The life-threatening zoonotic malaria cases caused by Plasmodium knowlesi in Malaysia has recently been reported to be the highest among all malaria cases; however, previous studies have mainly focused on the transmission of P. knowlesi in Malaysian Borneo (East Malaysia). This study aimed to describe the transmission patterns of P. knowlesi infection in Peninsular Malaysia (West Malaysia). The spatial distribution of P. knowlesi was mapped across Peninsular Malaysia using Geographic Information System techniques. Local indicators of spatial associations were used to evaluate spatial patterns of P. knowlesi incidence. Seasonal autoregressive integrated moving average models were utilized to analyze the monthly incidence of knowlesi malaria in the hotspot region from 2012 to 2017 and to forecast subsequent incidence in 2018. Spatial analysis revealed that hotspots were clustered in the central-northern region of Peninsular Malaysia. Time series analysis revealed the strong seasonality of transmission from January to March. This study provides fundamental information on the spatial distribution and temporal dynamic of P. knowlesi in Peninsular Malaysia from 2011 to 2018. Current control policy should consider different strategies to prevent the transmission of both human and zoonotic malaria, particularly in the hotspot region, to ensure a successful elimination of malaria in the future.
Tiger's milk mushroom is known for its valuable medicinal properties, especially the tuber part. However, wild tuber is very hard to obtain as it grows underground. This study first aimed to cultivate tiger's milk mushroom tuber through a cultivation technique, and second to compare nutritional and mycochemical contents, antioxidant and cytotoxic activities and compound screening of the cultivated tuber with the wild tuber. Results showed an increase in carbohydrate content by 45.81% and protein content by 123.68% in the cultivated tuber while fat content reduced by 13.04%. Cultivated tuber also showed an increase of up to 64.21% for total flavonoid-like compounds and 62.51% of total β-D-glucan compared to the wild tuber. The antioxidant activity of cultivated tuber and wild tuber was 760 and 840 µg mL-1, respectively. The cytotoxic activity of boiled water extract of cultivated tuber against a human lung cancer cell line (A549) was 65.50 ± 2.12 µg mL-1 and against a human breast cancer cell line (MCF7) was 19.35 ± 0.11 µg mL-1. β-D-glucan extract from the purification of boiled water extract of cultivated tuber showed cytotoxic activity at 57.78 ± 2.29 µg mL-1 against A549 and 33.50 ± 1.41 µg mL-1 against MCF7. However, the β-glucan extract from wild tuber did not show a cytotoxic effect against either the A549 or MCF7 cell lines. Also, neither of the extracts from cultivated tuber and wild tuber showed an effect against a normal cell line (MRC5). Compound profiling through by liquid chromatography mass spectrometry (LC/MS) showed the appearance of new compounds in the cultivated tuber. In conclusion, our cultivated tuber of tiger's milk mushroom using a new recipe cultivation technique showed improved nutrient and bioactive compound contents, and antioxidant and cytotoxic activities compared to the wild tuber. Further investigations are required to obtain a better quality of cultivated tuber.
Introduction: Primaquine is vital for the management of liver-stagePlasmodium vivaxandPlasmodium ovalemalaria. However, primaquine effectiveness is dependent on various factors and differs between populations. Therefore, this study was conducted to identify factors that affect the length of stay and relapse during primaquine combination treatment in malaria-infected patients in the local setting.
Materials and Methods: A retrospective study on the use of primaquine combination amongP. vivaxandP. ovaleinfected patients in Selangor, Malaysia within a 5-year period from 2011 to 2015 was obtained from the National Malaria Case Registry, Malaysia. Data collected were patient characteristics (age, gender, nationality, glucose-6-phosphate dehydrogenase, pregnancy); disease characteristics (survival, past malaria infection, parasite type, presence of gametocyte, parasite count, week onset, severity, transmission type); and treatment characteristics (type of antimalarial, treatment completion). Outcome measures were length of stay and relapse during a 1-year follow-up.
Results: A total of 635 patients were included in the study. Based on a multivariate logistic regression analysis, the significant predictors for length of stay were gender (P= 0.009) and indigenous transmission (P< 0.001). Male patients had a shorter length of stay than females by 0.868 days (P= 0.009), and indigenous transmission took 1.82 days more compared to nonindigenous transmission (P< 0.001). Predictors for relapse were indigenous transmission of malaria (P= 0.019), which was 15.83 times more likely to relapse than nonindigenous transmission (P< 0.01).
Conclusions: This study reveals that the effectiveness of primaquine was clinically associated with gender and indigenous transmission. To that end, vigilant monitoring of primaquine use is required to reduce relapse and future transmission.
Plasmodium knowlesi is a simian malaria parasite that causes significant zoonotic infections in Southeast Asia, particularly in Malaysia. The Plasmodium thrombospondin-related apical merozoite protein (TRAMP) plays an essential role in the invasion of the parasite into its host erythrocyte. The present study investigated the genetic polymorphism and natural selection of the full length PkTRAMP from P. knowlesi clinical isolates from Malaysia. Blood samples (n = 40) were collected from P. knowlesi malaria patients from Peninsular Malaysia and Malaysian Borneo. The PkTRAMP gene was amplified using PCR, followed by cloning into a plasmid vector and sequenced. Results showed that the nucleotide diversity of PkTRAMP was low (π: 0.009). Z-test results indicated negative (purifying) selection of PkTRAMP. The alignment of the deduced amino acid sequences of PkTRAMP of Peninsular Malaysia and Malaysian Borneo revealed 38 dimorphic sites. A total of 27 haplotypes were identified from the amino acid sequence alignment. Haplotype analysis revealed that there was no clustering of PkTRAMP from Peninsular Malaysia and Malaysian Borneo.
The Plasmodium knowlesi secreted protein with an altered thrombospondin repeat (PkSPATR) is an important protein that helps in the parasite's invasion into the host cell. This protein has been regarded as one of the potential vaccine candidates against P. knowlesi infection. This study investigates the genetic diversity and natural selection of PkSPATR gene of P. knowlesi clinical isolates from Malaysia. PCR amplification of the full length PkSPATR gene was performed on 60 blood samples of infected P. knowlesi patients from Peninsular Malaysia and Malaysian Borneo. The amplified PCR products were cloned and sequenced. Sequence analysis of PkSPATR from Malaysia showed higher nucleotide diversity (CDS p: 0.01462) than previously reported Plasmodium vivax PvSPATR (p = 0.0003). PkSPATR from Peninsular Malaysia was observed to have slightly higher diversity (CDS p: 0.01307) than those from Malaysian Borneo (CDS p: 0.01212). Natural selection analysis on PkSPATR indicated significant purifying selection. Multiple amino acid sequence alignment revealed 69 polymorphic sites. The phylogenetic tree and haplotype network did not show any distinct clustering of PkSPATR. The low genetic diversity level, natural selection and absence of clustering implied functional constrains of the PkSPATR protein.