Isolation and identification of intestinal bacteria from Japanese tree frog (Hlya japonica) with the special reference to anaerobic bacteria.

The bacteria in the large intestines of eight Japanese tree frogs (Hlya japonica) were enumerated by using an anaerobic culture system. The microorganisms at approximately 3.1 x 10(9) bacteria per g (wet weight) of intestinal contents were present in the intestine of all the frogs tested. No difference of the total bacteria in the frog intestine was observed between two different incubation-temperatures (room temperature and 37 degrees C). Eleven genera and 16 species were isolated from the frog intestine. In most frogs, Bacteroides (B.) caccae and B. vulgatus were detected as the predominant organisms. Escherichia coli was also present in greater numbers in the intestine. Other bacteria isolated at high dilutions were strict anaerobes, including Fusobacterium and Clostridium. Enterococcus faecalis was frequently isolated from the frog intestine. However, four genera of Bifidobacterium, Eubacterium, Peptostreptococcus, and Lactobacillus were not isolated from the frog intestine.     

Experimental studies on the life-cycle of Sebekia wedli (Pentastomida: Sebekidae)

Four young Nile crocodiles (Crocodylus niloticus) were infected with infective pentastome larvae obtained from naturally infected Mozambique bream, Oreochromis mossambicus, and red-breasted bream, Tilapia rendalli swierstrai in the Kruger National Park. At day 95 post infection one of the crocodiles died and three female and four male S. wedli were recovered from its lungs. One pair was found in copula but the uteri of the females were not yet developed. Males and females were of about equal size. After 226 d post infection the three remaining crocodiles were sacrificed. Two of these harboured no pentastomes but eight were taken from the lungs of the third. The sex ratio had shifted in favour of the females, seven females and one male being present. One of the females recovered from the crocodiles was placed in saline and produced 3,400 eggs. These were used to infect eight guppies, Poecilia reticulata. Within 31 d two infective stages of S. wedli had developed in one of the guppies thus completing the life-cycle of the pentastome. S. wedli recovered from experimentally infected final hosts were slightly smaller than those recovered from a wild-caught final host.     

大肠杆菌K_(88ac)与LT(A~-B~ )抗原基因质粒在猪霍乱沙门氏菌弱毒株中的表达

应用细菌质粒转化技术,将大肠杆菌K_(?)与LT(A~-B~ )抗原基因重组质粒转入猪霍乱沙门氏菌弱毒菌苗株中.对获得的其中8个转化子进行鉴定的结果表明,转化的细菌仍保持沙门氏菌的形态、生化及抗原特性,同时可稳定地表达K(?)和LT-B两种抗原.用微量间接血凝试验、抗甘露糖豚鼠红细胞凝集试验(MRHA)、ELISA等对转化菌表达的K(?)抗原进行了测定,用间接免疫溶血试验对其表达的LT-B抗原进行了测定.结果,这两种抗原在转化的细菌中均可高效表达.电镜下观察,转化的细菌在其表面形成菌毛样结构.这种转化细菌表现出猪霍乱沙门氏菌与产肠毒素性大肠杆菌的两种抗原特性,为这种双价工程菌苗的研制提供了有价值的候选菌株.本研究结果还表明,猪霍乱沙门氏菌弱毒菌苗株可作为基因转化的有效受体菌.     

Disseminated Mycobacterium avium subsp. avium infection in a Captive Richardson's Ground Squirrel (Spermophilus richardsonii)

Although mycobacteria have been isolated from rodents, overt mycobacteriosis is rare in any rodent species. A pet adult male Richardson's ground squirrel (Spermophilus richardsonii) died after a short course of alopecia, anorexia, and weight loss. Necropsy and subsequent histopathological examination of tissue samples revealed disseminated granulomatous inflammation involving the lungs, lymph nodes, liver, intestine, adrenal gland, spleen, pleura, and peritoneum. Ziehl-Neelsen stain revealed high numbers of acid-fast bacilli within the cytoplasm of macrophages and multinucleated giant cells. Polymerase chain reaction performed on paraffin-embedded tissues was positive for Mycobacterium avium subsp. avium and negative for M. bovis-tuberculosis complex. Three females housed with this squirrel remained clinically healthy, and mycobacterial cultures of pooled feces from these animals were negative. To the authors' knowledge, this is the second report of disseminated mycobacteriosis in squirrels involving M. avium subsp. avium, with both cases described recently in the Iberian Peninsula.     

A neonatal calf with concurrent meningoencephalitis by Enterobacter cloacae and enteritis by attaching and effacing Escherichia coli (O128)

A neonatal calf developed nervous symptoms followed by diarrhea. The principal pathological changes were fibrinopurulent meningitis with necrosis of the cerebral parenchyma, and attaching and effacing lesions in the intestine. Cerebral necrosis was frequently associated with vascular changes. Enterobacter cloacae was isolated from the brain and Escherichia coli (O128) from the intestinal content. These suggest that cerebral and intestinal lesions were caused by the isolated organisms, and that most necrosis of the cerebral parenchyma might be infarctive.     

Hemorrhagic bowel syndrome in dairy cattle: 22 cases (1997-2000)

OBJECTIVE: To determine signalment, history, and clinical, necropsy, and microbiologic findings in dairy cows with hemorrhagic bowel syndrome. DESIGN: Retrospective study. ANIMALS: 22 adult dairy cows from a single farm in Colorado. PROCEDURE: Medical records were reviewed for information on signalment, medical and reproductive history, the owner's chief complaints, results of physical examinations and ancillary diagnostic tests, treatment and response to treatment, results of microbiologic testing, and, if applicable, postmortem findings. RESULTS: Common clinical signs were acute signs of profound depression, decreased milk production, tachycardia, ruminal stasis, abdominal distention, and dark clotted blood in the feces. Rectal examination revealed distended loops of small intestine in 7 of 14 cows. Transabdominal ultrasonography revealed small intestinal ileus and distention in 12 of 12 cows and homogeneous echogenic intraluminal material compatible with intraluminal hemorrhage and clot formation in 4. Seven of 8 cows treated medically died; 9 of 13 cows that underwent surgery died or were euthanatized. Clostridium perfringens was isolated from fecal samples from 17 of 20 cows. The most common morphologic diagnosis at necropsy was severe necrohemorrhagic enteritis or jejunitis with intraluminal hemorrhage or blood clots. The most prominent histologic finding was severe, segmental submucosal hemorrhage and edema of the small intestine. CONCLUSIONS AND CLINICAL RELEVANCE: Results confirm that in adult cattle, hemorrhagic bowel syndrome is a sporadic acute intestinal disorder characterized by intraluminal hemorrhage and obstruction of the small intestine. Clostridium perfringens was consistently isolated from the feces of affected cows. The prognosis for affected cows was grave.     

Bacterial colonization and morphology of the intestine in porcine Escherichia coli enterotoxemia (edema disease)

Twenty-one pigs were divided into three groups. Pigs in one group were inoculated with the intestinal contents which included bacteria from a pig with edema disease. Pigs in another group were inoculated with a culture of Escherichia coli serogroup O 139:K12(B):H1 isolated from the aforementioned contents, and pigs in a third group served as uninoculated controls. The infection was similar following both inocula. Enterotoxemia developed in 11 of the 14 pigs allowed to survive for more than two days. The onset varied from two to seven days after inoculation. There were maximal viable counts of E. coli in the intestine from the second day post-inoculation and thereafter. In frozen and paraffin sections, as well as by scanning electron microscopy, the organisms were seen on the surface of the small intestinal epithelium where they formed either isolated colonies or continuous layers. They colonized the lower small intestine more intensely than the upper section. The intestinal epithelium and the villi of infected pigs were indistinguishable morphologically from the tissues of three uninoculated control pigs. The diarrhea which was observed in controls and inoculated pigs before inoculation and the villus atrophy in controls and inoculated pigs indicated a preexisting infection with at least one other agent.     

Histology of uterine leiomyoma and occurrence in relation to reproductive activity in the Baltic gray seal (Halichoerus grypus)

A high prevalence of uterine leiomyoma has been reported in Baltic gray seals aged 15 years and above. Studies on Baltic seals during the 1970s revealed high tissue concentrations of the organochlorines bis(chlorophenyl)-1,1,1-trichloroethane (DDT) and polychlorinated biphenyls (PCBs), lowered reproduction rate, and pathologic changes. In the second half of the 1970s, decreases of PCB and DDT in Baltic biota occurred, and the prevalence of pregnancies in Baltic seals increased. Between 1975 and 1997, 53 Baltic gray seal females of age 15-40 years were found dead and sent to the Swedish Museum of Natural History. Seals were autopsied and 34/53 (64%) had uterine leiomyomas. Samples from 15 were sufficiently well preserved for histologic examination. Uterine leiomyomas were found most commonly in the uterine corpus but also were observed in the uterine horns, cervix, and vagina. Cut surfaces of the leiomyomas appeared as whorled white fibrous tissue. Histologically, spindle cells were arranged in a whorl-like pattern. The nuclei were rod-like and strikingly uniform in shape and size. Mitotic figures were rare. Immunohistochemical staining of the tumors showed a positive reaction to antibodies recognizing smooth muscle actin. Reproductively active gray seals have an ovarian corpus luteum or albicans for most of the year. In 22/34 (65%) gray seals with uterine leiomyomas, ovaries did not contain corpora. In gray seals without macroscopically detected uterine leiomyoma, ovaries from 6/19 (32%) seals had no corpora. It is possible that the development of leiomyoma in the seals is associated with organochlorines and the previous low reproductive activity.     

Description of Pelonia africana n. g., n. sp. (Pentastomida: Sebekidae) from the lungs of Pelomedusa subrufa and Pelusios sinuatus (Chelonia) in South Africa

The terrapins Pelomedusa subrufa and Pelusios sinuatus taken from a water reservoir in the Northern Province, South Africa, were examined for pentastome infections. Two immature specimens, a patent female and a mature male, were obtained from the lungs of four hosts, each of which harboured a single specimen. Based on the morphology of the specimens the new monospecific genus, Pelonia africana n. g., n. sp., is described. It is characterized by smooth, dorsally convex hooks with sharply bent blades. The oral cadre is more or less U-shaped. Delicate chitinous fibres, which can be difficult to see, connect the lateral prongs anteriorly. In this, as well as the morphology of the copulatory spicules, it is most like Sebekia wedli. The latter, however, possesses spinous hooks, which are absent in P. africana. The hooks are slightly and the copulatory spicules markedly larger in P. africana than in S. wedli. The lack of a double-hooked collar at the terminal end of the cowry-shell shaped base of each copulatory spicule and the absence of a peg-like extension of the oral cadre into the oesophagus, distinguishes P. africana from members of the genus Alofia. The oral cadre of the South American species Diesingia megastoma, from aquatic chelonians, is more than twice the size than that of Pelonia and there is a distinct difference in shape. The hooks of the genus Diesingia are flat-topped, and both the anterior as well as the posterior fulcra carry cowl-like extensions. The number of annuli, 55-60 in D. megastoma and approximately 30 in P. africana, further separates the two genera. The most striking feature of Diesingia which sets it apart from Pelonia and the other genera of the family Sebekidae, is the configuration of its copulatory spicules. Pelonia and Diesingia share morphological features with all the other sebekiids, but it is the unique combination of diagnostic characters that separates the two genera from those, as well as from each other.     

Pathology of naturally occurring paratuberculosis in water buffaloes (Bubalus bubalis)

Gross and histologic lesions of paratuberculosis were studied in water buffaloes. Small intestines and associated mesenteric lymph nodes of 405 water buffaloes were examined. Of these, 20 animals having visible changes of intestinal thickening, mucosal corrugations, and enlargement of mesenteric lymph nodes exhibited histologic alteration characteristics of mild to moderate granulomatous inflammation. The histologic lesions observed in these animals were classified into 3 grades on the basis of type of cellular infiltration, granuloma formation, and presence of acid-fast bacilli. Grade-1 lesions observed in 8 animals were marked by the presence of scattered epithelioid macrophages amid large number of lymphocytes in the intestinal villi and in the paracortical regions of the associated mesenteric lymph nodes. Another 8 animals classified under grade-2 revealed microgranulomas, infiltration with a larger number of epithelioid macrophages besides lymphocytes in the intestinal villi, and granulomas in the mesenteric lymph nodes. Grade-3 lesions observed in 4 animals were characterized by the presence of epithelioid granulomas and giant cells in the intestines and the mesenteric lymph nodes. The Ziehl-Neelsen's stained tissue sections revealed acid-fast bacilli in grade-3 and -2 animals and acid-fast granular debris in grade-1 animals. Among these 20 buffaloes, 14 (70%) were positive in the IS900 specific polymerase chain reaction and 6 (30%) were positive in the bacterial culture.     

Proliferative enteritis in leopard geckos (Eublepharis macularius) associated with Cryptosporidium sp. infection.

Twenty-three leopard geckos (Eublepharis macularius) with various clinical histories of weight loss, anorexia, lethargy, and diarrhea were submitted either intact or as biopsy specimens to the University of Florida Anatomic Pathology Service. Gross necropsy findings in the intact geckos included marked reduction of subcutaneous adipose tissue stores at the tail base and mild thickening and reddening of the small intestine. Histologic examination revealed Cryptosporidium sp. infection associated with hyperplasia and mononuclear inflammation of the small intestine in all geckos. Parasites and lesions were only rarely observed in the stomach and large intestine of geckos. The histologic and ultrastructural lesions in the small intestine of leopard geckos infected with Cryptosporidium sp. have not been well characterized previously. This report implicates Cryptosporidium sp. as the cause of disease in the geckos and describes the range of histologic lesions observed.     

Neospora caninum is a cause of perinatal mortality in axis deer (Axis axis)

Neospora caninum is a worldwide distributed protozoan that may cause neuromuscular disease in dogs and reproductive failure in domestic and wild ruminants. One axis fawn (Axis axis) and four neonates from the same deer herd died at a zoo in Argentina within a four-month period. The fawn presented with dilatation of the anal sphincter at birth and incontinence, developed weakness and ataxia and died at 14 days of age. At necropsy, a mega formation of the distal large intestine was observed. Microscopically, non-suppurative encephalitis, suppurative bronchopneumonia, fibrin necrotic enteritis and degenerative changes in the liver were observed in hematoxilin and eosin-stained tissue sections, and thick-walled N. caninum-like cysts were observed in fresh brain samples. Serologic studies for N. caninum revealed an IFAT titer of 1:6400 in the fawn and 1:25, 1:400, 1:3200 and 1:6400 in the neonates. N. caninum DNA was detected in brain samples from the fawn and from one neonate by PCR, and the parasite was isolated in vitro from the fawn’ brain after passage through gerbils (Meriones unguiculatus) and gamma-interferon knock-out mice. N. caninum DNA obtained from the fawn, neonate and isolated parasites showed the same microsatellite pattern. This suggests a common infection source for both animals.The diagnosis of N. caninum infection was confirmed, suggesting its association with perinatal mortality in captive axis deer. To the best of our knowledge, this is the first report of clinical disease associated to N. caninum infection in axis deer and of isolation of the parasite from this wild ruminant species.     

Testicular changes observed in boars following experimental inoculation with pseudorabies (Aujeszky''s) virus.

Four boars were inoculated intranasally with pseudorabies virus to determine if microscopic testicular changes occurred as a result of infection. Testicular biopsies and semen samples were taken at two, four and six weeks postinoculation and the boars were castrated immediately after the last sample collection. Testicular samples and semen were cultured to determine if the virus was present. Pseudorabies virus was not isolated from the semen or testicular tissue. Virus was isolated from trigeminal ganglia at necropsy and from nasal swabs taken one day after castration. Consequently, a time of high risk for shed of the virus from clinically normal carrier animals is immediately following castration. Gross changes were not observed in testicular tissues and microscopic changes in the testicles were the result of biopsy. Lesions consistent with pseudorabies virus infection were observed in the central nervous system of all inoculated boars. Temporary lowered fertility may result from the effects of elevated body temperature on spermatogenesis during acute clinical disease. However, it appears that the strain of pseudorabies virus used, lacked the ability to infect and/or replicate in the boars' reproductive tracts.     

Aortic onchocercosis and elaeophorosis in traditional TSZ-cattle in Tabora (Tanzania): prevalence and pathology

Onchocerca armillata was found in 3838 (95.4%) and Elaeophora poeli in 70 (1.7%) out of 4025 samples of aortas collected from cattle slaughtered at Tabora in Tanzania during the calendar year 1988. Gross lesions of the affected aortas varied from mild to severe, characterised by parasitic tunnels, nodules and corrugated calcified ridges on the aortic wall. Histological sections revealed changes as a result of tissue reaction against the parasites which were embedded into the intima of affected aortas. Calcification and hyaline degeneration were common features. The high prevalence of O. armillata and the extensive pathological lesions observed would seem to warrant assessment of the importance of onchocercosis in animal production in the tropics. Meanwhile, further studies are required to elucidate the epizootiology of aortic onchocercosis and elaeophorosis in order to devise practicable diagnosis, treatment and control methods.     

Species composition of Gasterophilus spp. (Diptera, Oestridae) causing equine gastric myiasis in southern Italy: parasite biodiversity and risks for extinction

Horse gastrointestinal myiasis caused by larvae of Gasterophilus spp. (Diptera, Oestridae) flies has a worldwide distribution and, where present, it is primarily caused by larvae of Gasterophilus intestinalis and Gasterophilus nasalis. Other species, i.e., Gasterophilus inermis, Gasterophilus pecorum and Gasterophilus haemorrhoidalis, present in different or in the same regions of the gastrointestinal tract, were only occasionally reported in very limited areas of eastern European Countries and in central Italy. With the aim to contribute data on the species composition of Gasterophilus and on the seasonal variation of the infection pattern in southern Italy, 152 native horses were necropsied from January to December 2003 and Gasterophilus larvae were collected from the stomach, the small intestine and the rectum of each of them. On the whole, 125 (82.2%) horses were infected by larvae of Gasterophilus spp. and 214 second stage larvae (L2) and 13,342 third stage larvae (L3) collected. Five species of Gasterophilus were identified with the following prevalence: G. intestinalis=95.2%, G. nasalis=44.8%, G. inermis=15.2%, G. pecorum=2.6% and G. haemorrhoidalis=0.8%. L3 were retrieved throughout the observation period with the highest mean burdens from January to August 2003 while the lowest mean was registered from September to November 2003. L2 were collected in February-March 2003 and from September to December 2003. The majority of the animals (n=66, 43.4%) were infected with a single Gasterophilus species, however, 45 animals (29.6%) harboured 2 species, 12 animals (7.9%) 3 species and 2 animals (1.3%) 4 species. The trend of abundance in the L3 of G. intestinalis and G. nasalis, the most represented species, was highly concordant (r=0.5, p<0.001). A retrospective comparison of our results and of other data from four seasons of observation (1983-1986) in central Italy showed that the number of G. inermis, G. pecorum and G. haemorrhoidalis have been decreasing relative to G. intestinalis and G. nasalis which may suggest tendency toward the extinction of the three former species of Gasterophilus.     

Study on the prevalence of Toxoplasma gondii and Neospora caninum and molecular evidence of Encephalitozoon cuniculi and Encephalitozoon (Septata) intestinalis infections in red foxes (Vulpes vulpes) in rural Ireland

Thoracic fluid (pleural fluid and clotted blood) from 206 foxes were examined for antibodies to Toxoplasma gondii and 220 thoracic fluid samples were tested for Neospora caninum antibodies using indirect immunofluorescent antibody tests (IFAT). A total of 115 (56%) and six (3%) foxes had antibodies to T. gondii and N. caninum, respectively. The brains from 148 foxes were examined for histological lesions and pathological changes suggestive of parasitic encephalitis were observed in 33 (22%). Two thirds of these foxes had antibodies to T. gondii and one fox had antibodies to both T. gondii and N. caninum. PCR assays carried out on DNA extracted from the 33 brains with histological lesions were negative for N. caninum but one of the brains was positive for T. gondii. Microsporidian DNA was also amplified from the brains of two of these foxes. Sequencing these amplicons revealed 100% homology with Encephalitozoon (Septata) intestinalis in one fox and Encephalitozoon cuniculi in the second fox. This is the first report of Encephalitozoon infections in wildlife in Ireland.     

Characterization of the host response in systemic isosporosis (atoxoplasmosis) in a colony of captive American goldfinches (Spinus tristis) and house sparrows (Passer domesticus)

Systemic isosporosis, also known as atoxoplasmosis, is a common parasitic disease of passerines. Infection is thought to be endemic in wild birds with fulminant, fatal disease occurring under the influence of stress, concurrent infections, or immunosuppression. Here, we describe the histologic and immunohistochemical characteristics of the cellular infiltrate occurring in captive colonies of American goldfinches and house sparrows. Necropsies were performed on 9 birds, and histologic examination was performed on the intestines of 7 additional birds. Lesions were most severe in the proximal small intestines. Histologically, the changes ranged from variably intense infiltrates of lymphocytes that filled the lamina propria to sheets of large, atypical cells that expanded and obliterated normal mucosal epithelium and invaded through the wall of the intestine and into the ceolomic cavity. Both the smaller lymphocytes and large atypical cells were immunoreactive for CD3. Intracellular parasites consistent with Isospora were detected in the large atypical cells, but they were more easily detectable in the more differentiated lymphocytes. Polymerase chain reaction and virus isolation performed on tissues from 7 birds were negative for retroviruses and herpesvirus. The immunohistochemical results of this study and the destructive nature of the cellular infiltrate suggest that the lesion represents T-cell lymphoma. In birds, lymphomas are most often associated with herpes and retroviruses; the absence of these viruses suggests that the parasite initiated neoplastic transformation. Though much work needs to be done to prove the transformative nature of the lesions, these preliminary results suggest that passerine birds may be susceptible to parasite-associated lymphomas.     

中草药免疫增强剂对鸡小肠T淋巴细胞免疫组化研究

为了探讨中草药免疫增强剂的作用机理,采用组织学常规切片技术和免疫组织化学染色的方法对鸡小肠黏膜淋巴组织中T淋巴细胞的数量分布进行了动态观察.将1日龄60只健康公鸡随机分成2组,一组为对照组,另一组为试验组,试验组按1%浓度的中草药免疫增强剂饮水,连续21 d.在第14天、第21天分别取各组鸡小肠,制成组织切片,进行组织学观察.结果显示,试验组鸡小肠的T淋巴细胞数显著高于对照组(P<0.05),表明中草药免疫增强剂对鸡小肠免疫有显著的增强作用.     

Detection of Neorickettsia (Ehrlichia) risticii in tissues of mice experimentally infected with cercariae of trematodes by in situ hybridization

Neorickettsia (Ehrlichia) risticii was demonstrated to occur in cercariae developing in Juga yrekaensis snails by experimental transmission, genetic detection and histopathology. Cercariae were isolated from the digestive glands of snails collected in a fresh stream water area of Siskiyou County, CA, and inoculated into CF1 mice. Mice developed clinical signs, splenomegaly and histopathologic abnormalities. The agent was maintained by serial passages of whole blood in CF1 mice. A 527-bp product of the 16S rRNA gene of N. risticii was serially detected by nested PCR in blood, feces, salivary gland, suprarenal gland, spleen, intestine and bone marrow of inoculated mice. N. risticii DNA was detected by in situ hybridization with DIG-labeled probe in PCR-positive salivary gland, intestine and spleen tissue sections of experimental mice on day 30 after inoculation. Infection in mice was established when cercariae were inoculated by either IP or SC routes but not established following intraoral route. N. risticii was detected by PCR in spleen, intestine and bone marrow even after 73 days post-inoculation whereas blood from the same animals became negative at 58 days. N. risticii was observed by in situ hybridization in salivary gland, spleen and intestine of mice infected by IP or SC inoculation. This ISH protocol should aid investigations on the host range of the Neorickettsiosis and pathogenesis of neorickettiosis in vector, animal or human.     

The susceptibility of two species of wallaby to infection with Trypanosoma evansi

OBJECTIVE: To determine the susceptibility of the agile wallaby (Macropus agilis) and the dusky pademelon (Thylogale brunil) to infection with Trypanosoma evansi. METHOD: Two agile wallabies and three dusky pademelons were experimentally infected with between 5 x 10(4) and 10 x 10(4) T evansi from a cryopreserved stabilate isolated from an indonesian buffalo. Animals were observed twice daily for clinical signs and blood was collected every 3 days to determine parasitaemia. Necropsy was conducted on animals that died or were euthanised when in extremis and representative tissue sections examined. RESULTS: All wallabies developed a high parasitaemia by 6 days after infection, which persisted until death or euthanasia in extremis, between days 8 and 61. Clinical signs included anorexia, weakness and ataxia. Anaemia occurred in one wallaby that survived for 61 days. Gross pathological changes varied between animals. They included pericarditis, serous atrophy of fat, splenomegaly, ulcerative gastritis and enteritis. Histological changes were characterised by a mononuclear cell infiltration of the connective tissue of most organs with little cellular destruction. Striking lesions were seen in the choroid, heart, stomach and small intestine. CONCLUSION: Agile wallabies and pademelons are highly susceptible to infection with T evansi. Wallabies, therefore, have the potential to spread T evansi within New Guinea and Australia if infection is introduced. Mortality is likely to be high thereby acting as an indicator of recent introduction. Histological changes seen in wallabies infected with T evansi are diagnostic for infections occurring in Australia and Papua New Guinea.