The total contact rates (TCRs) between mosquito vectors and their potential hosts have a serious impact on disease transmission dynamics. Culex pipiens (sensu stricto) (s.s.) is considered the main ...vector of the West Nile Virus (WNV) in Europe and birds are the reservoir hosts. The results of our previous study showed that WNV seroreactors are significantly more prevalent among raptors compared to a range of other wild avian groups. The current study aims to assess the role of bird type (raptor vs others) and bird size on mosquito feeding preferences in a free-choice experiment using bird-baited traps.
From July to September 2014, a battery of six bird-baited traps was operated in twelve mosquito capture sessions. Eight bird species, belonging to five different orders, including raptors, were used. After each session, the trapped mosquitoes were collected and identified using standard keys. Two sets of independent generalized linear mixed models (GLMM) were used to assess mosquito vector feeding preferences (MFp) among different bird species and types.
A total of 304 mosquitoes belonging to seven taxa were collected, C. pipiens being by far the most abundant (84.2 % of the total mosquito catch). Most C. pipiens were engorged (83.59 %). The selected model showed that 25.6 % of the observed variability of MFp is explained by the interaction between bird size and bird type, with C. pipiens preferring to feed on large birds, especially raptors. The proportion of engorged mosquitoes was 1.9-fold higher in large (22.88 %; range 0-42 %) than in medium-sized raptors (11.71 %; range 0-33 %), and was nearly the same in medium-sized (9.08 %; range 0-26 %) and large (8.5 %; 6-24 %) non-raptor species.
Culex pipiens showed an obvious preference for large raptors, which concurs with the higher seroprevalence to WNV in our previous study. The appreciable feeding by C. pipiens on large raptors makes them useful alternative sentinels to poultry for WNV surveillance. Thus, wildlife parks and rehabilitation centers can contribute to surveillance efforts to a greater extent.
Infectious keratoconjunctivitis (IKC) is a contagious eye disease primarily caused by Mycoplasma conjunctivae in domestic and wild Caprinae. Chlamydophila species have also been detected in ruminants ...with IKC. The objectives of this study are to investigate the ocular infection of M. conjunctivae and Chlamydiaceae and assess its interaction in relation to IKC in sheep and goats from remote communities around the Central Karakoram National Park in Pakistan, performing a combination of cross‐sectional and case–control study design. Mostly asymptomatic and endemic infections of M. conjunctivae and Chlamydiaceae were found in sheep (19.3 per cent and 4.5 per cent, respectively) and goats (9.5 per cent and 1.9 per cent, respectively) from all communities, assessed by qPCR. Prevalence significantly differed between species only for M. conjunctivae (P=0.0184), which was also more prevalent in younger sheep (P<0.01). Chlamydophila pecorum was identified by sequencing and was related with IKC only when coinfection with M. conjunctivae occurred, which suggest a synergic interaction. Cluster analysis of M. conjunctivae strains revealed higher diversity of strains than expected, evidenced interspecific transmission and suggested a higher local livestock trade than previously assumed. These results highlight the widespread occurrence of M conjunctivae in sheep worldwide and its implications for wildlife should be assessed from a conservation perspective.
•WNV and USUV circulation has been demonstrated in wild birds in Northwest Italy.•WNV antibodies were more prevalent (p<0.001) in trans-Saharan migrants birds.•Antibody titers were slightly higher to ...WNV than USUV.•Ringing and rehabilitation organizations had a critical role during this study.
Usutu virus (USUV) and West Nile virus (WNV) are emerging pathogens that can cause neurological disease in humans. From March 2012 to June 2013, a sero-survey on wild birds was carried out to investigate the circulation of both viruses in Northwest (NW) Italy. Samples belonging to 47 different bird species have been collected using a volunteer based network and a wildlife rehabilitation center. Four of 297 serum samples had neutralizing antibodies against USUV (P=1.34%, IC 95% 0.36–3.4), while 10 of 233 samples tested positive for WNV (P=4.29%, IC 95% 2.07–7.75). Neutralizing antibodies for WNV were significantly more prevalent (p<0.001) in trans-Saharan migrants (P=21%, IC 95% 9.55–37.3) than in resident and short-distance birds, but no migratory habit-related differences were found for USUV. Antibodies in resident bird species suggest that both viruses are circulating in NW Italy.
To assess the potential role of ticks as carriers of West Nile virus (WNV) and Usutu virus (USUV), we tested 1721 ticks from 379 wild birds in Northwestern Italy between 2012 and 2014. Ticks were ...analyzed in pools using a pan-flavivirus real-time RT-PCR and positive pools were subjected to RT-PCR for USUV and WNV genome detection. All the tested samples resulted negative, suggesting that Ixodes spp. ticks, at least in our study area, are not competent vectors and not even exploitable sentinels for USUV and WNV.
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