Rapid Diagnostic Kits Research Articles

Seroprevalence of anti-SARS-CoV-2 specific antibodies in vaccinated and vaccine naïve adult Nigerians.

Reports on the evaluation of immune responses to different COVID-19 vaccines are limited. Similarly, effects of age and gender have not been well explored as variables that could impact on the vaccine-induced antibody response. Therefore, seroprevalence of anti-SARS-CoV-2 specific antibodies in vaccinated and vaccine naïve adult Nigerians was determined in this study. A total of 141 adults were enrolled into this study. Presence or absence of SARS-CoV-2 infection was confirmed by real-time reverse-transcriptase polymerase-chain reaction (RT-PCR) assay on nasopharyngeal and oropharyngeal swab specimens. Anti-SARS-CoV-2 Specific IgG and IgM antibodies were qualitatively detected using a Rapid Diagnostic Test kit. Pre-vaccination, 77% of the study participants had never had PCR-confirmed COVID-19 test yet 66.7% of them were seropositive for SARS-CoV-2 antibodies. Of 111 COVID-19 vaccinated participants, 69.2% and 73.8% of them had SARS-CoV-2 specific IgG post-first and second doses of COVID-19 vaccine respectively. However, 23.1% and 21.4% of the participants who have had first and second doses respectively had no detectable anti-SARS-CoV-2 antibodies. The proportion of participants with SARS-CoV-2 specific IgG was insignificantly higher in those between the ages of 18-40 years and 41-59 years compared with individuals aged ≥60 years. No significant association was observed between gender and seropositivity for SARS-CoV-2 antibodies. There is high SARS-CoV-2 antibody seroprevalence among Nigerian adults who never had PCR-confirmed COVID-19. Also, there is the need for anti-SARS-CoV-2 antibodies screening post vaccination as this could be essential in achieving herd immunity. Age and gender do not seem to have significant association with seropositivity.

Development, preparation, and evaluation of a novel dotted lateral flow immunochromatographic kit for rapid diagnosis of dermatophytosis

Dermatophytosis is a widely spread contagious zoonotic disease, affecting both man (tinea) and animals (ringworm). This disease is caused by a group of closely related keratinophilic fungi known collectively as the dermatophytes group. Although the wide distribution of dermatophytosis cases throughout the whole world and its adverse clinical effect on human health, economical effect on productive animals, and pet animal welfare, there is no rapid accurate diagnostic tool for such disease. The current conducted study tries to accomplish the difficult equation by achieving an accurate, sensitive, specific, user-friendly, rapid, robust, device-less, deliverable to end-users, and economic cost for the development and production of diagnostic kits. Through the development of a rapid diagnostic kit based on immunochromatographic assay with three major affordable reproducible production stages; preliminary stage, developmental and standardization stage, and evaluation stage. Obtaining dermatophytes-specific polyclonal antibodies against criteria-based selected dermatophytes strains associating proper gold nanoparticle preparation, characterization, and conjugation, with proper loading of the different bio-reactants on the efficiently laminated and fabricated lateral flow strips were the main challenge and control points through the whole process. Also, as a result of examining 100 animal samples using the new kit, the κ coefficients of the kit with the direct microscopy while the kit with the culture were 0.44 and 0.76, respectively. Therefore, the newly designated and developed kit showed a very promising competitive diagnostic result within 5–7 min through easy-to-be-performed three steps.

Hepatitis B Viral Load Patterns in HBsAg-Positive Antenatal Women and their Correlation with Stages of Pregnancy: A Cross-sectional Study

Introduction: Screening for Hepatitis B Surface Antigen (HBsAg) during pregnancy is essential, as maternal viremia is directly proportional to perinatal transmission. However, there is insufficient literature available on the viral load pattern of Hepatitis B Virus (HBV) in different trimesters of pregnancy. Aim: The aim of this study was to investigate the seroprevalence and estimate the viral load of HBsAg among antenatal women in different trimesters of pregnancy. Materials and Methods: A hospital-based cross-sectional study was conducted in the Department of Microbiology at Jorhat Medical College and Hospital in Jorhat, Assam, India, from June 2017 to May 2018. A total of 7833 samples were collected from antenatal cases attending the Outpatient Department of Obstetrics and Gynaecology. HBsAg positive cases were screened using a rapid diagnostic kit and Enzymelinked Immunosorbent Assay (ELISA). Viral load was estimated using Reverse Transcription Polymerase Chain Reaction (RTPCR) after obtaining written consent. Positive patients were followed up, and viral load estimation was repeated in each trimester. Statistical analysis was performed using Epi Info software and the Mann-Whitney U test. Results: The mean age of the HBsAg positive antenatal women who participated in the study was 25.97±3.72 years. Out of the 7833 patients screened, 32 antenatal patients were found to be positive for HBsAg. The highest viral load was found to be 1 log10 (25%) and 6 log10 (25%) IU/mL. The median viral load was highest in the second trimester at 1.434×106 IU/mL, followed by the third trimester at 7.003×105 IU/mL, and the first trimester at 43.6482 IU/mL. Conclusion: The pattern of HBV viral load indicates that patients in the first trimester either had borderline or low levels compared to those in the second and third trimesters. Since the viral load pattern varies in different trimesters of pregnancy, viral load estimation is crucial for the treatment of positive patients and to reduce HBV vertical transmissions.

Evaluation of utility of serological markers using rapid diagnostic test kits and investigating their correlation with peripheral blood count in a dengue fever outbreak

Evaluation of utility of serological markers using rapid diagnostic test kits and investigating their correlation with peripheral blood count in a dengue fever outbreak

Quality assurance of malaria rapid diagnostic tests: An aid in malaria elimination.

India targets malaria elimination by 2030 in a phased manner, so malaria's assured diagnosis is crucial. Introduction of rapid diagnostic kits in India in 2010 has revolutionized malaria surveillance. The storage temperature of rapid diagnostic tests (RDTs), kit components and handling in transportations impact the results of RDTs. Therefore, quality assurance (QA) is required before it reaches end-users. The Indian Council of Medical Research-National Institute of Malaria Research (ICMR-NIMR) has a World Health Organization (WHO) recognized lot-testing laboratory facility to assure the quality of RDTs. The ICMR-NIMR receives RDTs from different manufacturing companies as well as various agencies such as National and State Programmes and Central Medical Services Society. The WHO standard protocol is followed to conduct all the tests, including long-term and post-dispatch testing. A total of 323 lots tested during January 2014-March 2021 were received from different agencies. Amongst them, 299 lots passed the quality of test and 24 failed. In long-term testing, 179 lots were tested and only nine failed. A total of 7741 RDTs were received from end-users for post-dispatch testing of which 7540 qualified the QA test with a score of 97.4 per cent. RDTs received for quality testing showed compliance with QA evaluation of malaria RDTs based on the protocol recommended by the WHO. However, continuous monitoring of the quality of RDTs is required under QA programme. Quality-assured RDTs have a major role, especially in areas where low parasitaemia of parasites persists.

A study to assess knowledge of primary health workers on malaria epidemiology, diagnosis, and treatment in Patiala district, India

Background: India accounts for (4%) of all malaria cases worldwide. The World malaria report 2017 showed that, by 2016, global progress against malaria had stalled and was off track to meet the Global Technical Strategy milestones for 2020. Aims and Objectives: The aim of the study is to assess knowledge of rural medical officers (RMO) and health workers on malaria epidemiology, diagnosis, and treatment as per National Vector Borne Disease Control Program of India guidelines. Materials and methods: A descriptive, observational, and cross-sectional study was done among government health personnel’s using a semi-structured questionnaire. Results: In the present study, 258 health personnel’s participated comprising multipurpose health workers female (MPHW-F), multipurpose health worker male (MPHW-M), and RMO. The standardized score on knowledge of vector biology and epidemiology was 72% and 54% for RMO and (MPHW-M), respectively. On malaria diagnosis, MPHW-M has got median score (53%) as compared to RMO (46%). On national malaria drug policy, there is a marginal difference between median score of RMO (42%) and MPHW-M (40%). Overall, there is incomplete and poor knowledge of treatment of malaria among all health personnel’s with lack of concept about presumptive treatment. Training showed some positive impact on the knowledge of MPHW-F but no impact on MPHW-M. Graduates and experienced workers have got better knowledge than undergraduates and MPHW-M have more knowledge than MPHW-F. There is poor knowledge of reporting formats, and usage of rapid diagnostic kits among all the health personnels. There was no significant impact of education qualification, in service training and work experience on the knowledge of Male health workers. Conclusion: Training needs to be suitably tailored as there is a lot of scope of improvement in the knowledge regarding malaria diagnosis and treatment among health workers.

A COMPARATIVE STUDY OF THE DIFFERENT DIAGNOSTICS OF DETECTING MALARIA AND TYPHOID FEVER

Aim: The study is aimed at comparing the different method of diagnosing plasmodium parasite and typhoid fever and also to know the most effective method of diagnosis.
 Methods: The different diagnostic method of analyzing malaria and typhoid were compared by using blood and stool samples of patients from Angwan Rogo community FCT, Abuja. The diagnostic method used for the analysis of malaria were Rapid diagnostic test kit (RDT) and microscopy diagnostic method, which are Field stain and Giemsa stain. The positivity rate of RDT was (12%), Field stain (88%) and Giemsa stain (94%). Typhoid fever was diagnosed using widal test and stool culture test. The results showed that age group 1-10 had the highest malaria prevalence of 70% followed by age group 21-30 with prevalence of 10%. The positive result for typhoid fever widal test is 63.3% while for stool culture is 90%.
 Conclusion: The result of the study shows that children are more prevalent to malaria. Therefore, laboratory personnels should not depend solely on widal test, but rather they should employ other diagnostic method such as stool culture which can differentiate salmonella infections from other infections for more diagnostic test result.
 In diagnosis of analysing malaria and typhoid, microscopy and stool culture are more accurate and reliable.

Utilization of long lasting insecticidal net among children aged less than five years in a tertiary health facility in south-west Nigeria

ABSTRACT Introduction Long-lasting insecticidal nets (LLINs) are the most widely used vector control interventions for preventing malaria transmission. The study sought to determine the regular use of LLIN, factors associated with the usage and the effect of regular LLIN utilization on the development of malaria among under-five children. Methods This was a hospital-based cross-sectional observation study. We enrolled consecutive caregivers with their children aged 6 to 59 months who presented with fever in the absence of a localizing sign. A structured questionnaire was used to obtain information about the level of utilization of LLIN. Malaria parasitemia was detected using the P. falciparum rapid diagnostic test kit and/or microscopic examination of blood. Results A total of 303 children/caregivers pair was studied. The mother’s mean (SD) age was 37.17 (6.75) years, while the children was 24.36 (16.63) months. The majority (183; 60.4%) of the children were male. Parental awareness of LLIN was high (96.7%), LLIN ownership was 72.3%, however, only 119 (39.3%) were regular user of LLIN. Factors significantly associated with regular LLIN use were younger age, parental awareness, ownership of LLIN, source of acquisition of LLIN and permanently hanging the LLIN on sleeping space (p = 0.031, 0.010, 0.000, 0.006 and 0.000 respectively). Using binary logistic regression, the child’s age, source of LLIN and hanging the LLIN permanently on the bed remained statistically significant to the regular use of LLIN (p = 0.046, 0.035 and 0.000 respectively). The frequency of malaria was significantly higher among the children who did not use and those who uses LLIN irregularly (97.1% versus 32.9%, p = 0.000). Conclusions Regular use of LLIN is low in the study area. Hanging the insecticidal bed-net permanently on the bed/sleeping space promotes its regular usage. The frequency of malaria was reduced among the children using the LLIN regularly.

Challenges and Achievements in Fighting Infectious Diseases to Promote Sustainable Maternal and Child Health in Kenya - Multiplex Immunodiagnosis Solution for HIV, HBV, Syphilis among Fertile Women in Kenya -

In Kenya, the ‘Linda Mama Program’, a free care program for pregnant women, is being implemented, but as of 2017, maternal deaths per 100,000 live births reached 342, and the infection rate such as AIDS, hepatitis B, and syphilis is high. Diagnosis is being made centering on a quick simple test (rapid diagnosis), but the reliability is low, so an accurate and quick diagnosis method is needed. Through the Innovative Technology Program (CTS) of Korea International Cooperation Agency (KOICA), we developed a multi-immune diagnostic device and multi-diagnostic kit that can diagnose AIDS, hepatitis B, and syphilis, which can be tested with minimal education at schools and local public health centers in addition to hospitals. The sensitivity and specificity of the diagnostic kit were each 90% or more, which was improved by more than 20% compared to the rapid diagnostic kits. The supply of cost-competitive diagnostic devices and test kits will enable continuous monitoring of AIDS, hepatitis B, and syphilis infections among women of childbearing age between the ages of 15 and 49, thereby contributing to the improvement of maternal and child health.

OP08 Early Access To New Direct-Acting Antiviral: A Journey On Introduction Of Ravidasvir For Hepatitis C Treatment In Malaysia

IntroductionAccess to affordable direct-acting antiviral (DAA) remains limited in developing countries, often due to high treatment cost. This study aimed to elaborate the initiatives taken by the Ministry of Health Malaysia (MoHM) to provide early access to ravidasvir, a new DAA for hepatitis C treatment, in Malaysia.MethodsMoHM collaborated with Drugs for Neglected Diseases initiative (DNDi) to develop ravidasvir, a new chemical entity of oral non-structural protein 5A (NS5A) inhibitor. MoHM co-sponsored and participated the DNDi-led Phase II/III study (STORM-C-1 trial) to assess the efficacy and safety of ravidasvir-sofosbuvir combination therapy. Agreement was signed between Pharmaniaga, Pharco Pharmaceuticals and DNDi to register and supply affordable hepatitis C treatment in Malaysia and South-East Asia. MoHM and Pharmaniaga mutually worked on the registration of ravidasvir in Malaysia. Series of pre-submission meetings took place, rolling submission was allowed and conditional registration pathway was used. As a separate initiative, MoHM partnered with the Foundation for Innovative New Diagnostics (FIND) to implement decentralization and test-and-treat strategies for screening of hepatitis C virus (HCV).ResultsFirst stage of the STORM-C-1 trial reported that the combination of ravidasvir-sofosbuvir was highly effective across all genotypes and safe. The Drug Control Authority (DCA) Malaysia has granted a conditional registration for ravidasvir hydrochloride 200mg tablet (Ravida®) in June 2021, making Malaysia as the first country in the world to approve ravidasvir. Registration process expedited and took place within 15 months. The supply of Ravida® in Malaysia is expected in near future. Meanwhile, MoHM also implemented nationwide HCV screening using rapid diagnostic test kit in private hospitals, community clinics, prisons and rehabilitation centers which previously was done only in hospitals for outreach to the targeted group.ConclusionsRavidasvir-sofosbuvir has potential as a tool to eliminate hepatitis C in Malaysia by 2030, the WHO’s global elimination targets. This alternative new drug development model was successful due to strong leadership, public-private partnership and collaborative strategies. This could also be exercised in other disease area.

Performance analysis of polymerase chain reaction in relation to rapid diagnostic test (RDT) kit (SD bio line malaria ag p.f (05fk50)) for malaria diagnosis

Malaria control and its elimination heavenly depend on successful and reliable diagnosis using recommended diagnostic techniques. These available techniques often have certain peculiarities and mode applications, thus making them have different levels of performance and accuracy. Therefore the aim of this study was to evaluate the performance of PCR in relation to Rapid Diagnostic Test Kit (SD Bio line Malaria Ag P.f (05fk50)) in malaria diagnosis. A total of 200 blood samples were collected from the consented study subjects using the vein puncture technique and analysed using PCR and RDTs. Plasmodium falcifarum’s DNA was extracted using Quick-DNA™ Miniprep Plus Kit with catalog number D4069. 18SrRNA gene of Plasmodium falciparum from chromosome 13 was amplified using the two primers. For the RDTs technique, the SD Bio line Malaria Ag P.f (05fk50) test kit was used. Malaria prevalence of 106(53.0%) and 132(66.0%) were recorded using PCR and RDTs respectively. The PCR demonstrates an overall accuracy of 0.53 with sensitivity and specificity values of 56.06 and 52.94% respectively. The negative and positive predictive values were 69.81 and 38.30% respectively. PCR demonstrated a good level of performance and is therefore recommended as an effective diagnostic tool for malaria, especially in patients where the parasite density/parasitaemia level is very low.

Comparative laboratory diagnosis of malaria: Microscopy versus rapid diagnostic test kits in a tertiary institution of North-Central Nigeria

Comparative laboratory diagnosis of malaria: Microscopy versus rapid diagnostic test kits in a tertiary institution of North-Central Nigeria

Prevalence of HIV Sero-conversion and associated risk factors among antenatal clinic attendees in Enugu state university of science and technology teaching hospital, Enugu Nigeria

Background: Human immunodeficiency virus (HIV) infection is a leading cause of morbidity and mortality among women of reproductive age and it is a major contributor to maternal, infant and child morbidity and mortality. Globally, in 2015, an estimated, 78 million people had become infected with HIV while 35 million people had died from Acquired Immune Deficiency Syndrome (AIDS)-related illness since the start of the epidemic. In Nigeria, a national HIV prevalence rate of 3.4% was reported in 2012 with 1.3% in Enugu State. HIV retesting is a WHO recommendation that was adopted by Nigerian her national guideline. The essence of antenatal HIV retesting includes the identification of pregnant women who were first tested during their window periods and subsequently sero-converted, and those who acquired new HIV infection after their initial screening test given the fact that a single HIV testing may not be enough to diagnose HIV with findings of high rates of incident HIV infection during pregnancy and at the post-partum periods. It has been shown that the rate of MTCT was higher from sero-converting women compared with women with already established HIV infection. Hence, this study which gave a clue to the rate of HIV sero-conversion among our antenatal women which may possibly popularize the concept of retesting especially among these women. Aim: To determine the prevalence of HIV sero-conversion and the associated risk factors among previously sero-negative antenatal clinic attendees in Enugu State University of Science and Technology Teaching Hospital, (ESUTTH). Methods: This was a prospective, cohort study involving 415 sero-negative HIV women recruited from antenatal clinic in ESUTH from January to April, 2019 and followed up for 12 weeks. Information on their socio-demographic characteristics, pregnancy history, sexual lifestyle, and clinical profile were obtained using an interviewer-administered questionnaire. HIV tests were done at booking and repeated after 12 weeks using the Rapid Diagnostic Test kits by the parallel algorithm format. Data was analyzed with the IBM SPSS version 23.0. Measures of associations were determined with the Chi-Square test and binary logistic regression. P-value < 0.05 was assessed as statistically significant. Results: The mean age of the participants was 29.44±4.91SD years with a range of 16-43 years. Majority of them were married (397; 95.7%) and had post-secondary education (321; 77.3%). The incidence of HIV sero-conversion was 1.0%. Less than 35 years of age, being single, tobacco use, multiple sexual partners in pregnancy and knowledge of partners’ HIV status were significantly associated with HIV sero-conversion (p < 0.05). However, none of these factors was a significant predictor following logistic regression. Conclusion: The rate of HIV sero-conversion in pregnancy is of public health importance in Enugu and obligatory repeat testing, especially among women with these identified associated risk factors is therefore advised to forestall the menace of HIV to the child and the society at large.

Comparative laboratory diagnosis of malaria: Microscopy versus rapid diagnostic test kits in a tertiary institution of North-Central Nigeria

Laboratory diagnosis of malaria is a vital key for its effective management. Diagnosis of malaria includes rapid, sensitive, and specific test methods. This study was aimed to assess the diagnostic performance of PfHRP2 rapid malaria test with reference to light microscopy for the diagnosis of malaria at the Bingham University Teaching Hospital (BhUTH) Jos –Plateau State, Nigeria. A total of 150 febrile patients attending BHUTH who were sent to the Hospital Laboratory from the General out patients Department (GOPD) for malaria parasite test (MPT)request had their blood sample collected and tested for malaria parasites (MP) using Field Stain A and B stain microscopy and PfHRP2 rapid malaria test between September and November 2021.Results shows that the sensitivity and specificity of PfHRP2 rapid malaria were 9.23% and 90.0% respectively, with corresponding positive and negative predictive values (PPV) as 90.0%and (NPV) as13. 2%. PfHRP2 rapid malaria test showed good sensitivity and specificity that is in agreement with that of the reference light microscopy. The rapid diagnostic test (RDT) results compared well with the light microscopy (Gold standard) for Laboratory diagnosis for malaria. Sustained use of RDT as an alternative to light microscopy is recommended especially in malaria endemic areas and the rural communities where electricity is out of reach.

Multi-omics analysis reveals GABAergic dysfunction after traumatic brainstem injury in rats.

Traumatic brainstem injury (TBSI) is one of the forms of brain injury and has a very high mortality rate. Understanding the molecular mechanism of injury can provide additional information for clinical treatment. In this study, we detected transcriptome, proteomics, and metabolome expression changes in the brainstem of TBSI rats, and comprehensively analyzed the underlying mechanisms of TBSI. After TBSI, there was significant diffuse axonal injury (DAI) in the brainstem of rats. A total of 579 genes, 70 proteins, and 183 metabolites showed significant changes in brainstem tissue. Through molecular function and pathway analysis, the differentially expressed genes, proteins, and metabolites of TBSI were mainly attributed to neural signal regulation, inflammation, neuroprotection, and immune system. In addition, a comprehensive analysis of transcripts, proteins, and metabolites showed that the genes, proteins, and metabolic pathways regulated in the brainstem after TBSI were involved in neuroactive ligand-receptor interaction. A variety of GCPR-regulated pathways were affected, especially GAGA's corresponding receptors GABAA, GABAB, GABAC, and transporter GAT that were inhibited to varying degrees. This study provides insights into the development of a rapid diagnostic kit and making treatment strategies for TBSI.

Challenges with adherence to the ‘test, treat, and track’ malaria case management guideline among prescribers in Ghana

BackgroundDespite several efforts at addressing the barriers to adherence to the WHO-supported test, treat and track (T3) malaria case management guideline in Ghana, adherence remains a challenge. This study explored the challenges of prescribers regarding adherence to the T3 guideline.MethodsThis was an explorative study using key informant interviews amongst prescribers comprising medical doctors, physician assistants, nurses and a health extension worker from 16 health facilities in six districts in Ghana. The data was analysed using Nvivo 10 and organized into thematic areas.ResultsPrescribers lauded the guideline on testing and treatment as it ensures the quality of malaria case management, but irregular supply of malaria rapid diagnostic test kits (RDT), mistrust of laboratory tests, and the reluctance of prescribers to change from presumptive treatment were key barriers to testing. Patients with malaria test negative results if not treated, revisiting the facility with severe malaria, the experience of prescribers, lack of regular training and supervision for old and new staff and the inability of prescribers to investigate non-malaria fever hindered adherence to results-based treatment.ConclusionAs malaria remains a significant cause of morbidity and mortality in Ghana, this study provides insights on gaps in adherence to the testing and treatment of malaria. While the diagnostic capacity for malaria case management is a challenge, the lack of training resulting in the inability of some prescribers to investigate non-malaria fever hinders adherence to the malaria case management guideline. Therefore, there is a need to train new prescribers, laboratory personnel, and other staff involved in malaria diagnosis and treatment on the malaria case management guideline before they assume duty. Equipping laboratory personnel and prescribers with the knowledge to investigate non-malaria fevers could improve adherence to the guideline for improved patient care.

Comparison of different rapid screening tests and ELISA for HBV, HCV, and HIV among healthy blood donors and recipients at Jibla University Hospital Yemen

Blood transfusion is associated with many risks, especially exposure to blood transfusion-transmitted infections considered one of the main causes of death worldwide, including hepatitis B (HBV) and C virus (HCV) and human immunodeficiency virus (HIV). The threat posed by blood-borne pathogens is disproportionately high, especially in developing countries, so there is a need for continuous monitoring of blood transfusions to prevent transmitting diseases. Rapid diagnostic immunochromatographic technique (ICT) methods are the most widely used methods in developing countries, although ELISA and molecular testing are considered more accurate worldwide. Therefore, the study aimed to compare the analytical sensitivity between rapid tests and the ELISA method for detecting HBV, HCV, and HIV infection among blood donors. Four hundred (400) blood donor samples were tested using the Rapid Test Kits (INTEC, SD, ABON, and CLUN), and the ELISA method was used as a confirmatory test. Out of 400 blood samples tested for viral infection, HBV, HCV, and HIV were detected in 8, 10, and 2 samples, respectively, using the ELISA technique. This study observed that the rate of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), in addition to determining the diagnostic accuracy rate and error rate for all rapid diagnostic kits in detecting HBV, HCV and HIV are less accurate and associated with more false negatives compared to the ELISA technique. This study showed a significant difference in sensitivity between ELISA and rapid diagnostic immunochromatographic technique (ICT) groups; therefore, rapid diagnosis is not suitable for testing the quality of infectious markers for blood donors.

Utilization of 18s ribosomal RNA LAMP for detecting Plasmodium falciparum in microscopy and rapid diagnostic test negative patients.

In this study, Plasmodium falciparum was detected in patients that were declared negative for malaria microscopy and rapid diagnostic test kit (mRDT), using Plasmodium 18s rRNA loop-mediated isothermal amplification (LAMP) technique. The main aim of this study was to assess the usefulness of LAMP assay for detecting pre-clinical malaria, when microscopy and mRDT were less sensitive. DNA was obtained from 100 μL of whole blood using the boil and spin method. Subsequently, the Plasmodium 18s rRNA LAMP assay was performed to amplify the specific Plasmodium 18s rRNA gene. Microscopy and mRDT negative samples [697/2223 (31.2%)] were used for this study. Compared to frequencies obtained for the other demographic variables, most of the patients were < 6 years (37.7%), females (59.0%), peri-urban dwellers (39.0%) and patients that sought outpatient department services (39.3%). Overall, the prevalence of Plasmodium 18s rRNA was 17.5%. when stratified by study variables, Plasmodium 18s rRNA LAMP positivity was higher in patients over 30 years [58/122 (54.2%)], males [69/122 (56.5%)], rural dwellers [69/122 (56.5%)] and patients that sought OPD services [68/122 (55.7%)]. The risk of being infected with Plasmodium when routine tests were negative was higher in 15–30-year group (OR = 3.03, 95% CI: 1.6–5.8, p = 0.0007), patients > 30 years (OR = 15.2, 95% CI: 8.3–27.7, p<0.001), males (OR = 2.1, 95% CI: 1.4–3.2, p = 0.0002) and rural dwellers (OR = 2.2, 95% CI:1.4–3.6, p = 0.0009). However, risk was lower in post-natal children (OR = 0.3, 95% CI: 0.18–0.51, p<0.001). Majority (81.5%) of the infected patients presented with headache, herpes labialis, diarrhea and vomiting. We demonstrated the lack of sensitivities of microscopy and mRDT for one-time diagnosis of malaria. Therefore, it is essential to utilize a sensitive technique such as Plasmodium 18s rRNA LAMP to increase the detection rate of Plasmodium infection.

A colorimetric, sensitive, rapid, and simple diagnostic kit for the HLB putative causal agent detection

Huanglongbing (HLB) is one of the most devastating diseases in citrus worldwide. The Gram-negative bacterial plant pathogen “Candidatus Liberibacter spp.” is phloem-limited and vectored by citrus psyllids. The species “Candidatus Liberibacter asiaticus” (C.Las) has been detected in Argentina, and its vector has been found in at least nine provinces. Early detection of C.Las is critical for a successful management of HLB disease. Currently, HLB molecular diagnosis is carried out by PCR, nested PCR, real-time PCR, or another combination of these techniques, which require purification of genomic DNA, sophisticated equipment, and highly trained personnel. We have developed a prototype of a sensitive colorimetric kit to detect C.Las based on the specific DNA isothermal amplification of this microorganism. The reaction buffer contains hydroxynaphthol blue (HNB), an indicator dye that turns from violet to blue/light blue when the DNA amplification reaction is positive. Similar sensitivity to visualize a positive reaction was observed between HNB loop-mediated isothermal amplification and agarose gel electrophoresis analysis. The detection of C.Las-infected plants was up to 8 ng of total infected plant genomic DNA, similar to quantitative PCR. A blind validation test of the prototype kit was performed with purified DNA extracted from healthy or C.Las-infected midrib plants. Our kit showed 100% concordance with the results of a gold-standard quantitative PCR technique applied by the Laboratorio de Biología Molecular de EEA Montecarlo. The analysis of samples, without DNA purification to detect C.Las, showed a similar sensitivity to the analysis of the same samples in which C.Las DNA was previously purified.

Intermittent preventive treatment with Sulphadoxine-Pyrimethamine (IPTp-SP) is associated with protection against sub-microscopic P. falciparum infection in pregnant women during the low transmission dry season in southwestern Cameroon: A Semi - longitudinal study.

The current guidelines for malaria prevention and control during pregnancy in Africa is predicated on the prevention of infection and/or disease through intermittent preventive treatment in pregnancy (IPTp), insecticide-treated nets (ITNs) and effective malaria case diagnosis and management. Concerns that increasing SP resistance in some areas of SSA may have compromised IPTp-SP efficacy prompted this contemporaneous study, designed to assess the prevalence and risk factors of sub-microscopic infection in parturient women during the low transmission season in Mutengene, a rapidly growing semi-urban area in Southwest Region, Cameroon. Pregnant women originally reporting for the establishment of antenatal clinic care during the dry season were followed-up to term and their pregnancy outcomes recorded. About 2 ml of venous blood was collected for malaria diagnosis using PfHRP2/pLDH malaria rapid diagnostic kit and light microscopy. DNA was extracted from dried blood spots by the Chelex-100 method and the Plasmodium falciparum status detected by nested PCR amplification of the 18SrRNA gene using specific predesigned primers. Of the 300 women enrolled, the proportion of malaria parasite infected as determined by microscopy, RDT and PCR was 12.9%, 16.4% and 29.4% respectively, with 39.9% overall infected with P. falciparum by microscopy and/or RDT and/or PCR and a very low-density infection, averaging 271 parasites per microliter of blood. About 25.0% (68/272) of women who were negative by microscopy were positive by PCR (submicroscopic P. falciparum infection), with primigravidae and IPTp-SP non usage identified as independent risk factors for submicroscopic P. falciparum parasitaemia while fever history (aOR = 4.83, 95% CI = 1.28-18.22, p = 0.020) was associated with risk of malaria parasite infection overall. IPTp-SP use (p = 0.007) and dosage (p = 0.005) significantly influenced whether or not the participant will be malaria parasite negative or carry submicroscopic or microscopic infection. Although Infant birthweight and APGAR score were independent of the mother's P. falciparum infection and submicroscopic status, infant's birthweight varied with the gravidity status (p = 0.001) of the mother, with significantly lower birthweight neonates born to primigravidae compared to secundigravidae (p = 0.001) and multigravidae (p = 0.003). Even in holo-endemic dry season, there exists a large proportion of pregnant women with very low density parasitaemia. IPTp-SP seems to be relevant in controlling submicroscopic P. falciparum infections, which remains common in pregnant women, and are hard to diagnose, with potentially deleterious consequences for maternal and fetal health. Future studies should be carried out in hyperendemic malaria foci where the parasitemia levels are substantially higher in order to confirm the efficacy of IPTp-SP.