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Pregnant women have increased susceptibility to malaria infection. In these women, malaria parasites are frequently found sequestered in the placental intervillous spaces, a condition referred to as placental malaria (PM). Placental malaria threatens the health of the mother and the child's life by causing still births and reduction in gestational age. An estimated 24 million pregnant women in Sub-Saharan Africa are at risk. Mechanisms responsible for increased susceptibility in pregnant women are not fully understood. Pregnancy malaria studies have been limited by the lack of a suitable animal model. This research aimed to develop a baboon (Papio anubis) model for studying PM. The pregnancies of three adult female baboons were synchronized and their gestational levels confirmed by ultrasonography. On the 150th day of gestation the pregnant baboons were infected with Plasmodium knowlesi H strain parasites together with four nulligravid control baboons. Parasitaemia was monitored from two days post inoculation until the 159th day of gestation when caesarean section was done on one baboon in order to obtain the placenta. Two baboons aborted their conceptus. Smears prepared from placental blood demonstrated the presence of Plasmodium knowlesi parasites in all the three sampled placentas. These new findings show that P. knowlesi sequesters in the baboon placenta. In addition, this study has characterized haemoglobin, eosinophil, Immunoglobulin G and Immunoglobulin M profiles in this model. Thus a non human primate (baboon) model for studying PM has been established. The established baboon - P. knowlesi model for studying human placental/pregnancy malaria now offers an opportunity for circumventing the obstacles experienced during human studies like having inadequate tissue for analysis, inaccurate estimation of gestational age, moral, ethical and financial limitations., Comment: Five pages, four figures: This reserch was supported by the research capability strengthening World Health Organisation (WHO Grant Number: A 50075) for malaria research in Africa under the Multilateral Initiative on Malaria / Special Programme for Research and Training in Tropical Diseases (WHO-MIM/TDR). The Institute of Primate Research in Nairobi (Kenya) provided the research facilities

Approximately 24 million pregnant women in Sub-Saharan Africa are at risk of suffering from pregnancy malaria complications. Mechanisms responsible for increased susceptibility to malaria in pregnant women are not fully understood. Baboons are susceptible to Plasmodium knowlesi and their reproductive physiology and host pathogen interactions are similar to those in humans, making them attractive for development as a model for studying mechanisms underlying pregnancy malaria. This study exploited the susceptibility of baboons to Plasmodium knowlesi infection to characterize cytokine and peripheral blood mononuclear cell recall proliferation responses underlying the pathogenesis of pregnancy malaria in baboons infected with Plasmodium knowlesi. The pregnancies of three time mated adult female baboons and their gestational levels were confirmed by ultrasonography. On the 150th day of gestation, the pregnant baboons together with four non pregnant controls were infected with Plasmodium knowlesi H strain parasites. Collection of peripheral sera, and mononuclear cells was then done on a weekly basis. Sera cytokine concentrations were measured by Enzyme Linked Immunosorbent Assay (ELISA) using respective enzyme conjugated antibodies. Peripheral blood mononuclear cell recall proliferation assays were also done on a weekly basis. Results indicate that pregnancy malaria in this model is associated with suppression of interferon gamma and interleukin 6 (IL-6) responses. Tumour necrosis factor alpha responses were upregulated while IL-4, IL-12 and recall proliferation responses were not different from controls. These data to a great extent are consistent with some findings from human studies, showing the feasibility of this model for studying mechanisms underlying pregnancy malaria., Comment: Five pages, six figures;This study was funded by the research capability strengthening WHO grant (Grant Number: A 50075) for malaria research in Africa under the Multilateral Initiative on Malaria/Special Programme for Research and Training in Tropical Diseases (WHO-MIM/TDR).The Institute of Primate Research (IPR) in Nairobi (Kenya) provided the baboons and laboratory facilities for the study

Malaria disease is a major global health and economic development threat. It results in approximately 2.7 million deaths annually. There is currently no vaccine that has been licensed for use against malaria. Studies in animal models, especially non-human primates can lead to the revelation of possible immunological mechanisms that can lead to protection or predisposition of the host to malaria. Plasmodium knowlesi, a simian and human malaria parasite, is an attractive experimental parasite for malaria research since it can infect olive baboons (Papio anubis), non-human primates that have similar host-pathogen interactions to humans. This study was carried out to determine host immunological profiles provoked in olive baboons during the course of an infection with Plasmodium knowlesi. A total of eight adult baboons were intravenously inoculated with overnight cultured blood stage P. knowlesi H strain parasites. Five of these baboons became acutely infected while the other three became chronically infected. The immunological basis of this dual outcome of the infection was determined by measuring circulating cytokine (T helper 1 and T helper 2) and antibody (immunoglobulin G and immunoglobulin M) responses elicited in the infected baboons on a weekly basis by Enzyme Linked Immunosorbent Assay (ELISA) for up to six weeks post infection. Generated data for the first time indicated that acute P. knowlesi malaria is accompanied by increased concentrations of interferon gamma (IFN gamma), tumour necrosis factor alpha (TNF alpha) and IL 6 and reduced levels of circulating interleukin 10 (IL 10), IL 4, IL 12, immunoglobulin G (IgG) and IgM in the baboon host. These results are largely agreeable with data from human studies, thereby increasing the relevance of the olive baboon - P. knowlesi experimental infection system for future malaria studies., Comment: 6 Pages, 8 Figures; This study was funded by the research capability strengthening World Health Organisation (WHO) grant (Grant Number: A 50075) for malaria research in Africa under the Multilateral Initiative on Malaria/Special Programme for Research and Training in Tropical Diseases (WHO-MIM/TDR). Blue highlighting on previous abstract removed, title font increased