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J S Mackenzie - One of the best experts on this subject based on the ideXlab platform.
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discovery of jogalong virus a novel hepacivirus identified in a Culex annulirostris skuse mosquito from the kimberley region of western australia
PLOS ONE, 2020Co-Authors: Avram Levy, Rachel A Yates, Nilusha Somaweera, Peter J Neville, Jay Nicholson, M D Lindsay, J S Mackenzie, Simon H. Williams, Komal JainAbstract:The discovery of hepaciviruses in non-human hosts has accelerated following the advancement of high-throughput sequencing technology. Hepaciviruses have now been described in reptiles, fish, birds, and an extensive array of mammals. Using metagenomic sequencing on pooled samples of field-collected Culex annulirostris mosquitoes, we discovered a divergent hepacivirus-like sequence, named Jogalong virus, from the Kimberley region in northern Western Australia. Using PCR, we screened the same 300 individual mosquitoes and found just a single positive sample (1/300, 0.33%). Phylogenetic analysis of the hepacivirus NS5B protein places Jogalong virus within the genus Hepacivirus but on a distinct and deeply rooted monophyletic branch shared with duck hepacivirus, suggesting a notably different evolutionary history. Vertebrate barcoding PCR targeting two mitochondrial genes, cytochrome c oxidase subunit I and cytochrome b, indicated that the Jogalong virus-positive mosquito had recently fed on the tawny frogmouth (Podargus strigoides), although it is currently unknown whether this bird species contributes to the natural ecology of this virus.
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transmission of japanese encephalitis virus from the black flying fox pteropus alecto to Culex annulirostris mosquitoes despite the absence of detectable viremia
American Journal of Tropical Medicine and Hygiene, 2009Co-Authors: Andrew F Van Den Hurk, Craig S Smith, Judith A Northill, Carmel T Taylor, Cassie C Jansen, Hume Field, Ina Smith, Greg A. Smith, J S MackenzieAbstract:To determine the potential role of flying foxes in transmission cycles of Japanese encephalitis virus (JEV) in Australia, we exposed Pteropus alecto (Megachiroptera: Pteropididae) to JEV via infected Culex annulirostris mosquitoes or inoculation. No flying foxes developed symptoms consistent with JEV infection. Anti-JEV IgG antibodies developed in 6/10 flying foxes exposed to infected Cx. annulirostris and in 5/5 inoculated flying foxes. Low-level viremia was detected by real-time reverse transcriptase polymerase chain reaction in 1/5 inoculated flying foxes and this animal was able to infect recipient mosquitoes. Although viremia was not detected in any of the 10 flying foxes that were exposed to JEV by mosquito bite, two animals infected recipient mosquitoes. Likewise, an inoculated flying fox without detectable viremia infected recipient mosquitoes. Although infection rates in recipient mosquitoes were low, the high population densities in roosting camps, coupled with migratory behavior indicate that flying foxes could play a role in the dispersal of JEV.
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epizootic activity of murray valley encephalitis and kunjin viruses in an aboriginal community in the southeast kimberley region of western australia results of mosquito fauna and virus isolation studies
American Journal of Tropical Medicine and Hygiene, 2003Co-Authors: A K Broom, Michael D A Lindsay, A E Wright, David W Smith, J S MackenzieAbstract:We undertook annual surveys of flavivirus virus activity in the community of Billiluna of Western Australia in the southeast Kimberley region between 1989 and 2001. Culex annulirostris was the dominant mosquito species, particularly in years of above average rains and flooding. Murray Valley encephalitis (MVE) virus was isolated in 8 of the 13 years of the study from seven mosquito species, but more than 90% of the isolates were from Cx. annulirostris. The results suggest that MVE virus is epizootic in the region, with activity only apparent in years with average or above average rainfall and increased numbers of Cx. annulirostris. High levels of MVE virus activity and associated human cases were detected only once (in 1993) during the survey period. Activity of MVE virus could only be partially correlated with wet season rainfall and flooding, suggesting that a number of other factors must also be considered to accurately predict MVE virus activity at such communities.
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field evaluation of a sentinel mosquito diptera culicidae trap system to detect japanese encephalitis in remote australia
Journal of Medical Entomology, 2003Co-Authors: Scott A. Ritchie, Cheryl A Johansen, Judith A Northill, Greg A. Smith, Andrew F. Van Den Hurk, Brian L. Montgomery, Alyssa T. Pyke, Roy A Hall, J S MackenzieAbstract:Incursions of Japanese encephalitis (JE) virus into northern Queensland are currently monitored using sentinel pigs. However, the maintenance of these pigs is expensive, and because pigs are the major amplifying hosts of the virus, they may contribute to JE transmission. Therefore, we evaluated a mosquito-based detection system to potentially replace the sentinel pigs. Single, inactivated JE-infected Culex annulirostris Skuse and C. sitiens Wiedemann were placed into pools of uninfected mosquitoes that were housed in a MosquitoMagnet Pro (MM) trap set under wet season field conditions in Cairns, Queensland for 0, 7, or 14 d. JE viral RNA was detected (cycling threshold [CT] = 40) in 11/12, 10/14, and 2/5 pools containing 200, 1,000, and 5,000 mosquitoes, respectively, using a TaqMan real-time reverse transcription-polymerase chain reaction (RT-PCR). The ability to detect virus was not affected by the length of time pools were maintained under field conditions, although the CT score tended to increase with field exposure time. Furthermore, JE viral RNA was detected in three pools of 1,000 mosquitoes collected from Badu Island using a MM trap. These results indicated that a mosquito trap system employing self-powered traps, such as the MosquitoMagnet, and a real-time PCR system, could be used to monitor for JE in remote areas.
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japanese encephalitis in north queensland australia 1998
The Medical Journal of Australia, 1999Co-Authors: Jeffrey N Hanna, Cheryl A Johansen, Scott A. Ritchie, Alyssa T. Pyke, D A Phillips, J M Lee, Susan L Hills, A F Van Den Hurk, J S MackenzieAbstract:Objective: To describe the circumstances of two cases of Japanese encephalitis (JE) in north Queensland in 1998, including one acquired on the Australian mainland. Design: Serological surveillance of sentinel pigs for JE virus activity; serological surveys of humans and pigs and viral cultures of mosquito collections. Setting: Islands in the Torres Strait and communities in the Northern Peninsula Area (NPA) and near the mouth of the Mitchell River in Cape York, Queensland, in the 1998 wet season (December 1997-May 1998). Results: Sentinel pigs in the Torres Strait began to seroconvert to JE virus in February 1998, just before onset of JE in an unvaccinated 12-year-old boy on Badu island. By mid-April, most sentinel pigs had seroconverted. Numerous JE viruses were isolated from Culex annulirostris mosquitoes collected on Badu. In early March, a person working at the mouth of the Mitchell River developed JE. Serological surveys showed recent JE virus infection in 13 young pigs on a nearby farm, but not in 488 nearby residents. In NPA communities, sentinel pigs seroconverted slowly and JE viruses were isolated from three, but none of 604 residents showed evidence of recent infection. Nucleotide sequencing showed that 1998 JE virus isolates from the Torres Strait were virtually identical not only to the 1998 isolate from an NPA pig, but also to previous (1995) Badu isolates. Conclusions: JE virus activity was more widespread in north Queensland in the 1998 wet season than in the three previous wet seasons, but ecological circumstances leg, less intensive pig husbandry, fewer mosquitoes) appear to have limited transmission on the mainland. Nucleotide sequencing indicated a common source for the 1995 and 1998 JE viruses. Circumstantial evidence suggests that cyclonic winds carried infected mosquitoes from Papua New Guinea.
Andrew F. Van Den Hurk - One of the best experts on this subject based on the ideXlab platform.
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morphological versus molecular identification of Culex annulirostris skuse and Culex palpalis taylor key members of the Culex sitiens diptera culicidae subgroup in australasia
Australian Journal of Entomology, 2013Co-Authors: Cassie C Jansen, Andrew F. Van Den Hurk, Stephane Hemmerter, Peter I Whelan, Nigel W BeebeAbstract:Members of the Culex sitiens subgroup of mosquitoes are important arbovirus vectors in the Australasian region. However, some species in this group, particularly Cx.annulirostris and Cx.palpalis, are difficult to distinguish based on morphological characters alone. We evaluated the reliability of morphological characters commonly used in taxonomic keys against a PCR-based diagnostic tool that examined the ribosomal ITS1 gene region. Although reliable morphological characters allow identification, molecular identification remains the most accurate means for distinguishing Cx. annulirostris and Cx. palpalis.
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Culex annulirostris diptera culicidae host feeding patterns and japanese encephalitis virus ecology in northern australia
Journal of Medical Entomology, 2012Co-Authors: Sonja Hallmendelin, Cassie C Jansen, Scott A. Ritchie, Andrew F. Van Den Hurk, Brian L. Montgomery, Roy A Hall, Wai Yuen CheahAbstract:Japanese encephalitis virus (JEV) transmission in northern Australia has, in the past, been facilitated by Culex annulirostris Skuse feeding on domestic pigs, the primary amplifying hosts of the virus. To further characterize mosquito feeding behavior in northern Australia, 1,128 bloodmeals from Cx. annulirostris were analyzed using a double-antibody enzyme-linked immunosorbent assay. Overall, Cx. annulirostris obtained >94% of blood meals from mammals, comprising marsupials (37%), pigs (20%), dogs (16%), and cows (11%), although the proportion feeding on each of these host types varied between study locations. Where JEV activity was detected, feeding rates on pigs were relatively high. At the location that yielded the first Australian mainland isolate of JEV from mosquitoes, feral pigs (in the absence of domestic pigs) accounted for 82% of bloodmeals identified, representing the first occasion that feeding on feral pigs has been associated with JEV transmission in Australia. Interestingly, <3% of Cx. annulirostris had fed on pigs at locations on Badu Island where JEV was detected in multiple pools of mosquitoes in a concurrent study. This suggests that either alternative hosts, such as birds, which comprised 21% of blood meals identified, or infected mosquitoes immigrating from areas where domestic pigs are housed, may have contributed to transmission at this location. Because Cx. annulirostris is both an opportunistic feeder and the primary JEV vector in the region, environmental characteristics and host presence can determine JEV transmission dynamics in northern Australia.
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field evaluation of a sentinel mosquito diptera culicidae trap system to detect japanese encephalitis in remote australia
Journal of Medical Entomology, 2003Co-Authors: Scott A. Ritchie, Cheryl A Johansen, Judith A Northill, Greg A. Smith, Andrew F. Van Den Hurk, Brian L. Montgomery, Alyssa T. Pyke, Roy A Hall, J S MackenzieAbstract:Incursions of Japanese encephalitis (JE) virus into northern Queensland are currently monitored using sentinel pigs. However, the maintenance of these pigs is expensive, and because pigs are the major amplifying hosts of the virus, they may contribute to JE transmission. Therefore, we evaluated a mosquito-based detection system to potentially replace the sentinel pigs. Single, inactivated JE-infected Culex annulirostris Skuse and C. sitiens Wiedemann were placed into pools of uninfected mosquitoes that were housed in a MosquitoMagnet Pro (MM) trap set under wet season field conditions in Cairns, Queensland for 0, 7, or 14 d. JE viral RNA was detected (cycling threshold [CT] = 40) in 11/12, 10/14, and 2/5 pools containing 200, 1,000, and 5,000 mosquitoes, respectively, using a TaqMan real-time reverse transcription-polymerase chain reaction (RT-PCR). The ability to detect virus was not affected by the length of time pools were maintained under field conditions, although the CT score tended to increase with field exposure time. Furthermore, JE viral RNA was detected in three pools of 1,000 mosquitoes collected from Badu Island using a MM trap. These results indicated that a mosquito trap system employing self-powered traps, such as the MosquitoMagnet, and a real-time PCR system, could be used to monitor for JE in remote areas.
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isolation of japanese encephalitis virus from Culex annulirostris in australia
American Journal of Tropical Medicine and Hygiene, 1997Co-Authors: Scott A. Ritchie, J S Mackenzie, Debbie Phillips, A K Broom, Michael Poidinger, Andrew F. Van Den HurkAbstract:Mosquitoes were collected using CO and octenol-baited light traps during an outbreak of Japanese encephalitis (JE) on Badu Island in the Torres Strait, Australia in April 1995. A total of 13, 300 mosquitoes comprising 12 species were processed for virus isolation. Eight isolates of JE virus were obtained from Culex annulirostris, with a carriage rate of 2.97: 1, 000; this mosquito also yielded one Sindbis virus isolate. A reverse transcriptase-polymerase chain reaction was used to sequence the JE viruses, which were compared with published sequences. The eight isolates were 90% homologous with known JE strains but only 68% homologous with other flaviviruses. Among the isolates, 99% homology was obtained, suggesting a common point of origin.
Scott A. Ritchie - One of the best experts on this subject based on the ideXlab platform.
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Culex annulirostris diptera culicidae host feeding patterns and japanese encephalitis virus ecology in northern australia
Journal of Medical Entomology, 2012Co-Authors: Sonja Hallmendelin, Cassie C Jansen, Scott A. Ritchie, Andrew F. Van Den Hurk, Brian L. Montgomery, Roy A Hall, Wai Yuen CheahAbstract:Japanese encephalitis virus (JEV) transmission in northern Australia has, in the past, been facilitated by Culex annulirostris Skuse feeding on domestic pigs, the primary amplifying hosts of the virus. To further characterize mosquito feeding behavior in northern Australia, 1,128 bloodmeals from Cx. annulirostris were analyzed using a double-antibody enzyme-linked immunosorbent assay. Overall, Cx. annulirostris obtained >94% of blood meals from mammals, comprising marsupials (37%), pigs (20%), dogs (16%), and cows (11%), although the proportion feeding on each of these host types varied between study locations. Where JEV activity was detected, feeding rates on pigs were relatively high. At the location that yielded the first Australian mainland isolate of JEV from mosquitoes, feral pigs (in the absence of domestic pigs) accounted for 82% of bloodmeals identified, representing the first occasion that feeding on feral pigs has been associated with JEV transmission in Australia. Interestingly, <3% of Cx. annulirostris had fed on pigs at locations on Badu Island where JEV was detected in multiple pools of mosquitoes in a concurrent study. This suggests that either alternative hosts, such as birds, which comprised 21% of blood meals identified, or infected mosquitoes immigrating from areas where domestic pigs are housed, may have contributed to transmission at this location. Because Cx. annulirostris is both an opportunistic feeder and the primary JEV vector in the region, environmental characteristics and host presence can determine JEV transmission dynamics in northern Australia.
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field evaluation of a sentinel mosquito diptera culicidae trap system to detect japanese encephalitis in remote australia
Journal of Medical Entomology, 2003Co-Authors: Scott A. Ritchie, Cheryl A Johansen, Judith A Northill, Greg A. Smith, Andrew F. Van Den Hurk, Brian L. Montgomery, Alyssa T. Pyke, Roy A Hall, J S MackenzieAbstract:Incursions of Japanese encephalitis (JE) virus into northern Queensland are currently monitored using sentinel pigs. However, the maintenance of these pigs is expensive, and because pigs are the major amplifying hosts of the virus, they may contribute to JE transmission. Therefore, we evaluated a mosquito-based detection system to potentially replace the sentinel pigs. Single, inactivated JE-infected Culex annulirostris Skuse and C. sitiens Wiedemann were placed into pools of uninfected mosquitoes that were housed in a MosquitoMagnet Pro (MM) trap set under wet season field conditions in Cairns, Queensland for 0, 7, or 14 d. JE viral RNA was detected (cycling threshold [CT] = 40) in 11/12, 10/14, and 2/5 pools containing 200, 1,000, and 5,000 mosquitoes, respectively, using a TaqMan real-time reverse transcription-polymerase chain reaction (RT-PCR). The ability to detect virus was not affected by the length of time pools were maintained under field conditions, although the CT score tended to increase with field exposure time. Furthermore, JE viral RNA was detected in three pools of 1,000 mosquitoes collected from Badu Island using a MM trap. These results indicated that a mosquito trap system employing self-powered traps, such as the MosquitoMagnet, and a real-time PCR system, could be used to monitor for JE in remote areas.
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population structure and dispersal of the freshwater mosquitoes Culex annulirostris and Culex palpalis diptera culicidae in papua new guinea and northern australia
Journal of Medical Entomology, 2003Co-Authors: Scott A. Ritchie, Heather Faye Chapman, Jane Hughes, Brian H. KayAbstract:In 1995 and 1998, outbreaks of Japanese encephalitis (JE) virus occurred for the first time in Australia. Virus isolation from pools of mosquitoes indicated Culex annulirostris Skuse was the most likely vector. It was hypothesized that wind-blown mosquitoes introduced JE from Papua New Guinea to the Torres Strait and Cape York, northern Australia. This study used levels of genetic differentiation, as indirect evidence of dispersal of mosquitoes between the two continents. The results have demonstrated that in the region incorporating Western Province in PNG, the Torres Strait and Cape York Peninsula, Cx. annulirostris is represented by a panmictic population, indicating frequent widespread dispersal throughout the region of investigation. The closely related Cx. Palpalis Taylor was also present at some locations but the population structure of this species is uncertain. This supports the hypothesis that wind-blown Cx. annulirostris and possibly Cx. Palpalis could be a possible mechanism for introduction of JE virus into Australia.
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japanese encephalitis in north queensland australia 1998
The Medical Journal of Australia, 1999Co-Authors: Jeffrey N Hanna, Cheryl A Johansen, Scott A. Ritchie, Alyssa T. Pyke, D A Phillips, J M Lee, Susan L Hills, A F Van Den Hurk, J S MackenzieAbstract:Objective: To describe the circumstances of two cases of Japanese encephalitis (JE) in north Queensland in 1998, including one acquired on the Australian mainland. Design: Serological surveillance of sentinel pigs for JE virus activity; serological surveys of humans and pigs and viral cultures of mosquito collections. Setting: Islands in the Torres Strait and communities in the Northern Peninsula Area (NPA) and near the mouth of the Mitchell River in Cape York, Queensland, in the 1998 wet season (December 1997-May 1998). Results: Sentinel pigs in the Torres Strait began to seroconvert to JE virus in February 1998, just before onset of JE in an unvaccinated 12-year-old boy on Badu island. By mid-April, most sentinel pigs had seroconverted. Numerous JE viruses were isolated from Culex annulirostris mosquitoes collected on Badu. In early March, a person working at the mouth of the Mitchell River developed JE. Serological surveys showed recent JE virus infection in 13 young pigs on a nearby farm, but not in 488 nearby residents. In NPA communities, sentinel pigs seroconverted slowly and JE viruses were isolated from three, but none of 604 residents showed evidence of recent infection. Nucleotide sequencing showed that 1998 JE virus isolates from the Torres Strait were virtually identical not only to the 1998 isolate from an NPA pig, but also to previous (1995) Badu isolates. Conclusions: JE virus activity was more widespread in north Queensland in the 1998 wet season than in the three previous wet seasons, but ecological circumstances leg, less intensive pig husbandry, fewer mosquitoes) appear to have limited transmission on the mainland. Nucleotide sequencing indicated a common source for the 1995 and 1998 JE viruses. Circumstantial evidence suggests that cyclonic winds carried infected mosquitoes from Papua New Guinea.
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isolation of japanese encephalitis virus from Culex annulirostris in australia
American Journal of Tropical Medicine and Hygiene, 1997Co-Authors: Scott A. Ritchie, J S Mackenzie, Debbie Phillips, A K Broom, Michael Poidinger, Andrew F. Van Den HurkAbstract:Mosquitoes were collected using CO and octenol-baited light traps during an outbreak of Japanese encephalitis (JE) on Badu Island in the Torres Strait, Australia in April 1995. A total of 13, 300 mosquitoes comprising 12 species were processed for virus isolation. Eight isolates of JE virus were obtained from Culex annulirostris, with a carriage rate of 2.97: 1, 000; this mosquito also yielded one Sindbis virus isolate. A reverse transcriptase-polymerase chain reaction was used to sequence the JE viruses, which were compared with published sequences. The eight isolates were 90% homologous with known JE strains but only 68% homologous with other flaviviruses. Among the isolates, 99% homology was obtained, suggesting a common point of origin.
Brian H. Kay - One of the best experts on this subject based on the ideXlab platform.
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melanotaenia duboulayi influence oviposition site selection by Culex annulirostris diptera culicidae and aedes notoscriptus diptera culicidae but not Culex quinquefasciatus diptera culicidae
Environmental Entomology, 2010Co-Authors: Timothy P Hurst, Brian H. Kay, Michael D. Brown, Peter A RyanAbstract:Some species of mosquito can detect the presence of larvivorous fish and select against ovipositing in pools supporting them. The effect of kairomones released by the crimson-spotted rainbowfish Melanotaenia duboulayi (Castelnau) on the oviposition behavior of the freshwater mosquitoes Culex annulirostris Skuse, Culex quinquefasciatus Say, and Aedes notoscriptus Skuse was evaluated in both laboratory and outdoor artificial pool experiments. In the laboratory, colony-reared Cx. annulirostris selected against ovipositing in water that had contained M. duboulayi at densities of one fish per 5, 30, 180, and 1,080 liters. In contrast, gravid Ae. notoscriptus showed a preference for water that had contained the highest density of M. duboulayi (1 in 5 liters). Gravid Cx. quinquefasciatus were neither repelled nor attracted to water that had previously contained M. duboulayi. In outdoor artificial pool experiments, wild Cx. annulirostris females selected against ovipositing in pools containing caged M. duboulayi stocked at rates of 1, 4, and 10 g per 1,000 liters. When fish were removed from the pools, the repellent effect persisted for at least 24 h, whereas at the lower stocking rate, an avoidance response was not noted until 48 h after fish were placed in pools. This suggests a volatile substance, however, the exact nature of the kairomone/s has not been identified.
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laboratory evaluation of the effect of alternative prey and vegetation on predation of Culex annulirostris immatures by australian native fish species
Journal of The American Mosquito Control Association, 2006Co-Authors: Timothy P Hurst, Brian H. Kay, Michael D. Brown, Peter A RyanAbstract:The impact of alternative prey and simulated vegetation on Culex annulirostris Skuse predation efficacy by Australian smelt, Retropinna semoni (Retropinnidae); crimson-spotted rainbowfish, Melanotaenia duboulayi (Melanotaeniidae); empire gudgeon, Hypseleotris compressa (Eleotridae); estuary perchlet, Ambassis marianus (Ambassidae); firetail gudgeon, Hypseleotris galii (Eleotridae); fly-specked hardyhead, Craterocephalus stercusmuscarum (Atherinidae); and Pacific blue-eye, Pseudomugil signifer (Atherinidae), was evaluated in Queensland, Australia. The presence of chironomid midge larvae and tusked frog, Adelotus brevis (Leptodactylidae), tadpoles did not have a significant negative impact on the predation rates of Cx. annulirostris by these 7 fish species. Hypseleotris galii, M. duboulayi, and R. semoni demonstrated strong preference for larvae of Cx. annulirostris over both alternative prey species. In the presence of alternative prey species, the mean predation rate of M. duboulayi on larvae of Cx. annulirostris remained greater than that of other fish species tested. When evaluated at varying densities of simulated vegetation, predation rates of all fish species were similar to those reported in open conditions.
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evaluation of melanotaenia duboulayi atheriniformes melanotaeniidae hypseleotris galii perciformes eleotridae and larvicide vectolex wg bacillus sphaericus for integrated control of Culex annulirostris
Journal of The American Mosquito Control Association, 2006Co-Authors: Timothy P Hurst, Brian H. Kay, Michael D. Brown, Peter A RyanAbstract:Australian freshwater fish species Melanotaenia duboulayi and Hypseleotris galii were selected for a small plot field evaluation of an integrated pest management strategy using native fish and VectoLex® WG (Bacillus sphaericus) for the control of Culex annulirostris Skuse, the principal freshwater vector of arbovirus Ross River virus in Australia. When tested alone, the level of control afforded by M. duboulayi and H. galii was highly dependent on the prerelease density of mosquito larvae; and even when stocking rates as high as 10 g per pond (>30 kg/ha) were used, larval abundance was too high to attain adequate control from fish alone. In contrast, treatment with VectoLex WG at 500 g/ha resulted in 100% mortality of Cx. annulirostris immatures, but no residual activity was evident. The delayed reduction of Cx. annulirostris immatures in ponds stocked with fish alone, and the recolonization by Cx. annulirostris in ponds after treatment with B. sphaericus, did not occur when both treatments were combined.
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spatial statistical analysis of adult mosquito diptera culicidae counts an example using light trap data in redland shire southeastern queensland australia
Journal of Medical Entomology, 2004Co-Authors: Peter A Ryan, Scott A Lyons, D Alsemgeest, Paula Thomas, Brian H. KayAbstract:Many mosquito control agencies use carbon dioxide-baited traps as surveillance tools for adult vector populations. However, decisions regarding the number and location of trap sites and the frequency of collections are often based on logistical issues, and not on the bionomics or spatial distribution of the target species. Therefore, with the aim of providing practical information for adult mosquito surveillance programs, we used an array of 81 carbon dioxide- and octenol-baited lights traps to obtain weekly samples of adult mosquitoes in Redland Shire in southeastern Queensland, Australia. The spatial patterns of four different mosquito species were examined, and positive spatial autocorrelation in trap counts was evident for Ochlerotatus vigilax (Skuse), Coquillettidia linealis (Skuse), and Culex annulirostris Skuse, but not for the container species Ochlerotatus notoscriptus (Skuse). Of the three species that exhibited spatially correlated trap counts, the autocorrelation was greatest in Oc. vigilax at a lag distance of 0-1.5 km, with Moran's I values of 0.30-0.64. Moran's I indices were also positive and statistically significant (P < 0.05) at lag distances of 1.5-3.0 and 3.0-4.5 km on each of the 15 sampling occasions. However, at 3.0-4.5 km the Moran's I values were low, which indicated only weak spatial autocorrelation in trap counts. Universal kriging was used to estimate the numbers of each species at unsampled locations throughout the study area, and leave-one-out cross validation analyses indicated that this was a robust method for Cq. linealis and Oc. vigilax. In contrast, trap counts for the container-breeding species Oc. notoscriptus were randomly distributed and the interpolated counts were not reliable. Comparisons of weekly contour maps of adult mosquito counts indicated a consistent spatial pattern for Oc. vigilax and Cq. linealis. Particular geographic areas had consistently high or low numbers of vectors, and these patterns were stable from year to year. Definition of geographic areas with consistently high or low numbers of vectors may allow control activities to be focused in areas with the greatest risk of arbovirus transmission.
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population structure and dispersal of the freshwater mosquitoes Culex annulirostris and Culex palpalis diptera culicidae in papua new guinea and northern australia
Journal of Medical Entomology, 2003Co-Authors: Scott A. Ritchie, Heather Faye Chapman, Jane Hughes, Brian H. KayAbstract:In 1995 and 1998, outbreaks of Japanese encephalitis (JE) virus occurred for the first time in Australia. Virus isolation from pools of mosquitoes indicated Culex annulirostris Skuse was the most likely vector. It was hypothesized that wind-blown mosquitoes introduced JE from Papua New Guinea to the Torres Strait and Cape York, northern Australia. This study used levels of genetic differentiation, as indirect evidence of dispersal of mosquitoes between the two continents. The results have demonstrated that in the region incorporating Western Province in PNG, the Torres Strait and Cape York Peninsula, Cx. annulirostris is represented by a panmictic population, indicating frequent widespread dispersal throughout the region of investigation. The closely related Cx. Palpalis Taylor was also present at some locations but the population structure of this species is uncertain. This supports the hypothesis that wind-blown Cx. annulirostris and possibly Cx. Palpalis could be a possible mechanism for introduction of JE virus into Australia.
Thomas P Monath - One of the best experts on this subject based on the ideXlab platform.
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experimental infection of Culex annulirostris Culex gelidus and aedes vigilax with a yellow fever japanese encephalitis virus vaccine chimera chimerivax je
American Journal of Tropical Medicine and Hygiene, 2006Co-Authors: Mark Reid, Kym Lowry, Donna Mackenzie, Andrew Baron, Natalie Lehmann, John Aaskov, Farshad Guirakhoo, Thomas P MonathAbstract:Australian mosquitoes from which Japanese encephalitis virus (JEV) has been recovered (Culex annulirostris, Culex gelidus, and Aedes vigilax) were assessed for their ability to be infected with the ChimeriVax-JE vaccine, with yellow fever vaccine virus 17D (YF 17D) from which the backbone of ChimeriVax-JE vaccine is derived and with JEV-Nakayama. None of the mosquitoes became infected after being fed orally with 6.1 log(10) plaque-forming units (PFU)/mL of ChimeriVax-JE vaccine, which is greater than the peak viremia in vaccinees (mean peak viremia = 4.8 PFU/mL, range = 0-30 PFU/mL of 0.9 days mean duration, range = 0-11 days). Some members of all three species of mosquito became infected when fed on JEV-Nakayama, but only Ae. vigilax was infected when fed on YF 17D. The results suggest that none of these three species of mosquito are likely to set up secondary cycles of transmission of ChimeriVax-JE in Australia after feeding on a viremic vaccinee.
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experimental infection of Culex annulirostris Culex gelidus and aedes vigilax with a yellow fever japanese encephalitis virus vaccine chimera chimerivax tm je
Faculty of Health; Institute of Health and Biomedical Innovation, 2006Co-Authors: John Aaskov, Donna Mackenzie, Andrew Baron, Natalie Lehmann, Farshad Guirakhoo, Thomas P Monath, Kim Lowry, Mark ReidAbstract:Article also free to read on publisher website Australian mosquitoes from which Japanese encephalitis virus (JEV) has been recovered (Culex annulirostris, Culex gelidus, and Aedes vigilax) were assessed for their ability to be infected with the ChimeriVax-JE vaccine, with yellow fever vaccine virus 17D (YF 17D) from which the backbone of ChimeriVax-JE vaccine is derived and with JEV-Nakayama. None of the mosquitoes became infected after being fed orally with 6.1 log(10) plaque-forming units (PFU)/mL of ChimeriVax-JE vaccine, which is greater than the peak viremia in vaccinees (mean peak viremia = 4.8 PFU/mL, range = 0-30 PFU/mL of 0.9 days mean duration, range = 0-11 days). Some members of all three species of mosquito became infected when fed on JEV-Nakayama, but only Ae. vigilax was infected when fed on YF 17D. The results suggest that none of these three species of mosquito are likely to set up secondary cycles of transmission of ChimeriVax-JE in Australia after feeding on a viremic vaccinee.