By Sharon Atieno
Though bats have been linked to various diseases globally including Ebola, Marburg, Nipah, Hendra, Middle East respiratory coronavirus (MERS-CoV) and COVID-19 among others, human interference in most instances have contributed significantly to these transmissions.
Speaking during a Media for Environment, Science, Health and Agriculture (MESHA) biodiversity café in Nairobi, Kenya, Bernard Agwanda, research scientist and curator, National Museums of Kenya called for the need to avoid such interferences to prevent the occurrence of spillover events (spread of virus from the bats to human beings).
He observed that bats have many viruses but very few are transmitted to human beings. “Bush meat harvesting of bats or butchering bats or handling them, particularly when they look sick is one way of getting the virus out,” Agwanda said.
“Interacting with the bats directly is the cause, whether you are butchering to eat or sampling them or you are unknowingly touching where they are. That’s how the transmission occurs.”
He observed that some bat-borne viruses such as the corona, paramyxo and Ebola groups can be transmitted via urine or faeces (droppings). The transmission can also occur through their urine because some viruses go all the way to the kidneys and the kidneys are where the urine is produced as a byproduct.
One can be infected through the feaces. Also when eating bats, one can interact with the blood or fluid on the bat and if the blood or fluid is infected, the virus can be transmitted from the bat to the person.
“There are some viruses we have found in bats which nobody has reported to cause any disease, but that doesn’t mean they don’t cause diseases neither does it mean that they cause diseases. But there are viruses that we know cause diseases and we have found them in a particular bat in a particular location,” Agwanda said.
One of the viruses which have not been reported to cause diseases is the Shimoni bat virus, a type of rabies virus, found in the Striped Leaf-nosed bats (formerly known as Hipposideros) around Shimoni area in Kenya’s Coastal region.
Contrastingly, the Lagos bat virus was found in the Straw-coloured fruit bat species in Maseno, a region in the Western part of Kenya. The virus has led to fatal cases in Zimbabwe and Nigeria but no case has been reported in Kenya.
“Unlike Shimoni which we don’t know, this one we know it can cause problems but we found it in bats but didn’t find it in people,” he reiterated, adding that this virus can infect humans directly (touching dead bats) or via cats or dogs that have feasted on the infected dead bat. The virus had been isolated from a domestic cat in Zimbabwe in 1986, and twice from dogs in Ethiopia in 1989 and 1990.
Agwanda observed that every species in the ecosystem including bats have a role to play. Bats pollinate many plant species, and so maintain essential genetic diversity among plants depending on them for pollen transfer. Some plants such as Baobab (the parent tree from which Mabuyu fruits come) depend on bat pollination since their flowers only open at night when bees and birds are asleep.
Also, he noted that many fruit bats are practically environment engineers that seed cleared forest patches in the landscape through seed dispersal. This is a critical ecosystem function enabling many plant species to avoid incest and associated lethal genetic bottlenecks. More importantly, they broadcast seeds in cleared forest patches and so contribute to re-afforestation.
Additionally, they help in pests and parasite management as some feed on mosquitoes, beetles, moths and leafhoppers among others which would be a bother to human beings in terms of food security and the spread of diseases.
For human beings and bats and other wildlife to co-exist peacefully and thus reduce the risk of viruses jumping from them to human beings, he recommended the need to avoid any physical contact with them including touching, hugging and kissing them as this creates a bridge for the virus to move from them to human beings.
Also, people should consult experts in cases where an animal is enforcing its interaction on them, for instance, a bat can be in the house and it doesn’t seem to want to fly out or it has dropped down or struggling to fly. This is because the virus may make the animal sick and “mad” causing it to behave irregularly.
Additionally, caution is called for in interacting with bats sick or dead. Safe disposal by burying or burning is highly recommended.
Communities must avoid disturbing bats like going to the caves and lighting fire or bulbs that would force bats out. Disturbing and disrupting bats from their natural roosts is the best way to cause a human pandemic and crop disease pandemic, he said.
At the government level, there must be certain policies and guidelines on how to appreciate nature and give incentives to people who do their best to protect nature, he said, adding that unless this is done, it will be difficult for the government to protect wildlife outside protected areas.