Update: New World Screwworm in Florida - Dr. Michael Short, State Veterinarian/Director, Division of Animal Industry, Florida Department of Agriculture and Consumer Services, from the 2017 NIAA Annual Conference, U.S. Animal Agriculture's Future Role In World Food Production - Obstacles & Opportunities, April 4 - 6, Columbus, OH, USA. More presentations at http://www.trufflemedia.com/agmedia/conference/2017_niaa_us_animal_ag_future_role_world_food_production

1. Dr. Mike Short
Division of Animal Industry

2. Cochliomyia hominivorax
 Only insect known to
consume living tissue
of warm- blooded
animals
 Currently endemic in
South America and
some Caribbean
Islands, including Cuba

3.  Female flies only mate once
 Female flies attracted to blood or odors
 Eggs laid near wound
 First instar visible in ~3 days – discharge and
odor
 Second instar and third instar ~4-12 days
 Pupae drops from wound – burrows into ground
 Hatch depends on environmental conditions
○ Mature in 3-5 days to mate

5.  1852: First reports of New World
Screwworm
 1958: Development of sterile male
technique (SIT)
 1966: U.S. free of Screwworm
 1991: Mexico declared free
 2003: Sterile fly facility
established in Panama

6.  Sterile Insect Technique (SIT) is the only
effective strategy for eliminating established
NWS fly populations.
 Affected areas are inundated with sterile male
NWS flies.
 Target is 10:1 ratio of sterile to wild type
 The females only mate once in their lifetime, so
every female that mates with a sterile male has
no offspring.

7.  Larvae visible in wound by 3 days
 May be hundreds present
 Bloody discharge
 Foul-smelling odor
 Depression
 Off feed
 Separation
 Attempt to control discomfort
 Can be fatal if not treated

8.  Removal of larvae
 Debridement, if necessary
 Good hygiene
 Topical Insecticides
 Anti-parasitic drugs
 Avermectins-Injectable, topical
 Capstar (nitenpyram)
 others

9.  Contact from biologist at National Key Deer
Refuge (September 29, 2016)
 Severe fly infestation with aggressive myiasis
 Over 20 deer had been euthanized for myiasis
 Big Pine Key & No Name Key
 Original case – July 4, 2016 in deer
 motor vehicle related injury
 Larvae sample shipped to NVSL
 high priority investigation

12.  Administered by US Fish and Wildlife Service
 Endangered Key Deer reside on multiple keys
 ~1000 deer; residing on ~20 keys
 Reside on refuge and freely wander into
urban/residential areas
 Significant urban/wildlife interface
 2016 fawn crop was good and survival was good
 Fawning season (Mid March – Late May)

16.  Deaths (July – September 2016)
 July = 4
 August = 7
 September = 20
 Male = 25
 Female = 5
 Unknown = 1 0
1
2
3
4
Female
Male
Unknown
Key Deer bucks had started rut by August

17.  Unified Command – USDA, FDACS, Monroe
County Emergency Operations
 Joint IMT deployed to Florida Keys
 Multiagency
 Declaration of Agricultural Emergency
○ Commissioner of Agriculture and Consumer Services
 Official State Quarantine Area
 Controlled Animal Movement from Monroe
County
○ Key Largo Interdiction Station

18.  USDA APHIS Veterinary Services
 FDACS
 Monroe County EOC
 US Fish Wildlife Services
 USDA APHIS Wildlife Services
 Florida Fish & Wildlife Commission
 USDA ARS
 USDA IS
 COPEG – Panama Barrier Eradication Program

19.  Prevent infestation from spreading to new areas
 Disease surveillance to identify additional cases
 Fly-trapping to determine the extent of infestation
 Elimination of New World screwworm flies from
the affected Keys
 Sterile fly release twice weekly at several locations
○ Approximately 7.2 million flies per week
 Treat Key Deer

20. Yellow Border = Surveillance Zone, Red Border = Infested Zone, Orange Border = Barrier
Zone
As of 01/01/2017, barrier zone changed to Northern Surveillance Zone

24.  Baiting flies with liver, capturing adult flies
 Entomologist evaluates
 Wild type NWS Flies
 Sterile NWS Flies (release flies)
 27 Keys in the NWS Infested Zone
 3 Keys in the NWS Barrier Zone
 7 Keys in the NWS Northern Surveillance
Zone
 6 Keys in the NWS Southern Surveillance
Zone

26.  Euthanasia and Disposal of infested Key
Deer
 Treatment of Key Deer (>15,000 doses)
 Oral preventative
○ Hand feeding
 Topical Systemic preventative treatments
○ Treatment Stations
 Immobilize and treat of clinical cases

28. Key Deer Treatments

31.  Over 160 million flies
released to date
 Shipments from
Panama on Monday &
Thursday
 Releases on Tuesday
and Friday
 29 release sites on 14
keys
 Releases on keys with
infestation, and
 Releases (4) in barrier
zone (ended on 12/26/16)

33. Red border = Infested Zone; Orange border = Barrier Zone

34.  Stray Dog found near Everglades National
Park entrance with myiasis
 Picked up by Miami Dade Animal Services
 Confirmed positive for NWS – 01/06/2017
 Single male
NWS fly capture
in extensive
liver assessment
trapping

35.  Extensive
outreach
 Active
Surveillance
 Fly
Assessments
 Sheep and Goat newborn navel exams
 Sterile Fly Release in an abundance of
caution

36.  Confirmed positive NWS cases - 17
 6 domestic animal cases and 11 wildlife cases
 16 cases from infested zone (on 6 keys)
○ Last case confirmed Key Deer 01/10/2017
 Confirmed negative investigations - 53
 45 domestic animal cases and 8 wildlife cases
 9 cases in Infested Zone and 39 from mainland
 Also, 1 AL case, 2 GA case and 2 LA cases

37. 0
10
20
30
40
50
60
NWS Confirmed and Presumptive Cases
Key Deer Cases Confirmed Wildlife (non Key Deer)
Presumptive Domestic Animal Cases Confirmed Domestic Animal Cases
Index Case 09/29/2017 SIT began 10/11/2017 Deer Treatment began 10/26/2017

38.  Closed Interdiction Station on March 18
 Stopped releasing sterile flies in Homestead are
on March 24
 Closed ICP on March 25
 Releasing sterile flies in Lower Keys until April 24
 Stopped deer treatment stations on March 16
 USFWS stop hand treatments of deer on April 10
 Stopped active surveillance on March 15
 Continuing close surveillance of Key Deer
 Continuing outreach and education

39. Dr. Mike Short
Florida Department of Agriculture
and Consumer Services