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

Aphid derived sugars in the neotropical sandfly--Lutzomyia peruensis.

It is known that a sugar meal is a prerequisite for the transmission of Leishmania by sandflies in the laboratory. Lutzomyia peruensis the proven vector of Leishmania peruviana, was caught by aspiration from crevices in rocks near Chaute in the Rimac Valley, Peru, cryopreserved and analysed for sugars using HPLC. The major sugars present are glucose and fructose as well as smaller amounts of sucrose, maltose, melibiose, turanose and a trisaccharide, probably raffinose. The results indicate that the major carbohydrate sugar meal of Lutzomyia peruensis is aphid honeydew. This is the first report of such behaviour in Neotropical sandflies.

Persistence of hepatitis B antigen in Culex quinquefasciatus (Diptera: Culicidae).

Groups of wild-caught Culex quinquefaciatus Say, previously tested for the presence of hepatitis B surface antigen (HBsAg), were tested for the presence of hepatitis B e antigen (HBeAg). This antigen was detected at low levels in blood-fed, half-gravid, and gravid groups. A colony of Cx. quinquefasciatus was established in the laboratory and tested for the persistence of HBsAg and HBeAg. Five days after feeding on blood infected with HBsAg and HBeAg, 9 of 20 (45%) pools of Cx. quinquefasciatus were HBeAg-positive and 5 of 20 (25%) pools were HBeAg-positive; low levels of HBsAg and HBeAg were still detectable 28 d after the infective meal in 2 of 20 (10%) and 1 of 20 (5%) pools, respectively. A crude protease extract was prepared from colony mosquitoes, and the effect of this extract on HBsAg and HBeAg present in human serum was tested in vitro. After 20 h, tests for both antigens were still strongly positive. Low levels of HBsAg were detected in ovaries 7 d after infection. Salivary glands were HBsAg- and HBeAg-negative.

Separation of Psychodopygus carrerai carrerai and P. yucumensis (Diptera: Psychodidae) by gas chromatography of cuticular hydrocarbons.

Specimens of two species of sandfly, Psychodopygus carrerai carrerai and P. yucumensis, vectors of Leishmania braziliensis braziliensis in the subandean lowlands of Bolivia, were subjected to cuticular hydrocarbon analysis to ascertain if the technique could separate the females. A high degree of separation (87%) was obtained based on significant differences in the cuticular hydrocarbon composition of these two species. Statistical treatment of the data shows that these species, initially identified by the colour of the mesonotum, can also be distinguished by their hydrocarbons.

Immunolabeling of grapevine flavescence dorée MLO in salivary glands of Euscelidius variegatus: a light and electron microscopy study.

Flavescence dorée (FD), a grapevine yellows disease, is caused by a mycoplasma-like organism (MLO). A colloidal gold indirect immunolabeling technique identified MLO in salivary glands of a vector leafhopper, Euscelidius variegatus. After aldehyde fixation, tissue samples were prepared by cryoultramicrotomy or embedding in acrylic resins. Double fixation with aldehydes and osmium retroxide, followed by embedding in epon, was also performed. Thin or semi-thin serial sections were treated with polyclonal anti-FD-MLO rabbit antibodies, then with gold-conjugated anti-rabbit IgG. Labeling was revealed using the silver enhancement technique for light microscopy. MLO in frozen thin sections of glands were efficiently labeled. Optimal results were obtained with 4% paraformaldehyde-0.1% glutaraldehyde fixation and low-temperature embedding in LR White resin. Both scattered MLO and unusual dense forms of MLO were easily detected with the electron-dense gold probe. This method distinguished MLO from other membrane-limited bodies and provided a good tool for studying infection in large regions of FD-infected tissues by light microscopy.

Attachment behaviour of immatures of Mansonia annulifera (Theobald), 1901.

The detachment and reattachment of the immatures of M. annulifera with their host plants (hydrophytes) is a regular phenomenon. This occurs frequently with the same plant, or with a different one, throughout the larval span. The duration between detachment and reattachment varied from 30 sec to one hour and majority of them get reattached within a minute. This behaviour is instinctive and not found to be influenced by food availability. In the absence of hydrophyte, early immature stages survive relatively longer (192 h), when compared to the late ones.

Prevalence of bancroftian filariasis & its control by single course of diethyl carbamazine in a rural area in Tamil Nadu.

The prevalence of microfilaraemia, clinical spectrum of bancroftian filariasis and vector potential were studied in Vettavalam village in North Arcot district of Tamil Nadu. The effectiveness of selective therapy with diethyl carbamazine (DEC) in controlling filariasis in rural areas was also evaluated. The prevalence of microfilaraemia (mf rate) and disease (disease rate) was found to be 11.7 and 11.09 per cent respectively. Hydrocele was the dominant clinical sign in males and lymphoedema in females. The density of the vector Culex quinquefasciatus was 25.44 females/man-hour, and the infection and infectivity rates were 18.16 and 1.09 per cent respectively. All mf carriers detected after the mass blood survey were given a single course of DEC at the dosage of 6 mg/kg of body wt/day for 12 days. Only 61.6 per cent of them took the full course of DEC treatment. DEC therapy brought down the mf rate from 11.7 to 5.84 per cent after one month. In the absence of further treatment, there was no significant change in mf prevalence after one year.

The agglutination of erythrocytes and Leishmania parasites by sandfly gut extracts: evidence for lectin activity.

Lysates of heads, hind- and midguts of male and female Phlebotomus papatasi were found to contain lectins or lectin-like molecules capable of agglutinating human red blood cell types of the ABO(H) system and promastigotes of Leishmania aethiopica, L. major and L. donovani but not L. hertigi hertigi promastigotes or Crithidia fasciculata choanomastigotes. The agglutination of erythrocytes from the human O Rhesus positive blood group by sandfly midgut extracts was inhibited by two disaccharides; trehalose and turanose. This is the first report of haemagglutinating and parasite agglutinating activity in sandflies (Psychodidae).

Chemical analysis of compounds extracted from the tergal "spots" of Lutzomyia longipalpis from Brazil.

The chemical composition of the compounds contained in the tergal spots of Lutzomyia longipalpis was investigated. Four populations of L. longipalpis were examined, originating from: Sobral, Ceará, Brazil (one spot and two spot populations), Santarém, Pará, Brazil (one spot) and Marajó Island, Pará, Brazil (one spot). The tergal spots were dissected out, extracted in hexane and analysed on a gas chromatograph/mass spectrometer. Two compounds were found, identical to compounds found in earlier studies, but there was no correlation between number of tergal spots and type of compound present. It was suggested that the number of tergal spots could not be used as a marker for reproductively isolated populations, and that analysis of the compound present within the spots might be necessary to characterize potentially good vector populations.

A new method for identification of the animal origin of mosquito bloodmeals by the immunobinding of peroxidase-anti-peroxidase complexes on nitrocellulose.

A method is described for identification of the animal origin of mosquito bloodmeals (MBM). The immunoassay is named DOT-PAP, it makes use of nitrocellulose as solid phase and of peroxidase-anti-peroxidase soluble complexes as detectors. DOT-PAP includes a built-in absorbing system to remove possible cross-reactivities. The sensitivity of the assay is higher than that of precipitin test or ELISA, and it dispenses with machineries for the reading of results. The method requires nanogram amounts of antigen, therefore it lends itself to the identification of incomplete MBM and of 28 h digested MBM as well. The assay can be applied to different hematophagous arthropods and the small volumes of antigen used allow to scan a vast array of possible animal sources on the same bloodmeal.

Production in ascites fluid of biosynthetically labelled monoclonal antibody to Theileria parva sporozoites.

A hybridoma cell line has been previously produced which secretes monoclonal antibodies able to neutralize sporozoites of Theileria parva, the causative agent of East Coast fever of cattle. Cells from this line were injected intra-peritoneally into pristane-treated BALB/c mice. During the last 4 days of hybridoma cell growth, mice were given 4 daily intraperitoneal injections of a mixture of tritiated amino acids in order to biosynthetically radiolabel the monoclonal antibody being produced in ascites fluid. The specific activity of the antibody obtained was 100 mCi/mmol. The labelled antibody was used to detect, by autoradiography, a surface coat antigen of T. parva sporozoites in cryostat sections of Theileria-infected tick salivary glands. The method allows the preparation of large quantities of biosynthetically radiolabelled immunological probes for the detection of immunoreactive sites in biological specimens.