past students and their projects
Sarani Sepalage
GASTROINTESTINAL PARASITES OF WILD MAMMALS IN FOUR MAJOR NATIONAL PARKS IN SRI LANKA
Sarani carried out her undergraduate project on gastrointestinal (GI) parasites of wild mammals in four major National Parks: Wilpattu, Udawalawe, Wasgamuwa and Horton Plains. She collected fresh faecal samples from ten mammal species and analyzed using a sedimentation technique, iodine and saline smears, Sheather’s sucrose floatation. Of the 70 faecal samples analysed, she found 94% were infected with GI parasites. Nineteen parasite species were recorded, of which Entamoeba, Isospora, Balantidium, Fasciola, Moneizia, Dipylidium, strongyles, Toxocara, Trichiurus and hookworms were common infections. Her study provides baseline information of the enteric parasites of mammals and their distribution in the four parks. She published her work in the Journal of Threatened Taxa. Sara is currently working as a teaching assistant at the Open University of Sri Lanka.
Yasara Rathnayake
EFFECT OF TWO INSECTICIDES, PROFENOPHOS AND ABAMECTIN ON THE TADPOLES OF ASIAN COMMON TOAD
Yasara tested the lone and cocktail effect of two agrochemicals: profenophos and abamectin on tadpoles of the Asian common toad, Duttaphrynus melanostictus. She exposed five-days post-hatch tadpoles to a series of of ecologically relevant concentrations of the two chemicals and a mixture of the two. Both pesticides caused lethal and sublethal effects even at low field level concentrations. Abamectin was more toxic than profenofos. Exposure reduced the survival of tadpoles, growth parameters (snout-vent length and body mass), took a longer time to metamorphose, developed malformations and showed behavioural abnormalities like altered feeding and swimming behaviours. Profenophos induced scoliosis and kyphosis, abamectin caused edema while the cocktail exposed tadpoles developed both scoliosis and edema. The effects of the cocktail exposure were more severe than the lone effects of the two. This was Yasara's undergradaute project which she later published in the Ceylon Journal of Science.
Prasanga Diyes
SPINOSE EAR TICK OTOBIUS MEGNINI IN RACE HORSES
Prasanga carried out an extensive study to determine the life history characteristics, population dynamics, biological control agents, insecticide resistance and the vector potential of spinose ear tick Otobius megnini causing otoacariasis (intra-aural tick infestation) in stabled horses in Nuwara Eliya race courses. Prasanga found that the tick infestations were heavy during warmer months and recorded Babesia sp. in ticks removed from the ear canal of horses. He also reported a parasitoid scuttle fly, Megaselia scalaris and five predatory ant species: Tapinoma melanocephalum, two species of Monomorium, one species of Pheidole and Crematogaster as potential biological control agents of this tick. Prasanga tested the susceptibility of this tick for four insecticides: permethrin, DDT, malathion and flumethrin using a WHO recommended Larval Packet Test. Of the four chemicals, flumethrin was found to be the best acaricide in controlling the tick. PHe produced over four papers and a book chapter from his work and graduated with his M.Phil. Prasanga also carried out an island-wide survey on the diversity and distribution of tick species infesting goats as his undergraduate project. Currently Prasanga is doing his Ph.D. on ticks and tick borne infections at the University of Saskatuwan, Canada.
Shanika Dissanayake
GASTROINTESTINAL PARASITES OF CAPTIVE AND FERAL HORSES
Shanika examined the gastrointestinal parasites of feral and captive horses in Sri Lanka using direct saline and iodine mounts, simple test tube flotation, Sheather’s modified sucrose flotation and sedimentation technique followed by McMaster counting. She sampled 73 horses, of which all the feral horses in the Delft Island were infected. She recorded six species of parasites: Anoplocephala sp., Parascaris equorum, Strongylus sp. Isospora sp. Entamoeba sp. and Giardia sp. Strongyle infections were recorded in all the feral horses with high intensity. It is highly pathogenic and the most damaging parasite of horses worldwide. Further investigations on strongyle infection is highlighted to responsible for the high mortality recorded in the feral horses in the Delft Island which is now declared as a National Park to conserve the feral horses. Shanika is now attached to the Ministry of Public Administration, Home Affairs, Provincial Coun & Loc Gov.
Lalith Ekanayake
BIOLOGY AND CONSERVATION OF GREEN TURTLES NESTING AT THE KOSGODA ROOKERY IN SRI LANKA
Lalith studied green turtles nesting in Kosgoda rookery in the south-western coast for over a five years to determine the nesting season, biometricts of nesting females, eggs and hatchling, nesting behaviour, genetic diversity and nest paternity in natural nests. He found that nesting takes place year round, with a peak in March to June. Females lay an average of 289 eggs in a season and re-visit the beach after 1-3 years showing a high nest site fidelity. He also reported the reproductive output of the females hatching success, incubation duration. Molecular data showed high allelic diversity in microsatellite loci tested. As promiscuous breeders, the offspring of 47% females was multiply sired by two or three males. Lalith completed his Ph.D. and is now working as a conservationist in his Bio-conservation NGO and a Marine Turtle Specialist at the IUCN/SSC-MTSG. We continue to collaborate our work on turtle conservation.
Uthpala Jayawardena
EFFECT OF PESTICIDE, CERCARIAE AND UV-B RADIATION ON TWO COMMON ANURANS
Uthpala tested the effect of four commonly used pesticides, trematode infection and UV-B radiation exposures on the common hourglass tree frog and the Asian common toad under laboratory conditions. All three exposures caused significant reduction in survival and growth retardation and this effect was enhanced when tested synergistically. Uthpala produced eight full papers and several abstract communications at local and international fora. She won a President's award and F.P.Amerasinghe Memorial Postgradaute award for her research. Uthpala also studied the cercariae diversity as her undergradaute project in my lab and is now working as a senior lecturer at the Department of Zoology, University of Sri Jayawardenapura. We continue and collaborate our work on ecotoxicology of amphibians.
Gajavathany Kandasamy
GASTROINTESTINAL AND BLOOD PARASITES OF SHEEP IN JAFFNA
For her undergraduate project, Gajavathany studied the prevalence, intensity gastrointestinal (GI) and blood parasites of sheep at Kaithady farm in the Jaffna District. Fresh faecal samples during dry and rainy seasons. salt floatation, direct saline and iodine smears and sedimentation method. Geimsa stained smears were prepared from the blood samples. Identification of the parasites was based on light microscopic morphology and faecal culture was done to identify strongyles. Seven genera of GI parasites including Haemonchus contortus, Toxocara, Trichuris, Moniezia, Eimeria, Giardia, amphistome eggs and an unidentified strongyle type eggs were recorded. She published her work in the Journal of the National Science Foundation and joined the Department of Zoology at the University of Jaffna. She is now completing her Ph.D. at the University of Colombo.
RISK FACTORS AND SEASONALITY OF OTOACARISIS IN KANDY AND ANURADHAPURA DISTRICTS
Kalpani carried out a case control, patient follow-up study to determine the risk factors and seasonal pattern of otoacariasis in Kandy and Anuradhapura districts for her M.Phil. degree. In Kandy, infestations were year-round while in Anuradhapura, it was seasonal with a peak in December to February. The disease incidence did not have any relationship with climatic factors but more cases were recorded following heavy rains. Children were a risk group in both districts while females were a risk group only in Kandy district. Engagement in outdoor activities was a risk factor in both districts. In the Kandy, presence of wildlife in the neighbourhood and in Anuradhapura, presence of domesticated animals posed risks to household members. Life cycles of four selected tick species were studied under laboratory conditions. Rickettsia DNA was detected in a tick removed from the ear canal of an infant from Anuradhapura. Kalpani received a President's award for her research work on ticks.
Kalpani Bandaranayake
Nirupama Abeysekara
COMPARATIVE CROSS SECTIONAL SURVEY ON GASTROINTESTINAL PARASITES OF CAPTIVE, SEMI-CAPTIVE, AND WILD ELEPHANTS
Nirupama carried out an island-wide survey was on the gastrointestinal parasites of the Sri Lankan elephant (Elephas maximus maximus) collecting fresh fecal samples from wild, captive, and semi-captive elephants. she analysed them using modified salt floatation, Sheather’s sucrose floatation, direct iodine smears, and sedimentation methods. Of the 85 elephants examined, 68% were positive for parasites. A higher prevalence of infection was observed in the wild elephants (93%) compared to semi-captive elephants (55%) and captive elephants (25%). Ten types of GI parasites were observed, nine of which were recorded in wild elephants. Among them the most common infection was strongyles with high worm burden. A salient feature of the study was one captive elephant at the Temple of the Tooth being infected with the tapeworm Anoplocephala sp. Nirupama is now doing her Ph.D. at the University of Queensland, Australia.
Nuwandi Pathirana
MULTIPLE PARASITISM: AGE DEPENDENT RESISTANCE & TOLERANCE
For her M.Phil degree, Nuwandi studied host tolerance and resistance by exposing two larval trematodes: furcocercous and pleurolophocercous cercariae to hour-glass tree frog Polypedates cruciger under laboratory conditions. Exposure affected the growth and survival of tadpoles and exposed tadpoles developed malformations (kyphosis, scoliosis). Older tadpoles showed higher tolerance and resistance to parasitism. In a combined exposure to the two cercariae, once the pleurolophocercous entered, later infection with furcocercous had an additive effect on the host making the combined infection more severe. However, when the furcocercous entered first, later infection with pleurolophocercous had an antagonistic effect on the host lowering the severity to infection. Variation in sequence of exposure of parasites lead to additive, antagonistic, or synergistic effects, reinforcing the notion of the existence of cryptic interactions between parasite and host communities. Nuwandi is now reading for her Ph.D. at the Murdoch University in Australia.
Praveena Jeganathan
KPA OF FARMERS TOWARDS PESTICIDE USAGE & PESTICIDE INDUCED DEMASCULINATION OF FROGS EXPOSED TO PESTICIDES
Praveena carried out a survey to assess the knowledge, practices and attitudes (KPA) towards pesticide usage among the fruit and vegetable farmers in the dry and wet zones. She found that the main factors contributing to farmers’ KPA were farmer training and Agricultural Instructors visit. She also studied the acute and chronic toxicity of three commonly used insecticides: profenofos, diazinon and carbosulfan on the common hourglass tree frog, Polypedates cruciger under laboratory conditions. Chronic exposure to ecologically relevant doses showed a decrease in the survival, growth differences and lengthening of the larval period. None of the tadpoles or metamorphs developed any external malformations. Froglets were euthenised and histological preparations og testis showed that the exposed male frogs had developed testicular oocytes.
Sodini Ariyaratne
DIVERSITY AND DISTRIBUTION OF TICK SPECIES ASSOCIATED WITH HUMAN OTOACARIASIS AND RISK FACTORS OF TICK INFESTATIONS
Sodini collected ticks in the intra-aural ear canal of patients (otoacariasis) visiting the ear, nose, throat (ENT) clinic in five districts (Anuradhapura, Kandy, Kurunegala, Nuwara Eliya and Ratnapura). The highest number of human otoacariasis cases was reported from Kandy followed by Ratnapura and the lowest number was recorded from Nuwara Eliya Five tick species were identified, of which nymphs of Dermacentor auratus constituted 91% of the collection. Other species included Rhipicephalus sanguineus, Hyalomma isaaci, Haemaphysalis bispinosa and Otobius megnini. The majority of patients (were children under 10 years. A questionnaire survey collected socio-ecological risk factors of otoacariasis. Involvement in outdoor activities, presence of wild animals around the house, close proximity of the house to a forest and occupation were major risk factors. Sodini completed her M.Phil and has now started her Ph.D. on rickettsia infections carried by ticks in my lab.
Piyumali Perera
Helminth eggs
GASTROINTESTINAL PARASITES OF DOGS IN HANTANA WITH ZOONOTIC POTENTIAL
Piyumali examined the faecal samples of domestic, semi domestic and stray dogs in Hantana area to determine the prevalence, intensity and types of gastrointestinal parasites. Samples were processed by modified salt floatation, Sheather’s sucrose floatation and direct iodine mounts followed by morphological identification. Of the 90 dogs examined, 90% were infected. Mixed infections were more common. Thirteen parasites found, 11 of which were zoonotic. Ancylostoma sp. was the most prevalent infection followed by Toxocara canis and Spirocerca lupi. Other zoonotic species recorded were Entamoeba, Toxascaris, Trichuris vulpis, Blastocystis, Strongyloides, Isospora, Capillaria aerophyla and Giardia. This is the first record of Toxascaris sp. from dogs in Sri Lanka. Piyumali publish this undergraduate research in the Journal of the National Science Foundation. She is now a junior colleague of mine and we continue to work on gastrointestinal parasites.
Nayana Wijethilake
CURRENT STATUS OF TORTOISESHELL TRADE IN SRI LANKA
Nayana was in my lab for a short period as a research assistant and he carried out a survey to assess the status of tortoiseshell trade in major tourist cities in Sri Lanka. He collected infomation by interviewing sales associates or store owners after informed consent. Of the 65 shops visited in 11 locations, none of the retailers claimed that they currently sell any tortoiseshell products but about one-third reported that they had been involved in the shell trade until the late 1990s. Few shops, older than 10 years still carried some previously stocked, unsold items but they no longer buy new shell products from suppliers. All respondents were well aware that selling of tortoiseshell products was illegal and sea turtles were protected. Survey results showed tha the tortoiseshell trade in Sri Lanka may no longer be considered a significant threat to hawksbill recovery but continued vigilance is needed to monitor clandestine trade if any. Nayana is a senior lecturer in Zoology at the University of Sri Jayawardenapura and we continue to work on conservation.
Kethmini Aviruppola
GASTROINTESTINAL PARASITES OF CAPTIVE MAMMALS AT THE DEHIWALA ZOOLOGICAL GARDENS
Kethmini carried out a cross sectional, coprological study on gatrointestinal (GI) parasites of captive mammals in the Dehiwala National Zoological Gardens. She collected fresh faecal samples from all the mammal species belonging to nine orders (Primates, Carnivora, Perisodactyla, Artiodactyla, Proboscidea, Erinaceomorpha, Lagomorpha, Rodentia and Diprotodontia). She found 63% of the individuals were positive for GI parasites and recorded 13 types of GI parasites: Trichuris sp., strongyle type, Strongyloides sp., Toxocara sp., hookworm, Spirometra sp., Moniezia sp., Nematodirus sp., Giardia sp., Blastocystis sp., Balantidium sp., Entamoeba sp., coccidians and unknown protozoan cysts. Some are highly pathogenic while others are incidental. Results highlight the importance of faecal analysis before regular deworming and a more targeted approach to manage the pathogenic species when designing appropriate parasite control strategies.
Nuwandi Pathirana
CERCARIAL MORPHOTYPES AND FROG MALFORMATIONS
For her undergraduate project, Nuwandi examined whether all cercariae types induce malformation in the hourglass treefrog Polypedates cruciger by exposing ten days post-hatch tadpoles to nine types of cercariae shed by the freshwater snail, Melanoides sp. Survival, growth and development of malformations were recorded in 15 and 30 days post-hatch tadpoles and metamorphs. Of the nine cercariae types, only three: gymnocephalous (Type C) and two pleurolophocercous types (H and I) induced effects on the host in the preliminary study. Both cercariae types induced axial malformations such as kyphosis and scoliosis. The exposures did not have any change in the size of the tadpoles, but the tadpoles exposed to types H and I had a prolonged growth period (ANOVA - General Linear Model, p < 0.001). Cercariae type C caused open wounds in the belly area of the host. This type of malformations has not been recorded in frogs before. The results show that only some cercariae types induce effects on the frog host, possibly the cercariae types that use the tadpoles as the intermediate host to enter the definitive host and to complete its life cycle.
Sumagali Kaliyanathan
ECTO AND ENDO PARASITES OF PERI-DOMESTIC RODENTS IN THE UNIVERSITY PREMISES WITH POTENTIAL ZOONOSES
Sumangali caught 21 rodents: the common house rat (Rattus rattus), the Indian house mouse (Mus musculus), and bandicoot (Bandicota sp.) live using single-catch rat traps and screened for ecto and endoparasites. She found 11 parasites: Oriental rat flea, Xenopsilla cheopis (ecto-parasite) in R. rattus and endo-parasites: Cysticercus fasciolaris (strobilocercus larva of Taenia taeniaeformis) strongyles, Hymenolepis diminuta, Moniliformis moniliformis, Raillietina sp Unidentified strobilocercus larva of Taenia sp Trichuris sp., strongyloides, unidentified coiled larvae and spherical eggs with live larvae. Tapeworms were the predominant, C. fasciolaris being the most common. Mixed infections were common. A bandicoot was infected with Raillietina sp. which provides the first report of occurrence of Raillietina in bandicoots. Of the 11 species, five were zoonotic: H. diminuta, M. moniliformis, C. fasciolaris, Raillietina sp. and X. cheopis.
Rukmali Athurupana
SCHISTOSOMIASIS IN CAPTIVE ELEPHANTS
Rukmali examined the prevalence of schistosomiasis in captive elephants at Pinnawala Elephant Orphanage, Millennium Elephant Foundation and other captive elephants of private owners. Dung samples were analysed using filtration method. Residue of the 50 μm filter were exposed to light to enhance the emergence of miracidia from eggs. The live movements of miracidia were observed and miracidial counts were taken. Miracidia from positive samples were used for artificial infection of aquatic snail species, Lymnaea and Indoplanorbis which were suspected as intermediate host. Several species of snails were collected from water sources near the study sites and both artificially infected and field caught snails were exposed to sunlight to release cercariae A total of 13% of the elephants were infected. This was much lower compared to the 80% infection recorded six year ago (2000). None of the pregnant females were infected even though they were not dewormed. The low prevalence of schistosomiasis may be due to better management practices and proper deworming strategies.
Ridma Neelawathura
EIMERIA SPECIES CAUSING COCCIDIOSIS IN GOATS IN KANDY AND NUWARAELIYA
Ridma collected fresh faecal samples from goats and separated Eimeria oocysts using a modified salt floatation and sedimentation techniques. She reported an overall prevalence of coccidia infection 46%, with Kandy district recording a higher prevalence (59%) than Nuwara Eliya district (37%). She morphological identified eight species of Eimeria belonging to Family Eimeriidae (E. arloingi, E. ninakohlyakimovae, E. jolchijevi, E. caprina, E. christenseni, E. hirci, E. aspheronica and E. alijevi). Five of them were reported from Nuwara Eliya district while all eight were found in Kandy district. Mixed infections with two or more Eimeria species were common. Of the eight species recorded in this study, E. caprina presents a new record for goats Sri Lanka. This species was found only in Kandy district from goats in a farm at Uda Peradeniya. Kids were more affected than the adults. Comparatively, infection was less prevalent than the goats in the dry zone of Sri Lanka where the prevalence is over 80%.
Samartha Harischandra
EFFECT OF MOSQUITO LARVICIDE ABATE® ON THE ASIAN COMMON TOAD
Samartha studied the effect of mosquito larvicide, Abate® which has temephos as the active ingredient, on the Asian common toad, Bufo melanostictus, under laboratory conditions. The LC50 values of Abate after a two week exposure to one-day old tadpoles (Gosner stage 21 -24) and one-week old tadpoles (Gosner stage 25) were 16.56 ppm and 17.03 ppm, respectively. Chronic exposures to Abate at effective field concentrations used in mosquito control programmes (WHO recommended doses) had a significant effect on the survival when exposed to egg stage (Gosner stages 12-14), and one day old tadpoles but not to one week old tadpoles. Exposed tadpoles also developed malformations such as rotation of bones, micromelia of the limb bones, hemimelia of femur, skin webbing in the hind limbs and ectrodactyly. Edemas were also observed in the exposed tadpoles. She found that Abate is highly lethal to early stages of the tadpoles but the toxicity subsided as the tadpoles grew older.
Poornima Mahagedara
PARASITES OF TWO HOUSE GECKO SPECIES
Poornima studied ecto and endo parasites of two house gecko species, the Asian house gecko, Hemidactylus frenatus and the four-clawed gecko, Gehyra mutilate inhabiting urban houses in Kandy and Kegalle. She collected geckos and dissected after anesthetizing. Of the 21 individuals, 47% were infected with ecto and endo parasites. Both were infected with nematodes and flukes. In addition mites (Geckobia sp.), (Acanthocephalus serendibensis) and ciliates were found only in H. frenatus. Although the two gecko species co-occur, some parasites show host specificity. Nematode Oxyuris sp. was the most common parasite. Acanthocephalus serendibensis in H. frenatus is a new host record. It occurred at high intensity of 5-10 worms per host. There were no parasites in the blood or body cavity of the geckos examined. More female were infected with parasites than males. Hemidactylus frenatus harboured parasites of all five groups while G. mutilate had only two groups.
Samanmali Gunathilake
ACANTHOCEPHALANS IN TWO COCKROACH SPECIES IN PERADENIYA UNIVERSITY PREMISES
Samanmali collected two cockroach species, the American cockroach, Periplaneta americana and the Surinam cockroach Pycnoscelus surinamensis in the University Premises, Peradeniya . Of the 86 examined, 35% of P. americana was infected with the acanthocephalan, Moniliformis moniliformis. Four developmental stages; acanthor, precanthellae, encysted cystscanth and excysted cystacanth were found in the cockroach. Both adult cockroaches and nymphs were infected. More female cockroaches (92%) were infected than males (58%). The prevalence of infection was significantly higher in the cockroaches caught in the university chicken farm (59%) where the definitive host rats were abundant than those inhabiting a hall of residence in the University (20%). None of the P. surinamensis (29) were infected. Acanthocephalans have a worldwide distribution and cause zoonotic disease in humans called acanthocephaliasis
Vishvapali Kobbekaduwa
BAlATIDIUM INFECTIONS IN MARCH CRCODILE IN JAFFNA PENNINSULAR
Vishvapali analysed faecal samples from the mugger or the marsh crocodile, Crocodylus palustris in the Jaffna Penninsular. She used the modified salt floatation followed by morphological identification and light microscopy. A total of 21 faecal samples were analysed from two locations in Jaffna: Ampan and Sarasalai. All the samples were positive for cysts of Balantidium sp. The intensity of infection varied among the individuals with extremely high cyst counts in some individuals. This study provides first record of Balantidium infections in Crocodylus palustris of Sri Lanka. The mugger is found in many locations in the country with a majority from Yala and Wilpattu National Parks in large rivers, marshes, reservoirs and tanks in the low country dry zone in addition to Jaffna Peninsula.
Kalpani Bandaranayake
Community dogs are common in low income tea estates
ZOONOTIC GASTROINTESTINAL PARASITES OF DOGS IN A TEA ESTATE COMMUNITY: A ONE HEALTH APPROACH
Kalpani studied gastrointestinal parasites in humans, dogs and in soil in a low income tea estate community in the Central Province. Parasites were isolated and identified morphologically, morphometrically followed by molecular confirmation. Of the 50 dogs examined, 86.% was infected harboring 13 GI parasites, of which nine were zoonotic: Toxocara canis, Strongyloides sp., Entamoeba coli, hookworm, Trichuris sp., Giardia duodenalis, Spirocerca lupi, Toxascaris sp., and Taenia sp. In addition, Entamoeba histolytica, coccidia, unidentified trematodes and cestodes were also found in dogs. Six types were identified in humans, of these four types, E. coli, G. duodenalis, Strongyloides sp. and Blastocystis sp were potentially acquired from animals. Soil carried infective L3 and eggs of nematodes, cysts of E. coli and eggs of T. canis all of which were zoonotic.
Prasanga Diyes
DIVERSITY AND DISTRIBUTION OF TICK SPECIES INFESTING GOATS WITH TWO NEW HOST RECORDS FROM SRI LANKA
Prasanga carried out an island-wide study on ticks that infest the domestic goat, Capra aegagrus hircus and collected 2,628 ticks from 22 districts in 740 goats belonging to various breeds. Eight species of ticks belonging to two genera Haemaphysalis and Rhipicephalus (Family Ixodidae): Haemaphysalis bispinosa, H. intermedia, H. cuspidata, Rhipicephalus sanguineus, R. haemaphysaloides, R. turanicus, R. (Boophilus) annulatus and R. (Boophilus) microplus were recorded. The most common species in the overall collection were H. intermedia (44.0%) and H. bispinosa (43.8%). Haemaphysalis bispinosa was the dominant species in wet and intermediate zones, except in few locations. In these exceptions H. intermedia was the dominant species, which was also the most abundant species found in the dry zone. Haemaphysalis bispinosa and R. sanguineus were restricted only to wet and intermediate zones. Of the eight tick species found, two species R. turanicus and R. microplus were new host records for Sri Lanka. All three stages of the dominant tick species were found on goats except for immature stages of R. haemaphysaloides and R. sanguineus. Most ticks preferred anterior side of the body with one exception, R. microplus which was more attracted to posterior side of the host. Some of these tick species are known vectors of many tick borne diseases of human and livestock.
Upekha Dissanayake
HAMOPARASITES OF DIARY CATTLE
Upekha studied the prevalence and distribution of haemoparasites in the dairy cattle in the dry, intermediate and wet zones of Sri Lanka. She collected blood samples from cattle and background information of the farm management and clinical history of the cattle. Geimsa stained blood samples were examined under light microscopy. A total of 264 blood samples were collected from 12 districts. Overall, 8% of the cattle had hemoparasites. The most common parasite was Theileria spp with 6% overall prevalence. However, the cattle in the dry and intermediate zones had higher prevalences of 0% and 11%, respectively while it was only 2% in the wet zone. The overall prevalence of Babesia infection was less than one percent. None of the blood samples analysed was infected with trypanosomes although recorded in cattle previously.
Shamitha Abeyrathne
Laboratory exposure of tadpoles to profenofos
EFFECT OF PESTICIDE PROFENOFOS ON TADPOLES THE ASIAN COMMON TOAD
Shamitha determined the gonadal malformations upon exposure to endocrine disrupting compounds such as pesticide on demasculinization and feminization in amphibians. She exposed the Asian common toad, Duttaphrynus melanostictus to profenofos at environmentally relevant concentrations. After metamorphosis the froglets were reared until Gosner Stage 46. The metamorphs were euthanized and gonads were dissected out. Histological sections of gonads were prepared using Bouin’s fixative and stained using H & E. Exposed tadpoles showed higher mortality, were smaller in size, took longer time to metamorphosis and showed abnormal behaviors such as reduced feeding and abnormal swimming behaviours. There were no differences in the histological sections of the exposed metamorphs and those in the control. Shamitha is now working as an environmental officer at the Central Environmental Authority.
Naveen Dissanayake
KNOWLEDGE PRACTICES AND ATTITUDE OF COASTAL COMMUNITY ON SEA TURTLES
Naveen conducted a questionnaire survey to assess the knowledge, practices and attitude towards sea turtle conservation and the prevalence of consumptive use among the coastal community. One hundred villagers were interviewed. The majority of the coastal community was poor with only elementary or less education and mainly involved in fishing or fishing related occupations. Respondents from nesting areas had a significantly better knowledge about sea turtles and positive attitude towards sea turtle conservation than those from villages with no nesting, by-catch villages. Even though a large number of participants from nesting villages had eaten turtle meat and/or eggs, not many of them claimed that they had been involved in buying or selling turtle meat, eggs or other products and much of the consumption took place more than five years before the study period. However, there was a high prevalence of consumptive use among villagers in Kandakuliya, where there is high turtle by-catch.
PARTIAL CHARACTERISATION OF EXCRETORY-SECRETORY ANTIGENS AND MORPHOLOGY OF RUMEN PARAMPHISTOMES IN NEAT CATTLE
Ambikai attempted to isolate and characterise excretory-secretory (ES) antigens of rumen paramphistomes which could be used in taxonomic identification. Adult flukes were collected from rumen of infected cattle at the Municipal Abattoir, Kandy. ES antigens were prepared by in vitro culture. Analysis of ES antigens was done using SDS PAGE. The antigenic specificity of collected ES antigens were analysed by immunoblotting using known positive cattle serum. For morphological analysis processed specimens were identified using taxonomic keys. This distinguished five different genera of paramphistomes belonging to two families: Genera Calicophoron, Cotylophoron and Paramphistomum of family Paramphistomidae and genera Carmyerius and Fischoederius of family Gastrothylacidae. The immunoblotting data show considerable variation in the antibody binding pattern indicating specificity in antigenicity to host antibodies.
Achele Rajapakse
DIVERSITY AND DISTRIBUTION OF CATTLE TICK IN SRI LANKA
Achele carried out an island–wide survey of cattle ticks in all the districts in Sri Lanka. From each district, at least 20 cattle were sampled. Tick attachment site of the host body was noted down. A total of 2,457 ticks were collected from 548 cattle. Ten tick species belonging to six genera (Amblyomma, Boophilus, Haemaphysalis, Hyalomma, Rhiphicephalus and Nosomma) were identified. The most abundant species was Boophilus microplus (55%) followed by Rhipicephalus haemaphysaloides (15%). Other species included Haemaphysalis bispinosa, Hyalomma marginatum isaaci, Haemaphysalis intermedia, Amblyomma integrum, Rhipicephalus sanguineus, Boophilus annulatus, Hyalomma brevipunctata and Nosomma monstrosum. A finding of great significance was the N. monstrosum on cattle as a new host record for Sri Lanka. Majority of the collection (88%) was adult ticks (66% females and males 34%) and the rest was nymphs(12%). Nymphs were only recorded in B. microplus, H. bispinosa and A. integrum. Larval stages of any tick species were not encountered on the cattle host.
Vishvapali Kobbekaduwa
FIRST RECORD OF TAPEWORM MONIEZIA INFECTIONS IN LEOPARDS: ENTERIC PARASITES OF FOUR WILD CATS IN SRI LANKA
Vishvapali and Coroline analysed enteric parasites of the four wildcats: Leopard, Fishing Cat, Rusty-spotted Cat and Jungle Cat s in Sri Lanka. All four, except the Jungle Cat, are listed threatened. Parasite eggs and cysts were isolated and morphologically identified using iodine smears and a modified salt flotation. The intensity of infection was quantified using a McMaster counting technique. The presence of Moniezia sp. in Leopards in the Horton Plains National Park with an intensity of was unexpected. Moniezia is a common GI parasite of ruminants. Cross species infection with Moniezia could be possible due to accidental ingestion of larva infected oribatid mites, the intermediate host in the pasture while feeding on carcasses. Vishvapali is now studying tick-borne infections for her Ph.D. at the Michigan State University, USA.
Bhagya Janananda
AMPHISTOMES IN NEAT CATTLE SLAUGHTERED AT KANDY ABATTOIR
Bhagya studied the amphistomes (rumen flukes) in cattle brought from different part of the country for slaughtering at the Kandy abattoir. She collected the flukes , fixed in 70% alcohol, stained using Aceto Alum Carmine and slide mounted. Nine types of amphistomes representing two families: Gastrothylacidae (92%) and Paramphistomidae (64%) were identified. The genera Gastrothylax, Fischoederius and an unidentified genus (GNI-1) represented the Family Gastrothylacidae while Paramphistomum, Cotylophoron, Calicophoron, Explanatum and two unidentified genera (PNI-1, PNI-2) belonged to the Family Paramphistomidae. She observed heavy infection of amphistomes of the Family Gastrothylacidaein in large patches in the rumen while those of the Family Paramphistomidae were found in smaller numbers and were more uniformly distributed in the rumen. Mixed infections were common. The genus Cotylophoron was a first record.
Naveen Wijesena
PROTOZOAN GUT PARASITES IN THREE ANURAN SPECIES FROM A NATURAL POND IN THE GANNORUWA FOREST RESERVE
Naveen collected tadpoles of three anurans: Polypedates cruciger, Limnonectes kirtisinghei and Bufo melanostictus from a natural pond in the Gannoruwa Forest Reserve (Kandy District) and carried out a parasitic survey of their gut parasites once they metamorphosed into adults. Gut smears were fixed in Schaudinns’ and stained with Harris’ Haemotxylin and aqueous Eiosin. Four genera of protozoans were identified: Opalina, Protoopalina, Zelleriella and Nyctotherus. The distribution of parasites showed a marked difference among the three host species even though the they were reared in the same habitat. This difference could be due to the food, feeding habits, microhabitat preference and the duration of the tadpole stage of the host species. The study indicates that even though different tadpole species are found in the same habitat, the differences in levels and pattern of parasitic infections result from different physiological and behavioural adaptations. These factors may determine their resistance and/or tolerance to parasitism.
PREVALENCE OF GASTROINTESTINAL PARASITIC INFECTIONS IN NEAT CATTLE REARED UNDER DIFFERENT MANAGEMENT SYSTEMS
Kanchana investigated the prevalence of gastrointestinal (GI) parasites in four different cattle management systems: zero grazing small-scale farm at Peradeniya, limited grazing large-scale farm, a semi-zero grazing small-scale farm at Rajawatte, communally grazed traditional cattle from large nomadic herds brought into the abattoir from the dry zone. Faecal samples were collected and analysed. A high prevalence of parasitic infections was observed in the semi-grazing small-scale farm animals at Rajawatte study site and at the abattoir where cattle were allowed for free grazing, whereas a low prevalence of infections was observed in small-scale zero grazing farm at Peradeniya. Cattle in all four sites were positive for many nematode eggs, Ascaris sp. being predominant. A high prevalence of trematode infections observed in free grazing animals. However, the overall protozoan infections were not heavy. The egg counts had increased following a high rainfall
SANDFLY AS THE POTENTIAL VECTOR OF LEISHMANIASIS
Janaka collected sandfly (Phlebotomus argentipes) and carried out field observations on the vector behaviour and population dynamics in three selected sites in Kandy district where cases of leishmaniasis have been recorded. Sandflies caught in these three sites were anslysed in the lab for the presence of parasite DNA using Polymerase Chain Reaction (PCR) and appropriate primers. Moreover, knowledge and awareness of the local people community in the area about the disease and the vector was surveyed using a questionnaire. Population densities of the sandflies inversely was proportional to the rainfall and sandfly populations almost disappeared with heavy rainfall. The sandfly population densities seemed to have no association with the mean monthly temperature. Male sandflies outnumbered females, approximately by 100:3 in all the study sites. Both sexes were active from dusk to dawn and females tend to feed on a blood meal during the dawn in the studied area. All the samples analysed were PCR negative for leishmania DNA. The quetionnaire data showed that knowledge about the disease and the vector in the villagers is poor.
