Superbug that poses grave threat found in Delhis strays

Tuesday Jul 11, 2023

The first live culture of the superbug "Candida auris" - an emerging fungus that presents a serious global health threat and is resistant to most anti-fungal medicines - has been discovered in the ear canals of Delhi's stray dogs. It has been isolated .

NEW DELHI: The first live culture of the superbug "Candida auris" - an emerging fungus that presents a serious global health threat and is resistant to most anti-fungal medicines - has been discovered in the ear canals of Delhi's stray dogs. It has been isolated .

While there is no direct evidence to show if the fungus infection is transmittable from dogs to humans, the whole-genome sequences of strains from dogs showed very close relationships with a few strains from humans in India and the larger South Asian region.

The US Centers for Disease Control and Prevention (CDC) had earlier alerted and expressed concern about the emerging fungus and rated it as an "urgent threat". It has been classified as one of the world's four "critical priority" fungal pathogens by the World Health Organization (WHO).

According to the researchers from Delhi university and McMaster University, Canada, though their report highlights the isolation of C.auris from the animal source, the routes of transmission of this yeast to dogs and the clinical significance of transmission between dogs and humans remains to be investigated.

A study published online in the 'Journal of Fungi', researchers tested skin and ear swab samples from 87 dogs collected from North Delhi's public referral hospital cum shelter. They found evidence of C. auris within the ear canals of four (4.5%) of the 87 dogs with chronic skin infections.

Of these total dogs, 52 (60%) were stray dogs who were admitted to the intensive care unit (ICU) with severe skin lesions due to chronic skin diseases. Among these, eight had otitis externa (causes inflammation, redness and swelling of the external ear canal) with clinical signs of ear infection - erythema, oedema, erosion and exudate in the affected ear. The remaining 44 dogs exhibited skin infections. 35 (40%) were household pets attending the outpatient services for minor ailments of the gastrointestinal and urinary tracts.

While contacted via email, Jianping Xu, a lead author of the paper and professor at McMaster's department of biology, said, "At present, we don't have direct evidence for the directionality of strain spread from dogs to other animals or humans. However, based on whole-genome sequences, several strains from dogs showed very close relationships with a few strains from humans in India/South Asia. This result is consistent with the recent shared ancestry of strains from dogs and humans and suggests the possibility of spread among different host animals."

He added that more extensive surveys are needed in order to determine the significance of dogs as a reservoir for this pathogen and the extent of transmission between dogs and other organisms.

Researchers emphasised that, in the present study, since the yeast was found within the ear canal of the dogs versus exposed skin, shedding in the immediate environment was reduced, containing the spread of infection. However, in the case of humans infected with C auris, inanimate objects in the environment are readily contaminated by the shedding of skin scales.

Healthworld.com