Search

Seasonality in infectious disease prevalence is predominantly attributed to changes in exogenous risk factors. For vectored pathogens, high abundance, activity, and/or diversity of vectors can exacerbate disease risk for hosts. Conversely, many host defenses, particularly immune responses, are seasonally variable. Seasonality in host defenses has been attributed, in part, to the proximate (i.e., metabolic) and ultimate (i.e., reproductive fitness) costs of defense. In this study, our goal was to discern whether any seasonality is observable in how a common avian host, the house sparrow (Passer domesticus), copes with a common zoonotic arbovirus, the West Nile virus (WNV), when hosts are studied under controlled conditions. We hypothesized that if host biorhythms play a role in vector-borne disease seasonality, birds would be most vulnerable to WNV when breeding and/or molting (i.e., when other costly physiological activities are underway) and thus most transmissive of WNV at these times of year (unless birds died from infection). Overall, the results only partly supported our hypothesis. Birds were most transmissive of WNV in fall (after their molt is complete and when WNV is most prevalent in the environment), but WNV resistance, WNV tolerance, and WNV-dependent mortality did not vary among seasons. These results collectively imply that natural arboviral cycles could be partially underpinned by endogenous physiological changes in hosts. However, other disease systems warrant study, as this result could be specific to the nonnative and highly commensal nature of the house sparrow or a consequence of the relative recency of the arrival of WNV to the United States. [ABSTRACT FROM AUTHOR]

Invasive birds cause damage to economies, natural resources, and human safety across the globe. In the United States, rock doves (Columba livia), Eurasian collared doves (Streptopelia decaocto), rose-ringed parakeets (Psittacula krameri), monk parakeets (Myiopsitta monachus), common mynas (Acridotheres tristis), European starlings (Sturnus vulgaris), and house sparrows (Passer domesticus) are among the invasive and often harmful small-bodied birds inhabiting periurban habitats. The destructive nature of these species warrants a review of methods to reduce or eradicate populations along with methods to reduce damage when population eradication cannot be achieved. We reviewed damage management literature from these species' native and introduced ranges. Additionally, we used the behavior and ecology of these species to inform tool recommendations and potential efficacy under various damage scenarios, while being sensitive to cultural preferences and location of implementation (residential, commercial, and agricultural). Although this review focuses on invasive birds in the United States, it is applicable to other pest species across the globe. Our review highlights areas where research is needed to validate promising damage management methods (lethal control, fertility control, habitat modification, exclusionary methods, frightening devices, and chemical repellents). Where birds are invasive, integrated pest management techniques should focus on eradication or population reduction (toxicants, shooting, and trapping) to keep populations at levels where nonlethal tools can reduce damage. We acknowledge the efficacy of an eradication campaign depends on biological, environmental, and economic factors, along with social license for lethal removal. We recommend integrated pest management strategies including lethal and nonlethal tools specific to the damage problem. Sustained efforts to reduce invasive populations should be used along with integrated deterrent strategies for short-term damage relief. [ABSTRACT FROM AUTHOR]

Summary: European starlings (Sturnus vulgaris), house sparrows (Passer domesticus) and rock pigeons (Columba livia) are all wild birds commonly found in large numbers in and around human dwellings and domestic livestock operations. This study evaluated the susceptibility of these species to three strains of highly pathogenic avian influenza virus (HP AIV) clade 2.3.4.4 isolated in the U.S.. Experimental infection of European starlings and rock pigeons did not result in any overt signs attributable to AIV infection and no virus shedding was detected from the oral and cloacal routes. House sparrows shed by the oral route and exhibited limited mortality. Individuals from all three species seroconverted following infection. These data suggest that none of these birds are a likely potential bridge host for future HP AIV outbreaks but that their seroconversion may be a useful surveillance tool for detection of circulating H5 HP AIV. [ABSTRACT FROM AUTHOR]

Arthropod-borne viruses (arboviruses) threaten the health of humans, livestock, and wildlife. West Nile virus (WNV), the world's most widespread arbovirus, invaded the United States in 1999 and rapidly spread across the county. Although the ecology of vectors and hosts are key determinants of WNV prevalence across landscapes, the factors shaping local vector and host populations remain unclear. Here, we used spatially-explicit models to evaluate how three land-use types (orchards, vegetable/forage crops, natural) and two climatic variables (temperature, precipitation) influence the prevalence of WNV infections and vector/host distributions at landscape and local spatial scales. Across landscapes, we show that orchard habitats were associated with greater prevalence of WNV infections in reservoirs (birds) and incidental hosts (horses), while increased precipitation was associated with fewer infections. At local scales, orchard habitats increased the prevalence of WNV infections in vectors (mosquitoes) and the abundance of mosquitoes and two key reservoir species, the American robin and the house sparrow. Thus, orchard habitats benefitted WNV vectors and reservoir hosts locally, creating focal points for the transmission of WNV at landscape scales in the presence of suitable climatic conditions. [ABSTRACT FROM AUTHOR]

Presents a study that analyzed variations in the sex ratio patterns of house sparrows in Lexington, Kentucky. Investigation of the sex ratio within and among years; Examination of within-season patterns in sex ratio; Correlation between male and female characteristics and sex ratio.

Presents a study which compared predation events and predators of Japanese Quail and smaller House Sparrow eggs in paired, ground nests in several forest stands in Massachusetts. Methodology; Results; Discussion.