Wednesday, April 13, 2022

Case of the Week 679

Here is a beautiful tick for you all to identify from Florida Fan - something that is very timely for this season! You can use this TICK KEY to help you get it into the correct genus. What is the potential significance of this finding?


Eagleville said...

? Haemaphysalis sp.

Horopito said...

Appears to be Haemaphysalis -- and very likely the newly invasive Asian longhorned tick.

For further information (and a key to speciation within the genus), see
Egizi AM et al. A pictorial key to differentiate the recently detected exotic Haemaphysalis longicornis Neumann, 1901 (Acari, Ixodidae) from native congeners in North America. Zookeys. 2019;(818):117-128.
Full text:

"Until recently, only two haemaphysaline species, Haemaphysalis chordeilis and Haemaphysalis leporispalustris, were known to occur in the United States, and neither was considered to be of significant medical or veterinary importance. In 2017–2018 established populations of the Asian longhorned tick, Haemaphysalis longicornis Neumann, were detected in the eastern US for the first time."

"Haemaphysalis longicornis has the potential to be a significant threat to human and animal health, and the urgent need to determine the full extent of its distribution and host range requires availability of a straightforward and practical guide to differentiate it from native species. We created a pictorial dichotomous key to all stages of Haemaphysalis spp. known to occur in North America with scanning electron photomicrographs of all H. longicornis life stages, including rarely seen males, to aid researchers in differentiating these species."

Sam said...

I don't have much experience with ectoparasites, but I based on what I can see, I would guess Rhipicephalus sanguineus. It is the vector for Rickettsia rickettsii, the aetiological agent of Rocky Mountain Spotted Fever.

Blaine Mathison said...

Haemaphysalis yes, but we also have native species in the US, including the rabbit tick. H. leporispalustris. None of them spread disease-causing agents to humans in the US.

Note the lateral extensions of the palps, not to be confused with the angulate basis capituli of Rhipicephalus. This genus also lacks eyes, which we usually only associate with Ixodes among the ticks that regularly bite people in the US. There should be festoons, too, but I am having trouble appreciating them in this image.