Domestic dog demographics and estimates of canine vaccination coverage in a rural area of Zambia for the elimination of rabies

BackgroundAn estimated 75% or more of the human rabies cases in Africa occur in rural settings, which underscores the importance of rabies control in these areas. Understanding dog demographics can help design strategies for rabies control and plan and conduct canine mass vaccination campaigns effectively in African countries.Methodology/Principal findingsA cross-sectional survey was conducted to investigate domestic dog demographics in Kalambabakali, in the rural Mazabuka District of Zambia. The population of ownerless dogs and the total achievable vaccination coverage among the total dog population was estimated using the capture-recapture-based Bayesian model by conducting a canine mass vaccination campaign. This study revealed that 29% of the domestic dog population was under one year old, and 57.7% of those were under three months old and thus were not eligible for the canine rabies vaccination in Zambia. The population growth was estimated at 15% per annum based on the cross-sectional household survey. The population of ownerless dogs was estimated to be small, with an ownerless-to-owned-dog ratio of 0.01–0.06 in the target zones. The achieved overall vaccination coverage from the first mass vaccination was estimated 19.8–51.6%. This low coverage was principally attributed to the owners’ lack of information, unavailability, and dog-handling difficulties. The follow-up mass vaccination campaign achieved an overall coverage of 54.8–76.2%.Conclusions/SignificanceThis paper indicates the potential for controlling canine rabies through mass vaccination in rural Zambia. Rabies education and responsible dog ownership are required to achieve high and sustainable vaccination coverage. Our findings also propose including puppies below three months old in the target population for rabies vaccination and emphasize that securing an annual enforcement of canine mass vaccination that reaches 70% coverage in the dog population is necessary to maintain protective herd immunity.     

Complete nucleotide sequence of the <Emphasis Type="Italic">Cryptomeria japonica</Emphasis>D. Don. chloroplast genome and comparative chloroplast genomics: diversified genomic structure of coniferous species

Background  

The recent determination of complete chloroplast (cp) genomic sequences of various plant species has enabled numerous comparative analyses as well as advances in plant and genome evolutionary studies. In angiosperms, the complete cp genome sequences of about 70 species have been determined, whereas those of only three gymnosperm species, Cycas taitungensis, Pinus thunbergii, and Pinus koraiensis have been established. The lack of information regarding the gene content and genomic structure of gymnosperm cp genomes may severely hamper further progress of plant and cp genome evolutionary studies. To address this need, we report here the complete nucleotide sequence of the cp genome of Cryptomeria japonica, the first in the Cupressaceae sensu lato of gymnosperms, and provide a comparative analysis of their gene content and genomic structure that illustrates the unique genomic features of gymnosperms.     

Univoltine and bivoltine life cycles in insects: A model with density-dependent selection

Selection for univoltine and bivoltine life cycles in insects under resource-limited but favourable temperature conditions is analyzed with a difference equation model including density-dependent population dynamics based on the conceptual framework of an evolutionarily stable strategy. The model predicts that the bivoltine type can spread in a univoltine population when the fraction of density-independent rate of annual increase by producing a second generation exceeds the survival rate during diapause of the univoltine type, but monopoly of the bivoltine type is not possible unless it attains an equilibrium population density exceeding that of the univoltine type. The applicability of the model prediction in explaining the occurrence of a partial bivoltine cycle in predominantly univoltine population in the temperate zones is discussed.     

Marriage season, promptness of successful pregnancy and first-born sex ratio in a historical natural fertility population – evidence for sex-dependent early pregnancy loss?

 We investigated population-based vital records of the seventeenth and eighteenth century French Canadian population to assess the effects of marriage season on the outcome of the first births under natural fertility conditions (n=21,698 marriages). Promptness of the first successful conception after marriage differed according to marriage season; the proportion of marriages with a marriage-first birth interval of 8.0–10.0 months was lowest (34%) for marriages in August–October (P=0.001). Although the male/female sex ratio of the babies born with an interval of 8.0–10.0 months was generally higher (1.10) than those with an interval of 10.0–24.0 months (1.05), the marriages in August–October resulted in a significantly reduced sex ratio (0.96) among only the prompt conceptions (P=0.026). We discuss whether this seasonal reduction of the sex ratio could be partly explained by a clustered pregnancy loss of male zygotes in early pregnancy. Received: 5 January 1998 / Accepted: 9 September 1998     

Calcium sulfate and calcium carbonate as root-knot-nematode attractants and possible trap materials to protect crop plants

Root-knot nematodes (RKNs, genus Meloidogyne) are a class of plant parasites that seek out and infect the roots of many plant species. The identification of RKN attractants can be used in agriculture in conjunction with nematode-trapping technology to redirect RKN movements and eventually reduce their prevalence in the field. Here, we discovered that some commercial silica gels can attract nematodes. Silica gels that attract nematodes contain calcium sulfate. Calcium sulfate and calcium carbonate showed strong nematode attraction properties. When plant seeds were surrounded by calcium sulfate or calcium carbonate, nematodes were not attracted to the plant seeds. We propose that calcium sulfate and calcium carbonate can be used in agriculture as a novel material to trap RKN.     

Effects of capacity on resource input and the aquatic metazoan community structure in phytotelmata

Aquatic metazoan communities in treeholes and bamboo stumps were studied on Tsushima Island, Japan, in March and June in relation to the habitat size and the resouce amount. The amount of leaf detritus increased with an increase in the capacity (volume) of the phytotelma. The input rate of leaves depended upon the opening area of the phytotelma. Twenty-one metazoan inhabitant taxa consisted of 17 dipteran saprophages, a helodid beetle larva, a nematoda, a naidid, and a predator,Toxorhynchites towadensis mosquito larva. Treeholes harbored 17 taxa and bamboo stumps 20; 16 taxa were common in both phytotelmata. The number of taxa and the biomass of metazoa per phytotelma was positively correlated with the capacity. The densities of dominant saprophages such as helodid, chironomid, andCulicoides larvae were positively correlated with the capacity of phytotelmata, and the variation in their abundance contributed much to the variation in the species composition in individual phytotelmata. With an increase in capacity, treeholes harbored more helodids andCulicoides, whereas bamboo stumps harbored more chironomids andDasyhelea. Thus, the amount of resource, species richness and biomass per phytotelma largely depended upon the capacity, and the difference in community structure between treeholes and bamboo stumps was attributable to the differential colonization patterns of different taxa.