KARACHI, July 21: The Disease Early Warning System of the World Health Organisation has confirmed four deaths caused by waterborne Naegleria infection — primary amoebic meningoencephalitis — in the city this year, said a source in the Sindh health department on Saturday.

Sources told Dawn that after the reports emerged that eight or nine people had died due to PAM, a DEWS Karachi team visited various government and private hospitals to investigate the situation.

The objectives of the DEWS team included outbreak control measures, social mobilisation, evidence collection and identification of technical needs and to provide diseases prevention facilities if needed by the provincial health department.

Sharing information regarding the deaths due to PAM with Sindh health department officials, the DEWS team said the Liaquat National Hospital had provided information about three dead.

The three patients who died on July 6, 11 and 14 were between 22 and 27 years of age. One of them had a history of swimming.

A consultant microbiologist at the Aga Khan University Hospital told the DEWS team that one patient of Negleria meningitis, who was admitted to the hospital on July 16, died on July 18. He was 44.

The microbiologist also maintained that the PAM disease caused by a free-living amoeba — Naegleria fowleri — was not a new disease in Pakistan.

The AKUH admitted first such case in 2005, following which some cases had been reported almost every year, the consultant said. According to the consultant who spoke to the DEWS team, the AKUH had 17 such cases reported in 2011.

A source in the DEWS Karachi team said that no other tertiary care hospital in the public or the private sector had reported any admission or death of an individual affected by PAM till Friday.

Only one of the four cases had a history of swimming and as such it was not accurate to say that humans came into contact with the Naegleria fowleri infection by swimming or bathing in pools or diving only, said the source.

The source added that PAM had been included in the list of priority or highly communicable diseases of DEWS for active surveillance.

The DEWS set-up in Sindh was linked with over 50 big government and private hospitals to respond to reportable diseases alerts and outbreaks, sources said.

A source in the health department said the health authorities were considering taking on board all stakeholders and relevant departments on provincial and district levels for control of amoebic meningitis and other interventions.

When contacted, a WHO surveillance officer in Karachi said that DEWS was working with the provincial health department and in close liaison with infectious disease specialists and collecting related information from big hospitals in Karachi and
Hyderabad.

In the meantime, a senior microbiologist from another hospital, seeking anonymity, said the amoeba, Naegleria fowleri, could not be detected from contaminated stagnant freshwater.

“This can only be detected from the cerebrospinal fluid [CSF] culture, which is done only by a few laboratories in Karachi.”It was further said that the cases were not coming from a single area, but coming in sporadic way and, therefore, intervention in only swimming pools or specific reservoirs would not help.

“The sources of the infection may be the main water reservoirs meant for supplying water to Karachi and the related conveyer system,” said another expert, suggesting a close scrutiny of the Karachi Water and Sewerage Board for a 100 per cent chlorinated water supply to the whole city.