- Press Release Distribution

A lethal parasite’s secret weapon: Infecting non-immune cells

Finding defies textbook understanding of leishmaniasis infection

( COLUMBUS, Ohio – The organisms that cause visceral leishmaniasis, a potentially deadly version of the parasitic disease that most often affects the skin to cause disfiguring disease, appear to have a secret weapon, new research suggests: They can infect non-immune cells and persist in those uncommon environments.

Researchers found the Leishmania donovani parasites in blood-related stem cells in the bone marrow of chronically infected mice – precursor cells that can regenerate all types of cells in the blood-forming system. The finding may help explain why some people who develop visceral leishmaniasis, which is fatal if left untreated, often also have blood disorders such as anemia.

Identifying these cells and other unexpected locations in which these parasites live improves scientists’ understanding of the disease and may lead to new treatment options, said senior study author Abhay Satoskar, professor of pathology in The Ohio State University College of Medicine.

“Treating a patient with leishmania drugs never eliminates every parasite from the body – they persist for the rest of a patient’s life,” Satoskar said. “Perhaps these uncommon cells are the cells responsible for harboring these parasites in low numbers. Some drugs may not reach these cells properly or may not be effective with those parasites, and maybe the parasites in these kinds of cells are different compared to parasites in immune cells because they can adapt. It would be important to eliminate these hidden parasites if we want to stop the transmission of the disease.

“It changes the way we think about this parasite: If uncommon cells are infected, what is the cells’ role? What are the parasites doing there? How did they evade the drug treatment? Are they different from parasites in other cells, or the same? There are lots of questions.”

The research was published recently in the journal Cell Reports.

Cutaneous leishmaniasis is a disfiguring skin disease caused by Leishmania major parasites that affects up to 1.2 million people annually in the tropics, while L. donovani parasites cause the less common visceral leishmaniasis that attacks internal organs, affecting an estimated 100,000 people per year. Scientists have suspected L. donovani may stray beyond their immune cell hosts because they linger in the body, but those suspicions have been difficult to confirm with most conventional technologies because the number of infected cells is low.

Satoskar and colleagues used single-cell RNA sequencing in their search for parasites in spleen and bone marrow cells of chronically infected mice. The technique allowed the team to identify individual cell types based on the thousands of genes expressed by cells that function as a signature of each cell type. Simultaneously, the researchers identified which types of cells were – and were not – infected by L. donovani parasites based on the presence or lack of genes known to be expressed by these organisms.

In the spleen, most of the infected cells detected were frontline immune cells – macrophages and monocytes – known as phagocytes whose job is to swallow up invading organisms.

“Textbooks say Leishmania are parasites of immune cells, mainly phagocytes, that hijack those cells and live there. That is what we’ve learned for many years,” said Satoksar, also a professor of microbiology at Ohio State. “Though that was the dogma, it appears during chronic infection that they’re also infecting other cell types.”

The study showed that these infectious organisms weren’t restricted to only phagocytic cells in either organ – in bone marrow, the blood-related (hematopoietic) stem cells were the main parasitized cells, a surprising finding that was verified through a separate single-cell analysis. The fact their outer surfaces feature some of the same receptors as typical immune cell targets hints at why and how they harbor the parasites, Satoskar said.

Other types of cells in both organs whose gene expression signature suggested they contained L. donovani parasites included white blood cells that assist the immune system – but don’t engulf infectious organisms – and cells responsible for the production of platelets.

“Finding Leishmania genes linked to other cell signatures gives us clues of which cells to look for next in follow-up protocols,” Satoskar said.

This work has potential for rapid translation to human tissue testing in some tropical regions, where taking needle aspiration spleen and bone marrow samples is a routine procedure for people at risk for leishmaniasis. Such samples could be used to help determine if non-immune cells are occupied by parasites in humans as well.

“These are organs where these parasites persist for many, many years after an infection as cleared and a person who becomes immune suppressed can develop disease again,” Satoskar said. “With our animal data and what we find in human samples, we hope to understand the pathways that are assisting parasites to survive and use that knowledge to develop new therapies targeting those pathways.”

This work was funded by the Global Health Innovative Technology Fund and the National Institute of Allergy and Infectious Diseases.

Co-authors include Konstantinos Karagiannis, Sreenivas Gannavaram, Thalia Pacheco-Fernandez, Parna Bhattacharya and Hira Nakhasi of the Food and Drug Administration and Chaitenya Verma of Ohio State.




Contact: Abhay Satoskar,

Written by Emily Caldwell,; 614-292-8152




Ball milling provides high pressure benefits to battery materials

Cheaper, more efficient lithium-ion batteries could be produced by harnessing previously overlooked high pressures generated during the manufacturing process. Scientists at the University of Birmingham have discovered that routine ball milling can cause high pressure effects on battery materials in just a matter of minutes, providing a vital additional variable in the process of synthesizing battery materials. The research (part of the Faraday Institution funded CATMAT project), led by Dr Laura Driscoll, Dr Elizabeth Driscoll and Professor Peter Slater at the University of Birmingham is published in RSC Energy Environmental Science. The use ...

Congenital Heart Surgeons' Society (CHSS) and fourteen professional organizations announce recommendations for performing pediatric heart surgery in US

September 29, 2023, Cincinnati, OH — A set of recommendations to address the known variation in outcomes at US congenital heart surgery centers has been endorsed by 15 collaborating societies led by the Congenital Heart Surgeons' Society (CHSS). The guidelines will appear in “Recommendations for Centers Performing Pediatric Heart Surgery in the United States," to be co-published in the World Journal for Pediatric and Congenital Heart Surgery, Annals of Thoracic Surgery, and Journal of Thoracic and Cardiovascular Surgery. “In ...

Mouthwash for dogs: water additive with pomegranate helps to keep canine teeth healthy

Periodontal disease is one of the most common canine diseases, affecting at least 80% of dogs aged three and over. Periodontal disease begins as gingivitis, where gums become red and inflamed, and may bleed. Untreated, the disease can progress to periodontitis, where the alveolar bone is progressively damaged so that teeth may loosen or fall out. In turn, periodontitis is a risk factor for other diseases like cardiovascular and lung disease. A major cause of periodontal disease is poor oral hygiene, ...

Racial/ethnic minority patients may be less likely than white patients to receive palliative care during breast cancer treatment

ORLANDO, Fla. – Despite a steady increase in palliative care utilization from 2004 to 2020, non-Hispanic Black, Hispanic, and Asian or Pacific Islander patients with metastatic breast cancer were less likely to receive palliative care than non-Hispanic white patients, according to results presented at the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved, held September 29-October 2, 2023. Palliative care consists of treatments or procedures intended ...

Spanish-speaking men in sexual minority groups may lack knowledge about cancers linked to HPV

ORLANDO, Fla. – A study found multiple gaps in awareness and knowledge about the connection between the human papillomavirus (HPV) and several types of cancer among Hispanic and Latino men who identified as sexual minorities, according to results presented at the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved, held September 29-October 2, 2023. “Sexual minority men are a population group at higher risk for HPV infections and ...

Structural racism may play a role in increased cancer mortality rates among racial minorities

ORLANDO, Fla. – Structural racism was associated with increased county-level cancer mortality rates among minority populations compared with whites, according to results presented at the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved, held September 29-October 2, 2023. “Applying measures that attempt to capture the multiple and compounding ways racism presents in policies, laws, and practices at a population level shows how racism manifests beyond interpersonal interactions to negatively impact cancer outcomes,” said presenter Joelle N. Robinson-Oghogho, ...

Racial and ethnic minorities may be less willing than others to participate in clinical trials

ORLANDO, Fla. – A survey conducted in one cancer center’s catchment area found that while a majority of respondents would be willing to participate in a clinical trial, members of racial and ethnic minority groups were significantly less likely to participate than non-Hispanic whites, according to results presented at the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved, held September 29-October 2, 2023. Reasons to participate ...

NCI-sponsored cancer clinical trials have become more diverse over past two decades

ORLANDO, Fla. – Compared to the year 2000, a greater proportion of NCI-sponsored early-phase clinical trial participants in 2022 were older, from minority racial/ethnic groups, and lived in historically underrepresented regions of the U.S., according to a study presented at the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved, held September 29-October 2, 2023. “Early-phase clinical trials, which primarily evaluate the safety of new therapies, have historically had insufficient representation of racial minorities, women, elderly ...

Research finds DEI initiatives during certain presidencies can affect bottom line

DURHAM, N.H. — Corporate initiatives focused on diversity, equity and inclusion (DEI) for vulnerable social groups can change a company in many ways. According to researchers at the University of New Hampshire, how DEI affects a business’ bottom line may depend on the presidential administration and the general public’s perception at the time. They found that DEI initiatives put in place to support a specific social group during a presidential administration perceived as unfriendly to a particular issue related to that community resulted in higher stock prices than during a presidency that had a better relationship ...

Alcohol 'promotion' detracted from success of Women's World Cup

Broadcasters should avoid focusing on alcohol in crowd shots during major sporting events, such as this summer’s Women’s World Cup final, say researchers. In a new commentary published in the Journal of the Royal Society of Medicine (JRSM), researchers from the Technological University of the Shannon and the University of Galway in the Republic of Ireland suggest that the ‘thorny issue of alcohol’ detracted from the success of the record-breaking tournament. The authors, Dr Frank Houghton ...


4D Medicine raises £3.4 million for unique biomaterial platform

Ancient marine animal had inventive past despite being represented by few species, new study finds

Quantum sensor for the atomic world developed through international scientific collaboration

The research was wrong: study shows moderate drinking won’t lengthen your life

Save your data on printable magnetic devices? New laser technique’s twist might make this reality

Early onset dementia more common than previously reported – the incidence of Alzheimer’s disease seems to be on the rise

Pesticides potentially as bad as smoking for increased risk in certain cancers

NUS researchers develop new battery-free technology to power electronic devices using ambient radiofrequency signals

New protein discovery may influence future cancer treatment

Timing matters: Scripps Research study shows ways to improve health alerts

New gene therapy approach shows promise for Duchenne muscular dystrophy

Chemical analyses find hidden elements from renaissance astronomer Tycho Brahe’s alchemy laboratory

Pacific Northwest launches clean hydrogen energy hub

Tiny deletion in heart muscle protein briefly affects embryonic ventricles but has long-term effects on adult atrial fibrillation

Harms of prescribing NSAIDs to high risk groups estimated to cost NHS £31m over 10 years

Wearing a face mask in public spaces cuts risk of common respiratory symptoms, suggests Norway study

Some private biobanks overinflating the value of umbilical cord blood banking in marketing to expectant parents

New research in fatty liver disease aims to help with early intervention

Genetics reveal ancient trade routes and path to domestication of the Four Corners potato

SNIS 2024: New study shows critical improvements in treating rare eye cancer in children

Wearable devices can increase health anxiety. Could they adversely affect health?

Addressing wounds of war

Rice researchers develop innovative battery recycling method

It’s got praying mantis eyes

Stroke recovery: It’s in the genes

Foam fluidics showcase Rice lab’s creative approach to circuit design

Montana State scientists publish evidence for new groups of methane-producing organisms

Daily rhythms depend on receptor density in biological clock

New England Journal of Medicine publishes outcomes from practice-changing E1910 trial for patients with BCR::ABL1-negative B-cell precursor acute lymphoblastic leukemia

Older adults want to cut back on medication, but study shows need for caution

[] A lethal parasite’s secret weapon: Infecting non-immune cells
Finding defies textbook understanding of leishmaniasis infection