Understanding the Brain-Eating Amoeba: What’s Behind the Kerala Outbreak?

Advertisment

In an alarming health development, at least 19 people have been reported dead in Kerala after contracting the brain-eating amoeba, Naegleria fowleri. The disease, named Primary Amoebic Meningoencephalitis (PAM), causes brain infection, with a mortality rate of over 97% globally. Kerala has recorded 61 confirmed cases of PAM to date, with fatality rates rising drastically in the past few weeks.

The Current Scenario

Kerala Health Minister Veena George has said, "Unlike last year, we are not seeing clusters linked to a single water source. These are single, isolated cases, and this has complicated our epidemiological investigations."

Initially detected as clusters in districts like Kozhikode and Malappuram, the brain-eating amoeba infections are now appearing sporadically across Kerala. The infected patients also ranged from a three-month-old infant to a 91-year-old. 


More About PAM: Infection Pathway

Advertisment

According to a state government document, PAM targets the central nervous system. "This infection destroys brain tissue, causing severe brain swelling and death in most cases. PAM is rare and usually occurs in otherwise healthy children, teens, and young adults," the report noted.

The report added that "warm, especially stagnant, fresh water acts as a carrier of the brain-eating amoeba. The portal of entry by the amoebae is through the olfactory mucosa and the cribriform plate." 

The oral consumption of contaminated water is not "associated with symptomatic disease," confirmed the report.

Advertisment

Historical infection data confirms the occurrence of PAM in warmer months, putting people involved in swimming, diving, and bathing in warm, generally stagnant freshwater at higher risk. To prevent the rapid spread of the disease, the government has asked people not to swim in stagnant freshwater like ponds.

Unlike COVID-19, PAM infection does not spread from person to person. 


Symptoms of PAM Infection


Similar to bacterial meningitis, PAM starts with headache, fever, nausea, and vomiting. The Kerala government has urged people to seek immediate medical attention if they experience these symptoms after exposure to stagnant water.

"By the time other more common causes of meningitis are ruled out and the diagnosis of PAM is considered, it is often too late to save the patient from the cerebral edema that quickly develops and causes death. Most patients present to medical care with signs or symptoms indicative of central nervous system involvement", the report said.

Advertisment

"The neuro-olfactory route provides N.fowleri quick access to the brain and results in impaired adaptive immune response, causing a very rapid disease course," the document noted.

The symptoms generally appear between one and nine days, while some acute onset have been reported within hours to 1-2 days. Not-so-rare symptoms make diagnosis more difficult, contributing to extremely high mortality rates. 


Is there any Treatment Available for PAM?

Scientists have yet to develop any specific medicine against the brain-eating amoeba. If any patients are diagnosed at a pre-cerebral stage, they are treated with a combination of antimicrobial or amebicidal drugs.

Advertisment

"In theory, the best drug regimen should include an amebicidal drug (or a combination of drugs) with good in vitro activity that is capable of crossing the blood-brain barrier," the report added. 

The state health minister has stressed that "early detection is key".

Impact of Global Warming

The report also warned that global warming is adding to the risk. "Climate change, raising the water temperature and the heat, driving more people to recreational water use, is likely to increase the encounters with this pathogen," it said.

History of Rare Disease Outbreaks in Kerala

The coastal state has reported several rare diseases over the decades. In 2018, the bat-borne Nipah virus claimed 17 lives in a significant outbreak. Since that time, Kerala has witnessed five Nipah outbreaks killing almost 25 people, with hundreds of hospitalizations. Among others, Zika, West Nile fever, Shigella, scrub typhus, and leptospirosis cases have been detected sporadically. 

Advertisment

In collaboration with the National Centre for Disease Control, the state health department is conducting environmental sampling to identify potential sources of contamination. Proper chlorination and cleaning of community wells and water tanks are ordered across the state.