By Jeffrey Wiegert and Guilherme G. Verocai et.al
Introduction – The NWS Threat to Swine Producers
The New World screwworm (NWS), Cochliomyia hominivorax, is a parasitic fly whose larvae feed on living tissues of warm-blooded animals. Larval infestations (myiasis) can occur in any broken or damaged skin and cause rapidly progressing, painful wounds that can lead to serious injury or death.
In the 1970s, the NWS was successfully eradicated from the United States. This was done through the mass release of sterile male flies (sterile insect technique).
Producers can take several steps to stay ahead of the pest as New World screwworm emerges in U.S. livestock production.
Various livestock species, including pigs, are at risk of infestation in endemic areas. Data from the current outbreak in Mexico shows that pigs are the third most affected species, after cattle and dogs. Swine kept in both outdoor and indoor production systems may be at risk.
Myiasis due to NWS can impact general health and well-being of pigs and is potentially fatal depending on anatomic location, severity of infestation, and timing from diagnosis to proper treatment.
Monitoring and Surveillance
Any break in the skin should be considered a potential risk site for myiasis when adult flies are active in an area. Therefore, swine should be inspected daily for the presence of potential wounds and clinical signs, at least until the wound site heals fully.
Signs of a NWS infestation on animals can include, but are not limited to:
- Wounds with abnormal appearance that progressively worsen
- Wounds with the smell of rotting tissue
- Head shaking and biting, licking, or rubbing at wounds
- Irritated or depressed behavior, including loss of appetite
- Visible fly larvae in wounds
- Wounds with bloody discharge
Source : tamu.edu