KARACHI, July 20: A fatal waterborne infection that recently caused death of four young men in the city had also claimed the life of a high-level official of the armed forces over a month ago and so far this year seven patients have died of the disease, investigations carried out by Dawn show.

According to sources, the official of the armed forces died of primary amoebic meningoencephalitis (PAM) at the PNS Shifa Hospital.

He was brought with initial symptoms of severe headache, mild fever and vomiting and later developed signs of irritation, agitation and loss of orientation finally leading to coma and a fatal heart attack. At least four cases of the infection, with one patient having a history of swimming have been reported at the PNS Shifa Hospital over the past 12 months or so. All patients, under 45 years of age, died.

Officials at the hospital, however, refused to provide any details about the cases and said that they could only be shared with the permission of the director general of the medical services (DGMS), naval headquarters, based in Islamabad. The DGMS was not available for comments despite repeated attempts to contact the officer through phone and email.

PAM is defined in medical literature as a rare but typically fatal infection caused by Naegleria fowleri, a free-living amoeba found in freshwater environments like rivers, lakes, springs, drinking water networks and poorly chlorinated swimming pools.

It needs to be recalled that four patients, all between 20 and 27 years of age, died of PAM over the past two weeks. Three patients were admitted to the Liaquat National Hospital (LNH) whereas one to the Aga Khan University Hospital (AKUH). Earlier, three cases were reported at the AKUH.

“One of the patients was admitted to the hospital whereas cerebrospinal fluid [CSF] samples of two infected patients were brought for diagnosis at the hospital which tested positive. All three patients, two below 30 and one under 45 years, died,” Dr Afia Zafar, professor at the department of pathology and microbiology of the Aga Khan University and Hospital (AKUH), said.

Dr Zafar refused to reveal the identity of the patients whose CSF samples were brought for diagnosis at the hospital.

Asked about the nature of the infection, she explained that the disease represents clinically in a fashion that may be indistinguishable from bacterial and viral meningitis resulting in delayed appropriate diagnosis and treatment.

“High index of suspicion is required from treating physicians and clinical laboratories, especially in the summer months. The frequency of this parasitic disease increases in summer months due to two reasons: higher temperature of water facilitates the germ’s propagation while it’s also the time when recreational activities associated with water also increases.

“The germ is believed to gain entry into the central nervous system (CNS) via the nasal passages. When a person jumps into the water without closing their nostrils, water enters forcefully in the nose and directly hits the mucosal surface of nasal cavity roof. This damage facilitates penetration of organisms in the CNS. The illness attacked a healthy person three to seven days after exposure to contaminated water with symptoms of headache and slight fever and in some cases associated with sore throat and rhinitis [common symptom is a stuffy nose].

“The disease progresses fast with rising fever and increasing headache, vomiting and stiff neck. Deep coma is followed by cardio-respiratory failure,” she said, pointing out that early medical intervention and institution of certain drugs could save life. The microorganism, she said, was wrongly referred to as a brain-eating amoeba since it didn’t eat the brain, but infected the brain tissues and its covering membrane.

“It is considered a rare disease because generally doctors do not suspect for the disease. But, as cases are being reported, it doesn’t appear to be the case in the city. Three to four cases of the same infection were also reported last year at the hospital,” she said, adding that the worrisome aspect of the disease was that most patients which she had seen over the past few years didn’t have a history of swimming.

This factor, according to experts, raises serious doubts over the quality of water being supplied to the city as proper chlorination kills the specific germ.

According to sources, a case of the same infection was reported at the South City Hospital in Clifton last summer. The patient was a teenage boy. The private hospital administration also refused to provide details about the case, arguing that it was against patient confidentiality rights.

No case at govt hospitals?

Asked about the situation at the Jinnah Postgraduate Medical Centre (JPMC), Dr Syed Owais Ahmed, an assistant professor at the JPMC central laboratory with 29 years of experience, said: “I haven’t seen this organism in my whole life, though I have read about it. By that I do not mean that it doesn’t exist in the environment and infects people. Actually, patients in most cases were already on some specific medicines on the advice of general practitioners before they report at the hospital. As a result, it becomes difficult to isolate or identify the organism from their bodily fluid.”

Some experts, however, do not completely agree with this point of view and blame the lack of an efficient diagnostic system at public sector hospitals for failure in identifying the organism.

“The CSF sample required to detect the specific amoeba must be brought within 20 minutes to the laboratory for test. Otherwise important features are wasted. This is practically not possible at pubic sector hospitals because of the way they operate,” a JMPC microbiologist said.

According to Dr Afia Zafar, the germ can be easily seen under a microscope but what is required is awareness and training of clinical microbiologists and laboratory technical staff. “The test is very simple; you just need a drop of CSF, put it on the slide and examine under the microscope. One can identify them by their motility and morphology. They should know that such a germ exists and how to look for it,” she said.

According to an AKUH research published last year in an international publication which provided details of the cases reported at the hospital and LNH in 2008 and 2009, none of the 13 patients brought to these hospitals survived.

All were men, residents of Karachi and their ages ranged from 16 to 64 years. Most cases involved healthy young adults with acute, fatal disease. Only one patient had a history of swimming. Domestic tap water samples were also tested in one case and the germs were detected in the test.

The study also gives possible explanations about the presence of Naegleria fowleri amoebae in Karachi’s municipal water supply and says that water obtained from two suburban freshwater lakes is not adequately filtered and chlorinated.

“Changing climatic conditions may have contributed to the sudden surge of PAM. However, reasons need to be determined by an urgent epidemiological investigation into relevant environmental factors,” the study recommends.

According to the information available on the net, three cases of the infection were reported in the US last summer. Two people died from infested neti pots (a container designed to rinse the nasal cavity) in Louisiana.

To date, less than 300 cases of PAM have been reported worldwide from 1965 to 2008 and attributed to N. fowleri. Patients survived only in three cases.

Preventive measures

At the individual level, experts suggest people to clean their underground and overhead tanks on regular basis, clean nose softly with tap water and try to use boiled water to irrigate sinuses, neti pots should be kept and stored dry, avoid swimming in ponds, freshwater pools, private swimming pools not chlorinated as per international standards and guidelines.

At the public health level, the government, they say, should ensure supply of chlorinated water supply for domestic use, monitor and ensure quality checks of water supply and swimming pools and make water filter plants functional.