Gyawali, P.

Khanal, S.

Shrestha, B.

University of Queensland eSpace

17 
International Journal of Veterinary Science 
 
www.ijvets.com P-ISSN: 2304-3075 E-ISSN: 2305-4360 editor@ijvets.com 
 
RESEARCH ARTICLE 
 
Intestinal Helminth Fauna in Sleepy Lizard (Tiliqua rugosa) in Australia 
 
Gyawali, P.1*, Khanal, S. 2 and Shrestha, B. 3 
 
1University of Queensland, School of Population Health, Herston Road, Herston, QLD, 4006, Australia; 2Institute of 
Agriculture and Animal Science, Rampur, Chitwan Nepal; 3Griffith University, School of Public Health, Parkland Drive, 
South Port, QLD, 4217, Australia 
 
 
ARTICLE INFO 
 
  
ABSTRACT 
 
 
Received: 
Revised: 
Accepted: 
 
January 16, 2013 
January 28, 2013 
January 31, 2013 
 
 
 
Key words:  
Australia 
Helminths 
Parasitic egg load 
Sleepy lizards 
 
 
*Corresponding Author 
Pradip Gyawali 
pradip.gyawali@uqconnect.edu.au 
 
 
 
Intestinal helminth parasites are the most common parasites that have negative 
impact on local population of overlapping home ranged lizards. The aim of the 
study was to identify the helminth fauna in lizards and determined the 
relationship between size of lizards and season with parasitic egg load. A total 
of 47 adult lizards, comprising 21 males and 26 females were captured in 
Bundey Bore, South Australia during September to December 2009 and faecal 
samples were collected. 
Higher proportions (89.4%) of subjects were infected by two kinds of helminth 
parasites (Thelandros trachysauri and Oochoristica trachysauri) with an 
average of 1.3 eggs gm-1 of faecal sample.  Male subjects had higher (100%) 
infection rate than females (80.8%). T. trachysauri was predominant   (89.4%) 
parasite in study population but O. trachysauri was found in only (19%) male 
and (11.5%) female populations.  
 
 
Cite This Article as: Gyawali, P, S Khanal and B Shrestha, 2013. Intestinal helminth fauna in sleepy lizard (Tiliqua 
rugosa) in Australia. Inter J Vet Sci, 2(1): 17-20. www.ijvets.com 
 
INTRODUCTION 
 
Parasitic helminths have ability to manipulate the 
fitness of their host in direct and indirect way. They can 
alter social behaviors (aggression, reproduction and 
parenting) of the host (Daszak et al., 2000; Klein, 2003; 
Thomas et al., 2005; Poulin, 2010). Parasitic infection 
also reduces the mobility of the host (Poulin, 2010; 
Fellous et al., 2011) that leads to the shortage of food, 
inability to find a mating partner, reduced fertility and 
survival rate as well as can be directed towards the death 
of the host (Zuk et al., 1998; Fenner and Bull, 2008). 
Intestinal parasitic helminthes are mainly transmitted 
through the ingestion of contaminated food and water 
(Thompson, 2001; Ashbolt, 2004). The transmission rate 
is higher in those animals; who has an overlapping home 
range (Loehle, 1995; Godfrey et al., 2009).  
Sleepy lizards (Tiliqua rugosa) live in group and have 
overlapping home range. This social behavior makes 
sleepy lizards; vulnerable to the parasitic infection (Bull, 
1987; Bull and Freake, 1999). In South Australia, there 
are large numbers of research was carried out with sleepy 
lizards and its conservation (Bull and Burzacott, 1993; 
Main and Bull, 2000; Bull, 2000).  All of those research 
focuses on the external parasites of sleepy lizards, 
genetics of ticks and behavior of the lizard. There was not 
enough importance given to the gastrointestinal parasites 
although they can cause temporary or permanent decline 
of local host population (Daszak et al., 2000). The 
available literature suggested that studies conducted in 
gastrointestinal parasites of sleepy lizard were early and 
mid 1900’s (Johnston and Mawson, 1947; Angel and 
Mawson, 1968). Those studies only looked types of 
helminthes parasites in sleepy lizards. 
The main aim of this study was to identify the 
helminth parasites in sleepy lizards and determine the 
relationship of infection with sex and size of lizards. This 
research also evaluates the effect of season in the parasitic 
egg load in the lizards. 
 
MATERIALS AND METHODS 
 
Study area and study population 
The study was carried out from September to 
December 2009 around Bundey Bore station of South 
Australia. The Bundey Bore station is situated (139˚21’ 
E, 33˚55’ S) in the mid north of South Australia. It is 
almost 150 kilometer from Adelaide (Leu et al., 2010). 
This study was conducted in different large seasonal 
sheep farms. Vegetation of the study area was small 
chenopod shrub land with few individual bushes (Kerr et 
al., 2003).  
Inter J Vet Sci, 2013, 2(1): 17-20. 
 
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Data collection 
A cross sectional survey was conducted between 
September and December, 2009. A total of 47 faecal 
samples were collected from 21 males and 26 females 
adult lizards by capturing and holding in hand. The fresh 
faecal samples were kept in the labeled (lizard 
identification number) sterilized sample collecting vial. 
Physical data such as weight, SVL, sex were taken. The 
collected samples were then transported to the biology 
laboratory of Flinders University of South Australia. 
Magnesium floating (Bowman  et al., 2003) method was 
applied to extract helminths ova from samples and a 
microscopic observation was carried out to identify the 
parasitic ova. All the findings from laboratory and field 
were stored into a Microsoft Excel spreadsheet. The 
numbers of eggs were log transformed prior to analysis. 
All the results were tested statistically significant (P<0.05) 
level. 
 
RESULTS  
 
Overall parasitic helminth infection was very high 
(89.4%) with an average of 1.3 eggs gm-1 of faecal 
sample. Helminth infection was higher (100%) in male 
lizards in comparison to the (80.8%) female lizards. The 
average egg load was similar, 1.3 eggs gm-1 of faeces in 
both sexes of lizards. The study population had two types 
of parasitic helminths (Thelandros trachysauri and 
Oochoristica trachysauri). Thelandros was the 
predominant (89.4%) parasite in both sexes of lizards but 
only 14.9% had Oochoristica.  All (100%) studied male 
had Thelandros and 19% Oochoristica. Similarly, female 
had 80.8% Thelandros and 11.5% Oochoristica in their 
faecal sample (Table 1). 
The average egg load was higher (1.7 eggs gm-1 
faeces) in September and decreased constantly in October, 
November and was lowest (0.9 eggs gm-1faeces) in 
December. Higher (1.9 eggs gm-1 faeces) in female was 
found in September but in male higher (1.6 eggs gm-1 
faeces) was found in October. In both sexes November 
and December had relatively lower (Table 1). Chi-square 
test showed that the total egg load in the different months 
in different sexes was statistically not significant (P>0.9).  
The overall egg load was higher (2.4 eggs gm-1 
faeces) in the lighter (<700gm).  The egg load was 
gradually decreased by increased weight of lizards and it 
was (2 eggs gm-1 faeces) in the heavier (>800) lizards. 
The result was statistically not significant (P>0.98) (Table 
2). The egg load of Thelandros was higher in all size of 
lizards than egg load of Oochoristica and the difference 
between the egg load of two parasites was statistically 
significant (P<0.05). 
 
The overall egg load was higher (2.6 eggs gm-1 
faeces) in the smaller (<30 SVL) lizards. The egg load 
was gradually decreased by increased size of lizards and it 
was (1.6 eggs gm-1 faeces) in the large (>31 SVL) lizards. 
The result was statistically not significant (P>0.93) (Table 
2). The egg load of Thelandros was higher in all shaped of 
lizards than egg load of Oochoristica and the difference 
between the egg load of two parasites was statistically 
significant (P<0.05). 
 
DISCUSSION 
 
Sleepy lizards survive in very difficult environmental 
condition. They live in empty wombat borrow (Leu et al., 
2010) with overlapping home range Bull, 1987; Bull and 
Freake, 1999). Sharing borrows could increases the risk of 
higher rate of parasite transition (Fenner and Bull, 2008; 
Godfrey et al., 2009). This might be the crucial factors for 
the higher (89.4%) infection rate. Parasitic infection may 
be result of the social behavior of the lizards. Male lizards 
are territorial in nature and travel more during mating 
season than female (Bull and Pamula, 1996).  Male lizards 
travel more than female during this time. This could easily 
escalate the chances of higher infection rate in male than 
female lizards. Ibrahim et al. (2005) looked at 
gastrointestinal helminthes in Chalcides ocellatus and 
found higher (87.6%) of lizards were infected by 
gastrointestinal parasites. He indicated that the parasitic 
infection levels in male were higher than female but there 
was not statistically significant difference between them.  
Sleepy lizards were active only in spring and early 
summer in South Australia (Bull, 2000). Lizards did not 
show any activities in winter and summer when the 
weather is too cold or too hot (Bull and Freake, 1999). 
Climate has impact on abundance of food intake by 
lizards. If they consume food frequently they might 
discard larger volume of faecal matter as well as parasite 
eggs. This might be the case of having higher egg load 
when the weather was suitable for lizards’ activities. 
Other researcher (Ibrahim et al., 2005; Al-Shareef A-al-D, 
1995) also indicated that climatic condition had changed 
the parasitic infection in lizards. 
Weight has been known as clear indicator of feeding 
and moving behavior in lizards (Van Damme et al., 1991). 
Heavier lizards required more food but unavailability of 
adequate food might suppress the egg load in heavier 
lizards. Similarly in smaller lizards might travel more and 
get more food. That leads to the faster gastrointestinal 
movement. The frequent gastrointestinal movement 
increases the chance of more eggs passing out in faeces.  
The study showed that egg load of Thelandros was 
higher in lizards. This might because Oochoristica need
Table 1: Monthly distribution of helminth egg load and disease prevalence 
    Thelandros +ve Oochoristica +ve 
 Total Observed (n) Male Female  Male Female  
Months Male (n) Female (n) (n) eggs/gm* (n) eggs/gm* (n) eggs/gm* (n) eggs/gm*
September 6 13 6(100%) 2.9 13(100%) 3.3 0 0 3(23.1%) 0.5 
October 3 2 3(100%) 2.8 2(100%) 2.2 1(33.3) 0.4 0 0 
November 7 9 7(100%) 1.2 4(44.4%) 1.9 2(28.6%) 1.6 0 0 
December 5 2 5(100%) 1 2(100%) 2.1 1(20%) 0.4 0 0 
Total 21 26 21(100%) 2.0 21(80.8%) 2.4 5(23.8%) 0.6 3(11.5%) 0.1 
 
Inter J Vet Sci, 2013, 2(1): 17-20. 
 
19
Table 2: Distribution of helminth egg load in different size and weight lizards 
   Thelandros +ve Oochoristica +ve 
Variables Total Obs (n) (n) eggs/gm* (n) eggs/gm* 
SVL <30 10 10(100%) 2.6 0 0 
 30-31 27 24(88.9) 2.2 5(18.5%) 0.2 
 >31 10 8(80%) 1.5 2(20%) 0.1 
Weight <700 13 11(84.6%) 2.2 2(15.4%) 0.2 
 700-800 25 24(96%) 2.2 1(4%) 0.03 
  >800 9 7(77.8%) 1.8 4(44.4%) 0.2 
 
Oochoristica need intermediate host to complete their life 
cycle and beetles are perfect intermediate host for 
Oochoristica (Criscione and Font, 2001). Without 
intermediate hosts Oochoristica cannot complete their life 
cycle. On the other hand, nematodes have direct life cycle 
they do not need intermediate host to complete their life 
cycle. Their eggs can survive on the soil and leaves of 
plants for long time under favorable condition (Anderson, 
1988). This might be responsible for higher egg load of 
Thelandros found in the sleepy lizards. Ibrahim et al., 
(2005) also reported higher nematode infection than 
cestode and had a weak positive correlation between 
nematode infection and SVL and body weight of 
Chalcides ocellatus. Similar result was reported in Egypt 
by Al-Shareef A-al-D (1995). 
 
Acknowledgement 
The authors would like to thank Flinders University, 
School of Biology Science to providing their laboratory 
for the study. We sincerely acknowledge Prof. Lesley 
Warner and her team at State Museum of South Australia 
for their support on species identification process. We also 
acknowledge Prof. Mike Bull for pursuing us to the work 
and thanks to his team for logistic support.  
 
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Intestinal helminth fauna in sleepy lizard (Tiliqua rugosa) in Australia

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Intestinal helminth fauna in sleepy lizard (Tiliqua rugosa) in Australia

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