scholarly journals Dispersing hemipteran vectors have reduced arbovirus prevalence

2014 ◽  
Vol 10 (4) ◽  
pp. 20140117 ◽  
Author(s):  
Amy T. Moore ◽  
Charles R. Brown

A challenge in managing vector-borne zoonotic diseases in human and wildlife populations is predicting where epidemics or epizootics are likely to occur, and this requires knowing in part the likelihood of infected insect vectors dispersing pathogens from existing infection foci to novel areas. We measured prevalence of an arbovirus, Buggy Creek virus, in dispersing and resident individuals of its exclusive vector, the ectoparasitic swallow bug ( Oeciacus vicarius ), that occupies cliff swallow ( Petrochelidon pyrrhonota ) colonies in western Nebraska. Bugs colonizing new colony sites and immigrating into established colonies by clinging to the swallows’ legs and feet had significantly lower virus prevalence than bugs in established colonies and those that were clustering in established colonies before dispersing. The reduced likelihood of infected bugs dispersing to new colony sites indicates that even heavily infected sites may not always export virus to nearby foci at a high rate. Infected arthropods should not be assumed to exhibit the same dispersal or movement behaviour as uninfected individuals, and these differences in dispersal should perhaps be considered in the epidemiology of vector-borne pathogens such as arboviruses.

2017 ◽  
Author(s):  
Charles R. Brown ◽  
Mary B. Brown ◽  
Peter Pyle ◽  
Michael A. Patten

2014 ◽  
Vol 281 (1781) ◽  
pp. 20140098 ◽  
Author(s):  
Neus Latorre-Margalef ◽  
Conny Tolf ◽  
Vladimir Grosbois ◽  
Alexis Avril ◽  
Daniel Bengtsson ◽  
...  

Data on long-term circulation of pathogens in wildlife populations are seldom collected, and hence understanding of spatial–temporal variation in prevalence and genotypes is limited. Here, we analysed a long-term surveillance series on influenza A virus (IAV) in mallards collected at an important migratory stopover site from 2002 to 2010, and characterized seasonal dynamics in virus prevalence and subtype diversity. Prevalence dynamics were influenced by year, but retained a common pattern for all years whereby prevalence was low in spring and summer, but increased in early autumn with a first peak in August, and a second more pronounced peak during October–November. A total of 74 haemagglutinin (HA)/neuraminidase (NA) combinations were isolated, including all NA and most HA (H1–H12) subtypes. The most common subtype combinations were H4N6, H1N1, H2N3, H5N2, H6N2 and H11N9, and showed a clear linkage between specific HA and NA subtypes. Furthermore, there was a temporal structuring of subtypes within seasons based on HA phylogenetic relatedness. Dissimilar HA subtypes tended to have different temporal occurrence within seasons, where the subtypes that dominated in early autumn were rare in late autumn, and vice versa. This suggests that build-up of herd immunity affected IAV dynamics in this system.


2009 ◽  
Vol 14 (12) ◽  
Author(s):  
J Ahmed ◽  
M Bouloy ◽  
O Ergonul ◽  
A. R. Fooks ◽  
J Paweska ◽  
...  

Arboviruses are arthropod-borne viruses, which include West Nile fever virus (WNFV), a mosquito-borne virus, Rift Valley fever virus (RVFV), a mosquito-borne virus, and Crimean-Congo haemorrhagic fever virus (CCHFV), a tick-borne virus. These arthropod-borne viruses can cause disease in different domestic and wild animals and in humans, posing a threat to public health because of their epidemic and zoonotic potential. In recent decades, the geographical distribution of these diseases has expanded. Outbreaks of WNF have already occurred in Europe, especially in the Mediterranean basin. Moreover, CCHF is endemic in many European countries and serious outbreaks have occurred, particularly in the Balkans, Turkey and Southern Federal Districts of Russia. In 2000, RVF was reported for the first time outside the African continent, with cases being confirmed in Saudi Arabia and Yemen. This spread was probably caused by ruminant trade and highlights that there is a threat of expansion of the virus into other parts of Asia and Europe. In the light of global warming and globalisation of trade and travel, public interest in emerging zoonotic diseases has increased. This is especially evident regarding the geographical spread of vector-borne diseases. A multi-disciplinary approach is now imperative, and groups need to collaborate in an integrated manner that includes vector control, vaccination programmes, improved therapy strategies, diagnostic tools and surveillance, public awareness, capacity building and improvement of infrastructure in endemic regions.


2020 ◽  
pp. 291-294
Author(s):  
Nikanorova ◽  
Kozlov

The article considers the issues of carriage by small mammals of dangerous zoonotic diseases: leptospirosis, tularemia, hantaviruses. Data on the detection of antigens to pathogens in the districts of the Kaluga region are presented. As you know, small mammals are the main link in maintaining zoonotic natural focal diseases. The larval phases of ixodic ticks, mosquitoes and other parasitic arthropods prefer to feed on the blood of mouse rodents, which contributes to the spread of vector-borne infections and infestations. The following species of mouse rodents are found in the Kaluga Region: small forest mouse (Apodemus uralensis), gray vole, red vole (Myodes glareolus), field mouse (Apodemus agrarius), gray rat (Rattus norvegicus), and house mouse (Mus musculus). In natural biotopes, field species prevail in number: field mouse, gray vole, red vole. In the Kaluga region, antigens for tularemia, hantaviruses, and leptospirosis were found in small mammals in 4.9–9.4% of the studied animals on average per year. Of particular concern are the city of Kaluga, Borovsky, Babyninsky, Yukhnovsky, Ulyanovsk, Medynsky, Maloyaroslavetsky, Meshchovsky, Peremyshlsky, Kozelsky, Dzerzhinsky and Ulyanovsk districts. The data obtained indicate the stationarity of these diseases in the territory of the Kaluga region.


1979 ◽  
Vol 111 (6) ◽  
pp. 713-719 ◽  
Author(s):  
G.P. Holland

AbstractThree new species of fleas are described, two of the family HYSTRICHOPSYLLIDAE Tiraboschi 1904 (Nearctopsylla grahami n. sp. and Rhadinopsylla (Micropsylla) rauschi n. sp.) and one of the family CERATOPHYLLIDAE Dampf 1908 (Ceratophyllus calderwoodi n. sp,). N. grahami is known only from western Ontario where it has been collected from marten, Martes a. americana. R. (M.) rauschi was collected from deer mice, Peromyscus maniculatus osgoodi, in southwestern Saskatchewan. C. calderwoodi was collected from a nest of cliff swallow, Petrochelidon pyrrhonota, in eastern New Brunswick.


2012 ◽  
Vol 279 (1737) ◽  
pp. 2354-2362 ◽  
Author(s):  
Luigi Sedda ◽  
Heidi E. Brown ◽  
Bethan V. Purse ◽  
Laura Burgin ◽  
John Gloster ◽  
...  

The 2006 bluetongue (BT) outbreak in northwestern Europe had devastating effects on cattle and sheep in that intensively farmed area. The role of wind in disease spread, through its effect on Culicoides dispersal, is still uncertain, and remains unquantified. We examine here the relationship between farm-level infection dates and wind speed and direction within the framework of a novel model involving both mechanistic and stochastic steps. We consider wind as both a carrier of host semio-chemicals, to which midges might respond by upwind flight, and as a transporter of the midges themselves, in a more or less downwind direction. For completeness, we also consider midge movement independent of wind and various combinations of upwind, downwind and random movements. Using stochastic simulation, we are able to explain infection onset at 94 per cent of the 2025 affected farms. We conclude that 54 per cent of outbreaks occurred through (presumably midge) movement of infections over distances of no more than 5 km, 92 per cent over distances of no more than 31 km and only 2 per cent over any greater distances. The modal value for all infections combined is less than 1 km. Our analysis suggests that previous claims for a higher frequency of long-distance infections are unfounded. We suggest that many apparent long-distance infections resulted from sequences of shorter-range infections; a ‘stepping stone’ effect. Our analysis also found that downwind movement (the only sort so far considered in explanations of BT epidemics) is responsible for only 39 per cent of all infections, and highlights the effective contribution to disease spread of upwind midge movement, which accounted for 38 per cent of all infections. The importance of midge flight speed is also investigated. Within the same model framework, lower midge active flight speed (of 0.13 rather than 0.5 m s −1 ) reduced virtually to zero the role of upwind movement, mainly because modelled wind speeds in the area concerned were usually greater than such flight speed. Our analysis, therefore, highlights the need to improve our knowledge of midge flight speed in field situations, which is still very poorly understood. Finally, the model returned an intrinsic incubation period of 8 days, in accordance with the values reported in the literature. We argue that better understanding of the movement of infected insect vectors is an important ingredient in the management of future outbreaks of BT in Europe, and other devastating vector-borne diseases elsewhere.


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