Salmonella-spedfic bacteriophages (BP) and competitive exclusion (CE) were used to reduce Salmonella colonization in experimentally infected chickens. A "cocktail" of distinct phage (i.e., phage showing different host ranges and inducing different types of plaques on Salmonella Typhimurium [ST] cultures) was developed. The killing activity of the selected BPs on ST cultures differed significantly, as determined in in vitro killing assays. BPs were administered orally to the chickens several days prior and after ST challenge but not simultaneously. BPs were readily isolated from the feces of the BP-treated chickens approximately 48 hr after administration. A CE product consisting of a defined culture of seven different microbial species was used either alone or in combination with BP treatment. CE was administered orally at hatch. Salmonella counts in intestine, ceca, and a pool of liver/spleen were evaluated in Salmonella-challenged chickens treated with BP or with BP and CE. In both trials 1 and 2, a beneficial effect of the phage treatment on weight gain performance was evident. A reduction in Salmonella counts was detected in cecum and ileum of BP-, CE-, and BP+CE-treated chickens as compared with nontreated birds. In trial 1, BP treatment reduced ST counts to marginal levels in the ileum and reduced counts sixfold in the ceca. A reduction of Salmonella counts with BP, CE, and BP+CE treatments was evident in chickens from trial 2. Both CE and BP treatments showed differences in the reduction of Salmonella counts after challenge between spedmens obtained at days 4 and 14 postchallenge in ceca, liver/spleen, and ileum. The preliminary data presented in this report show that isolation and characterization of Salmonella-specific BP is uncomplicated and feasible on a larger scale. Results indicate a protective effect of both Salmonella-specific BPs and a defined competitive exclusion product against Salmonella colonization of experimentally infected chickens. These results are encouraging for further work on the use of BP as an effective alternative to antibiotics to reduce Salmonella infections in poultry.

Oligolectic bees are specialists that collect pollen from one or a few closely related species of plants, while polylectic bees are generalists that collect pollen from both related and unrelated species of plants. Because of their more restricted range of floral hosts, it is expected that specialists persist in more isolated populations than do generalists. We present data on the population structure of two closely related bee species sampled from a super abundant floral host in the southern Atacama Desert. Pairwise comparisons of population subdivision over identical distances revealed that the specialist bee had significantly more differentiated populations in comparison to the generalist. Further, populations of the specialist had significantly less genetic variation, measured as observed and expected heterozgyosity, than those of the generalist. Our data support the hypothesis of decreased gene flow among populations of the specialist bee even at equivalent geographic distances. The resulting reductions in effective population size for specialists make them particularly prone to extinction due to both demographic and genetic reasons. Our findings have important implications for the conservation of bees and other specialist insects.

Protective immunity against avian influenza virus was elicited in chickens by single-dose in ovo vaccination with a non-replicating human adenovirus vector encoding an H5N9 avian influenza virus hemagglutinin. Vaccinated chickens were protected against both H5N1 (89% hemagglutinin homology; 68% protection) and H5N2 (94% hemagglutinin homology; 100% protection) highly pathogenic avian influenza virus challenges. Mass-administration of this bird flu vaccine can be streamlined with available robotic in ovo injectors. In addition, adenovirus-vectored vaccines can be produced rapidly and the safety margin of a non-replicating vector is superior to that of a replicating counterpart. Furthermore, this mode of vaccination is compatible with epidemiological surveys of natural avian influenza virus infections.

Oligolectic bees collect pollen from one or a few closely related species of plants, whereas polylectic bees visit a variety of flowers for pollen. Because of their more restricted range of host plants, it maybe expected that specialists exist in smaller, more isolated populations, with lower effective population sizes than generalists. Consequently, we hypothesized that oligolectic bees have reduced levels of genetic variation relative to related polylectic species. To test this hypothesis, we used five phylogenetically independent pairs of species in which one member was oligolectic and the other was polylectic. We assayed genetic variation in our species pairs at an average of 32 allozyme loci. Within each species pair, the oligolectic member had fewer polymorphic loci, lower average allelic richness, and lower average expected heterozygosity than its polylectic relative. Averaged over all species pairs, this corresponds to a 21% reduction in allelic richness, a 72% reduction in the proportion of polymorphic loci, and an 83% reduction in expected heterozygosity in specialists compared with generalists. Our data support the hypothesis of reduced effective population size in oligolectic bees and suggest that they may be more prone to extinction as a result. We suggest that in instances in which bee specialists are involved in mutually codependent relationships with their floral hosts, these mutualisms may be endangered for genetic and ecological reasons. Genética de la Conservación de Mutualismos Potencialmente en Peligro: Bajos Niveles de Variación Genética en Abejas Especialistas Versus GeneralistasResumen: Abejas oligolécticas colectan polen de una o varias especies de plantas cercanamente relacionadas, mientras que abejas polilécticas visitan una variedad de flores para polen. Debido a que su rango de plantas huésped es más restringido, puede esperarse que las especialistas existan en poblaciones más pequeñas y más aisladas, con menor tamaño poblacional efectivo, que las generalistas. Consecuentemente, planteamos la hipótesis de que abejas oligolécticas tienen niveles reducidos de variación genética en relación con especies polilécticas. Para probar esta hipótesis utilizamos cinco pares de especies filogenéticamente independientes en los que un miembro era oligoléctico y otro poliléctico. Analizamos la variación genética en nuestros pares de especies en un promedio de 32 loci de alozimas. En cada par de especies, el miembro oligoléctico tenía menos loci polimórficos, menor promedio de riqueza alélica y menor promedio de heterocigosidad esperada que su pariente poliléctico. Promediado en todos los pares de especies, esto corresponde a una reducción de #These two authors contributed equally to this paper.§Deceased. 196Conservation Genetics of Oligolectic Bees Packer et al.21% de la riqueza alélica, reducción de 72% en la proporción de loci polimórficos y una reducción de 83% en la heterocigosidad esperada en especialistas comparados con generalistas. Nuestros datos soportan la hipótesis de reducción en el tama...

A total of 100 free-living urban pigeons (Columba livia) were captured in the city of Santiago, Chile, in order to evaluate, for the ® rst time, their health status. Negligible antibody titres (1 to 3 log2) were detected in 22% of the birds against a strain of the paramyxovirus (PMV) serotype 1. No pigeons had antibodies against PMV serotype 7 and avian in¯uenza. Salmonella sp. belonging to serogroups B and D were isolated from the intestinal tract of three pigeons (3%). The protozoa Haemoproteus columbae, Plasmodium sp., and Leucocytozoon sp. were not detected in any pigeons. Trichomonas gallinae was detected in 11%, without observation of either clinical signs or gross pathological changes at necropsy. Sixty-seven percent of the birds showed the presence of the chewing lice Columbicola columbae and Campanulotes bidentatus compar, and 1% harboured the mite Laminosioptes cysticola. Seven species of nematodes were identi® ed. The frequency at which each species was detected was; Tetrameres sp. (14%), Capillaria annulata (1%), Capillaria columbae (11%), Capillaria obsignata (1%), Ascaridia columbae (5%), Dispharynx spiralis (2%), and Gongylonema ingluvicola (2%). The class Cestoda, found in one pigeon, was represented by the species Aporina delafondi. No trematodes were detected in the sampled birds.