44
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Population genetic analysis and sub-structuring of Theileria parva in the northern and eastern parts of Zambia

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Background

          Theileriosis, caused by Theileria parva, is an economically important disease in Africa. It is a major constraint to the development of the livestock industry in some parts of eastern, central and southern Africa. In Zambia, theileriosis causes losses of up to 10,000 cattle annually.

          Methods

          Cattle blood samples were collected for genetic analysis of Theileria parva from Isoka and Petauke districts in Zambia. Microsatellite analysis was then performed on all Theileria parva positive samples for PCR using a panel of 9 microsatellite markers. Microsatellite data was analyzed using microsatellite toolkit, GenAlEx ver. 6, Fstat ver. 2.9.3.2, and LIAN computer softwares.

          Results

          The combined percentage of positive samples in both districts determined by PCR using the p104 gene primers was 54.9% (95% CI: 46.7 – 63.1%, 78/142), while in each district, it was 44.8% (95% CI: 34.8 – 54.8%) and 76.1% (95% CI = 63.9 – 88.4%) for Isoka and Petauke districts, respectively. We analyzed the population genetic structure of Theileria parva from a total of 61 samples (33 from Isoka and 28 from Petauke) using a panel of 9 microsatellite markers encompassing the 4 chromosomes of Theileria parva. Wright’s F index (F ST = 0.178) showed significant differentiation between the Isoka and Petauke populations. Linkage disequilibrium was observed when populations from both districts were treated as a single population. When analyzed separately, linkage disequilibrium was observed in Kanyelele and Kalembe areas in Isoka district, Isoka district overall and in Petauke district. Petauke district had a higher multiplicity of infection than Isoka district.

          Conclusion

          Population genetic analyses of Theileria parva from Isoka and Petauke districts showed a low level of genotype exchange between the districts, but a high level of genetic diversity within each district population, implying genetic and geographic sub-structuring between the districts. The sub-structuring observed, along with the lack of panmixia in the populations, could have been due to low transmission levels at the time of sampling. However, the Isoka population was less diverse than the Petauke population.

          Related collections

          Most cited references32

          • Record: found
          • Abstract: found
          • Article: not found

          Microsatellite markers reveal a spectrum of population structures in the malaria parasite Plasmodium falciparum.

          Multilocus genotyping of microbial pathogens has revealed a range of population structures, with some bacteria showing extensive recombination and others showing almost complete clonality. The population structure of the protozoan parasite Plasmodium falciparum has been harder to evaluate, since most studies have used a limited number of antigen-encoding loci that are known to be under strong selection. We describe length variation at 12 microsatellite loci in 465 infections collected from 9 locations worldwide. These data reveal dramatic differences in parasite population structure in different locations. Strong linkage disequilibrium (LD) was observed in six of nine populations. Significant LD occurred in all locations with prevalence <1% and in only two of five of the populations from regions with higher transmission intensities. Where present, LD results largely from the presence of identical multilocus genotypes within populations, suggesting high levels of self-fertilization in populations with low levels of transmission. We also observed dramatic variation in diversity and geographical differentiation in different regions. Mean heterozygosities in South American countries (0.3-0.4) were less than half those observed in African locations (0. 76-0.8), with intermediate heterozygosities in the Southeast Asia/Pacific samples (0.51-0.65). Furthermore, variation was distributed among locations in South America (F:(ST) = 0.364) and within locations in Africa (F:(ST) = 0.007). The intraspecific patterns of diversity and genetic differentiation observed in P. falciparum are strikingly similar to those seen in interspecific comparisons of plants and animals with differing levels of outcrossing, suggesting that similar processes may be involved. The differences observed may also reflect the recent colonization of non-African populations from an African source, and the relative influences of epidemiology and population history are difficult to disentangle. These data reveal a range of population structures within a single pathogen species and suggest intimate links between patterns of epidemiology and genetic structure in this organism.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            How clonal are bacteria?

            Data from multilocus enzyme electrophoresis of bacterial populations were analyzed using a statistical test designed to detect associations between genes at different loci. Some species (e.g., Salmonella) were found to be clonal at all levels of analysis. At the other extreme, Neisseria gonorrhoeae is panmictic, with random association between loci. Two intermediate types of population structure were also found. Neisseria meningitidis displays what we have called an "epidemic" structure. There is significant association between loci, but this arises only because of the recent, explosive, increase in particular electrophoretic types; when this effect is eliminated the population is found to be effectively panmictic. In contrast, linkage disequilibrium in a population of Rhizobium meliloti exists because the sample consisted of two genetically isolated divisions, often fixed for different alleles: within each division association between loci was almost random. The method of analysis is appropriate whenever there is doubt about the extent of genetic recombination between members of a population. To illustrate this we analyzed data on protozoan parasites and again found panmictic, epidemic, and clonal population structures.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Toxoplasma gondii comprises three clonal lineages: correlation of parasite genotype with human disease.

              The population genetic structure of Toxoplasma gondii was determined by multilocus restriction fragment length polymorphism analysis at 6 loci in 106 independent isolates from humans and animals. Phylogenetic and statistical analyses indicated a highly unusual population structure consisting of 3 widespread clonal lineages. Extensively mixed genotypes were only apparent in 4 strains, which indicated that, while not separate species, sexual recombination between the 3 lineages is exceedingly rare in natural populations. T. gondii is a major cause of subclinical human infection and an important opportunistic pathogen that causes severe disease in immunocompromised patients. While strains from all 3 lineages were isolated from humans, the majority of human toxoplasmosis cases were associated with strains of a type II genotype. The correlation of specific clonal lineages with human toxoplasmosis has important implications for development of vaccines, drug treatments, and diagnostic protocols.
                Bookmark

                Author and article information

                Journal
                Parasit Vectors
                Parasit Vectors
                Parasites & Vectors
                BioMed Central
                1756-3305
                2012
                12 November 2012
                : 5
                : 255
                Affiliations
                [1 ]Division of Molecular Pathobiology, Research Center for Zoonosis Control, Hokkaido University, N20, W10, Kita-ku, Sapporo, 001-0020, Japan
                [2 ]Department of Biomedical Sciences, School of Veterinary Medicine, University of Zambia, P.O Box 32379, Lusaka, 10101, Zambia
                [3 ]Department of Para-clinical Studies, School of Veterinary Medicine, University of Zambia, P.O Box 32379, Lusaka, 10101, Zambia
                [4 ]Department of Disease Control, School of Veterinary Medicine, University of Zambia, P.O Box 32379, Lusaka, 10101, Zambia
                [5 ]Division of Collaboration and Education, Research Center for Zoonosis Control, Hokkaido University, N20, W10, Kita-ku, Sapporo, 001-0020, Japan
                [6 ]National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Hokkaido, 080-8555, Japan
                [7 ]Division of Bioinformatics, Research Center for Zoonosis Control, Hokkaido University, N20, W10, Kita-ku, Sapporo, 001-0020, Japan
                [8 ]Global COE program, Research Center for Zoonosis Control, Hokkaido University, N20, W10, Kita-ku, Sapporo, 001-0020, Japan
                Article
                1756-3305-5-255
                10.1186/1756-3305-5-255
                3503576
                23146577
                dd523f18-48dc-4e5b-887c-b0960ee73421
                Copyright ©2012 Muleya et al.; licensee BioMed Central Ltd.

                This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

                History
                : 5 May 2012
                : 1 October 2012
                Categories
                Research

                Parasitology
                sub-structuring,zambia,theileria parva,genetic diversity
                Parasitology
                sub-structuring, zambia, theileria parva, genetic diversity

                Comments

                Comment on this article