Gorgas Memorial Laboratory Research Articles

The human malaria-Aotus monkey model: a historical perspective in antimalarial chemotherapy research at the Gorgas Memorial Laboratory-Panama.

The human malaria-Aotus monkey model has served the malaria research community since its inception in 1966 at the Gorgas Memorial Laboratory (GML) in Panama. Spanning over five decades, this model has been instrumental in evaluating the in vivo efficacy and pharmacokinetics of a wide array of candidate antimalarial drugs, whether used singly or in combination. The animal model could be infected with drug-resistant and susceptible Plasmodium falciparum and Plasmodium vivax strains that follow a characteristic and reproducible course of infection, remarkably like human untreated and treated infections. Over the years, the model has enabled the evaluation of several synthetic and semisynthetic endoperoxides, for instance, artelinic acid, artesunate, artemether, arteether, and artemisone. These compounds have been evaluated alone and in combination with long-acting partner drugs, commonly referred to as artemisinin-based combination therapies, which are recommended as first-line treatment against uncomplicated malaria. Further, the model has also supported the evaluation of the primaquine analog tafenoquine against blood stages of P. vivax, contributing to its progression to clinical trials and eventual approval. Besides, the P. falciparum/Aotus model at GML has also played a pivotal role in exploring the biology, immunology, and pathogenesis of malaria and in the characterization of drug-resistant P. falciparum and P. vivax strains. This minireview offers a historical overview of the most significant contributions made by the Panamanian owl monkey (Aotus lemurinus lemurinus) to malaria chemotherapy research.

Short report epidemiologic studies on cutaneous leishmaniasis in eastern Panama.

The Panamanian Ministry of Health, through the Interamerican Development Bank, contracted the Gorgas Memorial Laboratory to conduct epidemiologic studies on leishmaniasis and malaria in eastern Panama from July 1984 through June 1985. Preliminary results of the biomedical and entomologic teams investigating the epidemiology of cutaneous leishmaniasis in the eastern part of the country are presented in this short report. The principal findings of the study revealed 1) a large disparity in the incidence and prevalence of the disease among the five communities investigated; 2) the appearance of self-cures without the benefit of effective treatment; 3) a relatively high percentage of subclinical cases; and 4) determination of the sandfly vector species for each community. Also reported here is a case of a double infection with two distinct species of Leishmania, L. mexicana and L. amazonensis, in a single individual.

Contributions to Avian Biogeography From the Archipelago and Lowlands of Bocas Del Toro, Panama

-New distributional information is summarized from avifaunal surveys conducted from 1987 to 1991 in the ornithologically unknown islands of the province of Bocas del Toro, Panama, and points on the adjacent mainland. These establish the region of the Laguna de Chiriqui to be of great biogeographic interest and complexity. New records include 3 species new to Panama, and 11 species and 3 subspecies new to Bocas del Toro. Two taxa of birds (Platyrinchus cancrominus and a form of Chlorophanes spiza) are relicts on islands and are not resident on the Panamanian mainland. Four pairs of species or subspecies (Anthracothorax prevostiilA. veraguensis, Glaucis aenea/G. hirsuta, Gymnopithys bicolor olivascensIG. b. bicolor, and Tangara inornata rava /T. i. languens) are shown for the first time to change abruptly over a narrow distance along the southern shore of the Laguna de Chiriqui. Received 6 January 1992, accepted 22 April 1992. THE PROVINCE of Bocas del Toro occupies the western quarter of the Caribbean coast of Panama. Its most distinctive physiographic feature is a large embayment (Laguna de Chiriqui/Bahia de Almirante) encompassing many islands, some quite large (Fig. 1). Along the southern shore of this embayment, lowland habitats are very restricted because of the proximity of mountains to the sea. Other factors that may have biogeographic significance are the presence of a deep channel (20 to 30 fathoms) between the Valiente Peninsula and Cayo Agua, and an extensive area of swamp at the southeastern corner of the Laguna de Chiriqui. Systematic ornithological collecting in Bocas del Toro began in 1926 (Kennard and Peters 1928) and continued actively for a few years, but then fell off for a quarter century (Eisenmann 1957). Alexander Wetmore made substantial collections for the Smithsonian Institution in 1958, but with minor exceptions almost exclusively near Almirante. In the 1960s, the Gorgas Memorial Laboratory operated hundreds of mist nets near Almirante in connection with epidemiological research, which added considerably to ornithological knowledge of the

Human T-Lymphotropic Virus Type II Among Guaymi Indians—Panama

Human T-lymphotropic virus type 2 (HTLV-II) is one of four retroviruses (i.e., HTLV-I, human immunodeficiency virus type 1 [HIV-1], and HIV-2) that are known to infect humans. During 1988, investigators from the Gorgas Memorial Laboratory (GML) and the National Institutes of Health (NIH) tested serum specimens collected during 1978-1987 throughout Panama to determine the prevalence of HTLV-I infection (1), which is endemic in southern Japan and the Caribbean basin (2). HTLV seropositivity rates were low in all areas of Panama except among the Guaymi Indians in Changuinola (9%),* a city in western Panama (Figure 1). During 1989-1991, additional testing of 36 seropositive specimens from Guaymi Indians detected that the infections were due to HTLV-II (3,4). This report summarizes risk factor data for HTLV-II infection among Guaymi Indians.

The Digenetic Trematode Collyriclum faba (Bremser in Schmalz, 1831) in Migrant and Local Birds from Panama

A bird migration study was conducted by Florida State University during portions of the years 1967 and 1968 in the western part of the Republic of Panama. A total of 3,896 wild birds were banded between September and October 1967 at the Gorgas Memorial Laboratory's field station at Almirante (A), Bocas del Toro province, situated at sea level near the Caribbean coast in a tropical rain forest. Another 874 birds were banded from September to December 1967 and in March of 1968 at the Florida Audubon Society's field station at Cerro Punta (CP) situated at an altitude of 5,500 ft in the tropical cloud forest of Chiriqui province. Small nodular lesions resembling the tumours of avian pox virus, studied at the same locations (Kirmse and Loftin, 1969, Bulletin of the Wildlife Disease Association 5: 103-107), were found xclusively on the base of the lower mandible, the chin, or throat of the birds. They appeared as single subcutaneous cysts ranging in size from a pinhead to a cherry. They were easily removed through a small incision in the skin. Healing was promoted after application of tetracycline powder and birds from which lesions had surgically been removed showed no further sign of infestation when retrapped. On dissection the cysts contained a viscous yellowish-brown liquid in wh ch oval-shaped yellowish mature flukes were detecte , in numbers ranging from 1 to 8 specimens (mean 3.3) and measuring in diameter from 0.5 to 2.0 mm.

Acute hemorrhagic conjunctivitis epidemic in Colon, Republic of Panama.

Acute hemorrhagic conjunctivitis has caused numerous outbreaks throughout Africa and Asia since it was first recognized in 1969 but did not involve the New World until 1981. This unprecedented outbreak reached Colon, Panama during August 1981 and by October 8,401 cases had been reported (14% of Colon's population). In October the Gorgas Memorial Laboratory and Ministry of Health conducted a survey in Colon to collect descriptive data on household living units, epidemiologic and clinical data from residents, and venous blood from all residents one year or older. The survey sampled 127 households and interviewed 608 people (1% of Colon's homes and 1% of the population). Overall 336 (55%) study subjects recalled having conjunctivitis. Disease rates differed according to residence; poor sectors of the city had 67% attack rates, lower class 52%, middle class 34%, and upper class 13%. Within each sector adults were more likely than children to be index cases, and communal bathrooms and household crowding were the most important risk factors for acute hemorrhagic conjunctivitis. Between 4-20% of people denying acute conjunctivitis had antibody to enterovirus 70 and may represent asymptomatic cases.

Cancer as a World Problem

Research Article| March 01 1985 Cancer as a World Problem Maura C. Flannery Maura C. Flannery Search for other works by this author on: This Site PubMed Google Scholar The American Biology Teacher (1985) 47 (3): 173–175. https://doi.org/10.2307/4448000 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation Maura C. Flannery; Cancer as a World Problem. The American Biology Teacher 1 March 1985; 47 (3): 173–175. doi: https://doi.org/10.2307/4448000 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentThe American Biology Teacher Search This content is only available via PDF. Copyright 1984 The National Association of Biology Teachers Article PDF first page preview Close Modal You do not currently have access to this content.

The ecology of cutaneous leishmaniasis in the Republic of Panama.

Ecological studies on leishmaniasis at Gorgas Memorial Laboratory, Panama, over the past 4 decades are reviewed and supplemented with unpublished data relating to sand fly vectors, sylvatic reservoir hosts, parasites, and the clinical disease. The systematics, microhabitats, breeding sites, seasonality, flight activity, rearing, predators, host-feeding profiles, and vector competence of the Panamanian sand fly fauna are discussed. The reservoir hosts of the 3 indigenous species of Leishmania, Le. braziliensis panamensis, Le. mexicana aristedesi , and Le. hertigi hertigi , are detailed, as well as the disease manifestations within these hosts and experimental animals. Characterization of the indigenous Leishmania subspecies by isozyme electrophoretic patterns is described and compared with that of related taxa within their respective complexes. The prevalence, clinical findings, and characterization of various forms of human cutaneous leishmaniasis in Panama, as well as diagnostic methods and treatment regimens, are outlined.

The identity of the sand fly that first experimentally transmitted a neotropical Leishmania

READY & LAINSON (1982) referred to speculation over the identity of the sand fly which first experimentally transmitted a neotropical Leishmaniu by bite (STRANGWAYS-DIXON & LAINSON, 1962; 1966). Previously published comments on this fly’s identity (WILLIAMS, 1970; WILLIAMS & COELHO, 1978) were based on examinations of the actual specimen and after comparing it with other species of the same subgenus. The Department of Entomology, British Museum (Natural History), which received the specimen in December 1967, recently loaned me the material. In addition to studies on the fly made at the Gorgas Memorial Laboratory, Panama, and at BM(NH), it has now been possible to compare the fly with specimens in the Belo Horizonte reference collection of Phlebotominae. For simnlicitv’s sake. the fly in question is, herein, called “the Belize specimen”. It is impossible to identify the Belize specimen to specific level because it lacks spermathecae, spermathecal ducts and the genital fork. However, from the appearance of certain non-sexual features, the Belize specimen cannot belong to two species of the same subgenus Psychodopygus collected in Belize between 1963 and 1969 (WILLIAMS, 1970), and some species mentioned by READY & LAINSON (1982) can be eliminated. Thoracic pigmentation: The mesoscutum, mesoscutellum and postnotum of the Belize specimen are moderately but distinctly infuscated, and clearly contrast with the paleness of the thoracic pleura. It is unlikely that this colour contrast is an artefact due to distortion of the thorax. The pigment contrast on the thorax of the Belize specimen is similar to that of Lutzomyia (Psychodop$us) panamensis, L. (Ps.) geniculata (= L. (Ps.) guyanensis of some authors) and L. (Ps.) bispinosa, the three species of the subgenus collected in Belize in 1963-69. The Belize specimen, with a pale pronotum, differs from L. (Ps.) bispinosa, in which the uronotum is weaklv infuscate. The orocoxae of the Belize suecimen are as nale as the thoracic pleura. For this reason, the specimen cannot be identified as L. (Ps.) hirsuta nicaramrensis which has darkened procoxae in both sexes(FAIRCHILD & HERTIG, 1961.; YOUNG, 1979). Because of the contrast in thoracic pigmentation, the Belize specimen most certainly cannot be identified as L. (Ps.) carreirai thuZa (= Ps. -pessoanus of READY & LAINSON, 1982). In snecimens of L. (Ps.) carreirai thula. material from Panama and Colombia having been’examined, the entire thorax is pale, or almost so, and there is no noticeable difference in thoracic pigmentation. On the basis of thoracic pigmentation, it can be deduced that the Belize specimen cannot be L. (Ps.) carreirai thula, L. (Ps.) hirsuta nicaraguensis or L (Ps.) bispinosa. Cibarium: The cibarial arch in the Belize specimen and L. (Ps.) pana memis is well defined and complete. In L. (Ps.) geniculata and L. (Ps.) bispinosa, the cibarial arch is not well defined but appears to be complete. The cibarial arch of L. (Ps.) carreirai thula is so weakly defined that it is best described as incomplete. The cibarial pigment patch in the Belize snecimen. L. (Ps.) panamensis and L. (Ps.) geniculata is fairlv ‘well‘ defined and annears as a’ “m it seems to be triangular in shape. The salivary pump in the Belize specimen, L. (Ps.) panamensis and L. (Ps.) bispinosa is roughly circular in optical section and smaller than the pump in L. (Ps.) geniculata and L. (Ps.) carreirai thula, both having an oval-shaped pump along a distal-proximal axis. From the general appearance of the cibarium, it can be concluded that the Belize specimen cannot be identified as L. (Ps.) carreirai thula. L. (Ps.) eeniculata or L. (Ps.) bispinosa. I ~ , ”

40 Years of Tropical Medicine Research. A History of the Gorgas Memorial Institute of Tropical and Preventive Medicine, Inc., and the Gorgas Memorial Laboratory

"40 Years of Tropical Medicine Research. A History of the Gorgas Memorial Institute of Tropical and Preventive Medicine, Inc., and the Gorgas Memorial Laboratory" published on Sep 1974 by The American Society of Tropical Medicine and Hygiene.

Transmission of Three Strains of Plasmodium falciparum from Monkey to Man

Infections of 3 different strains of Plasmodium falciparum in the Aotus trivirgatus monkey were shown to be infectious to 6 different species of Anopheles. The A. freeborni were more readily infected. Transmission of the infection to 20 men was obtained by the bites of infected A. freeborni mosquitoes after extrinsic incubation periods of 13 to 26 days. The prepatent periods in the men ranged from 9 to 13 days with a mean of 11.2 days. It has been reported previously that human malaria in the Aotus trivirgatus monkey is infectious to mosquitoes and that the infections can be subsequently transmitted back to man. Five different strains of Plasmodium vivax, all from Central America, have been transmitted from these monkeys to man via the bites of infected Anopheles albimanus and A. freeborni mosquitoes (Young et al., 1966; Collins et al., 1972). Previously, we had reported the successful transmission of the Malayan IV strain of P. falciparum to two human volunteers (Contacos and Collins, 1968; Collins et al., 1968). Reported here are the results of additional studies on the transmission of three strains of P. falciparum from Aotus monkey to man. MATERIALS AND METHODS The 3 strains of P. falciparum used were (1) the Malayan IV which was isolated from a Peace Corps volunteer who contracted the infection while working in the Central Perak area of Peninsula Malaysia (Chin et al., 1966), (2) the Cambodian I which was isolated from an American parasitologist who contracted the infection while working in the Paillin District of Western Cambodia (Eyles et al., 1963), and (3) the Panama II which was isolated from an 11-year-old Panamanian national residing on the Atlantic side of the Republic of Panama (Collins et al., 1973). The Malayan IV and the Panama II strains have been shown to have some degree of resistance to Received for publication 14 May 1973. * National Institutes of Health, LPD, Building 5, Room 114, Bethesda, Maryland 20014. t Center for Disease Control, Malaria Program, 1600 Clifton Road, Atlanta, Georgia 30333. Mayo Clinic, 4023-18th Avenue, N.W., Rochester, Minnesota 55901. chloroquine. The Cambodian I strain is sensitive to this drug. Aotus trivirgatus monkeys, obtained commercially, had their origin in Colombia, South America. Prior serologic and parasitologic examination indicated that the animals were free of natural malarial infection. The A. freeborni mosquitoes were the F-l strain originally isolated from Marysville, California (Hardman, 1947) and maintained in our laboratory since 1944. The A. maculatus were obtained from the Institute for Medical Research, Kuala Lumpur, Malaysia (Ow Yang et al., 1963) in 1964 and maintained in our laboratory since then. The A. quadrimaculatus were the Q-1 strain which was obtained from Technical Development Laboratories, CDC, Savannah, Georgia, and maintained in our laboratory since 1959. The A. stephensi were from Delhi, India, and were obtained from the London School of Hygiene and Tropical Medicine, London, England, in 1963. The A. balabacensis balabacensis were originally from Thailand and obtained from the Walter Reed Army Institute of Research, Washington, D. C. (Esah and Scanlon, 1966). Three strains of A. albimanus were examined. Two, the Apastepeque and the Melara strains, were established in El Salvador by the Central America Malaria Research Station, CDC, San Salvador, El Salvador; we obtained the colonies from them in 1971. The other strain of A. albimanus was the A-1 strain from Panama which was obtained from the Gorgas Memorial Laboratory in 1972. This study was performed in prisoner volunteers at the Atlanta Federal Penitentiary as part of a research program on evaluation of antimalarial drugs. The technique used for the feedings on the monkeys and on the human volunteers are those previously reported (Collins et al., 1968).

Tropical Medicine

Forty Years of Tropical Medicine Research: a History of the Gorgas Memorial Institute of Tropical and Preventive Medicine, Inc, and the Gorgas Memorial Laboratory. By Willard H. Wright. Pp. xii + 426. (W. H. Wright: Washington, 1970.)

Colonization of Lutzomyia trinidadensis and L. vespertilionis (Diptera: Psychodidae)1

The laboratory colonization of 2 species of New World phlebotomine sand flies, Lutzomyia trinidadensis (Newstead) and L. vespertilionis (Fairchild & Hertig) was accomplished through modifications of standard rearing techniques used at Gorgas Memorial Laboratory, Panama. The development of a new adult sand fly feeding and maintenance cage contributed to consistent hostfeedings by females facilitating subsequent colonization. The colony of L. trinidadensis was terminated after 6 generations. The colony of L. vespertilionis , presently in its 6th generation, is being maintained.

Book Announcement: 40 Years of Tropical Research, a History of the Gorgas Memorial Institute of Tropical and Preventive Medicine, Inc. and the Gorgas Meorial Laboratory

Those who are interested in the history of medical entomology or in the contributions of the Gorgas Memorial Laboratory to medical entomology and parasitology will particularly welcome this volume. The first 6 chapters deal with successive stages in the development of the institution, and the seventh and last chapter reviews projects and contributions from 1929 to 1968. There are a number of appendices giving addresses on significant occasions in the history of the laboratory, lists of staff members and major contributions, and a bibliography of publications through 1969.

40 Years of Tropical Medicine Research. A History of the Gorgas Memorial Institute of Tropical and Preventive Medicine, Inc., and the Gorgas Memorial Laboratory.

40 Years of Tropical Medicine Research. A History of the Gorgas Memorial Institute of Tropical and Preventive Medicine, Inc., and the Gorgas Memorial Laboratory.

Leishmania hertigi sp. n., from the Tropical Porcupine, Coendou rothschildi Thomas

A skin-inhabiting species of Leishmania found in Panama in the tropical porcupine, Coendou rothschildi, is considered new and described as Leishmania hertigi sp. n. L. hertigi is differentiated from other species of Leishmania found in mammals mainly by the nature and course of the infection in its natural host. It is apparently harmless to its host, in which it produces a long-lasting infection, showing a well-established host-parasite relationship. There is a complete absence of any gross skin alteration due to the infection, although the parasite frequently is found in skin over the whole body. L. hertigi seems to be host-specific. In the search for reservoir hosts of human cutaneous leishmaniasis in Panama a new approach was initiated at the Gorgas Memorial Laboratory in March 1965. Starting from the hypothesis that natural leishmanial infections among animals might occur with no gross skin alterations, wild-caught mammals were investigated using skin smears and the recently described biopsy-skin-culture technique (Herrer et al., 1966). The latter technique greatly simplified the detection of parasites in the skin and proved to be very useful in these studies. Early in the investigation, a tropical porcupine, Coendou rothschildi Thomas, was found lightly infected. Subsequent studies showed a high prevalence rate. Morphological and other studies indicate that this is a new species which is described in this paper and named Leishmania hertigi. MATERIALS AND METHODS Porcupines (C. rothschildi) were obtained alive from different localities throughout the central part of the Republic of Panama. Skin from several parts of the body was cultured by the biopsy-skin-culture technique. Skin cultures were made periodically from porcupines maintained in captivity to study the course of the infection. Cultures were also made from skin, liver, and spleen at autopsy. Skin smears were prepared only in certain cases, and skin samples were preserved for sections from animals with positive skin smears. Senekjie's culture medium was used throughout this study, and all cultures were incubated at 19 to 22 C. The parasite could be maintained for about Received for publication 8 September 1970. * The work reported here was supported in part by the research grant AI-01251 from the NIAID, NIH, USPHS. a month before transfer to a new culture. Promastigote (leptomonad) flagellates used for the morphological description were from 2 strains maintained for several months after isolation and were taken from the culture slant 6 to 8 days after a transfer. Drawings were made with the aid of a camera lucida and 80 flagellates were measured for the description. Leishmania hertigi sp. n. (Figs. 1-18) Morphological description (all measurements in microns)

Natural Infections and Behavior of Trypanosoma rangeli and Trypanosoma cruzi in the Vector Rhodnius prolixus in Colombia

r: Hemolymph, salivary glands, and feces of wild-caught Rhodnius prolixus were examined periodically for trypanosome infections. Dissection of a random sample of bugs revealed spontaneous loss of Trypanosoma rangeli in 18% and of T. cruzi in 12% of infections during a mean observation period of 3 months. In T. rangeli-infected bugs repeated examinations increased the observed hemolymph infection rates from around 7% to 26%, and in the whole lot of investigated bugs from 1% to 4%. The presence of T. cruzi in the intestine did not exclude T. rangeli or prevent its invasion of the hemolymph and salivary glands. In half of the T. rangeli and over 10% of T. cruzi infections the flagellates were undetected in feces. In 97% of T. cruzi and 52% of T. rangeli infections the flagellates were in the rectum, and in 53% of T. cruzi and 83% of T. rangeli infections they were in the slender midgut. In two T. rangeli infections flagellates were found in the hemolymph only; all bugs with flagellates in the hemolymph transmitted infection when fed on mice. It is suggested that examination of all organs from a random sample of a large collection of bugs will provide more reliable information than will examination of feces only from the whole lot. Bugs with T. rangeli or T. cruzi infection took a blood meal significantly less frequently than did those without infection. Prevalence ratios of Trypanosoma cruzi and T. rangeli in triatomid bugs reported from various countries of America were summarized by Dias in 1956. These records usually were based on one examination of feces from each bug. The natural occurrence of T. rangeli in hemolymph and salivary glands has apparently been reported only by Pifano and Mayer (1949) in Rhodnius prolixus in Venezuela, by Groot (1952) in R. prolixus in Colombia, and by the Gorgas Memorial Laboratory (1966) in R. pallescens in Panama. Epidemiological interpretation of such data requires more detailed information on the detection and behavior of the trypanosomes in the vector bugs. Reported here are the results of serial examinations of bugs collected in Colombia. Described also are survey procedures which reflect more adequately the extent and significance of natural infections of T. rangeli and T. cruzi in the vector. Preliminary observations on the distribution of R. prolixus in Colombia, Received for publication 20 March 1969. * Supported by the Tulane University International Center for Medical Research and Training, Grant TW-00143 from the National Institute of Allergy and Infectious Diseases, NIH, U. S. Public Health Service. t Present address: Division of Research in Epidemiology and Communications Science, WHO, Geneva. the rates of natural trypanosome infection in the vectors, and the behavior of 10 isolated strains of T. rangeli were reported earlier (D'Alessandro, 1963). MATERIALS AND METHODS Triatomid bugs were collected in houses during June and July of 1962 in 4 states of Colombia (Magdalena, Santander, Cundinamarca, Tolima). R. prolixus was the only species found. On arrival in the laboratory, the bugs were placed in individual containers and the hemolymph of each 4thand 5th-instar nymph and adult was examined. The bugs were then allowed to feed on uninfected mice, a separate mouse being used for each bug in which parasites in the hemolymph were either undetermined or present, or the same mouse for several negative bugs. A sample of naturally voided feces from each bug was examined for flagellates. Thereafter, the bugs with flagellate-positive feces were given an opportunity to feed on a mouse every 8 to 10 days, or after a molt. The hemolymph of 4thand 5th-instar nymphs and adults was always examined after molting, before each blood meal, and 4 to 5 days later. When flagellates were found in the hemolymph, an attempt was made to detect them also in the salivary glands, either by transmission of the infection to mice or by dissection of the glands. Only bugs with flagellates in the feces after the first meal were fed again, and the feces, hemolymph, and salivary glands were subsequently examined. Because of the large number to be studied at the same time the bugs that had no flagellates in the feces after the first meal were not fed again, although the hemolymph was examined

Hepatozoon fusifex sp. n., a Hemogregarine from Boa constrictor Producing Marked Morphological Changes in Infected Erythrocytes

In a large proportion of Boa constrictor taken in the vicinity of Colima, Mexico, hemogregarines were visible in erythrocytes of the peripheral circulation. One characteristic of a majority of these infections was the marked fusiform or spindle shape of many infected red blood cells. Such cells closely resembled certain avian blood cells parasitized by Leucocytozoon. Developmental stages in the blood, and schizogony in the tissues are described. Schizogony occurs primarily in the endothelial cells of lung capillaries but may occur in this type of cell in other organs. The spindle shape of the infected erythrocytes is so distinctive that the organisms are placed in a new species, Hepatozoon fusifex. Culex tarsalis or Aedes togoi, biting B. constrictor with certain types of hemogregarines in their blood developed mature sporozoites in their hemocoels. Similar stages were found in a tick, Amblyomma dissimile, removed from a boa. The hemogregarines were transmitted to clean B. constrictor by feeding them infective C. tarsalis or A. dissimile. It has not been established with certainty whether these sporogonic stages are part of the life history of H. fusifex or belong to a separate hemogregarine species. Hemogregarine parasites frequently produce considerable hypertrophy of the infected blood cells. Marked changes in the morphology of the host cells apart from those associated with hypertrophy are less common. Wenyon (1908) reported that in Haemogregarina gracilis from Mabuya quinquetaeniata, the parasite had the property of pushing out the infected host cell at either end and thus elongating it considerably. In the same paper, Wenyon noted that another sporozoan blood parasite of African snakes, Haemocystidium najae, from Naja haje and from Naja nigricollis, altered the shape of the infected erythrocyte so that the latter came to resemble the fusiform shape of a red cell of the guinea fowl infected by Leucocytozoon. Laveran and Salimbeni (1909) pictured hypertrophied erythrocytes of a Brazilian lizard, Tupinambis teguixin, infected with Haemogregarina tupinambis. Some of these red cells reached a length of 35 yt and became spindleshaped. Other investigators have reported Leucocytozoon-like parasites in the blood of reptiles. However, this designation has been based Received for publication 7 March 1969. * Aided by Grants GB 414 and 7069 from the NSF, Training Grant E-70, U. S. Public Health Service, Grant Zoology 254, University of California, and Sigma Xi-RESA Grant in Aid of Research, 1963. t Present address: Gorgas Memorial Laboratory, P. 0. Box 2016, Balboa Heights, Canal Zone. either on the shape of the parasite or on its presence in leukocytes (Leger and Mouzels, 1917) and in no case did the infected blood cell show a spindle or fusiform shape. Yonge (1966) found round Leucocytozoon-like gametocytes in differentiating blood cells of Natrix sipedon sipedon infected with Cytotoddia. Arcay de Peraza (1968) erected a new genus and species, Paraleucocytozoon lainsoni, for a leukocyte-inhibiting sporozoan of Iguana iguana iguana; and Lainson and Shaw (1969) reported a leucocytozoid with round to oval gametocytes in blood cells of the Brazilian lizard Tupinambis nigropunctatus. The parasite described in the present communication produced much greater elongation of the infected host erythrocyte than was observed by previous investigators, and much more modification in the shape of the parasitized cell than has been noted for other hemogregarine infections. MATERIALS AND METHODS Fifty-five of 57 adult or subadult boas (Boa constrictor)* taken from 1963 through the spring * The host has been placed in either the genus Constrictor or Boa in recent herpetological papers. Our previous report used the designation C. constrictor (Ball, Chao, and Telford, 1967). The use of the generic name Boa instead of Constrictor now seems to be accepted by most herpetologists (Underwood, 1967) and therefore we are using this designation in the present paper.

Epidemiologic studies of Venezuelan equine encephalitis virus in Almirante, Panama.

Grayson, M. A. and P. Galindo (Gorgas Memorial Laboratory, Panama, Re-public of Panama). Epidemiologic studies of Venezuelan equine encephalitis virus in Almirante, Panama.Amer. J. Epid., 1968, 88: 80–96. —Forty-three isolations of Venezuelan equine encephalitis (VEE) virus were made from specimens collected or exposed in a tropical rainforest area of Panama during 1961 and 1962. Six isolates were recovered from febrile patients, seven from field rodents and nine from at least six species of wild birds. Twelve strains of VEE virus were obtained from at least four species of mosquitoes, and nine litters of sentinel mice exposed to the bites of bloodsucking insects also yielded the virus. Serologic evidence of VEE virus activity in the area before 1961 was acquired. Antibodies to VEE virus were detected in 25 species of vertebrates including humans, equines, bovines, canines and domestic fowl as well as several species of wild mammals, birds and reptiles. Human infections with VEE virus were widespread, occurred nearly uniformly in both sexes and were associated with length and place of residence in Almirante. The accumulated evidence suggests that VEE is endemic in Almirante, Panama; that rodents, especially the cotton rat (Sigmodon hispidus), are important reservoirs; and that Culex (Melanoconion) mosquitoes, in particular, C. (M.) taeniopus, are the most efficient vectors of this virus in the area.

A Reinterpretation of the Reproductive Cycle and Demography of the Salamander Desmognathus ochrophaeus

and Charles W. Myers for their suggestions and assistance in the field. I especially thank the latter for the photographs for Figs. 9 and 11. Field and laboratory studies were made possible by support from the National Science Foundation (Grants GB-1441 and GB-5818), and field studies in Panama were carried out under the auspices of a grant from the National Institutes of Health (NIH GM-12020) in co-operation with the Gorgas Memorial Laboratory in Panama.