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J Alvar

Publications and source records attributed to J Alvar.

At least 55 records · Page 3Linked to original sources
PubMed1994

Visceral leishmaniasis in Angola due to Leishmania (Leishmania) infantum.

A 26-year-old man from Angola with no history of travel outside the country presented with typical symptoms of visceral leishmaniasis. The parasite was isolated and biochemically characterized using both kinetoplast DNA and nuclear DNA probes and showed a strong homology with Leishmania (Leishmania) donovani sensu lato (s.l.). When the nuclear DNA of the isolate was hybridized with a specific Leishmania (L.) infantum probe, the pattern obtained showed a clear signal with this species. To establish its identity more specifically, this isolate was typed using a 15-system isoenzyme panel and thick-starch gel electrophoresis, and was identified as L. (L.) infantum zymodeme 1 (MAD-1), the most widespread zymodeme in Mediterranean countries. One case of visceral leishmaniasis has been reported in Angola, but this case is the first report of L. (L.) infantum in Africa south of the equator.

Adult↗
PubMed1994

Application and evaluation of QBC malaria diagnosis in a holoendemic area.

Quantitative Buffy Coat Analysis was used in practical diagnosis situations. In the first place, sensitivity and specificity was measured in an active search survey (720 schoolchildren under 10 years of age, in nine field trips) under unfavourable laboratory conditions (onsite school diagnosis being conducted with electricity supplied by a diesel-powered generator). In this group, the QBC-based study revealed sensitivity and specificity ratings of 99.6% and 81.7% respectively. QBC proved 5.5% more sensitive than the thick-film method, but specificity was greater with the latter. QBC returned good results when used in adverse situations, viz., in the absence of air conditioning and with a diesel generator as the only power supply. QBC was used in a passive search survey (hospital group, 618 children) under good laboratory conditions (air conditioning) with patients enrolled in a trial to measure resistance to antimalarial drugs. In this survey we targeted at assessing the efficacy of chloroquine treatment at dose of 25 mg/kg/3 days. QBC proved more sensitive than the thick-film method, detecting - on day 14 of the in vivo test - low parasitaemias that had gone undetected by thick film. Lastly, this study reports on the conversion of QBC readings (parasitaemia per field) into thick-field terms (number of parasites per microliter of blood), with the aim of measuring the degree of recurring parasitaemia.

Acridine Orange↗
PubMed1994

Human subcutaneous dirofilariasis caused by Dirofilaria repens in Ibiza, Spain.

A case of human subcutaneous dirofilariasis contracted in Ibiza, Spain is reported. An incomplete nematode extracted from the eyelid of a woman patient was identified on the basis of its anatomic and histologic characteristics as a nongravid adult female of the species Dirofilaria repens. The subcutaneous location of the worm, together with the epidemiologic data, support this finding.

Adult↗
PubMed1993

Resistance of Plasmodium falciparum to antimalarial drugs in Equatorial Guinea.

One hundred and sixty-six children from Equatorial Guinea, all under 10 years of age and with acute uncomplicated falciparum malaria, were randomly allocated to four groups and treated with one of the following regimens: chloroquine or amodiaquine (25 mg base/kg body weight over 3 days), quinine (8 mg/kg every 8 h for 3 or 5 days), and sulphadoxine-pyrimethamine (25-1.25 mg/kg, in one dose). The parasite clearance rates up to day 14 were 28% with chloroquine, 74% with amodiaquine, and 95% with quinine or sulphadoxine-pyrimethamine. The times required to clear asexual blood forms of Plasmodium falciparum in sensitive cases were 64, 70, 73 and 65 h, respectively. Although quinine and sulphadoxine-pyrimethamine are equally effective, quinine is recommended for treatment of multidrug-resistant malaria in paediatric patients, essentially because of the risk of serious reactions to sulpha drugs. Health providers are, however, encouraged to keep supplies of sulphadoxine-pyrimethamine as an option and to refer patients quickly, if required.

Amodiaquine↗
PubMed1993

Baseline entomological data for a pilot malaria control program in Equatorial Guinea.

Entomological studies conducted on the island of Bioko and the mainland province, Río Muni, in Equatorial Guinea provided baseline data for a pilot malaria control program. The main species collected resting in houses at low density were Anopheles gambiae s.l. Giles and Anopheles funestus Giles. An. gambiae s.l. density increased during the rainy season, whereas An. funestus populations remained stable during both dry and wet seasons. Both species tended to be endophilic and were not collected resting or biting outdoors. Overall, delayed sporozoite rates were about 10% for both species and were highest in the dry season. An. gambiae s.l. from the mainland showed resistance to 4% DDT, but the island population was still susceptible. All populations were completely susceptible to 5% malathion and 0.025% deltamethrin.

Animals↗
PubMed1992

Evidence of the presence of spotted fever group rickettsiae in dogs and dog ticks of the central provinces in Spain.

To assess canine exposure to spotted fever group rickettsiae in the central provinces of Spain, ticks removed from dogs were studied by immunofluorescence (IF) staining. Twenty-eight out of 65 (43.0%) samples from ticks were positive. Sera from 58 dogs were also collected and the presence of antibodies to Rickettsia conorii studied. Thirty-four (58.6%) dogs presented significant titers by IF. Surveillance data from these provinces show the presence of Boutonneuse fever cases during recent years, evidence that dogs could serve as an indicator of rickettsial activity in these areas.

Animals↗
PubMed1989

Identification of 'Old World' Leishmania by DNA recombinant probes.

Leishmania are usually identified by iso-enzyme analysis. This method works well, but there is a need for an additional, more simple, method of identification. Here we present data that show that in a Southern blot analysis, recombinant DNA probes in combination with certain restriction enzymes can differentiate between taxa of Leishmania. Probes based on clones selected from a L. infantum cDNA library gave characteristic patterns on Southern blots for reference strains of the different types of Leishmania found in Europe, Africa and Asia. Within the different taxa little or no variation was observed. Although the L. infantum derived probes showed a somewhat stronger hybridization for strains of the L. donovani complex, the signal obtained with most probes was satisfactory for L. major, L. aethiopica and L. tropica. Within the L. donovani complex none of the selected probes differentiated between isolates belonging to L. infantum, L. chagasi or L. donovani. Probes containing kinetoplast DNA showed considerable variation in hybridization within a taxon.

Animals↗
PubMed1987

In vitro chloroquine-resistant falciparum malaria in Malabo, Equatorial Guinea: case reports.

For many years the chloroquine-resistant problem in Africa was circumscribed to East Africa, but in the last two years it has been spreading progressively to the West. We report here the two first cases of chloroquine-resistant falciparum malaria imported into Spain from Equatorial Guinea. Both cases show a parasitological grade III resistance in a W.H.O. in vitro macrotest. The clinical recovery with the alternative treatment (Fansidar) was satisfactory.

Adolescent↗