Kerala health authorities are on alert after a spike in cases of Primary Amoebic Meningoencephalitis (PAM), a brain infection with a high fatality rate. This infection is caused by Naegleria fowleri, commonly known as the 'brain-eating amoeba'. This year, Kerala has recorded 61 confirmed cases of PAM and 19 deaths, with many of these deaths being reported in the past few weeks.
State Health Minister Veena George has said Kerala is grappling with a serious public health challenge. The infections, previously linked to clusters in districts like Kozhikode and Malappuram, are now appearing sporadically across the state. Patients range from a three-month-old infant to a 91-year-old. "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," she said.
What Is PAM? How Infection Happens?
According to a Kerala government document, PAM affects 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," it says.
The document flags "warm, especially stagnant, fresh water" as a carrier of the "brain-eating amoeba". "The portal of entry by the amoebae is through the olfactory mucosa and the cribriform plate," it says, adding that oral consumption of contaminated water is not "associated with symptomatic disease".
This puts those swimming, diving, or bathing in water bodies contaminated with this amoeba at a high risk of infection.
The document also flags how 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 says.
The infection does not spread from person to person.
What Are Symptoms Of PAM Infection?
PAM has a very high mortality rate, primarily because it is difficult to diagnose. Its symptoms are similar to bacterial meningitis -- headache, fever, nausea, and vomiting. "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," the document says, adding, "Most patients present to medical care with signs or symptoms indicative of central nervous system involvement".
PAM is more common during warmer months and among people with a history of swimming, diving, and bathing in warm, generally stagnant, freshwater. The symptoms may appear between one and nine days, and their acute onset may occur over hours to 1-2 days. "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," it says.
How Is PAM Treated?
Almost all survivors of PAM in the past six decades were diagnosed at a pre-cerebral stage. "This shows that early diagnosis of PAM and timely initiation of an antimicrobial cocktail might be lifesaving," the document says. Ms George has stressed that "early detection is key".
"The rarity of the disease, delay in diagnosis, fulminant clinical course, and the difficulties in making a rapid diagnosis have hampered the evaluation of drug regimens," the document says.
"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," it adds.
The Kerala government has asked people to seek immediate medical attention if they experience symptoms similar to a PAM infection after exposure to stagnant water.
READ: Surge In Deadly Brain-Eating Amoeba Cases In Kerala: Why And How It Spreads
PAM In Kerala
Kerala reported its first PAM case in 2016, and till 2023, the state had reported just eight confirmed cases. But last year saw a big spike - 36 cases and nine deaths. And this year, 69 cases and 19 deaths have already been reported -- almost a 100 per cent spike.
As the state goes all-out to prevent fresh infections, people have been advised to take preventive measures. They have been advised to avoid swimming or bathing in untreated or stagnant freshwater sources such as ponds and lakes. Swimmers have been advised to use nose clips when entering freshwater, and proper cleaning and chlorination have been suggested for wells and water tanks.
The Kerala health department, in collaboration with the National Centre for Disease Control, is conducting environmental sampling to identify potential sources of contamination.
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