A new study has revealed that school-age children with no symptoms of malaria could serve as super-spreaders of the disease.
Malaria is globally acclaimed as the largest killer of children, with one child dying from it every 30 seconds, and about 3,000 every day,
The researchers said findings from the study revealed a hidden reservoir that could be a barrier to long-term efforts to eliminate malaria and an immediate threat for the resurgence of the disease despite long-serving control measures.
They also noted that the findings are important because it would help those planning malaria control and prevention to understand those that are capable of transmitting the disease, especially in areas where there have been success stories.
Findings from the study, which was conducted in Uganda, were reported at the virtual annual meeting of the American Society of Tropical Medicine and Hygiene.
According to the World Health Organisation, malaria, a mosquito-borne infectious disease, is responsible for the deaths of more than 400,000 people in 2019.
The WHO noted that nearly half of the world’s population is at risk of contracting it. It pointed out that in areas with high malaria transmission, young children and pregnant women are most vulnerable to catching the infection, and – in worst-case scenarios – dying from it.
It revealed that 90 per cent of cases are reported to be in sub-Saharan Africa – with children under five accounting for 65 per cent of all deaths.
A Public Health Practitioner and Sustainable Development Consultant, Dr. Laz Eze, said malaria is a potential medical emergency and should be treated accordingly.
He noted that delays in diagnosis and treatment are leading causes of death in many countries, adding that prompt and accurate diagnosis is critical for effective management of malaria.
Dr. Eze, however, maintained that there is a standard diagnosis for detecting malaria in people, including children.
According to a co-author of the study and Professor of Epidemiology of Tropical Infectious Diseases, Teun Bousema, It is important to understand who transmits malaria, adding that this is particularly important in areas where malaria control is successful.
Bousema, who specialised in the Biology and Epidemiology of Plasmodium falciparum at Radboud University Medical Center in the Netherlands, in an article published on SciDev.Net, said those running control programmes need to know whether malaria may come back and who in the human community can cause mosquito infections.
This, she noted, will help to determine when disease control can become less rigorous or when resurgence is very unlikely.
Another author and a doctoral student, Chiara Andolina, said in some ways, the study is a blueprint of what can be expected in other countries where mosquito control is very successful.
“Malaria will not disappear completely. It will persist in some populations,” she added.
“We now have the first direct evidence that even in places under very intensive malaria control, a small number of asymptomatic super spreaders can quietly sustain transmission — and finding and treating them could prove very challenging.”
In carrying out the study, the researchers disclosed that they assessed the transmission of malaria among children showing symptoms of malaria and those who did not present symptoms in Tororo district, eastern Uganda.
The area, they noted, has been targeted with malaria control measures, including regular distribution of insecticide-treated nets, indoor residual spraying with insecticides and access to effective malaria drugs.
They conducted regular tests for evidence of malaria parasites on 531 people, including children aged five to 15 years old for 24-month.
According to the findings presented at the meeting, a school-age child who showed no symptoms despite harbouring seven different variations of the malaria parasite Plasmodium falciparum “was responsible for 24.7 per cent of all infected mosquitoes infections observed”.
“In this unique longitudinal study, we find that asymptomatic infections [with no symptoms] in school-age children are responsible for the majority of onward transmission events,” they added.
Shedding more light on this, Bousema said, “They are very prone to infection and keep their infections longer because they have some level of immunity that prevents symptoms but not an infection.”
“Malaria-free school initiatives can have an important impact, not only for school children but, as we show, also for the wider community since they are important transmitters of the infection.”
Andolina, on her part, said such children can be easily targeted with interventions such as medicines that can prevent them from acquiring parasites at all as they are easily accessible in their schools.
A Paediatric Infectious Disease Specialist at the University of Maryland School of Medicine, United States, Lauren Cohee said the findings offer insights into malaria control.
“The extent to which transmission may be driven by a small number of highly infectious individuals is surprising and may open a new chapter for malaria control,” she added.
Cohee, however, said the yardstick used to measure malaria control interventions has traditionally been how many lives are saved or how many deaths are averted.
“While this is clearly an essential metric, policymakers should consider the impact of control interventions on transmission,” she advised.
According to the Centers for Disease Control and Prevention, only Anopheles mosquitoes can transmit malaria and they must have been infected through a previous blood meal taken from an infected person.
“When a mosquito bites an infected person, a small amount of blood is taken in which contains microscopic malaria parasites.
“About one week later, when the mosquito takes its next blood meal, these parasites mix with the mosquito’s saliva and are injected into the person being bitten,” it explained.
According to Medical Xpress, malaria parasites are dependent on a life cycle in which they constantly move back and forth between humans and mosquitoes.
“Successfully interrupting transmission of the disease includes clearing parasites from human hosts, which can be accomplished with anti-malaria drugs.
“There is currently concern that the fight is stalling and that a variety of factors—including declining budgets for malaria control and rising insecticide and drug resistance—could allow the disease to stage a come-back,” it stated.
Speaking exclusively with PUNCH Healthwise, Dr. Eze said the globally accepted standard to determine if an individual has the disease is through diagnosis.
He explained that malaria can be diagnosed by examining under the microscope a drop of a patient’s blood, spread out as a blood smear on a microscope slide.
“That is the gold standard method of diagnosing malaria,” he added.
“Of course, there is also the Rapid Diagnostic Test, which is an alternate way of quickly establishing the diagnosis of malaria infection by detecting specific malaria antigens in a person’s blood.
“But that one is not the gold standard. Anything short of these two diagnostic methods is a mere assumption.
Speaking on accepted methods of treating malaria in children or adults, he said it is not advisable to treat for malaria without a diagnosis, adding, “Without a confirmatory test, there is no malaria.
“Whoever is treating is just doing a presumptive treatment. It is either there is malaria or it is missing.
“I can’t treat malaria without a test. In most cases, there is a history of fever with a temperature of above 37.5 degree Celsius.
“And in some cases when there is high fever, drugs are taken to calm it down, but tests must be done to show the presence of malaria parasites.
“In the absence of that, people are doing a presumptive treatment, which is absolutely not recommended.”
The medical practitioner said the symptoms people have for malaria is not exclusive to malaria, noting that they could be similar symptoms for other diseases.
“If there is a high temperature, there are over a thousand things that can give a high temperature.
“People have sores on the mouth and feel it is malaria. It is simply herpes virus that does that,” he said.
Dr. Ezeh said when it comes to malaria prevention, pregnant women who are more at risk and are given Intermittent Preventive Treatment in pregnancy (IPTp).
The physician said the best preventive measure against malaria is to eliminate the environment that makes mosquitoes to thrive.
He said, “Things that would cause mosquito infestation should be taken care of.
“If mosquitoes are eradicated, inadvertently, the parasite would be kicked out.
“The recommended prevention methods include sleeping inside long-lasting insecticide-treated mosquito nets, use of insecticides, care for the environment and getting rid of artificial still water collections around homes.”
All rights reserved. This material, and other digital content on this website, may not be reproduced, published, broadcast, rewritten or redistributed in whole or in part without prior express written permission from PUNCH.
The post Asymptomatic children could be ‘super-spreaders’ of malaria –Study appeared first on Healthwise.