Detection of Plasmodium using filter paper and nested PCR for patients with malaria in Sanliurfa, in Turkey

Misidentification of Plasmodium Species by Cross-Reacting Primers and Cerebral Malaria Caused by Plasmodium vivax

Introduction The clinical presentation of a case as cerebral malaria with molecular identification confirming it as Plasmodium vivax underlines the importance of using molecular tools to identify the species and type of malaria. The possibility of the relationship between the complication observed during clinical diagnosis and the multifactorial molecular changes could likely be the reason for terming it cerebral malaria.

Methods We report four cases analyzed using the quantitative buffy coat technique followed by classical Giemsa stained thick-film microscopy, and nested polymerase chain reaction for the genus-specific region of Plasmodium targeting 18S rDNA followed by species-specific identification with a different set of primers and products confirmation with sequencing.

Results Primers targeting P. knowlesi generated the expected product size of 153 base pairs that, upon sequencing, matched with the P. vivax sequence reflecting the relatedness of the species. Likewise, primers targeting P. ovale generated a 456 product whose sequence matched the P. vivax sequence.

Conclusion Infection with P. vivax can potentially cause cerebral malaria, and P. vivax can cause severe malaria complications alone or mixed with other species and can show cerebral malaria signs, which are typically associated with P. falciparum infections. The sequence relatedness reflects the genome similarity between P. knowlesi and P. ovale with P. vivax. The need to reconfirm with an additional set of newly reported primers is mandatory.

Application of machine and deep learning algorithms in optical microscopic detection of Plasmodium: A malaria diagnostic tool for the future

Machine and deep learning techniques are prevalent in the medical discipline due to their high level of accuracy in disease diagnosis. One such disease is malaria caused by Plasmodium falciparum and transmitted by the female anopheles mosquito. According to the World Health Organisation (WHO), millions of people are infected annually, leading to inevitable deaths in the infected population. Statistical records show that early detection of malaria parasites could prevent deaths and machine learning (ML) has proved helpful in the early detection of malarial parasites. Human error is identified to be a major cause of inaccurate diagnostics in the traditional microscopy malaria diagnosis method. Therefore, the method would be more reliable if human expert dependency is restricted or entirely removed, and thus, the motivation of this paper. This study presents a systematic review to understand the prevalent machine learning algorithms applied to a low-cost, portable optical microscope in the automation of blood film interpretation for malaria parasite detection. Peer-reviewed papers were downloaded from selected reputable databases eg. Elsevier, IEEExplore, Pubmed, Scopus, Web of Science, etc. The extant literature suggests that convolutional neural network (CNN) and its variants (deep learning) account for 41.9% of the microscopy malaria diagnosis using machine learning with a prediction accuracy of 99.23%. Thus, the findings suggest that early detection of the malaria parasite has improved through the application of CNN and other ML algorithms on microscopic malaria parasite detection.

Avian Malaria in Penguins: Diagnostics and Future Direction in the Context of Climate Change

Simple Summary

Avian malaria is caused by infection with protozoa of the genus Plasmodium. This vector-borne parasite is spread by mosquitoes and has a variable significance depending on environmental, host, mosquito and parasite factors. Captive penguins in non-native environments are exposed to the protozoa without having coevolved with them and are especially sensitive to infection. The most common presentation of the disease in affected penguins is acute death. Infection of wild penguins is reported and a greater understanding of the significance of such infections is required. Global warming and related surges in vector availability present an increasing threat to conservation in captive environments and targeted research into the early diagnosis of disease is required. Current diagnostic methods predominantly rely upon direct microscopy and/or molecular testing on tissues obtained from penguin postmortem examinations, and frequently fail to identify the causative agent at a species level. There are several barriers to the development of a rapid method to detect infection and the causative species; however, this information would further our understanding of this disease, and development of such a method is a valuable undertaking. This paper provides a summary of current diagnostic methods, identifies the likely future impacts of avian malaria in penguins, and highlights the need to improve both the speed and scope of available diagnostics.

Abstract

Avian malaria is caused by infection with haemoprotozoa of the genus Plasmodium. Infection is endemic in large parts of the world and is typically subclinical in birds that are native to these regions. Several penguin species have evolved in non-endemic regions without the selective pressure that these parasites exert and are highly susceptible to infection when transplanted to endemic regions, for example, in the context of zoological collections or rehabilitation centers. Avian malaria in penguins typically causes acute mortality without premonitory signs, or less commonly, nonspecific signs of morbidity, followed by mortality. Additionally, infection is reported in wild penguins, though the significance of these infections remains equivocal. As global temperatures continue to increase, avian malaria is likely to pose a continued and further threat to conservation efforts in captive environments. Intra vitam diagnosis currently relies on the evaluation of blood smears and molecular methods. The former is unreliable in penguins, as the acute clinical course typically does not allow the development of parasitemia. This absence of parasitemia also makes speciation challenging. Current molecular methods typically target the Cytochrome B or 18s subunit and have proven variably sensitive and specific. Reliable intra vitam diagnosis of avian malaria and further information about the causative agents at a species level would be very valuable in understanding the epidemiology and likely future course of avian malaria infection in penguins, and in particular, the implications avian malaria may have for conservation efforts. This paper provides an overview of malaria in penguins, discusses its changing impact on management and conservation, offers a summary of current diagnostics, and suggests future direction for the development of diagnostic tests. The latter will be key in understanding and managing this disease.

Molecular identification and anti-malarial drug resistance profile of Plasmodium falciparum from patients attending Kisoro Hospital, southwestern Uganda

Background

The evolution of malaria infection has necessitated the development of highly sensitive diagnostic assays, as well as the use of dried blood spots (DBS) as a potential source of deoxyribonucleic acid (DNA) yield for polymerase chain reaction (PCR) assays. This study identified the different Plasmodium species in malaria-positive patients, and the anti-malarial drug resistance profile for Plasmodium falciparum using DBS samples collected from patients attending Kisoro Hospital in Kisoro district, Southwestern Uganda.

Methods

The blood samples were prospectively collected from patients diagnosed with malaria to make DBS, which were then used to extract DNA for real-time PCR and high-resolution melting (HRM) analysis. Plasmodium species were identified by comparing the control and test samples using HRM-PCR derivative curves. Plasmodium falciparum chloroquine (CQ) resistance transporter (pfcrt) and kelch13 to screen the samples for anti-malarial resistance markers. The HRM-PCR derivative curve was used to present a summary distribution of the different Plasmodium species as well as the anti-malarial drug profile.

Results

Of the 152 participants sampled, 98 (64.5%) were females. The average age of the participants was 34.9 years (range: 2 months–81 years). There were 134 samples that showed PCR amplification, confirming the species as Plasmodium. Plasmodium falciparum (N = 122), Plasmodium malariae (N = 6), Plasmodium ovale (N = 4), and Plasmodium vivax (N = 2) were the various Plasmodium species and their proportions. The results showed that 87 (71.3%) of the samples were sensitive strains/wild type (CVMNK), 4 (3.3%) were resistant haplotypes (SVMNT), and 31 (25.4%) were resistant haplotypes (CVIET). Kelch13 C580Y mutation was not detected.

Conclusion

The community served by Kisoro hospital has a high Plasmodium species burden, according to this study. Plasmodium falciparum was the dominant species, and it has shown that resistance to chloroquine is decreasing in the region. Based on this, molecular identification of Plasmodium species is critical for better clinical management. Besides, DBS is an appropriate medium for DNA preservation and storage for future epidemiological studies.

Effectiveness of intermittent preventive treatment with Sulfadoxine-Pyrimethamine in pregnant women in San Pedro, Côte D'Ivoire

Malaria remains a major public health issue for pregnant women. Côte d'Ivoire has adopted a series of measures aimed at combatting this plague, and these measures include administering Sulfadoxine-Pyrimethamine (SP) as an intermittent preventive treatment to pregnant women in the second and third terms.This cross-sectional study included a parturient population after informed written consent. We recruited women from the Terre Rouge maternity ward and the labor room of the Regional Medical Center of San-Pedro. Plasmodial DNA (desoxyribo nucleic acid) was extracted from Whatman filter papers with dried blood samples prepared from the venous, placental, and cord blood, utilizing Chelex 100. The extracts obtained were amplified by nested PCR.In all, 197 women were included, with an average age of 27-year-old (sd = 6.7 years old). The rates of the placental, venous and cord blood infections were 16, 2%, 15, 2% and 3, 6%, respectively. The women who took three doses of ITP were less infected at the cord (3, 2%), placental (10,6%) and venous level (13,8%). A statistically significant relationship between the number of doses and the rate of placental infection was established (p = 0.042). IPT reduces plasmodial infestation at the placental (OR = 0.4; CI = [0.2-1]), cord (OR = 0.8; CI = [0.2-3.7]) and venous (OR = 0.8; CI = [0.6-2.3]) level.In conclusion, the low frequency of placental, venous, and cord infestation in pregnant women who consistently followed a preventive treatment strategy clearly showed the efficiency of IPT against malaria during pregnancy.

Utility of a Fluid Library with Samples of Humans, Reservoirs and Vectors Collected in Filter Paper, for Retrospective Diagnosis of American Trypanosomiasis in Endemic Areas of Venezuela

INTRODUCTION

We define a fluid library as a library of samples of different biological fluids (from humans, animals or vectors) collected and properly stored on filter paper, which allows retrospective studies, especially of diagnosis or detection of infectious agents in these samples, using different techniques. The objective of this work was the retrospective diagnosis of American trypanosomiasis by PCR in a Venezuelan endemic area using a fluid library.

METHODS

A fluid library with samples that had been collected on filter paper, 5 years ago, was used for the detection of Trypanosoma cruzi DNA. 165 blood samples of humans, 30 samples of 25 animals (Didelphis marsupialis, Canis familiaris, Equus asinus and Felis catus) and 8 samples of vectors from endemic areas of Anzoátegui state, were analysed by PCR.

RESULTS

The results revealed that 16.4% of the humans samples were positive, 11.1% of those detected positive were children younger than 10 years old, and 26.72% young people aged 11-20 years, suggesting that T. cruzi infection has been active for the past two decades. 56% of the animal samples showed amplification; Didelphis marsupialis 66%, Canis familiaris 54.5%, Equus asinus 50%, and Felis catus 33.3%. On the other hand, positivity (50%) was detected in the studied vectors, of which the 3 most important species in Venezuela (Rhodnius prolixus, Triatoma maculata and Panstrongylus geniculatus) were involved.

CONCLUSIONS

The PCR using a fluid library allowed the detection of T. cruzi DNA in old samples from the three host of the epidemiological chain, suggesting that retrospective diagnosis can be made through this strategy and demonstrate that there has been active transmission, which helps to clarify the epidemiological situation in areas where there are no previous reports.

Cutaneous Leishmaniasis due to Three Leishmania Species Among Syrian Refugees in Sanliurfa, Southeastern Turkey

Sanliurfa, a city in southeastern Turkey, is host to 477,166 Syrian refugees. The incidence of cutaneous leishmaniasis (CL) may be on the rise in areas affected by a refugee crisis, like Sanliurfa; thus, consequently, local uncommon species of Leishmania may be encountered in these regions. This might potentially make diagnosis and treatment more challenging over time. In this study, it was aimed to identify the causative agents of CL in clinical samples. A total of 154 patients (60 Syrian and 94 Turkish) who were diagnosed with CL via microscopical examination and PCR were enrolled this study. All of the samples were analyzed using internal transcribed spacer 1 genes, restriction fragment length polymorphism, DNA-sequencing, and phylogenetic analyses. In this study, Leishmania tropica was determined to be the predominant species in 140 of the patients (90.9%), followed by Leishmania major in 12 patients (7.8%), and Leishmania infantum in 2 patients (1.3%). Of the 94 Turkish patients, 94.7% were infected with L. tropica and 5.3% were infected with L. major, while none were infected with L. infantum. However, of the 60 Syrian patients, 85% were infected with L. tropica, 11.7% were infected with L. major, and 3.3% were infected with L. infantum. There was a significant association between the Leishmania species and the nations (Turkish-Syrian) (P < 0.001). The sequences were numbered from MH347941 to MH347953 and submitted to GenBank. This study confirmed that L. tropica, L. major, and L. infantum coexisted in Sanliurfa. This was the first time that the species L. infantum was reported among recent immigrants from Syria in Sanliurfa. Therefore, it is necessary to discriminate the Leishmania species for diagnosis, treatment, and controlled studies in hyper-endemic regions.

Point prevalence of asymptomatic Plasmodium infection and the comparison of microscopy, rapid diagnostic test and nested PCR for the diagnosis of asymptomatic malaria among children under 5 years in Ghana

BACKGROUND

Plasmodium infection among children is a serious public health problem. Asymptomatic malaria infection among humans serves as a significant reservoir for transmitting Plasmodium to uninfected Anopheles mosquitoes, fueling malaria endemicity and asymptomatic malaria may progress to clinical malaria. Therefore, prompt and accurate diagnosis of malaria infection is crucial for the management and control of malaria, especially in endemic areas. This study assessed the point prevalence of asymptomatic malaria infection and evaluated the performance of malaria Rapid Diagnostic Tests (RDT), light microscopy and nested PCR (nPCR) for the diagnosis of asymptomatic malaria infection in a paediatric population in the Atwima Nwabiagya North district, Ghana.

METHODS

This cross-sectional study enrolled 500 asymptomatic children aged ≤ 5 years. After consent was obtained from a parent, blood samples were collected from each participant to assess for Plasmodium infection based on histidine rich protein-2 (pfHRP-2)-based malaria RDT, light microscopy and nPCR.

RESULTS

The point prevalence of asymptomatic malaria by microscopy, RDT, and nPCR were 116/500 (23.2%), 156/500 (31.2%), and 184/500 (36.8%), respectively. Using nPCR as the reference, RDT presented with a perfect sensitivity (100.0%), specificity (100.0%), accuracy (100.0%), and reliability (100.0%) in detecting asymptomatic P. falciparum infection. Likewise, microscopy presented with an excellent specificity and high accuracy in detecting both P. falciparum (100.0%; 85.6%) and P. malariae (100.0%; 100.0%). However, the sensitivity (56.4%) and reliability (56.4%) of microscopy was low for both P. falciparum.

CONCLUSION

The findings of this study indicate a high point prevalence of asymptomatic Plasmodium infection among children in Atwima Nwabiagya North district, Ghana. In the absence of the more sensitive PCR, pfHRP-2-based malaria RDT provides substantial diagnostic sensitivity, specificity, accuracy and reliability and is superior to microscopy.

Characteristics of imported Plasmodium ovale spp. and Plasmodium malariae in Hubei Province, China, 2014-2018

Background

There have been an increasing number of imported cases of malaria in Hubei Province in recent years. In particular, the number of cases of Plasmodium ovale spp. and Plasmodium malariae significantly increased, which resulted in increased risks during the malaria elimination phase. The purpose of this study was to acquire a better understanding of the epidemiological characteristics of P. ovale spp. and P. malariae imported to Hubei Province, China, so as to improve case management.

Methods

Data on all malaria cases from January 2014 to December 2018 in Hubei Province were extracted from the China national diseases surveillance information system (CNDSIS). This descriptive study was conducted to analyse the prevalence trends, latency periods, interval from onset of illness to diagnosis, and misdiagnosis of cases of P. ovale spp. and P. malariae malaria.

Results

During this period, 634 imported malaria cases were reported, of which 87 P. ovale spp. (61 P. ovale curtisi and 26 P. ovale wallikeri) and 18 P. malariae cases were confirmed. The latency periods of P. ovale spp., P. malariae, Plasmodium vivax, and Plasmodium falciparum differed significantly, whereas those of P. ovale curtisi and P. ovale wallikeri were no significant difference. The proportion of correct diagnosis of P. ovale spp. and P. malariae malaria cases were 48.3% and 44.4%, respectively, in the hospital or lower-level Centers for Disease Control and Prevention (CDC). In the Provincial Reference Laboratory, the sensitivity of microscopy and rapid diagnostic tests was 94.3% and 70.1%, respectively, for detecting P. ovale spp., and 88.9% and 38.9%, respectively, for detecting P. malariae. Overall, 97.7% (85/87) of P. ovale spp. cases and 94.4% (17/18) of P. malariae cases originated from Africa.

Conclusion

The increase in the number of imported P. ovale spp. and P. malariae cases, long latency periods, and misdiagnosis pose a challenge to this region. Therefore, more attention should be paid to surveillance of imported cases of P. ovale spp. and P. malariae infection to reduce the burden of public health and potential risk of malaria.

Evaluation of malaria multiplex/nested PCR performance at low parasite densities and mixed infection in Iran: A country close to malaria elimination

BACKGROUND

Malaria is still a major public health problem in subtropical and tropical regions. The rapid and accurate diagnosis of malaria remains a challenge in most of the endemic areas. The primary objective of the present study was to evaluate the performance of multiplex/nested PCR in detecting Plasmodium falciparum at low parasite densities and mixed infection.

METHODS

The study was performed in the Sistan-Baluchestan province of the southeastern Iran, from May 2015 to July 2016. A total of 105 patients suspected to malaria infection were enrolled in the study. The obtained DNA products, extracted from the thick/thin films, were analyzed by multiplex/nested PCR using genus-specific primers and compared with light microscopy.

RESULTS

43 samples were confirmed to be infected by microscopic examination. Among 43 microscopically diagnosed P. falciparum cases, 11.4% (12/105) were confirmed by multiplex/nested PCR, 36.2% (38/105) were confirmed as P. vivax, 1.9% (2/105) had mixed infections with P. falciparum and P. vivax. Among microscopy-negative samples, 10 samples turned malaria-positive in nPCR. In multiplex/nested PCR, the rate of mixed infections was 8.6% (9/105). When compared to LM, the sensitivity, specificity, positive predictive value and negative predictive value of multiplex/nested PCR were calculated to be 82.8, 91.5, 92.3 and 81.1%, respectively.

CONCLUSION

In this study, we showed that microscopic examination of blood smears does not reliably distinguish Plasmodium species in the case of mixed infections. Therefore, it seems that multiplex/nested PCR is a good candidate for examining the presence of malaria parasites in clinically suspected but microscopically negative cases.

Molecular Screening for Malaria among Blood Donors in a WHO Claimed Region of Egypt, Fayoum Governorate

BACKGROUND

Transfusion-transmitted malaria is undoubtedly a potential health hazard for blood recipients. Egypt is still on the prevention of reintroduction phase of malaria control program. Fayoum Governorate is considered one of the high-risk foci in Egypt due to its geology. However, no studies have been reported to evaluate the current status of subclinical Plasmodium infection based on sensitive molecular techniques. Moreover, screening of malaria is not listed within screening protocols of blood-borne pathogens in Fayoum blood banks.

OBJECTIVE

To assess the current prevalence of subclinical Plasmodium infection among blood donors of Fayoum inhabitants for transfusion biosafety. To predict any possibility of the reemergence of malaria in the governorate and the effectiveness of malaria control measures.

METHODS

A cross-sectional survey was conducted on 400 apparently healthy blood-donors in blood transfusion center of Fayoum University hospital from Jun 2012 to Jan 2013. Conventional PCR was used to detect the 18 S ssrRNA Plasmodium gene.

RESULTS

All Fayoum inhabitants' blood donors' samples were negative for Plasmodium infection.

CONCLUSIONS

Current applied control, and preventive measures are valid in the context of blood transfusion biosafety in Fayoum blood banks and, therefore, the implementation of a routine malaria screening test in Fayoum blood banks is not merited at this time.