Background: The World Health Organization recommends parasitological confirmation of all suspected malaria cases by microscopy or rapid diagnostic tests (RDTs) before treatment. These conventional tools are widely used for point-of-care diagnosis in spite of their poor sensitivity at low parasite density. Previous studies in Ghana have compared microscopy and RDT using standard 18S rRNA PCR as reference with varying outcomes. However, how these conventional tools compare with ultrasensitive varATS qPCR has not been studied. This study, therefore, sought to investigate the clinical performance of microscopy and RDT assuming highly sensitive varATS qPCR as gold standard. Methods: 1040 suspected malaria patients were recruited from two primary health care centers in the Ashanti Region of Ghana and tested for malaria by microscopy, RDT, and varATS qPCR. The sensitivity, specificity, and predictive values were assessed using varATS qPCR as gold standard. Results: Parasite prevalence was 17.5%, 24.5%, and 42.1% by microscopy, RDT, and varATS qPCR respectively. Using varATS qPCR as the standard, RDT was more sensitive (55.7% vs 39.3%), equally specific (98.2% vs 98.3%), and reported higher positive (95.7% vs 94.5%) and negative predictive values (75.3% vs 69.0%) than microscopy. Consequently, RDT recorded better diagnostic agreement (kappa = 0.571) with varATS qPCR than microscopy (kappa = 0.409) for clinical detection of malaria. Conclusions: RDT outperformed microscopy for the diagnosis of Plasmodium falciparum malaria in the study. However, both tests missed over 40% of infections that were detected by varATS qPCR. Novel tools are needed to ensure prompt diagnosis of all clinical malaria cases.

Malaria represents a major public health problem in Africa. In the East African highlands, the high-altitude areas were previously considered too cold to support vector population and parasite transmission, rendering the region particularly prone to epidemic malaria due to the lack of protective immunity of the population. Since the 1980’s, frequent malaria epidemics have been reported and these successive outbreaks may have generated some immunity against Plasmodium falciparum amongst the highland residents. Serological studies reveal indirect evidence of human exposure to the parasite, and can reliably assess prevalence of exposure and transmission intensity in an endemic area. However, the vast majority of serological studies of malaria have been, hereto, limited to a small number of the parasite’s antigens. We surveyed and compared the antibody response profiles of age-stratified sera from residents of two endemic areas in the western Kenyan highlands with differing malaria transmission intensities, during two distinct seasons, against 854 polypeptides of P. falciparum using high-throughput proteomic microarray technology. We identified 107 proteins as serum antibody targets, which were then characterized for their gene ontology biological process and cellular component of the parasite, and showed significant enrichment for categories related to immune evasion, pathogenesis and expression on the host’s cell and parasite’s surface. Additionally, we calculated age-fitted annual seroconversion rates for the immunogenic proteins, and contrasted the age-dependent antibody acquisition for those antigens between the two sampling sites. We observed highly immunogenic antigens that produce stable antibody responses from early age in both sites, as well as less immunogenic proteins that require repeated exposure for stable responses to develop and produce different seroconversion rates between sites. We propose that a combination of highly and less immunogenic proteins could be used in serological surveys to detect differences in malaria transmission levels, distinguishing sites of unstable and stable transmission.

Most rapid diagnostic tests for Plasmodium falciparum malaria target the Histidine-Rich Proteins 2 and 3 (HRP2 and HRP3). Deletions of the hrp2 and hrp3 genes result in false-negative tests and are a threat for malaria control. A novel assay for molecular surveillance of hrp2/hrp3 deletions was developed based on droplet digital PCR (ddPCR). The assay quantifies hrp2, hrp3, and a control gene with very high accuracy. The theoretical limit of detection was 0.33 parasites/µl. The deletion was reliably detected in mixed infections with wild-type and hrp2-deleted parasites at a density of >100 parasites/reaction. For a side-by-side comparison with the conventional nested PCR (nPCR) assay, 248 samples were screened in triplicate by ddPCR and nPCR. No deletions were observed by ddPCR, while by nPCR hrp2 deletion was observed in 8% of samples. The ddPCR assay was applied to screen 830 samples from Kenya, Zanzibar/Tanzania, Ghana, Ethiopia, Brazil, and Ecuador. Pronounced differences in the prevalence of deletions were observed among sites, with more hrp3 than hrp2 deletions. In conclusion, the novel ddPCR assay minimizes the risk of false-negative results (i.e., hrp2 deletion observed when the sample is wild type), increases sensitivity, and greatly reduces the number of reactions that need to be run.

The existing metrics of malaria transmission are limited in sensitivity under low transmission intensity. Robust surveillance systems are needed as interventions to monitor reduced transmission and prevention of rapid reintroduction. Serological tools based on antibody responses to parasite and vector antigens are potential tools for transmission measurements. The current study sought to evaluate antibody responses to Anopheles gambiae salivary gland peptide (gSG6- P1), as a biomarker of human exposure to Anopheles bites, in different transmission settings and seasons. The comparison between anti-MSP-119 IgG immune responders and non-responders allowed exploring the robustness of the gSG6-P1 peptide as a surveillance tool in an area of decreasing malaria transmission.

Malaria and HIV/AIDS are the two most common infections in sub-Sahara Africa. There are hypotheses and study reports on the possible association between these two infections, hence the prevalence and outcome of their co-infection in an endemic population will be important in defining healthcare strategies. A cross sectional study was carried out at the Holy Family Hospital in Techiman, Ghana, between November 2011 and January 2012, to determine the prevalence of malaria among HIV sero-positive patients and its impact on hemoglobin levels. A total of 400 HIV sero-positive participants (292 females and 108 males) aged between 1 and 73 years were randomly sampled for the study. A questionnaire was administered and 2 ml of venous blood samples were drawn for malaria parasites detection, CD4 count and haemoglobin level estimations. Malaria parasites were detected in 47 (11.75%) of the participants. There was no statistically significant difference between the malaria prevalence rate of females (12.1%) and males (10.2%) P = 0.6047. An overall anaemia prevalence of 67% was observed. Among participants with malaria the anaemia prevalence was 93.6%. The CD4 cell count of all the participants ranged between 3 and 1604 cells/μl with a mean of 386.2 (±274.3) cells/μl. Participants with malaria had CD4 cell count ranged 3 and 512 Cells/μl with the mean being 186.33 (±133.49) Cells/μl. Out of 377 participants (all above 15 years) interviewed on knowledge of malaria transmission and prevention, 87.0% had knowledge on transmission but only 8.5% use in bed nets. It was revealed that almost all the patients with malaria infection were anemic.

Ebola virus is a severe, frequently fatal illness, with a case fatality rate up to 90%. The outbreak of the disease has been acknowledged by World Health Organization as Public Health Emergency of International Concern. The threat of Ebola in West Africa is still a major setback to the socioeconomic development. Optimal control theory is applied to a system of ordinary differential equations which is modeling Ebola infection through three different routes including contact between humans and a dead body. In an attempt to reduce infection in susceptible population, a preventive control is put in the form of education and campaign and two treatment controls are applied to infected and late-stage infected (super) human population. The Pontryagins maximum principle is employed to characterize optimality control, which is then solved numerically. It is observed that time optimal control is existed in the model. The activation of each control showed a positive reduction of infection. The overall effect of activation of all the controls simultaneously reduced the effort required for the reduction of the infection quickly. The obtained results present a good framework for planning and designing cost-effective strategies for good interventions in dealing with Ebola disease. It is established that in order to reduce Ebola threat all the three controls must be taken into consideration concurrently.