Comparative performance evaluation of blood film microscopy for the diagnosis of bovine trypanosomosis by some laboratories in North-central Nigeria.

Background: Due to its affordability in disease-affected communities and suitability for field application, microscopy has historically been considered the gold standard for field diagnosis of trypanosomosis in rural settings. Aim: This works aims to compare the performance of microscopists on bovine trypanosome microscopy by organizing the first comparative assessment on a correct reading of slides by laboratory professionals using the read slide results and a structured interviewer-administered questionnaire in North-central Nigeria. Methods: Ten participants were addressed, as they were sent a panel of two slides (Slide 1: No Trypanosome present; Slide 2: Trypanosome present) and a questionnaire. Results: All participants greater than 41 years old reported correctly the presence and absence of parasites on slides. Only 3/8 of microscopists from routine diagnostic laboratories reported correctly the presence of the parasite. Conclusion: Our study confirmed errors in reading slides. Therefore, training of microscopists besides a nationwide quality assessment is recommended.

Quantitative Synthesis of Factors Associated with COVID-19 Vaccine Acceptance and Vaccine Hesitancy in 185 Countries.

Mass vaccination against COVID-19 is the best method to ensure herd immunity in order to curb the effect of the pandemic on the global economy. It is therefore important to assess the determinants of COVID-19 vaccine acceptance and hesitancy on a global scale. Factors were recorded from cross-sectional studies analyzed with t-Test, ANOVA, correlation, and meta-regression analyses and synthesized to identify global trends in order to inform policy. We registered the protocol (ID: CRD42022350418) and used standard Cochrane methods and PRISMA guidelines to collect and synthesize cross-sectional articles published between January 2020 and August 2023. A total of 67 articles with 576 studies from 185 countries involving 3081,766 participants were included in this synthesis. Global COVID-19 vaccine acceptance was 65.27% (95% CI; 62.72-67.84%), while global vaccine hesitancy stood at 32.1% (95% CI; 29.05-35.17%). One-Way ANOVA showed that there was no significant difference in the percentage Gross Domestic Product spent on vaccine procurement across the World Bank income levels (p < 0.187). There was a significant difference of vaccine acceptance (p < 0.001) and vaccine hesitancy (p < 0.005) across the different World Bank Income levels. World Bank income level had a strong influence on COVID-19 vaccine acceptance (p < 0.0004) and hesitancy (p < 0.003) but percentage Gross Domestic Product spent on vaccine procurement did not. There was no correlation between percentage Gross Domestic Product spent on vaccine procurement and COVID-19 vaccine acceptance (r = -0.11, p < 0.164) or vaccine hesitancy (r = -0.09, p < 0.234). Meta-regression analysis showed that living in an urban setting (OR = 4.83, 95% CI; 0.67-212.8), rural setting (OR = 2.53, 95% CI; 0.29-119.33), older (OR = 1.98, 95% CI; 0.99-4.07), higher education (OR = 1.76, 95% CI; 0.85-3.81), and being a low income earner (OR = 2.85, 95% CI; 0.45-30.63) increased the odds of high COVID-19 vaccine acceptance. Factors that increased the odds of high COVID-19 vaccine hesitancy were no influenza vaccine (OR = 33.06, 95% CI; 5.03-1395.01), mistrust for vaccines (OR = 3.91, 95% CI; 1.92-8.24), complacency (OR = 2.86, 95% CI; 1.02-8.83), pregnancy (OR = 2.3, 95% CI; 0.12-141.76), taking traditional herbs (OR = 2.15, 95% CI; 0.52-10.42), being female (OR = 1.53, 95% CI; 0.78-3.01), and safety concerns (OR = 1.29, 95% CI; 0.67-2.51). We proposed a number of recommendations to increase vaccine acceptance and ensure global herd immunity against COVID-19.

Factors Driving COVID-19 Vaccine Hesitancy in Cameroon and Their Implications for Africa: A Comparison of Two Cross-Sectional Studies Conducted 19 Months Apart in 2020 and 2022.

Many efficacious COVID-19 vaccines have been approved for general use but their ability to control the disease is being undermined by slow uptake. Resources are needed to persuade people to obtain a COVID-19 vaccine. Here we compare this present study and a previous one to assess the impact of the Cameroon government's policy and efforts to reduce COVID-19 vaccine hesitancy after one year of implementation. After obtaining ethical clearance and informed consent, 6732 participants completed a questionnaire about COVID-19 vaccine hesitancy and acceptance. It was observed that the government's policies and efforts reduced COVID-19 vaccine hesitancy significantly, but this was not enough to ensure the herd immunity necessary to control the disease. The risk factors associated with vaccine hesitancy were the consumption of traditional herbal remedies; living in an urban setting; being female, jobless or a student; working in the education sector; being a politician/policy maker/administrator, engineer or technician; medium income; no education/primary school/secondary/high school/professional training; and working in the informal sector. In contrast, people who were male, healthcare personnel, high-income earners, participants who do not consume traditional herbal remedies, infected or knowing someone who has been infected by COVID-19, and having a chronic illness or comorbidity, were associated with COVID-19 vaccine acceptance. Participants also gave several reasons they were either hesitant or willing to take the vaccine. A more rigorous surveillance system is needed to systematically monitor drivers of vaccine hesitancy, establish tailored interventions promoting vaccine acceptance, and evaluate the impact of these interventions.

Commentary on COVID-19 Vaccine Hesitancy in sub-Saharan Africa.

Rates of vaccination against COVID-19 remain lower in sub-Saharan Africa than in other low and middle-income regions. This is, in part, attributed to vaccine hesitancy, mainly due to misinformation about vaccine origin, efficacy and safety. From August to December 2021, we gathered the latest experiences and opinions on four vaccine hesitancy-related areas (policies, perceived risk religious beliefs, and misinformation) from 12 sub-Saharan African researchers, four of whom have published about COVID-19 vaccine hesitancy. The authors included two political and business experts, six public health specialists, five epidemiologists, and four biostatisticians from ten sub-Saharan African countries( Cameroon, Ghana, Kenya, Liberia, Nigeria, Sierra Leone, South Africa, Tanzania, Uganda, and Zimbabwe). The authors' overarching opinions were that political influences, religious beliefs and low perceived risk exists in sub-Saharan Africa, and they collectively contribute to COVID-19 vaccine hesitancy. Communication strategies should target populations initially thought by policy makers to be at low risk, use multiple communication avenues and address major concerns in the population.

Macrofilaricidal Activity, Acute and Biochemical Effects of Three Lichen Species Found on Mount Cameroon.

Onchocerciasis is a parasitic infection affecting a relatively small population globally but has very devastating pathological outcomes. Ivermectin and recently moxidectin are the only drugs approved for clinical management of the disease, both of which have several limitations. In particular, they are efficacious against microfilariae (microfilaricidal) with no activity against adult worms (nonmacrofilaricidal). Promising anthelmintic activity has been reported in some lichens. This study investigated three lichens, Usnea articulata, Parmotrema tinctorum, and Heterodermia obscurata, found on Mount Cameroon, for potential macrofilaricidal activity. Organic extracts were screened for anti-Onchocerca activity against Onchocerca ochengi isolated from cattle skin using worm motility and MTT formazan assays. Toxicity of highly active extracts was investigated on monkey kidney epithelial (LLCMK2) cells and in BALB/c mice (2000 mg/kg body weight) including effects on liver enzymes. The methanol extract of P. tinctorum (Pammet) was the most active against adult male worms (IC50 = 8.1 µg/mL) with the highest selectivity index (SI = 21.3). U. articulata was the most active against the adult female (IC50 = 36.3 µg/mL) but had a low SI value (3.4). No mortality and no adverse effects were recorded in the acute toxicity test. These two most active extracts had no significant effect on liver enzymes, alanine aminotransferase, and aspartate (P values < 0.05), but a high AST : ALT ratio (2.59) for Pammet indicates likely reversible adverse hepatic toxicity. The high macrofilaricidal activity and selectivity of P. tinctorum suggest it is a potential source of new macrofilaricides which should be further investigated to identify its bioactive constituents.

Assessment of Vaccine Hesitancy to a COVID-19 Vaccine in Cameroonian Adults and Its Global Implication.

Since the outbreak of COVID-19 in December 2019, no global consensus treatment has been developed and generally accepted for the disease. However, eradicating the disease will require a safe and efficacious vaccine. In order to prepare for the eventual development of a safe and efficacious COVID-19 vaccine and to enhance its uptake, it is imperative to assess vaccine hesitancy in Cameroonians. After obtaining ethical clearance from the Institutional Review Board of the University of Buea, a questionnaire was administered (May-August 2020) to consenting adults either online or in person. A qualitative thematic analysis was done to analyze the participants' answers to the open questions. A deductive approach was used, that is, the codes and patterns according to the World Health Organization (WHO) Strategic Advisory Group of Experts (SAGE) Working Group Matrix of Determinants of vaccine hesitancy. The number of consenting adult Cameroonians who completed the questionnaire were 2512 (Two thousand five hundred and twelve). Vaccine hesitancy to a COVID-19 vaccine was 84.6% in Cameroonians. Using the WHO recommended Matrix of Determinant of Vaccine hesitancy, the most prominent determinants observed in this study were: Communication and Media Environment, Perception of pharmaceutical industry, Reliability and/or source of vaccine and cost. Most Cameroonians agree that even though there are benefits of a clinical trial, they will prefer it should be done out of the continent and involving African scientists for eventual acceptance and uptake. The concerns of safety, efficacy and confidence has to be addressed using a Public Engagement approach if a COVID-19 vaccine has to be administered successfully in Africa or Cameroon specifically. Since this study was carried out following WHO standards, its result can be compared to those of other studies carried out in different cultural settings using similar standards.

Analysis of the Role of TpUB05 Antigen from Theileria parva in Immune Responses to Malaria in Humans Compared to Its Homologue in Plasmodium falciparum the UB05 Antigen.

Despite the amount of resources deployed and the technological advancements in molecular biology, vaccinology, immunology, genetics, and biotechnology, there are still no effective vaccines against malaria. Immunity to malaria is usually seen to be species- and/or strain-specific. However, there is a growing body of evidence suggesting the possibility of the existence of cross-strain, cross-species, and cross-genus immune responses in apicomplexans. The principle of gene conservation indicates that homologues play a similar role in closely related organisms. The homologue of UB05 in Theileria parva is TpUB05 (XP_763711.1), which has been tested and shown to be associated with protective immunity in East Coast fever. In a bid to identify potent markers of protective immunity to aid malaria vaccine development, TpUB05 was tested in malaria caused by Plasmodium falciparum. It was observed that TpUB05 was better at detecting antigen-specific antibodies in plasma compared to UB05 when tested by ELISA. The total IgG raised against TpUB05 was able to block parasitic growth in vitro more effectively than that raised against UB05. However, there was no significant difference between the two study antigens in recalling peripheral blood mononuclear cell (PBMC) memory through IFN-γ production. This study suggests, for the first time, that TpUB05 from T. parva cross-reacts with UB05 from P. falciparum and is a marker of protective immunity in malaria. Hence, TpUB05 should be considered for possible development as a potential subunit vaccine candidate against malaria.

TpUB05, a Homologue of the Immunodominant Plasmodium falciparum Protein UB05, Is a Marker of Protective Immune Responses in Cattle Experimentally Vaccinated against East Coast Fever.

INTRODUCTION: East Coast fever, a devastating disease of cattle, can be controlled partially by vaccination with live T. parva sporozoites. The antigens responsible for conferring immunity are not fully characterized. Recently it was shown that the P. falciparum immunodominant protein UB05 is highly conserved in T. parva, the causative agent of East Coast fever. The aim of the present investigation was to determine the role of the homologue TpUB05 in protective immunity to East Coast fever. METHODS: The cloning, sequencing and expression of TpUB05 were done according to standard protocols. Bioinformatics analysis of TpUB05 gene was carried out using algorithms found in the public domain. Polyclonal antiserum against recombinant TpUB05 were raised in rabbits and used for further analysis by Western blotting, ELISA, immunolocalization and in vitro infection neutralization assay. The ability of recombinant TpUB05 (r-TpUB05) to stimulate bovine PBMCs ex-vivo to produce IFN-γ or to proliferate was tested using ELISpot and [3H]-thymidine incorporation assays, respectively. RESULTS: All the 20 cattle immunised by the infection and treatment method (ITM) developed significantly higher levels of TpUB05 specific antibodies (p<0.0001) compared to the non-vaccinated ones. Similarly, r-TpUB05 highly stimulated bovine PMBCs from 8/12 (67%) of ITM-immunized cattle tested to produce IFN-γ and proliferate (p< 0.029) as compared to the 04 naїve cattle included as controls. Polyclonal TpUB05 antiserum raised against r-TpUB05 also marginally inhibited infection (p < 0.046) of bovine PBMCs by T. parva sporozoites. In further experiments RT-PCR showed that the TpUB05 gene is expressed by the parasite. This was confirmed by immunolocalization studies which revealed TpUB05 expression by schizonts and piroplasms. Bioinformatics analysis also revealed that this antigen possesses two transmembrane domains, a N-glycosylation site and several O-glycosylation sites. CONCLUSION: It was concluded that TpUB05 is a potential marker of protective immunity in ECF worth investigating further.

Differential T-cell responses of semi-immune and susceptible malaria subjects to in silico predicted and synthetic peptides of Plasmodium falciparum.

Malaria remains a public health hazard in tropical countries as a consequence of the rise and spread of drug and insecticide resistances; hence the need for a vaccine with widespread application. Protective immunity to malaria is known to be mediated by both antibody and cellular immune responses, though characterization of the latter has been less extensive. The aim of the present investigation was to identify novel T-cell epitopes that may contribute to naturally acquired immune responses against malaria. Using the Microsoft software, Epitome™ T-cell peptide epitopes on 19 Plasmodium falciparum proteins in the Plasmodium Database (www.plasmodb.org.PlasmoDB 9.0) were predicted in-silico. The peptides were synthesized and used to stimulate peripheral blood mononuclear cells (PBMCs) in 14 semi-immune and 21 malaria susceptible subjects for interferon-gamma (IFN-γ) production ex-vivo. The level of IFN-γ production, a marker of T-cell responses, was measured by ELISPOT assay in semi-immune subjects (SIS) and frequently sick subjects (FSS) from an endemic zone with perennial malaria transmission. Of the 19 proteins studied, 17 yielded 27 pools (189 peptides), which were reactive with the subjects' PBMCs when tested for IFN-γ production, taking a stimulation index (SI) of ≥2 as a cutoff point for a positive response. There were 10 reactive peptide pools (constituting eight protein loci) with an SI of 10 or greater. Of the 19 proteins studied, two were known vaccine candidates (MSP-8 and SSP2/TRAP), which reacted both with SIS and FSS. Similarly the hypothetical proteins (PFF1030w, PFE0795c, PFD0880w, PFC0065c and PF10_0052) also reacted strongly with both SIS and FSS making them attractive for further characterization as mediators of protective immunity and/or pathogenesis.