The limitations change depending on the species:
APHIS forbids the entry of swine and ruminants from Costa Rica, including cattle, sheep, and goats.
APHIS will allow the importation of pet dogs, hedgehogs, tenrecs, elephants, rhinos, and tapirs from Costa Rica as long as they are accompanied by a certificate signed by a full-time salaried veterinary official of the region of origin stating that the animal was examined for screwworm within five days prior to shipment to the United States and is either free from screwworm or was discovered to be infected with screwworm, was quarantined, and was treated
Horses coming into the country straight from Costa Rica are required to follow the approved import screwworm protocol, which calls for a minimum 7-day quarantine period. APHIS will allow horses to finish a 3-day quarantine upon arrival if they spent at least 7 days in a nation without screwworms before being transferred to the US.
The shipment must be accompanied by health certificates from every region visited in the 60 days preceding to export. Additionally, a screwworm certification that states the horse was inspected and proven clear of screwworm after being in the nation for at least 7 days must be submitted. This certification must be supported by a licensed veterinarian from the exporting country.
What is the New World Screwworm?
The New World screwworm fly (Cochliomyia hominivorax), which feeds on the flesh of living mammals and, less frequently, birds, is the source of the New World screwworm disease, according to APHIS. The New World screwworm is thought to cost the American livestock industry $20 million on average per year.