RESUMO
Honduran dwarf mistletoe (Arceuthobium hondurense Hawksw. & Wiens) is a rare dwarf mistletoe previously known only from Honduras (1,2). In March 2000 we collected a dwarf mistletoe from approximately 7 km west of San Cristobal de las Casas, Chiapas, Mexico near Route 190 (elevation 2,440 m), which was morphologically similar to A. hondurense (1). This population had initially been classified as A. nigrumHawksw. & Wiens (1). However, our morphological measurements and analysis of nuclear rDNA ITS sequences of A. hondurense plants from Honduras (GenBank No. AF325969) and the plants from Chiapas (AF325970) have confirmed that the Chiapan population is A. hondurense and not A. nigrum. An additional population of A. hondurense was discovered in Chiapas approximately 11 km west of Oxchuc near Route 186 (elevation 2160 m). Both of the Chiapan populations of A. hondurense were parasitizing Pinus tecunumanii(Schw.) Eguiluz et Perry. Specimens of A. hondurense from Chiapas were deposited at the Deaver Herbarium, Northern Arizona University, Flagstaff. This is the first report of A. hondurense in Mexico and extends its known distribution from northwestern Honduras (3) by approximately 500 km. Although A. hondurense has not been observed in the pine forests of Guatemala, it is probable that it also occurs there (1). References: (1) F. G. Hawksworth and D. Wiens. 1996. Dwarf Mistletoes: Biology, Pathology, and Systematics. USDA Agric. Handb. 709. (2) R. Mathiasen et al. Phytologia 36:211, 1998. (3) R. Mathiasen et al. Plant Dis. 84:372, 2000.
RESUMO
The mistletoe Psittacanthus angustifolius Kuijt (Loranthaceae) is a common parasite of pines in Honduras (2). In March we observed this mistletoe parasitizing a pine that Farjon and Styles (1) have classified as Pinus tecunumanii Eguiluz & J. P. Perry 4 km south of Jitotol, Chiapas, Mexico. The taxonomy of this host in Chiapas is controversial as Perry (3) classifies the Chiapas populations of this pine as Pinus oocarpa var. ochoterenai Martinez. We also observed P. angustifolius on P. oocarpa Schiede 4 km north of Jitotol. In addition, we found this mistletoe parasitizing Pinus maximinoi H. E. Moore approximately 15 km west of Ocosingo, Chiapas. In Guatemala, we observed P. angustifolius on P. oocarpa at several locations north and south of La Cumbre, Department Baja Verapaz. This mistletoe appears to be less common in Chiapas and Guatemala than it is in Honduras. We did not observe this mistletoe damaging its pine hosts in Mexico or Guatemala. This is the first report of P. angustifolius in both Mexico and Guatemala and the first report of this mistletoe on Pinus tecunumanii (or Pinus oocarpa var. ochoterenai). Specimens of P. angustifolius from the above pine hosts have been deposited at the Deaver Herbarium, Northern Arizona University, Flagstaff. References: (1) A. Farjon and B. Styles. Pinus (Pinaceae), Flora Neotropica, Monogr. 75, New York Botanical Garden, 1997. (2) Mathiasen et al. Plant Dis. 84:203, 2000. (3) J. Perry. The Pines of Mexico and Central America, Timber Press, Portland, Oregon, 1991.
RESUMO
"Norwalk-like viruses" (NLVs) are a common cause of epidemic gastroenteritis in adults and children in developed countries. However, little is known about the role of NLVs in endemic pediatric gastroenteritis in developing countries. We sequenced Genogroup I and II NLV reverse transcription-polymerase chain reaction (RT-PCR) products from an 81-nucleotide region of the viral RNA polymerase gene to examine the molecular epidemiology of NLV infection in children younger than 5 years of age in Forteleza, Ceará, Brazil. NLV-positive PCR products were obtained from stool specimens collected over a 16-month period (1990-1991) from diarrhea cases and controls in a cohort of 120 children in an urban shantytown and from a study in the same city of hospitalized children with persistent diarrhea. Eight unique strains were detected in 15 specimens from 10 cohort children and in two hospital specimens. Nucleotide identity between the strains (5 Genogroup I, 3 Genogroup II) ranged from 63% to 88%. We designated these strains BraV1-8, for Brazil virus 1-8. The degree of genomic diversity of NLV strains we identified in this cohort during a short time period suggests multiple foci of infection within the community. Furthermore, sequence analysis of strains from two children with multiple symptomatic NLV infections indicates that infection with one strain was not protective against subsequent infection with a different strain in the same genogroup. These findings have implications for vaccine development and the prevention of pediatric gastroenteritis in developing countries.
Assuntos
Infecções por Caliciviridae/virologia , Variação Genética , Genoma Viral , Vírus Norwalk/genética , Brasil/epidemiologia , Infecções por Caliciviridae/sangue , Infecções por Caliciviridae/epidemiologia , Estudos de Coortes , Fezes/virologia , Gastroenterite/virologia , Humanos , Lactente , Vírus Norwalk/classificação , Vírus Norwalk/imunologia , Filogenia , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alinhamento de Sequência , Análise de Sequência de DNA , Testes SorológicosRESUMO
Thirty-three Argentinian patients infected with hepatitis C virus (HCV) were studied for viral genotyping. The patients included 10 hemophiliac and 4 polytransfused children and 19 adults: 3 polytransfused, 7 dialyzed and 9 sporadic cases. Core-based genotyping permitted the classification of 31 samples. Genotypes II, I and V were the most frequent: 21 (63.6%), 16 (48.4%) and 10 (30.3%) of the 33 patients, respectively. Only one polytransfused patient carried genotype IV. Genotype II was detected in 7 out of 9 sporadic cases. Thirteen patients (39.3%) were coinfected with two genotypes, and 2 others were coinfected with three genotypes. The remaining 2 samples which could not be typed were characterized following the restriction fragment length polymorphism (RFLP) method, and were classified as type 1. One of these had two consecutive transitional mutations in the 5' untranslated region (5' UTR).