I've posted about this parasite before. It's a tiny, single-celled organism that, although rare, is extremely dangerous. I speak of course about the notorious Naeglaria fowleri. As global temperatures rise, so do the ambient surface temperatures in lakes and other bodies of water. This amoeba is typically non-parasitic, living in the sediments of many lakes. However, when temperatures rise, these amoebas undergo a morphological change into flagellated forms. These new forms are opportunistic parasites that infect unsuspecting swimmers by riding tiny tides of water into the nasal cavities of their hosts. From there, the parasites make their way into the brain, wrecking everything in their path.
Infection with this parasite is estimated to be between 97% and 99% fatal. There have only been two survivors out of the 130+ cases reported in North America since 1962. One survivor was an American and the other was from Mexico. This summer, we mourn the passing of yet another victim, 12-year-old Zachary Reyna from LaBelle, Florida. Zachary was infected on August 3rd after knee-boarding with friends in a drainage ditch near his home. He was taken to Miami Children's Hospital and put on both antibiotics and on miltefosine, a German-manufactured drug often prescribed for treating breast cancer. By August 21st, the boy's family announced that the drugs were successfully slowing the activity of the parasites, but unfortunately Zachary had stopped showing signs of brain activity. A few weekends ago, his family had to make the tough decision to take him off of life support. Zachary's organs were donated to help those in need.
Despite this awful tragedy, this summer also brought a triumph in the battle against this deadly parasite. A few states away and about a month before Zachary's infection, Kali Hardig contracted this same parasite from a water park in central Arkansas. Kali is also 12 years old and was admitted to Arkansas Children's Hospital on July 19th with a severe fever. Kali's treatment began with doctors cooling her body in order to reduce the swelling instigated by the infection. Kali was then treated with miltefosine, which would later be used to treat Zachary. For the next two weeks Kali was on a ventilator. She is now breathing on her own and is responsive, though she had not been able to speak yet as of August 14th (the date of the report I was reading). Tests have confirmed that she is parasite free and doctors say she will survive but will need weeks of rehabilitation. This triumph makes Kali survivor #3 since 1962. To learn more about Kali and her story, check out the Prayers for Kali Le Ann Facebook page.
Before I sign off, let's talk a little bit about Miltefosine. This drug was originally developed as a chemotheraputic used to fight cancerous tumors. It achieves this by inhibiting Akt (a.k.a. Protein Kinase B), which plays an important role in glucose metabolism, transcription, apoptosis (programed cell death), cell migration, and cell proliferation. It is easy to see how this would work for treating cancerous cells. In recent years, the drug has been found to be an effective antiprotozoal drug. Just like with cancerous cells, unicellular parasitic protists can't survive if Akt is inhibited within their cellular membranes. The drug has been show to be effective against leishmaniasis, trichomoniasis, Chagas' disease (in animal studies), a variety of fungal infections (caused by Aspergillus, Candida, Cryptococcus, and Fusarium), and free-living amoeba infections (caused by Acanthamoeba, Balamuthia mandrillaris, and as you've just learned Naegleria fowleri). A compound that is similar to miltefosine structurally (hexadecyltrimethylammonium bromide) is also showing signs of effectiveness against Plasmodium falciparum, the most severe form of malaria.
Moral of the Story
It's important that we continue to advance our medical technologies through continued research. Every day we are getting closer to finding a cure for diseases like primary amoebic meningitis (caused by Naeglaria fowleri). Through tragedy we are reminded that we still have a long way to go, but through triumphs we are reminded that we are at least on the right track. With the summers becoming more and more intense, it is important that we understand how to prevent these often fatal infections just as it is vital that we invest the time, money, and energy into find a way to defeat the parasite when it does manage to infect our loved ones.