External parasites and West Nile Virus

Lice

Avian lice are usually not a serious concern. Healthy birds groom them off and resist an overabundance; ill birds become infested. Most lice feed on feathers and skin debris. So: bird lice cannot kill a healthy raptor, which is the exam's point. A new passage bird with lice crawling on its feathers is treated with two percent Sevin dust.

Hippoboscids

Flat, fast-moving blood-sucking flies, and these are dangerous. Large numbers cause anaemia, and they are known to transmit haemoproteus, an intracellular parasite of red blood cells, and West Nile Virus.

Maggots

As soon as possible after taking a nestling, inspect its ears for maggots (myiasis). The parasite is especially common in Cooper's Hawks in the southern part of their range, from the screw-worm fly. It is occasionally fatal to wild young but easy to clear from the ears of a bird a falconer has taken: a few drops of saline in the ears will cause them to leave.

West Nile Virus

Acquired mostly through the bite of an infected mosquito, with concern that hippoboscid flies and other ectoparasites may also transmit it. Infected birds shed the virus in oral and other secretions.

In raptors WNV causes severe infection of many organs, including the brain, heart, kidneys, intestines, feather follicles and eyes. The clinical signs the exam wants are weakness, seizures, anaemia and blindness. Left untreated it is rapidly fatal.