Geology topics
Publications and source records attributed to C. M. Herman.
Hepatozoon sciuri (Coles, 1914) is reported from gray squirrels ( Sciurus carolinensis ) in Washington, D.C. and Maryland. Blood smears stained with Giemsa's stain revealed a parasitemia in 16 to 71% of the squirrels examined. A technique for laking the red cells and concentrating the white cells in blood samples demonstrated this protozoon to be present in every squirrel so tested.
The life cycle of Leucocytozoon simondi is Illustrated in a series of color photomicrographs of the various stages of development in the blackfly vector and in the tissues and blood of Anatidae. A brief discussion of the life cycle is presented and taxonomic status of the parasite is reviewed. The bibliography includes references to the stages depicted and other phases of the development, morphology and pathogenesis of .L. simondi.
A history is given of the Seney National Wildlife Refuge and the losses of goslings of Canada geese ( Branta canadensis ) recorded since inception of the refuge in 1935. Since 1960, when more reliable data became available, losses have been extensive every 4 years. Gosling deaths are attributed to the infection with Leucocytozoon simondi . The blackfly ( Simulium innocens ) is considered to be the prime vector in the transmission of this blood parasite to goslings.
Examination of blood films from wood ducks ( Aix sponsa ) from several northeastern states revealed Haemoproteus , Leucocytozoon , Plasmodium and a typanosome. Haemoproteus occurred in all areas sampled and birds of the year from Massachusetts demonstrated the highest incidence during the last 2 weeks in August. Leucocytozoon was most prevalent in more northern areas. P. circumflexum and a trypanosome are reported for the first time from this host.
Serum protein changes were studied in immune and nonimmune pigeons infected with three different strains of Trichomonas gallinae . Strain I (nonvirulent) produced no change in the relative concentration of serum components. Strains II (oral canker) and III (Jones' Barn) produced decreases in albumin and alpha globulins, and increases in beta and gamma globulins between the 7th and 20th days post infection. Birds infected with strain II began to return to normal by the 20th day, while all those infected with strain III were dead between 10 and 14 days post infection. Two serum protein patterns resulted from infection of immune birds with the Jones' Barn strain. One showed no change in relative protein concentrations and no tissue invasion by the parasite while the other was similar to that seen in nonimmune birds infected with a strain producing oral canker. These also showed evidence of tissue invasion by the parasite. It was concluded that tissue invasion was necessary to evoke a quantitative change in serum protein concentrations.
It is postulated that disease is a product of adverse habitats. Overpopulation causes overutilization of food supplies, which results in malnutrition and a decrease in resistance to diseases. Examples of such ecological relationships in populations of Canada geese, California quail, red grouse, deer, rabbits, voles, mice and lemmings are presented.
No abstract available.
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Blood protozoa were first reported from wild birds in 1884. Since then numerous surveys throughout the world have demonstrated their presence in a wide variety of hosts and localities with continuing designations of new species. Taxonomic determinations include parasites in the genera Plasmodium, Haemoproteus, Leucocytozoon, Babesia, Lankesterella and Trypanosoma. Transmission of Plasmodium by mosquitoes was demonstrated with a bird parasite before these insects were proven as vectors of human malaria. All the genera under consideration require an insect vector to complete their life-cycles and susceptible vectors have been demonstrated. Most experimental work on the blood protozoa of birds has been carried on with captive birds. An extensive volume of research has been conducted on Plasmodium because of its close similarity to malaria in man. Field studies that would provide information on the epizootiology of occurrence of these parasites in wild populations have been very limited, mainly confined to single blood film surveys. Such data are inadequate to provide an understanding of true prevalence or incidence or of factual knowledge of their impact on the wild population. Mechanisms for procuring such information are available in some cases and can be developed to fit other situations. Isodiagnosis, inoculation of blood from wild birds into susceptible captive hosts, has revealed a prevalence of over 60 % for Plasmodium in situations where microscope examination of single peripheral blood preparations yielded less than 1 %. Culture of bone marrow collected by biopsy demonstrates high prevalence of trypanosomes even when none are evident from microscopic examination of blood. Often preparations of tissues collected at necropsy reveal Leucocytozoon and Lankesterella when examination of peripheral blood gave no indication of infection. Methods developed by bird ringers provide techniques for obtaining repeat examinations of free-living birds that can yield further pertinent data. The use that has been made of these techniques, beyond the mere procurement of a single blood film, is reviewed from the standpoint of providing knowledge of the epizootiology of the blood protozoa of birds and their further potential is projected.
No abstract available.
One thing seems to stand out in the overall knowledge we have of the blood parasites of waterfowl, as previously noted by Herman and Wehr, (1954): the greatest potential of losses is in the younger age groups, usually those birds 5-10 weeks old. In Leucocytozoon infections, death occurs as early as the first or second week of the bird's life. As a conclusion to this presentation, I wish to emphasize that there are many gaps in our knowledge of these parasites and that the answers are to be obtained by further studies in the young birds. Data obtained from studies of birds shot by hunters or from specimens taken during fall or winter banding operations can be expected to be far less rewarding and significanf than studies of goslings and ducklings. We need much more knowledge of these parasites and their vectors and other relationships before we can develop management procedures to combat or contain them. It will require many more studies in depth to achieve this goal, but the facts are there waiting to be uncovered. These parasites will have to be regulated along with breeding habitat, hunter take, and other factors that all add up to maintenance and management of waterfowl.
The occurrence of Haemoproteus in pigeons throughout the world and in mourning doves in the United States is reviewed. Haemoproteus has previously been reported only once from pigeons in Maryland. During this study it was found in all of 18 pigeons from one area but in none of 12 from an adjacent area. No infections were found in 90 Maryland mourning doves. All of the 10 mourning doves from Florida were infected whereas 60 nestlings from Texas and Mississippi had no parasites. None was found in 358 nestling white-winged doves from Texas.
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Sarcocystis sp. obtained from wild populations of grackles, Quiscalus quiscula (Linn.), were examined to clarify the effect of the parasite on the host. Electron micrographs are presented to show areas of muscle destruction adjacent to the parasite which appear to be mechanically produced by the parasite. The microtubules within the villus-like projections of the cyst suggest that their possible function is absorptive and/or conductive with regard to the production of a toxin or the conveyance of nutritive material to the developing cells. The proposed function of submembranous filaments and their relation to the conoid is discussed. Similarities in the ultrastructure to Toxoplasma and other protozoa tend to negate the relegation of Sarcocystis to the fungi and further emphasize its protozoan nature.
The theme of this book is conservation. Animals are included in this work primarily on the basis of the traumatic injuries they inflict, the venoms they inject, and their poisonous character as food.