RESUMEN
Plague was confirmed in the United States from nine western states during 1995. Evidence of Yersinia pestis infection was identified in 28 species of wild or domestic mammals. Thirteen of the plague positive species were wild rodents; 15 were predators/carnivores. Yersinia pestis was isolated from eight species of fleas. Seven confirmed cases of human plague were reported in 1995 (New Mexico 3; California 2; Arizona and Oregon 1 each). Five of the seven cases were bubonic; one was septicemic and one a fatal pneumonic case. Months of onset ranged from March through August. In California, during 1995, plague was recorded from 15 of the 58 counties. Over 1,500 animals were tested, of which 208 were plague positive. These included 144 rodents and 64 predators/carnivores. Two confirmed human cases (one bubonic and one fatal pneumonic) occurred, both in Kern County. Case No. 1 was reported from the town of Tehachapi. The patient, a 23 year-old male resident, died following a diagnosis of plague pneumonia. The patient's source of plague infection could not be determined precisely. Field investigations revealed an extensive plague epizootic surrounding Tehachapi, an area of approximately 500-600 square miles (800-970 square kilometers). Case No. 2 was a 57 year-old female diagnosed with bubonic plague; she was placed on an antibiotic regimen and subsequently recovered. The patient lives approximately 20 miles (32 km) north of Tehachapi. Field investigations revealed evidence of a plague epizootic in the vicinity of the victim's residence and adjacent areas. Overall results of the joint field investigations throughout the entire Kern county area revealed a high rate of plague positive animals. Of the numerous samples submitted, 48 non-human samples were plague positive.
Asunto(s)
Peste/epidemiología , Adulto , Animales , California/epidemiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Peste/veterinaria , Estados Unidos/epidemiologíaRESUMEN
A survey carried out in Tonga, an area of hyperendemic subperiodic Wuchereria bancrofti filariasis, compared the diagnostic efficiency of the membrane-filtration and stained blood film techniques. Membrane filter concentration of 1 ml blood revealed a microfilaria rate that was approximately the same for all age groups, from 5 to 9 years old to greater than 50 years old, about 70%. The microfilaria rate by examination of stained 60 mm-3 thick blood films was lower for all age groups. Membrane filter concentration detected 7.8 times as many infections as thick film diagnosis in the 5- to 20- and 21- to 50-year-old groups, and 1.6 times in the greater than 50-year-old group. Concentration revealed the prsence of microfilariae in the blood of 5 of 8 patients with gross elephantiasis, whereas microfilariae were found in the stained thick-film of only 1 of these individuals.
Asunto(s)
Filariasis/diagnóstico , Filtración/métodos , Wuchereria bancrofti/aislamiento & purificación , Wuchereria/aislamiento & purificación , Adolescente , Adulto , Factores de Edad , Sangre/parasitología , Niño , Preescolar , Elefantiasis/diagnóstico , Elefantiasis/epidemiología , Femenino , Filariasis/epidemiología , Humanos , Masculino , Membranas Artificiales , Métodos , Persona de Mediana Edad , PolinesiaRESUMEN
An autogenous species belonging to the Aedes (Stegomyia) scutellaris subgroup was found on the island of Tafahi, Kingdom of Tonga. A subcolony was established at Johns Hopkins University, Baltimore, Md., USA, where cross-breeding experiments were conducted with the Samoan strain of A. polynesiensis. The cross between Tafahi females and A. polynesiensis males produced viable hybrid progeny, which were inbred through five generations. The reciprocal cross was not successful. F(1) Tafahi x A. polynesiensis hybrid males were backcrossed successfully to Tafahi females, but of the many eggs produced by backcrossing these F(1)TP males to A. polynesiensis females, only 0.7% hatched. Of the eggs produced by the F(2)TP male x A. polynesiensis female backcross, about 7% were viable. The results indicate a close genetic relationship between the Tafahi species and A. polynesiensis. The one-directional compatibility observed suggests the existence of cytoplasmic factors for sterility, which might eventually be useful in the control of members of the A. scutellaris complex.