Nipah in Kerala: State govt launches search for source of virus; identification may be difficult compared to last year

The Kerala government has launched an extensive search for the source of the deadly Nipah virus that has staged a comeback in the state after a year.

The virus was found to have spread last year from a 26-year-old youth who contracted it after consuming a fruit bitten by a fruit bat carrying the virus. Though the source of the infection last year was a tiny village near Perambara in Kozhikode district, scientists took three months to identify the carrier of the virus.

The search this time is going to be difficult, as the 23-year-old youth hailing from North Paravur in Ernakulam district who has been tested positive for Nipah virus had stayed at multiple places in three districts during the incubation period that normally ranges from 4 to 14 days.

Dr Anoop Kumar of Baby Memorial Hospital, Kozhikode, who diagnosed the Nipah virus in the victims in May 2018 after getting their samples tested at the Manipal Centre of Virology, said that identification of source is important to find out whether the virus has spread to anywhere else.

 Nipah in Kerala: State govt launches search for source of virus; identification may be difficult compared to last year

A well is being covered to contain the deadly Nipah virus. File image. Rejimon K

He said that the search during the outbreak last year could be confined to Perambara as the virus was found in four members of a family from there. The others contracted the virus in the hospitals where they were treated. He said that it would be easy for the medical community to contain the present outbreak if they can find out how the index patient had contracted the virus.

Kumar said it may not be difficult as the patient is alive. However, the youth has not been able to give any clue regarding the source so far. Doctors treating him feel that he may be able to identify the source when he becomes normal. Though his condition is stable, doctors do not want to probe him now as it would put him under stress.

The health department had initially suspected Thodupuzha in the hilly district of Idukki as the epicentre of the infection. However, district medical officer N Priya said that the youth had developed fever four days after he and his friends left the district.

Priya said that the youth, who came to Thodupuzha to write a test, had stayed for only one day in the town. She pointed out that no one in the area where the youth stayed or anywhere else in the district had shown any signs of the infection so far. She said there was not even any case of severe fever anywhere in the area.

Similarly, no case of infection has been reported from Thrissur, where the youth and his friends stayed for four days. Out of 24 people who came in contact with the youth in the district, only one person has developed fever. The doctors treating the person at a primary health centre in Thrissur said that it was a normal fever that might have been caused due to the fear of Nipah.

The youth from Paravur had developed fever during his stay in Thrissur but he left for his native place after his condition worsened. Before he was shifted to a private hospital in Ernakulam, he had undergone treatment in two hospitals at Paravur.

Three nurses who treated the youth in the private hospitals and one of his friends who had come in close contact with him have developed fever. However, doctors said that the condition of none of them is serious. They are now under the close observation of the doctors.

The state government, however, has not excluded any place from the scope of the search. The government has asked the departments of Animal Husbandry, Kerala Veterinary University and the Wildlife Department to depute teams to the concerned districts. A central team from National Institute of Virology (NIV), Pune has also arrived in the state to help the state officials.

Dr PC Sunil Kumar, director of state Animal Husbandry, who is coordinating the search, said three teams from the department’s laboratories at Thiruvananthapuram, Palakkad and Tiruvalla have already begun the search in Idukki, Thrissur and Ernakulam districts.

He said that their primary focus was fruit bats, which were found to be the carriers of the virus that led to the death of 17 persons in Kozhikode and Malappuram districts in May last year. However, he said that the teams would also extend the scope of the search as Nipah virus can be transmitted to humans from other animals, including pigs, or contaminated foods or directly between people.

Pigs were the carriers of Nipah virus when it first broke out in Malaysia in 1999. Most human infections resulted from direct contact with sick pigs or their contaminated tissues during the outbreak in Malaysia, which also affected Singapore.

In subsequent outbreaks in Bangladesh and eastern parts of India, consumption of fruits or fruit products (such as raw date palm juice) contaminated with urine or saliva from infected fruit bats was found to be the most likely source of infection. According to scientists, fruit bats of the Pteropodidae family are the natural hosts of the Nipah virus.

Sunil Kumar said that the teams from Animal Husbandry will be looking for fruit bats and pigs in all the three places. They have been asked to catch hold of fruit bats and collect samples of their blood and saliva for testing.

He said that efforts to identify the source would not be difficult this time as his team was involved in the operation in Kozhikode. The samples of one of the two species of bats collected by them were confirmed to be the carriers of the virus. The first batch turned out to be insectivorous bats, which have been not connected with human infections even though they could host Nipah.

The Animal Husbandry official said that the experience they got last time would help them in catching the right species this time and identifying the source without much delay. The health community is looking forward to this to find out the reason for the spread of the virus and decide the scientific measures they have to take to contain the outbreak.

Updated Date: Jun 04, 2019 22:25:08 IST