| Summary: | Thesis (MSc)--University of Stellenbosch, 2005. === ENGLISH ABSTRACT: The African penguin, which occurs along the south-eastern and south-western shores of
South-Africa and Namibia, has experienced a severe reduction in population numbers
due to guano and egg collection in the first half of the 19th century, and oil pollution in
the second half of the 19th century as a result of oil tankers rounding the Cape of Good
Hope. The population would have been reduced by a further 19% had it not been for
the rehabilitation of penguins at the South African National Council for the Conservation
of Coastal Birds (SANCCOB) facility. Although this has been very successful,
mortalities as a result of avian malaria infection have considerably reduced the
efficiency of rehabilitation. In an effort to assess the role of immunity against malaria in
combating the disease, an enzyme-linked immunosorbent assay (ELISA) for the
detection of antibody levels to avian malaria was developed. The ELISA was used to
detect antibody levels to avian malaria of penguins on entry and during rehabilitation
from October 2001 to January 2003.
The aim of this study was to continue the determination of antibody levels to avian
malaria of penguins entering the SANCCOB facility, in order to allow an evaluation of
the antibody levels to avian malaria for two full calendar years. This investigation was
combined with a polymerase chain reaction (PCR)-based method, capable of detecting
any Plasmodium species in penguin serum. These two methods were also used to
investigate avian malaria in several breeding colonies in order to assess the role avian
malaria may play in the survival of the African penguin in the wild.
Results indicated that the ability of penguins to produce anti-Plasmodium antibodies
was not influenced by oiling and that infection with malaria was not due to
recrudescence but rather due to infection via mosquitoes. This indicated a possible role
of the SANCCOB facility in exposing the penguins to avian malaria. However a large
number of penguins arrived at the facility previously infected with malaria, indicating that
malaria was present in the breeding colonies. Investigations in the breeding colonies
revealed extremely high avian malaria prevalence even though no sick birds or
mortalities were observed. This raised the question whether different types of malaria
are responsible for infection in the SANCCOB facility and breeding colonies. === AFRIKAANSE OPSOMMING: Die Afrika Pikkewyn kom langs die suid-oostelike en suid-westelike kus van Suid Afrika
en Namibië voor. In die afgelope eeu het hierdie spesie ‘n geweldige afname in
populasie getalle ondervind. Dit was hoofsaaklik die gevolg van die versameling van
guano en pikkewyneiers in die eerste helfte van die 19de eeu en oliebesoedeling in die
tweede helfde van die 19de eeu. Die “South African Foundation for Conservation of
Coastal Birds” (SANCCOB) is ‘n seevoëlreddings- en rehabilitasiesentrum vir siek,
beseerde en ge-oliede pikkewyne. Dit word geskat dat die Afrika Pikkewyn populasie
met ‘n verdere 19% sou afgeneem het as dit nie vir die rehabilitasie by die SANCCOB
sentrum was nie. Hierdie sentrum het egter aansienlike vrektes in die somer as gevolg
van voëlmalaria, wat sodoende die effektiwiteit van die rehabilitasie verlaag. In ‘n
poging om die rol van immuniteit teen malaria te bepaal is ‘n “enzyme-linked
immunosorbent assay” (ELISA) ontwikkel vir die bepaling van antiliggaam vlakke teen
malaria. Hierdie ELISA is gebruik vir die bepaling van die anti-Plasmodium antiliggaam
vlakke van die pikkewyne by aankoms en ten tye van rehabilitasie by SANCCOB vanaf
Oktober 2001 to Januarie 2003.
Die doel van hierdie studie was eerstens om hierdie ELISA bepalings voort te sit om
sodoende antiliggaam vlakke teen malaria oor twee kalender jare te kan evalueer.
Hierdie ondersoek was gekombineer met ‘n polimerase ketting reaksie (PCR) metode,
wat enige Plasmodium spesie in pikkewynserum sou kon opspoor. Hierdie twee
metodes is ook gebruik vir ondersoeke in sommige broeikolonies, met die doel om te
bepaal watter rol voëlmalaria in die oorlewing van die Afrika pikkewyn in die natuur
speel.
Resultate het getoon dat olie nie die vermoë van die pikkewyn beïnvloed om anti-
Plasmodium antiliggame te vervaardig nie en dat malaria infeksie hoofsaaklik deur
muskiete veroosaak word en nie deur heruitbraak van ‘n bestaande infeksie nie. Dit dui
egter daarop dat pikkewyne blootgestel word aan voëlmalaria by die SANCCOB
sentrum. Daar is ook gevind dat ‘n groot aantal pikkewyne met malaria infeksies by die
sentrum opgedaag het wat dui op die voorkoms van malaria in die broeikolonies.
Ondersoeke in die broeikolonies het ‘n besonder hoë voorkoms van malaria onthul.
Geen vrektes of siek pikkewyne is in die broeikolonies waargeneem nie, wat moontlik
kan beteken dat pikkewyne by SANCCOB met ‘n ander tipe malaria geïnfekteer word
as in die broeikolonies.
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