Article

Puzzling Decline of U.S. Bees Linked to Virus From Australia

Science (Impact Factor: 33.61). 10/2007; 317(5843):1304-5. DOI: 10.1126/science.317.5843.1304
Source: PubMed

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    • "Epidemics are usually presumed to be caused by single pathogens, a premise that may in some circumstances be overly simplistic. Temporal and spatial convergence of several infectious agents under environmental conditions that favor their transmission and propagation could create a ''perfect storm'' of pathogens, resulting in significantly greater mortality, as was suspected in the widespread collapse of honeybee colonies [1]. With global warming, there is considerable concern that ecological patterns of disease will be altered [2], as has occurred with the recent high mortality epidemics in amphibia[3] and corals [4]. "
    [Show abstract] [Hide abstract] ABSTRACT: Extreme climatic conditions may alter historic host-pathogen relationships and synchronize the temporal and spatial convergence of multiple infectious agents, triggering epidemics with far greater mortality than those due to single pathogens. Here we present the first data to clearly illustrate how climate extremes can promote a complex interplay between epidemic and endemic pathogens that are normally tolerated in isolation, but with co-infection, result in catastrophic mortality. A 1994 canine distemper virus (CDV) epidemic in Serengeti lions (Panthera leo) coincided with the death of a third of the population, and a second high-mortality CDV epidemic struck the nearby Ngorongoro Crater lion population in 2001. The extent of adult mortalities was unusual for CDV and prompted an investigation into contributing factors. Serological analyses indicated that at least five "silent" CDV epidemics swept through the same two lion populations between 1976 and 2006 without clinical signs or measurable mortality, indicating that CDV was not necessarily fatal. Clinical and pathology findings suggested that hemoparsitism was a major contributing factor during fatal epidemics. Using quantitative real-time PCR, we measured the magnitude of hemoparasite infections in these populations over 22 years and demonstrated significantly higher levels of Babesia during the 1994 and 2001 epidemics. Babesia levels correlated with mortalities and extent of CDV exposure within prides. The common event preceding the two high mortality CDV outbreaks was extreme drought conditions with wide-spread herbivore die-offs, most notably of Cape buffalo (Syncerus caffer). As a consequence of high tick numbers after the resumption of rains and heavy tick infestations of starving buffalo, the lions were infected by unusually high numbers of Babesia, infections that were magnified by the immunosuppressive effects of coincident CDV, leading to unprecedented mortality. Such mass mortality events may become increasingly common if climate extremes disrupt historic stable relationships between co-existing pathogens and their susceptible hosts.
    Full-text · Article · Feb 2008 · PLoS ONE
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    • "Mass mortality of honeybees (Apis mellifera) is one of the most serious problems that beekeepers and dependent industries face worldwide. A graphic example is the widely publicised economic, social and political upheaval caused by the extensive colony collapse among migratory beekeepers in the USA (Cox Foster et al., 2007; Stokstad, 2007a; 2007b) and similar colony collapses and agricultural disruption during the previous century (Beuhne, 1910; Wilson and Menapace, 1979; Oertel, 1965; Foote, 1966; Rennie, 1921; Bailey, 1964; Goodacre, 1943). "
    [Show abstract] [Hide abstract] ABSTRACT: Mortality of honeybees is a serious problem that beekeepers have to face periodically in Jordan and worldwide. The presence of honeybee viruses, in addition to other pathogens and parasites may be one of its possible causes. In this work, individual bee samples from Ajlon area of Jordan were screened for six honey bee viruses using RT-PCR and specific primers. Acute Bee Paralysis Virus (ABPV), Sac Brood Virus (SBV) and Deformed Wing Virus (DWV) were detected in the samples, while Black Queen Cell Virus (BQCV), Chronic Bee Paralysis Virus (CBPV) and Kashmir Bee Virus (KBV) were not detected. This is the first report of the detection of bee viruses in Jordan utilizing molecular techniques.
    Full-text · Article · Jan 2008
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    [Show abstract] [Hide abstract] ABSTRACT: Canine distemper virus (CDV) is thought to have caused several fatal epidemics in canids within the Serengeti-Mara ecosystem of East Africa, affecting silver-backed jackals (Canis mesomelas) and bat-eared foxes (Otocyon megalotis) in 1978 (ref. 1), and African wild dogs (Lycaon pictus) in 1991 (refs 2, 3). The large, closely monitored Serengeti lion population was not affected in these epidemics. However, an epidemic caused by a morbillivirus closely related to CDV emerged abruptly in the lion population of the Serengeti National Park, Tanzania, in early 1994, resulting in fatal neurological disease characterized by grand mal seizures and myoclonus; the lions that died had encephalitis and pneumonia. Here we report the identification of CDV from these lions, and the close phylogenetic relationship between CDV isolates from lions and domestic dogs. By August 1994, 85% of the Serengeti lion population had anti-CDV antibodies, and the epidemic spread north to lions in the Maasai Mara National reserve, Kenya, and uncounted hyaenas, bat-eared foxes, and leopards were also affected.
    Full-text · Article · Mar 1996 · Nature
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