Publications

Culicoides biting midges (Diptera: Ceratopogonidae) vector a wide variety of internationally important arboviral pathogens of livestock and represent a widespread biting nuisance. This study investigated the influence of landscape, host and remotely-sensed climate factors on local abundance of livestock-associated species in Scotland, within a hierarchical generalized linear model framework. The Culicoides obsoletus group and the Culicoides pulicaris group accounted for 56% and 41%, respectively, of adult females trapped. Culicoides impunctatus Goetghebuer and C. pulicaris s.s. Linnaeus were the most abundant and widespread species in the C. pulicaris group (accounting for 29% and 10%, respectively, of females trapped). Abundance models performed well for C. impunctatus, Culicoides deltus Edwards and Culicoides punctatus Meigen (adjusted R2: 0.590.70), but not for C. pulicaris s.s. (adjusted R2: 0.36) and the C. obsoletus group (adjusted R2: 0.08). Local-scale abundance patterns were best explained by models combining host, landscape and climate factors. The abundance of C. impunctatus was negatively associated with cattle density, but positively associated with pasture cover, consistent with this species' preference in the larval stage for lightly grazed, wet rush pasture. Predicted abundances of this species varied widely among farms even over short distances (less than a few km). Modelling approaches that may facilitate the more accurate prediction of local abundance patterns for a wider range of Culicoides species are discussed.

The genus Culicoides (Diptera: Ceratopogonidae) contains important vectors of animal and human diseases, including bluetongue, African horse sickness and filariosis. A major outbreak of bluetongue occurred in mainland Portugal in 2004, forty eight years after the last recorded case. A national Entomological Surveillance Plan was initiated in mainland Portugal, Azores and the Madeira archipelagos in 2005 in order to better understand the disease and facilitate policy decisions. During the survey, the most prevalent Culicoides species in mainland Portugal was C. imicola (75.3%) and species belonging to the Obsoletus group (6.5%). The latter were the most prevalent in Azores archipelago, accounting for 96.7% of the total species identified. The Obsoletus group was further characterized by multiplex Polymerase Chain Reaction to species level showing that only two species of this group were present: C. obsoletus sensu strictu (69.6%) and C. scoticus (30.4%). Nine species of Culicoides were detected for the first time in mainland Portugal: C. alazanicus, C. bahrainensis, C. deltus, C. lupicaris, C. picturatus, C. santonicus, C. semimaculatus, C. simulator and C. subfagineus. In the Azores, C. newsteadi and C. circumscriptus were identified for the first time from some islands, and bluetongue vectors belonging to the Obsoletus group (C. obsoletus and C. scoticus) were found to be widespread.

Two novel picornaviruses were serendipitously identified in apparently healthy young domestic animals-cattle (Bos taurus) and, subsequently, sheep (Ovis aries)-in Hungary during 2008 and 2009. Complete genome sequencing and comparative analysis showed that the two viruses are related to each other and have identical genome organizations, VPg + 5' UTRIRES-II[L/1A-1B-1C-1D-2A(NPG)down arrow(P)/2B-2C/3A-3B(VPg)-3C(pro)-3D(pol)] 3' UTR-poly(A). We suggest that they form two novel viral genotypes/serotypes, bovine hungarovirus 1 (BHuV-1; GenBank accession number JQ941880) and ovine hungarovirus 1 (OHuV-1; GenBank accession number HM153767), which may belong to a potential novel picornavirus genus in the family Picornaviridae. The genome lengths of BHuV-1 and OHuV-1 are 7,583 and 7,588 nucleotides, each comprising a single open reading frame encoding 2,243 and 2,252 amino acids, respectively. In the 5' untranslated regions (5' UTRs), both hungaroviruses are predicted to have a type II internal ribosome entry site (IRES). The nucleotide sequence and the secondary RNA structure of the hungarovirus IRES core domains H-I-J-K-L are highly similar to that of human parechovirus (HPeV) (genus Parechovirus), especially HPeV-3. However, in the polyprotein coding region, the amino acid sequences are more closely related to those of porcine teschoviruses (genus Teschovirus). Hungaroviruses were detected in 15% (4/26) and 25% (4/16) of the fecal samples from cattle and sheep, respectively. This report describes the discovery of two novel picornaviruses in farm animals, cattle and sheep. The mosaic genetic pattern raises the possibility that hungaroviruses, human parechoviruses, and porcine teschoviruses may be linked to each other by modular recombination of functional noncoding RNA elements.

During the early phase of the 2009 influenza pandemic, attempts were made to contain the spread of the virus. Success of reactive control measures may be compromised if the proportion of transmission that occurs before overt clinical symptoms develop is high. In this study we investigated the timing of transmission of an early prototypic strain of pandemic H1N1 2009 influenza virus in the ferret model. Ferrets are the only animal model in which this can be assessed because they display typical influenza-like clinical signs including fever and sneezing after infection. We assessed transmission from infected animals to sentinels that were placed either in direct contact or in adjacent cages, the latter reflecting the respiratory droplet (RD) transmission route. We found that pre-symptomatic influenza transmission occurred via both contact and respiratory droplet exposure before the earliest clinical sign, fever, developed. Three of 3 animals exposed in direct contact between day 1 and 2 after infection of the donor animals became infected, and 2/3 of the animals exposed at this time period by the RD route acquired the infection, with the third animal becoming seropositive indicating either a low level infection or significant exposure. Moreover, this efficient transmission did not temporally correlate with respiratory symptoms, such as coughs and sneezes, but rather with the peak viral titre in the nose. Indeed respiratory droplet transmission did not occur late in infection, even though this was when sneezing and coughing were most apparent. None of the 3 animals exposed at this time by the RD route became infected and these animals remained seronegative at the end of the experiment. These data have important implications for pandemic planning strategies and suggest that successful containment is highly unlikely for a human-adapted influenza virus that transmits efficiently within a population.