In Malaria World this week there is an article ‘Exploring the prevalence and association between nutritional status and asymptomatic malaria in Rwanda among under-5 children: a cross-sectional analysis’ by Uwimana et al describes the association between malaria and malnutrition.  

Data from three Demographic and Health Surveys (DHS) conducted in Rwanda in 2010, 2014–15, and 2019–20 were used in the study, including children aged 6 to 59 months and confirmed malaria diagnoses via blood smear. Asymptomatic malaria was found to be present in 1.3% of the population. The results indicate that malaria was more frequent in children with stunting. Underweight children were also found to have an increased prevalence of malaria. Children from the richest families were found to be protected from malaria in all 3 DHS.

In Malaria World this week there is another paper highlighting the effect of socio-economic inequalities in malaria prevalence, ‘Socio-economic inequalities in malaria prevalence among under-five children in Ghana between 2016 and 2019: a decomposition analysis’ by Edusei et al. In their analysis of results from 2019 Ghana Malaria Indicator Surveys (GMIS) of under-five children the concentration index (Concentration Index = − 0.224; Standard Error = 0.059; p-value = 0.000) was statistically significant and negative, indicating higher malaria prevalence among children from lower socio-economic backgrounds.

The study found socioeconomic status related inequalities in malaria prevalence to the disadvantage of poorer under-five children, highlighting the significant role played by socioeconomic status, maternal education, regional disparities, and rural residency.

Other articles on interest in Malaria World this week include a discussion of Bill Gates announcement that he plans to wind up the Gates Foundation and a discussion of the 1922 Zionist launch of sustainable malaria control and an examination of the education which enabled that control.

In Malaria World this week there is a review ‘Global trends and burdens of neglected tropical diseases and malaria from 1990 to 2021: a systematic analysis of the Global Burden of Disease Study 2021’ by Chen et al. Its introduction has an interesting un-cited statement ‘Malaria, commonly referred to as the “disease of poverty”’. The paper itself which is a review of trends over the 31 year period has data that shows that the incidence, prevalence, deaths and DALY (disability adjusted life years) have decreased over the timeframe.

But most interestingly it had a figure that shows that the effect on DALY (disability adjusted life years) for neglected tropical diseases and malaria is strongly dependent on SDI (sociodemographic index). These data strongly support the statement above.

A search of the internet provides more evidence. Even the UN for World Malaria Day in 2023 have published a web article entitled ‘Malaria: a disease of poverty’. Gallup and Sachs (Jeffrey) wrote ‘The Intolerable Burden of Malaria: A New Look at the Numbers: Supplement to Volume 64(1) of the American Journal of Tropical Medicine and Hygiene’ the first line of which is ‘Malaria and poverty are intimately connected’. These articles do maintain the mosquito connection, but state that the reasons for the connection with poverty are unclear. Mosquitos do not differentiate between rich and poor. So perhaps malaria has other causes?

An article in Malaria World this week, ‘Lessons from failure to success on malaria elimination in the Huai River Basin in China’ by Liu et al has interesting data of the rates of malaria from Yongcheng City and Guoyang County, Huai River Basin, China (1955-2023). What is very notable is how dramatically incidence declined from very high peaks around 1960 during the Great Chinese Famine (1959-1961) and 1970 during the cultural revolution (1966-1976) to practically no malaria 1983-2023, apart from a small increase from 2003-2008 (see figure).

The Cultural Revolution was characterized by violence and chaos across Chinese society. Estimates of the death toll vary widely, typically ranging from 1–2 million, including a massacre in Guangxi that included acts of cannibalism, as well as massacres in Beijing, Inner Mongolia, Guangdong, Yunnan, and Hunan.

The Great Chinese Famine was a famine that occurred between 1959 and 1961 as a result of policies of the Mao’s Great Leap Forward. It is widely regarded as the deadliest famine and one of the greatest man-made disasters in human history, with an estimated death toll due to starvation that ranges in the tens of millions (15 to 55 million). The Tibetan government in exile claimed that many Tibetans died from famines in 1961–1964 and 1968–1973 as a result of forced collectivization.

This particular ‘elephant in the room’ linking malaria incidence to famine is ignored by the authors who concentrate their discussion on the slight increase from practically zero to ~600 cases per 100,000 (0.6%) in Guoyang County in 2006. In 1970 there were 18,000/100,000 cases (18%) in Guoyang County in and 33,000/100,000 (33%) in Yongcheng City. This slight increase 2003-2008 was blamed on merger or closure of malaria control facilities, loss of medical professionals, low capacity for detection, diagnosis, prevention, and management of malaria cases, and underestimating the transmission potential of Anopheles sinensis. The Chinese authorities reacted to these deficiencies following typical Health Authority malaria control methods and consider that these reversed the decline. Increases of malaria budgets are considered particularly important.

As usual the linkage of malaria to malnutrition was ignored.

Malaria World this week includes a reference to a protocol of a very interesting literature review to be carried out. ‘Integrated malaria vector control strategies and their effectiveness in sub-Saharan Africa: a systematic review protocol for interventional studies’ by Kombate et al will systematically retrieve published and grey literature from electronic databases and clinical trial registries. A meta-analysis will be conducted based on studies that have reported a high level of evidence.

The study will look for interventions that integrate malaria-specific vector control approaches. This implies a combination of two or more of the following strategies:

• ITNs (insecticide treated nets)
• Installation of screens on windows
• Ventilation openings and open roof eaves to prevent mosquitos from entering homes
• Closing windows and doors at sunset to reduce mosquito entry into homes
• IRS (indoor residual spraying)
• Environmental management and source reduction
• LSM (larval source management)
• Topical and spatial mosquito repellents
• Mosquito coils
• Insecticide sprays

The control data will be provided by studies with a comparator or control group using single-intervention strategies or no intervention.

The target outcomes are

• Malaria incidence: measured as the number of new cases of malaria diagnosed in a specific population over a given period of time.
• Malaria prevalence: measured as the proportion of surveyed children and pregnant women who are infected with malaria at a specific point in time at the community level.

The analysis will include papers published in English and French from 01 January 2004 and 01 May 2024. It will include cluster-randomised controlled trials (RCTS), cluster-randomised studies using a stepped-wedge design, cluster-randomised cross-over studies, cohort studies (prospective or retrospective), non-randomised cross-over studies, controlled before and after studies, programmatic evaluations, cross-sectional studies, case–control studies, interrupted time series, and case series.

The analysis will use the accepted methods for similar meta-analyses which are fully described in the protocol.

I look forward to the resulting paper when the study is complete. I previously discussed a Cochrane review that examined the effect of indoor residual spraying and found no convincing evidence of its effectiveness. It will be interesting to see what this study focusing on multiple vector control methods finds. If malaria is spread by mosquitos reducing their number and the number of bites should reduce incidence and prevalence?

‘Relationship between unimproved household sanitation facilities and malaria infection among under‑five children in Nigeria: insights from Malaria Indicator Survey 2021’, by Asifat et al, in this weeks Malaria World has interesting insights on factors associated with malaria. They found that the type of toilet facility, unimproved versus improved was strongly associated with occurrence of malaria, measured with RDT (rapid diagnostic tests) on children under five years, (3.766 odds ratio). However, this was not significantly associated with malaria (1.297, 95% Confidence interval 0.898–1.875) after adjusting for socioeconomic and demographic factors.

Improved sanitation means flush toilets and unimproved includes pit latrines without slabs, open defecation, and other forms. There is a strong association with occurrence of malaria, but correlation does not indicate causation. Because as rightly pointed out by the authors, unimproved sanitation is associated with poverty, rural residence, and less maternal education. Poor children with less educated mothers living in rural locations are more likely to have malaria and to only have unimproved sanitation facilities. Other factors that were found to be associated with occurrence of malaria were accommodation with unimproved wall materials and roof materials. These factors are also associated with poverty.

One factor that surprised me was that the drinking water source was not significantly associated with occurrence of malaria. Drinking water sources were classified according to the WHO/UNICEF Joint Monitoring Programme (JMP) framework: 4.5% safely managed water (piped into dwelling), 64.0% basic water (protected wells, boreholes, public taps), 24.4% unimproved water (unprotected wells, tanker trucks), and 7.1% surface water (rivers, lakes, canals). Surface water compared to safely managed water has 3.183 times more malaria. However, both are small numbers in the sample and are also associated with wealth. Most subjects have basic water or unimproved water, the quality of which is unknown without testing.

So, what is the factors that increase susceptibility to malaria? It is most likely related to poverty. There is no discussion of nutrition in this paper. The quality of nutrition is likely associated with wealth and the education level of the mother. It is a factor that merits more attention.

Several weeks ago I addressed the issue of asymptomatic malaria and had also addressed it a year ago. I am not convinced that asymptomatic malaria is an illness. Most malaria researchers with their parasite model will argue that they are ‘cases’. However, I would love to see how many cases a method such as that described in Malaria World this week would find in a ‘malaria free’ country. But don’t expect that type of control experiment any time soon.

What surprised me most about ‘Asymptomatic malaria reservoirs are the last challenge in the elimination in Cambodia’ by Doum et al was how low the case numbers were. And they used PCR (polymerase chain reaction) as the detection technique. We remember that PCR was used extensively during the COVID19 pandemic and was criticised because, if a large number of cycles were used, it had a high false positive level. Many of the ‘cases’ detected were asymptomatic.

The paper summary states that all qPCR-diagnosed cases were asymptomatic. Malaria cross-sectional surveys were conducted in high-risk populations (forest dwellers, forest goers and forest rangers) at three different time (T0, T1, T2) from October 2022 to February 2023, overlapping the rainy, malaria transmission season and into the dry season. In Mondulkiri, the prevalence of Plasmodium falciparum was 0.63% at T0, increasing to 0.81% at T1, and decreasing to 0.18% at T2. Plasmodium vivax decreased from 4.80% at T0 to 1.97% at T1 and 1.65% at T2. In Kampong Speu, overall prevalence was 7.06% at T0, declining to 5.19% at T1 and 4.59% at T2. Plasmodium falciparum prevalence was 0.30% at T0, decreasing to 0.09% at T1 and rising slightly to 0.10% at T2. The forest goers showed a prevalence increase to 1.95% at T1 and decrease to 1.46% by T2, while forest dwellers decreased to 3.25% at T1 and further to 3.13% at T2.

Just like with COVID RDTs (rapid diagnostic tests) were less likely to be positive. Passively reported malaria cases showed 1.09% of cases in Mondulkiri and 0.21% of cases in Kampong Speu were rapid diagnostic test (RDT) positive.

This study was carried out on high-risk populations and all cases were asymptomatic. RDTs had 1% positivity or less. With PCR higher numbers were detected but all were still <10%. It would seem to me that a case could be made that malaria has now been eliminated from Cambodia, if this is as bad as it gets. I repeat it would be interesting to see how many positive cases there would be in a similar study in a malaria free country.

WHO and other organisations promote the use of insecticide treated bednets (ITN) to prevent malaria. The use of nets is based on the hypothesis that malaria is spread by mosquito bites and nets prevent bites. Insecticide treated nets not only prevent a mosquito from biting someone sleeping underneath but also kill any insect that lands on them. WHO claim that if ITNs are in widespread use the reduction in insect numbers reduces overall malaria burden. I am unaware of any studies that prove this hypothesis.

However, an analysis in Malaria World this week on the 2019 Ghana Malaria Indicator Survey had a clue that sleeping under bednets has no benefit. ‘Malaria prevalence dynamics and risk covariates among children under 5 in Ghana: insights from a Bayesian multilevel approach’ by Asosega et al has several interesting findings. Children in wealthier homes are less likely to test positive for malaria than those with poor or middle incomes (P=0.24 vs 0.32). Children with severe anaemia (low iron) are more likely to test positive than those mild or not anaemic (P=0.54 vs 0.26). These data may suggest that children who are better fed are less likely to have malaria.

And there was no significant benefit associated with sleeping under an ITN (P=0.29 vs 0.30). In households that owned bednets there was slightly less malaria (P=0.29 vs 0.32) but this is not significant either. But most interesting of all was a reference in the discussion to ‘Factors associated with the risk of malaria among children: analysis of 2021 Nigeria Malaria Indicator Survey’ by Isiko et al published in April 2024 that found that having a bednet for sleeping under was positively associated with malaria incidence (P=0.1848 vs 0.1280). The authors explain the result by suggesting ‘… a potential over-reliance on ITNs as the sole preventive measure, neglecting other malaria prevention strategies’. Perhaps breathing air that has passed through an insecticide treated net is not healthful. Or perhaps it is just a random result?

There are a number of other interesting findings in this Nigeria study which concur with my earlier postings Occurrence of Malaria associated with Poverty – Tanzania Study and Study in Ghana Suggests Poverty is the Major Factor in Occurrence of Malaria. Higher malaria associated with other water source than improved source (P=0.2484 vs 0.1552), rudimentary wall than finished wall (P=0.2253 vs 0.1348), primary than secondary education of mother (P=0.1923 vs 0.1366) and lower wealth index poor (P=0.1870) vs rich (P=0.1315).

Also interesting is that children whose mothers had been exposed to malaria messaging within 6 months before the study showed a heightened risk of contracting malaria compared to those whose mothers hadn’t received such information (P=0.1875 vs 0.1487). How good is the messaging if it increases occurrence of the illness?

Picture from kesontechs.com

I am still unemployed in my search for engineering work. So, I am considering how I could find gainful employment exploiting my status as Planet Earth’s leading expert on the null hypothesis that mosquitos do not spread malaria. Direct research on the topic does not seem probable because all malaria funding is from businesses trying to sell cures or preventions. I expect the real cures and prevention are improved nutrition, clean water and improved sanitation. There are already strong health incentives to improve these in developing countries and adding malaria prevention and cure may not strengthen the case much. And the political strength of the medical lobby could harm these programs if they start to see them as a threat to their malaria cash cow.

Let’s consider the major costs of the ‘war on malaria’ – poisoning people and poisoning the environment. Potentially harmful and ineffective vaccines, prophylactics and other medications are the biggest harm, but I can see no gainful employment opportunities in tackling this head on.

Protecting the environment from poisoning is a better option. Killing mosquitos remains a major obsession of malaria researchers, e.g. in today’s Malaria World ‘Early evening outdoor biting by malaria-infected Anopheles arabiensis vectors threatens malaria elimination efforts in Zanzibar’.

Spreading insecticides to kill mosquitos has costs and negligible benefits. Rachel Carson’s ‘Silent Spring’ ignited the environmental movement in 1962 by highlighting the damage the insecticide DDT was doing to the environment. Unbelievably DDT is still used in malaria control programs in Africa with approval of the so-called World Health Organization.

But even if the insecticide does not create additional collateral damage up the food chain, it’s very purpose of killing insects can have a serious deleterious effect on the ecological balance. Insecticides kill other insects beside mosquitos that may be beneficial. And what most people fail to realise is that mosquitos themselves are pollinating insects. They feed on nectar from flowers, the same as honey bees. Only breeding females require blood meals to get additional protein for their eggs. Male mosquitos never bite.

We hear so often about the threat to pollinators from pesticides. Is this ever considered when anti-mosquito campaigns are launched? Perhaps there are opportunities protecting these essential insects. I will explore further.

I welcome your thoughts.

A study in Malaria World this week ‘Assessment of malaria treatment interventions: a critical analysis of government initiatives and causes of treatment failure at Port Loko Government Hospital, Sierra Leone’ by Sao Babawo et al has useful information on important factors for malaria occurrence and the ineffectiveness of the conventional treatments.

Healthcare workers and women of childbearing age were surveyed. The study assessed the effectiveness of government interventions such as the distribution of insecticide treated bed nets, indoor spraying with insecticides, and availability of anti-malarial drugs (ACTs). These interventions failed and authors blamed failure on the implementation or inconsistent supply.

(Or perhaps nets, insecticides and artemisinin based drugs are ineffective because the conventional understanding of malaria is incorrect?)

The most interesting observations came from the surveys of healthcare workers and of the women of childbearing age. The women considered the most important factors for malaria occurrence to be poor environmental sanitation (33.7%) and sub-standard housing (11.0%). Not sleeping under a bed net (6.7%) and lack of access and availability of health services (5.0%) were considered less important.

What is also interesting is the health worker survey in which 73.3% reported that malaria was the most prevailing medical condition affecting pregnant women who attend a clinic. Also reported are Iron deficiency at just 13.3%, Pre-eclampsia 4.3%, Typhoid 8.3%, Others 0.7%.

It seems to me that malaria is the name given the illness in these clinics when a patient is generally unwell with generic symptoms. In a country free of malaria perhaps influenza, COVID or ‘viral illness’ would be the diagnosis. This fits with my recent experience in Kenya when my friend with chest and stomach pains and no fever was diagnosed with malaria and treated with artesunate because of a positive test. It is not even clear if all the women attending clinics in this Sierre Leone study were tested because stock outs of RTDs were also reported.