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Background: Lernaea cyprinacea was introduced in South America with cyprinids. To the best of our knowledge, this ectoparasite has not been reported in Santa Fe province (Argentina). Objective: To report Lernaea cyprinacea presence in Rhamdia quelen under hatchery conditions in Santa Fe province (Argentina). Methods: In May 2014, samples of L. cyprinacea attached to the fins and flanks of R. quelen were obtained in the Chronobiology Laboratory of the Veterinary Sciences School at Esperanza (Santa Fe, Argentina) where they were collected and identified. Results: A description of L. cyprinacea is presented along with detailed records previously reported in this and other regions. Conclusions: Presence of this parasite constitutes evidence of the introduction of exotic species through commercialization of their natural hosts and the potential pathogen colonization of natural environments, which constitutes a threat to the integrity of aquatic ecosystems., Resumo Antecedentes: Lernaea cyprinacea foi introduzido na América do Sul através de ciprinídeos, não sendo registrado na província de Santa Fe. Objetivo: relatar a sua presença no Rhamdia quelen, em condições de crescimento. Método: em maio de 2014, foram obtidas individuos de L. cyprinacea, parasitando nadadeiras e flancos em R. quelen, no Cronobiologia Laboratório da Faculdade de Ciências Veterinárias, Esperanza (Santa Fe, Argentina), que foram coletados e identificados. Resultados: uma descrição de L. cyprinacea é relatada, e detalhes prévios da presença deste parasito na região. Conclusões: a presença neste parasito é evidência de introdução de espécies exóticas através da comercialização de seus hospedeiros naturais. O potencial de colonização de patógenos introduzidos em ambientes naturais é uma ameaça à integridade dos ecossistemas., Resumen Antecedentes: la Lernaea cyprinacea fue introducida en América del Sur a través de los ciprínidos, no habiendo siendo previamente registrada en la provincia de Santa Fe (Argentina). Objetivo: reportar la presencia de Lernaea cyprinacea en Rhamdia quelen en condiciones de acuicultivo. Método: en mayo de 2014, se obtuvieron ejemplares de L. cyprinacea, parasitando aletas y flancos de R. quelen en el laboratorio de Cronobiología de la Facultad de Ciencias Veterinarias, en Esperanza (Santa Fe, Argentina), donde fueron colectados e identificados. Resultados: se brinda una descripción de L. cyprinacea y se detallan antecedentes del ectoparasito en ésta y otras regiones. Conclusiones: la presencia de este parásito constituye evidencia de introducción de una especie exótica mediante la comercialización de sus hospedadores naturales y de la potencial colonización por patógenos introducidos en ambientes naturales, lo cual amenaza la integridad de estos ecosistemas.

The study of the utilization of sterols by the fungus Lagenidium giganteum has been continued and expanded. The organism uses a wide range of natural sterols and synthetic sterols, which induce zoospore formation. The antibiotics nystatin and amphotericin have been shown to repress zoospore production. The study of sterol utilization and metabolism has been initiated, and work on general fungal physiology has been continued. It has been noted that lipoidal substances seem to be required for utilization of ammonium ion. The fungus protease has also been further isolated and purified and it seems to belong to the serine, alkaline trypsin class. Mosquito proteases have been further analyzed from Culex pipiens and Aedes epactuis. On the basis of further examination and study, it appears that a new trypsin like alkalophilic enzyme is present. A new, more reliable purification procedure has been developed., See also report dated 1 Jul 1975, ADA014171.

Studies were performed to investigate the use of pressure filtration as a means of isolation of free merozoites from an asynchronous sample of infected blood (Plasmodium berghei). Although the procedure does yield large numbers of merozoites which appear intact using morphological criteria, the preparation also was found to contain large numbers of free trophozoites and a small but consistent number of intact parasitized and non-parasitized erythrocytes. If, by the use of multiple filtration steps, all contaminating red cells were removed from the preparations, the numbers of free parasites isolable which could invade normal mouse red cells in vitro was substantially reduced, if not totally abolished. Merozoite invasion in vitro has been found to be highly susceptible to small variations in medium pH, a finding which may be exploited in the future to studies to dissociate schizont rupture/merozoite release from merozoite invasion.

Dirofilaria immitis is found in the heart and subcutaneous tissue of mammals throughout the United States. The life cycle is indirect requiring a mosquito for the infective stage to develop. In humans, the predominate infection is in women over thirty-five years of age having a home in southern states. Although infection rates are small, the medical profession must remain aware of the possibility of the disease.

A comparative investigation of the nature of the trehalase of Culex quinquefasciatus pipiens and the trehalase of its fungal parasite Lagenidium giganteum shows some very important control differences. The mosquito enzyme is under regulatory control; in contrast, the mycotic enzyme is not, and is a more rugged enzyme seemingly constructed for more advantageous utilization of trehalose. The implications in parasitology and biological control are discussed. Further work has been done on the analysis of the amino acids and sugars in Culex as well as Aedes - both normal and infected populations. The fungus has been shown to produce a strong extra-cellular protease whose partial characterization shows that it is an alkaline enzyme, serine catalyzed, approximately 10,000 daltons molecular weight and is probably involved in infection by the zoospore.

The mosquito parasite Lagenidium giganteum was found to possess no detectable sterols, and the organism grew as a saprobe. The fungus took up phytosterols, such as beta-sitosterol, campesterol, ergosterol and desmosterol and these substances were found to be essential for zoospore production and thence conversion of the fungus to a mosquito parasite. Oils that are rich in three phytosterols, beta-sitosterol, campesterol and stigmasterol were found to be very effective zoospore producers. These sterols are found in soy bean oil and in hemp seed oil in these approximate ratios. Sterol preparations from hemp seed were very effective in inducing zoospore production, and this has confirmed the authentic sterols tested. The phytosterols are found in many insects and it was hypothesized that these substances are the keystone to this particular parasitism. This is the first Lagenidium species ever shown to require sterols for zoospore production., See also AD-A013 576.

In the past year a neutralization test was developed capable of detecting antimerozoite antibody in the serum of rats recovering from malaria. It has been demonstrated that such serum also contains opsonic antibody which markedly stimulates phagocytosis of merozoites by phagocytes from normal rats but does not contain antibody that stimulates phagocytosis of erythrocytes from infected rats. Injection of freeze thawed erythrocytic merozoites protects rats from the effects of challenge with parasitized erythrocytes. It is now possible to determine by immunization and neutralization procedures whether specific antigens associated with erythrocytic merozites significantly contribute to stimulation of immunity in malarious rats., Revision of report dated Aug 74, AD-785 724.

Five species of freshwater crabs were collected at four localities in Panama, of which three species were identified as Potamocarcinus richmondi, Ptychophallus montanus cocleensis and Ptychophallus exilepes. The latter two species were new hosts of Paragonimus. Fifty-two or 18% of 293 crabs were infected with 105 Paragonimus metacercariae, which were separated into 13 A-forms, 91 B-forms and one C-form. The A-form was identified as Paragonimus peruvianus Miyazaki et al., 1969, and the B-form as P. caliensis Little, 1968, but the C-form was unknown. P. exilipes harbored mainly B-form, and the other crabs mainly A-form. The metacercaria of P. peruvianus was first found in Costa Rica at two localities mainly from Ptychophallus tristani and rarely from Potamocarcinus magnus., See also annual rept. no. 10, AD-767 753.

The objectives of the investigation were to: (1) characterize the antigenic components and immunologic relationships between trypanosomes of the subgenera Herpetosoma and Schizotrypanum, (2) describe antibody responses to the parasites, (3) determine the effects of homologous and heterologous antisera on the growth of the trypanosomes in vitro and (4) ascertain whether immunization with live parasites, somatic antigens and exoantigens elicits a functional immunity to Trypanosoma cruzi infection.

The natural vertebrate hosts of pathogenic arboviruses that infect man in Ethiopia are identified. The methods of study are (1) collection and identification of vertebrate animals species areas where the viruses are endemic, (2) determination of the immunological status of the material, and (3) elucidation of the relative ecological and epidemiological importance of the infected vertebrates. Five study areas have been established representing a diverse cross-section of habitats and geographic regions., See also report dated 20 Sep 74, AD-787 611.

There is strong experimental evidence that virus infection after exposure to hyperbaric oxygen stress 'favors the virus over the host cell'. Viral mRNA degredation is lessened by diminution of lysosomal RNA-ase leakage. In turn the interferon synthesising capability of the host is markedly reduced by direct action of hyperbaric oxygen or compounds such as adrenochrome which mimic its action under normal pressure., See also report dated 9 Sep 70, AD-711 625

The purpose of this project is to identify the natural vertebrate hosts of pathogenic arboviruses that infect man in Ethiopia. The methods of study are collection and identification of vertebrate animals species areas where the viruses are endemic, determination of the immunological status of the material, and elucidation of the relative ecological and epidemiological importance of the infected vertebrates. Five study areas have been established representing a diverse cross-section of habitats and geographic regions. Sera have been tested against three Group B hemagglutinating antigens. These tests confirm the previous findings that there are no major differences in antibody rates between the five areas. (Modified author abstract), See also report AD-765 335.

The report discusses the effect of mosquito density on feeding behavior of Culex tarsalis was studied. Preliminary data indicate that mosquito density does affect the feeding behavior of C tarsalis. With the other mosquito species collected during the course of this study mosquito density does not appear to affect feeding preference, but receptivity of the host does. Data have been acquired on mosquito blood meals identified by the precipitin test as feeding on lagomorphs and now tested by the passive hemagglutination inhibition test (PHI). A clear pattern of preference for Lepus californicus (jackrabbit) was established for 8 of 9 mosquito species. Further data were secured from mosquitoes collected in Kern County during the 1960-62 study. These blood meals, from passeriform birds, were further identified by the PHI test and about 39% had fed on English sparrows and House finches. (Modified author abstract), See also AD-764 301.

The studies undertaken in the contract are fully counter to the recent and much-quoted contention that ticks and domestic animals play a significant role in the ecology of epidemic typhus and, instead, strongly suggest that the serological data that had been presented in support of such a hypothesis are based upon artifacts. Thus, out of 861 Ethiopian livestock sera and 2,849 sera from Egyptian domestic animals tested by complement fixation (CF) in our program, none of the samples contained antibodies specific for rickettsiae of either epidemic typhus or murine typhus. Moreover, 821 of 822 sera from Egyptian donkeys were anticomplementary and therefore nonspecifically 'positive' in CF tests. It is our opinion that the identical or a similar anticomplementary substance, identified by us as IgM, accounted for the results reported as 'positive' by earlier workers. (Modified author abstract)

The primary aim of the project is to identify the natural vertebrate hosts of arboviruses infecting man in Ethiopia, through the collection and identification of animal species inhabiting areas where the viruses are endemic, and the determination of the immunological status of the material. The relative ecological importance of infected vertebrates is being assessed. Five study areas have been established from which approximately 33,500 animals have been captured. Over 9,000 sera have been tested against three Group B arbovirus hemagglutinating antigens. A detailed analysis of the bird sera shows that there is no major difference in over-all antibody rates between the five areas and that species of birds in eight families provide results which are to be pursued in greater detail; adequate samples are available from six species in eight families which show that they are not reservoir or amplifying hosts of Group B arboviruses. Among other groups there is a high incidence of Group B antibody in a monkey, a baboon, two fruit bats and a lizard. Rodents and amphibia are of little or not importance.

A study of the ecology, distribution, and abundance of mammalian arthropod ectoparasites, arboviruses, and their hosts is being conducted in Venezuela, attempting to recognize and define species, to map their distribution and abundance, to discover and define dominant environmental factors limiting populations, and to analyze parasite-host-habitat relationships. Systematic studies were completed on eight parasite groups., See also report dated 15 Jul 1971, AD728506.

This report deals with material collected or received from 1 September 1969 to the present. Identifications for all specimens are not available at this time. Host collections for the period total 522. These were made from a number of areas in Nepal as well as Darjeeling. Hosts of ectoparasites fall into three categories: birds, humans, and domestic mammals and wild mammals. Accurate identifications for birds and domestic mammals are readily available, as are those for the larger game mammals. Major difficulties have been encountered in obtaining accurate determinations for the smaller mammals, especially insectivores and rodents. Tentative identifications are thus available for most of the host animals. However, particularly difficult groups are presently under study by specialists and positive assignment of names must await their decision., See also Progress rept. no. 4, AD694542.

Studies were designed to investigate the distribution of oncomelanid snails in Taiwan, the susceptibility of oncomelanid snails from various areas to infection with human and zoophilic strains of Schistosoma japonicum, the nature of definitive host for Ilan strain of S. japonicum, and adaptation of S. japonicum in Oncomelania hupensis chiui. In addition, gel-diffusion studies on sera from animals infected with S. japonicum were also made.

Approximately one thosand vials of preserved nematodes, collected from fishes, amphibians, reptiles, birds and mammals were studied by conventional parasitological techniques. Species new to science were described and named. Poorly known species were redescribed, often with revision of the higher categories of classification and with identification keys to the genera and species. New host and distribution records were recorded, and those parasites with obvious potential for infecting man were noted., See also report dated Mar 1970, AD698471.

Two genetic markers of Venezuelan equine encephalomyelitis virus manifested upon multiplication of the virus in Aedes aegypti mosquitoes and directly related to each other are described: qualittative amplification of the virus in mosquitoes and capacity to penetrate into the salivary glands and to be transmitted by bite. These genetic markers are very closely related to genetic markers manifested in virus multiplication in mice: pathogenicity after intracerebral and intraperitoneal inoculation and viremia levels., Trans. of Voprosy Virusologii (USSR) v16 n4 p412-415 1971.

Utilizing the scanning electron microscope (SEM), new dimensions in the study of mammalian parasites and resulting diseases were realized. With the SEM, parasites from laboratory animals were readily identified, and in many instnaces the host-parasite reactions studied. Included in this report are protozoan diseases, and, those caused by an Arthropod and several Helminths., Pub. in Scanning Electron Microscopy, p549-556 1973.

The studies undertaken are fully counter to the recent and much quoted contention that ticks and domestic animals play a significant role in the ecology of epidemic typhus and, instead, strongly suggest that the serological data that had been presented in support of such a hypothesis are based upon artifacts. Thus, out of 861 Ethiopian livestock sera and 2,849 sera from Egyptian domestic animals tested by complement fixation (CF) in the program, none of the samples contained antibodies specific for rickettsiae of either epidemic typhus or murine typhus. Moreover, 821 of 822 sera from Egyptian donkeys were anticomplementary and therefore nonspecifically positive in CF tests. The identical or a similar anticomplementary substance, identified as IgM, accounted for the results reported as 'positive' by earlier workers. These results indicate that such domestic animals could not serve as a reservoir or source of infection of ticks with R. prowazeki in nature. (Modified author abstract), See also report dated 30 Sep 73, AD-783 069.

A series of 25 field stations were established from which 4000 snails were collected. These snail hosts serve as hosts of both of the endemic schistosome species (Schistosoma haematobium from Bulinus truncatus, Bu. abyssinicus, Bu. sericinus, and Bu. forskalii; and S. mansoni from Biomphalaria pfeifferi) and a number of possible trematode antagonists among the echinostome species found parasitizing these snails. About 75 collections of cercariae were made and analyzed. A species of 43-spined Echinoparyphium proved to be a widespread parasite in the various forms of Bulinus collected both in Ethiopia and Egypt. Efforts to develop this species as a biological control of S. haematobium are underway. Factors required for successful biological control are described and discussed.

The work involves the analysis of intact phospholipids in erythrocytes and plasma from rhesus monkeys and in parasites recovered from infected monkeys. The combined thin-layer chromatography-colorimetric assay has a limit of detection of 0.015 micrograms of lipid phosphorus. In comparing erythrocytes from the same animal before and after infection, the greatest difference seen is in phosphatidylinositol. Several differences are apparent between the phospholipids of parasites and infected host cells. Phosphatidylinositol, phosphatidylcholine, and phosphatidylethanolamine represent larger percentages in the parasite than in the host. In particular, the average phosphatidylinositol content is 1.8% in infected host cells and 4.5% in parasites. Sphingomyelin is strikingly different in the two membranes as well. In the parasite it usually represents less than 20% of its level in the infected red blood cells. (Modified author abstract)

A collaborative study with the Gorgas Memorial Laboratory of Panama was completed on the study of the feeding patterns of Culex Melanoconion mosquitoes. This study demonstrated the wide host range of several species of these mosquitoes. Studies were continued in the Northern part of the Sacramento Valley of California to secure base line feeding patterns of several mosquito species found in that area. These data were secured by using the capillary precipitin test and where more definitive data was desired, the newly developed Passive Hemagglutination Inhibition test (PHI) was used. Further data were secured this past year from mosquitoes collected in Kern County during the 1960-62 study. These blood meals, from Passeriform birds, were further identified using the PHI test and about 50 percent were found to have fed on English sparrows and House finches. Six primate antisera were prepared to determine, by the PHI test, the degree of cross-reactivity with serum proteins from several Primate species. The antisera were tested against 17 Primate and one non-Primate species. (Author), See also report dated 1 May 72, AD-744 530.

The purpose of this project is to identify the natural vertebrate hosts of pathogenic arboviruses that infect man in Ethiopia. The methods of study are collection and identification of vertebrate animals species areas where the viruses are endemic, determination of the immunological status of the material, and elucidation of the relative ecological and epidemiological importance of the infected vertebrates. Five study areas have been established representing a diverse cross-section of habitats and geographic regions. (Modified author abstract), See also Annual rept. no. 1, AD-747 309.

Contents: Growth of Swiss Webster male mice fed mouse chow and infected with Trypanosoma duttoni(H strain); Growth of Swiss Webster male mice fed pryidoxine deficient diet and infected with T. duttoni; The development of T. duttoni in mice fed laboratory mouse chow and associated with testosterone propionate treatment; The role of replacement testosterone in castrated mice infected with T. duttoni.

The basic technique which makes controlled experiments with infective microfilariae (Dirofilaria immitis) possible is the experimental production of third-stage filariae. The technique described is one which has been used by the 406th Medical Laboratory for many years; its development has been the work of many investigators from the Department of Entomology and the Department of Veterinary Medicine. (Author)

The report discusses the immature stages of Ixodid ticks of Central Africa. Ticks as disease vectors and host parasite relations are emphasized.

The size and shape of the female head and mouth-parts of Chrysops vittatus Wiedemann, Hybomitra lasiophthalma Macquart and Tabanus lineola Fabricius are illustrated and compared quantitatively. The functions of the mouthparts are discussed. It is suggested that the short, broad proboscis of tabanines, in contract to that of chrysopines, may restrict them to feeding on vertebrates with short or sparse hair and on flowers with shallow nectaries. (Author)

Significant progress has been made in finding a testing method that can be used for the definitive identification of arthropod blood meals. This method, a passive hemagglutination inhibition (PHI) technique, now has been placed into routine use in the laboratory to test mosquito blood meals. Over 1400 such tests have been made with the PHI technique and the data are recorded in this report. Additional modifications of the basic technique have been made in an effort to conserve valuable reagents and time. Continued testing of mosquito blood meals have been made using the basic capillary precipitin method. These mosquitoes were collected in Panama and the Sacramento Valley of California. (Author)

A total of 4887 collections of ectoparasites were made in Nepal during the four year collecting period. Since much of the material remains to be studied by the various specialists associated with the project, only rough estimates of the number of taxa involved can be made at this time. A resume by group of the various ectoparasites is presented. Complete host identifications are still not available for some groups. All of the avian hosts have been determined. Identifications are also available for the large mammals. There are still many systematic problems to be dealt with among the insectivore, chiropteran and roden hosts, however, and specialists are working over these groups at present., Prepared in cooperation with American Univ., Beirut (Lebannon), Contract N62558-5023. See also Semiannual progress rept. no. 6, AD-720 760.

In Japan, Angustassiminea nitida var. was found to be a new snail host for P. iloktsuenensis on Amami-Oshima Is. and for P ohirai on Tanegashimo Is. of Kagoshima Prefecture. By using a scanning electron microscope, the body surface of cercariae of P. miyazakii and P. iloktsuenensis as well as eggshells of P. kellicotti, P. mexicanus and P. peruvianus were clearly demonstrated. Outside Japan, P. macrorchis and P. siamensis were recognized in Ceylon, and Parathelphusa rugosa and ceylonensis were decided as the crab host for the former and the latter fluke, respectively. P. siamensis was recognized also in India. In Laos, adults of P. heterotremus were removed from the human lungs, showing medical importance of this fluke in Laos and in Thailand. In Korea, two forms of Paragonimus were noted from Eriocheir japonicus on Cheju Is. In Peru, the metacercaria of P. peruvianus was clarified for the first time, and it was concluded that the human disease in Cajamarca Province is not caused by P. westermani, but by the indigenous lung fluke, P. Peruvianus. (Author)

Since the study of a few bacteriophage systems has significantly contributed to an understanding of virus-host relationships, the study of additional systems, differing from those already in existence, might be expected to add to the knowledge in this area. Since the Salmonella group of organisms constitute a group of significance to man being responsible for such diseases as the typhoid and paratyphoid fevers, enteric fever and Salmonellosis, and since a diversity of types of Salmonella phages has been described and since many new methods of investigation now exist not available to earlier workers, it seemed desirable to examine the systematics of the Salmonella phages. A group of phages isolated from lysogenic strains of S. potsdam was selected for study. As a result of the investigations, the Salmonella phage groupings originally suggested by Burnet have been revised. One of the newly defined groups, called group B, includes phages of a new morphology not previously described. Group B phages were found also to have a host range that included E. coli.

The relationship between the malaria parasite and the host erythrocyte, and the fine structure of the malaria parasite and the host erythrocyte were studied by various microscopic techniques. The techniques used included freeze etching, carbon replication, scanning electron-microscopy and phase and Nomarski microscopy. On the basis of these studies it was concluded that penetration by a merozoite produces little effect on erythrocytes of chickens, mice or rats. The erythrocytes, however, become progressively more distorted and their membranes become rougher and more irregular as the parasites increase in size. When parasitemias are still low, and before anemia becomes severe, nonparasitized erythrocytes in the infected animals circulation may show little change from normal. When parasitemias are high and anemia is severe and particularly when many basophilic erythrocytes are present in the circulation, many nonparasitized erythrocytes are irregularly shaped and have rough distorted membranes. Some of the membrane characteristics and shape irregularities seen in these later stages of the patent parasitamia, and also still later during recovery, are similar to those seen in animals compensating for blood loss following bleeding. (Author)

By means of serum neutralization tests, additional vertebrate hosts of the WE virus have been identified in Saskatchewan and the Northwest Territories. Infection rates indicate that pigs might be more sensitive indicators of virus activity in nature than domestic poultry. The known northern distribution of Culex tarsalis is reviewed. C. tarsalis is the principal epidemic transmitter of WE in Western Canada. Although this mosquito has been recorded as far north as Norman Wells, N.W.T., it is not abundant north of the prairie farmlands. It is concluded that transmission of the virus to wildlife in these northern areas must be accomplished by Culiseta inornata or the hordes of pest Aedes mosquitoes. (Author)

Seven species of Saskatchewan mosquitoes were found infected with the virus of western encephalitis (WE) in nature. The majority of WE virus isolations from mosquitoes were made during July and August, the months when epidemics begin. In 2 epidemic years the majority of the isolations from mosquitoes were from Culex tarsalis which had higher seasonal infection rates and generally larger infected populations than any other species in 5 collecting areas. In 1 interepidemic year, isolations of WE virus from species of mosquitoes other than C. tarsalis predominated and in at least 1 locality 1 of these species had a high seasonal infection rate and a relatively large infected population. Based on ecological and epidemiological evidence, it is concluded that, in Saskatchewan, C. tarsalis is the principal epidemic transmitter of the WE virus and that other species maintain the enzootic status of the disease. On similar grounds, Culiseta inornata may be a significant transmitter of the virus in epidemics of WE in horses in Saskatchewan. Infected mosquitoes have been found in most of the agricultural area of the province except the Southwest, but testing of larger numbers of specimens from the Southwest would probably reveal infected mosquitoes in that area. (Author)

A total of 4042 host and ectoparasite collections were made. The status of identifications varies with the various groups of ectoparasites. Determinations are complete for the fleas and ticks. The bulk of the mite collections remains to be studied. Determinations for all avian and domestic animal hosts are complete. Wild mammal hosts are now under study. It is hoped that additional host and parasite collections can be made in the mountains of Mustang District during April and May of this year., See also Progress rept. no. 5, AD-701 348.