5 September 2018

Second tick species found to cause meat allergy

Immunology Research

The second tick species in Australia to cause mammalian meat allergies in humans has been identified by the same researcher who first discovered the phenomenon over a decade ago.

Australian allergist Associate Professor Sheryl van Nunen first made the connection between bites from the tick species Ixodes holocyclus and mammalian meat allergies in 2007.

Her research team has now identified a second tick species, Ixodes (Endopalpiger) australiensis, as a novel culprit.

This tick species is endemic to Western Australia. It was not known to bite humans until very recently. Ixodes (Endopalpiger) australiensis bites were found to aggravate a pre-existing mammalian meat allergy in a 52-year old man, according to the case report.

The man was first bitten by an unidentified tick in 2013 in the coastal town of Denmark in Western Australia. Three months after the first bite, the man started having allergic reactions to meat.

Eating lamb chops or beef mince caused anaphylaxis on several occasions and he eventually  stopped eating mammalian meat altogether.

The man was bitten three times in late 2017 by ticks that were identified by researchers as Ixodes (Endopalpiger) australiensis.

A measurement of the antibodies in the man’s blood showed that the bites from this tick species had a “recharging effect”, making the allergy worse, the researchers said.

Since the discovery of tick-induced mammalian meat allergies in Australia, this condition has been identified in 17 countries on all six continents where humans are bitten by ticks.

Asia Pacific Allergy 2018, July