Diagnostic exercise. Cerebral mass in a puppy with respiratory distress and progressive neurologic signs.

A 5-month-old mongrel puppy with a history of respiratory disease presented with progressive neurologic dysfunction. Hematologic results included leukocytosis (neutrophilia with a left shift) and lymphopenia. A mass in the right forebrain, identified by magnetic resonance imaging, was biopsied during decompressive craniectomy. The histologic diagnosis was granulomatous meningoencephalitis with intralesional amoebae. The dog died within 24 hours of surgery. At necropsy, a well-demarcated granuloma was confined to the cerebrum, but granulomatous pneumonia was disseminated through all lobes of the lung. Concurrent infections included canine distemper, canine adenoviral bronchiolitis, and oral candidiasis. Canine distemper virus probably caused immunosuppression and increased susceptibility to secondary infections.

Schistosomes and Microfilarial Parasites in Magellanic Penguins.

The Magellanic Penguin ( Spheniscus magellanicus) is native to Argentina, Chile, and the Falkland/Malvinas Islands, and is a regular winter migrant in Uruguayan and Brazilian coastal waters. The species is known to be susceptible to a variety of gastrointestinal nematodes, cestodes, trematodes, and acanthocephalans, as well as renal trematodes and pulmonary nematodes. Schistosomes (Platyhelminthes, Trematoda, Schistosomatidae) and microfilariae (Nematoda, Secernentea, Onchocercidae) were histologically identified in Magellanic Penguins ( Spheniscus magellanicus) that died while under care at rehabilitation centers in southern Brazil. Phylogenetic analysis of the COI gene, ITS-1 region, 5.8S rRNA gene, ITS-2 region, and 28S rRNA gene sequences of the schistosome revealed that it is closely related to, but distinct from, a schistosome reported from the African Penguin ( Spheniscus demersus). The schistosomes from Magellanic and African Penguins were grouped with Gigantobilharzia huronensis, Gigantobilharzia melanoidis, and Dendritobilharzia pulvurenta; however, the lack of a clearly monophyletic origin precludes determining their genus. The incidental discovery of novel parasites during a study that did not specifically aim to investigate the occurrence of helminths underscores the value of histopathological examination as an exploratory diagnostic approach.

Granulomatous nephritis in psittacines associated with parasitism by the trematode Paratanaisia spp.

Trematodes belonging to the family Eucotylidae are parasites of the kidney and ureter, and affect several bird species. However, psittacines have not been identified as hosts of these parasites. Three birds, an adult female blue and gold macaw (Ara ararauna), an adult female blue-winged macaw (Propyrrhura maracana) and an adult male white-eared parakeet (Pyrrhura leucotis) were admitted at the Veterinary Hospital of the Fundação Zoo-Botânica de Belo Horizonte, Brazil (FZB/BH). All three birds had severe dehydration and cachexia. The blue and gold macaw presented with dyspnea, apathy, and incoordination. Blood cell counts indicated discrete anemia and leucopenia. Blood biochemistry revealed significant increase in levels of uric acid (61 mg/dl) and blood urea nitrogen (22 mg/dl). The bird died within 24 h after admission. The other two birds were admitted with similar clinical signs, but died prior to a complete clinical examination. At the necropsy, in all the three birds, the kidneys were enlarged with brown-yellowish discoloration and irregular cortical surface. On the cut surface, there was a brown-yellowish material with few visible parasites flowing out of the parenchyma. When fragments of the kidneys were placed in 10% formalin, a large number of trematodes came out of the renal parenchyma. The parasites were identified as Paratanaisia robusta infecting all three birds, and P. bragai infecting the blue-winged macaw and the white-eared parakeet. Histologically, there was an interstitial, multifocal to coalescent, lymphoplasmacytic infiltrate with some epithelioid macrophages, and a few heterophils, characterizing a granulomatous nephritis. Adult worms and eggs were observed within dilated tubules and in the renal pelvis. In the blue and gold macaw, some parasite eggs were located interstitially associated with an intense adjacent granulomatous reaction.

Mammomonogamus infection in a human. Report of a case.

Infection of humans by Mammomonogamus is rare, with approximately 80 cases reported in the literature. When present in man, the worms cause violent coughing until their removal. The diagnosis of Mammomonogamus infection in the past has been based on morphologic characteristics of intact adults. We report a case diagnosed by features of the worms in histologic section.

Recovery of intact male and female Dipetalonema streptocerca from man.

When attempts at teasing adult Dipetalonema streptocerca free from biopsy specimens of human skin proved futile a digestion procedure was initiated. Punch biopsy specimens fixed in Michel's solution (ammonium sulfate) were incubated at 25 degrees C for 3 days in a 1.0% solution of collagenase in tris-HCl buffer. Intact worms were carefully teased out of the digested collagen and camera lucida drawings and measurements were then possible. This marks the first description of intact D. streptocerca adults recovered from man.

Micronema in man: third fatal infection.

Micronema, normally free-living in soil and humus, rarely invades and reproduces in the central nervous system, kidneys, lungs, maxillae and nasal cavity of equines. Two Micronema infections causing fatal meningoencephalomyelitis in man have been reported from Canada and Texas. Here we report a third infection in a 54-year-old black man, resident of Washington, D.C., who probably acquired the infection from decubitus ulcers. The worms in this patient were in the liver, heart and brain. The Micronema species was not identified.

Laboratory and field evaluation of a direct filtration technique for recovery of schistosome cercariae.

The use of cercariometry in epidemiological studies has been limited by turbidity, difficulty of recovering cercariae at low concentrations in natural waters, and by complex apparatus that requires a power source. The technique of differential filtration developed by Theron has been modified and tested in the laboratory and in the field in Upper Egypt for detection of Schistosoma haematobium cercariae. A recovery filter with a pore size of 30 micrometer was found to give the best results. The recovery rate in the laboratory was 51% on filtration of 5-liter samples of formalin-treated water, and 19-30% with 10- and 20-liter samples. This moderate efficiency is offset by simplicity of the technique, rapid filtration, and ease of reading the recovery filter, permitting sampling of large volumes of water in the field by persons with little training. Average densities of 0.024 cercariae per liter of water were found at the Nile and 0.029 cercariae per liter in the irrigation canals. Most cercariae were recovered between 0.700 and 0900 hours.

Hepatic granuloma due to a nymph of Linguatula serrata in a woman from Michigan: a case report and review of the literature.

There have been seven cases of human infection by nymphs of Linguatula serrata reported from the United States. Only three of these, however, are proven to be autochthonous. We report a rare case of hepatic granuloma due to a nymph of L. serrata in a woman from Michigan. She had never left the continental United States.

Infection of man by Dirofilaria repens.

Dirofilaria repens, a natural parasite of dogs and cats in Europe, Asia, and Africa, sometimes infects man. In man the worms are usually in subcutaneous tissues or in the orbit. A case is herein reported in which a non-gravid, adult Dirofilaria, probably D. repens, was in the subcutaneous tissue of a resident of Wisconsin. The patient, however, acquired the infection 8 years previously in Greece.

Eosinophilic meningoencephalitis due to Angiostrongylus cantonensis as the cause of death in captive non-human primates.

Fatal eosinophilic meningoencephalitis due to Angiostrongylus cantonensis is reported in captive non-human primates. A howler monkey (Alouatta caraya) at the Audubon Park and Zoological Gardens, New Orleans, LA, died 21 days after initial clinical symptoms. A white-handed gibbon (Hylobates lar) died at the Ardastra Gardens and Zoo, Nassau, Bahamas, 17 days after onset of symptoms. Both had access to free-ranging gastropods within the zoos. These are the first reported cases of natural infection by A. cantonensis in non-human primates in the western hemisphere.

Etiology of acute diarrhea among United States military personnel deployed to South America and west Africa.

A study of acute diarrhea was conducted from 1985 to 1987 among U.S. military personnel participating in routine shipboard exercises in South America and West Africa and ground troops deployed to coastal Ecuador. An enteropathogen was identified in 146 (51%) of 289 acute cases of diarrhea. Enterotoxigenic Escherichia coli, found in 50 (17%) patients with diarrhea, was the most commonly identified enteropathogen. Viral enteropathogens were also found in a high percentage of acute cases of diarrhea: rotavirus was detected in 11% of the patients and Norwalk virus infection in 10%. Most enteric pathogens were acquired in equal frequencies in South America and West Africa, except for rotavirus infection which was identified more often in West Africa and enteroaggregative E. coli infection which was identified more often in South America. Bacterial enteropathogens were frequently resistant to trimethoprim/sulfamethoxazole, but no resistance to quinolone drugs was observed, indicating that quinolone drugs have become important agents for the treatment of diarrhea in South America and West Africa.

Habitat and reproductive behavior of Trichinella spiralis.

The normal niche of Trichinella spiralis adults was found to be in the epithelial layer of the mucosa of the small intestine of its host. Most worms were found in the epithelium at the base of the villi and in the glandular crypts. Copulation and insemination occurred between 30 and 32 hr postinfection, all although these acts were never observed, it was concluded that copulation and insemination took place in the epithelial layer of the mucosa. A majority of the adults were found to be completely embedded in the epithelium during the deposition of the motile larvae. Motile larvae were deposited in this location and from there migrated through the stroma to venules and lymphatic vessels. Male T. spiralis were found to be capable of inseminating at least 4 females.

Hepatitis associated with a Sarcocystis canis-like protozoan in a Hawaiian monk seal (Monachus schauinslandi).

A Hawaiian monk seal (Monachus schauinslandi) died in captivity at the National Marine Fisheries Service, Kewalo Basin Facility in Honolulu, Hawaii. The animal was icteric, and the liver was friable. Microscopic lesions were detected in the colon and liver. Colonic lesions included multifocal, necrohemorrhagic colitis associated with gram-negative bacilli. The liver lesions included random hepatic necrosis and cholestasis. Asexual stages of a Sarcocystis canis-like apicomplexan were detected in hepatocytes. The parasite divided by endopolygeny. Merozoites occasionally formed rosettes around a central residual body. Ultrastructurally, merozoites lacked rhoptries. This is the first report of S. canis infection in M. schauinslandi, which is an endangered pinniped in U.S. waters.

Disseminated toxoplasmosis in magpie geese (Anseranas semipalmata) with large numbers of tissue cysts in livers.

Fatal disseminated Toxoplasma gondii infection was diagnosed in 2 captive magpie geese (Anseranas semipalmata) from a zoo in Texas. Both geese died suddenly, without apparent clinical signs. Lesions associated with T. gondii tachyzoites were seen in lungs, pancreas, liver, adrenals, bursa of Fabricius, spleen, brain, and kidneys. Toxoplasmic pneumonia and hepatitis were considered to be the primary cause of death. An unusual feature was the presence of numerous tissue cysts in hepatocytes of both geese. The diagnosis was confirmed immunohistochemically. Antibodies to T. gondii were found in 2 of 11 other geese from the zoo examined using the modified agglutination test. This is the first report of T. gondii infection in magpie geese (Anseranas semipalmata).

Larval parasites in lymph nodes of slaughter cattle.

Between 1977 and 1989, evidence of parasitic infection was found in lymph node sections of twelve cattle (0.5 per cent of lymph nodes) submitted by Canadian federal meat inspectors under the tuberculosis eradication program. Macroscopically, all lesions were green foci of various sizes; microscopically, parasitic larvae were surrounded by a wide zone of eosinophils. Nine larval parasites were identified in mesenteric and one parasite in an unidentified lymph node(s). Although rare, such lesions must be defined in order to differentiate them from other aetiologies such as mycobacterial and sarcocystic granulomas.

Myositis and death in bobwhites, Colinus virginianus (L.), due to hemorrhagic cysts of a haemosporozoan of undetermined taxonomic status.

An epizootic of myositis and death in pen-reared bobwhites occurred at a hunting club in California. The myositis was caused by myriads of elongate protozoan cysts. The cysts were in various stages of development and when mature, contained spherical zoites 1 micron in diameter. Sinuous compartments were present in all cysts. The walls of the compartments were composed of a material similar to the cyst walls. Mature cysts were filled with blood. The histologic and ultrastructural morphology of the parasite revealed the parasite to be a haemosporozoan. The parasite has numerous similarities to both Akiba caulleryi (Mathis and Leger, 1909) and organisms that cause aberrant leucocytozoonosis in other species of birds. Further studies are needed to determine if the parasite is a part of the normal parasite fauna of quail or if it represents a parasite in an aberrant host.

Toxoplasmosis in Atlantic bottle-nosed dolphins (Tursiops truncatus).

A female Atlantic bottle-nosed dolphin (Tursiops truncatus) and her calf were found beached on Picnic Island in Tampa Bay, Florida, USA. Despite therapy the animals died. Necropsy revealed severe pneumonia and lymphadenopathy in the mother and the calf, gastric ulcers and infection with the stomach digenean Braunina cordiformis in the mother, and a large, pale liver in the calf. Toxoplasma gondii was identified by light and electron microscopy and by immunohistochemistry in tissues of both animals. Toxoplasma gondii was associated with interstitial pneumonia, necrotizing adrenalitis, and cardiac myonecrosis in the mother and with lymphoid necrosis in both dolphins. The source of infection and the relationship to the recent dolphin beachings along the eastern seacoast of North America are unknown. This is the first report of toxoplasmosis in cetaceans.

Mortality of captive tortoises due to viviparous nematodes of the genus Proatractis (Family Atractidae).

Between September 1982 and January 1984, verminous colitis was diagnosed post mortem in eight red-footed tortoises (Geochelone carbonaria) and three leopard tortoises (Geochelone pardalis) from the reptile collection of the National Zoological Park. This represented 69% of 16 tortoise necropsy accessions for that period. Etiology was determined to be a viviparous pinworm-like nematode of the genus Proatractis (Family Atractidae). Clinical signs were either nonspecific, consisting of anorexia, lethargy, and depression, or were absent. Limited trials with piperazine citrate and fenbendazole appeared to be ineffectual against the parasite and supportive therapy was unsuccessful. Post mortem examination revealed roughening and thickening of the mucosa of the cecum and colon, and in severe cases myriads of tiny (0.5-1.0 cm) nematodes were evident on the mucosal surface. In six tortoises, worms were found also in the small intestine. Histopathologic features in severe cases included mucosal necrosis with parasites and mixed inflammatory cells extending into the tunica muscularis. Focal to diffuse lymphoplasmacytic infiltrates were present consistently in the submucosa of the cecum and colon, and similar but milder lesions occasionally occurred in the small intestine.

Fatal toxoplasmosis in free-ranging endangered 'Alala from Hawaii.

The 'Alala (Corvus hawaiiensis) is the most endangered corvid in the world, and intensive efforts are being made to reintroduce it to its former native range in Hawaii. We diagnosed Toxoplasma gondii infection in five free-ranging 'Alala. One 'Alala, recaptured from the wild because it was underweight and depressed, was treated with diclazuril (10 mg/kg) orally for 10 days. Antibodies were measured before and after treatment by the modified agglutination test (MAT) using whole T. gondii tachyzoites fixed in formalin and mercaptoethanol. The MAT titer decreased four-fold from an initial titer of 1:1,600 with remarkable improvement in physical condition. Lesions of toxoplasmosis also were seen in two partially scavenged carcasses and in a third fresh intact carcass. Toxoplasma gondii was confirmed immunohistochemically by using anti-T. gondii specific serum. The organism was also cultured by bioassay in mice from tissues of one of these birds and the brain of a fifth 'Alala that did not exhibit lesions. The life cycle of the parasite was experimentally completed in cats. This is the first record of toxoplasmosis in 'Alala, and the parasite appears to pose a significant threat and management challenge to reintroduction programs for 'Alala in Hawaii.

Chronic upper respiratory tract disease of free-ranging desert tortoises (Xerobates agassizii).

Seventeen desert tortoises, Xerobates agassizii, with upper respiratory tract disease were examined; thirteen were euthanatized for necropsy. Four normal control desert tortoises from a clinically healthy population were similarly evaluated. Hemoglobin and phosphorus values were significantly (P less than or equal to 0.05) lower and serum sodium, urea, SGOT, and cholesterol values were significantly higher in ill tortoises compared to controls. No significant differences in concentrations of serum or liver vitamins A and E were found between the two groups. While no significant differences were found for concentrations of lead, copper, cadmium, and selenium, the livers of ill tortoises had higher concentrations of mercury and iron. Lesions were found consistently in the upper respiratory tract (URT) of ill tortoises. In all ill tortoises dense infiltrates of lymphocytes and histiocytes obscured the mucosal epithelium and underlying glands. The mucosal epithelium was variably dysplastic, hyperplastic, and occasionally ulcerated. Electron microscopic studies revealed small (350 to 900 nm), pleomorphic organisms resembling Mycoplasma sp., in close association with the surface epithelium of the URT of ill tortoises. Pasteurella testudinis was cultured from the nasal cavity of all ill tortoises and one of four control tortoises. A Mycoplasma sp. was cultured from the nasal passageways of four ill tortoises and was ultrastructurally similar to the pleomorphic organism present on the mucosa in tissue section.