Monday, August 13, 2018

Case of the Week 506

This week's case is an arthropod removed from an elderly male living on the Pacific coast of the United States. He feels well and reports that he recently returned from safari in Tanzania.


Identification?
What infectious organisms are potentially transmitted by this arthropod?

10 comments:

Anonymous said...

Looks like a Hyalomma rufipes .

Anonymous said...

Hyalomma genus (not sure of species).
This genus can transmit Crimean-Congo hemorrhagic fever, Siberian tick typhus, and Q-fever, among others.

Eagleville said...

But isn't this a male?

Anonymous said...

This is my first encounter with this genus Hyaloma. For sure it is a male judging from the large shield, though the eyes are not clearly defined. The clefted fore coxae, adanal and subanal plates are clear cut.
The previous comment has enough info on etiology.
Florida Fan.

Old One said...

Adult male Hyalomma sp. Characteristics as well as occurrence in Tanzania are similar to H. excavatum. Some possible pathogens it may vector: Theileria annular, Babesia app. and Trypanosoma theileri

Old One said...

The Old One is a bit slow today (could it be my age?) Actually took a little more time with the descriptions.

I'm revising my ID to Hyalomma albiparmatum. Found in Savana country in Tanzania (Safari anyone). Didn't find a list of vectored pathogens for this species

Blaine Mathison said...

So far, everyone has the correct genus, Hyalomma. They are Old World ticks and are a primary vector for Crimean-Congo Hemorrhagic Fever. They pop up every now and then in the US, so US microscopists should be able to recognize them (this is the third brought to my attention since 2015!).

Members of this genus are morphologically similar, so I would hesitate to try and put a species name based on general morphology and epidemiology. From 2005-2012 or so, Apanaskevich and Horak published a series of revisions (at least 11 papers!) on the genus with keys to the species (do a Google search, most are open access if I remember, as I used them to ID the species that Bobbi and I published in 2016).

In most North American keys, Hyalomma will key to Amblyomma. When Bobbi and I published our paper on arthropods in CMR back in 2014 we included this genus for the very reason they show up in clinical labs now and then!

Unknown said...

Hyalomma sp.
Medical and importance:
A) Transmission of diseases:
1. Protozoal diseases:
Texas fever caused by Babesia bigmina
2. Rickettsial diseases:
1. Rocky Mountain spotted fever caused by Rickettsia rickettsii.
2. Q fever (Queensland fever), caused by Rickettsia burnetti.
3. Boutonneuse fever, caused by Rickettsia conori.
4. Tick bite fever, Rickettsia pijperi.
3. Viral diseases:
1- Colorado tick fever.
2- Encephalitis and equine encephalomyelitis.
4. Bacterial disease:
Tularaemia caused by Pasturella tularensis in man and rabbits.
B) Tick paralysis:
- Caused by: toxins in the saliva of the ticks.
- Manifestations: fever, rapid ascending flaccid paralysis.
- Treatment: The tick should be immediately removed by gentle traction
under few drops of anaesthetic.
C) Mechanical injury at the site of bite:
There is local inflammation, oedema and haemorrhage .The wound may
be infected and ulcerated especially if the capitulum is torn off by forc ible
traction.

Unknown said...

Hyalomma sp.
Medical and importance:
A) Transmission of diseases:
1. Protozoal diseases:
Texas fever caused by Babesia bigmina
2. Rickettsial diseases:
1. Rocky Mountain spotted fever caused by Rickettsia rickettsii.
2. Q fever (Queensland fever), caused by Rickettsia burnetti.
3. Boutonneuse fever, caused by Rickettsia conori.
4. Tick bite fever, Rickettsia pijperi.
3. Viral diseases:
1- Colorado tick fever.
2- Encephalitis and equine encephalomyelitis.
4. Bacterial disease:
Tularaemia caused by Pasturella tularensis in man and rabbits.
B) Tick paralysis:
- Caused by: toxins in the saliva of the ticks.
- Manifestations: fever, rapid ascending flaccid paralysis.
- Treatment: The tick should be immediately removed by gentle traction
under few drops of anaesthetic.
C) Mechanical injury at the site of bite:
There is local inflammation, oedema and haemorrhage .The wound may
be infected and ulcerated especially if the capitulum is torn off by forc ible
traction.

William Sears said...
This comment has been removed by the author.