Preventing spread of infectious agents or parasites are fundamental in reducing threats to biodiversity. Responses that address disease agents/parasites directly are becoming more pertinent as increasing number of globally threatened species are being affected by disease.
Such responses include vaccination against morbillivirus that affected critically endangered Mediterranean monk seal, Monanhus monachus (Osterhaus et al., 1998), removal of affected individuals, other infected hosts/reservoirs, reduction of connectivity between affected and healthy populations, provision of medicine and translocation of healthy individuals to captivity or to non-affected places.
Pomarea dimidiate is endemic to pacific island of Rarotonga. Although common in mid 1800s, it subsequently declined rapidly and following collection of a few specimens in early 1900s, it was not recorded until 1973. In 1983, 21 birds were discovered. A survey in 1987 estimated the populations with 38 individuals.
Image Source: curezone.org
ADVERTISEMENTS:
A recovery plan was prepared in 1988 with implementation began later the same year. Intensive control of predators (Rattus rattus) reduced adult mortality from 24% to 9% with nesting success increasing from 15% to 63% (Robertson et al., 1994).
By 2000, the populations had reached 221 individuals and in 2001-2003, 30 young birds were transferred to rat free island of Atiu (200 Km northeast of Rarotonga) in an apparently successful attempt to establish second insurance populations.
In 1904, a shipment of nursery stock from China brought a fungal blight to United States. Within 40 years, American chestnut had disappeared from its native range. Efforts are now underway to transfer blight resistant genes into few remaining American chestnuts that weren’t affected by the fungus or to find biological controls for fungus.
ADVERTISEMENTS:
Whirling disease caused by Myxobolus cerebralis is decimating trout populations in many western states. The parasite is believed to reach into United Slates in 1956 in a shipment of frozen fish.