登革Ⅱ型病毒经白纹伊蚊滞育卵的传递

采用C6/36细胞培养分离病毒的方法检测感染登革Ⅱ型病毒的白纹伊蚊Aedes albopictus滞育卵孵化的F₁代蚊虫感染率,从第一个生殖营养周期子代蚊虫中未分离到病毒,第二与第三生殖营养周期子代蚊虫最低感染率没有显著性差异（χ²=0.01,P＞0.0 5）,感染子代的批阳性率为9.1%,最低感染率为1∶330;间接免疫荧光检测结果表明感染登革Ⅱ型病毒的白纹伊蚊滞育卵孵化的子代成蚊能通过叮咬将登革病毒传播给敏感乳鼠。这些研究结果表明登革病毒能在媒介滞育卵内存活并传至子代,子代蚊虫能通过叮咬敏感宿主水平传播病毒。     

Aedes (Stegomyia) albopictus (Skuse): A Potential Vector of Zika Virus in Singapore

Background

Zika virus (ZIKV) is a little known arbovirus until it caused a major outbreak in the Pacific Island of Yap in 2007. Although the virus has a wide geographic distribution, most of the known vectors are sylvatic Aedes mosquitoes from Africa where the virus was first isolated. Presently, Ae. aegypti is the only known vector to transmit the virus outside the African continent, though Ae. albopictus has long been a suspected vector. Currently, Ae. albopictus has been shown capable of transmitting more than 20 arboviruses and its notoriety as an important vector came to light during the recent chikungunya pandemic. The vulnerability of Singapore to emerging infectious arboviruses has stimulated our interest to determine the competence of local Ae. albopictus to transmit ZIKV.

Methodology/Principal Findings

To determine the competence of Ae. albopictus to ZIKV, we orally infected local mosquito strains to a Ugandan strain virus. Fully engorged mosquitoes were maintained in an environmental chamber set at 29°C and 80–85%RH. Twelve mosquitoes were then sampled daily from day one to seven and on day 10 and 14 post infection (pi). Zika virus titre in the midgut and salivary glands of each mosquito were determined using tissue culture infectious dose₅₀ assay, while transmissibility of the virus was determined by detecting viral antigen in the mosquito saliva by qRT-PCR. High dissemination and transmission rate of ZIKV were observed. By day 7-pi, all mosquitoes have disseminated infection and 73% of these mosquitoes have ZIKV in their saliva. By day 10-pi, all mosquitoes were potentially infectious.

Conclusions/Significance

The study highlighted the potential of Ae. albopictus to transmit ZIKV and the possibility that the virus could be established locally. Nonetheless, the threat of ZIKV can be mitigated by existing dengue and chikungunya control program being implemented in Singapore.     

Impact of deltamethrin-resistance in Aedes albopictus on its fitness cost and vector competence

BackgroundAedes albopictus is one of the most invasive species in the world as well as the important vector for mosquito-borne diseases such as dengue fever, chikungunya fever and zika virus disease. Chemical control of mosquitoes is an effective method to control mosquito-borne diseases, however, the wide and improper application of insecticides for vector control has led to serious resistance problems. At present, there have been many reports on the resistance to pyrethroid insecticides in vector mosquitoes including deltamethrin to Aedes albopictus. However, the fitness cost and vector competence of deltamethrin resistant Aedes albopictus remain unknown. To understand the impact of insecticide resistant mosquito is of great significance for the prevention and control mosquitoes and mosquito-borne diseases.Methodology/Principal findingsA laboratory resistant strain (Lab-R) of Aedes albopictus was established by deltamethrin insecticide selecting from the laboratory susceptible strain (Lab-S). The life table between the two strains were comparatively analyzed. The average development time of Lab-R and Lab-S in larvae was 9.7 days and 8.2 days (P < 0.005), and in pupae was 2.0 days and 1.8 days respectively (P > 0.05), indicating that deltamethrin resistance prolongs the larval development time of resistant mosquitoes. The average survival time of resistant adults was significantly shorter than that of susceptible adults, while the body weight of resistant female adults was significantly higher than that of the susceptible females. We also compared the vector competence for dengue virus type-2 (DENV-2) between the two strains via RT-qPCR. Considering the results of infection rate (IR) and virus load, there was no difference between the two strains during the early period of infection (4, 7, 10 day post infection (dpi)). However, in the later period of infection (14 dpi), IR and virus load in heads, salivary glands and ovaries of the resistant mosquitoes were significantly lower than those of the susceptible strain (IR of heads, salivary glands and ovaries: P < 0.05; virus load in heads and salivary glands: P < 0.05; virus load in ovaries: P < 0.001). And then, fourteen days after the DENV-2-infectious blood meal, females of the susceptible and resistant strains were allow to bite 5-day-old suckling mice. Both stains of mosquito can transmit DENV-2 to mice, but the onset of viremia was later in the mice biting by resistant group as well as lower virus copies in serum and brains, suggesting that the horizontal transmission of the resistant strain is lower than the susceptible strain. Meanwhile, we also detected IR of egg pools of the two strains on 14 dpi and found that the resistant strain were less capable of vertical transmission than susceptible mosquitoes. In addition, the average survival time of the resistant females infected with DENV-2 was 16 days, which was the shortest among the four groups of female mosquitoes, suggesting that deltamethrin resistance would shorten the life span of female Aedes albopictus infected with DENV-2.Conclusions/SignificanceAs Aedes albopictus developing high resistance to deltamethrin, the resistance prolonged the growth and development of larvae, shorten the life span of adults, as well as reduced the vector competence of resistant Aedes albopictus for DENV-2. It can be concluded that the resistance to deltamethrin in Aedes albopictus is a double-edged sword, which not only endow the mosquito survive under the pressure of insecticide, but also increase the fitness cost and decrease its vector competence. However, Aedes albopictus resistant to deltamethrin can still complete the external incubation period and transmit dengue virus, which remains a potential vector for dengue virus transmission and becomes a threat to public health. Therefore, we should pay high attention for the problem of insecticide resistance so that to better prevent and control mosquito-borne diseases.     

The transmission of potato virus Y by aphids of different vectoring abilities

Adult apterae of Myzus persicae and Macrosiphum euphorbiae that did not transmit potato virus Y^N (PVY^N) in a first test were as likely to transmit the virus in a subsequent test as those that did transmit on the first occasion. Only 16% of M. persicae that were allowed a single acquisition probe into a leaf infected with both PVY^O and PVY^N transmitted both strains, 37% transmitted either PVY^O or PVY^N and 47% did not transmit. There was no difference in the duration of probes that did or did not result in virus transmission. Statistical models were fitted to data on the frequency of transmission of PVY^O, PVY^N or both PVY^O and PVY^N by M. persicae and by aphids of poorer vector species, M. euphorbiae and Rhopalosiphum padi. Transmission of the two viruses ocurred independently of each other and consequently transmission of both was rare with M. euphorbiae and R. padi. Mineral oil applied to leaves infected with both strains diminished the frequency of transmission by M. persicae. Fitted models suggested that the aphids that probed through the oil droplets on leaves treated 30 min previously did not transmit virus, and that 24 h later, when the droplets had spread, aphids probing through them could transmit but with a decreased ability.     

PHENOL OXIDASE ACTIVITY IN ANOPHELES SINENSIS AND AEDES ALBOPZCTUS EXPOSED TO MICROFILARIAE OF BRUGIA MALAYI

Abstract Phenol oxidase (PO activity was investigated in cell-free hemolymph collected from Anopheles sinensis and Aedes albopictlcs female adults intrathoracically inoculated with Brugia dayi microfilariae (mff), inoculated with saline alone, or from uninoculated mosquitoes. The activity of PO from uninoculated 1-day-old mosquitoes was significantly greater than those of mosquitoes on 3, 12 and 16 day. PO activity in mff-inoculated A. sinensis at 24 h postinoculation (PI) was 2–3 times higher as compared with uninoculated or saline-inoculated mosquitoes. Inoculation of B. malayi mff into A. albopictus elicited ?-fold increase in PO activity at 24 h PI as compared with uninoculated mosquitoes. Immune-activated levels of PO activity in A. alboplctus was significantly higher as compared with those seen in A. sinensis. The relationship of observed differences in PO activity to differences in immunological capability between A. sinensis and A. albopictus is discussed.     

Exposure to chikungunya virus and adult longevity in Aedes aegypti (L.) and Aedes albopictus (Skuse)

Chikungunya virus (CHIKV) recently emerged as a global threat to public health through its adaptation to the cosmopolitan mosquito Aedes albopictus Skuse. Aedes albopictus is highly susceptible to the emergent strain of CHIKV, relative to the historical vector of CHIKV, Aedes aegypti (L.). We hypothesized that the high susceptibility of Ae. albopictus to CHIKV may have a cost in terms of longevity and fecundity among infected vs non‐infected mosquitoes, relative to Ae. aegypti. We performed a longevity experiment comparing Ae. aegypti and Ae. albopictus exposed to the emergent strain of CHIKV (LR‐2006OPY1). We found a small but significant decrease in longevity of Ae. albopictus, but not Ae. aegypti, in response to exposure to CHIKV. We did not observe significant differences in numbers of eggs laid by either species in response to exposure. Longevity and body titer of infected Ae. albopictus were significantly negatively correlated, such that individuals that lived longer had lower viral body titers when they died. The cost of exposure, while not high, suggests there may be physiological constraints in the evolution of viral infectiousness in its insect vector.     

Chikungunya Virus and Aedes Mosquitoes: Saliva Is Infectious as soon as Two Days after Oral Infection

Background

Aedes aegypti and Aedes albopictus are potential vectors of chikungunya virus (CHIKV). The recent CHIKV outbreaks were caused by a new variant characterized by a mutation in the E1 glycoprotein gene (E1-226V) which has favored a better transmissibility by Ae. albopictus. As Ae. albopictus tends to replace Ae. aegypti in many regions, one question remained: is Ae. albopictus as efficient as Ae. aegypti to transmit the variant E1-226V of CHIKV?

Methodology and Findings

We infected orally both species with the variant E1-226V and estimated the infection, the viral dissemination, and the transmission rate by real time RT-PCR. Additionally, we used an in vitro assay to determine the amount of virus delivered by mosquitoes in their saliva. We found that Ae. aegypti as well as Ae. albopictus ensured a high replication of the virus which underwent an efficient dissemination as detectable in the salivary glands at day 2 post-infection (pi). Infectious CHIKV particles were delivered by salivary glands from day 2 with a maximum at day 6 pi for Ae. albopictus (10^3.3 PFU) and day 7 pi for Ae. aegypti (10^2.5 PFU).

Conclusions

Ae. albopictus is slightly more efficient than Ae. aegypti to transmit the variant E1-226V of CHIKV. These results will help to design an efficient vector control to limit transmission as soon as the first human cases are diagnosed.     

Characterization of two temperature-sensitive mutants of Sigma virus (authors transl)

Summary Temperature-sensitive mutants have been isolated from Drosophila Sigma virus, a Rhabdovirus inducing CO₂ sensitivity in Drosophila melanogaster. We have studied the decay of infectious centers at non permissive temperature. The proportion of destroyed infectious centers is the same for the wild type, ts⁺, and for ts9. On the opposite, it is more important for ts 4. Temperature-sensitive function of ts 4 appears necessary to the viral genome replication. With the three clones, ts⁺, ts 4 and ts 9, we have obtained stabilized Drosophila females able to transmit Sigma virus to their whole progeny. We have tried to see in each case, if stabilized flies could transmit the virus to their progeny at non permissive temperature. Flies stabilized with ts⁺ and ts 9 can, flies stabilized with ts 4 cannot. Therefore two categories of mutants are defined: those that are transmitted hereditarily. at non permissive temperature, and not blocked in genome replication. Those that are blocked in genome replication and not transmitted. When the virus cannot replicate, the divisions in the germ line cells dilute the viral genomes. The consequence will be a real healing of germ line cells, and then a break in hereditary transmission by stabilized flies. All the results with temperature-sensitive mutants are coherent with this hypothesis.

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Étude de mutants thermosensibles du virus Sigma

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Mémoire présenté par F. Gros     

Bacterial microbiota assemblage in Aedes albopictus mosquitoes and its impacts on larval development

Interactions between bacterial microbiota and mosquitoes play an important role in mosquitoes’ capacity to transmit pathogens. However, microbiota assemblages within mosquitoes and the impact of microbiota in environments on mosquito development and survival remain unclear. This study examined microbiota assemblages and the effects of aquatic environment microbiota on the larval development of the Aedes albopictus mosquito, an important dengue virus vector. Life table studies have found that reducing bacterial load in natural aquatic habitats through water filtering and treatment with antibiotics significantly reduced the larva‐to‐adult emergence rate. This finding was consistent in two types of larval habitats examined—discarded tires and flowerpots, suggesting that bacteria play a crucial role in larval development. Pyrosequencing of the bacterial 16S rRNA gene was used to determine the diversity of bacterial communities in larval habitats and the resulting numbers of mosquitoes under both laboratory and field conditions. The microbiota profiling identified common shared bacteria among samples from different years; further studies are needed to determine whether these bacteria represent a core microbiota. The highest microbiota diversity was found in aquatic habitats, followed by mosquito larvae, and the lowest in adult mosquitoes. Mosquito larvae ingested their bacterial microbiota and nutrients from aquatic habitats of high microbiota diversity. Taken together, the results support the observation that Ae. albopictus larvae are able to utilize diverse bacteria from aquatic habitats and that live bacteria from aquatic habitats play an important role in larval mosquito development and survival. These findings provide new insights into bacteria's role in mosquito larval ecology.     

Comparative transmission of bean leaf roll and pea enation mosaic viruses by aphids

Acyrthosiphon pisum was a more efficient vector than Myzus persicae of bean leaf roll virus (BLRV), but the two species transmitted pea enation mosaic virus (PEMV) equally well and much more often than Megoura viciae. M. viciae did not transmit BLRV, and Aphis fabae did not transmit BLRV or PEMV. BLRV and PEMV were transmitted more often by nymphs of A. pisum than by adult apterae or alatae that fed on infected plants only as adults, but both viruses were readily transmitted by adults that had developed on infected plants. The shortest time in which nymphs acquired BLRV was 2 h, and 50 % transmitted after an acquisition period of 4 days. Some nymphs acquired PEMV in 30 min and 50% in 8 h. The shortest time for inoculation of BLRV by adults was 15 min, but some transmitted PEMV in probes lasting less than 1 min. The median latent periods of BLRV and PEMV in aphids fed for 12 h on infected plants were, respectively, 105 and 44 h. Clones of A. pisum differed in their ability to transmit BLRV and PEMV, and efficiency in transmitting the two viruses seemed to be unrelated. Some aphids that fed successively on plants infected with each virus transmitted both viruses, and infectivity with one virus did not seem to affect transmission of the other.     

The mosquitoes of eastern Tennessee: studies on abundance,habitat preferences,and host‐seeking behaviors

A significant increase in the number of reported cases of La Crosse virus (LACV) infections in eastern Tennessee has occurred in the last ten years. The objective of this study was to determine the abundance and habitat preferences of the potential vectors of LACV in this region. Adult host‐seeking mosquitoes were collected using CO₂‐baited CDC light traps and a series of human‐landing catches in eastern Tennessee from 2004 to 2006. A total of 4,200 female mosquitoes of 23 species was collected by CO₂‐baited CDC trapping at ten sites during the study period. Aedes albopictus (Skuse) was the most abundant mosquito collected at all sites and vegetation types, with the ratios of total Ae. albopictus to Ae. triseriatus (Say) females collected being 2.1:1 in 2004, 3.8:1 in 2005, and 4.9:1 in 2006. Ten species were collected during a series of human‐landing catches made at four different sites; one probable and three confirmed case sites of LACV infections, totaling 528 female mosquitoes. Aedes albopictus was the most abundant species collected, with a 4:1 ratio of Ae. albopictus to Ae. triseriatus females. Aedes albopictus exhibited two clear peaks of “landing” activity, one in the early morning and one in the late afternoon or early evening. Simple and multiple regression analyses of the predictors of the number of mosquitoes collected showed that populations of Ae. albopictus were three times more likely to be collected overall than Ae. triseriatus. Species (Ae. albopictus), vegetation (residential), and the previous cumulative precipitation for the four weeks prior to collection were significantly (P < 0.05) associated with the number of mosquitoes collected by CO₂‐baited CDC trapping. Aedes albopictus was also more likely to be collected than Ae. triseriatus at confirmed cases of LACV infections.     

Modeling a single season of Aedes albopictus populations based on host‐seeking data in response to temperature and precipitation in eastern Tennessee

In the southern Appalachia of the U.S., Aedes mosquitoes maintain and transmit La Crosse virus (LACV) which causes La Crosse encephalitis, a neuroinvasive disease of children. In response to mosquito outbreaks, communities organize prevention, detection, and response measures that are dependent on local characteristics of the mosquito population and the community. Knowing Ae. albopictus is an accessory vector of LACV and a nuisance biter, our objective was to build a system of ordinary differential equations to model dynamics in a single season using our data and readily available environmental variables that can reflect the abundance and activity of Ae. albopictus. Consequently, we built an Ae. albopictus single‐season mathematical model for eastern Tennessee to fit our 2013 mosquito collection data in order to understand the population fluctuations. We included precipitation, temperature, and rate of change of temperature in the model because Aedes mosquitoes oviposit desiccant tolerant eggs with peak activity occurring over 26° C and those data are readily available and used frequently as forecast predictors. Our ordinary differential equation model accurately fits the data and facilitates predictions and better understanding of Ae. albopictus populations in southern Appalachia.     

Understanding the mechanism of Chikungunya virus vector competence in three species of mosquitoes

Chikungunya virus (CHIKV) is primarily transmitted by Aedes spp. mosquitoes. The present study investigated vector competence for CHIKV in Aedes aegypti and Aedes albopictus mosquitoes found in Madurai, South India. The role of receptor proteins on midguts contributing to permissiveness of CHIKV to Aedes spp. mosquitoes was also undertaken. Mosquitoes were orally infected with CHIKV DRDE‐06. Infection of midguts and dissemination to heads was confirmed by immunofluorescence assay at different time points. A plaque assay was performed from mosquito homogenates at different time points to study CHIKV replication. Presence of putative CHIKV receptor proteins on mosquito midgut epithelial cells was detected by virus overlay protein binding assay (VOPBA). The identity of these proteins was established using mass spectrometry. CHIKV infection of Ae. aegypti and Ae. albopictus midguts and dissemination to heads was observed to be similar. A plaque assay performed with infected mosquito homogenates revealed that CHIKV replication dynamics was similar in Aedes sp. mosquitoes until 28 days post infection. VOPBA performed with mosquito midgut membrane proteins revealed that prohibitin could serve as a putative CHIKV receptor on Aedes mosquito midguts, whereas an absence of CHIKV binding protein/s on Culex quinquefasciatus midguts can partially explain the non‐permissiveness of these mosquitoes to infection.     

Vertical transmission of hepatitis B virus in Culex quinquefasciatus

An investigation of the vertical transmission of hepatitis B virus (HBV) in Culex quinquefasciatus Say revealed the presence of low levels of the virus in adult F1 progeny from the first ovarian cycle of mosquitoes infected by feeding on HBV positive human blood. HBV was not transmitted vertically during the second, third and fourth ovarian cycles nor to the F2 generation. The salivary glands, ovaries and faeces of the F1 generation did not contain detectable levels of HBV. Progeny of female Cx quinquefasciatus mated with F1 males were negative for HBV.     

Who is eating fructose within the Aedes albopictus gut microbiota?

The Asian tiger mosquito Aedes albopictus is a major public health concern because of its invasive success and its ability to transmit pathogens. Given the low availability of treatments against mosquito-borne diseases, vector control remains the most suitable strategy. The methods used thus far are becoming less effective, but recent strategies have emerged from the study of mosquito-associated microorganisms. Although the role of the microbiota in insect biology does not require further proof, much remains to be deciphered in mosquitoes, especially the contribution of the microbiota to host nutrient metabolism. Mosquitoes feed on plant nectar, composed of mostly fructose. We used stable isotope probing to identify bacteria and fungi assimilating fructose within the gut of Ae. albopictus. Mosquitoes were fed a ¹³C-labelled fructose solution for 24 h. Differences in the active microbial community according to the sex of mosquitoes were highlighted. The bacterium Lelliottia and the fungi Cladosporium and Aspergillus dominated the active microbiota in males, whereas the bacterium Ampullimonas and the yeast Cyberlindnera were the most active in females. This study is the first to investigate trophic interactions between Ae. albopictus and its microbiota, thus underscoring the importance of the microbial component in nectar feeding in mosquitoes.     

Host range, purification and properties of potato virus T

Potato virus T (PVT) infected nine species of tuber-bearing Solanum, most of them symptomlessly, and as a rule was transmitted through the tubers to progeny plants: two genotypes of S. tuberosum ssp. andigena were not infected. The virus was also transmitted by inoculation with sap to 37 other species in eight plant families. Chenopodium amaranticolor is useful as an indicator host, C quinoa as a source of virus for purification, and Phaseolus vulgaris as a local-lesion assay host; the systemic symptoms in Datura stramonium, Nicotiana debneyi and in these three species are useful for diagnosis. Attempts to transmit PVT by aphids failed, but the virus was transmitted through seed to progeny seedlings of four solanaceous species, and from pollen to seed of S. demissum. PVT was purified by clarifying sap with n-butanol or bentonite, followed by precipitation with polyethylene glycol, differential centrifugation and sedimentation in a sucrose density gradient. Purified preparations had an E260/E280 ratio of 1.18 and contained a single infective component with a sedimentation coefficient of 99 S. This component consisted of flexuous filamentous particles of about 640 times 12 nm that showed a characteristic substructure when stained with uranyl acetate. The virus particles contained a single species of infective single-stranded RNA, of molecular weight 2–2 times 106 daltons, and a single species of polypeptide of molecular weight about 27 000 daltons. PVT is serologically related to apple stem grooving virus but not to four other common potato viruses with flexuous filamentous particles. Apple stem grooving virus and PVT cause similar symptoms in several hosts, but also differ somewhat in host range and symptomatology. Apple stem grooving virus did not infect potato, caused additional symptoms in C. quinoa also infected with PVT, and its particles did not show the structural features specific to PVT. The two viruses are considered to be distinct. The cryptogram of PVT is R/1:2–2/(5): E/E: S/C.     

Genetic and nongenetic factors in expression of infectious murine leukemia viruses in mice of the DBA/2 x RF cross

Mice of the RF and DBA/2 strains possess endogenous ecotropic murine leukemia virus (E-MuLV) genomes but express only low to undetectable levels of infectious virus in their lymphoid tissues. F1 mice of this cross showed high levels of infectious E-MuLV if DBA/2 was the maternal parent but very low levels if RF was the maternal parent. E-MuLV expression, if present, was always higher in the spleen than in the thymus. Studies of reciprocal backcross generations with both parental strains indicated that the presence of the virus was governed by a single dominant autosomal locus present in the RF strain, and that RF females, but neither RF males nor DBA/2 females or males, transmitted a non-Mendelian factor which powerfully suppressed virus expression in their progeny. Some but not all (DBA/2♀ × RF♂)F1 females also possessed the capacity to transmit this maternal suppression to their progeny. Xenotropic murine leukemia virus (X-MuLV) showed a different pattern of expression in this cross. In the thymus it was detected in a minority of DBA/2 and in no RF mice; in crosses the presence of X-MuLV in this organ was independent of the presence of E-MuLV. In the spleen, X-MuLV was detected only in a percentage of E-MuLV-positive mice. The maternal factor from RF mothers which suppressed E-MuLV did not suppress thymic expression of X-MuLV. Skin painting with 3-methylcholanthrene induced a high incidence of thymic lymphoma in mice of both parental strains and in F1 hybrids, all of which normally show only low incidences of the diseases; the treatment did not induce markedly increased expression of E-MuLV or X-MuLV in mice of either parental strain, although it did abrogate the diminution of E-MuLV titers seen with age in (DBA/2♀ × RF♂)F1 mice beyond the age of three months.     

Maternally transmitted resistance to lymphoma development in mice of reciprocal crosses of the RF/J and AKR/J strains

Females but not males of the low-lymphoma RF/J strain transmit a non-Mendelian factor which suppresses the development of lymphoma in F1 crosses with mice of the high-lymphoma AKR/J strain. Suppression of lymphoma was also evident in the first backcross generation to the parental AKR strain, but only when (RF female x AKR male)F1 mice had been the female parent. This "maternal resistance factor" was transmitted independently of the dominant, lymphoma-suppressing Fv-1n allele transmitted by both males and females of the RF strain, but the suppressive capacities of the two factors appeared to be additive. In this cross, F1 progeny of RF females also showed marked suppression of ecotropic murine leukemia virus expression by comparison with mice of the reciprocal F1 cross, but this suppression of virus expression was not detected in the lymphoma-suppressed AKR backcross population. The observation of lymphoma suppression in the absence of ectropic virus suppression in mice of the (RF X AKR)F1 female x AKR male backross generation indicates a qualitative or quantitative difference in the determination of these two effects.     

Wolbachia pipientis occurs in Aedes aegypti populations in New Mexico and Florida,USA

The mosquitoes Aedes aegypti (L.) and Ae. albopictus Skuse are the major vectors of dengue, Zika, yellow fever, and chikungunya viruses worldwide. Wolbachia, an endosymbiotic bacterium present in many insects, is being utilized in novel vector control strategies to manipulate mosquito life history and vector competence to curb virus transmission. Earlier studies have found that Wolbachia is commonly detected in Ae. albopictus but rarely detected in Ae. aegypti. In this study, we used a two‐step PCR assay to detect Wolbachia in wild‐collected samples of Ae. aegypti. The PCR products were sequenced to validate amplicons and identify Wolbachia strains. A loop‐mediated isothermal amplification (LAMP) assay was developed and used for detecting Wolbachia in selected mosquito specimens as well. We found Wolbachia in 85/148 (57.4%) wild Ae. aegypti specimens from various cities in New Mexico, and in 2/46 (4.3%) from St. Augustine, Florida. Wolbachia was not detected in 94 samples of Ae. aegypti from Deer Park, Harris County, Texas. Wolbachia detected in Ae. aegypti from both New Mexico and Florida was the wAlbB strain of Wolbachia pipientis. A Wolbachia‐positive colony of Ae. aegypti was established from pupae collected in Las Cruces, New Mexico, in 2018. The infected females of this strain transmitted Wolbachia to their progeny when crossed with males of Rockefeller strain of Ae. aegypti, which does not carry Wolbachia. In contrast, none of the progeny of Las Cruces males mated to Rockefeller females were infected with Wolbachia.