysozymes, two PGRPs (peptidoglycan recognition proteins), two GNBPs (Gram negative binding proteins), and the NF-κB transcription factor Rel2. At higher levels of fold upregulation, effector genes, particularly cecropins and other antimicrobial peptides, dominate the list (Fig. 1, table S2). Five immune-related genes (primarily of regulatory predicted function) were downregulated below the twofold threshold (table S2).* To whom correspondence should be addressed. steven.sinkins@zoo.ox.ac.uk. Quantitative RT-PCR (qRT-PCR) experiments, with mosquitoes at two and fifteen days pos...

Background: Reduction or elimination of vector populations will tend to reduce or eliminate transmission of vector-borne diseases. One potential method for environmentally-friendly, species-specific population control is the Sterile Insect Technique (SIT). SIT has not been widely used against insect disease vectors such as mosquitoes, in part because of various practical difficulties in rearing, sterilization and distribution. Additionally, vector populations with strong density-dependent effects will tend to be resistant to SIT-based control as the population-reducing effect of induced sterility will tend to be offset by reduced density-dependent mortality.

Dengue and dengue hemorrhagic fever are increasing public health problems with an estimated 50–100 million new infections each year. Aedes aegypti is the major vector of dengue viruses in its range and control of this mosquito would reduce significantly human morbidity and mortality. Present mosquito control methods are not sufficiently effective and new approaches are needed urgently. A “sterile-male-release” strategy based on the release of mosquitoes carrying a conditional dominant lethal gene is an attractive new control methodology. Transgenic strains of Aedes aegypti were engineered to have a repressible female-specific flightless phenotype using either two separate transgenes or a single transgene, based on the use of a female-specific indirect flight muscle promoter from the Aedes aegypti Actin-4 gene. These strains eliminate the need for sterilization by irradiation, permit male-only release (“genetic sexing”), and enable the release of eggs instead of adults. Furthermore, these strains are expected to facilitate area-wide control or elimination of dengue if adopted as part of an integrated pest management strategy.

Mosquitoes (Diptera: Culicidae) of the Anopheles (Cellia) Myzomyia Series are important malaria vectors in Africa, India and Southeast Asia. Among 10 named species of Myzomyia known from the Oriental Region, seven form the An. minimus group. Even for expert taxonomists, the adults of these species remain difficult to identify morphologically. For technical staff of malaria control programmes, confusion may extend to misidentification of species that are not formally within the minimus group. For identification of specimens from Indochina (Cambodia, Laos, Vietnam), we describe a multiplex polymerase chain reaction (PCR) assay, based on rDNA internal transcribed spacer 2 (ITS2) sequences, that employs a cocktail of primers to identify An. minimus Theobald sibling species A and C (sensu; Green et al., 1990) and three other species in the An. minimus group (An. aconitus Dönitz, An. pampanai Büttiker & Beales, An. varuna Iyengar), as well as An. jeyporiensis James, also belonging to the Myzomyia Series. As the test is DNA-based, it can be applied to all life stages of these mosquitoes for ecological investigations and vector incrimination studies. This PCR assay is simpler, quicker, cheaper and more readily interpreted than previous assays.