Observaçöes preliminares sobre a paridade de Anopheles (Kerteszia) Cruzii / Preliminary abservations on Anopheles (Kerteszia) Cruzii parity

Consistiu-se em observaçöes de campo e de laboratório sendo que a primeira foi desenvolvida na localidade da Fazenda Folha Larga, município de Cananéia, Estado de Säo Paulo. As capturas foram feitas nos ambientes extra e peridomiciliares com isca humana em horário de pico máximo de atividade hematófaga de Anophles (Kerteszia) cruzii. Resultados preliminares obtidos em campo objetivaram determinar a paridade, enquanto que sob condiçöes laboratoriais procurou-se conhecer a duraçäo do ciclo gonotrófico, ambos considerados parâmetros implicados na determinaçäo da capacidade vetora de An. cruzii. Assim, pois, das 631 fêmeas dissecadas, 90,49 por cento rrevelaram-se nulíparas e somente 9,50 por cento uníparas, mostrando que a maior parte da populaçäo era constituída de indivíduos jovens e sem haver diferença significativa quanto a proporçäo de fêmeas uníparas nos diversos ambientes. No laboratório trabalhou-se com 1.158 larvas dessa espécie, oriundas de aproximadamente 600 bromélias. O período de desenvolvimento larvário foi de aproximadamente 40 dias. Desse material, 283 fêmeas foram alimentadas com sangue humano, sendo que 50 por cento conseguiu o seu desenvolvimento folicular completo com um único repasto sangüíneo. Outras 25 fêmeas, näo receberam alimentaçäo sangüínea e, quando dissecadas, todas apresentaram o seu primeiro folículo no estágio II de Christophers e Mer, provavelmente pela falta de estímulo sangüíneo. Além do mais, determinou-se que o tempo médio entre a alimentaçäo sangüínea e a oviposiçäo foi de 6 a 7 dias. Em vista disso, as observaçöes preliminares, possibilitam considerar esta espécie com razoável capacidade vetora, apesar da baixa longevidade, pois esta é provavelmente, compensada pela alta densidade

The distribution of circumsporozoite protein (CS) in Anopheles stephensi mosquitoes infected with Plasmodium falciparum malaria.

We monitored the distribution of Plasmodium falciparum circumsporozoite protein (CS) in Anopheles stephensi using an immunohistochemical method. An alkaline phosphatase-labeled monoclonal antibody, specific for the CS protein of P. falciparum, was incubated with tissue sections from infected and non-infected mosquitoes. Sections were stained for phosphatase activity using a new fuchsin/naphthol AS-BI phosphate capture system. Distribution of the CS protein in mosquitoes was dependent on the time after post-infective blood meal. CS protein was first detected in immature oocysts on the mosquito midgut. As oocysts differentiated to mature sporoblasts, detectable CS protein increased. Between 11-16 days post infective blood meal, CS protein was detected on the surface of sporozoites that were released into the hemolymph from oocysts. Although sporozoites were found throughout the hemocoel, they were most frequently associated with the salivary glands and flight muscle. Once in the salivary glands, sporozoites massed into bundles. The amount of CS protein associated with bundles of sporozoites was highly variable.

Estudio de la actividad hematofágica de Anopheles vestitipennis Dyar & Knab, 1906 (Diptera: Culicidae) / Study of hematophagic activity of Anopheles vestitipennis Dyar & Knab, 1906 (Diptera: Culicidae)

Se estudió la actividad hematofágica de Anopheles vestitipennis Dyar & Knab, 1906, en una localidad rural durante las épocas de seca y lluvia, a través de colectas intra y extradomiciliarias con cebo humano en el horario de las 19:00 a las 7:00 horas. La especie presentó preferencia por la alimentación intradomiciliaria (endofágica) en ambas épocas. En el período lluvioso existieron 2 picos de máxima actividad dentro de las casas de las 23:00 a las 24:00 horas y de las 2:00 a las 3:00 horas (el primero coincide con el pico que ocurre en el exterior). En la época de seca el pico de la actividad en el exterior ocurrió de las 24:00 a las 1:00 horas, mientras que para el interior fue de las 2:00 a las 3:00 horas

Isolation and characterization of histones from Anopheles albimanus Weidemann.

1. Histones from Anopheles albimanus adults were prepared by a combination of techniques including chromatin isolation and selective extractions. 2. The anopheline histones were identified on acid urea gels by comparing their electrophoretic profile with that of calf thymus histones and histones isolated from other tissue. 3. Excellent separation of histones was obtained after the extractions by a single electrophoretic run. 4. In addition to the five major classes of histones found in eukaryotes, a sixth class was detected and tentatively identified as histone H5. 5. This is the first report of histone H5 and its function in insects.

Techniques for mitochondrial and ribosomal DNA analysis of anopheline mosquitoes.

Methods are described for the isolation of mitochondrial and total cellular DNA from mosquitoes. The mitochondrial and ribosomal DNA restriction patterns could be detected in the total DNA of an individual mosquito by the use of cloned probes. DNA restriction analysis may prove to be a useful alternative to isozyme electrophoresis for the study of insect population genetics.

Ribosomal DNA-probes differentiate five cryptic species in the Anopheles gambiae complex.

This study describes the use of ribosomal DNA probes to identify the species of individual mosquitoes in the Anopheles gambiae complex, a group of six morphologically identical mosquito species among which are two of the principal vectors of malaria in Africa. The DNA probes are sequences of DNA derived from the ribosomal genes of An. gambiae. Each probe reveals a different sized restriction enzyme fragment specific to each of the five species in the complex that were examined in this study: An. gambiae, An. arabiensis, An. quadriannulatus, An. melas and An. merus. The probes detect highly repeated sequences of DNA, thus the method is sufficiently sensitive to be applied to a small portion of a mosquito. Furthermore, because the DNA can be extracted from desiccated or alcohol preserved specimens, the test is compatible with other mosquito assays performed on dried specimens such as blood meal and malaria sporozoite antigen ELISAs. Determination of the nucleotide sequences that underlie the species-specific restriction enzyme site differences detected by these probes will lead to the development of synthetic DNA probes that can be used to identify an individual mosquito to species on the basis of a simple dot-blot or squash-blot.

Distribucion y bionomia de los anofelinos de la Costa Pacifica de Colombia / Distribution and binomia of anopheles from Colombian Pacific Coast

Se realizaron colecciones de adultos y larvas de Anpheles entre 1982 y 1985 en 41 localidades con antecedentes de transmision de malaria en la costa colombiana del Oceano Pacifico, en los departamentos de Choco, Valle del Cauca y Narino. De las 21 especies de anofelinos informados para estos departamentos, 19 se obtuvieron en este estudio. En capturas con cebo humano intradomiciliar y peridomiciliar, hubo 13 especies, siendo las mas abundantes en su orden A.albimanus, A.pseudopunctipennis, A.fluminensis, A.strodei y A.punctimacula, que en conjunto constituyeron 96% de los 6398 especimenes en total. Se informa la actividad de picadura por hora e indices de exofilia de las especies colectadas. Se colectaron 677 larvas de estadios III y IV, correspondientes a 14 especies. A. albimanus represento 73% de los especimenes. Se dan datos sobre preferencias por varios tipos de criaderos y asociaciones de especies. A.albimanus fue el anofelino encontrado en mayor numero tanto en larvas como en adultos y la especie mas ampliamente distribuida en la costa pacifica de Colombia

Biologia de anofelinos. XI. Estudos em populaçöes de anopheles e controle da malária em Ariquemes (Rondônia)

Säo apresentados dados sobre inquérito entomológico para espécies de Anopheles realizado no Município de Ariquemes e discutida a incidência da malária neste Município e no Estado de Rondônia. Os resultados do inquérito entomológico na zona urbana de Ariquemes evidenciaram a diversidade de espécies nos diferentes Setores, possibilitando verificar o grau de penetraçäo dos anofelinos na cidade. Säo correlacionados casos autóctones de malária e a presença do principal vetor da malária humana na Amazônia, o Anopheles darlingi. A dinâmica da transmissäo da malária na zona urbana é enfocada, discutindo-se os riscos verificados para cada Setor e säo apresentadas estratégias de controle, ao nível do vetor, fundamentadas no manuseio do habitat. Na zona rural estäo sendo estudados parâmetros populacionais realcionados (1) `a atividade de picar, abrigo natural, sítios de reproduçäo e deslocamento para hematofagia; e (2) comportamento das populaçöes para atividade hematófoga e preferências alimentares. Os resultados, embora preliminares, evidenciam variaçöes na densidade populacional e na diversidade de espécies, as quais devem estar relacionadas `a mudanças estacionais. Variaçöes nas preferências alimentares das espécies também foram verificadas, sendo constatada elevada antropofilia de A. darlingi. Dois parâmetros relevantes na atividade hematófaga de A. darlingi foram detectados, observando-se que os anofelinos estäo penetrando nas habitaçöes pelas partes inferiores e que näo estäo pousando nas paredes com DDT. Na vegetaçäo circundante `as habitaçöes, está havendo preferência para locais de pouso, que podem ser alternativamente alto e baixo

Mosquito protein microassay. I. Protein determinations from small portions of single-mosquito homogenates.

A microassay is described for determining protein levels in individual mosquitoes. This method requires only a small portion of a homogenate of a single mosquito. Protein levels in Anopheles albimanus are positively correlated with body weight. Protein levels for different geographic strains of Anopheles albimanus and different generations of laboratory rearings are compared.

Mosquito protein microassay. II. Modification for potential field use.

A simple microassay is described for determining protein levels in individual mosquitoes; this method should be useful on a routine basis in the field. This method requires only a small portion of a homogenate of a single mosquito. Sugar-fed adult female Anopheles albimanus showed a slow decline in protein level for 14 days post-emergence. Blood volumes and blood-meal protein levels were microassayed, and changes in protein level were monitored throughout the reproductive cycle. Blood-fed Anopheles albimanus protein levels return only slowly to pre-feeding levels following egg deposition.

Value of cuticular and internal hydrocarbons for the identification of larvae of Anopheles gambiae Giles, Anopheles arabiensis Patton and Anopheles melas Theobald.

Gas chromatographic profiles of the cuticular and internal lipids extracted from 4th-instar larvae of the Anopheles gambiae complex have shown quantitative differences in their chain length distributions. For example, hydrocarbons extracted with 95% ethanol showed relative differences in peak heights eluting at Kovat indices (KI's) 2840 (An. gambiae 1.21, An. arabiensis 1.39 and An. melas 1.14) and 3150 (An. gambiae 6.73, An. arabiensis 13.40 and An. melas 13.50). However, while using the non-hydrocarbon fractions, differences were obtained at a KI of 2160 (An. gambiae 0.45, An. arabiensis 0.45 and An. melas 1.16) and at a KI of 2430 (An. gambiae 2.90, An. arabiensis 1.81 and An. melas 3.50). Utilizing the total ethanol extract and omitting the TLC (thin layer chromatography) step, thus saving four hours of analysis time, good separation was achieved at a KI of 2060 (An. gambiae 0.60, An. arabiensis and An. melas 0.0) and at a KI of 2430 (An. gambiae 1.13, An. arabiensis 0.69 and An. melas 1.59). Other differences were also noted in the profiles which could identify one or more of the three species. Good separation could be made on single larvae as well as on small batches of specimens. It was concluded that analysis of cuticular and internal lipids provides a useful biochemical method of distinguishing larvae of these species, but further studies are needed on these and other species of the An. gambiae complex collected from many localities in Africa.

Identification of mosquitoes of Anopheles gambiae species complex A and B by analysis of cuticular components.

Two important vectors of malaria in Africa, Anopheles gambiae and Anopheles arabiensis (Diptera: Culicidae), often occur sympatrically and cannot be distinguished morphologically. A chemical method was developed to identify individual laboratory-reared adult males or females of either species by extraction and analysis of cuticular components with gas chromatography. Statistically significant differences were seen between species when selected pairs of peaks were compared.

Differentiation between species of the Anopheles gambiae Giles complex (Diptera: Culicidae) by analysis of cuticular hydrocarbons.

Lipids were extracted from 500 female Anopheles gambiae and An. arabiensis in n-hexane and the extracts examined by gas chromatographic analysis using a glass column packed with 3% OV-1 on a 100-200 mesh Gas Chrom Q which was maintained at 225 degrees C. Cuticular hydrocarbons consisted mostly of unbranched paraffins. There were differences between the distribution of compounds with 25-29 carbons. After adjusting the C27 peak to 100%, hydrocarbons C26 and C29 represent heights of 80 and 69% in An. gambiae compared with values of 49 and 95 % in An. arabiensis. Other small but consistent differences were also found. Investigations are being performed on extracts from smaller samples and on other species within the An. gambiae complex.

Hemolymph of Anopheles stephensi from noninfected and Plasmodium berghei-infected mosquitoes. 3. Carbohydrates.

Determinations were made of carbohydrates in hemolymph collected from adult female mosquitoes (Anopheles stephensi). First the hemolymph was fractionated by extraction and precipitation procedures, after which qualitative and quantitative determinations of carbohydrates were made by thin layer chromatography. The most abundant sugars found in the hemolymph were glucose and trehalose, though maltose, glucuronic acid, and inositol could be found after the mosquitoes took blood meals. After the mosquitoes ingested a noninfected blood meal, their hemolymph sugar levels rose almost 4-fold. There was less of an increase following a blood meal infected with the rodent malaria parasite, Plasmodium berghei. Depletion of sugars in the hemolymph of infected mosquitoes may result from direct utilization of sugar by the malaria parasite developing within the mosquito.

Hemolymph of Anopheles stephensi from uninfected and Plasmodium berghei-infected mosquitoes. 2. Free amino acids.

Determinations were made of free amino acids in hemolymph collected from adult female Anopheles stephensi mosquitoes. The hemolymph first was fractionated by extraction and precipitation procedures, after which qualitative determinations of free amino acids were made by high voltage thin layer electrophoresis, and thin layer chromatography. Subsequent quantitative determinations were made with an automatic amino acid analyzer. The concentration of total free amino acids in the hemolymph rose 60--70% after the mosquito took a blood meal, and remained relatively constant thereafter. When mosquitoes took a blood meal infected with the rodent malaria parasite Plasmodium berghei, the rise in total free amino acids was only 15--25%. The chief differences that occurred with individual free amino acids was that infected mosquitoes had greater increases in arginine, greater decreases in valine and histidine, and a total loss of detectable methionine.

Studies on multiple feeding by Anopheles gambiae s.l. in a Sudan savanna area of north Nigeria.

The detection of haptoglobins in Anopheles gambiae s.l. has been used to obtain an estimate of the incidence of multiple feeding for the village of Barmawa, Garki District, Kano State, Nigeria. The results indicated that the incidence of multiple feeding was approximately 10% but problems were encountered by the high incidence of ahaptoglobinaemia in the population. In four villages in Garki District the incidence of ahaptoglobinaemia varied between 65 and 76% while in young children and personnel under constant malaria chemoprophylaxis it was less than 30%. A strong correlation between ahaptoglobinaemia and malaria infections was seen. The results show evidence of selection of hosts by mosquitoes at Barmawa although this does not necessarily imply a preference per se. The results provide evidence of movement of blood-fed mosquitoes, between houses and from houses to resting sites.