Brain and spinal cord lesions in encephalitozoonosis in the blue fox

The central nervous system lesions in encephalitozoonosis were studied in 11 naturally infected blue foxes. Immunohistochemical staining was employed in the demonstration of the parasites and identification of host cells. Consistent findings in acute to subacute stages included granulomatous meningoencephalomyelitis and vasculitis, with arterial lesions similar to polyarteritis nodosa. Chronic stages were dominated by arteriosclerosis, perivascular mononuclear infiltrations and gliosis, with less prominent granulomatous reaction. Parasites were almost constantly observed in association with active lesions both in vessels and nervous tissue. Parasitophorous vacuoles (PV) occurred in endothelial cells and in the medial layer of arteries. Neurons, including even their processes, were widely parasitized, a fact that may account for the brain being an important target organ. PV also occurred in ependymal cells of the choroid plexus and occasionally in macrophages. A great number of parasites was demonstrated in phagolysosomes of macrophages, a fact that probably reflects a relative resistance to digestion, and may consequently contribute to the development of the prominent granulomatous reaction. It was concluded that the brain lesions, except in chronic stages of mild infections, seem to be pathognomonic for encephalitozoonosis in the blue fox.

Gastrointestinal zoonoses

Infectious gastrointestinal diseases affect man and animals throughout the world. Certain etiologic agents (for example, Salmonella spp., Campylobacter jejuni, Yersinia enterocolitica, Cryptosporidia, Strongyloides stercoralis, Echinococcus granulosa) seem to have the potential to be transmitted from pets to people, causing severe disease in the latter. Other agents seem unlikely to be transmitted but may have the potential to be zoonoses. This article discusses proved, suspected, and possible zoonotic agents that may originate from the gastrointestinal tract of dogs and cats.

A light and electron microscopic study on abomasal globidiosis in Somali goats

Abomasum from apparently healthy Somali goats with globidiosis showed pin-head sized nodules embedded in the mucosa. The nodules consisted of encapsulated cysts, containing mature or immature schizonts. Glandular atrophy and lymphohistiocytic cell reaction were often found in the vicinity of these cysts. The fine structure of immature and mature cysts is described in details. The mature cysts contained elongated, spindle shaped merozoites (type I) or shorter, ovoidal merozoites (type II). Some mature cysts also had basophilic granular bodies among the merozoites. Type I and type II merozoites were morphologically different from those earlier described in goats.

Important parasites of dover sole (Solea solea L.) kept under mariculture conditions

Dover sole (Solea solea L.) were examined for parasites at the White Fish Authority (WFA) fish farm at Hunterston, Ayrshire, Scotland. The most important parasites appeared to be the two blood-feeding ectoparasites Lernaeocera sp., a copepod, and Hemibdella soleae, an ichthyobdellid leech, and the haematoprotozoan Haemogregarina simondi. The anaemia and general malaise of the sole investigated was attributed partly to general stress and the debilitating effects of transfer from the wild into an aquaculture system and partly to the impact of the parasites observed.

Monoclonal antibody technology in the development of vaccines for livestock parasites

Vaccination against animal parasites offers an alternative to chemotherapy for the control of losses due to morbidity and mortality. However, only a few vaccines are currently available, and these are based on controlled infections with living parasites. Further advancement in the development of defined vaccines against parasite infections has been hindered by incomplete knowledge of the immunological relationship between the host and the parasite. The advent of monoclonal antibody technology has provided a powerful new tool for the identification and isolation of parasite antigens. Exploitation of this technique in veterinary parasitology has greatly facilitated progress toward the development of vaccines against several animal parasites.

Light microscopical study of Blastocystis spp. in monkeys and fowls

An investigation of a Blastocystis species obtained from several species of monkeys and fowls was conducted to clarify the morphology of the organism, using light microscopical techniques including Giemsa, Heidenhain iron hematoxylin, Trichrome stains, iodine mount and phase-contrast microscopy. A comparison was made with Blastocystis hominis from humans. Blastocystis spp. were found in 15 out of 26 monkeys and in all of 12 fowls (10 chickens and 2 ostriches) examined. The behaviour of the parasites in the bowels was also examined, using paraffin-embedded sections. Microscope examination of the lumen contents at death revealed the organism in the caecum of monkeys and fowls. The organisms from faeces, cultures and the lumen contents of the caecum of humans, monkeys and fowls were similar, except for variations in the size and contents of the central vacuoles, which occupied the centre of the organisms.

Parasitic laryngeal papillomatosis in a horse

Papillomatous lesions intruding into the laryngeal airway were identified in an imported polo pony during a routine neurological examination for partial quadriplegia. Histological examination established a diagnosis of laryngeal besnoitiosis but it is unlikely that the laryngeal parasitism was associated with the cerebellar neuropathy which was also present.

Characterization of Tritrichomonas foetus antigens, using bovine antiserum

Tritrichomonas foetus antigens were identified, using the serum of an Angus heifer that had been repeatedly immunized with suspensions of 1 X 10(8) organisms in Freund's complete adjuvant. Antibody activity against T foetus was determined by dot-blot analysis, using horse-radish peroxidase-conjugated anti-bovine immunoglobulin to detect bound antibody. The antiserum contained antibodies against surface and flagellar components of live or fixed T foetus, as determined by use of immunofluorescence. The antiserum reacted with approximately 38 proteins in a pool of 55 to 60 components resolvable by polyacrylamide-gel electrophoresis of T foetus extracts.

[A review of various parasites of rabbits]

The increased interest in breeding and production of rabbits has initiated the present work, in which a review on the occurrence, significance and control of some important parasite infections of the domestic rabbit is given. In wild rabbits parasite diseases often affect single animals, whereas the intensive production of domestic rabbits typically has to deal with parasites as herd problems which in some cases may invalidate the economy of commercial rabbitries. The most important parasite diseases of the domestic rabbit comprise coccidiosis caused by Eimeria-spp. and ear mange caused by Psoroptes cuniculi.

Production and preliminary characterization of murine monoclonal antibodies to Ichthyophthirius multifiliis, a protozoan parasite of fish

An initial panel of 34 hybridomas, each secreting antibodies reactive with an infective theront stage of an Ichthyophthirius multifiliis isolate, was produced. Three of these cell lines, each producing immunoglobulin M class antibodies, were cloned by limiting dilution and were expanded as ascites-producing tumors in syngeneic mice. Three monoclonal antibodies (MAB) reacted with intact whole theronts in an enzyme-linked immunosorbent assay to dilutions of 1:10,000 in ascitic fluids and had a similar pattern of surface and cytoplasmic staining in indirect immunofluorescent tests. Only antigen specified by MAB E6 could be characterized by acrylamide gel electrophoresis and immunoblotting; initial data indicated a molecular weight of 200,000. Physicochemical properties of the determinants recognized by the 3 MAB were tested by pronase digestion and periodate oxidation. Seemingly, a protein, glycoprotein, and carbohydrate were recognized by MAB E6, FE10, and AC8, respectively.

Seasonal and age distributions of Babesia, Hepatozoon, Trypanosoma and Grahamella species in Clethrionomys glareolus and Apodemus sylvaticus populations

Four common blood parasites belonging to the genera Babesia, Hepatozoon, Trypanosoma and Grahamella were detected in sympatric populations of Clethrionomys glareolus and Apodemus sylvaticus. Seasonal changes in the abundance of hosts and parasites were monitored in a longitudinal field survey for 18 months. All parasites in both hosts showed similar seasonal patterns with most transmission occurring in summer and autumn and ceasing in winter. Amongst aged subsets of each host population, Hepatozoon and Grahamella spp. were primarily parasites of young animals whereas Babesia and Trypanosoma spp. generally infected older hosts. Data from the aged subsets were also used to estimate values for the basic reproductive rate, R0, for each parasite. In C. glareolus, R0 = 2.0 for B. microti, 2.6 for H. erhardovae, 1.7 for T. evotomys and 2.8 for Grahamella sp. In A. sylvaticus R0 = 2.2 for Grahamella sp. These estimates are probably representative only for summer and autumn of each year.

Acquired resistance of black mollies Poecilia latipinna to infection by Ichthyophthirius multifiliis

Changes in the response of black mollies Poecilia latipinna to infection with Ichthyophthirius multifiliis subsequent to single I. multifiliis infections were examined experimentally. Incomplete resistance to infection was established, the degree of which did not depend on the intensity of the initial infection. Resistance was maintained for longer periods, however, by those fish with higher initial levels of infection. Previous experience of infection by their hosts had a significant, though small, effect on the time for which trophozoites remained on the fish. The influence of these results on the population dynamics of the Ichthyophthirius-fish interaction is examined with the aid of simple mathematical models.

Dispersal of the parasitic ciliate Lambornella clarki: implications for ciliates in the biological control of mosquitoes

Lambornella clarki (Ciliophora: Tetrahymenidae), an endoparasite of Aedes sierrensis (Diptera: Culicidae), is dispersed by infected adult mosquitoes. Invasion of the ovaries induces parasitically castrated females to exhibit oviposition behavior and thereby actively disperse ciliates through deposition into water. Oviposition behavior of infected females is prolonged and mimics that of normal gravid females in their first gonotropic cycle. Adults of both sexes also passively disperse ciliates by dying on water surfaces, and infected adults are more likely to die on water than uninfected adults. Ciliates dispersed by infected adults can infect larvae and form desiccation-resistant cysts. Parasite-induced dispersal by hosts, desiccation-resistant cysts, an active host-seeking infective stage, and high infection and mortality rates all indicate significant biological control potential for these and related ciliates against container-breeding mosquitoes.

Other parasites. Recent advances

This article briefly reviews new information on trichostrongylid stomach worms, spirurid stomach worms, tapeworms, threadworms, pinworms, intestinal protozoa, lungworms, eye worms, and numerous other aberrant parasites as it relates to prevalence, pathogenesis of diseases, and treatments.