Human Blood Flukes (Schistosoma sp.) |
As I began doing a little light research, I ran across some articles that I am surprised I haven't heard more about. Apparently back in June, scientists in Brazil successfully created a vaccine for Schistosomiasis in mice! This is the first time (to my knowledge) that a vaccine has ever successfully been created to battle helminths! Before I get too carried away, Let's talk a little about Schistosomiasis.
Schistosomiasis-a.k.a. "Bilharzia"-a.k.a. "Snail Fever" as an NTD
This is a disease caused by a trematode (flatworm) belonging to the genus Schistosoma. There are a few that cause disease in humans and many that cause disease in other animals. Most human cases are caused by S. mansoni (Throughout Africa, Brazil, Suriname, Venezuela, and a few islands in the Caribbean), S. haematobium (Throughout Africa and in parts of the Middle East), or S. japonicum (Indonesia, parts of China, and Southeast Asia). There are a few others that infect humans, but they aren't nearly as widespread. (S. mekongi in Cambodia and Laos and S. intercalatum in Central and West Africa) None of these worms are not found in the US, but pose major threats to public health in Asia and South America. Schistosomiasis is a devastating disease that infects more than 200 million people globally. According to the CDC, it's second only to malaria in terms of impact on global health, and is considered one of the five NTDs (Neglected Tropical Diseases). The other four are Trachoma, Onchocerciasis, Lymphatic Filariasis, and Guinea Worm Disease. NTDs kill about 534,000 people worldwide every year. Sadly, the treatment cost for most NTD mass drug administration programs work out to less than $0.50/person/year, and these programs are still underfunded. The CDC also reports that 149 countries and territories are affected by at least one NTD. In fact, I'll let the CDC have the last word about NTDs:
"More than 1 billion people—one-sixth of the world's population—suffer from one or more Neglected Tropical Diseases (NTDs). NTDs are a group of infectious diseases that are the source of
tremendous suffering because of their disfiguring, debilitating, and
sometimes deadly impact. They are called neglected because they have
been largely wiped out in the more developed parts of the world and
persist only in the poorest, most marginalized communities and conflict
areas. Social stigma is a major consequence of NTDs. In addition to causing
physical and emotional suffering, these devastating diseases hamper a
person's ability to work, keep children out of school, and prevent
families and communities from thriving."
Distribution of Schistosomiasis |
Biology of Schistosomes
Egg of S. mansoni (Note the lateral spine.) |
Biomphalaria sp. Intermediate Host for Schistosoma |
Generalized Life Cycle of Schistosomes |
Brazilian children suffering from Schistosomiasis. |
Tortuous varicosities in a 24-year-old man suffering from chronic schistosomiasis. |
The Whole Point of this Post
An antihelminthic drug, Praziquantel, is an effective treatment for this disease. However, after treatment, many people become reinfected because they return to conditions that are conducive to parasite proliferation. Efforts to prevent the disease have focused on killing off the intermediate host snails and telling people to stay out of the water. Neither of these "preventative" measures has been entirely successful. Snail-killing chemicals often harm other important species in freshwater ecosystems and must be administered fairly often to keep snails from returning. And let's face it, people need water. People in third world countries don't always have sources of clean water, and often people defecate in or near water sources from which they drink, or use for bathing or for livestock. Domesticated animals need water too. Just like humans, these animals can carry the parasites and pass eggs in their waste products. These products often find their way into freshwater sources.
Researcher holds a vial of SM-14. |
After years of progress, Brazilian researchers have developed a vaccine for this disease! The vaccine is called Sm-14, and may be the first antihelminthic vaccine ever created. It's also extremely safe. From what I understand, they found proteins on the worms that could be manipulated with enzymes to induce immunological protection. The proteins were located on the tegument (skin) of the worms. Research has shown that using these proteins in a vaccine tested on mice either eliminated or at the very least greatly reduced the infective capability of the parasites. Immunization combined with drug treatment and sanitation efforts offer the best solution to protecting those affected by the devastation of this disease. Brazilian researchers believe that immunization of populations in areas of endemic schistosomiasis can be completed in five years, eradicating the disease from such places.
An awesome poster showing the lead SM-14 researchers: (from left to right) Peter Hotez, David Dunne, and Alan Fenwick. |
Moral of the Story
This. Is. HUGE. Seriously, this is history in the making. The development of Sm-14 was publicly announced on December 6th, 2012. For those of you counting, yes, that was a mere 10 DAYS AGO! Just over a week ago, the results of clinical trials were released giving hope to the 200 million+ people who suffer from the second most-devastating tropical disease (just behind malaria). Be excited that you are living at a time when this medical breakthrough occurred. Then be sad that many people have never heard of schistosomiasis despite how many lives it's claimed. Then be excited again that the people who HAVE heard of it...the people who SUFFER from it or have friends or family members suffering from it at this very moment...have something to look forward to when vaccine administration programs begin distributing these little bottles of hope. This could very well be the beginning of the end for schistosomes. Maybe the Mayans were talking about them rather than about us....we will see what happens on Dec. 21st! :p
P.S. In looking for photos, I stumbled onto a website for an organization called United Against Infectious Diseases (UAID). Below is their mission statement and one of the posters they've created relating to this post.
"To empower students in making our world a better,
healthier place through awareness, prevention,
and treatment of infectious diseases."
healthier place through awareness, prevention,
and treatment of infectious diseases."
Love this post! Helped a lot with my project, Thanks!
ReplyDeleteplease admin help me share this to those who still suffering of this disease. As a sign of gratitude for how my wife was saved from Schistosomiasis, i decided to reach out to those still suffering from this.
ReplyDeleteMy wife suffered Schistosomiasis in the year 2013 and it was really tough and heartbreaking for me because he was my all and the symptoms were terrible, she always complain of abdominal pain and swelling , and she always have skin itching. we tried various therapies prescribed by our neurologist but none could cure her. I searched for a cure and i saw a testimony by someone who was cured and so many other with similar body problem, and he left the contact of the doctor who had the cure to Schistosomiasis . I never imagined Schistosomiasis . has a natural cure not until i contacted him and he assured me my wife will be fine. I got the herbal medication he recommended and my wife used it and in one months time he was fully okay even up till this moment she is so full of life.Schistosomiasis . has a cure and it is a herbal cure contact the doctor for more info on drwilliams098765@gmail.com on how to get the medication. Thanks for reading my story