Genetic diversity, breed composition and admixture of Kenyan domestic pigs

<div><p>The genetic diversity of African pigs, whether domestic or wild has not been widely studied and there is very limited published information available. Available data suggests that African domestic pigs originate from different domestication centers as opposed to international commercial breeds. We evaluated two domestic pig populations in Western Kenya, in order to characterize the genetic diversity, breed composition and admixture of the pigs in an area known to be endemic for African swine fever (ASF). One of the reasons for characterizing these specific populations is the fact that a proportion of indigenous pigs have tested ASF virus (ASFv) positive but do not present with clinical symptoms of disease indicating some form of tolerance to infection. Pigs were genotyped using either the porcine SNP60 or SNP80 chip. Village pigs were sourced from Busia and Homabay counties in Kenya. Because bush pigs (<i>Potamochoerus larvatus</i>) and warthogs (<i>Phacochoerus spp</i>.) are known to be tolerant to ASFv infection (exhibiting no clinical symptoms despite infection), they were included in the study to assess whether domestic pigs have similar genomic signatures. Additionally, samples representing European wild boar and international commercial breeds were included as references, given their potential contribution to the genetic make-up of the target domestic populations. The data indicate that village pigs in Busia are a non-homogenous admixed population with significant introgression of genes from international commercial breeds. Pigs from Homabay by contrast, represent a homogenous population with a “local indigenous’ composition that is distinct from the international breeds, and clusters more closely with the European wild boar than African wild pigs. Interestingly, village pigs from Busia that tested negative by PCR for ASFv genotype IX, had significantly higher local ancestry (>54%) compared to those testing positive, which contained more commercial breed gene introgression. This may have implication for breed selection and utilization in ASF endemic areas. A genome wide scan detected several regions under preferential selection with signatures for pigs from Busia and Homabay being very distinct. Additionally, there was no similarity in specific genes under selection between the wild pigs and domestic pigs despite having some broad areas under similar selection signatures. These results provide a basis to explore possible genetic determinants underlying tolerance to infection by ASFv genotypes and suggests multiple pathways for genetically mediated ASFv tolerance given the diversity of selection signatures observed among the populations studied.</p></div

FUNCTIONAL AND IMMUNOLOGICAL CHARACTERIZATION OF CLAMP AND RAP-1 PROTEINS IN THEILERIA EQUI

Theileria equi (T. equi) is one of the causative agents of equine piroplasmosis, a severe tick-transmitted disease that affects most equid species. Control of the parasite is impeded by the lack of an effective vaccine and the fact that it can be transmitted by multiple tick vectors. T. equi is classified within the phylum Apicomplexa due to the presence of secretory organelles (micronemes, rhoptries and dense granules) on the apical end of the parasite that are essential for invasion and establishment of apicomplexans within host cells. Unlike most apicomplexan species, the roles of these organelles, and their contents in host cell invasion remain unexplored in T. equi. In chapter one, we evaluate the role of T. equi micronemes by assessing the role of the claudin like apicomplexan microneme protein (CLAMP) in erythrocyte invasion and identify equine erythrocyte components that interact with the protein during cell entry. We also assess expression of CLAMP in the merozoite and intra-erythrocytic developmental stages of T. equi and evaluate its immunogenicity as a potential vaccine candidate. The results show that the protein is expressed in both developmental stages and elicits significant antibody responses in horses during T. equi infection, indicating that it is a viable candidate for vaccine development. The results also show that CLAMP is involved in invasion of equine erythrocytes and the protein interacts with key components of the equine erythrocyte cytoskeleton during cell entry. In chapter two, we evaluate the role of T. equi rhoptries in invasion. In this regard, we assess the expression of the rhoptry associated protein-1a and -1b (RAP-1a and RAP-1b) in the merozoite and intra-erythrocytic developmental stages of T. equi and evaluate their immunogenicity and roles in invasion. Our findings show that both proteins are expressed in both developmental stages and while RAP-1a is highly immunogenic and involved in erythrocyte entry, the N- and C-termini of RAP-1b are not required for cell entry and are not immunogenic. In conclusion, our findings show that like most apicomplexan species, the T. equi secretory organelles are involved in invasion and their contents can be targeted for vaccine development

Who’s Governing Community Forests? Gendered Participation in Liberian Forest Management

Published on the website for the World Resources Institute, a global research organization. Across sub-Saharan Africa, women play an important role in managing the forests that support their lives, livelihoods and households. Yet they are often excluded from decision-making processes affecting these natural resources. As many African countries take steps to decentralize natural resource management and strengthen local forest governance mechanisms, it is critical to understand the barriers that women face when they try to engage in forest management. Doing so can help ensure that decisions made at both national and community levels protect women’s access to forest resources as well as benefit from their wisdom on sustainable management. This paper examines how power relations, authority and competing interests converge to shape both resource access as well as individual community members’ ability to participate in forest management. It identifies patterns of engagement in forest governance, explains these trends and highlights pathways through which women’s participation in managing these ecosystems may be improved. Field research, conducted in collaboration with Clark University and the Foundation for Community Initiatives (FCI) in Liberia, finds that women’s livelihoods and the sustainability of forest resources would greatly benefit from women’s participation in local decision-making processes. Women, for example, often possess unique knowledge and skills that can help improve forest management, because they tend to use different forest resources than men. However, significant regulatory and social changes are needed to achieve this goal. This paper finds that a deeper understanding of local power relations and social dynamics must underpin efforts to foster gender and social equity. Such an analysis can also help decision-makers avoid risks to already vulnerable people and the forest resources on which they depend

A U.S. Isolate of <i>Theileria orientalis</i> Ikeda Is Not Transstadially Transmitted to Cattle by <i>Rhipicephalus microplus</i>

Theileria orientalis Ikeda has caused an epidemic of bovine anemia and abortion across several U.S. states. This apicomplexan hemoparasite is transmitted by Haemaphysalis longicornis ticks; however, it is unknown if other North American ticks are competent vectors. Since the disease movement is largely determined by the host tick range(s), the prediction of the T. orientalis spread among U.S. cattle populations requires determination of additional competent tick vectors. Although Rhipicephalus microplus has mostly been eradicated from the U.S., outbreaks in populations occur frequently, and the U.S. remains at risk for reintroduction. Since R. microplus is a vector of Theileria equi and T. orientalis DNA has been detected in R. microplus, the goal of this study was to determine whether R. microplus is a competent vector of T. orientalis. Larval R. microplus were applied to a splenectomized, T. orientalis Ikeda-infected calf for parasite acquisition, removed as molted adults, and applied to two T. orientalis naïve, splenectomized calves for transmission. After 60 days, the naïve calves remained negative for T. orientalis by PCR and cytology. Additionally, T. orientalis was not detected in the salivary glands or larval progeny of acquisition-fed adults. These data suggest that R. microplus is not a competent vector of the U.S. T. orientalis Ikeda isolate

<i>Dermacentor variabilis</i> Does Not Transstadially Transmit the U.S. Isolate of <i>Theileria orientalis</i> Ikeda: A Controlled Acquisition and Transmission Study

Theileria orientalis Ikeda, an emerging U.S. bovine hemoparasite, causes anemia, abortion, ill-thrift, and occasionally death. While Haemaphysalis longicornis is the primary vector, it is possible that other U.S. ticks are capable of parasite transmission and may contribute to disease spread. Dermacentor variabilis is highly prevalent in the U.S., exhibits a similar geographical distribution to T. orientalis, and is a competent vector of the related parasite, Theileria equi. Herein, we conducted controlled acquisition and transmission studies using splenectomized calves to assess whether D. variabilis can transstadially transmit T. orientalis. D. variabilis nymphs were applied to an infected, splenectomized calf for parasite acquisition and subsequently incubated to molt into adults. Freshly molted adults were applied to two splenectomized T. orientalis-naïve calves to investigate parasite transmission. Calves were monitored for 59 days, and no evidence of parasite transmission was detected using PCR for the T. orientalis Ikeda major piroplasm surface protein gene, blood smear cytology, complete blood counts, or physical examination. Salivary glands from a subset of D. variabilis adults were assessed for T. orientalis using PCR, and the parasite was not detected. These findings support the conclusion that D. variabilis is not capable of transstadial transmission of the U.S. T. orientalis Ikeda isolate