RESUMEN
The mean age of 80 kala-azar cases was 20. 26 +/- 10.68 years, much higher than previously reported. This higher age incidence is probably related to fall of herd immunity particularly in the young adults resulting from less chance of natural infection during their childhood at such times when kala-azar in India had been largely controlled.
Asunto(s)
Países en Desarrollo , Leishmaniasis Visceral/epidemiología , Adolescente , Adulto , Niño , Preescolar , Estudios Transversales , Femenino , Humanos , Incidencia , India/epidemiología , Lactante , Masculino , Persona de Mediana EdadRESUMEN
The multicopy mini-exon-derived RNA (med RNA) locus of Leishmania donovani was enzymatically amplified by the polymerase chain reaction (PCR). The major 180 bp PCR product contained conserved med RNA gene sequences flanking the variable intergenic spacer from the med RNA gene tandem repeat. The oligonucleotide primers cross-reacted with other Leishmania species. In serial dilution experiments, positivity in the PCR assay was observed down to the genomic DNA equivalent of less than a single Leishmania cell. When the major PCR products from Indian L. donovani isolates were cloned and used as probes in dot hybridization analyses, they discriminated between L. donovani and L. amazonensis, L. major and L. infantum under high stringency conditions. DNA from spleen biopsies and blood samples of confirmed kala azar patients was positive, as were two skin biopsies from patients with post-kala azar dermal leishmaniasis (PKDL). These observations demonstrate that PCR amplification of med RNA intergenic spacers is sufficiently sensitive for clinical diagnosis of kala azar and PKDL, and furthermore, that cloned intergenic spacer probes may be useful for identification and classification of L. donovani.
Asunto(s)
ADN Protozoario/análisis , ADN Ribosómico/análisis , Leishmania donovani/aislamiento & purificación , Leishmaniasis Visceral/diagnóstico , Animales , Secuencia de Bases , Cartilla de ADN , Exones , Humanos , Intrones , Leishmania donovani/genética , Datos de Secuencia Molecular , Sondas de Oligonucleótidos , Reacción en Cadena de la Polimerasa , ARN Ribosómico/genéticaRESUMEN
Indian kala-azar patients have normal numbers of peripheral blood NK cells but impaired functional activity due to decreased binding and lysis of target cells. This impairment of NK activity could not be corrected by exogenous recombinant human alpha or gamma interferon. However, recombinant human interleukin 2 was able to restore this activity by augmenting conjugate formation and lysis of target cells.
Asunto(s)
Interferón Tipo I/farmacología , Interferón gamma/farmacología , Interleucina-2/farmacología , Células Asesinas Naturales/inmunología , Leishmaniasis Visceral/inmunología , Adolescente , Adulto , Niño , Femenino , Humanos , Masculino , Proteínas RecombinantesRESUMEN
Following sequence analysis of a Leishmania donovani kinetoplast DNA (kDNA) minicircle, we have developed synthetic oligonucleotides for use in the polymerase chain reaction (PCR). With these primers, we have amplified L. donovani kDNA from splenic aspirates and blood samples taken from kala-azar patients. Treatment of the samples for PCR requires only limited DNA purification by lysis in SDS, digestion with proteinase K, phenol extraction and ethanol precipitation of the resulting nucleic acid. We have obtained amplified product routinely with DNA prepared from the equivalent of 2.5-25 microliters of splenic aspirate or of 50-500 microliters of blood from infected patients. In dilution experiments a visible product has been obtained on amplification of DNA from the equivalent of 2.5 x 10(-7) microliters of splenic material. We therefore propose the amplification of L. donovani kDNA by PCR as a rapid and highly sensitive method for the diagnosis of kala-azar.