Population dynamics of untreated Plasmodium falciparum malaria within the adult human host during the expansion phase of the infection

Parasitology ◽  
2002 ◽  
Vol 124 (3) ◽  
pp. 247-263 ◽  
Author(s):  
J. A. SIMPSON ◽  
L. AARONS ◽  
W. E. COLLINS ◽  
G. M. JEFFERY ◽  
N. J. WHITE
Keyword(s):  
Plasmodium Falciparum ◽  
Falciparum Malaria ◽  
Prediction Interval ◽  
Growth Dynamics ◽  
Plasmodium Falciparum Malaria ◽  
Host Susceptibility ◽  
Initial Growth ◽  
Multiplication Rate ◽  
Parasite Life Cycle ◽  
Parasite Multiplication

A retrospective analysis was performed of parasite count data recorded from the first 7 days of blood or mosquito transmitted Plasmodium falciparum infections given for the treatment of neurosyphilis in the USA before 1963. The objective of this study was to characterize initial growth dynamics before host defences have significant effects on the infecting parasite population. Of the 328 patients' data available for analysis, 83 were excluded because they had received anti-malarial treatment during the first 7 days of the patent infection. Nonlinear mixed effects modelling was performed to estimate the parameters of interest; ‘parasite multiplication rate per 48 h’ (PMR), and length of the parasite life-cycle (periodicity). The parasitaemia versus time profiles showed great variability between patients. The mean population estimate of ‘PMR’ was approximately 8, and was highly dependent on the P. falciparum ‘strain’. PMR also varied significantly between patients with a 90% prediction interval varying from 5·5 to 12·3-fold. Both intrinsic parasite multiplication rate (an intrinsic virulence determinant), and host susceptibility and defence contribute to expansion of the parasite biomass and thus disease severity in falciparum malaria.

Fever in the returning traveller: Dual infection with SARS-CoV-2 and Plasmodium falciparum malaria

2020 ◽  
pp. 105-108
Author(s):  
MA Parker ◽  
E Nell ◽  
A Mowlana ◽  
MS Moolla ◽  
S Karamchand ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Falciparum Malaria ◽  
Clinical Course ◽  
Febrile Illness ◽  
Plasmodium Falciparum Malaria ◽  
Dual Infection ◽  
Pneumocystis Pneumonia ◽  
Case Presentation ◽  
Presenting Symptoms ◽  
Uncomplicated Plasmodium Falciparum Malaria

Background: More than 90% of the global 400 000 annual malaria deaths occur in Africa. The current SARS-CoV-2 pandemic has resulted in more than 830 000 deaths in its first 10 months. Case presentation: This case describes a patient who had travelled from Mozambique to Cape Town, presented with a mild febrile illness, and was diagnosed with both COVID-19 and uncomplicated Plasmodium falciparum malaria infection. She responded well to malaria treatment and had an uneventful COVID-19 admission. Her blood smear showed a low malaria parasitaemia and a relatively high gametocyte load. Conclusion: We postulate that her clinical course and abnormal smear could well be due to reciprocal disease-modifying effects of the infections. The presenting symptoms of COVID-19 may mimic endemic infectious diseases including malaria, tuberculosis, pneumocystis pneumonia and influenza thus there is a need for clinical vigilance to identify and treat such co-infections.

scholarly journals Predictors of treatment failures of plasmodium falciparum malaria in Vietnam: a 4-year single‐centre retrospective study

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Minh Cuong Duong ◽  
Oanh Kieu Nguyet Pham ◽  
Phong Thanh Nguyen ◽  
Van Vinh Chau Nguyen ◽  
Phu Hoan Nguyen
Keyword(s):  
Plasmodium Falciparum ◽  
Treatment Failure ◽  
Severe Malaria ◽  
Falciparum Malaria ◽  
Control Strategies ◽  
Artemisinin Resistance ◽  
Plasmodium Falciparum Malaria ◽  
Molecular Technique ◽  
Drug Resistant ◽  
Public Health Burden

Abstract Background Drug-resistant falciparum malaria is an increasing public health burden. This study examined the magnitude of Plasmodium falciparum infection and the patterns and predictors of treatment failure in Vietnam. Methods Medical records of all 443 patients with malaria infection admitted to the Hospital for Tropical Diseases between January 2015 and December 2018 were used to extract information on demographics, risk factors, symptoms, laboratory tests, treatment, and outcome. Results More than half (59.8%, 265/443, CI 55.1–64.4%) of patients acquired Plasmodium falciparum infection of whom 21.9% (58/265, CI 17.1–27.4%) had severe malaria, while 7.2% (19/265, CI 4.6–10.9%) and 19.2% (51/265, CI 14.7–24.5%) developed early treatment failure (ETF) and late treatment failure (LTF) respectively. Among 58 patients with severe malaria, 14 (24.1%) acquired infection in regions where artemisinin resistance has been documented including Binh Phuoc (11 patients), Dak Nong (2 patients) and Gia Lai (1 patient). Under treatment with intravenous artesunate, the median (IQR) parasite half-life of 11 patients coming from Binh Phuoc was 3 h (2.3 to 8.3 h), two patients coming from Dak Nong was 2.8 and 5.7 h, and a patient coming from Gia Lai was 6.5 h. Most patients (98.5%, 261/265) recovered completely. Four patients with severe malaria died. Severe malaria was statistically associated with receiving treatment at previous hospitals (P < 0.001), hepatomegaly (P < 0.001) and number of inpatient days (P < 0.001). Having severe malaria was a predictor of ETF (AOR 6.96, CI 2.55–19.02, P < 0.001). No predictor of LTF was identified. Conclusions Plasmodium falciparum remains the prevalent malaria parasite. Despite low mortality rate, severe malaria is not rare and is a significant predictor of ETF. To reduce the risk for ETF, studies are needed to examine the effectiveness of combination therapy including parenteral artesunate and a parenteral partner drug for severe malaria. The study alerts the possibility of drug-resistant malaria in Africa and other areas in Vietnam, which are known as non-endemic areas of anti-malarial drug resistance. A more comprehensive study using molecular technique in these regions is required to completely understand the magnitude of drug-resistant malaria and to design appropriate control strategies.

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