Describing new species of Cryptosporidium in Fish
Water is increasingly recognised as an important vehicle for transmission of Cryptosporidium. The oocyst is
environmentally stable and resistant to inactivation by chlorine at doses commonly used in drinking water treatment.
Cryptosporidium can survive for long periods in both freshwater and saltwater and viable human-infectious oocysts
have been recovered from several bivalve species. Little is known about the prevalence, geographical distribution of
species of Cryptosporidium infecting fish and what the potential health implications are. Research in our laboratory has
identified human-infectious genotypes as well as several novel species. This project will focus on (a) screening new
isolates using PCR, sequencing as well as (b) the use of microscopy, PCR, sequencing and phylogenetic analysis to
characterise these novel genotypes as valid species. This is an exciting project as new species are continually being
identified which has generated publications for previous summer scholarship students.
For more information contact:
Prof. Una Ryan
Ph 9360 2482
Una.Ryan@Murdoch.edu.au
A/Prof. Alan Lymbery
Ph 9360 2729
a.lymbery@murdoch.edu.au
Prevalence and genetic characterization of Cryptosporidium and Giardia in marsupials
Cryptosporidium and Giardia are enteric parasites that infect a wide range of hosts and are transmitted by the faecaloral route and by contamination of water supplies. Their environmental stages (oo/cysts) can be shed in very large
numbers, are extremely hardy and easily spread by water. Symptoms vary from mild to severe diarrhoea and even death
(Fayer et al. 2004). There is no effective therapy for Cryptosporidium infection (Carey et al. 2004) and both parasites
are considered potential bioterrorist agents in the US (http://www.niaid.nih.gov/biodefense/bandc_priority.htm). Little
is known about the occurrence and impact of Cryptosporidium and Giardia in native marsupials, however a recent study
revealed the prevalence of Cryptosporidium in 3,557 fecal samples from wild eastern grey kangaroos in NSW was
between 0.32% to 28.5% over a 2-year period. A study of Giardia in Tasmanian native marsupials over a 3-yr period
revealed a prevalence of 21% in the 295 animals tested. Research in WA suggests that the prevalence of infection with
Giardia in a range of marsupials was 12.4%. Both host adapted and zoonotic species of Cryptosporidium and Giardia
have been detected in marsupials, highlighting the potential public health risk via transmission to humans.
The objective of this study is to screen marsupial fecal samples using molecular tools from areas of high and low human
interaction in order to determine (a) the prevalence of Cryptosporidium/Giardia in marsupials by PCR and (b) to
determine whether human-infectious genotypes of Cryptosporidium/Giardia are found in marsupials using PCR and
sequencing techniques. This study will therefore provide important information on not only the biology of
Cryptosporidium/Giardia infecting marsupials as well as the transmission dynamics of Giardia and will also identify if
there are any public health implications.
Prevalence and genetic characterization of blood-parasites in marsupials
Theileria, Babesia and Trypanosoma are haemoprotozoa (blood parasites) transmitted by insect vectors. There has been
no systematic study of native Australian haemoprotozoa and little is known of their epidemiology and impact.
The objective of this study is to screen marsupial blood samples using molecular tools from areas of high and low
human interaction in order to determine (a) the prevalence of haemoprotozoa in marsupials by PCR and (b) to
determine whether human-infectious species of haemoprotozoa are found in marsupials using PCR and sequencing
techniques. This study will therefore provide important information on not only the biology of haemoprotozoa infecting
marsupials as well as the transmission dynamics of haemoprotozoa and will also identify if there are any public health
implications.
Data generated from both these studies will be used to conduct climate change modelling to predict the future impacts
of climate change on the emergence of zoonotic disease caused by protozoan parasites on their marsupial hosts.
For more information contact:
Prof. Una Ryan
Ph 9360 2482
Una.Ryan@Murdoch.edu.au