Oct 9, 2017 - Not an established vector of pathogens except Alkhurma haemorrhagic fever virus and Borrelia spp. from Saudi Arabia/Egypt. ⢠Could AHFV be ...
10/09/2017
Why? • Soft ticks – Ornithodoros spp. commonplace in West, East and North Africa, but not reported from Nigeria! • Sporadic reports of their presence – but not fully verified • Traditional dwellings/animal shelters with high infestation rates • Cases of febrile illness commonly presenting to healthcare professionals
Soft Ornithodoros ticks of Nigeria Cutler, S.J., Manu, J.I. and Elelu, N.
Map of northwestern Africa - Borrelia positive (red circles) or negative (blue circles) for Ornithodoros ticks in small mammal burrows.
The study: • A pilot study • Are soft tick present? • What species are they? • Could they present a risk to human health?
Trape et al. (2013) PLOS ONE 8(11): e78473. doi:10.1371/journal.pone.0078473
Are soft ticks present? • Yes! • Some areas reporting high infestation rates in traditional dwellings (Manu MPH thesis 2012)
Collection of samples – Gubio district, Borno State • Collected ticks submitted to University of Ilorin, Nigeria • Pooled by life stage • Homogenised & DNA-extracted (DNeasy)
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10/09/2017
What species?
What did we find?
• Importation regulations restrictions for ticks – extracted DNA sent, preventing morphological identification • 50 pooled samples received • Molecular confirmation • • • • • • •
16S (Black & Piesman 1994) COI (Black et al. 1997) 18S (Black et al. 1997) COI (Lv et al. 2013) Cox1 (Chitimia et al. 2010) 16S (Lv et al. 2013) ITS2 (Lv et al. 2014)
• Nothing apart from positive control – Ixodes ricinus tick • Spiking for DNA inhibitors? • Re-DNA extraction • Most assays still negative • 18S (Black et al. 1997) – non-specific weak bands • 16S (Lv et al. 2013) – bands 455 bp!!!
Used for study on O. capensis Dupraz et al. 2016
Evaluated for molecular barcoding ticks
Results continued…………
Significance?
• Amplicons from 8 samples prepared for sequencing (both directions) • 99% identity with submitted sequences for Ornithodoros savignyi
• O. savignyi “sand tampan” – veterinary significance (especially calves & lambs) causing “tampan toxicoses” and associated cardiac failure.
• Pathogen screening
• Lifespan 15-20 years with occasional feeding 5-6 years!
• 1 adult tick (or ½ an extracted salivary gland) lethal for 20g adult mouse in 20 minutes! • Predatory tick feeding on various mammals • Not an established vector of pathogens except Alkhurma haemorrhagic fever virus and Borrelia spp. from Saudi Arabia/Egypt • Could AHFV be the sought after “toxin” of O. savignyi? • Borrelia characterisation to follow
Acknowledgements & Questions • Thanks to Abdulhakeem Ahmed
