The Global Burden of Schistosomiasis presented by Farah Mechref
Endemic in 74 countries across Africa, the Middle East, South America, and Asia, schistosomiasis is a neglected tropical disease caused by flatworms or blood flukes known as schistosomes. About 440 million individuals are infected with these trematodes, which reside in the blood vessels of their definitive host and lead to different clinical manifestations depending on the species. In regions endemic for schistosomiasis, the most prevalent form of the disease is
chronic schistosomiasis, resulting from repeated immunological reactions to eggs trapped in organ tissues. Infection begins when individuals enter bodies of water that contain contaminated snails that have released infectious cercariae. These cercariae penetrate the skin of the human host and produce an allergic dermatitis at the site of entry or a “swimmer’s itch.” Antigens are then released from their eggs, which stimulates a granulomatous reaction composed of T cells, macrophages, and eosinophils, resulting in the clinical disease.
Acute schistosomiasis typically presents with sudden onset of fever, malaise, myalgia, headache, fatigue, and abdominal pain lasting 2–10 weeks, with eosinophilia noted on lab findings. Chronic infection cause granulomatous reactions and fibrosis in affected organs, which results in clinical manifestations
that include:
-In S. mansoni and S. japonicum: upper abdominal discomfort that then shows palpable, nodular hepato-spenlomegaly with eventual development of portal hypertension from fibrosis of portal vessels and resulting ascites and hematemesis from lethal esophageal varices.
-In S. haematobium: hematuria, which is so endemic that it’s thought to be a natural sign of puberty for boys and confused with menses in girls, with eventual development of squamous-cell carcinoma of the bladder.
Currently, the only control measures available include (1) mass treatment with Praziquantel (Biltricide) in communities where schistosomiasis is endemic, (2) introduction of public hygiene programs to provide safe water supplies and sanitary disposal of stool and urine, (3) snail eradication programs using molluscicides, and (4) vaccination development to create a more durable and sustained reduction in transmission.
Discussion Questions:
- Knowledge of transmission and preventative measures play an important role in schistosomiasis control, what other endemic conditions could be better tackled with improved patient education?
- With 230 million actively infected patients and another 200 million with latent infections, is a vaccine worth the resource distribution or should funding go towards expanding the anti-parasitic classes available for treatment?
Resource Equity in a Disease Outbreak by Alison Neely
The Ebola virus disease of 2013-2016, centered in West Africa, was considered one of the most threatening cases of infectious disease outbreak in modern history up until the emergence of Covid-19 in 2019. Due to the high case fatality rate of Ebola, the core element of the outbreak response was effective case identification and rapid isolation; treatment centers were quickly overwhelmed and experienced limited bed supply and staff time. A study drawing from interviews with senior healthcare personnel involved in this Ebola outbreak response aimed to identify the ethical issues involved in such a response and to create a framework of ethical guiding principles for future responses.
The framework proposed after analysis of the participants’ interviews was split into four categories: community engagement, experimental therapeutic interventions, clinical trial designs and informed consent. Community engagement stood out as a key element both in the framework and in the journal club discussion that followed. Engagement can include promotion of collaboration and open dialogue, incorporation of community insights into decision-making processes, encouragement of transparency, building trust, and reflecting on context-specific cultural values. As future physicians with special interest in global medicine, these ideas of respecting cultural context and complete inclusion of the local community in response efforts were highlighted as very relevant to our future practice.
Discussion Points:
- Have the principles presented here been followed in the global response to the Covid-19 pandemic?
- Our discussion also focused on the parallels and differences between this Ebola response and the global response to the Covid-19 pandemic, calling attention to the ways that the response both followed and diverged from the framework presented in this article. As the idea of a disease outbreak has become part of daily conversation in the last 2 years, investigations and discussions such as this will become increasingly relevant and important. We also touched on the idea that our global response to Covid-19 may have been very different, and potentially weaker, if the Ebola outbreak had not occurred when it did.
Wrap up!
As you can imagine, our mentees had a wonderful discussion surrounding these three topics! We are thrilled to be able to present a brief summary of their work here. Please stay tuned for details about our upcoming meetings. Connect with us through one of our contact options listed below if you are interested in attending!
Thank you to our authors and presenters!
Farah Mechref, MS4
Texas Tech University Health Sciences Center
Alison Neely, MS4
Albert Einstein College of Medicine
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