Human-type and pig-type Ascaris hybrids found in pigs

Area of Science:

• Parasitology
• Molecular Biology
• Genetics

Background:

• The relationship between Ascaris lumbricoides (human roundworm) and Ascaris suum (pig roundworm) is complex due to the discovery of hybrids.
• Understanding Ascaris species identification and host specificity is crucial for controlling ascariasis.

Purpose of the Study:

• To investigate the genetic makeup and host-infecting capabilities of Ascaris hybrids.
• To compare the effectiveness of different molecular methods for identifying Ascaris species and hybrids.

Main Methods:

• Analysis of 48 human and 48 pig Ascaris specimens.
• Application of microsatellite markers with Bayesian clustering.
• Utilisation of PCR-RFLP of the nuclear internal transcribed spacer (ITS) region.

Main Results:

• Two molecular methods yielded inconsistent results for hybrid identification.
• Hybrid Ascaris, identified by both methods, were confirmed to infect pigs.
• PCR-RFLP of ITS alone was deemed unsuitable for differentiating human-type and pig-type Ascaris hybrids.
• Microsatellite markers with Bayesian analysis demonstrated the highest reliability.

Conclusions:

• Hybrid Ascaris individuals can infect both humans and pigs, challenging traditional host specificity assumptions.
• The findings necessitate a re-evaluation of current ascariasis control strategies.
• Multiple molecular markers, such as SSRs, combined with robust analytical approaches are recommended for accurate Ascaris hybrid identification.