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

Muleya Walter, Namangala Boniface, Simuunza Martin, Nakao Ryo, Inoue Noboru, Kimura Takashi, Ito Kimihito, Sugimoto Chihiro, Sawa, Sawa Hirofumi

Description

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.

Sujets

• Theileria parva
• Genetic diversity
• Zambia

Informations

• Publié par: biomed
• Publié le: 01 janvier 2012
• Nombre de lectures: 10
• Langue: English

Extrait

Muleyaet al. Parasites & Vectors2012,5:255 http://www.parasitesandvectors.com/content/5/1/255

R E S E A R C H

Open Access

Population genetic analysis and substructuring ofTheileria parvain the northern and eastern parts of Zambia 1,2†3†4†5†6†1† Walter Muleya , Boniface Namangala , Martin Simuunza , Ryo Nakao , Noboru Inoue , Takashi Kimura , 7,8†5,8†1,8* Kimihito Ito , Chihiro Sugimoto and Hirofumi Sawa

Abstract Background:Theileriosis, caused byTheileria 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 ofTheileria parvafrom Isoka and Petauke districts in Zambia. Microsatellite analysis was then performed on allTheileria parvapositive 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 ofTheileria parvafrom a total of 61 samples (33 from Isoka and 28 from Petauke) using a panel of 9 microsatellite markers encompassing the 4 chromosomes ofTheileria 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 ofTheileria parvafrom 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. Keywords:Theileria parva, Genetic diversity, Substructuring, Zambia

* Correspondence: h[e-mail] † Equal contributors 1 Division of Molecular Pathobiology, 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 Full list of author information is available at the end of the article

© 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.