When five-year-old Fadva came to the Kozhikode Medical College Hospital with a headache, fever and vomiting, Dr Jayakrishnan, additional professor of Pediatrics, saw signs of what he feared might be a brain infection. He performed a lumbar puncture on her, during which a needle is inserted to get a sample of the cerebral spinal fluid (CSF) from the brain. At first, it seemed like bacterial meningitis, an infection of the membrane covering the brain and spinal cord. But then he learned that the child had bathed in the Kadalundi River of Malappuram a few days before. It struck him that the infection could have been caused by amoeba present in warm freshwaters. Tests confirmed that Fadva was infected with primary amoebic meningoencephalitis (PAM), a lethal disease with a fatality rate of 97%. Fadva died on May 20. In less than two months, two more children would die of the disease, and two others infected.
“Five cases in less than two months is really unusual when, world over, there have been less than 500 cases in all of time,” says Dr Aravind Reghukumar, Head of Department of Infectious Diseases at the Thiruvananthapuram Medical College.
“We don’t know the cause of this, but there is reason to believe that it may have to do with global warming. Naegleria fowleri – the amoeba that causes the disease – is known to be more active in warm waters. But then the question would be why is it only seen in Kerala now, if it is an effect of global warming, and that too in the northern parts of the state?” Dr Aravind explains, adding that cases elsewhere may have gone undetected.
The five cases so far were from Malappuram, where little Fadva hailed from; Kannur, where a 13-year-old girl called Dakshina got an unusually delayed reaction and died; two cases of boys in Kozhikode; and one, Dr Aravind informs, in Thrissur.
Of the two boys in Kozhikode, 12-year-old Mridul passed away after undergoing treatment for days. The other boy, a 14 year old, is responding to treatment at the Baby Memorial Hospital, says pediatric intensivist Abdul Rauf, the doctor who has taken care of three of the cases.
Of the three cases in Baby Memorial, Dakshina’s infection was caused not by Naegleria fowleri but another amoeba, called the Vermamoeba vermiformis, says Dr Abdul Rauf. The symptoms too, unlike other cases, manifested much later. Dakshina likely contracted the disease from a swimming pool in Munnar during a school trip in late January. She began showing symptoms only in May, much after the usual one week, and passed away in June. Amoebic meningoencephalitis was diagnosed posthumously after her death on June 12.
The infection was first reported in Kerala in Alappuzha in 2016, later cases being from Malappuram, Kozhikode, and Thrissur. Last year, a 15-year-old boy succumbed to the infection in Alappuzha.
Why are children infected?
The disease is known to affect mostly children, and sometimes young adults in their early 20s. The cribriform plate through which the amoeba travels to reach the brain, is believed to be more porous in younger people, and this, scientists think, may be a reason for the increased occurrence in that age group.
The amoeba enters the human body not through drinking water, but through the nose. Dr Indu PS, Professor and HOD of Community Medicine at the Kollam Medical College, says that when one swims or bathes in a pool that has amoeba, it enters the brain through the nasal route. “The olfactory nerve or the nerve of smell goes from the interior part of the nose to the brain. It is through that tract that the amoeba will reach the brain. That's why Naegleria fowleri is called the brain-eating amoeba,” she says.
Symptoms get rapidly worse as the infected persons develop neck rigidity, seizures, often followed by coma, before death. In the few cases where a patient survives, there would have been early detection and treatment. The problem is however in detecting the disease early enough, that is, within 48 hours of the infection. Symptoms ideally start showing in a week. Even then, it is rarely traced to contact with water.
“It is very difficult to find the water contact, to even suspect the disease. In some cases it can even be indirect contact. The probability of catching the infection from amoeba-infected water is one in 26 lakh, it is that rare,” Dr Aravind says.
In fact, when Fadva bathed in the Kadalundi River, there were other children with her. A few of them also had mild infections including a running nose, but only Fadva was infected with PAM. “It is not clear what causes the infection in some while it doesn't in others. The child may have had a predisposition. Perhaps she splashed more or spent more time in the water, causing the amoeba to come to the surface,” Dr Jayakrishnan says.
The amoeba Naegleria fowleri is seen in heat springs and lakes and prefers the heat, says Dr Indu. “That's why there is always a question — can global warming, an increase in the overall ambient temperature, be one of the reasons that there is an increase in the number of cases? These are possibilities. But will it become a rapid infection like Dengue, or other viral diseases? Unlikely.”
What precautions can be taken?
Doctors brush away concerns of amoebic meningoencephalitis being a contagious disease. Advisories issued by the State’s Health Department and Chief Minister Pinarayi Vijayan asked people not to panic, but to ensure that the swimming pools they enter are regularly chlorinated. Nasal plugs and clips have been recommended, in addition to a few basic precautions — do not enter contaminated water, avoid splashing water on the nose, and consult a doctor as soon as you see symptoms of the disease. Government guidelines including a standard operating procedure are expected to be released this week.
Treatment includes a combination of five drugs, four of which are already available in the state. The fifth, a drug called Miltefosine, has been bought from elsewhere.