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Category: CTEGD Blog

Fagbami named 2022 Burroughs Wellcome Fund PDEP Fellow

Donna Huber on July 13, 2022

postdoctoral fellow Lola Fagbami
UGA’s Lọla Fagbami, winner of a Burroughs Wellcome Fund 2022 Postdoctoral Diversity Enrichment Program fellowship, is a native of Lagos, Nigeria, who relocated to the United States with her family in the late 1990s. She is passionate about expanding scientific literacy through outreach and mentoring as well as refuting chemophobia—the fear of or aversion to chemicals and chemistry. (Photo by Lauren Corcino)

Lọla Fagbami, a postdoctoral research associate at UGA, has been awarded a Burroughs Wellcome Fund 2022 Postdoctoral Diversity Enrichment Program fellowship.

Fagbami, UGA’s first PDEP Fellow, conducts research on the human malaria parasite Plasmodium falciparum at the Center for Tropical and Emerging Global Diseases. She works with Vasant Muralidharan, associate professor of cellular biology in the Franklin College of Arts and Sciences, who nominated her for the award.

“Dr. Fagbami has excellent training in metabolomics, mass spectrometry and Plasmodium drug discovery. Her exceptional work as a graduate student has shown how human malaria-causing parasites use metabolic adaptation to induce antimalarial drug resistance. Dr. Fagbami is a fearless, highly intelligent, accomplished and outstanding scientist who will be a leader in our field,” Muralidharan wrote in his nomination letter.

“Her research project addresses a major gap in the field that has enormous implications for malaria elimination and eradication efforts,” he added.

The PDEP award provides $60,000 over three years to support career-development activities for historically excluded minority postdoctoral fellows pursuing academic careers in biomedical or medical research, according to the Burroughs Wellcome Fund.

“This award is an investment in me as a scientist and leader and will help advance my career to the next level,” Fagbami said. “I am excited to join the extraordinary community of PDEP scholars and also connect with program alumni who have successfully made the transition to research independence.”

Fagbami earned a B.S. in chemistry at Emory University, an M.B.S. and an M.P.H. in health policy at Rutgers University, and a Ph.D. in chemical biology at Harvard University.

Increasing the knowledge base on brain-eating amoeba

Donna Huber on April 28, 2022

graduate student Cassie Russell in front of biological safety cabinet in Dennis Kyle's laboratory at the University of Georgia
Cassie Russell, a graduate student in the Department of Infectious Diseases, in her laboratory space. (Photo by Ian Bennett)

Cassie Russell, a graduate student in the Department of Infectious Diseases, was an undergraduate when she first heard of Naegleria fowleri, also known as the brain-eating amoeba. While whole lectures in her parasitology course had been dedicated to other parasites, N. fowleri was barely a mention.

“I remember maybe 15 minutes was spent on it,” said Russell. “I was shocked that was all that was known about this deadly organism.”

N. fowleri causes the acute neurological disease primary amoebic meningoencephalitis (PAM). There have been hundreds of reported cases of PAM, but only seven survivors worldwide, according to the Centers for Disease Control and Prevention.

SEM image of Naegleria fowleri
Scanning electron microscopy image of Naegleria fowleri (submitted by Cassie Russell)

“I had the opportunity to speak with families in Florida who had lost someone to Naegleria fowleri infection,” she said. “The fear they had in not knowing what was wrong with their loved one and then learning that there was very little that could be done—their stories were just heartbreaking.”After arriving at UGA, Russell was pleased to find out that N. fowleri was one of the parasites being studied in Dennis Kyle’s laboratory at the Center for Tropical and Emerging Global Diseases.

Individuals, most commonly young children, become infected when they inhale warm freshwater contaminated with N. fowleri. This typically occurs during the late summer months when people are participating in recreational activities in rivers and lakes, but it can also occur when people use unsterilized tap water in nasal irrigation devices. It is more likely to occur in the southern United States, but infection is very rare. Between 2011 and 2020 only 33 cases were reported in the United States, according the CDC.

N. fowleri is one of the most neglected of the neglected tropical diseases. However, knowledge about the parasite has been growing since the 1960s as scientists build on new data and apply new technology. Russell is doing her part and was the lead on a study recently published in Microbiology Spectrum where, for the first time, drug susceptibility was tested across 11 clinical isolates.

“Current drug treatment is a cocktail of six different drugs,” said Russell. “However, only a few isolates have been tested in the lab for susceptibility. We don’t know if some drugs work better for different strains.”

A big question facing researchers is why these drugs show effectiveness in the lab when so few real-world cases have been successfully treated. Russell suspected that other factors were at play in treatment failure, such as genetic differences among geographically distinct amoeba populations.

The 11 isolates used in the study came from patients who contracted N. fowleri in different geographic regions. Russell found that these isolates had significant differences in susceptibility to seven of the eight drugs currently used to treat the infection.

The need for effective and fast-acting treatments is especially great. PAM is almost always fatal, with death occurring about a week after the initial onset of symptoms.

Doctors are racing against the clock as there is often a delay in diagnosis: The symptoms mimic meningitis, and N. fowleri is a rare infection. The drugs used can also be pretty toxic, so identifying the safest and most effective drug treatment could significantly improve outcomes.

Russell’s findings are another stepping stone to propel N. fowleri research toward increased understanding of this parasite and ultimately better treatments. For example, she realized that there is not a gold standard for genotyping.

“Researchers could be talking about genetically different isolates but not realize it,” said Russell.

In addition to creating a genotyping standard, she has identified combinational drug studies to test for synergism as a next step. For now, though, Russell is focusing on another need in the fight against N. fowleri—diagnostics.

“Awareness, improved diagnostic techniques and faster-acting drugs are needed to improve outcomes,” she said.

 

This story first appeared at https://research.uga.edu/news/increasing-the-knowledge-base-on-brain-eating-amoeba/

Creating databases to help cure diseases worldwide

Donna Huber on March 31, 2022

by Jill Neimark
Jessica Kissinger poses for a photo in the Infectious Diseases Institute in Uganda where she is currently a US Fullbright Scholar. (Photo/Courtesy Jessica Kissinger)

Jessica Kissinger is using her expertise in biology and big data to help other scientists

 

Jessica Kissinger never set out to make databases. From the time she was a little girl, she wanted to be a biologist.

Today, the University of Georgia professor not only studies deadly pathogens like malaria and Cryptosporidium (a waterborne parasite), but also is a driving force behind worldwide, groundbreaking collaborations on novel databases. During her time at UGA, she has received nearly $40 million in federal and private grants and contracts.

These databases can crunch vast amounts of biological information at warpspeed and reveal important patterns that pave the way for new approaches to scourges such as Leishmania (common in the tropics, subtropics, and southern Europe), toxoplasmosis (a systemic disease due to one of the world’s most common parasites), and Valley Fever (a fungus born on the wind that can cause lung and systemic infections). Novel drug and vaccine targets can be developed, as well as fresh insights on life-threatening pathogens.

“Fighting infections and developing new drug and vaccine targets requires detailed knowledge of a pathogen and how it functions,” explained Kissinger, a Distinguished Research Professor in UGA’s Department of Genetics, Institute of Bioinformatics and Center for Tropical and Emerging Global Diseases.

And, like internet searches, the databases are all free. Kissinger said it’s likely that pharmaceutical companies are mining some of the information in their quest to discover new therapeutic targets.

“They don’t tell us what they’re working on,” she said. “A database itself doesn’t produce a cure. A database can, however, remove most barriers to analysis of existing data.”

Big Data paves the way for big advances in science

It once took an entire decade to sequence a single genome—and the cost was many millions. Today, researchers can sequence a genome in a single afternoon for a few thousand dollars, transforming the field of genomics. Similar astounding advances have reshaped other ‘omics’ specialties, such as proteomics (study of proteins), metabolomics (study of metabolism), transcriptomics (study of RNA), and epigenomics (the influence of the environment on gene function). These advances mark the “Big Data” era in biology.

“The power that is unleashed by big data is phenomenal,” said Kissinger, “and it’s a very exciting time in history, with major funders and visionaries all across the world forming consortia to create a kind of ideal data universe.” Like explorers trekking into a new world, they will make discoveries we might only imagine right now.

Creating a malaria database

Kissinger’s innovations began over 23 years ago, while she was a postdoctoral researcher at the University of Pennsylvania studying a single-celled parasite called Toxoplasma gondii. The parasite shares some important features with the malaria pathogen, whose genome was in the process of being sequenced.

“I rounded up genome data from all over the world on Plasmodium (the causative agent of malaria), and ran analyses and put it on a website, so I could study the genes it might share with Toxoplasma,” she recalled. “It turns out nobody had made the Plasmodium data available for searching before.”

Soon she and her adviser, David Roos, had a million-dollar grant to formally establish a malaria database, PlasmoDB, and since its launch in 1999 it has grown to include additional pathogens and received continual funding from the NIH, the most recent for up to $38.4 million to maintain what has now become the Eukaryotic Pathogen, Vector and Host Informatics Resources knowledgebase (VEuPathDB), covering 14 different pathogens as well as host responses to infections. This comprehensive database is an integrated centralized resource for data mining on over 500 organisms.

The databases collectively contain over nine terabytes (9,000 gigabytes) of data, and have been compared to a Wikipedia for molecular parasitology by the British Society for Parasitology, which noted back in 2006: “We don’t know what we would do without it!”

Each month, VEuPathDB receives over 11 million hits from an average of 36,000 unique visitors in more than 100 countries, including India, Brazil and Kenya. A related database on vectors of disease (such as ticks that carry Lyme disease) was recently merged into VEuPathDB. The merger expanded each resource and enables researchers to better explore data on vectors such as ticks and mosquitoes and the pathogens they transmit.

Powerful tools are key to analyzing data

The databases are not just strings of numbers or words. They allow visualizations and graphic interfaces. Already, research is emerging that can help direct vaccine and drug development away from proteins that hosts and pathogens share, in order to protect the cell. Scientists using the databases have discovered proteins that reduce severe malaria and other proteins that protect malaria parasites from the human fever response. They have also found proteins that help Toxoplasma penetrate host cells.

In a single year an average of 200 publications a month cite VEuPathDB, and to date there have already been 24,000 citations total. Next up: cloud-ready applications and improved integration with yet other databases. These databases “have become essential data mining and access platforms for fungal and parasite genomics research,” said microbiologist and plant pathologist Jason Stajich of the University of California at Riverside.

“Without powerful, user-friendly tools to analyze it, “Big Data” is more a curse than a blessing,” explained John Boothroyd, an immunologist and microbiologist at Stanford University School of Medicine. “VEuPathDB is just such a tool and we owe Jessica Kissinger and her colleagues an enormous thank you for their tireless and selfless efforts to first conceive and then continuously improve this absolutely essential resource.”

Grants for related projects have come from a wide array of organizations, among them the Bill & Melinda Gates Foundation, the Sloan Foundation, and the World Health Organization. One of those projects, called ClinEpiDB, is home to a multicenter study that contains data from over 22,000 children from seven different sites in South Asia and Africa. This study is the largest ever to investigate the causes of diarrhea in children in lower- to middle-income countries. Other uses of ClinEpiDB include new data on hidden signs of malaria transmission in areas where incidence is declining, or how breastfeeding protects infants from common infections.

The VEuPathDB database would be enough to secure Kissinger’s reputation in the biological sciences, but she has not stopped there. At the University of Georgia, she was a founding member of the Institute of Bioinformatics, and served as its director from 2011 to 2109. The Institute’s mission is to facilitate cutting-edge interdisciplinary research in computational biology, and the program offers both masters and doctorates. She is a key researcher helping to partner a national hub for infectious disease research by linking with Emory University in Atlanta. The two institutions have grants totaling over $45 million to work on everything from tuberculosis to HIV to malaria.

“These databases are a success beyond my wildest dreams,” said Kissinger. “They are made by biologists for other biologists and address a real-life need.”

 

This story first appeared at UGA Today.

Trainee Spotlight: Justine Shiau

Donna Huber on February 9, 2022

Justine Shiau

Justine Shiau, an NIH T32 fellow in Dr. Dennis Kyle’s laboratory, is originally from Taipei, Taiwan, and moved to the states after elementary school. She received her bachelor’s degree in Biology from the Pennsylvania State University, where she became interested in disease transmission, disease ecology, and parasitology while working with Dr. Ashutosh Pathak. Upon graduation, she moved to Athens to continue her training with Dr. Pathak, who at that time was working in the transmission ecology of vector-borne diseases with Dr. Courtney Murdock. Over the next two years, she took part in research projects revolving around vector biology and mosquito-transmitted pathogens. She was accepted by the UGA Integrated Life Science graduate program in Fall 2018.

In the Kyle lab, Justine is currently working on the transmission stages of Plasmodium falciparum, a human malaria parasite that causes significant mortality worldwide, specifically on the biology of the parasite transitioning from the vector to the human and the early stages within the human, prior to disease onset. She aims to complete the parasite’s life cycle in a laboratory setting, which would be a powerful tool to help further our understanding of the host-parasite interactions. She hopes to better understand the parasite biology and the transmission dynamic that the mosquitoes could have on the downstream infection in humans, which can potentially help us better understand and combat this horrible disease.

Why did you choose UGA?

UGA has one of the finest insectary facilities that allows the transmission of Plasmodium falciparum. Additionally, the Center of Tropical and Emerging Global Diseases (CTEGD) is the hub for parasitologists. The Center provides state-of-the-art infrastructure, research equipment, and, most of all, a supportive environment to cultivate and train graduate students to meet our goals.

What is your research focus?

Plasmodium falciparum is a parasite that causes malaria, which 50% of the world’s population is at risk of getting. Many children die from malaria every year; we cannot effectively prevent diseases and transmissions without a well-rounded understanding of the parasite’s biology and the essential players (mosquitoes) to complete its life cycle. My overarching goal is to complete the parasite’s life cycle in the lab. Currently, we are focusing on the biology of the parasite and its transition from mosquito back to human and within the human: from liver-to-blood stage infections. While doing this, there are two primary objectives that I would like to meet. First, I want to better understand the important factors for the parasites to establish infection in the human liver cells. Second, I am curious whether the mosquito stage infection can also impact the parasite’s efficiency in establishing infection in the human liver.

What are your future professional plans?

After graduate school, I hope to continue my postdoctoral training. I would like to pursue interdisciplinary research, with crosstalk between disease-ecology, parasitology, and vector biology.

Any advice for a student interested in this field?

Be open-minded and respectful to people with different expertise and people with diverse backgrounds.

 

Support trainees like Justine by giving today to the Center for Tropical & Emerging Global Diseases.

Jessica Kissinger elected as AAAS Fellow

Donna Huber on January 27, 2022

Jessica Kissinger with student
Dr. Jessica Kissinger with student

Three University of Georgia faculty have been named Fellows of the American Association for the Advancement of Science.

In a tradition stretching back to 1874, these individuals are elected annually by the AAAS Council for their extraordinary achievements leading to the advancement of science. Fellows must have been AAAS members for at least four years.

“Researchers are elected Fellows of the AAAS by their peers in recognition of significant contributions to their field,” said Karen Burg, vice president for research. “As we expand our research and innovation ecosystem, it’s exciting to see our faculty continue to be honored for their superb scholarship. I congratulate all of them on this wonderful achievement.”

The 2021 class of AAAS Fellows includes 564 scientists, engineers and innovators spanning 24 scientific disciplines who are being recognized for their scientifically and socially distinguished achievements. The new Fellows will be honored at the annual AAAS meeting in Philadelphia, Feb. 17-20.  Along with the rest of their 2021 class, UGA’s three new Fellows will receive an official certificate and a gold and blue rosette pin whose colors represent science and engineering.

Including these three, 37 faculty at UGA are Fellows of the American Association for the Advancement of Science.

UGA’s 2021 AAAS Fellows are:

James E. Byers: Meigs Distinguished Teaching Professor and associate dean for research and operations in the Odum School of Ecology, Byers was selected for distinguished contributions to the field of ecology, particularly in invasion biology, parasite ecology, ecosystem engineering and range boundaries in marine environments, as well as excellence in teaching.

Jessica Kissinger: Distinguished Research Professor of genetics in the Franklin College of Arts and Sciences and a member of the Center for Tropical and Emerging Global Diseases, Kissinger was selected for distinguished contributions to the field of the evolution of infectious diseases, particularly for bioinformatics approaches.

Patricia Yager: Professor of marine science in the Franklin College, Yager was selected for outstanding work on climate-driven processes and their impact on marine ecosystems.

To view a list of all AAAS Fellows from UGA, visit the Office of Research website.

 

The story by Ian Bennet first appeared on UGA Today.

Cytometry Shared Resource Lab expands capabilities with new instrument

Donna Huber on January 20, 2022

Julie Nelson
Julie Nelson, CSRL manager, is available to train users on the newly acquire CYTEK Aurora flow cytometer. (photo credit: Donna Huber)

With the generous financial support of The Office of Research, Cytometry Shared Resource Lab, Center for Tropical and Emerging Global Diseases, Department of Infectious Diseases, and UGA faculty members Rick Tarleton, Mark Tompkins, Chet Joyner, and Sam Kurup, the CTEGD Cytometry Shared Resource Laboratory (CSRL) recently added the Cytek Aurora Spectral Cytometer to its facility. This new instrument provides a high level of flexibility to the researcher and complements the other instruments available at the facility.

“It’s great to be able to bring this exciting new resource to campus in support of the incredible research UGA members are conducting,” said Julie Nelson, CSRL manager.

Flow cytometry is a technique for measuring characteristics of cells or particles using laser excitation and innate fluorescence emission or emission from dyes added to identify cells or particles and their function in experimental biology.  In the past 30 years, this technology has revolutionized many areas of cell biology research including the study of viruses, bacteria, infectious diseases, and cancer.  This technology has also proven useful in genetic studies of plants.

The Aurora Spectral Cytometer delivers high-resolution data at the single-cell level to resolve the most challenging cell populations, such as cells with high autofluorescence or low levels of expression of key biomarkers, regardless of assay complexity. With 64 emission detectors and 5 lasers for excitation, the Aurora can resolve almost any fluorescent marker currently on the market. It can also evaluate dyes under development that can be excited by one or more of the 5 lasers available.

“This cytometer expands our capabilities from a limit of 24 parameters to 64 making it ideal for high dimensional immunophenotyping,” said Nelson. “But because of its unique spectral emission detection, it is also the best instrument for looking at highly autofluorescent cells, such as macrophages and liver cells, regardless of how many markers are needed for the assay.”

For more than 20 years, the CSRL has provided access to state-of-the-art flow cytometry analyzers to researchers at the University of Georgia and across the scientific community. In addition to the instruments, the facility also provides expert advice and consultation for the design and analysis of flow experiments.

The CSRL is hosting a free webinar on the CYTEK Aurora on Friday, January 28 at 1:00 pm with Christopher Fleming, Ph.D. To register: https://register.gotowebinar.com/register/2294357931236562192

webinar flyer

Trainee Spotlight: Benjamin Phipps

Donna Huber on November 16, 2021

Benjamin Phipps

Benjamin Phipps is an NIH T32 trainee in Michael Strand‘s laboratory. Originally from Woodland, California, Benjamin earned his bachelor’s degrees in Spanish and biology and a minor in chemistry from the University of North Texas in May 2019. While at UNT, he studied the influence of mixed vehicle emissions on regulation of the renin-angiotensin system with Dr. Amie Lund and programmed translational frameshifts in Streptomyces bacteriophages with Dr. Lee Hughes. Benjamin earned research support and two travel grants to report his findings for his undergraduate projects. In August 2019, he enrolled in the Integrated Life Sciences (ILS) program at UGA and completed several laboratory rotations in parasitology before joining the Strand Research Group. He has served as treasurer of the Genetics Graduate Student Association and currently serves in that role for the CTEGD GSA.

Why did you choose UGA?

I chose UGA for its strong track record in research and breadth of research topics. I enrolled at UGA through Integrated Life Sciences, a gateway Ph.D. program that allows incoming students to explore several life sciences departments before choosing one for their dissertation home. This allowed me to experience a greater range of research topics than if I had enrolled directly in a single department. I also developed an interest in parasitology in the last year of my undergraduate program and therefore was drawn to CTEGD, one of the largest and most active centers for parasitology research in the world.

What is your research focus/project and why are you interested in the topic?

Many mosquito species must feed on vertebrate blood to produce eggs, and thereby can transmit several blood-borne pathogens of humans. Malaria is by far the deadliest of these, killing hundreds of thousands of people each year. Suppressing mosquito populations is an attractive approach to curbing transmission of malaria. Two promising targets for limiting mosquito reproductive capacity are the communities of microorganisms that reside in the mosquito gut, which are thought to influence fecundity by aiding blood digestion, and hormones mobilized in response to the blood meal that regulate egg formation. Malaria parasites have an antagonistic relationship with mosquito gut microbes and exploit resources generated for egg production after the blood meal. My dissertation project focuses on how mosquito gut microbes influence malaria infection by modulating reproductive signaling. This research has the potential to identify microbial species that might be exploited for malaria control, as well as elucidate important functions of gut microbes in preventing infections in animals.

What are your future professional plans?

I am presently most interested in a career in academia because I enjoy mentorship and science writing, but I remain open to other opportunities.

What do you hope to do for your capstone experience? 

For my capstone experience, I would like to draw on my training in both parasitology and Spanish language to travel to Colombia or Venezuela, where malaria is declining but still endemic. Potential activities there would involve characterizing endemic anopheline populations and their vectorial capacity.

What is your favorite thing about UGA?

I really enjoy the collaborative atmosphere of life sciences at UGA. Groups such as CTEGD provide many opportunities to interact with students and faculty from diverse departments.

Any advice for a student interested in this field? 

Be sure to get involved in research as soon as possible, preferably early in your undergraduate program. Reach out to professors whose work interests you, as well as members of their team. It’s fine not to know what specific topics you want to pursue right away; your initial research experience will help you determine what interests you most, and there will be many opportunities to explore diverse fields in graduate school and beyond.

 

Support trainees like Benjamin by giving today to the Center for Tropical & Emerging Global Diseases.

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Researchers implement new tool to screen drugs for treating malaria relapses

Donna Huber on October 21, 2021

Steve Maher
Steve Maher, assistant research scientist in the Center for Tropical Emerging and Global Diseases, leads a team of researchers who have implemented a new screening tool to determine if a drug candidate kills hypnozoites, the cause of malaria relapses. (Photo by Donna Huber)

Globally, efforts to control malaria caused by Plasmodium vivax are lagging behind that of other species of Plasmodium due to its unique biology. A team of researchers at the University of Georgia, the Institute Pasteur of Cambodia, and Shoklo Malaria Research Unit in Thailand detail a new screening tool and report for the first time a method capable of discovering novel experimental drug compounds for use against vivax malaria. Their study was recently published in Scientific Reports.

The parasite species P. vivax is the most widespread cause of malaria. While not as deadly as malaria caused by P. falciparum, it can cause severe disease and has a significant impact on both national economies and personal finances, in part due to this species’ propensity to cause relapses.

Relapses are caused by hypnozoites, a form of the parasite residing in the liver, which can lie dormant for a period of time before causing another symptomatic blood infection. During this period of dormancy, hypnozoites are not susceptible to standard antimalarials, meaning a patient treated for a blood infection is not fully cured.

“With this assay, we can now tell earlier on in the drug discovery process if a compound is going to work against hypnozoites,” said Steven Maher, assistant research scientist at the Center for Tropical and Emerging Global Diseases and lead researcher on the study. “In this study, we were able to identify three new drugs that kill dormant hypnozoites.”

One of the drugs identified looks promising as a possible new treatment, though Maher said it will need more testing. The other two could be useful in studying hypnozoite biology and increase understanding of such things as the mechanisms of dormancy.

The team’s report also shows how two current antimalarial drugs, chloroquine and tafenoquine, synergistically work together to kill hypnozoites. However, these drugs cannot be administered to children and pregnant women (due to their known side effects), nor to people who lack the enzyme called G6PD. Up to 20% of the population in southeast Asia are G6PD deficient.

“The current drug therapies work well to treat the symptomatic blood stage of vivax malaria,” said Steven Maher. “However, in vivax malaria we need to eliminate hypnozoites to fully cure the patient, and for that we need new therapies.”

To compound the problem, typical mouse models used in malaria drug research can’t determine if the experimental compounds work against hypnozoites because the Plasmodium species that infects mice doesn’t produce them. Additionally, because the assays used as the first step in discovering potential new drug compounds focus on the blood stage of the parasite, researchers need a different kind of assay that will allow them to test these compounds on hypnozoites, which requires a stable culture of liver cells.

“It’s a challenge because you have to get samples from where the vivax malaria is endemic,” said Maher. “Liver cells don’t stay viable in culture for long, and these assays take eight days to show results. The assay itself is difficult to run, but we have a great team of researchers in Cambodia and Thailand that has really helped to make this possible.”

The team is continuing to build better tools to overcome the challenges drug discovery in P. vivax faces as they begin to test these drugs in animal models.

 

This story first appeared at UGA Research.

 

 

 

Outhouses, clean water key to fighting schistosomiasis in persistent hotspots

Donna Huber on October 11, 2021

Dan Colley
Dan Colley, professor emeritus of microbiology and former director of the Center for Tropical and Emerging Global Diseases, devoted much of his career to studying schistosomiasis, a disease caused by waterborne parasites that is endemic in several African nations. (photo credit: Andrew Tucker)

Schistosomiasis, caused by several species of the parasitic worm Schistosoma, is a disease of poverty. The debilitating illness keeps people in a cycle of poverty due to missed educational and employment opportunities. In children, repeated infections often lead to anemia, malnutrition and learning disabilities. While there are no current preventive drug therapies or vaccines, annual mass drug administration (MDA) is often used to treat all elementary school children in countries where Schistosoma species are endemic.

“Treating with praziquantel through MDA programs is really successful in reducing schistosomiasis,” said Dan Colley, professor emeritus in the Franklin College of Arts and Sciences’ Department of Microbiology and former director of the Center for Tropical and Emerging Global Diseases. “However, in our studies we were seeing a few villages that didn’t really respond to annual MDA with lower numbers of infections. And it wasn’t just a few villages—in any given group of 25 study villages, we saw what we’re calling ‘persistent hotspots.’”

Through the work of the Schistosomiasis Consortium for Operational Research and Evaluation, researchers discovered that persistent hotspots (PHS) occurred in study sites in Cote d’Ivoire, Mozambique, Tanzania, Zanzibar and Kenya.

Schistosoma parasites develop in certain species of freshwater snails and are shed into the water where the form of the parasite that infects people can survive up to 24 hours. When an individual comes to the water to bathe, wash clothes, work or play, the parasites invade through the skin.

Several weeks after infection, the worms mature and begin to produce eggs that travel to the person’s bladder or intestines, where they are expelled through urine or stool. When freshwater sources are contaminated with human urine or fecal matter that contain these eggs, the life cycle begins again when the parasite eggs hatch and infect appropriate freshwater snails.

In a recent study published in PLOS ONE, Colley and his colleagues at the University of Georgia, Kenya Medical Research Institute (KEMRI), and Kenya’s Ministry of Health found high use of surface water and low use of latrines were factors associated with being a PHS and likely contributed to persistent levels of Schistosoma infection in these PHS villages—even in the face of annual MDA.

High use of surface water and low use of latrine were found to be contributing factors to persistence levels of Schistosoma infection in a new study published in PLOS ONE. Left: Locals washing clothes at Kisian Beach, Lake Victoria. Right: Dan Colley at a site where sand harvesters work.

The study in western Kenya included both villages responding well to MDA (with a declining level of schistosomiasis) and those that are considered persistent hotspots. All the villages have fewer than 2,000 people, and most range between 500 and 1,500 residents. They often contain a crossroads that serves as the town center with a few shops. While the town center and the nearby houses have electricity, homes farther out might not. Villages considered PHS were located closer to open water sources, and more residents were employed in water-based jobs such as car washing and sand harvesting.

It was also found that these PHS villages had fewer latrines than villages that responded well to MDA, which likely led to more human fecal matter washing into the surface waters. The researchers believe that for these PHS villages, increasing latrine availability and use would reduce Schistosoma prevalence. However, it isn’t just a case of “if you build it, they will come.”

There are several barriers that would need to be overcome. Latrines, commonly called outhouses, are often smelly and attract flies and rats, which then attract snakes. In addition to issues of maintenance, there are social and educational components that need to be considered to change practices. But even when the people are willing, increased latrine use doesn’t always work.

Residents of “persistent hot spot” villages in Africa are more likely to be employed in a water-based occupation, such as car washing, than those in villages with lower rates of schistosomiasis. As the parasites that cause the disease must pass through certain species of freshwater snails before infecting humans, better latrine use in these villages may reduce transmission. (Photo courtesy of Dan Colley)

Colley recounts the story of a group of car washers he and other colleagues at KEMRI and the Centers for Disease Control and Prevention worked with for over two decades. These men are well-versed on Schistosoma, and they decided to build a latrine.

“They knew the life cycle as well as we did, maybe better,” recalls Colley.

The car washers even made it an entrepreneurial pursuit by selling toilet paper for a shilling. However, when the rainy season came, the latrine was flooded, and all that waste was washed into the nearby lake where they worked daily.

This story illustrates just one of the challenges public health officials face in trying to incorporate wells and latrines into national programs to eliminate schistosomiasis. Studies like the one by Colley and his colleagues demonstrate the need to look beyond drug treatment when pushing to move from control to elimination of schistosomiasis.

“We can keep doing MDA, which is helpful, but eventually the worms may become drug resistant,” said Colley. “But with persistent hotspots now being found in everyone’s studies, we know we need to do better. That means we need to advocate for access to clean water sources, sanitation and perhaps ultimately vaccines, as well.”