First report of cystic echinococcosis in rhinos: A fertile infection of Echinococcus equinus in a Southern white rhinoceros (Ceratotherium simum simum) of Kruger National Park, South Africa

Abstract

Despite being a parasitic disease known since ancient times, some epidemiological aspects of cystic echinococcosis (CE) remain unclear. Many studies describe its prevalence and genotyping in populations of domestic animals and livestock, but data regarding wildlife are often scarce and incomplete. The available literature suggests that CE has never been reported in African rhinos. Considering the fragile conservation status of these species due to continued poaching, this study tries to clarify some neglected epidemiological aspects. In February 2020, an adult female of the Southern white rhinoceros, Ceratotherium simum simum (Burchell, 1817), was killed by poachers. The subsequent necropsy performed by the state veterinary team revealed the presence of seven cysts within the pulmonary tissue (four cysts in the right medio-caudal lobe and three cysts in the left medio-caudal lobe) with a diameter of between 1.5 and 2.3 cm. Given the state of decomposition of the carcass, only two of these were suitable for microscopic examination. Specimens were examined under 10x and 40x microscopic magnification for the confirmation of fertility of the cysts, based on the presence of numerous protoscoleces in different stages of maturation. A histopathological examination was also performed to describe the relationship between parasite and host tissue reaction. Cyst samples were subjected to PCR. The primers successfully amplified the expected fragments of the cox-1 and the nad-1 gene from the isolated genomic DNA, revealing high sequence identity with published sequences of Echinococcus equinus Williams & Sweatman, 1963 isolate G4 and E. equinus isolate SLG5-G4.

Cystic echinococcosis in donkeys in eastern Africa

“…This is in clear contrast to the situation in southern Africa, where E. equinus is obviously common in plains zebras and wild carnivores in northern Namibia (Wassermann et al ., 2015 ), was reported from a mountain zebra in ‘South West Africa’ (Kumaratilake et al ., 1986 ), and where reports of 60% ‘incidence’ (sic) and fertility of cysts in plains zebra of Kruger National Park in South Africa also suggest the frequent presence of E. equinus there (Young, 1975 a , 1975 b ). The latter is supported by a recent report of fertile cysts of E. equinus in a white rhino from Kruger National Park, RSA (Zaffarano et al ., 2021 ). There are no reports of E. equinus in donkeys, horses or domestic dogs from southern Africa.…”

“…In Africa, E. equinus is known to infect donkeys north of the Sahara at considerable frequency (Azlaf and Dakkak, 2006 ; Haridy et al ., 2008 ; Taha, 2012 ; Aboelhadid et al ., 2013 ; Boufana et al ., 2014 ; Lahmar et al ., 2014 ; Mahdy et al ., 2014 a , 2014 b ; Barghash et al ., 2017 ; Desouky et al ., 2017 ), and in southern Africa, it has been reported from horses, zebras and rhinos (Kumaratilake et al ., 1986 ; Wassermann et al ., 2015 ; Romig et al ., 2017 ; Zaffarano et al ., 2021 ). However, there are no records from the west, central and east of the continent.…”

High species diversity of Echinococcus spp. in wild mammals of Namibia

“…involving domestic dogs and livestock are well described and are assumed to be the main drivers of human infection with cystic echinococcosis (CE) ( Romig et al, 2011 ). Besides this, eight species of wild carnivores were found to harbour Echinococcus worms, and close to 25 species (depending on the species concept) of mammals, mainly ungulates, are known to be intermediate hosts ( Boufana et al, 2015 ; Hüttner and Romig, 2009 ; Jenkins and Macpherson, 2003 ; Zaffarano et al, 2021 ). As most records from wildlife date back to the pre-molecular era, the identity of the Echinococcus species in African wildlife is mostly lacking ( Deplazes et al, 2017 ; Hüttner and Romig, 2009 ; Macpherson et al, 1983 ; Romig et al, 2017 ).…”

“…Molecular identification of Echinococcus spp. in South Africa is restricted to cysts from 32 human patients ( E. canadensis G6/7, E. granulosus s.s. and E. ortleppi ), one cow ( E. ortleppi ), one white rhinoceros ( Ceratotherium simum ) ( E. equinus ), three hippopotamus ( E. felidis ) and worms from one lion ( E. felidis ) ( Halajian et al, 2017 ; Hüttner et al, 2008 ; Mogoye et al, 2013 ; Zaffarano et al, 2021 ).…”

A novel intermediate host for Taenia serialis (Gervais, 1847): The European roe deer (Capreolus capreolus L. 1758) from the Monti Sibillini National Park (MSNP), Italy

“…Sporadic cases of metacestodoses in uncommon intermediate hosts have been reported and often they seem to be attributable to epiphenomenon due to a high parasite pressure, where the intermediate host usually behaves as dead-end host ( Poglayen et al, 2016 ; Zaffarano et al, 2021 ). Other causes implied in an enlargement of the host range could be associated to environmental factors and to the abundance of host species able to be parasitized ( Walker et al, 2017 ).…”