Research Project: Life cycle of the blood parasite Hepatozoon theileri
Background:
Haemogregarines (blood parasites) are among the most commonly recorded apicomplexan protozoans to
parasitise frogs. In the past many frog haemogregarines were placed in the genus Haemogregarina. However, in
1996 these were all changed to Hepatozoon, based on the developmental stages of these parasites being more
characteristic with those of Hepatozoon than those of the genus Haemogregarina.
The genus Hepatozoon is, in contrast to Haemogregarina, characterised by merogony in the vascular endothelial
cells of the vertebrate host, typically without merogony in the peripheral blood erythrocytes, only intraerythrocytic
gamont stages being present.
Transmission of these protists occurs via the ingestion of a parasitised invertebrate host/vector including
mosquitos, mites, ticks, insects, and possibly, but doubtfully, leeches, in which, sporogony typically occurs in the
haemocoel.
Currently the only record of an anuran haemogregarine from South Africa is Hepatozoon theileri (Laveran, 1905),
described from the host Amietia quecketti (Boulenger, 1895) from the family Pyxicephalidae. Due to this, there
have been no study’s/research on the life cycle of blood parasites in South Africa.
Honours Section: Seasonal variance, prevalence, and parasitemia of Hepatozoon theileri
infecting the river frog Amietia quecketti.
Aim: To determine the seasonal changes undertaken by H. theileri, in terms of infection prevalence and
parasitemia on the host frog population.
Objectives:
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Sampling as many frogs as possible on a monthly basis.
Drawing blood for blood smears and parasite screening.
Determine parasite prevalence and parasitemia.
Conduct statistical analysis on collected data.
Predict optimal conditions and habitat of parasites.
Possible Masters Section: The life cycle and experimental transmission of Hepatozoon theileri.
Aim: To determine the full life cycle and morphology of Hepatozoon theileri, by means of experimental
transmission with regards to its vector and final host.
Objectives:
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To determine the possible vector in natural environment.
Complete experimental transmission of parasite to the vector and host.
Characterise the parasites different life stages, through basic morphology, ultrastructure (TEM &
SEM), and molecular techniques.
Determine the seasonal effect of the parasite on the host species.
Unique skills to be mastered from this project: Histology, Light Microscopy, Electron Microscopy
(TEM and SEM), Molecular techniques (PCR)
Possible Publication (International journal): The life history, ultrastructure and experimental
transmission of Hepatozoon theileri (Lavaran, 1905) (Apicomplexa: Adeleorina: Hepatozoidae), infecting the
vertebrate host Amietia quecketti (Anura: Pyxicephalidae) and the invertebrate host (???).
Contact detail
Prof. Louis du Preez. Email: [email protected] Building: E6 - G16 Website: www.nwu.ac.za/aacrg
Mr. Ed Netherlands. Email: [email protected] Building: E6 - G36 Website: www.nwu.ac.za/aacrg