Critical Steps of Plasmodium falciparum Ookinete Maturation

The egress and fertilization of Plasmodium gametes and development of a motile ookinete are the first crucial steps that mediate the successful transmission of the malaria parasites from humans to the Anopheles vector. However, limited information exists about the cell biology and regulation of this process. Technical impediments in the establishment of in vitro conditions for ookinete maturation in Plasmodium falciparum and other human malaria parasites further constrain a detailed characterization of ookinete maturation. Here, using fluorescence microscopy and immunolabeling, we compared P. falciparum ookinete maturation in Anopheles coluzzii mosquitoes in vivo and in cell culture in vitro. Our results identified two critical steps in ookinete maturation that are regulated by distinct mosquito factors, thereby highlighting the role of the mosquito environment in the transmission efficiency of malaria parasites

Malaria Diagnosis and the Plasmodium Life Cycle: the BFO Perspective

Definitive diagnosis of malaria requires the demonstration through laboratory tests of the presence within the patient of malaria parasites or their components. Since malaria parasites can be present even in the absence of malaria, and since symptoms of malaria can be manifested even in the absence of malaria parasites, malaria diagnosis raises important issues for the adequate understanding of disease, etiology and diagnosis. One approach to the resolution of these issues adopts a realist view, according to which the needed clarifications will be derived from a careful representation of the entities on the side of the patient which form the ultimate truthmakers for clinical statements. We address a challenge to this realist approach relating to the diagnosis of malaria, and show how this challenge can be resolved by appeal to Basic Formal Ontology (BFO) and to the Ontology for General Medical Science (OGMS) constructed in its terms

Prevalence of malaria parasites among blood donors in Kaduna, Nigeria

Background: Transmission of malaria parasites through blood transfusion is a well-known serious risk. Screening of blood donors for malaria as recommended by WHO is currently not included in the protocols of many Nigerian blood banks. Presence of asymptomatic Plasmodium species carriers (APCs) in some northern parts of the state has already been demonstrated using rapid diagnostic tests (RDTs) and microscopic examination of Giemsa stained blood films. This research was undertaken to determine the prevalence of malaria parasites among blood donors in Kaduna state, Nigeria.Methods: A cross sectional study was conducted among the blood donors in the three selected Hospitals of Kaduna state. A well-structured questionnaire was used to collect the data regarding demographic profile. Written informed consent was obtained and questionnaire was completed by respondents selected through simple random sampling. 360 blood donors were tested for malaria parasites through microscopic examination of Giemsa stained thick and thin blood films. The data were analysed using Statistical analysis system (SAS) and statistical software for social sciences (SPSS) version 20.Results: A total of 27 (7.5%) of the blood donors had malaria parasites in their blood. Plasmodium falciparum was the only malaria parasite species encountered. There were no mixed infections and no other blood parasites were observed. The prevalence of malaria parasites in the blood donors was significantly associated with occupation (c2=24.0845, df=6, p= 0.0005) and blood group (c2=10.589, df=4, p= O.032). The infected subjects had parasites densities of between 88-250 parasites/µl with a mean parasite density of 126 parasites/µl of blood.Conclusions: The prevalence of malaria parasites among blood donors was 7.5% Blood donors should be routinely screened for malaria parasites and the blood marked negative or positive as the case may be. Recipients of malaria parasites positive blood should be given prophylactic treatment to prevent transfusion related malaria (TRM).

Primate malarias: Diversity, distribution and insights for zoonotic Plasmodium

Protozoans within the genus Plasmodium are well-known as the causative agents of malaria in humans. Numerous Plasmodium species parasites also infect a wide range of non-human primate hosts in tropical and sub-tropical regions worldwide. Studying this diversity can provide critical insight into our understanding of human malarias, as several human malaria species are a result of host switches from non-human primates. Current spillover of a monkey malaria, Plasmodium knowlesi, in Southeast Asia highlights the permeability of species barriers in Plasmodium. Also recently, surveys of apes in Africa uncovered a previously undescribed diversity of Plasmodium in chimpanzees and gorillas. Therefore, we carried out a meta-analysis to quantify the global distribution, host range, and diversity of known non-human primate malaria species. We used published records of Plasmodium parasites found in non-human primates to estimate the total diversity of non-human primate malarias globally. We estimate that at least three undescribed primate malaria species exist in sampled primates, and many more likely exist in unstudied species. The diversity of malaria parasites is especially uncertain in regions of low sampling such as Madagascar, and taxonomic groups such as African Old World Monkeys and gibbons. Presence–absence data of malaria across primates enables us to highlight the close association of forested regions and non-human primate malarias. This distribution potentially reflects a long coevolution of primates, forest-adapted mosquitoes, and malaria parasites. The diversity and distribution of primate malaria are an essential prerequisite to understanding the mechanisms and circumstances that allow Plasmodium to jump species barriers, both in the evolution of malaria parasites and current cases of spillover into humans

Prevalence of Malaria Parasites and Associated Factors among Blood Donors Attending General Hospital Minna, Niger State, Nigeria

The prevalence of malaria parasites among the blood donors attending General Hospital Minna was studied over a period of four (4)  months. Both thick and thin films were made on a clean grease-free glass slide. 10% Giemsa was used to determine the presence of malaria parasites in the donors’ blood. A total number of 200 male blood donors’ samples were collected out of which 47 were malaria parasite positive, while 153 were malaria parasite negative (control), representing a prevalence rate of 23.5%. The age group 18-24 years had the highest prevalence of malaria parasite (33.3%). Donors with blood group AB had the highest prevalence of malaria parasite (42.1 %). The various factors except age, blood group and occupation in the questionnaire were significant. The prevalence of malaria parasites within the sampled hospital was high. Therefore, it is necessary that more education, enlightenment, prevention and treatment should be given to people that are positive to malaria parasites in order to eradicate malaria parasites or bring it to a minimal level

Distribution and prevalence of malaria parasites among long-tailed macaques (Macaca fascicularis) in regional populations across Southeast Asia.

BackgroundPlasmodium knowlesi and Plasmodium cynomolgi are two malaria parasites naturally transmissible between humans and wild macaque through mosquito vectors, while Plasmodium inui can be experimentally transmitted from macaques to humans. One of their major natural hosts, the long-tailed macaque (Macaca fascicularis), is host to two other species of Plasmodium (Plasmodium fieldi and Plasmodium coatneyi) and is widely distributed in Southeast Asia. This study aims to determine the distribution of wild macaques infected with malarial parasites by examining samples derived from seven populations in five countries across Southeast Asia.MethodsPlasmodium knowlesi, P. cynomolgi, P. coatneyi, P. inui and P. fieldi, were detected using nested PCR assays in DNA samples from 276 wild-caught long-tailed macaques. These samples had been derived from macaques captured at seven locations, two each in the Philippines (n = 68) and Indonesia (n = 70), and one each in Cambodia (n = 54), Singapore (n = 40) and Laos (n = 44). The results were compared with previous studies of malaria parasites in long-tailed macaques from other locations in Southeast Asia. Fisher exact test and Chi square test were used to examine the geographic bias of the distribution of Plasmodium species in the macaque populations.ResultsOut of 276 samples tested, 177 were Plasmodium-positive, with P. cynomolgi being the most common and widely distributed among all long-tailed macaque populations (53.3 %) and occurring in all populations examined, followed by P. coatneyi (20.4 %), P. inui (12.3 %), P. fieldi (3.4 %) and P. knowlesi (0.4 %). One P. knowlesi infection was detected in a macaque from Laos, representing the first documented case of P. knowlesi in wildlife in Laos. Chi square test showed three of the five parasites (P. knowlesi, P. coatneyi, P. cynomolgi) with significant bias in prevalence towards macaques from Malaysian Borneo, Cambodia, and Southern Sumatra, respectively.ConclusionsThe prevalence of malaria parasites, including those that are transmissible to humans, varied among all sampled regional populations of long-tailed macaques in Southeast Asia. The new discovery of P. knowlesi infection in Laos, and the high prevalence of P. cynomolgi infections in wild macaques in general, indicate the strong need of public advocacy in related countries

An evolutionary perspective on the kinome of malaria parasites

Malaria parasites belong to an ancient lineage that diverged very early from the main branch of eukaryotes. The approximately 90-member plasmodial kinome includes a majority of eukaryotic protein kinases that clearly cluster within the AGC, CMGC, TKL, CaMK and CK1 groups found in yeast, plants and mammals, testifying to the ancient ancestry of these families. However, several hundred millions years of independent evolution, and the specific pressures brought about by first a photosynthetic and then a parasitic lifestyle, led to the emergence of unique features in the plasmodial kinome. These include taxon-restricted kinase families, and unique peculiarities of individual enzymes even when they have homologues in other eukaryotes. Here, we merge essential aspects of all three malaria-related communications that were presented at the Evolution of Protein Phosphorylation meeting, and propose an integrated discussion of the specific features of the parasite's kinome and phosphoproteome

Malaria parasite detection increases during pregnancy in wild chimpanzees

Background: The diversity of malaria parasites (Plasmodium sp.) infecting chimpanzees (Pan troglodytes) and their close relatedness with those infecting humans is well documented. However, their biology is still largely unexplored and there is a need for baseline epidemiological data. Here, the effect of pregnancy, a well-known risk factor for malaria in humans, on the susceptibility of female chimpanzees to malaria infection was investigated. Methods: A series of 384 faecal samples collected during 40 pregnancies and 36 post-pregnancies from three habituated groups of wild chimpanzees in the Tai National Park, Cote d'Ivoire, were tested. Samples were tested for malaria parasites by polymerase chain reaction (PCR) and sequencing. Data were analysed using a generalized linear mixed model. Results: Probability of malaria parasite detection significantly increased towards the end of pregnancy and decreased with the age of the mother. Conclusions: This study provides evidence that susceptibility to malaria parasite infection increases during pregnancy, and, as shown before, in younger individuals, which points towards similar dynamics of malaria parasite infection in human and chimpanzee populations and raises questions about the effects of such infections on pregnancy outcome and offspring morbidity/mortality

Evaluation of CD4+ T Cells in HIV Patients Presenting with Malaria at the University of Ilorin Teaching Hospital Nigeria

CD4 count is an important immunological marker of disease progression in HIV seropositive patients. This study was carried out to determine the effect of malaria or fever of unknown origin on the population of CD4+ T lymphocytes of HIV seropositive patients attending the highly active antiretroviral therapy (HAART) clinic of the University of Ilorin Teaching Hospital, Ilorin, Nigeria. 36 subjects were selected for this study. Ongoing history of fever was used as a case definition for malaria and malaria was confirmed from microscopic examination of thick and thin film of blood sample obtained from the patients during presentation with fever. The CD4 count was evaluated during presentation of fever and post-fever using flow cytometry. There was significant decrease in CD4 count of the patients. However, upon classifying the patients into 2 groups - those that returned to the clinic after a week and those that returned after a month - a significant increase in CD4 count was noticed in the group that returned after a week, while a significant decrease was noticed in the group that returned after a month (at p value of 95%). Further classification of the patients based on presence of malaria parasite, and body temperature resulted in varying effects on CD4 count post-fever (in the general group, 27 were positive for malaria parasites. Of these 27, there was an increase in CD4 count in 9 (33.3%). However in the group that returned after a week, all 6 (100%) that were positive for malaria parasites showed increase in CD4 count. Five (26.3%) of the 19 patients that had body temperature within the range of 35.5-37.4^o^C showed an increase in CD4 count, while 7 (41.2%) the 17 patients that had body temperature of 37.5^o^C and above showed an increase in CD4 count. The results led to the conclusion that while some components of the immune response to malaria could strengthen the immune system of HIV seropositive patients by increasing their CD4 count, other components will suppress their immunity by decreasing their CD4 count, accelerating the progression to AIDS