Search

Malaria rapid diagnostic tests (RDTs) targeting the Plasmodium falciparum histidine-rich protein 2 (PfHRP2) are widely used to diagnose P. falciparum infection. However, reports of P. falciparum strains lacking PfHRP2 and the structurally similar PfHRP3 have raised concerns about the utility and reliability of PfHRP2-based RDTs. This study investigated the presence of P. falciparum with pfhrp2 and/or pfhrp3 gene deletions among infected residents in the Lake Victoria region, Kenya. Four cross-sectional malaria, surveys were conducted in four sites (Suba South, Mfangano, Kibuogi, and Ngodhe) from September 2018 to January 2020. P. falciparum infections were detected using a PfHRP2-based RDT, microscopy, and PCR on 9120 finger-prick blood samples. Samples negative by RDT but positive by PCR were selected for PCR amplification of pfmsp1 and pfmsp2 to confirm the quality and quantity of P. falciparum DNA. Samples positive for both pfmsp1 and pfmsp2 were included for detection of deletions of exons 1 and 2 in pfhrp2 and pfhrp3 PCR. The multiplicity of infection (MOI) was determined as the higher allele count between pfmsp1 and pfmsp2. Logistic regression analysis was performed to analyze the association between pfhrp2 and/or pfhrp3 deletions and demographic and infection variables. Of the 445 RDT-negative and PCR-positive samples, 125 (28.1%) were analyzed for pfhrp2 and pfhrp3 deletions. Single pfhrp2 deletion, single pfhrp3 deletion, and pfhrp2/3 double deletions were detected in 13 (10.4%), 19 (15.2%), and 36 (28.8%) samples, respectively. Single pfhrp2 deletion was found in all sites while single pfhrp3 deletion was found in all sites except Kibuogi. The majority of samples with pfhrp2 and/or pfhrp3 deletions were submicroscopic (73.5%), asymptomatic (80.9%), and monoclonal (80.9%). Polyclonal infection was significantly (p = 0.022) associated with a lower odds of pfhrp2/3 double deletion, suggesting detection of intact pfhrp2/3 in mixed infections. We report the presence of P. falciparum with pfhrp2/pfhrp3 double deletions among asymptomatic and submicroscopic infections in Kenya. Our findings highlight the need for active monitoring of pfhrp2 and pfhrp3 deletions at the community level to improve malaria detection and control in the region. [ABSTRACT FROM AUTHOR]

Abstract Background Malaria-endemic countries are increasingly adopting data-driven risk stratification, often at district or higher regional levels, to guide their intervention strategies. The data typically comes from population-level surveys collected by rapid diagnostic tests (RDTs), which unfortunately perform poorly in low transmission settings. Here, a high-resolution survey of Plasmodium falciparum prevalence rate (PfPR) was conducted in two Tanzanian districts using rapid diagnostic tests (RDTs), microscopy, and quantitative polymerase chain reaction (qPCR) assays, enabling the comparison of fine-scale strata derived from these different diagnostic methods. Methods A cross-sectional survey was conducted in 35 villages in Ulanga and Kilombero districts, south-eastern Tanzania between 2022 and 2023. A total of 7,628 individuals were screened using RDTs (SD-BIOLINE) and microscopy, with two thirds of the samples further analysed by qPCR. The data was used to categorize each district and village as having very low (PfPR 50%. Prevalence varied by testing method: Kilombero was low risk by RDTs (PfPR = 3%) and microscopy (PfPR = 2%) but moderate by qPCR (PfPR = 9%); Ulanga was high risk by RDTs (PfPR = 39%) and qPCR (PfPR = 54%) but moderate by microscopy (PfPR = 26%). RDTs and microscopy classified majority of the 35 villages as very low to low risk (18–21 villages). In contrast, qPCR classified most villages as moderate to high risk (29 villages). Using qPCR as the reference, PPV for RDTs and microscopy ranged from as low as 80% in moderate and high transmission villages. Sensitivity was 62% for RDTs and 41% for microscopy; specificity was 93% and 96%, respectively. Kappa values were 0.7 for RDTs and 0.5 for microscopy. School-age children (5–15 years) had higher malaria prevalence and parasite densities than adults (P

Abstract Malaria rapid diagnostic tests (RDTs) targeting the Plasmodium falciparum histidine-rich protein 2 (PfHRP2) are widely used to diagnose P. falciparum infection. However, reports of P. falciparum strains lacking PfHRP2 and the structurally similar PfHRP3 have raised concerns about the utility and reliability of PfHRP2-based RDTs. This study investigated the presence of P. falciparum with pfhrp2 and/or pfhrp3 gene deletions among infected residents in the Lake Victoria region, Kenya. Four cross-sectional malaria, surveys were conducted in four sites (Suba South, Mfangano, Kibuogi, and Ngodhe) from September 2018 to January 2020. P. falciparum infections were detected using a PfHRP2-based RDT, microscopy, and PCR on 9120 finger-prick blood samples. Samples negative by RDT but positive by PCR were selected for PCR amplification of pfmsp1 and pfmsp2 to confirm the quality and quantity of P. falciparum DNA. Samples positive for both pfmsp1 and pfmsp2 were included for detection of deletions of exons 1 and 2 in pfhrp2 and pfhrp3 PCR. The multiplicity of infection (MOI) was determined as the higher allele count between pfmsp1 and pfmsp2. Logistic regression analysis was performed to analyze the association between pfhrp2 and/or pfhrp3 deletions and demographic and infection variables. Of the 445 RDT-negative and PCR-positive samples, 125 (28.1%) were analyzed for pfhrp2 and pfhrp3 deletions. Single pfhrp2 deletion, single pfhrp3 deletion, and pfhrp2/3 double deletions were detected in 13 (10.4%), 19 (15.2%), and 36 (28.8%) samples, respectively. Single pfhrp2 deletion was found in all sites while single pfhrp3 deletion was found in all sites except Kibuogi. The majority of samples with pfhrp2 and/or pfhrp3 deletions were submicroscopic (73.5%), asymptomatic (80.9%), and monoclonal (80.9%). Polyclonal infection was significantly (p = 0.022) associated with a lower odds of pfhrp2/3 double deletion, suggesting detection of intact pfhrp2/3 in mixed infections. We report the presence of P. falciparum with pfhrp2/pfhrp3 double deletions among asymptomatic and submicroscopic infections in Kenya. Our findings highlight the need for active monitoring of pfhrp2 and pfhrp3 deletions at the community level to improve malaria detection and control in the region.

Abstract Background Malaria is a worldwide infectious disease. For countries that have achieved malaria elimination, the prevention of re-establishment due to infections in returned travellers has become important. The accurate and timely diagnosis of malaria is the key in preventing re-establishment, and malaria rapid diagnostic tests (RDTs) are frequently used due to their convenience. However, the RDT performance in Plasmodium malariae (P. malariae) infection diagnosis remains unknown. Methods This study analysed epidemiological features and diagnosis patterns of imported P. malariae cases from 2013 to 2020 in Jiangsu Province and evaluated the sensitivity of four parasite enzyme lactate dehydrogenase (pLDH)-targeting RDTs (Wondfo, SD BIONLINE, CareStart and BioPerfectus) and one aldolase-targeting RDT(BinaxNOW) for P. malariae detection. Furthermore, influential factors were investigated, including parasitaemia load, pLDH concentration and target gene polymorphisms. Results The median duration from symptom onset to diagnosis among patients with P. malariae infection was 3 days, which was longer than that with Plasmodium falciparum (P. falciparum) infection. The RDTs had a low detection rate (39/69, 56.5%) among P. malariae cases. All tested RDT brands had poor performance in P. malariae detection. All the brands except the worst-performing SD BIOLINE, achieved 75% sensitivity only when the parasite density was higher than 5000 parasites/μL. Both pLDH and aldolase showed relatively conserved and low gene polymorphism rates. Conclusions The diagnosis of imported P. malariae cases was delayed. The RDTs had poor performance in P. malariae diagnosis and may threaten the prevention of malaria re-establishment from returned travellers. The improved RDTs or nucleic acid tests for P. malariae cases are urgently needed for the detection of imported cases in the future.

Background: Malaria is a worldwide infectious disease. For countries that have achieved malaria elimination, the prevention of re-establishment due to infections in returned travellers has become important. The accurate and timely diagnosis of malaria is the key in preventing re-establishment, and malaria rapid diagnostic tests (RDTs) are frequently used due to their convenience. However, the RDT performance in Plasmodium malariae (P. malariae) infection diagnosis remains unknown. Methods: This study analysed epidemiological features and diagnosis patterns of imported P. malariae cases from 2013 to 2020 in Jiangsu Province and evaluated the sensitivity of four parasite enzyme lactate dehydrogenase (pLDH)-targeting RDTs (Wondfo, SD BIONLINE, CareStart and BioPerfectus) and one aldolase-targeting RDT(BinaxNOW) for P. malariae detection. Furthermore, influential factors were investigated, including parasitaemia load, pLDH concentration and target gene polymorphisms. Results: The median duration from symptom onset to diagnosis among patients with P. malariae infection was 3 days, which was longer than that with Plasmodium falciparum (P. falciparum) infection. The RDTs had a low detection rate (39/69, 56.5%) among P. malariae cases. All tested RDT brands had poor performance in P. malariae detection. All the brands except the worst-performing SD BIOLINE, achieved 75% sensitivity only when the parasite density was higher than 5000 parasites/μL. Both pLDH and aldolase showed relatively conserved and low gene polymorphism rates. Conclusions: The diagnosis of imported P. malariae cases was delayed. The RDTs had poor performance in P. malariae diagnosis and may threaten the prevention of malaria re-establishment from returned travellers. The improved RDTs or nucleic acid tests for P. malariae cases are urgently needed for the detection of imported cases in the future. [ABSTRACT FROM AUTHOR]

Background: Rapid diagnostic tests based on detection of histidine-rich proteins (HRPs) are widely used for malaria diagnosis, but parasites carrying pfhrp deletions can evade detection and are increasing in frequency in some countries. Models aim to predict conditions under which pfhrp2 and/or pfhrp3 deletions will increase, but a key parameter-the fitness cost of deletions-is unknown.Methods: We removed pfhrp2 and/or pfhrp3 from a Malawian parasite clone using gene editing approaches) and measured fitness costs by conducting pairwise competition experiments.Results: We observed significant fitness costs of 0.087 ± 0.008 (1 standard error) per asexual cycle for pfhrp2 deletion and 0.113 ± 0.008 for the pfhrp2/3 double deletion, relative to the unedited progenitor parasite. Selection against deletions is strong and comparable to that resulting from drug resistance mutations.Conclusions: Prior modeling suggested that diagnostic selection may drive increased frequency of pfhrp deletions only when fitness costs are mild. Our experiments show that costs of pfhrp deletions are higher than these thresholds, but modeling and empirical results can be reconciled if the duration of infection is short. These results may inform future modeling to understand why pfhrp2/3 deletions are increasing in some locations (Ethiopia and Eritrea) but not in others (Mekong region). [ABSTRACT FROM AUTHOR]

Abstract Background Rural populations experience several barriers to accessing clinical facilities for malaria diagnosis. Increasing penetration of ICT and mobile-phones and subsequent m-Health applications can contribute overcoming such obstacles. Methods GIS is used to evaluate the feasibility of m-Health technologies as part of anti-malaria strategies. This study investigates where in Uganda: (1) malaria affects the largest number of people; (2) the application of m-Health protocol based on the mobile network has the highest potential impact. Results About 75% of the population affected by Plasmodium falciparum malaria have scarce access to healthcare facilities. The introduction of m-Health technologies should be based on the 2G protocol, as 3G mobile network coverage is still limited. The western border and the central-Southeast are the regions where m-Health could reach the largest percentage of the remote population. Six districts (Arua, Apac, Lira, Kamuli, Iganga, and Mubende) could have the largest benefit because they account for about 28% of the remote population affected by falciparum malaria with access to the 2G mobile network. Conclusions The application of m-Health technologies could improve access to medical services for distant populations. Affordable remote malaria diagnosis could help to decongest health facilities, reducing costs and contagion. The combination of m-Health and GIS could provide real-time and geo-localized data transmission, improving anti-malarial strategies in Uganda. Scalability to other countries and diseases looks promising.

Background: Rural populations experience several barriers to accessing clinical facilities for malaria diagnosis. Increasing penetration of ICT and mobile-phones and subsequent m-Health applications can contribute overcoming such obstacles. Methods: GIS is used to evaluate the feasibility of m-Health technologies as part of anti-malaria strategies. This study investigates where in Uganda: (1) malaria affects the largest number of people; (2) the application of m-Health protocol based on the mobile network has the highest potential impact. Results: About 75% of the population affected by Plasmodium falciparum malaria have scarce access to healthcare facilities. The introduction of m-Health technologies should be based on the 2G protocol, as 3G mobile network coverage is still limited. The western border and the central-Southeast are the regions where m-Health could reach the largest percentage of the remote population. Six districts (Arua, Apac, Lira, Kamuli, Iganga, and Mubende) could have the largest benefit because they account for about 28% of the remote population affected by falciparum malaria with access to the 2G mobile network. Conclusions: The application of m-Health technologies could improve access to medical services for distant populations. Affordable remote malaria diagnosis could help to decongest health facilities, reducing costs and contagion. The combination of m-Health and GIS could provide real-time and geo-localized data transmission, improving antimalarial strategies in Uganda. Scalability to other countries and diseases looks promising. [ABSTRACT FROM AUTHOR]

Copyright of Health Policy & Planning is the property of Oxford University Press / USA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Rapid diagnostic Tests (RDTs) for malaria enable diagnostic testing at primary care facilities in resource-limited settings, where weak infrastructure limits the use of microscopy. In 2010, Ghana adopted a test-before-treat guideline for malaria, with RDT use promoted to facilitate diagnosis. Yet healthcare practitioners still treat febrile patients without testing, or despite negative malaria test results. Few studies have explored RDT implementation beyond the notions of provider or patient acceptability. The aim of this study was to identify the factors directly influencing malaria RDT implementation at primary care facilities in a Ghanaian district. Methods: Qualitative interviews, focus groups and direct observations were conducted with 50 providers at six purposively selected primary care facilities in the Atwima–Nwabiagya district. Data were analysed thematically. Results: RDT implementation was hampered by: (1) healthcare delivery constraints (weak supply chain, limited quality assurance and control, inadequate guideline emphasis, staffing limitations); (2) provider perceptions (entrenched case-management paradigms, limited preparedness for change); (3) social dynamics of care delivery (expected norms of provider-patient interaction, test affordability); and (4) limited provider engagement in policy processes leading to fragmented implementation of health sector reform. Conclusion: Limited health system capacity, socio-economic, political, and historical factors hampered malaria RDT implementation at primary care facilities in the study district. For effective RDT implementation providers must be: (1) adequately enabled through efficient allocation and management of essential healthcare commodities; (2) appropriately empowered with the requisite knowledge and skill through ongoing, effective professional development; and (3) actively engaged in policy dialogue to demystify socio-political misconceptions that hinder health sector reform policies from improving care delivery. Clear, consistent guideline emphasis, with complementary action to address deep-rooted provider concerns will build their confidence in, and promote uptake of recommended policies, practices, and technology for diagnosing malaria. [ABSTRACT FROM AUTHOR]

Background In Zambia, there has been a large scaling up of interventions to control malaria in recent years including the deployment of rapid diagnostic tests (RDTs) to improve malaria surveillance data as well as guide malaria treatment in health facilities. The practical challenge is the impact of RDT results on subsequent management of patients. This study explored the role of RDTs in malaria diagnosis and the health workers' adherence to test results. Methods An observational prospective study was carried out at health centres in four districts, namely Chibombo, Chingola, Chipata, and Choma. Children under the age of five years with history of fever were recruited and the clinicians' use of RDT results was observed to establish whether prescriptions were issued prior to the availability of parasitological results or after, and whether RDT results influenced their prescriptions. Results Of the 2, 393 recruited children, 2, 264 had both RDT and microscopic results. Two in three (68.6%) children were treated with anti-malarials despite negative RDT results and almost half (46.2%) of these were prescribed Coartem®. Only 465 (19.4%) of the 2,393 children were prescribed drugs before receiving laboratory results. A total of 76.5% children were prescribed drugs after laboratory results. Children with RDT positive results were 2.66 (95% CI (2.00, 3.55)) times more likely to be prescribed anti-malarial drugs. Children who presented with fever at admission (although history of fever or presence of fever at admission was an entry criterion) were 42% less likely to be prescribed an anti-malarial drug compared to children who had no fever (AOR = 0.58, 95% CI (0.52, 0.65)). It was noted that proportions of children who were RDT- and microscopy-positive significantly declined over the years from 2005 to 2008. Conclusions RDTs may contribute to treatment of febrile illness by confirming malaria cases from nonmalaria cases in children under the age of five. However, the adherence of the health workers to prescribing anti-malarials to only RDT-positive cases at health facility level will still require to be explored further as their role is crucial in more precise reporting of malaria cases in this era towards malaria elimination as the target. [ABSTRACT FROM AUTHOR]

The article focuses on the performance of rapid diagnostic tests (RDT) for diagnosis of malaria at the China-Myanmar border area. It discusses the importance of RDT in malaria control and management programmes in the world. It states that the performance of RDT under different endemic conditions suggests its requirement for malaria diagnosis. It reports the effect of humidity and extreme temperatures on the performance of RDT.

Rapid diagnostic tests (RDTs) are used to diagnose malaria in Ghana and other malaria endemic countries. Plasmodium falciparum histidine-rich protein 2 (PFHRP2 ) based RDTs are widely used, however the occurrence of deletions of the pfhrp2 gene in some parasites have resulted in false negative test results. Monoclonal antibodies of PFHRP2 cross reacts with PFHRP3 because they share structural similarities and this complements the detection of the parasites by RDT. These two genes were investigated in Ghanaian P. falciparum parasite population to detect deletions and the polymorphisms in exon 2 of the pfhrp2 and pfhrp3 genes. Parasite isolates (2,540) from children ≤ 12 years with uncomplicated malaria from 2015 to 2020 transmission seasons were used. Both genes were amplified using nested PCR and negative results indicated the presence of the deletion of genes. Amplified genes were sequenced for the detection of the amino acid repeats. Deletions were observed in 30.7% (780/2,540) and 17.2% (438/2,540) of the samples for pfhrp2 and pfhrp3 respectively with increasing trends over the three time periods (χ2 -10.305, p = 0.001). A total of 1,632 amplicons were sequenced for each gene, analysis was done on 1,124 and 1,307 good quality sequences for pfhrp2 and pfhrp3 respectively. Pfhrp2 repeat polymorphisms were dominantly of types 2 (AHHAHHAAD) and 7 (AHHAAD) with large numbers of variants. A novel variant of type 14 (AHHANHATD) was seen for pfhrp2 . For the pfhrp3 repeat types, 16 (AHHAAN), 17 (AHHDG) and 18 (AHHDD) were the dominant types observed. Variants of type 16 (AHHAAH) and (AHHASH) were also dominant. Repeat types 1, 2, 3, 4, 5, 6, 7, 8, 11, 13, 15, 16, and 19 were observed be shared by both genes. The haplotype diversity of both genes ranged between 0.872 and 1 indicating high diversity of the polymorphisms in the isolates. The implication of the findings of the frequencies of the pfhrp2 and pfhrp3 deletions as well as the variants of the main epitopes of the monoclonal antibodies for the RDT (types 2 and 7) in our isolates is an indication of decreased sensitivity of the RDTs in diagnosing malaria infections in Ghana., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Duah-Quashie, Opoku-Agyeman, Bruku, Adams, Tandoh, Ennuson, Matrevi, Abuaku, Quashie, Watters, Wolfe, Quijada and Sanders.)

Background: Accurate diagnosis and prompt treatment of pregnancy-associated malaria (PAM) are key aspects in averting adverse pregnancy outcomes. Microscopy is the gold standard in malaria diagnosis, but it has limited detection and availability. When used appropriately, rapid diagnostic tests (RDTs) could be an ideal diagnostic complement to microscopy, due to their ease of use and adequate sensitivity in detecting even sub-microscopic infections. Polymerase chain reaction (PCR) is even more sensitive, but it is mainly used for research purposes. The accuracy and reliability of RDTs in diagnosing PAM was evaluated using microscopy and PCR. Methods: A cohort of pregnant women in north-eastern Tanzania was followed throughout pregnancy for detection of plasmodial infection using venous and placental blood samples evaluated by histidine rich protein 2 (HRP-2) and parasite lactate dehydrogenase (pLDH) based RDTs (Parascreen™ or HRP-2 only (Paracheck Pf® and ParaHIT®f), microscopy and nested Plasmodium species diagnostic PCR. Results: From a cohort of 924 pregnant women who completed the follow up, complete RDT and microscopy data was available for 5,555 blood samples and of these 442 samples were analysed by PCR. Of the 5,555 blood samples, 49 ((proportion and 95% confidence interval) 0.9% [0.7-1.1]) samples were positive by microscopy and 91 (1.6% [1.3-2.0]) by RDT. Forty-six (50.5% [40.5-60.6]) and 45 (49.5% [39.4--59.5]) of the RDT positive samples were positive and negative by microscopy, respectively, whereas nineteen (42.2% [29.0-56.7]) of the microscopy negative, but RDT positive, samples were positive by PCR. Three (0.05% [0.02-0.2]) samples were positive by microscopy but negative by RDT. 351 of the 5,461 samples negative by both RDT and microscopy were tested by PCR and found negative. There was no statistically significant difference between the performances of the different RDTs. Conclusions: Microscopy underestimated the real burden of malaria during pregnancy and RDTs performed better than microscopy in diagnosing PAM. In areas where intermittent preventive treatment during pregnancy may be abandoned due to low and decreasing malaria risk and instead replaced with active case management, screening with RDT is likely to identify most infections in pregnant women and out-performs microscopy as a diagnostic tool. [ABSTRACT FROM AUTHOR]

Abstract Background During pregnancy, malaria infection with Plasmodium falciparum or Plasmodium vivax is related to adverse maternal health and poor birth outcomes. Diagnosis of malaria, during pregnancy, is complicated by the absence or low parasite densities in peripheral blood. Diagnostic methods, other than microscopy, are needed for detection of placental malaria. Therefore, the diagnostic accuracy of rapid diagnostic tests (RDTs), detecting antigen, and molecular techniques (PCR), detecting DNA, for the diagnosis of Plasmodium infections in pregnancy was systematically reviewed. Methods MEDLINE, EMBASE and Web of Science were searched for studies assessing the diagnostic accuracy of RDTs, PCR, microscopy of peripheral and placental blood and placental histology for the detection of malaria infection (all species) in pregnant women. Results The results of 49 studies were analysed in metandi (Stata), of which the majority described P. falciparum infections. Although both placental and peripheral blood microscopy cannot reliably replace histology as a reference standard for placental P. falciparum infection, many studies compared RDTs and PCR to these tests. The proportion of microscopy positives in placental blood (sensitivity) detected by peripheral blood microscopy, RDTs and PCR are respectively 72% [95% CI 62-80], 81% [95% CI 55-93] and 94% [95% CI 86-98]. The proportion of placental blood microscopy negative women that were negative in peripheral blood microscopy, RDTs and PCR (specificity) are 98% [95% CI 95-99], 94% [95% CI 76-99] and 77% [95% CI 71-82]. Based on the current data, it was not possible to determine if the false positives in RDTs and PCR are caused by sequestered parasites in the placenta that are not detected by placental microscopy. Conclusion The findings suggest that RDTs and PCR may have good performance characteristics to serve as alternatives for the diagnosis of malaria in pregnancy, besides any other limitations and practical considerations concerning the use of these tests. Nevertheless, more studies with placental histology as reference test are urgently required to reliably determine the accuracy of RDTs and PCR for the diagnosis of placental malaria. P. vivax-infections have been neglected in diagnostic test accuracy studies of malaria in pregnancy.

Histidine-rich proteins 2 and 3 gene ( pfhrp2 and pfhrp3 ) deletions affect the efficacy of rapid diagnostic tests (RDTs) based on the histidine-rich protein 2 (HRP2), compromising the correct identification of the Plasmodium falciparum species. Therefore, molecular surveillance is necessary for the investigation of the actual prevalence of this phenomenon and the extent of the disappearance of these genes in these areas and other South American countries, thus guiding national malaria control programs on the appropriate use of RDTs. This study aimed to evaluate the pfhrp2 and pfhrp3 gene deletion in P. falciparum in endemic areas of the Brazilian Amazon. Aliquots of DNA from the biorepository of the Laboratory of Basic Research in Malaria, Evandro Chagas Institute, with a positive diagnosis for P. falciparum infection as determined by microscopy and molecular assays, were included. Monoinfection was confirmed by nested-polymerase chain reaction assay, and DNA quality was assessed by amplification of the merozoite surface protein-2 gene ( msp2). The pfhrp2 and pfhrp3 genes were amplified using primers for the region between exons 1 and 2 and for all extension of exon 2. Aliquots of DNA from 192 P. falciparum isolates were included in the study, with 68.7% (132/192) from the municipality of Cruzeiro do Sul (Acre) and 31.3% (60/192) from Manaus (Amazonas). Of this total, 82.8% (159/192) of the samples were considered of good quality. In the state of Acre, 71.7% (71/99) showed pfhrp2 gene deletion and 94.9% (94/99) showed pfhrp3 gene deletion, while in the state of Amazonas, 100.0% (60/60) of the samples showed pfhrp2 gene deletion and 98.3% (59/60) showed pfhrp3 gene deletion. Moreover, 79.8% (127/159) of isolates displayed gene deletion. Our findings confirm the presence of a parasite population with high frequencies of pfhrp2 and pfhrp3 gene deletions in the Brazilian Amazon region. This suggests reconsidering the use of HRP2-based RDTs in the Acre and Amazonas states and calls attention to the importance of molecular surveillance and mapping of pfhrp2/pfhrp3 deletions in this area and in other locations in the Amazon region to guarantee appropriate patient care, control and ultimately contribute to achieving P. falciparum malaria elimination.

Summary Testing and diagnosis of hepatitis C virus (HCV) infection is the gateway for access to both treatment and prevention services, and crucial for an effective hepatitis epidemic response. In contrast to HIV, a systematic approach to hepatitis C testing has been fragmented and limited to a few countries, and there remains a large burden of undiagnosed cases globally. Key challenges in the current hepatitis testing response, include lack of simple, reliable, and low cost diagnostic tests, laboratory capacity, and testing facilities; inadequate data to guide country-specific hepatitis testing approaches and who to test; stigmatization and social marginalization of some groups with or at risk of viral hepatitis; and lack of international or national guidelines on hepatitis testing for resource-limited settings. New tools to support the hepatitis global response include the 2016 Global Hepatitis Health Sector Strategy which include targets for testing and diagnosis, and World Health Organization (WHO) 2016 hepatitis testing guidelines for adults, adolescents, and children in low- and middle-income countries. The testing guidance complements recent published WHO guidance on the prevention, care and treatment of chronic hepatitis C and hepatitis B infection. These testing guidelines outline the public health approach to strengthening and expanding current testing practices for HCV and HBV and address what serological and virological assays to use, and who to test, as well as interventions to promote linkage to prevention and care after testing. They are intended for use across all age groups and populations. See boxes for key recommendations. Future directions and innovations in viral hepatitis testing include use of point-of-care assays for nucleic acid testing (NAT) and core antigen; validation of dried blood spots specimens with different commercial serological and NAT assays; multiplex and polyvalent platforms for integrated testing of HIV, HBV and HCV; and potential for self-testing. [ABSTRACT FROM AUTHOR]