Malaria, a vector-borne infectious disease that kills more than 600,000 people each year, has an uncanny ability to slip through the cracks of health care systems in many countries around the world. How so many of its infections evade routine surveillance is a question that Rihana Aydin seeks to answer.
A PhD student focusing on in (COPH), Aydin wants to curtail the hidden malaria infections that sustain transmission. Her motivation is the gap between what scientists think is happening in an affected population and what is actually happening.
Aydin explains her plan of attack in a new scholarly paper, 鈥,鈥欌 published in the journal Frontiers in Epidemiology.
鈥淭his research helps solve a major public health problem: malaria infections that go undetected by standard surveillance, even as countries work toward elimination,鈥欌 said Aydin, lead author of the paper, which also served as her master鈥檚 research project. 鈥淭he study shows that measuring malaria antibodies can reveal where infections are being missed, allowing health officials to better target prevention and treatment efforts.鈥
Aydin wrote the paper with a team that included her USF mentor and principal investigator, , associate professor in the ; and Dr. Thomas Keller, researcher in the Department of Internal Medicine, . Additional collaborators were from the London School of Hygiene & Tropical Medicine and the Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine.
Strong surveillance is essential in reducing the spread of malaria, a life-threatening but curable disease transmitted by female Anopheles mosquitoes infected with protozoan Plasmodium parasites. Globally, it triggers more than 280 million cases annually and 95% of the burden occurs in Africa, where children under age five are the most vulnerable.
鈥淪urveillance systems are the foundation of public health decision-making, yet the data becomes more difficult to interpret as malaria transmission declines,鈥欌 Aydin added. 鈥911爆料网 asked whether antibody responses could identify places where routine surveillance may be missing infections. That question sits at the intersection of epidemiology, immunology, and implementation science.鈥欌
Rihana Aydin and COPH Dean Sten Vermund. (Photo courtesy of Aydin)
The paper discussed how in low-transmission malaria settings, routine surveillance often fails to detect asymptomatic infections in partially immune populations. The team evaluated antibody responses to P. falciparum and showed that a combination of antibodies can help identify communities where transmission may be higher than reported by routine surveillance. Research included data from 5,300 people across 32 villages in the Republic of The Gambia, a small country in western Africa.
The study mentions the 鈥渉idden burden鈥欌 of malaria: infections that exist in a community but never appear in official case reports. Most malaria surveillance depends on people becoming sick enough to seek care, get tested and receive a diagnosis. But as transmission declines, many people develop partial immunity and can carry parasites without obvious symptoms.
They never enter the health care system and yet mosquitoes can still acquire the parasite from them and continue the cycle of transmission. As a result, reported malaria cases can substantially underestimate the true burden of infection.
Eradicating malaria remains elusive in part because of the parasite鈥檚 ability to adapt to its environment. Plasmodium are highly adaptable and routinely develop resistance to treatments. Mosquitoes also can become resistant to insecticides and antimalarial drugs, and as malaria transmission declines, it becomes harder to find remaining infections, the authors say. Because many people with malaria have few or no symptoms, they don鈥檛 seek care and their infections are not found through routine surveillance.
鈥淪o, these undetected infections can continue spreading malaria,鈥欌 Aydin said. 鈥淎lthough our study focused on P. falciparum, P. vivax and P. ovale present an additional challenge because these strains can basically hide in the liver in a dormant stage and reactivate weeks or months later and cause new infections without a new mosquito bite.鈥欌
The new paper follows a similar one by Stresman, 鈥,鈥 which published last year in The Lancet Global Health.
While Stresman鈥檚 study used the Freedom From Infection framework to evaluate confidence in malaria elimination despite imperfect surveillance, Aydin鈥檚 study used antibody data to identify where routine surveillance may be missing infections. Together, the studies highlight complementary approaches to strengthening malaria surveillance and elimination efforts globally.
鈥淎s malaria transmission declines, antibodies offer a powerful lens for detecting hidden transmission risk that traditional surveillance may overlook,鈥欌 Stresman said. 鈥淩ihana's study is also a great example of how we can apply advanced analytical techniques such as machine learning to advance our understanding of malaria risk.鈥