Malaria News Today 2020-10-21: perspectives on falciparum, transfusion issues, drug effectiveness

Ironically, blood transfusion helps with severe malaria, but can be dangerous in mild cases. And with severe malaria delay in treatment is a major risk. Malaria parasites can be surprisingly diverse, even in one home. Health system performance, drug quality and patient adherence are key factors in the effectiveness of anti-malarials. Read more on each article or abstract in the links provided.

The impact of delayed treatment of uncomplicated P. falciparum malaria on progression to severe malaria

Mousa A et al. conducted a systematic review and a pooled multicentre individual-patient meta-analysis in PLoS Medicine. Despite the reported association of delay in receiving treatment for uncomplicated malaria (UM) with an increased risk of developing severe malaria (SM), access to treatment remains low in most high-burden areas. Researchers performed a pooled individual-participant meta-analysis with the aim to ascertain the correlation between treatment delay and presenting with SM using Ovid MEDLINE and Embas.

Findings revealed significantly higher risk of severe disease in children and adults who had longer delays from symptom onset to treatment-seeking; this relationship was noted to be the strongest for progression to severe malarial anaemia. Per estimates, nearly half of the severe anaemia cases in both children and adults could be averted if they presented within the first 24 hours of symptom onset.

Malaria parasites in Nigeria are genetically diverse: a danger but also a useful tool

Segun Isaac Oyedeji notes that his team’s research has already confirmed that in malaria-endemic countries such as Nigeria, infected individuals carry P. falciparum parasites that are genetically complex or diverse. What we didn’t know was how diverse the parasites are in the micro environment, such as within households and among children of the same family.

Oyedeji thought that knowing the population structure within households could help us understand more about the pattern and development of the disease. It could also inform development of appropriate guidelines and control measures. He found that even in the micro environment, P. falciparum parasites exhibit high genetic diversity. This finding was similar to results from larger communities in malaria endemic regions and has the same important implications. The implication is that a one-size fits all intervention or approach against the parasites may not be effective. There were children living under the same roof and infected by parasites that were genetically different.

New evidence to guide the practice of blood transfusions in children with severe malaria

The Barcelona Institute for Global Health (ISGlobal) described a new study that shows that transfusions could help increase survival, even at higher haemoglobin levels than those currently recommended. The results show that blood transfusion increased the survival of patients with severe disease.

In cases with complications, such as impaired consciousness or elevated lactate in blood, transfusion improved survival even in children whose levels of haemoglobin were higher the recommended threshold of 60g /l. For example, among patients with impaired consciousness, the authors observed improved survival upon transfusion with haemoglobin levels as high as 105 g / l. However, in the case of mild cases, transfusion was associated with an increase in mortality.

Global estimation of anti-malarial drug effectiveness for the treatment of uncomplicated Plasmodium falciparum malaria 1991–2019

Giulia Rathmes and colleagues note that anti-malarial drugs play a critical role in reducing malaria morbidity and mortality, but their role is mediated by their effectiveness. Effectiveness is defined as the probability that an anti-malarial drug will successfully treat an individual infected with malaria parasites under routine health care delivery system. Anti-malarial drug effectiveness (AmE) is influenced by drug resistance, drug quality, health system quality, and patient adherence to drug use; its influence on malaria burden varies through space and time. This study used data from 232 efficacy trials.

The global effectiveness of artemisinin-based drugs was 67.4% (IQR: 33.3–75.8), 70.1% (43.6–76.0) and 71.8% (46.9–76.4) for the 1991–2000, 2006–2010, and 2016–2019 periods, respectively. The use of artemisinin-based combination therapy (ACT) with a competent partner drug and having multiple ACT as first-line treatment choice sustained high levels of effectiveness. High levels of access to healthcare, human resource capacity, education, and proximity to cities were associated with increased effectiveness. Effectiveness of non-artemisinin-based drugs was much lower than that of artemisinin-based.

This study provides evidence that health system performance, drug quality and patient adherence influence the effectiveness of anti-malarials used in treating uncomplicated falciparum malaria. These results provide guidance to countries’ treatment practices and are critical inputs for malaria prevalence and incidence models used to estimate national level malaria burden.

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