Bridging Rabies to wildlife

Hi everyone!

This week I want to share with you my trip to the coastal farms. Let me show you this video on Animal Veterinary Service’s rabies vaccination exercise for dogs, where Rabies is a zoonotic disease that can spread from animals to humans and other animals.

Vaccination for dogs on floating farms. 

As we traveled to various coastal farms, I pondered why Singapore is worried about the dogs that are offshore and on seemingly isolated coastal farms. I spoke to the veterinarians and found out that dogs are mostly stray dogs and utilised as guard dogs. As mentioned by Dr. Fernandez, the dogs are mostly unsupervised and can get Rabies by swimming to watercraft from other countries (Goh, 2019).  Turns out, dogs can swim very well!

Meaning to say, free-ranging domestic dogs (FRDD) can be the perfect recipe for a disastrous spread of rabies, if not managed well. I can imagine how hard it is to manage and monitor the spread of diseases in countries that has a much greater FRDD population than Singapore.

Other than the fact that rabies extremely fatal to humans, its zoonotic potential extends to wildlife as well. Unfortunately, the endangered species of Ethiopian Wolf (Canis simensis) is not spared from the disease. In 2004 on the Bale Mountains of Ethiopia, there was an outbreak of Rabies resulting in 38 deaths of Ethiopian Wolves. The number may seem small, but their population of 300 is not huge to begin with (Randall, 2005).

“Ethiopian Wolf with rodent prey” by Magnus.

And their cause of death?

The FRDDs!

The period of outbreak coincides with the appearance FRDDs with signs of rabies around their habitat. Though how it transmits from FRDD to the dogs were not discovered, Rabies mainly transmit through bites, but can also spread through open wounds, eyes, and lips via infectious saliva (Rabies, 2020).

So what makes them “Endangered” under the IUCN Red List? The wolves are threatened by habitat loss due to agriculture. With only 197 mature Ethiopian wolves left to produce offspring, it is time to question farming methods like pastoralist grazing, where farmers move their livestock to a new land when the previous land is overgrazed. This farming method not only takes up space, but it also wipes out the habitat of the wolves’ prey, the Giant Mole Rat (Tachyoryctes macrocephalus), which is an endangered species under the IUCN Red List.  Let’s not forget the angry farmers who killed the wolves for murdering their cattle (or were the true culprits the dogs?).

Since the Ethiopian wolves are keystone species, they have direct influences on their food webs. The declining numbers would highly impact the ecosystem and cause a collapse (Keystone Species, n.d.). Moreover, changes to ecosystem cues the chance for FRDDs or any other invasive species to invade it.

Though not intentionally, the FRDDs are undeniably carriers or hotbed for pathogens. Their presence itself will always pose a threat to the whole ecosystem via transmitting diseases to wildlife.

To add on to the never-ending list of problems, there are other diseases like Canine Distemper Virus and others here that FRDDs can be transmitted to wildlife as well. Though there are rabies vaccination programs for FRDDs, in 2008, another rabies outbreak caused 75% of the Ethiopian wolves to die (Reproductive Physiology of Ethiopian wolves, n.d.).

How do we then protect wildlife species?

Reference:

Goh, T., 2019. Anti-Rabies Operation On Dogs On Coastal Farms Keeps Singapore Safe From Virus. [online] The Straits Times. Available at: <https://www.straitstimes.com/singapore/health/anti-rabies-operation-on-dogs-on-coastal-farms-keeps-singapore-safe-from-virus> [Accessed 9 October 2020].

National Geographic Society. n.d. Keystone Species. [online] Available at: <https://www.nationalgeographic.org/encyclopedia/keystone-species/> [Accessed 9 October 2020].

Randall, Dashaun & Williams, Stuart & Kuzmin, Ivan & Rupprecht, Charles & Tallents, Lucy & Tefera Ashenafi, Zelealem & Argaw, Kifle & Shiferaw, Fekadu & Knobel, Darryn & Sillero, Claudio & Laurenson, M. (2005). Rabies in Endangered Ethiopian Wolves. Emerging infectious diseases. 10. 2214-7. 10.3201/eid1012.040080.

World Health Organisation. 2020. Rabies. [online] Available at: <https://www.who.int/news-room/fact-sheets/detail/rabies> [Accessed 9 October 2020].

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