Professor Peter O'Donoghue


School of Chemistry and Molecular Biosciences
Faculty of Science
+61 7 336 52584


Clinical protozoology.

My area of specialization is clinical protozoology and I practice essentially as a diagnostician; i.e. I detect and study unicellular protozoan parasites infecting vertebrate hosts. I have long been fascinated by their extreme biodiversity as manifest by considerable variation in their structure, function and mode of existence. The prevailing theme of my research is to discover and describe protozoan species in Australian animals. My studies are deliberately parochial as our continent is simply the last great unexplored bastion for micro-fauna. Little is known about protozoa in the gut, blood and tissues of native mammals, birds, reptiles and fish. I seek to define the morphology, biology, historical zoogeography and pathogenicity of endemic protozoan species. I want to know their identity, origins and interactions with their hosts. Despite the diversity of hosts sampled, I confine my studies to four main protozoan assemblages: flagellates, amoebae, ciliates and sporozoa. I have detected a high degree of endemicity of these groups in Australian vertebrates suggesting their evolution in long isolation.

I determine the cellular and subcellular structure of protozoan isolates, explore their developmental cycles and examine their pathogenicity. I employ special techniques in light and electron microscopy, biochemical and immunological assays and protein and nucleic acid analyses. I evaluate morphological and molecular characters for the differential diagnosis of species and to provide reliable markers for biological traits of clinical and epidemiological significance. I determine relationships between the site of infection, parasite pathogenicity, host specificity and mode of transmission. Many protozoan species have fast life-cycles which out-race host immune responses. They invade host tissues, proliferate rapidly and then exit the host as encysted stages infective to other hosts. Resultant diseases are therefore often rapid, acute and severe. Other protozoan species have slow life-cycles where they hide in host tissues to optimize their chances of being taken up by predators or invertebrate vectors. These species cause protracted, chronic diseases often characterized by space-occupying lesions. Effective treatment and control relies on a thorough knowledge of the parasites involved, their effects on their hosts and the epidemiology of infections.

Research Interests

  • Enteric protozoa in humans:
    Various anaerobic protozoa cause gastro-intestinal or urogenital diseases in humans, including Trichomonas and Entamoeba. Parasite isolates vary markedly in their pathogenicity and drug susceptibility/resistance. Molecular biological studies are being conducted with colleagues at the Queensland Institute of Medical Research to find genetic markers for traits of biological and clinical significance.
  • Endosymbiotes in herbivores:
    Many herbivorous animals rely on endosymbiotic protozoa to help digest their food but little is known about the species inhabiting native Australian herbivores. Studies are being conducted to determine the microbial fauna of introduced eutherian mammals (ruminants and horses), native marsupials (kangaroos and wallabies), herbivorous reef-fish and wood-eating insects. Many novel ciliates and flagellates have been detected which are unique to their Australian hosts.
  • Haemoprotozoa in birds:
    A national survey is being conducted to determine the taxa of enteric and blood protozoa occurring in Australian birds. Specific projects are currently being conducted with Currumbin Sanctuary, The University of Queensland Veterinary School, Taronga Zoo, Queensland Museum and the International Reference Centre for Avian Haematozoa. Morphological taxonomic characters have proven unreliable in many instances therefore molecular studies are being conducted to characterize species.
  • Parasitic diseases of reptiles:
    Several projects are being conducted to identify protozoan parasites in blood and faecal samples from snakes and lizards in northern Australia, New Guinea and various Pacific Islands. These studies are focussed on parasites which may cause clinical diseases to indicate their involvement in declining host populations and to assess their potential for biological control of pest species.
  • Protozoa of fish and shellfish:
    The Department participates in the CRC for Aquaculture and has a strong history of research on marine parasites, mainly helminths and crustaceans. These studies are now being augmented by parallel studies on protozoan parasites of fish and shellfish. Projects are being conducted on endoparasites and ectocommensal fouling organisms of marine and freshwater fish and shellfish using facilities at the Stradbroke Island and Heron Island Research Stations.
  • Water contamination:
    Cryptosporidium oocysts and Giardia cysts are being detected with increased frequency in both raw and treated freshwater sources. However, little is known about their origin, viability, infectivity, virulence and pathogenicity. Parasites are being recovered from different hosts and genetically typed to indicate their host range and distribution. Different water treatment options are also being examined for their efficacy in removing or killing parasitic cysts.
  • Diagnostic keys:
    Modern information technology is being applied to the identification of protozoan parasites and their diseases. Differential diagnosis is frequently complicated by parasite pleomorphy, broad host specificity and geographic range and the relative nonspecificity of associated clinical disease. I want to amalgamate these discordant character sets into one comprehensive database using LucID software from CPITT (Centre for Pest Information Technology and Transfer) to develop interactive, random-access, multimedia keys to protozoan parasites in Australian hosts.


  • Doctor of Science, The University of Queensland
  • Graduate Certificate in Education, The University of Queensland
  • Doctor of Philosophy, The University of Adelaide
  • Bachelor of Science (Honours), The University of Adelaide
  • Bachelor of Science, The University of Adelaide


View all Publications



Book Chapter

  • O'Donoghue, P. J. (2005). Protistan parasites and myxozoa. In K. Rohde (Ed.), Marine Parasitology 1st ed. (pp. 12-17) Melbourne: CSIRO Publishing.

  • O'Donoghue, P. J. (2002). Provision of safe drinking water. In Mark Sandeman and Lesley Warner (Ed.), An investment in human and animal health: parasitology in Australia (pp. 13-13) Canberra: FASTS.

  • O'Donoghue, P. and Vanderduys, E. (1998). Survey for protozoan parasites in native animals from Musselbrook Reserve, Lawn Hill National Park. In Lyn Comben, Suzanne Long and Kathryn Berg (Ed.), Musselbrook Reserve scientific study report (pp. 191-199) Brisbane, Australia: The Royal Geographical Society of Queensland.

Journal Article

Conference Publication

Other Outputs

Grants (Administered at UQ)

PhD and MPhil Supervision

Completed Supervision

  • (2015) Doctor Philosophy — Principal Advisor

  • (2010) Doctor Philosophy — Principal Advisor

  • (2008) Doctor Philosophy — Principal Advisor

  • (2007) Doctor Philosophy — Principal Advisor

  • (2004) Doctor Philosophy — Principal Advisor

  • (2004) Doctor Philosophy — Principal Advisor

  • (2003) Master Philosophy — Principal Advisor

  • (2002) Doctor Philosophy — Principal Advisor

  • () Doctor Philosophy — Associate Advisor

  • (2007) Doctor Philosophy — Associate Advisor