Wednesday, June 06, 2018

Nipah Infection, Kerala: Don't Blame Bat's Alone.

Nipah infection in Kerala: Don’t blame the bats alone; improve public health

  • Perambra, a village in Kozhikode district of Kerala has been in the news after illness and death were reported due to Nipah virus infection.
  • Even while the spread of the infection has been contained, it is still a mystery from where the virus that caused the first human infection had come.
  • The Kerala Government has been issuing advisories through mass and social media to prevent scare mongering.
  • Bat experts say that instead of blaming the bats there is a need for greater attention on maintaining public health.

Targeting bats

Bats have been blamed as the cause for Nipah as they are the natural host of the virus. It is due to this reason that the Kerala Government had to strictly warn public not to indulge in any activities that can harm the animal.
Merlin Tuttle, American ecologist, founder & executive director of Merlin Tuttle’s Bat Conservation told Mongabay-India in an email: “Virtually every animal species that has been carefully studied has some virus of potential risk to other species. In the past four decades, so-called ‘emerging diseases’ have killed fewer than 20,000 people worldwide, and there is no more than unsubstantiated speculation for blaming even half of those deaths on bats,” he added. He also reminded that some of the most valued crops rely heavily on flying foxes and their closest relatives for pollination. “Flying foxes are also Southeast Asia’s most important long-distance seed dispersers, essential to reforestation,” he stated.
He also said that bats in reality have one of the world’s finest safety records when it comes to living with people. Hundreds of bat biologists, millions of people who eat bats, and the millions more who share cities with huge bat colonies are no less healthy than others.
Nameer regretted that an unnecessary panic has spread among the people against bats. Bats have been living in close proximity to communities for ages. Most of the older open wells in the state, especially those that have been dug through laterite rock beds, commonly have bats hanging on the walls.
“It is neither possible, nor necessary to clean all these wells and remove bats,” he said. “In a crisis situation such as now we need to be careful and take precautionary measures. Let us boil water for drinking and cooking.”
Nameer consulted Paul Racey, a leading authority on bats, retired professor at the University of Aberdeen and the chair of the Bat Specialist Group of the International Union for Conservation of Nature (IUCN) over this issue. In an email to Nameer, Racey said that the disease spreads mainly by drinking palm sap that has been infected with the Nipah virus by the greater Indian fruit bat Pteropus giganteus. Preventing bats’ access to the sap collection pots has reduced the infection rate in other parts of the world. “In Bangladesh, bamboo skirts have been deployed to prevent bats from contaminating palm sap.  Do people consume palm sap, either fresh or fermented, in Kerala? This is a possible route of infection,” Racey asked in his mail.
Since palm sap toddy is a common drink in Kerala, experts advise avoiding the drink at present. This is better way to prevent the infection from spreading than harming the fruit bats.
“Culling of bats has to be totally avoided even if tests show some of the fruit bats in the region are carrying Nipah virus,” Nameer emphasized. “Earlier experience from Malayasia has shown that the virus will get more virulent if the animal is stressed and this could cause more infections.”

Ecological imbalances can also stress out bats

The virus that is present in the bats get virulent when the mammals are stressed mostly out of human-induced factors. A WHO report on Nipah Virus Infection states that “there is strong evidence that emergence of bat-related viral infections communicable to humans and animals has been attributed to the loss of natural habitats of bats.” It further adds, “As the flying fox habitat is destroyed by human activity the bats get stressed and hungry, their immune system gets weaker, their virus load goes up and a lot of virus spills out in their urine and saliva.”
According to Nameer, the bats can be stressed out due to various reasons, “It can be loss of habitat, lack of food, climate change or deforestation that can lead to the virus spilling out.”
“After the El Nino phenomenon in 1997, fires in Kalimantan and Sumatra destroyed approximately 5 millions hectares of forest. The haze badly affected the flowering and fruiting of trees in southern peninsular Malaysia. This loss of habitat and lack of food forced the fruit bats to migrate to orchard farms and that stress caused the spill out of virus,” B. Ekbal, neurosurgeon and a renowned public health activist in Kerala said.
These orchards to which the bats migrated were surrounded by number of pig farms. In Malaysia the virus was first transferred to pigs and later got transmitted to humans. More than a million pigs were culled to control the outbreak then, recalled Ekbal. The WHO report also says that 90 percent of the infected people in 1998-99 outbreak were pig farmers.

Improved public health awareness needed

Both Nameer and Ekbal emphasize the need for better public health awareness and preparedness.
https://india.mongabay.com/2018/05/30/nipah-infection-in-kerala-dont-blame-the-bats-alone-improve-public-health/

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