Serological Properties Research Articles

Characterization of a potyvirus from eggplant (Solanum melongena) as a strain of potato virus Y by N‐terminal serology and sequence relationships

A potyvirus (eggplant mottle virus, EMoV) causing mosaic mottling in eggplant (Solanum melongena) was characterized on the basis of biological, serological and partial nucleotide sequence properties. EMoV infected Chenopodium amaranticolor and members of the Solanaceae. Polyclonal antiserum against EMoV showed antigenic relationship with henbane mosaic potyvirus (HMV) and potato Y potyvirus (PVY). Virus‐specific antibodies directed to the N‐terminal region of EMoV cross‐reacted only with PVY. Determination and comparison of nucleotide sequence of the coat protein (CP) and the 3′‐untranslated region (UTR) of EMoV with other potyviruses showed that the level of homology was highest with PVY isolates. Comparative sequence analyses of the CP amino acid and 3′‐UTR sequences with distinct PVY isolates placed EMoV within the PVYO subgroup.

An Immunity (QL3) Breaking Strain of Sorghum Mosaic Potyvirus in India.

Sorghum (Sorghum bicolor) line Tx2786 is immune to strains or isolates of sorghum mosaic potyvirus (SrMV strains SCH and SCH) but susceptible to strains of maize dwarf mosaic (MDMV) and sugarcane mosaic (SCMV) potyviruses (1,2). When grown in proximity to sugarcane, Tx2786 was infected with a virus that caused mosaic and necrotic symptoms during the postrainy season of 1994 (14 to 30°C) at Parbhani (Maharashtra, India). Leaf-dip electron microscopy performed on virus-infected sorghum and sugarcane tissues revealed particles, 720 × 12 nm, typical of a potyvirus. A potyvirus isolate (designated IBS) was readily transmitted mechanically from field-infected sorghum (Tx2786) and sugarcane (Saccharum officinarum cv. Co.740) to 18 glasshouse-grown sorghum inbred lines. All sorghum lines (QL-3 from India and Tx2786), including those resistant to SrMV, SCMV, MDMV, and johnsongrass mosaic potyvirus (JGMV), were infected. IBS caused necrosis in Cargill-40, Hegari, PI-35038, RTx09, Tx2786, QL-3 from India, and Redlan lines and mosaic symptoms in RTx430, SA-394, Atlas, Martin, BTx3048, Caprock, NM-31, QL-11, SCO-175-14E, Rio, and BTx623 lines. Sorghum reactions to sorghum and sugarcane virus isolates were similar. IBS also infected maize (Zea mays cv. African Tall), johnsongrass (S. halepense cv. 81, symptomless infection), and sorghum (S. bicolor cv. CS-3541) but not prosomillet (Panicum miliaceum), fingermillet (Eleusine coracana cv. IE-2540), pearl millet (Pennisetum typhoides cv. NHB-3), or oat (Avena sativa cv. Kent) when sap transmitted. IBS also was transmitted by the corn leaf aphid (Rhopalosiphum maidis) in a nonpersistent manner from sorghum and sugarcane to all 18 sorghum lines in a glasshouse. Based on direct antigen-coating enzyme-linked immunosorbent assay (DAC-ELISA), serologically specific electron microscopy, and Western blot tests, IBS was serologically related to SrMV strains SCH and SCI (2-4) but not to MDMV strains A, D, and E; SCMV strains A, B, D, SC, and MDB; or JGMV type strain from Australia and strain O from Texas (2). IBS induced formation of cytoplasmic cylindrical inclusions consisting of pinwheels associated with long, straight, laminated aggregates (subdivision type II) in sorghum and sugarcane host cells. Purified IBS contained one major polypeptide of 40 kDa and a ribonucleic acid of 3.0 × 106 Da. Polyclonal antiserum to IBS was produced in rabbits and used in DAC-ELISA to confirm the identity of IBS in sugarcane, sorghum lines, and other test plant species. On the basis of biological and serological properties, IBS isolated from field-infected sorghum grain Tx2786 and sugarcane cv. Co.740 is identified as an immunity (QL3) breaking strain of SrMV (SrMV-IBS).

Serological properties and intrinsic antibiotic resistance of soybean bradyrhizobia isolated from Thailand

A group of Bradyrhizobium strains isolated from soybean plants in Thailand did not correspond to any known DNA homology groups of Bradyrhizobium japonicum and Bradyrhizobium elkanii reported by Hollis et al. (J. Gen. Microbiol., 123, 215–222, 1981). To clarify the phenotypic characteristics of the group, serological properties and intrinsic antibiotic resistance (IAR) profile of 94 Thai strains were compared with those of USDA and Japanese strains. Indirect ELISA tests for each Thai strain were performed agaiIl.st polyclonal antisera prepared against 15 USDA standard serotype strains of B. japonicum and B. elkanii. Among the 94 Thai strains tested, 36 which were previously identified as B. elkanii, with the exception of one strain, were strongly responsive to an antiserum prepared against USDA 31. The remaining 58 strains, with the exception of two strains, showed multiple cross reactions which were peculiar to the Thai strains. These serological reaction patterns did not correspond to any known serogroups labeled as B. japonicum and B. elkanii. In the IAR test, the taxonomically unknown Thai soybean bradyrhizobia exhibited a high level of resistance to neomycin (50 µg/mL), polymyxin (50 µg/mL), nalidixic acid (15 µg/mL), and kanamycin (15 µg/mL). Kanamycin could thus be useful in combination with neomycine and nalidixic acid for distinguishing between the unknown Thai strains and strains of B. japonicum and B. elkanii. Our results demonstrated that the unknown Thai strains were serologically and IAR-phenotypically remote from both B. japonicum and B. elkanii.

The subtilisins of fungal pathogens of insects, nematodes and plants: distribution and variation

The extracellular subtilisin-like protease activity of several fungal pathogens of nematodes, insects and plants was recorded after batch cultivation. Nematophagous and entomophagous isolates of Verticillium, Paecilomyces, Beauveria and Metarhizium produced Suc-(Ala) 2 -Pro-Phe-pNA hydrolysing enzymes that differed in serological properties based on Western blot analysis with polyclonal antibodies. The antibodies used were raised against the main subtilisin-like proteases from one species from each of the four genera. From each strain of V. chlamydosporium tested, between one and four isoforms with different pI values were separated by isoelectric focusing and visualized by enzymoblots. The occurrence of multiple isoforms with unique N-terminal sequences in single strains might suggest the presence of subtilisin gene families. Using as a probe a fragment of the Pr1 gene from M. anisopliae , RFLPs were observed that confirmed qualitative differences between subtilisin-like genes within and between species. In contrast to these pathogens of invertebrates, plant-pathogenic species of Verticillium did not produce subtilisin-like proteases, nor were homologous genes detected. Such activity, however, and the corresponding genes, were detected in species weakly pathogenic to plants, or saprotrophs.

Acquisition of new capsular genes among clinical isolates of antibiotic-resistant Streptococcus pneumoniae.

Antibiotic-resistant clones of Streptococcus pneumoniae are recognizable through a combination of unique molecular, microbiological, and serological properties. In the course of surveillance of epidemic clones of S. pneumoniae, several isolates were identified that shared the clone-specific pulsed-field gel electrophoretic (PFGE) pattern and antibiotype but expressed serotypes atypical for the particular clone. A selected group of isolates belonging to the Spanish/USA clone but expressing serotypes 19, 14, or 3, instead of the expected serotype 23F, were tested using DNA probes for each of the 18 open reading frames (ORFs) of the 23F capsular locus. In no case were there any 23F-specific genes retained, with the possible exception of genes already known to be common to the capsular loci involved. Analysis of the sequence of the capsular locus of a penicillin-resistant serotype 23F isolate from Mexico showed that part of the cpsA gene of this strain, as well as genes cpsQ and cpsR, had high degrees of identity to the sequence of the homologous genes in isolates expressing serotype 19F. The capsular locus of this Mexican strain may have originated from an in vivo capsular switch event in which the original 19F locus was replaced by 23F-specific capsular genes.

Occurrence, Distribution and Relative Importance of Viruses Infecting Hot Pepper and Tomato in the Major Growing Areas of Ethiopia

AbstractHot pepper and tomato fields in the main growing areas in the Rift Valley and the west of Ethiopia were surveyed for virus infections in 1994. A total of 286 samples from hot pepper and 222 samples from tomato plants and associated Datura stramonium L. and Nicandra physalodes Gaertn. weeds with symptoms suggestive of virus infections were collected and analysed using electron microscopy, serology and test plant reactions. Potato virus Y (PVY), Ethiopian pepper mottle virus (EPMV), pepper veinal mottle virus (PVMV) and tomato mosaic virus (ToMV) were detected in hot pepper samples while tomato samples were shown to be infected with tomato mild mottle virus (TMMV), PVY and ToMV. The most widespread and predominant viruses which also occurred frequently in mixed infections were PVY and EPMV in hot pepper and PVY and TMMV in tomato. TMMV was also found in many samples of D. stramonium and N. physalodes. ToMV was identified in only few samples from both crops in the Rift Valley by its characteristic particle morphology, serological properties and symptomatology. PVMV was found in hot pepper samples only from western Ethiopia, but no natural infection of tomato with this virus was revealed. This is the first report on the natural occurrence of TMMV in tomato, D. stramonium and N. physalodes, as well as of ToMV in hot pepper and tomato in Ethiopia.

Serological relationship of some V-factor dependent Pasteurellaceae (Haemophilus sp.) from guineapigs and rabbits.

Culture of guinea pig and rabbit respiratory tracts for bacteria using X- (haemin) and V- (NAD) factor in agar media detected infection by V-factor dependent Pasteurellaceae (Haemophilus sp.) in three colonies of guinea pigs and a group of rabbits. The 12 Haemophilus strains comprised three API NH codes classed as Haemophilus parainfluenzae and two codes classed as Haemophilus aphrophilus/paraphrophilus. Six cell wall lipid profiles were detected, but these were not related to API NH codes. Both bacteriological properties were used to select strains for serological studies but any relationship between bacteriological and serological properties of the Haemophilus strains was not evident. Varying serological relationships occurred between the newly isolated Haemophilus strains, [Pasteurella] pneumotropica NCTC 8284 and Haemophilus strains previously isolated from rats.

Properties of a Cowpea Mild Mottle Virus (CPMMV) Isolate from Eggplant in Jordan and Evidence for Biological and Serological Differences Between CPMMV Isolates from Leguminons and Solanaceous Hosts

AbstractA virus isolate from an eggplant (Solanum melongena) showing a mild leaf mosaic had slightly curved filamentous particles with a normal length of 653 nm, a capsid protein size of about 32 kDa and a narrow host range restricted largely to the Solanaceae, It was transmitted by the whitefly Bemisia tabaci in a nonpersistent manner but not by the aphid Mvzus persicae. Its particle morphology, vector transmission and strong reactions in immunoelectron microscopic (IEM) decoration tests with antisera to cowpea mild mottle virus (CPMMV) indicated that it is a CPMMV isolate. Particles of the isolate were weakly decorated when antisera to two carlaviruses, carnation latent virus and a distinct but incompletely described carlavirus from Helleborus, were used in I EM but not with 19 antisera to other carlaviruses. When the isolate was compared in host range and serological properties with another CPMMV isolate from tomato in Israel and two legume isolates of CPMMV, the two isolates originating from the solanaceous hosts in Jordan and Israel appeared to be very similar but clearly distinct from the two legume isolates from India and West Africa. In IEM decoration experiments, a legume isolate of CPMMV from Brazil was serologically distantly related to the two other legume isolates but strikingly dissimilar to the Jordanian isolate. Moreover, the isolates from Jordan and Israel differed from the legume isolates by inducing only banded or nonbanded virion aggregates but no brush‐like virion aggregates reported to be characteristic of legume isolates of CPMMV from Africa, Thailand and Brazil. Under the conditions of the present study brush‐like inclusiotis were also found with the Indiati and West African isolates. The incidence of the virus was higher in the autumn than spring growing season. Solanum incanum was identified as a possible perennial reservoir of CPMMV during the summer when the Jordan valley is virtually free from cultivated eggplants

Natural infection with raspberry bushy dwarf virus (RBDV) of the putatively RBDV‐resistant red raspberry cultivar Glen Moy, and the demonstration that it does not contain the RBDV resistance gene, Bu

Summary.When released to commerce in 1981, the red raspberry cv. Glen Moy was reported to be immune to the Scottish type isolate of raspberry bushy dwarf virus (RBDV‐D200). Field observations of this cultivar in localities where RBDV was prevalent tended to support this claim of its resistance, but in the past 6–10 yr, RBDV infection has been reported in this cultivar in Australasia, USA and in several commercial crops in England. Therefore, experiments were made to investigate the reason(s) for this apparent anomaly using RBDV‐infected material, putatively of cv. Glen Moy, from two locations in southern England and one each from Australia, New Zealand (NZ) and the USA. Genetic fingerprinting of genomic DNA from samples of these five RBDV‐infected raspberry sources confirmed their identity as cv. Glen Moy. Comparisons of some serological and genomic properties of the five Glen Moy RBDV isolates indicated that, whilst they shared many properties with previously well characterised isolates of this virus, they were distinguishable from them. Characterisation of the isolate from NZ maintained in raspberry showed that it did not have a Rubus host range characteristic of resistance‐breaking (RB) isolates, indicating that for this location, and probably also for those of Australia and the USA, RB isolates were not the cause of infection in cv. Glen Moy. When virus‐tested plants of cv. Glen Moy and 45 progeny seedlings from the cross between cv. Glen Moy and the RBDV‐susceptible cv. Autumn Bliss were graft inoculated with RBDV‐D200, all grafted plants became infected indicating that cv. Glen Moy does not contain the RBDV resistance gene, Bu. Possible reasons for the previously reported resistance of cv. Glen Moy to RBDV are discussed.

Unsatisfactory Detection of an in vivo Haemolytic Anti‐Vel by the Gel Test

A patient experienced a severe haemolytic transfusion reaction. Neither the haemolytic property nor the specificity of the causative antibody had been sufficiently recognised when performing a microcolumn gel test. Subsequent to the transfusion reaction, the serological property and specificity of the causative antibody were analysed. Tube and gel test methods were compared, as were various reagent red cell specimens and their constituents. A haemolytic anti-Vel was detected in the tube test. In contrast, the particular commercial gel test kit used did not reveal the haemolytic property or specificity of the antibody. Our experiments suggest that this was apparently due to the presence of EDTA in the low ionic strength saline solution of the test kit. In rare cases life-treatening haemolytic activity of an irregular blood group antibody may be undetected by a commericial microcolum gel test kit in which EDTA is a constituent.

Unsatisfactory Detection of an in vivo Haemolytic Anti-Vel by the Gel Test

Background and Objectives: A patient experienced a severe haemolytic transfusion reaction. Neither the haemolytic property nor the specificity of the causative antibody had been sufficiently recognised when performing a microcolumn gel test. Materials and Methods: Subsequent to the transfusion reaction, the serological property and specificity of the causative antibody were analysed. Tube and gel test methods were compared, as were various reagent red cell specimens and their constituents. Results: A haemolytic anti-Vel was detected in the tube test. In contrast, the particular commercial gel test kit used did not reveal the haemolytic property or specificity of the antibody. Our experiments suggest that this was apparently due to the presence of EDTA in the low ionic strength saline solution of the test kit. Conclusion: In rare cases life-threatening haemolytic activity of an irregular blood group antibody may be undetected by a commercial microcolumn gel test kit in which EDTA is a constituent.

Distribution and incidence of faba bean necrotic yellows virus in Jordan

Faba bean necrotic yellows virus (FBNYV) was isolated from naturally infected faba bean plants in Jordan. The identification was based on host range, mode of transmission, symptomatology and serological properties. FBNYV occurred naturally in several leguminous crops including cultivated legumes and wild forage legumes, such as species of Medicago, Trifolium and Lathyrus. and infected other plant species belonging to the Malvaceae, such as Malva parviflora and Hibiscus esculentus. Such hosts may act as important natural reservoirs for both the virus and its aphid vectors. This is the first report of infection of M. parviflora and H. esculentus with FBNYV. The virus was not recovered from samples taken from some cultivated crops, including squash, cucumber, tomato, eggplant and pepper, growing near to faba bean fields. Also, it was not detected in commercial faba bean seeds collected from local companies or in seeds collected from infected faba bean plants. It was transmitted efficiently by Aphis craccivora. Serological testing of 1392 samples from faba beans showing virus‐like symptoms and collected randomly from 16 locations (fields) in the Jordan Valley and Jarash areas showed that FBNYV occurred in 54.5% of the samples. These results indicate that FBNYV was an important pathogen of beans during the growing season of 1996 in Jordan.

Subgroup Determination of Bulgarian Isolates of Cucumber Mosaic Virus and the Presence of Satellite RNAs.

Cucumber mosaic virus (CMV) is one of the most important viruses in Bulgaria, causing severe losses to agriculture, but little is known about the occurrence and distribution of subgroups within the country or the presence of satellite RNAs (satRNAs). Samples showing typical symptoms (mild to severe mosaic, vein clearing, vein necrosis, leaf deformation, stunting, and fruit necrosis) on several important crops (tomato, cucumber, pepper, bean, courgette, and tobacco) were collected from the main agricultural regions of the country. Isolates were maintained by sap inoculation in tobacco plants. Total RNAs were isolated from 38 samples (including two from bean) and used in reverse transcription-polymerase chain reaction (RT-PCR) assay with primers corresponding to the coat protein (CP) gene of RNA3 (3). A single strong band, 870 bp in length, was produced from all these samples. Amplified products were analyzed for subgroup differentiation by digestion with the restriction endonucleases MspI (3), PvuII, and EcoRI. The MspI subgroups 2 and 1 designated by Rizos et al. (3) according to their restriction endonuclease digest data correspond to the subgroups I and II widely used in the literature and based on serology, sequence data, and other properties. In this report, the subgroups are referred to as I and II for the sake of clarity. Isolates in both subgroups were found in all the main regions of Bulgaria. A few variations in MspI and EcoRI digestion patterns were seen, indicating some variability between isolates within subgroups. Only five samples, three from tomato and two from pepper, were found to be subgroup II. Subgroup I isolates were found in all the crops sampled. The PCR product from one representative isolate of each subgroup was cloned and sequenced by standard procedures. Alignment of the nucleotide and predicted amino acid sequences with published sequences of the CMV CP gene confirmed that the amplified products were derived from CMV. A further eight samples from bean gave only weak amplification and digestion of the products suggested they were likely to be subgroup II. However, these samples were unusual in not inducing symptoms in inoculated tobacco and in being difficult to propagate. The nature of these virus isolates is therefore unclear. Only a single occurrence in Bulgaria of satRNA of CMV has been reported (4) but in this study satRNAs were detected by RT-PCR (1) in total plant RNA extracts of 21 of the 38 samples tested. Amplified products of two of them, NB and 146D, were sequenced; comparison with published sequences confirmed that they were derived from CMV satellite. As expected from the symptoms induced by these isolates, a sequence homologous to the domain of satRNA Y responsible for bright yellow mosaic on tobacco (2) was identified in satRNA NB but not in satRNA 146D. satRNAs were not detected in the eight bean samples that had given only weak amplification with the CMV CP gene primers. The results presented here clearly demonstrate the presence of both subgroups of CMV in Bulgaria. Although CMV in Bulgaria has been studied previously by serological methods, no evidence had been found for the presence of subgroup II.

Virulence and molecular polymorphism of Prunus necrotic ringspot virus isolates.

Prunus necrotic ringspot virus (PNRSV) occurs as numerous strains or isolates that vary widely in their pathogenic, biophysical and serological properties. Prior attempts to distinguish pathotypes based upon physical properties have not been successful; our approach was to examine the molecular properties that may distinguish these isolates. The nucleic acid sequence was determined from 1.65 kbp RT-PCR products derived from RNA 3 of seven distinct isolates of PNRSV that differ serologically and in pathology on sweet cherry. Sequence comparisons of ORF 3a (putative movement protein) and ORF 3b (coat protein) revealed single nucleotide and amino acid differences with strong correlations to serology and symptom types (pathotypes). Sequence differences between serotypes and pathotypes were also reflected in the overall phylogenetic relationships between the isolates.

Characterization of a murine monoclonal antibody to Cryptococcus neoformans polysaccharide that is a candidate for human therapeutic studies.

The murine monoclonal antibody (MAb) 18B7 [immunoglobulin G1(kappa)] is in preclinical development for treatment of Cryptococcus neoformans infections. In anticipation of its use in humans, we defined the serological and biological properties of MAb 18B7 in detail. Structural comparison to the related protective MAb 2H1 revealed conservation of the antigen binding site despite several amino acid differences. MAb 18B7 was shown by immunofluorescence and agglutination studies to bind to all four serotypes of C. neoformans, opsonize C. neoformans serotypes A and D, enhance human and mouse effector cell antifungal activity, and activate the complement pathway leading to deposition of complement component 3 (C3) on the cryptococcal capsule. Administration of MAb 18B7 to mice led to rapid clearance of serum cryptococcal antigen and deposition in the liver and spleen. Immunohistochemical studies revealed that MAb 18B7 bound to capsular glucuronoxylomannan in infected mouse tissues. No reactivity of MAb 18B7 with normal human, rat, or mouse tissues was detected. The results show that both the variable and constant regions of MAb 18B7 are biologically functional and support the use of this MAb in human therapeutic trials.

Presence of Vicia graminea lectin- and Vicia unijuga lectin-binding (Vgu) glycoproteins in human fetal membranes and some of their biochemical properties

We have previously reported that Vicia graminea lectin (VGA)- and Vicia unijuga lectin (VUA)-binding glycoproteins (Vgu glycoproteins), malignant tumor-associated antigens, exist in human meconium and amniotic fluid. To examine the origin of Vgu glycoprotein, their presence, some of their chemical and serological properties and their biosynthesis in the human fetal membrane, amnion and chorion laeve and accompanying membrane cells were examined. Perchloric acid-soluble fractions were prepared from human amnion and chorion laeve, after which VUA-binding components (Vgu glycoproteins) were separated by HPLC and affinity chromatography using immobilized VUA. Biosynthesis of the antigens in primary cultured cells prepared from the amnion and chorion laeve were examined by pulse-labeling and immunoprecipitation using immobilized VUA and compared with those in cultured human cancer cells. The results indicated that the serological properties of VUA-binding components in fetal membranes were similar to those of meconium and amniotic fluid, that many molecular species of VUA-binding components were synthesized in amnion and chorion laeve cells and that about 40–50% of antigens synthesized are secreted from cells while antigens synthesized in cultured cancer cells human were hardly secreted with more than 95% of the antigens remaining in the cells. From these results, we concluded that a large part of Vgu glycoproteins found in amniotic fluid is synthesized in cells of the amnion and chorion laeve and secreted into the fluid, and that Vgu glycoproteins synthesized in cancer cells were not secreted, rather they were retained in the cells.

Application of the Human Hepatitis B Virus Core Antigen from Transgenic Tobacco Plants for Serological Diagnosis

Abstract Background and objectives: The aim was to produce HBcAg from plants more cheaply than can be done by other currently available means, and to apply such antigen to immunoassay procedures for pretransfusion testing of donor blood. Materials and methods: Transgenic Nicotiana tabacum cv. SR‐1 plants expressing the human hepatitis B virus (HBV) core antigen (HBcAg) gene were generated by Agrobacterium‐mediated transformation. The recombinant product, called tHBcAg, can assemble itself into a spherical particle with a diameter of 25 to 30 nm, and can maintain two antigenic determinants of HBcAg, namely HBc/α and HBc/β. Partly purified tHBcAg was used in the hemagglutinationinhibition (HI) test, as routinely used by the Japanese Blood Center, to test a panel of 524 blood units taken from HBV‐positive donors. Results: In the HI test, tHBcAg showed serologic properties comparable to that from Escherichia coli, the standard antigen used in the Japanese Blood Center. Conclusions: Transgenic plants can produce reagents for serologic testing and perhaps even such medical materials as oral vaccines.

Serological and biological properties of maize-infecting potyvirus from Zimbabwe

Serological and biological properties of maize-infecting potyvirus from Zimbabwe

Properties of serological group B streptococci of dog, cat and monkey origin.

This study was designed to identify and characterize further Streptococcus agalactiae isolated during routine diagnostics from three diseased dogs and a cat, as well as from the inner organs of a monkey which died on a sepsis with beta-haemolytic streptococci. The cultures could be identified as streptococci of serological group B by cultural, biochemical and serological properties and by restriction fragment length polymorphism analysis of polymerase chain reaction (PCR)-amplified 16S ribosomal DNA. A further characterization of the isolates by serotyping and by determination of antibiotic resistances revealed a close relationship of these isolates to the human biotype of this species.

Arenavirus phylogeny: a new insight.

Arenaviridae is a worldwide distributed family, of enveloped, single stranded, RNA viruses. The arenaviruses were divided in two major groups (Old World and New World), based on serological properties and genetic data, as well as the geographic distribution. In this study the phylogenetic relationship among the members of the Arenaviridae was examined, using the reported genomic sequences. The comparison of the aligned nucleotide sequences of the S RNA and the predicted amino acid sequences of the GPC and N proteins, together with the phylogenetic analysis, strongly suggest a possible kinship of Pichindé and Oliveros viruses, with the Old World arenavirus group. This analysis points at the evolutive relationships between the arenaviruses of the Americas and can be used to evaluate the different hypotheses about their origin.