Two leftover blood samples of the deceased patient proved crucial in confirming the latest Nipah case in Kerala and in initiating the proven system to check further spread and isolating contacts.

Officials associated with Nipah management said that Kerala's robust surveillance of Acute Encephalitis Syndrome (AES) triggered an investigation into the death of a 23-year-old patient at a private hospital in Malappuram. AES involves clinical neurological manifestations resulting in mental confusion and disorientation due to a disease.

The patient developed symptoms on September 4 and died in a private hospital on September 9. He had shown signs of AES and then progressed to ARDS (Acute Respiratory Distress Syndrome) -- a serious lung condition in which fluid builds up in tiny air sacs in the lungs. Once this happens, lungs don't get filled with air and can't pump enough oxygen into the bloodstream.

The patient had a history of jaundice infection in July and an MRI (magnetic resonance imaging) had shown clinical signs consistent with dengue. Neurological manifestations in dengue infection include encephalopathy, encephalitis and febrile seizures. "The case of AES was recorded in our surveillance system and we did a thorough follow up of this case during the death audit. Fever survey had already started in the area. Field level surveillance by ASHA workers was helpful. Owing to the patient's condition, throat swab couldn't be collected by the hospital authorities. But there were two leftover blood samples which were used for preliminary test in Kozhikode and confirmation test at NIV, Pune. The investigation into AES death of the patient was crucial, because we could activate our protocol very soon," said Dr Anish T S, nodal officer, Kerala One Health Centre for Nipah Research and Resilience.

Nipah is not included in the first level of viral panel tests done for infectious diseases, usually it is done for West Nile fever, HINI etc, said Dr Anish. This further necessitated a follow-up action which was effectively done by the health team. An active surveillance system in Kerala enabled picking up this case post the death of the patient, he said.

There were also confusing signs. The patient had been infected with jaundice in July. So when he got ill on September 4, he sought the treatment of a traditional medical practitioner thinking he had contracted jaundice again. When the patient died, unverified reports spread around saying the youth died of Hepatitis A infection. "It was very important that we investigated and confirmed the cause of death. Around 20 per cent of AES cases were typical of West Nile fever. We got in touch with the neurologist and the medical superintendent of the private hospital where the youth was treated and understood that the youth showed signs of AES and ARDS. They had ruled out Hepatitis, but MRI showed dengue like manifestations and this led to an assumption that the youth had been infected with dengue. We had two blood samples which helped us ascertain the actual cause of death," said Dr Shubin, district surveillance officer, Malappuram.

Manifestation of ARDS and AES in Nipah patients is documented in the study titled 'Clinical manifestations of Nipah virus' by Dr Chandni R and experts of DME Kerala, DHS Kerala, ICMR-NIV, Manipal Institute of Virology, ICMR- National Institute of Epidemiology and Government Medical College, Calicut. In 2018, both encephalitis and ARDS were present in 90 per cent of fatal cases but only in 50 per cent of the nonfatal cases, the study notes.

Rajan Khobragade, Additional Chief Secretary (Health), said that over the years, Kerala has perfected the system to deal with Nipah and other infectious diseases. "Time stamping, which we introduced during Covid, was also promptly done here. In this case, we already put in a system to monitor AES cases and this is done across the state so that we can act accordingly. This surveillance helped us in identifying the cause of death. They didn't have cerebrospinal fluid or throat swabs, but there were two leftover blood samples. Thankfully some of the close contacts, including his friends and family, have tested negative. We are still insisting on home quarantine as an extra precaution," said Khobragade.