scholarly journals Ross River virus - at the interface between humans, animals and the environment

2012 ◽  
Vol 33 (4) ◽  
pp. 160
Author(s):  
Abbey Potter ◽  
Michael D A Lindsay ◽  
John S MacKenzie
Keyword(s):  
Environmental Conditions ◽  
Convincing Evidence ◽  
Ross River Virus ◽  
Mosquito Vectors ◽  
Infection Rates ◽  
South West ◽  
Close Proximity ◽  
Vector Mosquito ◽  
Human Habitation ◽  
Vertebrate Hosts

Ross River virus (RRV) is the most common cause of mosquito-borne illness in Western Australians. The virus is maintained in nature principally via transmission between competent mosquito vectors and native (marsupial) vertebrate hosts, although humans are suspected of being amplifiers of RRV in some situations. The influence of prevailing environmental conditions on the ecology of RRV has been extensively documented. Indeed, monitoring of environmental variables, together with vector mosquito populations and infection rates with RRV, now provides effective early warning of elevated levels of RRV activity in several different regions of Australia. Serosurveys provide convincing evidence that western grey kangaroos (WGK; Macropus fuliginosus) are commonly infected with the virus in south-west coastal regions of Western Australia. There is also evidence of seroconversions in WGKs coinciding with outbreaks of human disease. Such outbreaks have been preceded by favourable environmental conditions for breeding of WGKs, presumably leading to an increase in numbers of non-immune individuals in the environment. More recently, GIS analyses of clusters of human cases of RRV has shown a relationship between proximity of residence to mosquito and WGK habitat and risk of RRV disease. These findings indicate that monitoring of seroprevalence to RRV in vertebrate hosts of RRV, such as the WGK, may assist in predicting outbreaks of RRV disease and for determining whether strategies to manage natural host populations in close proximity to human habitation may be worth further consideration.

scholarly journals A peridomestic population of the tsetse fly Glossina palpalis palpalis Robineau-Desvoidy, 1830 (Diptera: Glossinidae) at Kontagora town, Niger state, Nigeria

2004 ◽  
Vol 11 (4) ◽  
pp. 599-610 ◽  
Author(s):  
A. B. Ahmed
Keyword(s):  
Tsetse Fly ◽  
Glossina Palpalis Palpalis ◽  
Infection Rates ◽  
Wet Season ◽  
Abnormal Behaviour ◽  
The Public ◽  
Close Proximity ◽  
Reservoir Hosts ◽  
Glossina Palpalis ◽  
Wild Life

The present article considers some aspects of a peridomestic population of the tsetse fly Glossina palpalis palpalis Robineau-Desvoidy, 1830 in Kontagora, Nigeria. This situation characterizes an abnormal behaviour of the vector, and it is of significant epidemiological importance. Data on the ecology of this species were collected in 1995 and 1999. The results indicated that the species exists during both dry and wet seasons; approximately 30.0% of the catches were gorged with blood giving a MHS of 2.4, indicating a well-nourished population. Dissection of inseminated pars indicated pregnancy rates of approximately 30.0% and 70.0% in the dry and wet seasons and the presence of all 4 stages of pregnancy, suggesting that breeding occurs at both seasons. Longevity of flies was approximately 16 days in dry season and 25 days in the wet season. Overall results indicated that vector/host contact was high and the fly population has adapted and actively breeding in the area. Trypanosome infection rates of 18.2% consist of 1 brucei-type and 5 vivax-type infections. The public health implications of the close proximity of the wild natural reservoir hosts of the human T. b. gambiense Dutton, 1902 parasites at the Kainji Wild Life park is discussed.

Residency and movement dynamics of southern rock lobster (Jasus edwardsii) after a translocation event

2015 ◽  
Vol 66 (7) ◽  
pp. 623 ◽  
Author(s):  
Adrian Linnane ◽  
Shane Penny ◽  
Peter Hawthorne ◽  
Matthew Hoare
Keyword(s):  
Large Scale ◽  
South Australia ◽  
Rock Lobster ◽  
Directed Movement ◽  
Translocation Event ◽  
South West ◽  
Movement Dynamics ◽  
Close Proximity ◽  
Jasus Edwardsii ◽  
Almost All

Previous movement studies on the southern rock lobster (Jasus edwardsii) have all involved releasing tagged animals at the point of capture. In 2007, 5298 lobsters, in total, were tagged and translocated from an offshore site (>100-m depth) to two inshore sites (<20-m depth) in South Australia. After a period of 735 days, 510 (9.6%) had been recaptured. The majority of translocated lobsters were located within close proximity to the release points, with 306 (60%) having moved <5km. Of the remainder, 133 (26%) were recaptured within 5–10km, with a further 71 (14%) individuals having moved >10km. Movement patterns were highly directional in nature, with individuals consistently travelling in a south-west bearing, regardless of distance moved. In almost all cases, movement was from inshore to offshore sites, with female lobsters travelling significantly further (mean 5.66km ±6.41s.d.) than males (mean 5.02km ±9.66s.d.). The results are consistent with previous large-scale tagging studies of J. edwardsii, which indicated high residency levels but with occasional directed movement by some individuals.

Numerical and Experimental Tools for Offshore DP Operations

2011 ◽  
Author(s):  
Fabiano P. Rampazzo ◽  
Joa˜o Luis B. Silva ◽  
Daniel P. Vieira ◽  
Antonio L. Pacifico ◽  
Lazaro Moratelli Junior ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Experimental Tests ◽  
Coupled System ◽  
Coupled Analysis ◽  
Cfd Analysis ◽  
Maximum Condition ◽  
Commercial Code ◽  
Close Proximity ◽  
Fully Coupled ◽  
Two Bodies

DP crane vessel operation can be analyzed based on the uncoupled system or considering the fully coupled system. Parameters such as top-crane acceleration, thruster capability and vessel motions are evaluated for several environmental conditions. Numerical and experimental tools are used and the important result of this analysis is the maximum condition in such that the operation can be safely executed. Those operations are critical, since the vessel is kept in close proximity with other unit and large loads are transported in a pendulum configuration. A precise positioning of the crane-vessel is required, in order to avoid unsafe relative motions, as well as keep the load being transported on a stable position. The uncoupled analysis approach does not consider the influence of the other unit in the crane vessel. This paper presents a methodology for evaluating a DP crane vessel in the offshore operations (DP crane vessel, load being transported, mooring and assistance lines, platform) considering the fully coupled method based on integration of the in house codes with the commercial code WAMIT® system. The methodology is based on the integration of numerical and experimental tools. The dimensions of the transported modules and the proximity of the vessels change the behavior of the vessel motions and line tensions. So, a full nonlinear time domain simulator (TPN – Numerical Offshore Tank) is used to perform the coupled analysis of the system subjected to several environmental conditions, considering also the dynamics of the suspended load and the hydrodynamic interference between the bodies. In order to calibrate the numerical model, several experimental tests are performed such as wind tests with some positions of the crane, tests in towing tanks to evaluated the current effects, thrusters tests to calibrate DP algorithm and wave test with the two bodies. In some cases a complementary CFD analysis is requested in order to evaluate the current and wind shadow effect. Several alternative relative positions between the vessels can be evaluated. This methodology results a more accurate estimative of the system performance.

Distribution of schistosome genetic diversity within naturally infected Rattus rattus detected by RAPD markers

Parasitology ◽  
1996 ◽  
Vol 113 (6) ◽  
pp. 511-517 ◽  
Author(s):  
V. Barral ◽  
S. Morand ◽  
J. P. Pointier ◽  
A. Théron
Keyword(s):  
Genetic Diversity ◽  
Rapd Markers ◽  
Random Amplified Polymorphic Dna ◽  
Rattus Rattus ◽  
High Mobility ◽  
Genotypic Diversity ◽  
Vertebrate Host ◽  
Infection Rates ◽  
Snail Infection ◽  
Vertebrate Hosts

SUMMARYRandom amplified polymorphic DNA markers (RAPD) were used to visualize the genetic diversity within and between infrapopulations of Schistosoma mansoni recovered from the natural vertebrate host, Rattus rattus, trapped at an insular Guadeloupean focus. Phenotypes were characterized by the sex of the parasites and by 8 polymorphic markers generated by 3 primers. Among the 212 parasite individuals recovered from 10 infected rats, 78 genotypes were characterized. All the hosts naturally infected harboured multiple parasite genotypes with a maximum diversity of 28 genotypes/host. Phenotypic and genotypic diversity calculated by Shannon-Wiener's indices and Lynch and Milligan's estimators respectively is, on average, greater within than between hosts. Considering the very low snail infection rates observed in this focus and the rapid turnover of the vertebrate hosts, our results suggest that the high mobility of the vertebrate host and/or plurimiracidial snail infections could be factors responsible for parasite genetic diversity within hosts.

Identification of Site Frequencies from Building Records

2003 ◽  
Vol 19 (1) ◽  
pp. 1-23 ◽  
Author(s):  
M. Çelebi
Keyword(s):  
Additional Data ◽  
Simple Procedure ◽  
Free Field ◽  
Site Characterization ◽  
Convincing Evidence ◽  
Earthquake Response ◽  
Geological Structures ◽  
Spectral Analyses ◽  
Earthquake Records ◽  
Close Proximity

A simple procedure to identify site frequencies using earthquake response records from roofs and basements of buildings is presented. For this purpose, data from five different buildings are analyzed using only spectral analyses techniques. Additional data such as free-field records in close proximity to the buildings and site characterization data are also used to estimate site frequencies and thereby to provide convincing evidence and confirmation of the site frequencies inferred from the building records. Furthermore, simple code-formula is used to calculate site frequencies and compare them with the identified site frequencies from records. Results show that the simple procedure is effective in identification of site frequencies and provides relatively reliable estimates of site frequencies when compared with other methods. Therefore the simple procedure for estimating site frequencies using earthquake records can be useful in adding to the database of site frequencies. Such databases can be used to better estimate site frequencies of those sites with similar geological structures.

The distribution and genetic structure of Escherichia coli in Australian vertebrates: host and geographic effects

Microbiology ◽  
2003 ◽  
Vol 149 (12) ◽  
pp. 3575-3586 ◽  
Author(s):  
David M. Gordon ◽  
Ann Cowling
Keyword(s):  
Escherichia Coli ◽  
Body Mass ◽  
The Body ◽  
Ecological Niches ◽  
E Coli ◽  
Close Proximity ◽  
Host Diet ◽  
Group A ◽  
Human Habitation ◽  
The Tropics

Escherichia coli was isolated from more than 2300 non-domesticated vertebrate hosts living in Australia. E. coli was most prevalent in mammals, less prevalent in birds and uncommon in fish, frogs and reptiles. Mammals were unlikely to harbour E. coli if they lived in regions with a desert climate and less likely to have E. coli if they lived in the tropics than if they lived in semi-arid or temperate regions. In mammals, the likelihood of isolating E. coli from an individual depended on the diet of the host and E. coli was less prevalent in carnivores than in herbivores or omnivores. In both birds and mammals, the probability of isolating E. coli increased with the body mass of the host. Hosts living in close proximity to human habitation were more likely to harbour E. coli than hosts living away from people. The relative abundance of E. coli groups A, B1, B2 and D strains in mammals depended on climate, host diet and body mass. Group A strains were uncommon, but were isolated from both ectothermic and endothermic vertebrates. Group B1 strains could also be isolated from any vertebrate group, but were predominant in ectothermic vertebrates, birds and carnivorous mammals. Group B2 strains were unlikely to be isolated from ectotherms and were most abundant in omnivorous and herbivorous mammals. Group D strains were rare in ectotherms and uncommon in endotherms, but were equally abundant in birds and mammals. The results of this study suggest that, at the species level, the ecological niche of E. coli is mammals with hindgut modifications to enable microbial fermentation, or in the absence of a modified hindgut, E. coli can only establish a population in ‘large-bodied’ hosts. The non-random distribution of E. coli genotypes among the different host groups indicates that strains of the four E. coli groups may differ in their ecological niches and life-history characteristics.

scholarly journals Low-density genetically diverse natural Wolbachia infections in malaria vectors in Kayin state, Myanmar

2019 ◽  
Vol 4 ◽  
pp. 11
Author(s):  
Sunisa Sawasdichai ◽  
Victor Chaumeau ◽  
Tee Dah ◽  
Thithiworada Kulabkeeree ◽  
Ladda Kajeechiwa ◽  
...  
Keyword(s):  
Malaria Vectors ◽  
Human Landing Catch ◽  
Low Density ◽  
Mosquito Vectors ◽  
Infection Rates ◽  
Vector Species ◽  
Closely Related Species ◽  
Human Landing ◽  
Malaria Mosquitoes ◽  
Rrna Sequences

Background: Natural Wolbachia infections in malaria mosquitoes were recently reported in Africa, and negatively correlated with the development of Plasmodium falciparum in the vectors. The occurrence and effects of Wolbachia infections outside Africa have not been described and may have been underestimated. Methods: Mosquitoes were collected by human-landing catch during May and June 2017 in ten villages in Kayin state, Myanmar. Closely related species of malaria vectors were identified with molecular assays. Wolbachia infection rates were assessed with quantitative real-time PCR. Results: Low titer of Wolbachia DNA was detected in 13/370 samples in six malaria vector species. Phylogenetic analysis based on 16S rRNA sequences revealed a high diversity of Wolbachia strains and identified lineages different from those described in the African malaria mosquitoes. Conclusion: These low-density genetically diverse natural Wolbachia infections question the ecology and biology of Wolbachia-Anopheles interactions in Southeast Asia. Their effects on malaria transmission and mosquito vectors are yet to be determined.

scholarly journals TIR-Domain-Containing Adapter-Inducing Interferon-β (TRIF)-Dependent Antiviral Responses Protect Mice against Ross River Virus Disease

mBio ◽  
2022 ◽  
Author(s):  
Xiang Liu ◽  
Adam Taylor ◽  
Yee Suan Poo ◽  
Wern Hann Ng ◽  
Lara J. Herrero ◽  
...  
Keyword(s):  
Virus Disease ◽  
South Pacific ◽  
International Travel ◽  
Social Costs ◽  
Ross River Virus ◽  
Pacific Region ◽  
Mosquito Vectors ◽  
Interferon Β ◽  
Tir Domain ◽  
Antiviral Responses

RRV has been prevalent in the South Pacific region for decades and causes substantial economic and social costs. Though RRV is geographically restricted, a number of other alphaviruses have spread globally due to expansion of the mosquito vectors and increased international travel.

scholarly journals Interaction between parasite and vector for Malaria disease transmission-a review on Malaria

2016 ◽  
Vol 27 (2) ◽  
pp. 168-174
Author(s):  
M Mala ◽  
M Imam ◽  
K Hassan
Keyword(s):  
Malaria Transmission ◽  
Disease Transmission ◽  
Feeding Behaviour ◽  
Developmental Stages ◽  
Reproductive Behaviour ◽  
Blood Feeding ◽  
Insect Vector ◽  
Parasite Plasmodium ◽  
Vector Mosquito ◽  
Vertebrate Hosts

The parasite, Plasmodium needs an insect vector (mosquito) and a vertebrate host (human) to successful malaria transmission. The parasite use the vertebrate hosts for their asexual reproduction and insect host for sexual multiplication. In order to know the mechanism of disease transmission, knowledge about the possible interactions causes by the three components, vector, parasite and host is important. The mosquito feeding behaviour greatly contributes in the rate of malaria transmission. To assist the rate of transmission of malaria, the parasite, Plasmodium completes a complex developmental stage in the mosquito. In the mosquito the parasite, passes complex developmental stages and ensuing changes into three important forms of their life cycle: ookinete, oocyst and sporozoites. This review study concludes that, the interactions among vector, parasite and host in terms of reproductive behaviour and blood-feeding behaviour helps in transmitting malaria to the vertebrate hosts mainly, human being.Progressive Agriculture 27 (2): 168-174, 2016

Prevalence of neutralising antibodies to Barmah Forest, Sindbis and Trubanaman viruses in animals and humans in the south-west of Western Australia

2005 ◽  
Vol 53 (1) ◽  
pp. 51 ◽  
Author(s):  
Cheryl A. Johansen ◽  
John S. Mackenzie ◽  
David W. Smith ◽  
Michael D. A. Lindsay
Keyword(s):  
Western Australia ◽  
Sindbis Virus ◽  
The South ◽  
Neutralising Antibodies ◽  
Feral Pigs ◽  
Definitive Evidence ◽  
South West ◽  
Routine Surveillance ◽  
Human Sera ◽  
Vertebrate Hosts

A study was undertaken in the south-west of Western Australia to investigate potential vertebrate hosts of Barmah Forest virus (BFV), Sindbis virus (SINV) and Trubanaman virus (TRUV) following isolation of these viruses from mosquitoes collected during routine surveillance for arboviruses. Over 3000 animal and human sera collected between 1979 and 1995 were tested for the presence of neutralising antibodies to each of the viruses. The overall prevalence of antibodies to BFV, SINV and TRUV was 0.4%, 0.3% and 1.6%, respectively. Antibodies to BFV were detected only in quokkas (3.2%), horses (1.2%) and humans (0.9%). No definitive evidence of infection with BFV was detected in samples collected prior to 1992, supporting previous suggestions that BFV was introduced into the region after this time. Antibodies to SINV were detected in western native cats (16.7%), emus (4.5%), rabbits (0.8%) and horses (0.7%), and evidence of TRUV infection was most common in western grey kangaroos (21.1%), feral pigs (3.6%), rabbits (2.4%), foxes (2.3%), quokkas (1.6%) and horses (1.6%).

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