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Beyond poaching: How rhino dung offers clues on health and natural death (India)

By October 19, 2020Science and technology

Indian Rhino in Kaziranga National Park. Photo: Wikimedia Commons.

Tora Agarwala, The New Indian Express | October 15, 2020

Read the original story here.

In conservation efforts for the greater one-horned rhinoceros population in India, the latest strategy is an examination of rhino dung to understand health issues of the animal. Since 2017, the Rhino Task Force of Assam and World Wildlife Fund India (WWF India) have been undertaking steps to study pathogens found in fresh rhino dung samples in Assam, Uttar Pradesh, and West Bengal. WWF India has recently published preliminary reports — ‘Prevalence of Endoparasitic Infections in Free-Ranging Greater One-Horned Rhinoceros’ — for Assam and West Bengal.

“The main objective of this initiative is to start a systematic disease investigation process for the rhino,” said Dr Parikshit Kakati, Senior Program Officer Veterinary, WWF India, who is among the researchers.

Why is Such a Project Important?

While poaching is believed to be the main cause of death in rhinos, rhinos also die of natural causes which have not been studied in great detail. “When a rhino carcass is found, the first question asked is: ‘Is the horn intact?’ If it is not, it means it was poached. Otherwise, it is considered a ‘natural’ death. There may be multiple reasons for a natural death but it is rarely investigated thoroughly,” said Bibhab K Talukdar, chair, Asian Rhino Specialist Group of International Union for Conservation of Nature/Species Survival Commission; Asia coordinator, International Rhino Foundation; and CEO and secretary general of the NGO Aaranyak.

According to the researchers, habitat degradation can lead to an increased exposure to pathogens. “Due to increasing livestock pressure on protected areas, there is a possible threat of pathogens getting transferred from domestic animals to wild animals.” Talukdar said: “Diseases linked to habitat degradation are invisible causes of rhino death. For example, a rhino might not get its regular feed, compelling it to instead feed on weeds etc. This may cause problem in their health.”

How is the Project being Carried Out?

Till date, there has been no systematic study on the prevalence of disease-causing parasites and diseases caused by these in the rhino population in India. “In order to address this knowledge gap, the present study is a part of a series that involves screening of pathogens through a non-invasive method of dung sample analysis,” stated the report.

Samples were collected from UP’s Dudhwa National Park; West Bengal’s Jaldapara National Park and Gorumara Park; and Assam’s Rajiv Gandhi Orang National Park, Pobitora Wildlife Sanctuary, Manas National Park, and Kaziranga National Park. The researchers collected the samples fresh (not older than from the previous night), gave them unique IDs and sent them to the Department of Parasitology in the College of Veterinary Science, Assam Agricultural University, Guwahati.

What Are the Findings?

From the samples from Assam and West Bengal, the study concluded that parasites from four genera were present in an estimated 68% of India’s rhino population. The overall prevalence of endoparasites was 58.57% in Assam and 88.46% in West Bengal; results from UP are pending.The endoparasites in Assam belonged to four genera: Amphistome spp, Strongyle spp, Bivitellobilharzia nairii and Spirurid spp, while West Bengal reported the prevalence of only Strongyle spp, Assam reported all four. “When comparing this [Bengal] study with that conducted in Assam, we find that the rhino population in West Bengal has a higher prevalence rate of infection, but the occurrence of different parasites were higher in Assam,” stated the report.

“These pathogens are quite common and not very alarming,” said Dr Kakati. Until now, the studies just reveal that the pathogens exist. “Our second stage of investigation will determine how harmful they are.” He said the study was still at a preliminary stage but “extremely helpful”. “We now have a baseline for how often and what types of parasites are found in the wild rhino population —a key step in determining the harmful effects the parasites have on their rhino hosts,” he said.

The team will now branch out to examine bacterial fauna and viral agents, as well as a hormonal study.