Kerala is rich with 44 major rivers, numerous canals crisscrossing the state, innumerable ponds, and other water bodies. Somewhere in these waters lurks a brain-eating amoeba that claimed the life of a 15-year-old boy in Alappuzha.
The scientific world was shocked and helpless as the amoeba, Naegleria fowleri, gnawed away Guru Dutt's life. Its attack is so lethal that once it causes Primary Amoebic Meningitis (PAM), the patient's chances to survive are bleak.
The only relief, however, is that the probability of getting affected with PAM, too, is rare.
Guru Dutt got infected while bathing in a canal near his residence at Panavally in Alappuzha. Incidentally, another resident of Alappuzha, Akhbar, too, had succumbed to the infection a few years ago. Akbar got the infection from a canal in front of his house at Pallathuruthy.
Michelle of Kozhikode, too, was fatally infected while swimming in a pool three years ago. Doctors are worried since known preventive measures are not capable of keeping Naegleria fowleri away.
The scientific world has estimated that the death rate due to amoeba-caused PAM is 97 percent, reflecting the lethality of the protozoa. In the US, of the 157 people affected, only four could be saved.
Amoeba kills 12 in India
A study conducted in Virginia provided a shocking result. Post-mortem examinations conducted on 16,000 people who had died of meningitis revealed that five of them had PAM. However, no one was aware of the infection until the autopsy report came.
Akbar of Alappuzha was the 10th Indian to die of the disease. With the deaths of Michelle and Guru Dutt, the toll has gone up to 12. The delay in detecting the infection increases the risk.
The unicellular organism, Naegleria, feeds on bacteria and prefers warm waters. Only one species of Naegleria affects the human brain — the Naegleria fowleri. They live in warm freshwater and it explains its presence in Kuttanad and its neighbourhoods with abundant water bodies.
The possibility of the amoebae being washed downstream from other places during the rainy season could not be ruled out. The free-living microbe could not be seen by the naked eye. They could be detected only through a microscope. They thrive in freshwaters — ponds, canals and rivers — and in soil.
Incidentally, Naegleria fowleri is not found in brackish or cold waters. But they can survive in tap water. Their presence could not be detected since they do not alter the taste or colour of the water. Summer is its preferred season, especially when the temperature is 46 degrees Celsius.
The amoeba enters the human body through the nostrils and travels through the nerves to the brain. Swimming, diving underwater, or spending long periods in water increases the possibility of getting affected. PAM has been reported in deep-sea divers as well.
Incidentally, Naegleria fowleri affects children and youngsters more. The exact reason for it affecting the youngsters has not been found. However, it is assumed that youngsters are more susceptible to the infection since they tend to spend more time in the water.
The infection shifts to rapid mode once it enters the body. It multiplies after reaching the brain and starts destroying the cells. They mostly remain in the olfactory nerve.
The symptoms of PAM usually start within five days after infection. Headache, fever, lack of appetite, sore throat, and hallucinations are the common symptoms. Cerebral edema (swelling of the brain), too, has been reported.
Once the symptoms become evident, the infection progresses rapidly and may kill the patient in five to 10 days.
Small, but deadly
The brain-eating amoeba was first found in Australia in 1965. Ranging from eight to 15 micro centimetres, they are as big as 1/10th of a normal strand of hair.
The organism, which remains a cyst in adverse conditions, multiplies in favourable circumstances. Though it normally feeds on bacteria, it eats living cells on reaching the brain.
Despite medical science making giant strides, a drug against this brain-eater is yet to be developed. Drugs against other amoeba species have been successfully tested in lab conditions. Though these drugs eradicate the amoeba in lab conditions, they are not effective in the human body.
So far, only two people were effectively treated in the world. The doctors used antifungal drugs including Amphotericin. However, these drugs' efficacy has not been proven.
However, some experiments are raising hope. Additionally, it has been discovered that the human body produces antibodies against the amoeba.
Naegleria fowleri habitats
Warm freshwater, ponds, rivers
Hot water springs
Thermal and industrial plant effluents
Unclean water supply networks
Swimming pools, water bodies that are not disinfected
Sand at the bottom of water bodies
The above are the possibilities included in a report by the Centre for Disease Control and Prevention.
The amoeba infection is non-communicable. They feed on microbes normally seen in sediments at the bottom of water bodies. Hence, it mostly infects those who dive deep in the water.
Ingesting amoeba-infested water won't cause the infection, but water entering the nose may lead to the disease. Swimming, diving deep into the water, spending a long time in the water, conducting errhine therapy using contaminated water, etc., could help the amoeba enter the human body.
Though tap water entering the nostrils could be dangerous, bathing under the shower is considered safe. Experts said the amoeba enters the human body only through the nose.
Akbar and Guru Dutt remind us of the danger lurking in any water body. Using nose clips while using swimming pools could ensure safety to a certain extent. The presence of amoeba in water could not be tested easily. It requires tests that last weeks.
How could we know if the amoeba has infected us? In fact, there is no way until the infection is complete. According to studies, the disease is diagnosed only during its final stage in 75 percent of cases. Mostly, the relevant tests are conducted when all other treatments fail. Additionally, there are no rapid tests to find the presence of the amoeba.
Does climate change present an environment conducive to the growth of Naegleria fowleri? No scientific study has been conducted in this direction. Remember, the amoeba thrives in warm environments. Climate change and global warming are raising the temperature of water bodies. The scientific world is worried that climate change could provide safe havens for the amoeba.
Courtesy: Dr. T K Suma, Former Principal, T. D. Medical College, Alappuzha; Dr. R. Sajith Kumar, Professor Emeritus, Infectious Studies Centre, Kottayam Medical College.