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At least 217 records · Page 12Linked to original sources
PubMed1978

Venezuelan encephalitis virus infection in neotropical bats. I. Natural infection in a Guatemalan enzootic focus.

A serological survey of 939 Neotropical bats of 22 species from an enzootic focus of Venezuelan encephalitis (VE) virus on the Pacific lowlands of Guatemala during 1971--1975 revealed VE virus specific antibodies in seven species, three belonging to the genus Artibeus. VE virus was isolated from the blood of one Uroderma bilobatum. Antibody frequency was considerably lower in bats than in terrestrial mammals, and tended to vary within any given species from locality to locality and from year to year. At the village of La Avellana where VE virus was most active, antibody rates in the two best-sampled Artibeus species were 0.14 in 1971, 0.11 in 1972, 0.03 in 1973, and 0.11 in 1975. The positive rate of 0.10 over all years at La Avellana for the genus Artibeus suggests that these and possibly other bats regularly are infected by VE virus, and may possibly serve as alternate hosts to maintain virus circulation if most terrestrial animals become immune.

Animals↗
PubMed1978

Venezuelan encephalitis virus infection in neotropical bats. II. Experimental infections.

Eighty-nine Neotropical bats of five species were inoculated subcutaneously with epizootic or enzootic strains of Venezuelan encephalitis (VE) virus. Viremia was detected in 92.5% of all bats, but no illness attributable to virus infection was observed. Detectable viremias averaged slightly over 4 days in Artibeus jamaicensis and A. lituratus, and 2.8 days in Phyllostomus discolor, and maximal viremia titers in these three species averaged 6.9, 6.6, and 4.6 log10 SMicLD50 per ml of blood, respectively. In general Artibeus developed and maintained detectable levels of both hemagglutination-inhibition (HI) and neutralizing antibody for as long as tested (up to 506 days), although HI antibody to enzootic VE virus strains disappeared in some A. lituratus. The detectable antibody response of P. discolor was slower and of lower magnitude and shorter duration than that of Artibeus, although individual P. discolor which had lost detectable HI and N antibody resisted challenge. Vertical passage of antibody was observed in three A. lituratus offspring. Artibeus jamaicensis were found to be only slightly less susceptible to VE virus infection than a U.S. subspecies of the cotton rat (Sigmodon hispidus). No virus was recovered by mouse inoculation of organ pools of bats killed as early as 2 days and as late as 299 days after the last day of detectable viremia.

Animals↗
PubMed1978

Venezuelan encephalitis virus infection in neotropical bats. III. Experimental studies on virus excretion and non-arthropod transmission.

A total of 80 Neotropical bats of five species was inoculated with one of four strains of Venezuelan encephalitis (VE) virus. Virus was detected in the oropharynges of 56% of bats, and most regularly in Artibeus jamaicensis (75%). Titers of virus in oropharyngeal secretions were occasionally very high (8.5 log10 SMicLD50/ml in one A. jamaicensis). Only 2 of 123 urine samples from 50 bats and 2 of 86 fecal samples from 46 bats yielded VE virus. No contact or aerosol virus transmission from bat to bat was detected. VE virus passed transplacentally from two infected mothers to their fetuses, which were aborted. Virus did not pass from one infected mother to her nursing young.

Animals↗
PubMed1993

Characterization of Anopheles pseudopunctipennis sensu lato from three countries of neotropical America from variation in allozymes and ribosomal DNA.

Enzyme electrophoresis and restriction fragment length polymorphism (RFLP) analysis of Anopheles pseudopunctipennis sensu lato from nine isolated populations in neotropical America confirmed previous observations that it constitutes a species complex. Electrophoretic studies showed fixed differences at two enzyme loci, glycerol dehydrogenase (Gcd) and phosphoglucomutase (Pgm), suggesting limited or no gene flow between populations from Mexico and South America. In addition, analysis of genetic distance showed two distinctive clusters, one from Mexico and the other from South America, separated at a Nei's distance level of 0.13, a value consistent in magnitude with that of other anopheline sibling species. The RFLP analysis revealed the presence of a ribosomal DNA fragment in Mexican strains that was absent in strains from South America. Two species have been identified through these studies, one provisionally named An. pseudopunctipennis A, a species from central Mexico, and the other An. pseudopunctipennis B, for the species found in the interAndean valleys and Andean slopes in regions of Peru and Bolivia. This research provides information required to elucidate the status of the different species of the An. pseudopunctipennis complex as vectors of malaria in the Americas.

Alleles↗
PubMed1998

Neotropical echinococcosis in Suriname: Echinococcus oligarthrus in the orbit and Echinococcus vogeli in the abdomen.

This paper reports two cases of neotropical echinococcosis caused by Echinococcus oligarthrus and E. vogeli, neither of which has been reported from Suriname. Case 1, a six-year-old boy, presented a 15 x 25 mm retro-ocular cystic tumor (observed by ultrasound, computed tomography scan, and magnetic resonance imaging) causing exophthalmia, chemosis, palpebral ptosis, and blindness of the left eye. Of two tentative diagnoses, Echinococcus cyst or dermoid tumor, the former was shown to be correct at surgery when a clear liquid and detached protoscoleces were aspirated. Rostellar hooks of the protoscolex were characteristic of E. oligarthrus. Case 2, a 41-year-old man, had polycystic masses excised from the liver and abdomen. A presurgery diagnosis of E. vogeli infection was made due to calcifications seen in the lesions, positive serology, residence of the patient in the tropical forest, and later by the size and shape of rostellar hooks. The presence of these two parasites in one of the former Guianas is not surprising; both species are endemic in tropical forest in Central and South America wherever people have not exterminated wild canids, especially the bush dog, (Speothos venaticus), and felids (wild cats of several species), along with pacas, agoutis, and other rodents that serve as intermediate host of these two cestodes. Eighty-six cases of polycystic echinococcosis are known in people from 11 countries from Nicaragua to Argentina: 32 due to E. vogeli, three to E. oligarthrus, and 51 for which determination of the species was not possible because the hooks of the protoscolex were not found or described. Research to elucidate aspects of transmission of E. vogeli and E. oligarthrus is of practical importance for defining measures for preventing the severe and frequently fatal illnesses caused by these two cestodes.

Abdomen↗
PubMed2002

Emergence of a new neotropical malaria vector facilitated by human migration and changes in land use.

In a region of northeastern Amazonia, we find a species previously of minor importance, Anopheles marajoara, to be the principal malaria vector. In a total of five collections during 1996-97 in three replicated sites near the city of Macapá, Amapá state, this species occurs in much greater abundance compared with the presumed vector Anopheles darlingi. Also, a significantly higher proportion of An. marajoara is infected with malaria parasites, determined by the ELISA technique. This appears to be the result of increased abundance of An. marajoara due to alterations in land use, invasion of its primary breeding sites by human immigrants, and its anthropophilic behavior. This discovery highlights one of the challenges of Neotropical malaria control, namely that the targeting of specific vectors may be complicated by a changing mosaic of different locally important vectors and their interactions with human populations.

Animals↗
PubMed1995

Serologic survey of neotropical bats in Guatemala for virus antibodies.

Neotropical bats were collected from different life zones in Guatemala in 1983 and 1984 to determine the presence and distribution of antibody against 10 viruses. Bats were collected with mist nets at 13 sites in eight departments and 332 serum specimens were obtained for testing for neutralizing (N) antibody by the plaque-reduction neutralization test. Eighty-seven (26%) of the 332 bats from 16 (38%) of 42 bat species sampled were serologically positive for five of six arboviruses and for two other viruses tested. Antibodies against Venezuelan equine encephalitis (VEE) variant I-A/B, eastern equine encephalitis, western equine encephalitis, St. Louis encephalitis, vesicular stomatitis, Tacaribe, and Rio Bravo viruses were detected in resident species of bats. However, N antibodies against the enzootic strain of VEE (Mena II, variant I-E) or Nepuyo viruses were not detected.

Animals↗
PubMed1999

Molecular population genetics of the primary neotropical malaria vector Anopheles darlingi using mtDNA.

Samples of the neotropical malaria vector Anopheles darlingi from Bolivia, Brazil, and Venezuela were analyzed to test for differences in mitochondrial haplotype frequencies. With the use of molecular variance components and F-statistics, significant genetic variability of An. darlingi was found apportioned primarily among populations within regions or within populations, with regions defined either as biomes (n = 5) or ecoregions (n = 2). The Mantel analysis resulted in a significant correlation [Prob (r) = 0.009] between genetic and geographic distances, evidence that these populations are genetically isolated by distance. Such isolation could reflect differences in phenotypes for factors affecting vector capacity.

Animals↗
PubMed2001

[Reports in Pteridaceae (Filacales) family in the Neotropics].

Several contributions to the Neotropical pteridophyte flora are made in this paper with the range extensions for four species of Adiantum, two species of Doryopteris and one species of Eriosorus. The species concerned are: A. polyphyllum Willd. for Nicaragua and Costa Rica; A. trichochlaenum Mickel et Beitel for Guatemala and Costa Rica; A. villosissimum Mett. ex Kuhn for Costa Rica; A. wilesianum Hook. for Nicaragua; D. nobilis (T. Moore) C. Chr. for Costa Rica, Colombia and Venezuela; D. redivida Fée for Panama; and E. hirtus (Kunth) Copel. for Costa Rica. The concept of D. pedata (L.) Fée is redefined.

Pteridaceae↗
PubMed2001

[New species, newly used names and new ranges of tree ferns (Filicales: Cyatheaceae) in the Neotropics].

Two new species are described for the Neotropics, four species are newly accepted, and four species and one variety are reported. The new species are: Cyathea grayumii A. Rojas and C. panamensis A. Rojas. Cyathea alfonsiana L. D. Gómez, C. holdridgeana Nisman & L. D. Gómez, C. onusta H. Christ and C. squarrosa (Rosenst.) Domin are recognized; Cnemidaria coclena Stolze, Cyathea andina (H. Karst.) Domin, C. caracasana var. meridensis (H. Karst.) R. M. Tryon, C. macrosora (Baker) Domin and C. pseudonanna (L. D. Gómez) Lellinger are reported from Costa Rica and Panama.

Costa Rica↗
PubMed2001

Effect of storage temperatures on growth and survival of Escherichia coli O157: H7 inoculated in foods from a neotropical environment.

Escherichia coli O157: H7 has emerged as a new pathogen and is found worldwide. We studied the effect of several storage temperatures on the survival of this bacterium in common foods from a neotropical environment (Costa Rica) because at least seven clinical cases have been reported from the country, and no epidemiological link or probable food association has been described. High (10(6)-10(8) CFU/ml) and low (10(4)-10(6) CFU/ml) populations of E. coli were inoculated (three replications) in ground meat, chopped cabbage, chicken giblets and pasteurized milk and incubated at 0, 6 and 12 degrees C for 24, 48 and 72 h. Vegetables and milk were also stored at 22 degrees C for the same periods. The E. coli O157: H7 enumeration was done according to the methodology described in the Bacteriological Analytical Manual. Populations of E. coli O157: H7 showed either an increasing or decreasing trend, according to temperature, time or food base. Our data indicate that E. coli O157: H7 is capable of surviving and growing in meat, cabbage, milk and chicken giblets; food items commonly consumed by Costa Ricans.

Animals↗
PubMed2002

Geographic and ontogenic variability in the venom of the neotropical rattlesnake Crotalus durissus: pathophysiological and therapeutic implications.

A comparative study was performed on the venoms of adult specimens of the neotropical rattlesnake, Crotalus durissus, from Guatemala, Costa Rica, Venezuela and Brazil, together with the venom of newborn specimens of C. d. durissus from Costa Rica. Venoms from Brazil (C. d. terrificus) and from newborn specimens of C. d. durissus presented an electrophoretic pattern characterized by the predominance of bands with molecular mass of 36 and 15 kDa, whereas those of adult specimens of C. d. durissus from Guatemala and Costa Rica, and C. d. cumanensis from Venezuela, showed a conspicuous band of 62 kDa, and additional bands of 36, 29 and 15 kDa. Moreover, venoms from C. d. terrificus and C. d. cumanensis showed a prominent band of < 10 kDa that probably corresponds to crotamine, since a 'crotamine-like' activity was detected in these venoms upon intraperitoneal injection in mice. Venoms of C. d. terrificus, C. d cumanensis and newborn C. d. durissus induced higher lethal and myotoxic effects than those of adult C. d. durissus. In contrast, adult C. d. durissus and C. d. cumanensis venoms induced hemorrhage, whereas venoms of C. d. terrificus and newborn C. d. durissus lacked this effect. All venoms showed coagulant effect in plasma, the highest activity being observed in the venom of newborn C. d. durissus. An anti-crotalic antivenom produced by Instituto Butantan (Brazil), using C. d. terrificus venom as antigen, was effective in the neutralization of lethal, myotoxic and coagulant effects of all venoms studied, being ineffective in the neutralization of hemorrhagic activity of the venoms of C. d. cumanensis and C. d. durissus. On the other hand, a polyvalent antivenom produced by Instituto Clodomiro Picado (Costa Rica), using the venoms of C. d. durissus. Bothrops asper and Lachesis stenophrys as antigens, was able to neutralize lethal, myotoxic, coagulant and hemorrhagic effects of C. d. durissus venom, but was ineffective in the neutralization of lethality and myotoxicity of C. d. terrificus, C. d. cumanensis and newborn C. d. durissus venom. The high toxicity of South American and newborn C. d. durissus venoms is related to the presence of high concentrations of the neurotoxic phospholipase A2 complex 'crotoxin'. Accordingly, antivenom from Instituto Butantan has a much higher titer of anti-crotoxin antibodies than antivenom from Instituto Clodomiro Picado. Crotalus durissus represents an example of intraspecies variation in venom composition and pharmacology that has relevant pathophysiologic and therapeutic implications.

Animals↗
PubMed1975

Reproductive biology and postnatal development of the neotropical climbing rat, Tylomys.

Neotropical climbing rats (Tylomys), offspring of animals from Mexico and Panama, were maintained in the Michigan State University Museum-Live Animal Colony for the purpose of collecting data on reproduction. Vaginal smears indicated an estrous cycle 6.8 +/- 0.4 da under natural winter lighting, 12.0 +/- 2.5 da when exposed to a 12:12 light:dark cycle, and 4.3 +/- 0.3 da when utilizing an activity wheel and under a 14:10 lighting scheme. The earliest recorded mating for a female Tylomys was 90 da of age. The gestation period was 40.6 +/- 0.5 da, and there was no statistical difference between the gestation lengths of lactating and non-lactating females. The average litter size was 2.3 with a range of 1-4. Weight at birth averaged 20.2 +/- 0.3 g, or about 8% (litter about 16%) the weight of the adult. The daily instantaneous rate of growth (weight) for the first wk was about 5.6%. Graphs were presented indicating changes with time of weight, total body length, and tail, hind foot, and ear lengths. Young respond to loud noises at 6-14 da of age, and eye opening occurs slightly later, at 7-15 da of age. The young cling tenaciously to the female's nipples nearly continuously for the first 3 wk. Females did not perform any nest-building activities. Weaning occurred at approximately 3-4 wk of age.

Animals↗
PubMedDate not supplied

[Neotropical plant morphology].

An analysis on plant morphology and the sources that are important to the morphologic interpretations is done. An additional analysis is presented on all published papers in this subject by the Revista de Biología Tropical since its foundation, as well as its contribution to the plant morphology development in the neotropics.

Bibliometrics↗
PubMedDate not supplied

New species, new combinations and new distributions in neotropical species of Elaphoglossum (Lomariopsidaceae).

More new species, new combinations and new distributions are made in the large and difficult genus Elaphoglossum in Neotropic. Ten new species are described, this are: Elaphoglossum adrianae A. Rojas, E. betancuri A. Rojas, E. caridadae A. Rojas, E. glabromarginatum A. Rojas, E. kessleri A. Rojas, E. macdougalii A. Rojas, E. paramicola A. Rojas, E. paxense A. Rojas, E. pseudoherminieri A. Rojas and E. solomonii A. Rojas. Three species are combined, this are: Elaphoglossum beitelii (Mickel) A. Rojas, E. curvans (Kunze) A. Rojas and E. eutecnum (Mickel) A. Rojas. Finally, 86 species are reported from other countries and some species names are synonymized.

Costa Rica↗
PubMed2005

Ecological adaptation and species recognition drives vocal evolution in neotropical suboscine birds.

Given that evolutionary divergence in mating signals leads to reproductive isolation in numerous animal taxa, understanding what drives signal divergence is fundamental to our understanding of speciation. Mating signals are thought to diverge via several processes, including (1) as a by-product of morphological adaptation, (2) through direct adaptation to the signaling environment, or (3) to facilitate species recognition. According to the first two hypotheses, birdsongs diversify in different foraging niches and habitats as a product of selection for optimal morphology and efficient sound transmission, respectively. According to the third hypothesis, they diversify as a result of selection against maladaptive hybridization. In this study I test all three hypotheses by examining the influence of morphology, acoustic environment, and the presence of closely related congeners on song structure in 163 species of antbird (Thamnophilidae). Unlike oscine passerines, these Neotropical suboscines make ideal subjects because they develop their songs without learning. In other words, patterns of vocal divergence are not complicated by cultural evolution. In support of the morphological adaptation hypothesis, body mass correlates with the acoustic frequency of songs, and bill size with temporal patterning. These relationships were robust, even when controlling for phylogenetic inertia using independent contrasts, suggesting that there has been correlated evolution between morphological and acoustic traits. The results also support the acoustic adaptation hypothesis: birds which habitually sing in the understory and canopy produce higher-pitched songs than those that sing in the midstory, suggesting that song structure is related to the sound transmission properties of different habitat strata. Finally, the songs of sympatric pairs of closely related species are more divergent than those of allopatric pairs, as predicted by the species recognition hypothesis. To my knowledge, these data provide the first direct evidence that species recognition and ecological adaptation operate in tandem, and that the interplay between these factors drives the evolution of mating signals in suboscine birds.

Acoustics↗
PubMed2005

Marine radiations at small geographic scales: speciation in neotropical reef gobies (Elacatinus).

Studies of speciation in the marine environment have historically compared broad-scale distributions and estimated larval dispersal potential to infer the geographic barriers responsible for allopatric speciation. However, many marine clades show high species diversity in geographically restricted areas where barriers are not obvious and estimated dispersal potential should bring many sister taxa into contact. Genetic differentiation at small (separation < 1000 km) spatial scales could facilitate speciation by mechanisms other than the gradual accumulation of reproductive isolation during extended allopatry, such as ecological adaptation to local environmental conditions or the rapid evolution of genes tied to mate recognition, but the role of each of these possibilities has not been simultaneously explored for any species-rich marine taxon. Here, we develop a robust phylogenetic framework for 31 taxa from a species-rich group of Neotropical reef fishes (Gobiidae: Elacatinus) using 3230 bp from one mitochondrial and two nuclear gene regions. We use this framework to explore the contribution of large- and small-scale geographic isolation, ecological differentiation, and coloration toward the formation and maintenance of species. Although species of Elacatinus occur on both sides of the Isthmus of Panama, no sister species are separated by this barrier. Instead, our results indicate that sister taxa occur within oceans. Sister taxa usually differ by coloration, and more distantly related sympatric species frequently differ by resource use. This suggests that some combination of coloration and ecological differences may facilitate assortative mating at range boundaries or in sympatry. Overall, speciation in Elacatinus is consistent with a model of recurring adaptive radiations in stages taking place at small geographic scales.

Animals↗
PubMed2005

Evaluation of the neotropical stingless bee Melipona quadrifasciata (Hymenoptera: Apidae) as pollinator of greenhouse tomatoes.

The Neotropical stingless bee Melipona quadrifasciata Lepeletier was evaluated for pollinating tomatoes (variety Rodas; long-life hybrid) in greenhouses under plastic and with a hydroponic system and "organic concepts" in Minas Gerais State, Brazil. Flowers not pollinated did not set any fruit. Pollination by bees plus manual pollination did not differ from either bee or manual pollination. Maximum fruit diameter, fruit height, and roundness (quotient between maximum fruit diameter and fruit height) were not significantly different between treatments, but fruit visited by M. quadrifasciata had 10.8% less seeds (dry mass) than manual pollination. This apparently low efficiency of M. quadrifasciata pollination was attributed to the overlap of only 30 min between highest bee foraging activity and highest flower stigma receptivity. Thus, it was concluded that M. quadrifasciata is a feasible pollinator of greenhouse tomatoes because of 1) the observed increase in fruit quality with lower mechanical injury than traditional manual pollination, 2) no significant decrease in fruit size, and 3) high price of such product in the market. Some considerations for sustainable use of M. quadrifasciata as greenhouse pollinator are presented. Although techniques for keeping captive colonies of M. quadrifasciata are currently available, the sole current method for acquiring new colonies is removing them from the forest, and if demand was created for large numbers of colonies for commercial use, techniques for captive rearing must be developed to prevent serious declines in wild populations.

Agriculture↗